diff --git a/src/slic3r/CMakeLists.txt b/src/slic3r/CMakeLists.txt index 9e153c1792..aed941f783 100644 --- a/src/slic3r/CMakeLists.txt +++ b/src/slic3r/CMakeLists.txt @@ -752,7 +752,9 @@ target_link_libraries(libslic3r_gui libslic3r cereal::cereal imgui imguizmo mini if (MSVC) - target_link_libraries(libslic3r_gui Setupapi.lib) + # Iphlpapi/Ws2_32 are required by the vendored mjansson/mdns library + # (GetAdaptersAddresses + Winsock2) used by CrealityHostDiscovery. + target_link_libraries(libslic3r_gui Setupapi.lib Iphlpapi.lib Ws2_32.lib) elseif (CMAKE_SYSTEM_NAME STREQUAL "Linux") FIND_LIBRARY(WAYLAND_SERVER_LIBRARIES NAMES wayland-server) FIND_LIBRARY(WAYLAND_EGL_LIBRARIES NAMES wayland-egl) diff --git a/src/slic3r/Utils/mdns/NOTICE.md b/src/slic3r/Utils/mdns/NOTICE.md new file mode 100644 index 0000000000..60ad15c29a --- /dev/null +++ b/src/slic3r/Utils/mdns/NOTICE.md @@ -0,0 +1,39 @@ +# mDNS / DNS-SD library + +The four files in this directory implement mDNS / DNS-SD lookup and are +vendored from third-party sources: + +## mdns.h, mdns.c + +mDNS / DNS-SD lookup library by Mattias Jansson. Originally released to +the public domain at https://github.com/mjansson/mdns. + +The exact files here were taken from CrealityOfficial/CrealityPrint +v7.1.1, which split the upstream header-only library into separate +declaration (mdns.h) and implementation (mdns.c) files. + +- Source: https://github.com/mjansson/mdns +- License: Public domain (no restrictions on use) + +## cxmdns.h, cxmdns.cpp + +Thin C++ wrapper over mdns.{h,c} that exposes a single function: + + std::vector syncDiscoveryService( + const std::vector& prefix); + +It sends a DNS-SD meta-discovery query (`_services._dns-sd._udp.local.`), +listens for ~5 seconds, and returns `{ip, service_name}` for every +service announcement whose name contains any of the given prefixes. + +OrcaSlicer uses this to find Creality K-series printers on the LAN +(service-name prefix "Creality"), since K-series firmware announces +each printer under a per-device-unique service type +`_Creality-._udp.local.` that no fixed-name query can +target. + +- Source: CrealityOfficial/CrealityPrint v7.1.1 + `src/slic3r/GUI/print_manage/utils/cxmdns.{h,cpp}` +- License: GNU AGPL-3.0 (compatible with OrcaSlicer's AGPL-3.0; see + top-level LICENSE.txt) +- Imported: 2026-05-19 diff --git a/src/slic3r/Utils/mdns/cxmdns.cpp b/src/slic3r/Utils/mdns/cxmdns.cpp new file mode 100644 index 0000000000..f505eaa0b2 --- /dev/null +++ b/src/slic3r/Utils/mdns/cxmdns.cpp @@ -0,0 +1,256 @@ +#include"cxmdns.h" +#include"mdns.h" +#ifdef _WIN32 +#define _CRT_SECURE_NO_WARNINGS 1 +#endif + +#include +#include +#include +#include + +#ifdef _WIN32 +#include +#include +#define sleep(x) Sleep(x * 1000) +#else +#include +#include +#include +#endif + +// Alias some things to simulate recieving data to fuzz library +#if defined(MDNS_FUZZING) +#define recvfrom(sock, buffer, capacity, flags, src_addr, addrlen) ((mdns_ssize_t)capacity) +#define printf +#endif + +#include "mdns.h" + +#if defined(MDNS_FUZZING) +#undef recvfrom +#endif + +namespace cxnet +{ + template + mdns_record_callback_fn lambda2function(F lambda) + { + static auto lambdabak = lambda; + return [](int sock, const struct sockaddr* from, size_t addrlen, + mdns_entry_type_t entry, uint16_t query_id, uint16_t rtype, + uint16_t rclass, uint32_t ttl, const void* data, size_t size, + size_t name_offset, size_t name_length, size_t record_offset, + size_t record_length, void* user_data)->int {lambdabak(sock, from, addrlen, entry, query_id, rtype, rclass, ttl, data, size, name_offset, name_length, record_offset, record_length, user_data); return 0; }; + } + + volatile sig_atomic_t running = 1; +#ifdef _WIN32 + BOOL console_handler(DWORD signal) { + if (signal == CTRL_C_EVENT) { + running = 0; + } + return TRUE; + } +#else + void signal_handler(int signal) { + running = 0; + } +#endif + + void recvMachineInfoFromSocket(int sock, void* buffer, size_t capacity, const std::vector& prefix, std::vector& retmachineInfos, int recIndex) + { + struct sockaddr_in6 addr; + struct sockaddr* saddr = (struct sockaddr*)&addr; + socklen_t addrlen = sizeof(addr); + memset(&addr, 0, sizeof(addr)); +#ifdef __APPLE__ + saddr->sa_len = sizeof(addr); +#endif + mdns_ssize_t ret = recvfrom(sock, (char*)buffer, (mdns_size_t)capacity, 0, saddr, &addrlen); + if (ret <= 0) + return; + + size_t data_size = (size_t)ret; + //size_t records = 0; + const uint16_t* data = (uint16_t*)buffer; + + uint16_t query_id = mdns_ntohs(data++); + uint16_t flags = mdns_ntohs(data++); + uint16_t questions = mdns_ntohs(data++); + uint16_t answer_rrs = mdns_ntohs(data++); + uint16_t authority_rrs = mdns_ntohs(data++); + uint16_t additional_rrs = mdns_ntohs(data++); + + // According to RFC 6762 the query ID MUST match the sent query ID (which is 0 in our case) + if (query_id || (flags != 0x8400)) + return; // Not a reply to our question + + // It seems some implementations do not fill the correct questions field, + // so ignore this check for now and only validate answer string + // if (questions != 1) + // return 0; + + int i; + for (i = 0; i < questions; ++i) { + size_t offset = MDNS_POINTER_DIFF(data, buffer); + size_t verify_offset = 12; + // Verify it's our question, _services._dns-sd._udp.local. + if (!mdns_string_equal(buffer, data_size, &offset, mdns_services_query, + sizeof(mdns_services_query), &verify_offset)) + return; + data = (const uint16_t*)MDNS_POINTER_OFFSET(buffer, offset); + + uint16_t rtype = mdns_ntohs(data++); + uint16_t rclass = mdns_ntohs(data++); + + // Make sure we get a reply based on our PTR question for class IN + if ((rtype != MDNS_RECORDTYPE_PTR) || ((rclass & 0x7FFF) != MDNS_CLASS_IN)) + return; + } + + for (i = 0; i < answer_rrs; ++i) { + size_t offset = MDNS_POINTER_DIFF(data, buffer); + size_t verify_offset = 12; + // Verify it's an answer to our question, _services._dns-sd._udp.local. + size_t name_offset = offset; + int is_answer = mdns_string_equal(buffer, data_size, &offset, mdns_services_query, + sizeof(mdns_services_query), &verify_offset); + if (!is_answer && !mdns_string_skip(buffer, data_size, &offset)) + break; + size_t name_length = offset - name_offset; + if ((offset + 10) > data_size) + return; + data = (const uint16_t*)MDNS_POINTER_OFFSET(buffer, offset); + + uint16_t rtype = mdns_ntohs(data++); + uint16_t rclass = mdns_ntohs(data++); + uint32_t ttl = mdns_ntohl(data); + data += 2; + uint16_t length = mdns_ntohs(data++); + if (length > (data_size - offset)) + return; + + static char addrbuf[64]; + static char entrybuf[256]; + static char namebuf[256]; + + if (is_answer) { + offset = MDNS_POINTER_DIFF(data, buffer); + (void)sizeof(sock); + (void)sizeof(query_id); + (void)sizeof(name_length); + //(void)sizeof(0); + mdns_string_t fromaddrstr = ip_address_to_string(addrbuf, sizeof(addrbuf), saddr, addrlen); + mdns_string_t entrystr = + mdns_string_extract(buffer, data_size, &name_offset, entrybuf, sizeof(entrybuf)); + if (rtype == MDNS_RECORDTYPE_PTR) { + mdns_string_t namestr = mdns_record_parse_ptr(buffer, data_size, offset, length, + namebuf, sizeof(namebuf)); + if (!namestr.str || namestr.length == 0) { + return; + } + const std::string answer_name(namestr.str, namestr.length); + bool bFound = false; + for (const auto& item : prefix) + { + if (answer_name.find(item) != std::string::npos) + bFound = true; + } + if (!bFound) + { + return; + } + + char ip[16] = { 0 }; + sscanf(fromaddrstr.str, "%[^:]", ip); + retmachineInfos.push_back({ ip, answer_name }); + } + } + } + } + + std::vector syncDiscoveryService(const std::vector& prefix) + { + std::vector retmachineInfos; + const char* hostname = "cxslice-host"; + // Initialize network environment +#ifdef _WIN32 + WORD versionWanted = MAKEWORD(1, 1); + WSADATA wsaData; + if (WSAStartup(versionWanted, &wsaData)) { + printf("Failed to initialize WinSock\n"); + return retmachineInfos; + } + char hostname_buffer[256]; + DWORD hostname_size = (DWORD)sizeof(hostname_buffer); + if (GetComputerNameA(hostname_buffer, &hostname_size)) + hostname = hostname_buffer; + SetConsoleCtrlHandler(console_handler, TRUE); +#else + char hostname_buffer[256]; + size_t hostname_size = sizeof(hostname_buffer); + if (gethostname(hostname_buffer, hostname_size) == 0) + hostname = hostname_buffer; + signal(SIGINT, signal_handler); +#endif + int sockets[32]; + int num_sockets = open_client_sockets(sockets, sizeof(sockets) / sizeof(sockets[0]), 0); + if (num_sockets <= 0) { + printf("Failed to open any client sockets\n"); +#ifdef _WIN32 + WSACleanup(); +#endif + return retmachineInfos; + } + printf("Opened %d socket%s for DNS-SD\n", num_sockets, num_sockets > 1 ? "s" : ""); + printf("Sending DNS-SD discovery\n"); + for (int isock = 0; isock < num_sockets; ++isock) { + if (mdns_discovery_send(sockets[isock])) + printf("Failed to send DNS-DS discovery: %s\n", strerror(errno)); + } + size_t capacity = 2048; + void* buffer = malloc(capacity); + size_t recordNum = 0; + void* user_data = 0; + + // This is a simple implementation that loops for 5 seconds or as long as we get replies + int res; + printf("Reading DNS-SD replies\n"); + do { + struct timeval timeout; + timeout.tv_sec = 5; + timeout.tv_usec = 0; + + int nfds = 0; + fd_set readfs; + FD_ZERO(&readfs); + for (int isock = 0; isock < num_sockets; ++isock) { + if (sockets[isock] >= nfds) + nfds = sockets[isock] + 1; + FD_SET(sockets[isock], &readfs); + } + res = select(nfds, &readfs, 0, 0, &timeout); + if (res > 0) { + for (int isock = 0; isock < num_sockets; ++isock) { + if (FD_ISSET(sockets[isock], &readfs)) { + // records += mdns_discovery_recv(sockets[isock], buffer, capacity, query_callback, + // 0); + recvMachineInfoFromSocket(sockets[isock], buffer, capacity, prefix, retmachineInfos, isock); + recordNum++; + } + } + } + } while (res > 0); + + free(buffer); + // + for (int isock = 0; isock < num_sockets; ++isock) + mdns_socket_close(sockets[isock]); + printf("Closed socket%s\n", num_sockets ? "s" : ""); +#ifdef _WIN32 + WSACleanup(); +#endif + return std::move(retmachineInfos); + } +} diff --git a/src/slic3r/Utils/mdns/cxmdns.h b/src/slic3r/Utils/mdns/cxmdns.h new file mode 100644 index 0000000000..e0f9c1c3dc --- /dev/null +++ b/src/slic3r/Utils/mdns/cxmdns.h @@ -0,0 +1,16 @@ +#ifndef _CX_MDNS_H +#define _CX_MDNS_H +#include +#include + +namespace cxnet +{ + struct machine_info + { + std::string machineIp; + std::string answer; + }; + + std::vector syncDiscoveryService(const std::vector& prefix); +} +#endif \ No newline at end of file diff --git a/src/slic3r/Utils/mdns/mdns.c b/src/slic3r/Utils/mdns/mdns.c new file mode 100644 index 0000000000..089b495176 --- /dev/null +++ b/src/slic3r/Utils/mdns/mdns.c @@ -0,0 +1,1263 @@ + +#ifdef _WIN32 +#define _CRT_SECURE_NO_WARNINGS 1 +#endif + +#include + +#include +#include + +#ifdef _WIN32 +#include +#include +#define sleep(x) Sleep(x * 1000) +#else +#include +#include +#include +#endif + +// Alias some things to simulate recieving data to fuzz library +#if defined(MDNS_FUZZING) +#define recvfrom(sock, buffer, capacity, flags, src_addr, addrlen) ((mdns_ssize_t)capacity) +#define printf +#endif + +#include "mdns.h" + +#if defined(MDNS_FUZZING) +#undef recvfrom +#endif + +static char addrbuffer[64]; +static char entrybuffer[256]; +static char namebuffer[256]; +static char sendbuffer[1024]; +static mdns_record_txt_t txtbuffer[128]; + +static struct sockaddr_in service_address_ipv4; +static struct sockaddr_in6 service_address_ipv6; + +static int has_ipv4; +static int has_ipv6; + +volatile sig_atomic_t running = 1; + +// Data for our service including the mDNS records +typedef struct { + mdns_string_t service; + mdns_string_t hostname; + mdns_string_t service_instance; + mdns_string_t hostname_qualified; + struct sockaddr_in address_ipv4; + struct sockaddr_in6 address_ipv6; + int port; + mdns_record_t record_ptr; + mdns_record_t record_srv; + mdns_record_t record_a; + mdns_record_t record_aaaa; + mdns_record_t txt_record[2]; +} service_t; + +mdns_string_t +ipv4_address_to_string(char* buffer, size_t capacity, const struct sockaddr_in* addr, + size_t addrlen) { + char host[NI_MAXHOST] = {0}; + char service[NI_MAXSERV] = {0}; + int ret = getnameinfo((const struct sockaddr*)addr, (socklen_t)addrlen, host, NI_MAXHOST, + service, NI_MAXSERV, NI_NUMERICSERV | NI_NUMERICHOST); + int len = 0; + if (ret == 0) { + if (addr->sin_port != 0) + len = snprintf(buffer, capacity, "%s:%s", host, service); + else + len = snprintf(buffer, capacity, "%s", host); + } + if (len >= (int)capacity) + len = (int)capacity - 1; + mdns_string_t str; + str.str = buffer; + str.length = len; + return str; +} + +static mdns_string_t +ipv6_address_to_string(char* buffer, size_t capacity, const struct sockaddr_in6* addr, + size_t addrlen) { + char host[NI_MAXHOST] = {0}; + char service[NI_MAXSERV] = {0}; + int ret = getnameinfo((const struct sockaddr*)addr, (socklen_t)addrlen, host, NI_MAXHOST, + service, NI_MAXSERV, NI_NUMERICSERV | NI_NUMERICHOST); + int len = 0; + if (ret == 0) { + if (addr->sin6_port != 0) + len = snprintf(buffer, capacity, "[%s]:%s", host, service); + else + len = snprintf(buffer, capacity, "%s", host); + } + if (len >= (int)capacity) + len = (int)capacity - 1; + mdns_string_t str; + str.str = buffer; + str.length = len; + return str; +} + +mdns_string_t +ip_address_to_string(char* buffer, size_t capacity, const struct sockaddr* addr, size_t addrlen) { + if (addr->sa_family == AF_INET6) + return ipv6_address_to_string(buffer, capacity, (const struct sockaddr_in6*)addr, addrlen); + return ipv4_address_to_string(buffer, capacity, (const struct sockaddr_in*)addr, addrlen); +} + +// Callback handling parsing answers to queries sent +int +query_callback(int sock, const struct sockaddr* from, size_t addrlen, mdns_entry_type_t entry, + uint16_t query_id, uint16_t rtype, uint16_t rclass, uint32_t ttl, const void* data, + size_t size, size_t name_offset, size_t name_length, size_t record_offset, + size_t record_length, void* user_data) { + (void)sizeof(sock); + (void)sizeof(query_id); + (void)sizeof(name_length); + (void)sizeof(user_data); + mdns_string_t fromaddrstr = ip_address_to_string(addrbuffer, sizeof(addrbuffer), from, addrlen); + const char* entrytype = (entry == MDNS_ENTRYTYPE_ANSWER) ? + "answer" : + ((entry == MDNS_ENTRYTYPE_AUTHORITY) ? "authority" : "additional"); + mdns_string_t entrystr = + mdns_string_extract(data, size, &name_offset, entrybuffer, sizeof(entrybuffer)); + if (rtype == MDNS_RECORDTYPE_PTR) { + mdns_string_t namestr = mdns_record_parse_ptr(data, size, record_offset, record_length, + namebuffer, sizeof(namebuffer)); + printf("%.*s : %s %.*s PTR %.*s rclass 0x%x ttl %u length %d\n", + MDNS_STRING_FORMAT(fromaddrstr), entrytype, MDNS_STRING_FORMAT(entrystr), + MDNS_STRING_FORMAT(namestr), rclass, ttl, (int)record_length); + } else if (rtype == MDNS_RECORDTYPE_SRV) { + mdns_record_srv_t srv = mdns_record_parse_srv(data, size, record_offset, record_length, + namebuffer, sizeof(namebuffer)); + printf("%.*s : %s %.*s SRV %.*s priority %d weight %d port %d\n", + MDNS_STRING_FORMAT(fromaddrstr), entrytype, MDNS_STRING_FORMAT(entrystr), + MDNS_STRING_FORMAT(srv.name), srv.priority, srv.weight, srv.port); + } else if (rtype == MDNS_RECORDTYPE_A) { + struct sockaddr_in addr; + mdns_record_parse_a(data, size, record_offset, record_length, &addr); + mdns_string_t addrstr = + ipv4_address_to_string(namebuffer, sizeof(namebuffer), &addr, sizeof(addr)); + printf("%.*s : %s %.*s A %.*s\n", MDNS_STRING_FORMAT(fromaddrstr), entrytype, + MDNS_STRING_FORMAT(entrystr), MDNS_STRING_FORMAT(addrstr)); + } else if (rtype == MDNS_RECORDTYPE_AAAA) { + struct sockaddr_in6 addr; + mdns_record_parse_aaaa(data, size, record_offset, record_length, &addr); + mdns_string_t addrstr = + ipv6_address_to_string(namebuffer, sizeof(namebuffer), &addr, sizeof(addr)); + printf("%.*s : %s %.*s AAAA %.*s\n", MDNS_STRING_FORMAT(fromaddrstr), entrytype, + MDNS_STRING_FORMAT(entrystr), MDNS_STRING_FORMAT(addrstr)); + } else if (rtype == MDNS_RECORDTYPE_TXT) { + size_t parsed = mdns_record_parse_txt(data, size, record_offset, record_length, txtbuffer, + sizeof(txtbuffer) / sizeof(mdns_record_txt_t)); + for (size_t itxt = 0; itxt < parsed; ++itxt) { + if (txtbuffer[itxt].value.length) { + printf("%.*s : %s %.*s TXT %.*s = %.*s\n", MDNS_STRING_FORMAT(fromaddrstr), + entrytype, MDNS_STRING_FORMAT(entrystr), + MDNS_STRING_FORMAT(txtbuffer[itxt].key), + MDNS_STRING_FORMAT(txtbuffer[itxt].value)); + } else { + printf("%.*s : %s %.*s TXT %.*s\n", MDNS_STRING_FORMAT(fromaddrstr), entrytype, + MDNS_STRING_FORMAT(entrystr), MDNS_STRING_FORMAT(txtbuffer[itxt].key)); + } + } + } else { + printf("%.*s : %s %.*s type %u rclass 0x%x ttl %u length %d\n", + MDNS_STRING_FORMAT(fromaddrstr), entrytype, MDNS_STRING_FORMAT(entrystr), rtype, + rclass, ttl, (int)record_length); + } + return 0; +} + +// Callback handling questions incoming on service sockets +static int +service_callback(int sock, const struct sockaddr* from, size_t addrlen, mdns_entry_type_t entry, + uint16_t query_id, uint16_t rtype, uint16_t rclass, uint32_t ttl, const void* data, + size_t size, size_t name_offset, size_t name_length, size_t record_offset, + size_t record_length, void* user_data) { + (void)sizeof(ttl); + if (entry != MDNS_ENTRYTYPE_QUESTION) + return 0; + + const char dns_sd[] = "_services._dns-sd._udp.local."; + const service_t* service = (const service_t*)user_data; + + mdns_string_t fromaddrstr = ip_address_to_string(addrbuffer, sizeof(addrbuffer), from, addrlen); + + size_t offset = name_offset; + mdns_string_t name = mdns_string_extract(data, size, &offset, namebuffer, sizeof(namebuffer)); + + const char* record_name = 0; + if (rtype == MDNS_RECORDTYPE_PTR) + record_name = "PTR"; + else if (rtype == MDNS_RECORDTYPE_SRV) + record_name = "SRV"; + else if (rtype == MDNS_RECORDTYPE_A) + record_name = "A"; + else if (rtype == MDNS_RECORDTYPE_AAAA) + record_name = "AAAA"; + else if (rtype == MDNS_RECORDTYPE_TXT) + record_name = "TXT"; + else if (rtype == MDNS_RECORDTYPE_ANY) + record_name = "ANY"; + else + return 0; + printf("Query %s %.*s\n", record_name, MDNS_STRING_FORMAT(name)); + + if ((name.length == (sizeof(dns_sd) - 1)) && + (strncmp(name.str, dns_sd, sizeof(dns_sd) - 1) == 0)) { + if ((rtype == MDNS_RECORDTYPE_PTR) || (rtype == MDNS_RECORDTYPE_ANY)) { + // The PTR query was for the DNS-SD domain, send answer with a PTR record for the + // service name we advertise, typically on the "<_service-name>._tcp.local." format + + // Answer PTR record reverse mapping "<_service-name>._tcp.local." to + // ".<_service-name>._tcp.local." + mdns_record_t answer = { + .name = name, .type = MDNS_RECORDTYPE_PTR, .data.ptr.name = service->service}; + + // Send the answer, unicast or multicast depending on flag in query + uint16_t unicast = (rclass & MDNS_UNICAST_RESPONSE); + printf(" --> answer %.*s (%s)\n", MDNS_STRING_FORMAT(answer.data.ptr.name), + (unicast ? "unicast" : "multicast")); + + if (unicast) { + mdns_query_answer_unicast(sock, from, addrlen, sendbuffer, sizeof(sendbuffer), + query_id, rtype, name.str, name.length, answer, 0, 0, 0, + 0); + } else { + mdns_query_answer_multicast(sock, sendbuffer, sizeof(sendbuffer), answer, 0, 0, 0, + 0); + } + } + } else if ((name.length == service->service.length) && + (strncmp(name.str, service->service.str, name.length) == 0)) { + if ((rtype == MDNS_RECORDTYPE_PTR) || (rtype == MDNS_RECORDTYPE_ANY)) { + // The PTR query was for our service (usually "<_service-name._tcp.local"), answer a PTR + // record reverse mapping the queried service name to our service instance name + // (typically on the ".<_service-name>._tcp.local." format), and add + // additional records containing the SRV record mapping the service instance name to our + // qualified hostname (typically ".local.") and port, as well as any IPv4/IPv6 + // address for the hostname as A/AAAA records, and two test TXT records + + // Answer PTR record reverse mapping "<_service-name>._tcp.local." to + // ".<_service-name>._tcp.local." + mdns_record_t answer = service->record_ptr; + + mdns_record_t additional[5] = {0}; + size_t additional_count = 0; + + // SRV record mapping ".<_service-name>._tcp.local." to + // ".local." with port. Set weight & priority to 0. + additional[additional_count++] = service->record_srv; + + // A/AAAA records mapping ".local." to IPv4/IPv6 addresses + if (service->address_ipv4.sin_family == AF_INET) + additional[additional_count++] = service->record_a; + if (service->address_ipv6.sin6_family == AF_INET6) + additional[additional_count++] = service->record_aaaa; + + // Add two test TXT records for our service instance name, will be coalesced into + // one record with both key-value pair strings by the library + additional[additional_count++] = service->txt_record[0]; + additional[additional_count++] = service->txt_record[1]; + + // Send the answer, unicast or multicast depending on flag in query + uint16_t unicast = (rclass & MDNS_UNICAST_RESPONSE); + printf(" --> answer %.*s (%s)\n", + MDNS_STRING_FORMAT(service->record_ptr.data.ptr.name), + (unicast ? "unicast" : "multicast")); + + if (unicast) { + mdns_query_answer_unicast(sock, from, addrlen, sendbuffer, sizeof(sendbuffer), + query_id, rtype, name.str, name.length, answer, 0, 0, + additional, additional_count); + } else { + mdns_query_answer_multicast(sock, sendbuffer, sizeof(sendbuffer), answer, 0, 0, + additional, additional_count); + } + } + } else if ((name.length == service->service_instance.length) && + (strncmp(name.str, service->service_instance.str, name.length) == 0)) { + if ((rtype == MDNS_RECORDTYPE_SRV) || (rtype == MDNS_RECORDTYPE_ANY)) { + // The SRV query was for our service instance (usually + // ".<_service-name._tcp.local"), answer a SRV record mapping the service + // instance name to our qualified hostname (typically ".local.") and port, as + // well as any IPv4/IPv6 address for the hostname as A/AAAA records, and two test TXT + // records + + // Answer PTR record reverse mapping "<_service-name>._tcp.local." to + // ".<_service-name>._tcp.local." + mdns_record_t answer = service->record_srv; + + mdns_record_t additional[5] = {0}; + size_t additional_count = 0; + + // A/AAAA records mapping ".local." to IPv4/IPv6 addresses + if (service->address_ipv4.sin_family == AF_INET) + additional[additional_count++] = service->record_a; + if (service->address_ipv6.sin6_family == AF_INET6) + additional[additional_count++] = service->record_aaaa; + + // Add two test TXT records for our service instance name, will be coalesced into + // one record with both key-value pair strings by the library + additional[additional_count++] = service->txt_record[0]; + additional[additional_count++] = service->txt_record[1]; + + // Send the answer, unicast or multicast depending on flag in query + uint16_t unicast = (rclass & MDNS_UNICAST_RESPONSE); + printf(" --> answer %.*s port %d (%s)\n", + MDNS_STRING_FORMAT(service->record_srv.data.srv.name), service->port, + (unicast ? "unicast" : "multicast")); + + if (unicast) { + mdns_query_answer_unicast(sock, from, addrlen, sendbuffer, sizeof(sendbuffer), + query_id, rtype, name.str, name.length, answer, 0, 0, + additional, additional_count); + } else { + mdns_query_answer_multicast(sock, sendbuffer, sizeof(sendbuffer), answer, 0, 0, + additional, additional_count); + } + } + } else if ((name.length == service->hostname_qualified.length) && + (strncmp(name.str, service->hostname_qualified.str, name.length) == 0)) { + if (((rtype == MDNS_RECORDTYPE_A) || (rtype == MDNS_RECORDTYPE_ANY)) && + (service->address_ipv4.sin_family == AF_INET)) { + // The A query was for our qualified hostname (typically ".local.") and we + // have an IPv4 address, answer with an A record mappiing the hostname to an IPv4 + // address, as well as any IPv6 address for the hostname, and two test TXT records + + // Answer A records mapping ".local." to IPv4 address + mdns_record_t answer = service->record_a; + + mdns_record_t additional[5] = {0}; + size_t additional_count = 0; + + // AAAA record mapping ".local." to IPv6 addresses + if (service->address_ipv6.sin6_family == AF_INET6) + additional[additional_count++] = service->record_aaaa; + + // Add two test TXT records for our service instance name, will be coalesced into + // one record with both key-value pair strings by the library + additional[additional_count++] = service->txt_record[0]; + additional[additional_count++] = service->txt_record[1]; + + // Send the answer, unicast or multicast depending on flag in query + uint16_t unicast = (rclass & MDNS_UNICAST_RESPONSE); + mdns_string_t addrstr = ip_address_to_string( + addrbuffer, sizeof(addrbuffer), (struct sockaddr*)&service->record_a.data.a.addr, + sizeof(service->record_a.data.a.addr)); + printf(" --> answer %.*s IPv4 %.*s (%s)\n", MDNS_STRING_FORMAT(service->record_a.name), + MDNS_STRING_FORMAT(addrstr), (unicast ? "unicast" : "multicast")); + + if (unicast) { + mdns_query_answer_unicast(sock, from, addrlen, sendbuffer, sizeof(sendbuffer), + query_id, rtype, name.str, name.length, answer, 0, 0, + additional, additional_count); + } else { + mdns_query_answer_multicast(sock, sendbuffer, sizeof(sendbuffer), answer, 0, 0, + additional, additional_count); + } + } else if (((rtype == MDNS_RECORDTYPE_AAAA) || (rtype == MDNS_RECORDTYPE_ANY)) && + (service->address_ipv6.sin6_family == AF_INET6)) { + // The AAAA query was for our qualified hostname (typically ".local.") and we + // have an IPv6 address, answer with an AAAA record mappiing the hostname to an IPv6 + // address, as well as any IPv4 address for the hostname, and two test TXT records + + // Answer AAAA records mapping ".local." to IPv6 address + mdns_record_t answer = service->record_aaaa; + + mdns_record_t additional[5] = {0}; + size_t additional_count = 0; + + // A record mapping ".local." to IPv4 addresses + if (service->address_ipv4.sin_family == AF_INET) + additional[additional_count++] = service->record_a; + + // Add two test TXT records for our service instance name, will be coalesced into + // one record with both key-value pair strings by the library + additional[additional_count++] = service->txt_record[0]; + additional[additional_count++] = service->txt_record[1]; + + // Send the answer, unicast or multicast depending on flag in query + uint16_t unicast = (rclass & MDNS_UNICAST_RESPONSE); + mdns_string_t addrstr = + ip_address_to_string(addrbuffer, sizeof(addrbuffer), + (struct sockaddr*)&service->record_aaaa.data.aaaa.addr, + sizeof(service->record_aaaa.data.aaaa.addr)); + printf(" --> answer %.*s IPv6 %.*s (%s)\n", + MDNS_STRING_FORMAT(service->record_aaaa.name), MDNS_STRING_FORMAT(addrstr), + (unicast ? "unicast" : "multicast")); + + if (unicast) { + mdns_query_answer_unicast(sock, from, addrlen, sendbuffer, sizeof(sendbuffer), + query_id, rtype, name.str, name.length, answer, 0, 0, + additional, additional_count); + } else { + mdns_query_answer_multicast(sock, sendbuffer, sizeof(sendbuffer), answer, 0, 0, + additional, additional_count); + } + } + } + return 0; +} + +// Callback handling questions and answers dump +static int +dump_callback(int sock, const struct sockaddr* from, size_t addrlen, mdns_entry_type_t entry, + uint16_t query_id, uint16_t rtype, uint16_t rclass, uint32_t ttl, const void* data, + size_t size, size_t name_offset, size_t name_length, size_t record_offset, + size_t record_length, void* user_data) { + mdns_string_t fromaddrstr = ip_address_to_string(addrbuffer, sizeof(addrbuffer), from, addrlen); + + size_t offset = name_offset; + mdns_string_t name = mdns_string_extract(data, size, &offset, namebuffer, sizeof(namebuffer)); + + const char* record_name = 0; + if (rtype == MDNS_RECORDTYPE_PTR) + record_name = "PTR"; + else if (rtype == MDNS_RECORDTYPE_SRV) + record_name = "SRV"; + else if (rtype == MDNS_RECORDTYPE_A) + record_name = "A"; + else if (rtype == MDNS_RECORDTYPE_AAAA) + record_name = "AAAA"; + else if (rtype == MDNS_RECORDTYPE_TXT) + record_name = "TXT"; + else if (rtype == MDNS_RECORDTYPE_ANY) + record_name = "ANY"; + else + record_name = ""; + + const char* entry_type = "Question"; + if (entry == MDNS_ENTRYTYPE_ANSWER) + entry_type = "Answer"; + else if (entry == MDNS_ENTRYTYPE_AUTHORITY) + entry_type = "Authority"; + else if (entry == MDNS_ENTRYTYPE_ADDITIONAL) + entry_type = "Additional"; + + printf("%.*s: %s %s %.*s rclass 0x%x ttl %u\n", MDNS_STRING_FORMAT(fromaddrstr), entry_type, + record_name, MDNS_STRING_FORMAT(name), (unsigned int)rclass, ttl); + + return 0; +} + +// Open sockets for sending one-shot multicast queries from an ephemeral port +int +open_client_sockets(int* sockets, int max_sockets, int port) { + // When sending, each socket can only send to one network interface + // Thus we need to open one socket for each interface and address family + int num_sockets = 0; + +#ifdef _WIN32 + + IP_ADAPTER_ADDRESSES* adapter_address = 0; + ULONG address_size = 8000; + unsigned int ret; + unsigned int num_retries = 4; + do { + adapter_address = (IP_ADAPTER_ADDRESSES*)malloc(address_size); + ret = GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_ANYCAST, 0, + adapter_address, &address_size); + if (ret == ERROR_BUFFER_OVERFLOW) { + free(adapter_address); + adapter_address = 0; + address_size *= 2; + } else { + break; + } + } while (num_retries-- > 0); + + if (!adapter_address || (ret != NO_ERROR)) { + free(adapter_address); + printf("Failed to get network adapter addresses\n"); + return num_sockets; + } + + int first_ipv4 = 1; + int first_ipv6 = 1; + for (PIP_ADAPTER_ADDRESSES adapter = adapter_address; adapter; adapter = adapter->Next) { + if (adapter->TunnelType == TUNNEL_TYPE_TEREDO) + continue; + if (adapter->OperStatus != IfOperStatusUp) + continue; + + for (IP_ADAPTER_UNICAST_ADDRESS* unicast = adapter->FirstUnicastAddress; unicast; + unicast = unicast->Next) { + if (unicast->Address.lpSockaddr->sa_family == AF_INET) { + struct sockaddr_in* saddr = (struct sockaddr_in*)unicast->Address.lpSockaddr; + if ((saddr->sin_addr.S_un.S_un_b.s_b1 != 127) || + (saddr->sin_addr.S_un.S_un_b.s_b2 != 0) || + (saddr->sin_addr.S_un.S_un_b.s_b3 != 0) || + (saddr->sin_addr.S_un.S_un_b.s_b4 != 1)) { + int log_addr = 0; + if (first_ipv4) { + service_address_ipv4 = *saddr; + first_ipv4 = 0; + log_addr = 1; + } + has_ipv4 = 1; + if (num_sockets < max_sockets) { + saddr->sin_port = htons((unsigned short)port); + int sock = mdns_socket_open_ipv4(saddr); + if (sock >= 0) { + sockets[num_sockets++] = sock; + log_addr = 1; + } else { + log_addr = 0; + } + } + if (log_addr) { + char buffer[128]; + mdns_string_t addr = ipv4_address_to_string(buffer, sizeof(buffer), saddr, + sizeof(struct sockaddr_in)); + printf("Local IPv4 address: %.*s\n", MDNS_STRING_FORMAT(addr)); + } + } + } else if (unicast->Address.lpSockaddr->sa_family == AF_INET6) { + struct sockaddr_in6* saddr = (struct sockaddr_in6*)unicast->Address.lpSockaddr; + // Ignore link-local addresses + if (saddr->sin6_scope_id) + continue; + static const unsigned char localhost[] = {0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1}; + static const unsigned char localhost_mapped[] = {0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0xff, 0xff, 0x7f, 0, 0, 1}; + if ((unicast->DadState == NldsPreferred) && + memcmp(saddr->sin6_addr.s6_addr, localhost, 16) && + memcmp(saddr->sin6_addr.s6_addr, localhost_mapped, 16)) { + int log_addr = 0; + if (first_ipv6) { + service_address_ipv6 = *saddr; + first_ipv6 = 0; + log_addr = 1; + } + has_ipv6 = 1; + if (num_sockets < max_sockets) { + saddr->sin6_port = htons((unsigned short)port); + int sock = mdns_socket_open_ipv6(saddr); + if (sock >= 0) { + sockets[num_sockets++] = sock; + log_addr = 1; + } else { + log_addr = 0; + } + } + if (log_addr) { + char buffer[128]; + mdns_string_t addr = ipv6_address_to_string(buffer, sizeof(buffer), saddr, + sizeof(struct sockaddr_in6)); + printf("Local IPv6 address: %.*s\n", MDNS_STRING_FORMAT(addr)); + } + } + } + } + } + + free(adapter_address); + +#else + + struct ifaddrs* ifaddr = 0; + struct ifaddrs* ifa = 0; + + if (getifaddrs(&ifaddr) < 0) + printf("Unable to get interface addresses\n"); + + int first_ipv4 = 1; + int first_ipv6 = 1; + for (ifa = ifaddr; ifa; ifa = ifa->ifa_next) { + if (!ifa->ifa_addr) + continue; + if (!(ifa->ifa_flags & IFF_UP) || !(ifa->ifa_flags & IFF_MULTICAST)) + continue; + if ((ifa->ifa_flags & IFF_LOOPBACK) || (ifa->ifa_flags & IFF_POINTOPOINT)) + continue; + + if (ifa->ifa_addr->sa_family == AF_INET) { + struct sockaddr_in* saddr = (struct sockaddr_in*)ifa->ifa_addr; + if (saddr->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) { + int log_addr = 0; + if (first_ipv4) { + service_address_ipv4 = *saddr; + first_ipv4 = 0; + log_addr = 1; + } + has_ipv4 = 1; + if (num_sockets < max_sockets) { + saddr->sin_port = htons(port); + int sock = mdns_socket_open_ipv4(saddr); + if (sock >= 0) { + sockets[num_sockets++] = sock; + log_addr = 1; + } else { + log_addr = 0; + } + } + if (log_addr) { + char buffer[128]; + mdns_string_t addr = ipv4_address_to_string(buffer, sizeof(buffer), saddr, + sizeof(struct sockaddr_in)); + printf("Local IPv4 address: %.*s\n", MDNS_STRING_FORMAT(addr)); + } + } + } else if (ifa->ifa_addr->sa_family == AF_INET6) { + struct sockaddr_in6* saddr = (struct sockaddr_in6*)ifa->ifa_addr; + // Ignore link-local addresses + if (saddr->sin6_scope_id) + continue; + static const unsigned char localhost[] = {0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1}; + static const unsigned char localhost_mapped[] = {0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0xff, 0xff, 0x7f, 0, 0, 1}; + if (memcmp(saddr->sin6_addr.s6_addr, localhost, 16) && + memcmp(saddr->sin6_addr.s6_addr, localhost_mapped, 16)) { + int log_addr = 0; + if (first_ipv6) { + service_address_ipv6 = *saddr; + first_ipv6 = 0; + log_addr = 1; + } + has_ipv6 = 1; + if (num_sockets < max_sockets) { + saddr->sin6_port = htons(port); + int sock = mdns_socket_open_ipv6(saddr); + if (sock >= 0) { + sockets[num_sockets++] = sock; + log_addr = 1; + } else { + log_addr = 0; + } + } + if (log_addr) { + char buffer[128]; + mdns_string_t addr = ipv6_address_to_string(buffer, sizeof(buffer), saddr, + sizeof(struct sockaddr_in6)); + printf("Local IPv6 address: %.*s\n", MDNS_STRING_FORMAT(addr)); + } + } + } + } + + freeifaddrs(ifaddr); + +#endif + + return num_sockets; +} + +// Open sockets to listen to incoming mDNS queries on port 5353 +static int +open_service_sockets(int* sockets, int max_sockets) { + // When recieving, each socket can recieve data from all network interfaces + // Thus we only need to open one socket for each address family + int num_sockets = 0; + + // Call the client socket function to enumerate and get local addresses, + // but not open the actual sockets + open_client_sockets(0, 0, 0); + + if (num_sockets < max_sockets) { + struct sockaddr_in sock_addr; + memset(&sock_addr, 0, sizeof(struct sockaddr_in)); + sock_addr.sin_family = AF_INET; +#ifdef _WIN32 + sock_addr.sin_addr = in4addr_any; +#else + sock_addr.sin_addr.s_addr = INADDR_ANY; +#endif + sock_addr.sin_port = htons(MDNS_PORT); +#ifdef __APPLE__ + sock_addr.sin_len = sizeof(struct sockaddr_in); +#endif + int sock = mdns_socket_open_ipv4(&sock_addr); + if (sock >= 0) + sockets[num_sockets++] = sock; + } + + if (num_sockets < max_sockets) { + struct sockaddr_in6 sock_addr; + memset(&sock_addr, 0, sizeof(struct sockaddr_in6)); + sock_addr.sin6_family = AF_INET6; + sock_addr.sin6_addr = in6addr_any; + sock_addr.sin6_port = htons(MDNS_PORT); +#ifdef __APPLE__ + sock_addr.sin6_len = sizeof(struct sockaddr_in6); +#endif + int sock = mdns_socket_open_ipv6(&sock_addr); + if (sock >= 0) + sockets[num_sockets++] = sock; + } + + return num_sockets; +} + +// Send a DNS-SD query +int +send_dns_sd(void) { + int sockets[32]; + int num_sockets = open_client_sockets(sockets, sizeof(sockets) / sizeof(sockets[0]), 0); + if (num_sockets <= 0) { + printf("Failed to open any client sockets\n"); + return -1; + } + printf("Opened %d socket%s for DNS-SD\n", num_sockets, num_sockets > 1 ? "s" : ""); + + printf("Sending DNS-SD discovery\n"); + for (int isock = 0; isock < num_sockets; ++isock) { + if (mdns_discovery_send(sockets[isock])) + printf("Failed to send DNS-DS discovery: %s\n", strerror(errno)); + } + + size_t capacity = 2048; + void* buffer = malloc(capacity); + void* user_data = 0; + size_t records; + + // This is a simple implementation that loops for 5 seconds or as long as we get replies + int res; + printf("Reading DNS-SD replies\n"); + do { + struct timeval timeout; + timeout.tv_sec = 5; + timeout.tv_usec = 0; + + int nfds = 0; + fd_set readfs; + FD_ZERO(&readfs); + for (int isock = 0; isock < num_sockets; ++isock) { + if (sockets[isock] >= nfds) + nfds = sockets[isock] + 1; + FD_SET(sockets[isock], &readfs); + } + + records = 0; + res = select(nfds, &readfs, 0, 0, &timeout); + if (res > 0) { + for (int isock = 0; isock < num_sockets; ++isock) { + if (FD_ISSET(sockets[isock], &readfs)) { + records += mdns_discovery_recv(sockets[isock], buffer, capacity, query_callback, + user_data); + } + } + } + } while (res > 0); + + free(buffer); + + for (int isock = 0; isock < num_sockets; ++isock) + mdns_socket_close(sockets[isock]); + printf("Closed socket%s\n", num_sockets ? "s" : ""); + + return 0; +} + +// Send a mDNS query +static int +send_mdns_query(mdns_query_t* query, size_t count) { + int sockets[32]; + int query_id[32]; + int num_sockets = open_client_sockets(sockets, sizeof(sockets) / sizeof(sockets[0]), 0); + if (num_sockets <= 0) { + printf("Failed to open any client sockets\n"); + return -1; + } + printf("Opened %d socket%s for mDNS query\n", num_sockets, num_sockets ? "s" : ""); + + size_t capacity = 2048; + void* buffer = malloc(capacity); + void* user_data = 0; + + printf("Sending mDNS query"); + for (size_t iq = 0; iq < count; ++iq) { + const char* record_name = "PTR"; + if (query[iq].type == MDNS_RECORDTYPE_SRV) + record_name = "SRV"; + else if (query[iq].type == MDNS_RECORDTYPE_A) + record_name = "A"; + else if (query[iq].type == MDNS_RECORDTYPE_AAAA) + record_name = "AAAA"; + else + query[iq].type = MDNS_RECORDTYPE_PTR; + printf(" : %s %s", query[iq].name, record_name); + } + printf("\n"); + for (int isock = 0; isock < num_sockets; ++isock) { + query_id[isock] = + mdns_multiquery_send(sockets[isock], query, count, buffer, capacity, 0); + if (query_id[isock] < 0) + printf("Failed to send mDNS query: %s\n", strerror(errno)); + } + + // This is a simple implementation that loops for 5 seconds or as long as we get replies + int res; + printf("Reading mDNS query replies\n"); + int records = 0; + do { + struct timeval timeout; + timeout.tv_sec = 10; + timeout.tv_usec = 0; + + int nfds = 0; + fd_set readfs; + FD_ZERO(&readfs); + for (int isock = 0; isock < num_sockets; ++isock) { + if (sockets[isock] >= nfds) + nfds = sockets[isock] + 1; + FD_SET(sockets[isock], &readfs); + } + + res = select(nfds, &readfs, 0, 0, &timeout); + if (res > 0) { + for (int isock = 0; isock < num_sockets; ++isock) { + if (FD_ISSET(sockets[isock], &readfs)) { + int rec = mdns_query_recv(sockets[isock], buffer, capacity, query_callback, + user_data, query_id[isock]); + if (rec > 0) + records += rec; + } + FD_SET(sockets[isock], &readfs); + } + } + } while (res > 0); + + printf("Read %d records\n", records); + + free(buffer); + + for (int isock = 0; isock < num_sockets; ++isock) + mdns_socket_close(sockets[isock]); + printf("Closed socket%s\n", num_sockets ? "s" : ""); + + return 0; +} + +// Provide a mDNS service, answering incoming DNS-SD and mDNS queries +static int +service_mdns(const char* hostname, const char* service_name, int service_port) { + int sockets[32]; + int num_sockets = open_service_sockets(sockets, sizeof(sockets) / sizeof(sockets[0])); + if (num_sockets <= 0) { + printf("Failed to open any client sockets\n"); + return -1; + } + printf("Opened %d socket%s for mDNS service\n", num_sockets, num_sockets ? "s" : ""); + + size_t service_name_length = strlen(service_name); + if (!service_name_length) { + printf("Invalid service name\n"); + return -1; + } + + char* service_name_buffer = malloc(service_name_length + 2); + memcpy(service_name_buffer, service_name, service_name_length); + if (service_name_buffer[service_name_length - 1] != '.') + service_name_buffer[service_name_length++] = '.'; + service_name_buffer[service_name_length] = 0; + service_name = service_name_buffer; + + printf("Service mDNS: %s:%d\n", service_name, service_port); + printf("Hostname: %s\n", hostname); + + size_t capacity = 2048; + void* buffer = malloc(capacity); + + mdns_string_t service_string = (mdns_string_t){service_name, strlen(service_name)}; + mdns_string_t hostname_string = (mdns_string_t){hostname, strlen(hostname)}; + + // Build the service instance ".<_service-name>._tcp.local." string + char service_instance_buffer[256] = {0}; + snprintf(service_instance_buffer, sizeof(service_instance_buffer) - 1, "%.*s.%.*s", + MDNS_STRING_FORMAT(hostname_string), MDNS_STRING_FORMAT(service_string)); + mdns_string_t service_instance_string = + (mdns_string_t){service_instance_buffer, strlen(service_instance_buffer)}; + + // Build the ".local." string + char qualified_hostname_buffer[256] = {0}; + snprintf(qualified_hostname_buffer, sizeof(qualified_hostname_buffer) - 1, "%.*s.local.", + MDNS_STRING_FORMAT(hostname_string)); + mdns_string_t hostname_qualified_string = + (mdns_string_t){qualified_hostname_buffer, strlen(qualified_hostname_buffer)}; + + service_t service = {0}; + service.service = service_string; + service.hostname = hostname_string; + service.service_instance = service_instance_string; + service.hostname_qualified = hostname_qualified_string; + service.address_ipv4 = service_address_ipv4; + service.address_ipv6 = service_address_ipv6; + service.port = service_port; + + // Setup our mDNS records + + // PTR record reverse mapping "<_service-name>._tcp.local." to + // ".<_service-name>._tcp.local." + service.record_ptr = (mdns_record_t){.name = service.service, + .type = MDNS_RECORDTYPE_PTR, + .data.ptr.name = service.service_instance, + .rclass = 0, + .ttl = 0}; + + // SRV record mapping ".<_service-name>._tcp.local." to + // ".local." with port. Set weight & priority to 0. + service.record_srv = (mdns_record_t){.name = service.service_instance, + .type = MDNS_RECORDTYPE_SRV, + .data.srv.name = service.hostname_qualified, + .data.srv.port = service.port, + .data.srv.priority = 0, + .data.srv.weight = 0, + .rclass = 0, + .ttl = 0}; + + // A/AAAA records mapping ".local." to IPv4/IPv6 addresses + service.record_a = (mdns_record_t){.name = service.hostname_qualified, + .type = MDNS_RECORDTYPE_A, + .data.a.addr = service.address_ipv4, + .rclass = 0, + .ttl = 0}; + + service.record_aaaa = (mdns_record_t){.name = service.hostname_qualified, + .type = MDNS_RECORDTYPE_AAAA, + .data.aaaa.addr = service.address_ipv6, + .rclass = 0, + .ttl = 0}; + + // Add two test TXT records for our service instance name, will be coalesced into + // one record with both key-value pair strings by the library + service.txt_record[0] = (mdns_record_t){.name = service.service_instance, + .type = MDNS_RECORDTYPE_TXT, + .data.txt.key = {MDNS_STRING_CONST("test")}, + .data.txt.value = {MDNS_STRING_CONST("1")}, + .rclass = 0, + .ttl = 0}; + service.txt_record[1] = (mdns_record_t){.name = service.service_instance, + .type = MDNS_RECORDTYPE_TXT, + .data.txt.key = {MDNS_STRING_CONST("other")}, + .data.txt.value = {MDNS_STRING_CONST("value")}, + .rclass = 0, + .ttl = 0}; + + // Send an announcement on startup of service + { + printf("Sending announce\n"); + mdns_record_t additional[5] = {0}; + size_t additional_count = 0; + additional[additional_count++] = service.record_srv; + if (service.address_ipv4.sin_family == AF_INET) + additional[additional_count++] = service.record_a; + if (service.address_ipv6.sin6_family == AF_INET6) + additional[additional_count++] = service.record_aaaa; + additional[additional_count++] = service.txt_record[0]; + additional[additional_count++] = service.txt_record[1]; + + for (int isock = 0; isock < num_sockets; ++isock) + mdns_announce_multicast(sockets[isock], buffer, capacity, service.record_ptr, 0, 0, + additional, additional_count); + } + + // This is a crude implementation that checks for incoming queries + while (running) { + int nfds = 0; + fd_set readfs; + FD_ZERO(&readfs); + for (int isock = 0; isock < num_sockets; ++isock) { + if (sockets[isock] >= nfds) + nfds = sockets[isock] + 1; + FD_SET(sockets[isock], &readfs); + } + + struct timeval timeout; + timeout.tv_sec = 0; + timeout.tv_usec = 100000; + + if (select(nfds, &readfs, 0, 0, &timeout) >= 0) { + for (int isock = 0; isock < num_sockets; ++isock) { + if (FD_ISSET(sockets[isock], &readfs)) { + mdns_socket_listen(sockets[isock], buffer, capacity, service_callback, + &service); + } + FD_SET(sockets[isock], &readfs); + } + } else { + break; + } + } + + // Send a goodbye on end of service + { + printf("Sending goodbye\n"); + mdns_record_t additional[5] = {0}; + size_t additional_count = 0; + additional[additional_count++] = service.record_srv; + if (service.address_ipv4.sin_family == AF_INET) + additional[additional_count++] = service.record_a; + if (service.address_ipv6.sin6_family == AF_INET6) + additional[additional_count++] = service.record_aaaa; + additional[additional_count++] = service.txt_record[0]; + additional[additional_count++] = service.txt_record[1]; + + for (int isock = 0; isock < num_sockets; ++isock) + mdns_goodbye_multicast(sockets[isock], buffer, capacity, service.record_ptr, 0, 0, + additional, additional_count); + } + + free(buffer); + free(service_name_buffer); + + for (int isock = 0; isock < num_sockets; ++isock) + mdns_socket_close(sockets[isock]); + printf("Closed socket%s\n", num_sockets ? "s" : ""); + + return 0; +} + + +// Dump all incoming mDNS queries and answers +static int +dump_mdns(void) { + int sockets[32]; + int num_sockets = open_service_sockets(sockets, sizeof(sockets) / sizeof(sockets[0])); + if (num_sockets <= 0) { + printf("Failed to open any client sockets\n"); + return -1; + } + printf("Opened %d socket%s for mDNS dump\n", num_sockets, num_sockets ? "s" : ""); + + size_t capacity = 2048; + void* buffer = malloc(capacity); + + // This is a crude implementation that checks for incoming queries and answers + while (running) { + int nfds = 0; + fd_set readfs; + FD_ZERO(&readfs); + for (int isock = 0; isock < num_sockets; ++isock) { + if (sockets[isock] >= nfds) + nfds = sockets[isock] + 1; + FD_SET(sockets[isock], &readfs); + } + + struct timeval timeout; + timeout.tv_sec = 0; + timeout.tv_usec = 100000; + + if (select(nfds, &readfs, 0, 0, &timeout) >= 0) { + for (int isock = 0; isock < num_sockets; ++isock) { + if (FD_ISSET(sockets[isock], &readfs)) { + mdns_socket_listen(sockets[isock], buffer, capacity, dump_callback, 0); + } + FD_SET(sockets[isock], &readfs); + } + } else { + break; + } + } + + free(buffer); + + for (int isock = 0; isock < num_sockets; ++isock) + mdns_socket_close(sockets[isock]); + printf("Closed socket%s\n", num_sockets ? "s" : ""); + + return 0; +} + +#ifdef MDNS_FUZZING + +#undef printf + +// Fuzzing by piping random data into the recieve functions +static void +fuzz_mdns(void) { +#define MAX_FUZZ_SIZE 4096 +#define MAX_PASSES (1024 * 1024 * 1024) + + static uint8_t fuzz_mdns_services_query[] = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x09, '_', + 's', 'e', 'r', 'v', 'i', 'c', 'e', 's', 0x07, '_', 'd', 'n', 's', '-', + 's', 'd', 0x04, '_', 'u', 'd', 'p', 0x05, 'l', 'o', 'c', 'a', 'l', 0x00}; + + uint8_t* buffer = malloc(MAX_FUZZ_SIZE); + uint8_t* strbuffer = malloc(MAX_FUZZ_SIZE); + for (int ipass = 0; ipass < MAX_PASSES; ++ipass) { + size_t size = rand() % MAX_FUZZ_SIZE; + for (size_t i = 0; i < size; ++i) + buffer[i] = rand() & 0xFF; + + if (ipass % 4) { + // Crafted fuzzing, make sure header is reasonable + memcpy(buffer, fuzz_mdns_services_query, sizeof(fuzz_mdns_services_query)); + uint16_t* header = (uint16_t*)buffer; + header[0] = 0; + header[1] = htons(0x8400); + for (int ival = 2; ival < 6; ++ival) + header[ival] = rand() & 0xFF; + } + mdns_discovery_recv(0, (void*)buffer, size, query_callback, 0); + + mdns_socket_listen(0, (void*)buffer, size, service_callback, 0); + + if (ipass % 4) { + // Crafted fuzzing, make sure header is reasonable (1 question claimed). + // Earlier passes will have done completely random data + uint16_t* header = (uint16_t*)buffer; + header[2] = htons(1); + } + mdns_query_recv(0, (void*)buffer, size, query_callback, 0, 0); + + // Fuzzing by piping random data into the parse functions + size_t offset = size ? (rand() % size) : 0; + size_t length = size ? (rand() % (size - offset)) : 0; + mdns_record_parse_ptr(buffer, size, offset, length, strbuffer, MAX_FUZZ_SIZE); + + offset = size ? (rand() % size) : 0; + length = size ? (rand() % (size - offset)) : 0; + mdns_record_parse_srv(buffer, size, offset, length, strbuffer, MAX_FUZZ_SIZE); + + struct sockaddr_in addr_ipv4; + offset = size ? (rand() % size) : 0; + length = size ? (rand() % (size - offset)) : 0; + mdns_record_parse_a(buffer, size, offset, length, &addr_ipv4); + + struct sockaddr_in6 addr_ipv6; + offset = size ? (rand() % size) : 0; + length = size ? (rand() % (size - offset)) : 0; + mdns_record_parse_aaaa(buffer, size, offset, length, &addr_ipv6); + + offset = size ? (rand() % size) : 0; + length = size ? (rand() % (size - offset)) : 0; + mdns_record_parse_txt(buffer, size, offset, length, (mdns_record_txt_t*)strbuffer, + MAX_FUZZ_SIZE); + + if (ipass && !(ipass % 10000)) + printf("Completed fuzzing pass %d\n", ipass); + } + + free(buffer); + free(strbuffer); +} + +#endif + +#ifdef _WIN32 +BOOL console_handler(DWORD signal) { + if (signal == CTRL_C_EVENT) { + running = 0; + } + return TRUE; +} +#else +void signal_handler(int signal) { + running = 0; +} +#endif + +int +__main(int argc, const char* const* argv) { + int mode = 0; + const char* service = "_test-mdns._tcp.local."; + const char* hostname = "dummy-host"; + mdns_query_t query[16]; + size_t query_count = 0; + int service_port = 42424; + +#ifdef _WIN32 + + WORD versionWanted = MAKEWORD(1, 1); + WSADATA wsaData; + if (WSAStartup(versionWanted, &wsaData)) { + printf("Failed to initialize WinSock\n"); + return -1; + } + + char hostname_buffer[256]; + DWORD hostname_size = (DWORD)sizeof(hostname_buffer); + if (GetComputerNameA(hostname_buffer, &hostname_size)) + hostname = hostname_buffer; + + SetConsoleCtrlHandler(console_handler, TRUE); +#else + + char hostname_buffer[256]; + size_t hostname_size = sizeof(hostname_buffer); + if (gethostname(hostname_buffer, hostname_size) == 0) + hostname = hostname_buffer; + signal(SIGINT, signal_handler); +#endif + + for (int iarg = 0; iarg < argc; ++iarg) { + if (strcmp(argv[iarg], "--discovery") == 0) { + mode = 0; + } else if (strcmp(argv[iarg], "--query") == 0) { + // Each query is either a service name, or a pair of record type and a service name + // For example: + // mdns --query _foo._tcp.local. + // mdns --query SRV myhost._foo._tcp.local. + // mdns --query A myhost._tcp.local. _service._tcp.local. + mode = 1; + ++iarg; + while ((iarg < argc) && (query_count < 16)) { + query[query_count].name = argv[iarg++]; + query[query_count].type = MDNS_RECORDTYPE_PTR; + if (iarg < argc) { + mdns_record_type_t record_type = 0; + if (strcmp(query[query_count].name, "PTR") == 0) + record_type = MDNS_RECORDTYPE_PTR; + else if (strcmp(query[query_count].name, "SRV") == 0) + record_type = MDNS_RECORDTYPE_SRV; + else if (strcmp(query[query_count].name, "A") == 0) + record_type = MDNS_RECORDTYPE_A; + else if (strcmp(query[query_count].name, "AAAA") == 0) + record_type = MDNS_RECORDTYPE_AAAA; + if (record_type != 0) { + query[query_count].type = record_type; + query[query_count].name = argv[iarg++]; + } + } + query[query_count].length = strlen(query[query_count].name); + ++query_count; + } + } else if (strcmp(argv[iarg], "--service") == 0) { + mode = 2; + ++iarg; + if (iarg < argc) + service = argv[iarg]; + } else if (strcmp(argv[iarg], "--dump") == 0) { + mode = 3; + } else if (strcmp(argv[iarg], "--hostname") == 0) { + ++iarg; + if (iarg < argc) + hostname = argv[iarg]; + } else if (strcmp(argv[iarg], "--port") == 0) { + ++iarg; + if (iarg < argc) + service_port = atoi(argv[iarg]); + } + } + +#ifdef MDNS_FUZZING + fuzz_mdns(); +#else + int ret; + if (mode == 0) + ret = send_dns_sd(); + else if (mode == 1) + ret = send_mdns_query(query, query_count); + else if (mode == 2) + ret = service_mdns(hostname, service, service_port); + else if (mode == 3) + ret = dump_mdns(); +#endif + +#ifdef _WIN32 + WSACleanup(); +#endif + + return 0; +} diff --git a/src/slic3r/Utils/mdns/mdns.h b/src/slic3r/Utils/mdns/mdns.h new file mode 100644 index 0000000000..c32fd7f505 --- /dev/null +++ b/src/slic3r/Utils/mdns/mdns.h @@ -0,0 +1,1641 @@ +/* mdns.h - mDNS/DNS-SD library - Public Domain - 2017 Mattias Jansson + * + * This library provides a cross-platform mDNS and DNS-SD library in C. + * The implementation is based on RFC 6762 and RFC 6763. + * + * The latest source code is always available at + * + * https://github.com/mjansson/mdns + * + * This library is put in the public domain; you can redistribute it and/or modify it without any + * restrictions. + * + */ + +#pragma once + +#include +#include +#include +#include + +#include +#ifdef _WIN32 +#include +#include +#define strncasecmp _strnicmp +#else +#include +#include +#include +#endif + +#ifdef __cplusplus +extern "C" { +#endif + +#define MDNS_INVALID_POS ((size_t)-1) + +#define MDNS_STRING_CONST(s) (s), (sizeof((s)) - 1) +#define MDNS_STRING_ARGS(s) s.str, s.length +#define MDNS_STRING_FORMAT(s) (int)((s).length), s.str + +#define MDNS_POINTER_OFFSET(p, ofs) ((void*)((char*)(p) + (ptrdiff_t)(ofs))) +#define MDNS_POINTER_OFFSET_CONST(p, ofs) ((const void*)((const char*)(p) + (ptrdiff_t)(ofs))) +#define MDNS_POINTER_DIFF(a, b) ((size_t)((const char*)(a) - (const char*)(b))) + +#define MDNS_PORT 5353 +#define MDNS_UNICAST_RESPONSE 0x8000U +#define MDNS_CACHE_FLUSH 0x8000U +#define MDNS_MAX_SUBSTRINGS 64 + +enum mdns_record_type { + MDNS_RECORDTYPE_IGNORE = 0, + // Address + MDNS_RECORDTYPE_A = 1, + // Domain Name pointer + MDNS_RECORDTYPE_PTR = 12, + // Arbitrary text string + MDNS_RECORDTYPE_TXT = 16, + // IP6 Address [Thomson] + MDNS_RECORDTYPE_AAAA = 28, + // Server Selection [RFC2782] + MDNS_RECORDTYPE_SRV = 33, + // Any available records + MDNS_RECORDTYPE_ANY = 255 +}; + +enum mdns_entry_type { + MDNS_ENTRYTYPE_QUESTION = 0, + MDNS_ENTRYTYPE_ANSWER = 1, + MDNS_ENTRYTYPE_AUTHORITY = 2, + MDNS_ENTRYTYPE_ADDITIONAL = 3 +}; + +enum mdns_class { MDNS_CLASS_IN = 1, MDNS_CLASS_ANY = 255 }; + +typedef enum mdns_record_type mdns_record_type_t; +typedef enum mdns_entry_type mdns_entry_type_t; +typedef enum mdns_class mdns_class_t; + +typedef int (*mdns_record_callback_fn)(int sock, const struct sockaddr* from, size_t addrlen, + mdns_entry_type_t entry, uint16_t query_id, uint16_t rtype, + uint16_t rclass, uint32_t ttl, const void* data, size_t size, + size_t name_offset, size_t name_length, size_t record_offset, + size_t record_length, void* user_data); + +typedef struct mdns_string_t mdns_string_t; +typedef struct mdns_string_pair_t mdns_string_pair_t; +typedef struct mdns_string_table_item_t mdns_string_table_item_t; +typedef struct mdns_string_table_t mdns_string_table_t; +typedef struct mdns_record_t mdns_record_t; +typedef struct mdns_record_srv_t mdns_record_srv_t; +typedef struct mdns_record_ptr_t mdns_record_ptr_t; +typedef struct mdns_record_a_t mdns_record_a_t; +typedef struct mdns_record_aaaa_t mdns_record_aaaa_t; +typedef struct mdns_record_txt_t mdns_record_txt_t; +typedef struct mdns_query_t mdns_query_t; + +#ifdef _WIN32 +typedef int mdns_size_t; +typedef int mdns_ssize_t; +#else +typedef size_t mdns_size_t; +typedef ssize_t mdns_ssize_t; +#endif + +struct mdns_string_t { + const char* str; + size_t length; +}; + +struct mdns_ip_mac_str { + char ip[16] ; + char mac[12]; +}; + +struct mdns_string_pair_t { + size_t offset; + size_t length; + int ref; +}; + +struct mdns_string_table_t { + size_t offset[16]; + size_t count; + size_t next; +}; + +struct mdns_record_srv_t { + uint16_t priority; + uint16_t weight; + uint16_t port; + mdns_string_t name; +}; + +struct mdns_record_ptr_t { + mdns_string_t name; +}; + +struct mdns_record_a_t { + struct sockaddr_in addr; +}; + +struct mdns_record_aaaa_t { + struct sockaddr_in6 addr; +}; + +struct mdns_record_txt_t { + mdns_string_t key; + mdns_string_t value; +}; + +struct mdns_record_t { + mdns_string_t name; + mdns_record_type_t type; + union mdns_record_data { + mdns_record_ptr_t ptr; + mdns_record_srv_t srv; + mdns_record_a_t a; + mdns_record_aaaa_t aaaa; + mdns_record_txt_t txt; + } data; + uint16_t rclass; + uint32_t ttl; +}; + +struct mdns_header_t { + uint16_t query_id; + uint16_t flags; + uint16_t questions; + uint16_t answer_rrs; + uint16_t authority_rrs; + uint16_t additional_rrs; +}; + +struct mdns_query_t { + mdns_record_type_t type; + const char* name; + size_t length; +}; + +void discoveryServiceC(); + +// mDNS/DNS-SD public API + +//! Open and setup a IPv4 socket for mDNS/DNS-SD. To bind the socket to a specific interface, pass +//! in the appropriate socket address in saddr, otherwise pass a null pointer for INADDR_ANY. To +//! send one-shot discovery requests and queries pass a null pointer or set 0 as port to assign a +//! random user level ephemeral port. To run discovery service listening for incoming discoveries +//! and queries, you must set MDNS_PORT as port. +static inline int +mdns_socket_open_ipv4(const struct sockaddr_in* saddr); + +//! Setup an already opened IPv4 socket for mDNS/DNS-SD. To bind the socket to a specific interface, +//! pass in the appropriate socket address in saddr, otherwise pass a null pointer for INADDR_ANY. +//! To send one-shot discovery requests and queries pass a null pointer or set 0 as port to assign a +//! random user level ephemeral port. To run discovery service listening for incoming discoveries +//! and queries, you must set MDNS_PORT as port. +static inline int +mdns_socket_setup_ipv4(int sock, const struct sockaddr_in* saddr); + +//! Open and setup a IPv6 socket for mDNS/DNS-SD. To bind the socket to a specific interface, pass +//! in the appropriate socket address in saddr, otherwise pass a null pointer for in6addr_any. To +//! send one-shot discovery requests and queries pass a null pointer or set 0 as port to assign a +//! random user level ephemeral port. To run discovery service listening for incoming discoveries +//! and queries, you must set MDNS_PORT as port. +static inline int +mdns_socket_open_ipv6(const struct sockaddr_in6* saddr); + +//! Setup an already opened IPv6 socket for mDNS/DNS-SD. To bind the socket to a specific interface, +//! pass in the appropriate socket address in saddr, otherwise pass a null pointer for in6addr_any. +//! To send one-shot discovery requests and queries pass a null pointer or set 0 as port to assign a +//! random user level ephemeral port. To run discovery service listening for incoming discoveries +//! and queries, you must set MDNS_PORT as port. +static inline int +mdns_socket_setup_ipv6(int sock, const struct sockaddr_in6* saddr); + +//! Close a socket opened with mdns_socket_open_ipv4 and mdns_socket_open_ipv6. +static inline void +mdns_socket_close(int sock); + +//! Listen for incoming multicast DNS-SD and mDNS query requests. The socket should have been opened +//! on port MDNS_PORT using one of the mdns open or setup socket functions. Buffer must be 32 bit +//! aligned. Parsing is stopped when callback function returns non-zero. Returns the number of +//! queries parsed. +static inline size_t +mdns_socket_listen(int sock, void* buffer, size_t capacity, mdns_record_callback_fn callback, + void* user_data); + +//! Send a multicast DNS-SD reqeuest on the given socket to discover available services. Returns 0 +//! on success, or <0 if error. +static inline int +mdns_discovery_send(int sock); + +//! Recieve unicast responses to a DNS-SD sent with mdns_discovery_send. Any data will be piped to +//! the given callback for parsing. Buffer must be 32 bit aligned. Parsing is stopped when callback +//! function returns non-zero. Returns the number of responses parsed. +static inline size_t +mdns_discovery_recv(int sock, void* buffer, size_t capacity, mdns_record_callback_fn callback, + void* user_data); + + +//! Send a multicast mDNS query on the given socket for the given service name. The supplied buffer +//! will be used to build the query packet and must be 32 bit aligned. The query ID can be set to +//! non-zero to filter responses, however the RFC states that the query ID SHOULD be set to 0 for +//! multicast queries. The query will request a unicast response if the socket is bound to an +//! ephemeral port, or a multicast response if the socket is bound to mDNS port 5353. Returns the +//! used query ID, or <0 if error. +static inline int +mdns_query_send(int sock, mdns_record_type_t type, const char* name, size_t length, void* buffer, + size_t capacity, uint16_t query_id); + +//! Send a multicast mDNS query on the given socket for the given service names. The supplied buffer +//! will be used to build the query packet and must be 32 bit aligned. The query ID can be set to +//! non-zero to filter responses, however the RFC states that the query ID SHOULD be set to 0 for +//! multicast queries. Each additional service name query consists of a triplet - a record type +//! (mdns_record_type_t), a name string pointer (const char*) and a name length (size_t). The list +//! of variable arguments should be terminated with a record type of 0. The query will request a +//! unicast response if the socket is bound to an ephemeral port, or a multicast response if the +//! socket is bound to mDNS port 5353. Returns the used query ID, or <0 if error. +static inline int +mdns_multiquery_send(int sock, const mdns_query_t* query, size_t count, void* buffer, + size_t capacity, uint16_t query_id); + +//! Receive unicast responses to a mDNS query sent with mdns_discovery_recv, optionally filtering +//! out any responses not matching the given query ID. Set the query ID to 0 to parse all responses, +//! even if it is not matching the query ID set in a specific query. Any data will be piped to the +//! given callback for parsing. Buffer must be 32 bit aligned. Parsing is stopped when callback +//! function returns non-zero. Returns the number of responses parsed. +static inline size_t +mdns_query_recv(int sock, void* buffer, size_t capacity, mdns_record_callback_fn callback, + void* user_data, int query_id); + +//! Send a variable unicast mDNS query answer to any question with variable number of records to the +//! given address. Use the top bit of the query class field (MDNS_UNICAST_RESPONSE) in the query +//! recieved to determine if the answer should be sent unicast (bit set) or multicast (bit not set). +//! Buffer must be 32 bit aligned. The record type and name should match the data from the query +//! recieved. Returns 0 if success, or <0 if error. +static inline int +mdns_query_answer_unicast(int sock, const void* address, size_t address_size, void* buffer, + size_t capacity, uint16_t query_id, mdns_record_type_t record_type, + const char* name, size_t name_length, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count); + +//! Send a variable multicast mDNS query answer to any question with variable number of records. Use +//! the top bit of the query class field (MDNS_UNICAST_RESPONSE) in the query recieved to determine +//! if the answer should be sent unicast (bit set) or multicast (bit not set). Buffer must be 32 bit +//! aligned. Returns 0 if success, or <0 if error. +static inline int +mdns_query_answer_multicast(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count); + +//! Send a variable multicast mDNS announcement (as an unsolicited answer) with variable number of +//! records.Buffer must be 32 bit aligned. Returns 0 if success, or <0 if error. Use this on service +//! startup to announce your instance to the local network. +static inline int +mdns_announce_multicast(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count); + +//! Send a variable multicast mDNS announcement. Use this on service end for removing the resource +//! from the local network. The records must be identical to the according announcement. +static inline int +mdns_goodbye_multicast(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count); + +// Parse records functions + +//! Parse a PTR record, returns the name in the record +static inline mdns_string_t +mdns_record_parse_ptr(const void* buffer, size_t size, size_t offset, size_t length, + char* strbuffer, size_t capacity); + +//! Parse a SRV record, returns the priority, weight, port and name in the record +static inline mdns_record_srv_t +mdns_record_parse_srv(const void* buffer, size_t size, size_t offset, size_t length, + char* strbuffer, size_t capacity); + +//! Parse an A record, returns the IPv4 address in the record +static inline struct sockaddr_in* +mdns_record_parse_a(const void* buffer, size_t size, size_t offset, size_t length, + struct sockaddr_in* addr); + +//! Parse an AAAA record, returns the IPv6 address in the record +static inline struct sockaddr_in6* +mdns_record_parse_aaaa(const void* buffer, size_t size, size_t offset, size_t length, + struct sockaddr_in6* addr); + +//! Parse a TXT record, returns the number of key=value records parsed and stores the key-value +//! pairs in the supplied buffer +static inline size_t +mdns_record_parse_txt(const void* buffer, size_t size, size_t offset, size_t length, + mdns_record_txt_t* records, size_t capacity); + +// Internal functions + +static inline mdns_string_t +mdns_string_extract(const void* buffer, size_t size, size_t* offset, char* str, size_t capacity); + +static inline int +mdns_string_skip(const void* buffer, size_t size, size_t* offset); + +static inline size_t +mdns_string_find(const char* str, size_t length, char c, size_t offset); + +//! Compare if two strings are equal. If the strings are equal it returns >0 and the offset variables are +//! updated to the end of the corresponding strings. If the strings are not equal it returns 0 and +//! the offset variables are NOT updated. +static inline int +mdns_string_equal(const void* buffer_lhs, size_t size_lhs, size_t* ofs_lhs, const void* buffer_rhs, + size_t size_rhs, size_t* ofs_rhs); + +static inline void* +mdns_string_make(void* buffer, size_t capacity, void* data, const char* name, size_t length, + mdns_string_table_t* string_table); + +static inline size_t +mdns_string_table_find(mdns_string_table_t* string_table, const void* buffer, size_t capacity, + const char* str, size_t first_length, size_t total_length); + +// Implementations + +static inline uint16_t +mdns_ntohs(const void* data) { + uint16_t aligned; + memcpy(&aligned, data, sizeof(uint16_t)); + return ntohs(aligned); +} + +static inline uint32_t +mdns_ntohl(const void* data) { + uint32_t aligned; + memcpy(&aligned, data, sizeof(uint32_t)); + return ntohl(aligned); +} + +static inline void* +mdns_htons(void* data, uint16_t val) { + val = htons(val); + memcpy(data, &val, sizeof(uint16_t)); + return MDNS_POINTER_OFFSET(data, sizeof(uint16_t)); +} + +static inline void* +mdns_htonl(void* data, uint32_t val) { + val = htonl(val); + memcpy(data, &val, sizeof(uint32_t)); + return MDNS_POINTER_OFFSET(data, sizeof(uint32_t)); +} + +static inline int +mdns_socket_open_ipv4(const struct sockaddr_in* saddr) { + int sock = (int)socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); + if (sock < 0) + return -1; + if (mdns_socket_setup_ipv4(sock, saddr)) { + mdns_socket_close(sock); + return -1; + } + return sock; +} +//==========================add +int +send_dns_sd(void); +int +open_client_sockets(int* sockets, int max_sockets, int port); + +mdns_string_t +ipv4_address_to_string(char* buffer, size_t capacity, const struct sockaddr_in* addr, + size_t addrlen); +mdns_string_t +ip_address_to_string(char* buffer, size_t capacity, const struct sockaddr* addr, size_t addrlen); + +int +query_callback(int sock, const struct sockaddr* from, size_t addrlen, mdns_entry_type_t entry, + uint16_t query_id, uint16_t rtype, uint16_t rclass, uint32_t ttl, const void* data, + size_t size, size_t name_offset, size_t name_length, size_t record_offset, + size_t record_length, void* user_data); + + +static inline int +mdns_socket_setup_ipv4(int sock, const struct sockaddr_in* saddr) { + unsigned char ttl = 1; + unsigned char loopback = 1; + unsigned int reuseaddr = 1; + struct ip_mreq req; + + setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuseaddr, sizeof(reuseaddr)); +#ifdef SO_REUSEPORT + setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const char*)&reuseaddr, sizeof(reuseaddr)); +#endif + setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, (const char*)&ttl, sizeof(ttl)); + setsockopt(sock, IPPROTO_IP, IP_MULTICAST_LOOP, (const char*)&loopback, sizeof(loopback)); + + memset(&req, 0, sizeof(req)); + req.imr_multiaddr.s_addr = htonl((((uint32_t)224U) << 24U) | ((uint32_t)251U)); + if (saddr) + req.imr_interface = saddr->sin_addr; + if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&req, sizeof(req))) + return -1; + + struct sockaddr_in sock_addr; + if (!saddr) { + memset(&sock_addr, 0, sizeof(struct sockaddr_in)); + sock_addr.sin_family = AF_INET; + sock_addr.sin_addr.s_addr = INADDR_ANY; +#ifdef __APPLE__ + sock_addr.sin_len = sizeof(struct sockaddr_in); +#endif + } else { + memcpy(&sock_addr, saddr, sizeof(struct sockaddr_in)); + setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF, (const char*)&sock_addr.sin_addr, + sizeof(sock_addr.sin_addr)); +#ifndef _WIN32 + sock_addr.sin_addr.s_addr = INADDR_ANY; +#endif + } + + if (bind(sock, (struct sockaddr*)&sock_addr, sizeof(struct sockaddr_in))) + return -1; + +#ifdef _WIN32 + unsigned long param = 1; + ioctlsocket(sock, FIONBIO, ¶m); +#else + const int flags = fcntl(sock, F_GETFL, 0); + fcntl(sock, F_SETFL, flags | O_NONBLOCK); +#endif + + return 0; +} + +static inline int +mdns_socket_open_ipv6(const struct sockaddr_in6* saddr) { + int sock = (int)socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP); + if (sock < 0) + return -1; + if (mdns_socket_setup_ipv6(sock, saddr)) { + mdns_socket_close(sock); + return -1; + } + return sock; +} + +static inline int +mdns_socket_setup_ipv6(int sock, const struct sockaddr_in6* saddr) { + int hops = 1; + unsigned int loopback = 1; + unsigned int reuseaddr = 1; + struct ipv6_mreq req; + + setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuseaddr, sizeof(reuseaddr)); +#ifdef SO_REUSEPORT + setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const char*)&reuseaddr, sizeof(reuseaddr)); +#endif + setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, (const char*)&hops, sizeof(hops)); + setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, (const char*)&loopback, sizeof(loopback)); + + memset(&req, 0, sizeof(req)); + req.ipv6mr_multiaddr.s6_addr[0] = 0xFF; + req.ipv6mr_multiaddr.s6_addr[1] = 0x02; + req.ipv6mr_multiaddr.s6_addr[15] = 0xFB; + if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, (char*)&req, sizeof(req))) + return -1; + + struct sockaddr_in6 sock_addr; + if (!saddr) { + memset(&sock_addr, 0, sizeof(struct sockaddr_in6)); + sock_addr.sin6_family = AF_INET6; + sock_addr.sin6_addr = in6addr_any; +#ifdef __APPLE__ + sock_addr.sin6_len = sizeof(struct sockaddr_in6); +#endif + } else { + memcpy(&sock_addr, saddr, sizeof(struct sockaddr_in6)); + unsigned int ifindex = 0; + setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_IF, (const char*)&ifindex, sizeof(ifindex)); +#ifndef _WIN32 + sock_addr.sin6_addr = in6addr_any; +#endif + } + + if (bind(sock, (struct sockaddr*)&sock_addr, sizeof(struct sockaddr_in6))) + return -1; + +#ifdef _WIN32 + unsigned long param = 1; + ioctlsocket(sock, FIONBIO, ¶m); +#else + const int flags = fcntl(sock, F_GETFL, 0); + fcntl(sock, F_SETFL, flags | O_NONBLOCK); +#endif + + return 0; +} + +static inline void +mdns_socket_close(int sock) { +#ifdef _WIN32 + closesocket(sock); +#else + close(sock); +#endif +} + +static inline int +mdns_is_string_ref(uint8_t val) { + return (0xC0 == (val & 0xC0)); +} + +static inline mdns_string_pair_t +mdns_get_next_substring(const void* rawdata, size_t size, size_t offset) { + const uint8_t* buffer = (const uint8_t*)rawdata; + mdns_string_pair_t pair = {MDNS_INVALID_POS, 0, 0}; + if (offset >= size) + return pair; + if (!buffer[offset]) { + pair.offset = offset; + return pair; + } + int recursion = 0; + while (mdns_is_string_ref(buffer[offset])) { + if (size < offset + 2) + return pair; + + offset = mdns_ntohs(MDNS_POINTER_OFFSET(buffer, offset)) & 0x3fff; + if (offset >= size) + return pair; + + pair.ref = 1; + if (++recursion > 16) + return pair; + } + + size_t length = (size_t)buffer[offset++]; + if (size < offset + length) + return pair; + + pair.offset = offset; + pair.length = length; + + return pair; +} + +static inline int +mdns_string_skip(const void* buffer, size_t size, size_t* offset) { + size_t cur = *offset; + mdns_string_pair_t substr; + unsigned int counter = 0; + do { + substr = mdns_get_next_substring(buffer, size, cur); + if ((substr.offset == MDNS_INVALID_POS) || (counter++ > MDNS_MAX_SUBSTRINGS)) + return 0; + if (substr.ref) { + *offset = cur + 2; + return 1; + } + cur = substr.offset + substr.length; + } while (substr.length); + + *offset = cur + 1; + return 1; +} + +static inline int +mdns_string_equal(const void* buffer_lhs, size_t size_lhs, size_t* ofs_lhs, const void* buffer_rhs, + size_t size_rhs, size_t* ofs_rhs) { + size_t lhs_cur = *ofs_lhs; + size_t rhs_cur = *ofs_rhs; + size_t lhs_end = MDNS_INVALID_POS; + size_t rhs_end = MDNS_INVALID_POS; + mdns_string_pair_t lhs_substr; + mdns_string_pair_t rhs_substr; + unsigned int counter = 0; + do { + lhs_substr = mdns_get_next_substring(buffer_lhs, size_lhs, lhs_cur); + rhs_substr = mdns_get_next_substring(buffer_rhs, size_rhs, rhs_cur); + if ((lhs_substr.offset == MDNS_INVALID_POS) || (rhs_substr.offset == MDNS_INVALID_POS) || + (counter++ > MDNS_MAX_SUBSTRINGS)) + return 0; + if (lhs_substr.length != rhs_substr.length) + return 0; + if (strncasecmp((const char*)MDNS_POINTER_OFFSET_CONST(buffer_rhs, rhs_substr.offset), + (const char*)MDNS_POINTER_OFFSET_CONST(buffer_lhs, lhs_substr.offset), + rhs_substr.length)) + return 0; + if (lhs_substr.ref && (lhs_end == MDNS_INVALID_POS)) + lhs_end = lhs_cur + 2; + if (rhs_substr.ref && (rhs_end == MDNS_INVALID_POS)) + rhs_end = rhs_cur + 2; + lhs_cur = lhs_substr.offset + lhs_substr.length; + rhs_cur = rhs_substr.offset + rhs_substr.length; + } while (lhs_substr.length); + + if (lhs_end == MDNS_INVALID_POS) + lhs_end = lhs_cur + 1; + *ofs_lhs = lhs_end; + + if (rhs_end == MDNS_INVALID_POS) + rhs_end = rhs_cur + 1; + *ofs_rhs = rhs_end; + + return 1; +} + +static inline mdns_string_t +mdns_string_extract(const void* buffer, size_t size, size_t* offset, char* str, size_t capacity) { + size_t cur = *offset; + size_t end = MDNS_INVALID_POS; + mdns_string_pair_t substr; + mdns_string_t result; + result.str = str; + result.length = 0; + char* dst = str; + unsigned int counter = 0; + size_t remain = capacity; + do { + substr = mdns_get_next_substring(buffer, size, cur); + if ((substr.offset == MDNS_INVALID_POS) || (counter++ > MDNS_MAX_SUBSTRINGS)) + return result; + if (substr.ref && (end == MDNS_INVALID_POS)) + end = cur + 2; + if (substr.length) { + size_t to_copy = (substr.length < remain) ? substr.length : remain; + memcpy(dst, (const char*)buffer + substr.offset, to_copy); + dst += to_copy; + remain -= to_copy; + if (remain) { + *dst++ = '.'; + --remain; + } + } + cur = substr.offset + substr.length; + } while (substr.length); + + if (end == MDNS_INVALID_POS) + end = cur + 1; + *offset = end; + + result.length = capacity - remain; + return result; +} + +static inline size_t +mdns_string_table_find(mdns_string_table_t* string_table, const void* buffer, size_t capacity, + const char* str, size_t first_length, size_t total_length) { + if (!string_table) + return MDNS_INVALID_POS; + + for (size_t istr = 0; istr < string_table->count; ++istr) { + if (string_table->offset[istr] >= capacity) + continue; + size_t offset = 0; + mdns_string_pair_t sub_string = + mdns_get_next_substring(buffer, capacity, string_table->offset[istr]); + if (!sub_string.length || (sub_string.length != first_length)) + continue; + if (memcmp(str, MDNS_POINTER_OFFSET(buffer, sub_string.offset), sub_string.length)) + continue; + + // Initial substring matches, now match all remaining substrings + offset += first_length + 1; + while (offset < total_length) { + size_t dot_pos = mdns_string_find(str, total_length, '.', offset); + if (dot_pos == MDNS_INVALID_POS) + dot_pos = total_length; + size_t current_length = dot_pos - offset; + + sub_string = + mdns_get_next_substring(buffer, capacity, sub_string.offset + sub_string.length); + if (!sub_string.length || (sub_string.length != current_length)) + break; + if (memcmp(str + offset, MDNS_POINTER_OFFSET(buffer, sub_string.offset), + sub_string.length)) + break; + + offset = dot_pos + 1; + } + + // Return reference offset if entire string matches + if (offset >= total_length) + return string_table->offset[istr]; + } + + return MDNS_INVALID_POS; +} + +static inline void +mdns_string_table_add(mdns_string_table_t* string_table, size_t offset) { + if (!string_table) + return; + + string_table->offset[string_table->next] = offset; + + size_t table_capacity = sizeof(string_table->offset) / sizeof(string_table->offset[0]); + if (++string_table->count > table_capacity) + string_table->count = table_capacity; + if (++string_table->next >= table_capacity) + string_table->next = 0; +} + +static inline size_t +mdns_string_find(const char* str, size_t length, char c, size_t offset) { + const void* found; + if (offset >= length) + return MDNS_INVALID_POS; + found = memchr(str + offset, c, length - offset); + if (found) + return (size_t)MDNS_POINTER_DIFF(found, str); + return MDNS_INVALID_POS; +} + +static inline void* +mdns_string_make_ref(void* data, size_t capacity, size_t ref_offset) { + if (capacity < 2) + return 0; + return mdns_htons(data, 0xC000 | (uint16_t)ref_offset); +} + +static inline void* +mdns_string_make(void* buffer, size_t capacity, void* data, const char* name, size_t length, + mdns_string_table_t* string_table) { + size_t last_pos = 0; + size_t remain = capacity - MDNS_POINTER_DIFF(data, buffer); + if (name[length - 1] == '.') + --length; + while (last_pos < length) { + size_t pos = mdns_string_find(name, length, '.', last_pos); + size_t sub_length = ((pos != MDNS_INVALID_POS) ? pos : length) - last_pos; + size_t total_length = length - last_pos; + + size_t ref_offset = + mdns_string_table_find(string_table, buffer, capacity, + (char*)MDNS_POINTER_OFFSET(name, last_pos), sub_length, + total_length); + if (ref_offset != MDNS_INVALID_POS) + return mdns_string_make_ref(data, remain, ref_offset); + + if (remain <= (sub_length + 1)) + return 0; + + *(unsigned char*)data = (unsigned char)sub_length; + memcpy(MDNS_POINTER_OFFSET(data, 1), name + last_pos, sub_length); + mdns_string_table_add(string_table, MDNS_POINTER_DIFF(data, buffer)); + + data = MDNS_POINTER_OFFSET(data, sub_length + 1); + last_pos = ((pos != MDNS_INVALID_POS) ? pos + 1 : length); + remain = capacity - MDNS_POINTER_DIFF(data, buffer); + } + + if (!remain) + return 0; + + *(unsigned char*)data = 0; + return MDNS_POINTER_OFFSET(data, 1); +} + +static inline size_t +mdns_records_parse(int sock, const struct sockaddr* from, size_t addrlen, const void* buffer, + size_t size, size_t* offset, mdns_entry_type_t type, uint16_t query_id, + size_t records, mdns_record_callback_fn callback, void* user_data) { + size_t parsed = 0; + for (size_t i = 0; i < records; ++i) { + size_t name_offset = *offset; + mdns_string_skip(buffer, size, offset); + if (((*offset) + 10) > size) + return parsed; + size_t name_length = (*offset) - name_offset; + const uint16_t* data = (const uint16_t*)MDNS_POINTER_OFFSET(buffer, *offset); + + uint16_t rtype = mdns_ntohs(data++); + uint16_t rclass = mdns_ntohs(data++); + uint32_t ttl = mdns_ntohl(data); + data += 2; + uint16_t length = mdns_ntohs(data++); + + *offset += 10; + + if (length <= (size - (*offset))) { + ++parsed; + if (callback && + callback(sock, from, addrlen, type, query_id, rtype, rclass, ttl, buffer, size, + name_offset, name_length, *offset, length, user_data)) + break; + } + + *offset += length; + } + return parsed; +} + +static inline int +mdns_unicast_send(int sock, const void* address, size_t address_size, const void* buffer, + size_t size) { + if (sendto(sock, (const char*)buffer, (mdns_size_t)size, 0, (const struct sockaddr*)address, + (socklen_t)address_size) < 0) + return -1; + return 0; +} + +static inline int +mdns_multicast_send(int sock, const void* buffer, size_t size) { + struct sockaddr_storage addr_storage; + struct sockaddr_in addr; + struct sockaddr_in6 addr6; + struct sockaddr* saddr = (struct sockaddr*)&addr_storage; + socklen_t saddrlen = sizeof(struct sockaddr_storage); + if (getsockname(sock, saddr, &saddrlen)) + return -1; + if (saddr->sa_family == AF_INET6) { + memset(&addr6, 0, sizeof(addr6)); + addr6.sin6_family = AF_INET6; +#ifdef __APPLE__ + addr6.sin6_len = sizeof(addr6); +#endif + addr6.sin6_addr.s6_addr[0] = 0xFF; + addr6.sin6_addr.s6_addr[1] = 0x02; + addr6.sin6_addr.s6_addr[15] = 0xFB; + addr6.sin6_port = htons((unsigned short)MDNS_PORT); + saddr = (struct sockaddr*)&addr6; + saddrlen = sizeof(addr6); + } else { + memset(&addr, 0, sizeof(addr)); + addr.sin_family = AF_INET; +#ifdef __APPLE__ + addr.sin_len = sizeof(addr); +#endif + addr.sin_addr.s_addr = htonl((((uint32_t)224U) << 24U) | ((uint32_t)251U)); + addr.sin_port = htons((unsigned short)MDNS_PORT); + saddr = (struct sockaddr*)&addr; + saddrlen = sizeof(addr); + } + + if (sendto(sock, (const char*)buffer, (mdns_size_t)size, 0, saddr, saddrlen) < 0) + return -1; + return 0; +} + +static const uint8_t mdns_services_query[] = { + // Query ID + 0x00, 0x00, + // Flags + 0x00, 0x00, + // 1 question + 0x00, 0x01, + // No answer, authority or additional RRs + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + // _services._dns-sd._udp.local. + 0x09, '_', 's', 'e', 'r', 'v', 'i', 'c', 'e', 's', 0x07, '_', 'd', 'n', 's', '-', 's', 'd', + 0x04, '_', 'u', 'd', 'p', 0x05, 'l', 'o', 'c', 'a', 'l', 0x00, + // PTR record + 0x00, MDNS_RECORDTYPE_PTR, + // QU (unicast response) and class IN + 0x80, MDNS_CLASS_IN}; + +static inline int +mdns_discovery_send(int sock) { + return mdns_multicast_send(sock, mdns_services_query, sizeof(mdns_services_query)); +} + + +static inline size_t +mdns_discovery_recv(int sock, void* buffer, size_t capacity, mdns_record_callback_fn callback, + void* user_data) { + struct sockaddr_in6 addr; + struct sockaddr* saddr = (struct sockaddr*)&addr; + socklen_t addrlen = sizeof(addr); + memset(&addr, 0, sizeof(addr)); +#ifdef __APPLE__ + saddr->sa_len = sizeof(addr); +#endif + mdns_ssize_t ret = recvfrom(sock, (char*)buffer, (mdns_size_t)capacity, 0, saddr, &addrlen); + if (ret <= 0) + return 0; + + size_t data_size = (size_t)ret; + size_t records = 0; + const uint16_t* data = (uint16_t*)buffer; + + uint16_t query_id = mdns_ntohs(data++); + uint16_t flags = mdns_ntohs(data++); + uint16_t questions = mdns_ntohs(data++); + uint16_t answer_rrs = mdns_ntohs(data++); + uint16_t authority_rrs = mdns_ntohs(data++); + uint16_t additional_rrs = mdns_ntohs(data++); + + // According to RFC 6762 the query ID MUST match the sent query ID (which is 0 in our case) + if (query_id || (flags != 0x8400)) + return 0; // Not a reply to our question + + // It seems some implementations do not fill the correct questions field, + // so ignore this check for now and only validate answer string + // if (questions != 1) + // return 0; + + int i; + for (i = 0; i < questions; ++i) { + size_t offset = MDNS_POINTER_DIFF(data, buffer); + size_t verify_offset = 12; + // Verify it's our question, _services._dns-sd._udp.local. + if (!mdns_string_equal(buffer, data_size, &offset, mdns_services_query, + sizeof(mdns_services_query), &verify_offset)) + return 0; + data = (const uint16_t*)MDNS_POINTER_OFFSET(buffer, offset); + + uint16_t rtype = mdns_ntohs(data++); + uint16_t rclass = mdns_ntohs(data++); + + // Make sure we get a reply based on our PTR question for class IN + if ((rtype != MDNS_RECORDTYPE_PTR) || ((rclass & 0x7FFF) != MDNS_CLASS_IN)) + return 0; + } + + for (i = 0; i < answer_rrs; ++i) { + size_t offset = MDNS_POINTER_DIFF(data, buffer); + size_t verify_offset = 12; + // Verify it's an answer to our question, _services._dns-sd._udp.local. + size_t name_offset = offset; + int is_answer = mdns_string_equal(buffer, data_size, &offset, mdns_services_query, + sizeof(mdns_services_query), &verify_offset); + if (!is_answer && !mdns_string_skip(buffer, data_size, &offset)) + break; + size_t name_length = offset - name_offset; + if ((offset + 10) > data_size) + return records; + data = (const uint16_t*)MDNS_POINTER_OFFSET(buffer, offset); + + uint16_t rtype = mdns_ntohs(data++); + uint16_t rclass = mdns_ntohs(data++); + uint32_t ttl = mdns_ntohl(data); + data += 2; + uint16_t length = mdns_ntohs(data++); + if (length > (data_size - offset)) + return 0; + + if (is_answer) { + ++records; + offset = MDNS_POINTER_DIFF(data, buffer); + if (callback && + callback(sock, saddr, addrlen, MDNS_ENTRYTYPE_ANSWER, query_id, rtype, rclass, ttl, + buffer, data_size, name_offset, name_length, offset, length, user_data)) + return records; + } + data = (const uint16_t*)MDNS_POINTER_OFFSET_CONST(data, length); + } + + size_t total_records = records; + size_t offset = MDNS_POINTER_DIFF(data, buffer); + records = + mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_AUTHORITY, query_id, authority_rrs, callback, user_data); + total_records += records; + if (records != authority_rrs) + return total_records; + + records = mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_ADDITIONAL, query_id, additional_rrs, callback, + user_data); + total_records += records; + if (records != additional_rrs) + return total_records; + + return total_records; +} + +static inline size_t +mdns_socket_listen(int sock, void* buffer, size_t capacity, mdns_record_callback_fn callback, + void* user_data) { + struct sockaddr_in6 addr; + struct sockaddr* saddr = (struct sockaddr*)&addr; + socklen_t addrlen = sizeof(addr); + memset(&addr, 0, sizeof(addr)); +#ifdef __APPLE__ + saddr->sa_len = sizeof(addr); +#endif + mdns_ssize_t ret = recvfrom(sock, (char*)buffer, (mdns_size_t)capacity, 0, saddr, &addrlen); + if (ret <= 0) + return 0; + + size_t data_size = (size_t)ret; + const uint16_t* data = (const uint16_t*)buffer; + + uint16_t query_id = mdns_ntohs(data++); + uint16_t flags = mdns_ntohs(data++); + uint16_t questions = mdns_ntohs(data++); + uint16_t answer_rrs = mdns_ntohs(data++); + uint16_t authority_rrs = mdns_ntohs(data++); + uint16_t additional_rrs = mdns_ntohs(data++); + + size_t records; + size_t total_records = 0; + for (int iquestion = 0; iquestion < questions; ++iquestion) { + size_t question_offset = MDNS_POINTER_DIFF(data, buffer); + size_t offset = question_offset; + size_t verify_offset = 12; + int dns_sd = 0; + if (mdns_string_equal(buffer, data_size, &offset, mdns_services_query, + sizeof(mdns_services_query), &verify_offset)) { + dns_sd = 1; + } else if (!mdns_string_skip(buffer, data_size, &offset)) { + break; + } + size_t length = offset - question_offset; + data = (const uint16_t*)MDNS_POINTER_OFFSET_CONST(buffer, offset); + + uint16_t rtype = mdns_ntohs(data++); + uint16_t rclass = mdns_ntohs(data++); + uint16_t class_without_flushbit = rclass & ~MDNS_CACHE_FLUSH; + + // Make sure we get a question of class IN or ANY + if (!((class_without_flushbit == MDNS_CLASS_IN) || + (class_without_flushbit == MDNS_CLASS_ANY))) { + break; + } + + if (dns_sd && flags) + continue; + + ++total_records; + if (callback && callback(sock, saddr, addrlen, MDNS_ENTRYTYPE_QUESTION, query_id, rtype, + rclass, 0, buffer, data_size, question_offset, length, + question_offset, length, user_data)) + return total_records; + } + + size_t offset = MDNS_POINTER_DIFF(data, buffer); + records = mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_ANSWER, query_id, answer_rrs, callback, user_data); + total_records += records; + if (records != answer_rrs) + return total_records; + + records = + mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_AUTHORITY, query_id, authority_rrs, callback, user_data); + total_records += records; + if (records != authority_rrs) + return total_records; + + records = mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_ADDITIONAL, query_id, additional_rrs, callback, + user_data); + + return total_records; +} + +static inline int +mdns_query_send(int sock, mdns_record_type_t type, const char* name, size_t length, void* buffer, + size_t capacity, uint16_t query_id) { + mdns_query_t query; + query.type = type; + query.name = name; + query.length = length; + return mdns_multiquery_send(sock, &query, 1, buffer, capacity, query_id); +} + +static inline int +mdns_multiquery_send(int sock, const mdns_query_t* query, size_t count, void* buffer, size_t capacity, + uint16_t query_id) { + if (!count || (capacity < (sizeof(struct mdns_header_t) + (6 * count)))) + return -1; + + // Ask for a unicast response since it's a one-shot query + uint16_t rclass = MDNS_CLASS_IN | MDNS_UNICAST_RESPONSE; + + struct sockaddr_storage addr_storage; + struct sockaddr* saddr = (struct sockaddr*)&addr_storage; + socklen_t saddrlen = sizeof(addr_storage); + if (getsockname(sock, saddr, &saddrlen) == 0) { + if ((saddr->sa_family == AF_INET) && + (ntohs(((struct sockaddr_in*)saddr)->sin_port) == MDNS_PORT)) + rclass &= ~MDNS_UNICAST_RESPONSE; + else if ((saddr->sa_family == AF_INET6) && + (ntohs(((struct sockaddr_in6*)saddr)->sin6_port) == MDNS_PORT)) + rclass &= ~MDNS_UNICAST_RESPONSE; + } + + struct mdns_header_t* header = (struct mdns_header_t*)buffer; + // Query ID + header->query_id = htons((unsigned short)query_id); + // Flags + header->flags = 0; + // Questions + header->questions = htons((unsigned short)count); + // No answer, authority or additional RRs + header->answer_rrs = 0; + header->authority_rrs = 0; + header->additional_rrs = 0; + // Fill in questions + void* data = MDNS_POINTER_OFFSET(buffer, sizeof(struct mdns_header_t)); + for (size_t iq = 0; iq < count; ++iq) { + // Name string + data = mdns_string_make(buffer, capacity, data, query[iq].name, query[iq].length, 0); + if (!data) + return -1; + // Record type + data = mdns_htons(data, query[iq].type); + //! Optional unicast response based on local port, class IN + data = mdns_htons(data, rclass); + } + + size_t tosend = MDNS_POINTER_DIFF(data, buffer); + if (mdns_multicast_send(sock, buffer, (size_t)tosend)) + return -1; + return query_id; +} + +static inline size_t +mdns_query_recv(int sock, void* buffer, size_t capacity, mdns_record_callback_fn callback, + void* user_data, int only_query_id) { + struct sockaddr_in6 addr; + struct sockaddr* saddr = (struct sockaddr*)&addr; + socklen_t addrlen = sizeof(addr); + memset(&addr, 0, sizeof(addr)); +#ifdef __APPLE__ + saddr->sa_len = sizeof(addr); +#endif + mdns_ssize_t ret = recvfrom(sock, (char*)buffer, (mdns_size_t)capacity, 0, saddr, &addrlen); + if (ret <= 0) + return 0; + + size_t data_size = (size_t)ret; + const uint16_t* data = (const uint16_t*)buffer; + + uint16_t query_id = mdns_ntohs(data++); + uint16_t flags = mdns_ntohs(data++); + uint16_t questions = mdns_ntohs(data++); + uint16_t answer_rrs = mdns_ntohs(data++); + uint16_t authority_rrs = mdns_ntohs(data++); + uint16_t additional_rrs = mdns_ntohs(data++); + (void)sizeof(flags); + + if ((only_query_id > 0) && (query_id != only_query_id)) + return 0; // Not a reply to the wanted one-shot query + + if (questions > 1) + return 0; + + // Skip questions part + int i; + for (i = 0; i < questions; ++i) { + size_t offset = MDNS_POINTER_DIFF(data, buffer); + if (!mdns_string_skip(buffer, data_size, &offset)) + return 0; + data = (const uint16_t*)MDNS_POINTER_OFFSET_CONST(buffer, offset); + // Record type and class not used, skip + // uint16_t rtype = mdns_ntohs(data++); + // uint16_t rclass = mdns_ntohs(data++); + data += 2; + } + + size_t records = 0; + size_t total_records = 0; + size_t offset = MDNS_POINTER_DIFF(data, buffer); + records = mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_ANSWER, query_id, answer_rrs, callback, user_data); + total_records += records; + if (records != answer_rrs) + return total_records; + + records = + mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_AUTHORITY, query_id, authority_rrs, callback, user_data); + total_records += records; + if (records != authority_rrs) + return total_records; + + records = mdns_records_parse(sock, saddr, addrlen, buffer, data_size, &offset, + MDNS_ENTRYTYPE_ADDITIONAL, query_id, additional_rrs, callback, + user_data); + total_records += records; + if (records != additional_rrs) + return total_records; + + return total_records; +} + +static inline void* +mdns_answer_add_question_unicast(void* buffer, size_t capacity, void* data, + mdns_record_type_t record_type, const char* name, + size_t name_length, mdns_string_table_t* string_table) { + data = mdns_string_make(buffer, capacity, data, name, name_length, string_table); + if (!data) + return 0; + size_t remain = capacity - MDNS_POINTER_DIFF(data, buffer); + if (remain < 4) + return 0; + + data = mdns_htons(data, record_type); + data = mdns_htons(data, MDNS_UNICAST_RESPONSE | MDNS_CLASS_IN); + + return data; +} + +static inline void* +mdns_answer_add_record_header(void* buffer, size_t capacity, void* data, mdns_record_t record, + mdns_string_table_t* string_table) { + data = mdns_string_make(buffer, capacity, data, record.name.str, record.name.length, string_table); + if (!data) + return 0; + size_t remain = capacity - MDNS_POINTER_DIFF(data, buffer); + if (remain < 10) + return 0; + + data = mdns_htons(data, record.type); + data = mdns_htons(data, record.rclass); + data = mdns_htonl(data, record.ttl); + data = mdns_htons(data, 0); // Length, to be filled later + return data; +} + +static inline void* +mdns_answer_add_record(void* buffer, size_t capacity, void* data, mdns_record_t record, + mdns_string_table_t* string_table) { + // TXT records will be coalesced into one record later + if (!data || (record.type == MDNS_RECORDTYPE_TXT)) + return data; + + data = mdns_answer_add_record_header(buffer, capacity, data, record, string_table); + if (!data) + return 0; + + // Pointer to length of record to be filled at end + void* record_length = MDNS_POINTER_OFFSET(data, -2); + void* record_data = data; + + size_t remain = capacity - MDNS_POINTER_DIFF(data, buffer); + switch (record.type) { + case MDNS_RECORDTYPE_PTR: + data = mdns_string_make(buffer, capacity, data, record.data.ptr.name.str, + record.data.ptr.name.length, string_table); + break; + + case MDNS_RECORDTYPE_SRV: + if (remain <= 6) + return 0; + data = mdns_htons(data, record.data.srv.priority); + data = mdns_htons(data, record.data.srv.weight); + data = mdns_htons(data, record.data.srv.port); + data = mdns_string_make(buffer, capacity, data, record.data.srv.name.str, + record.data.srv.name.length, string_table); + break; + + case MDNS_RECORDTYPE_A: + if (remain < 4) + return 0; + memcpy(data, &record.data.a.addr.sin_addr.s_addr, 4); + data = MDNS_POINTER_OFFSET(data, 4); + break; + + case MDNS_RECORDTYPE_AAAA: + if (remain < 16) + return 0; + memcpy(data, &record.data.aaaa.addr.sin6_addr, 16); // ipv6 address + data = MDNS_POINTER_OFFSET(data, 16); + break; + + default: + break; + } + + if (!data) + return 0; + + // Fill record length + mdns_htons(record_length, (uint16_t)MDNS_POINTER_DIFF(data, record_data)); + return data; +} + +static inline void +mdns_record_update_rclass_ttl(mdns_record_t* record, uint16_t rclass, uint32_t ttl) { + if (!record->rclass) + record->rclass = rclass; + if (!record->ttl || !ttl) + record->ttl = ttl; + record->rclass &= (uint16_t)(MDNS_CLASS_IN | MDNS_CACHE_FLUSH); + // Never flush PTR record + if (record->type == MDNS_RECORDTYPE_PTR) + record->rclass &= ~(uint16_t)MDNS_CACHE_FLUSH; +} + +static inline void* +mdns_answer_add_txt_record(void* buffer, size_t capacity, void* data, const mdns_record_t* records, + size_t record_count, uint16_t rclass, uint32_t ttl, + mdns_string_table_t* string_table) { + // Pointer to length of record to be filled at end + void* record_length = 0; + void* record_data = 0; + + size_t remain = 0; + for (size_t irec = 0; data && (irec < record_count); ++irec) { + if (records[irec].type != MDNS_RECORDTYPE_TXT) + continue; + + mdns_record_t record = records[irec]; + mdns_record_update_rclass_ttl(&record, rclass, ttl); + if (!record_data) { + data = mdns_answer_add_record_header(buffer, capacity, data, record, string_table); + if (!data) + return data; + record_length = MDNS_POINTER_OFFSET(data, -2); + record_data = data; + } + + // TXT strings are unlikely to be shared, just make then raw. Also need one byte for + // termination, thus the <= check + size_t string_length = record.data.txt.key.length + record.data.txt.value.length + 1; + if (!data) + return 0; + remain = capacity - MDNS_POINTER_DIFF(data, buffer); + if ((remain <= string_length) || (string_length > 0x3FFF)) + return 0; + + unsigned char* strdata = (unsigned char*)data; + *strdata++ = (unsigned char)string_length; + memcpy(strdata, record.data.txt.key.str, record.data.txt.key.length); + strdata += record.data.txt.key.length; + *strdata++ = '='; + memcpy(strdata, record.data.txt.value.str, record.data.txt.value.length); + strdata += record.data.txt.value.length; + + data = strdata; + } + + // Fill record length + if (record_data) + mdns_htons(record_length, (uint16_t)MDNS_POINTER_DIFF(data, record_data)); + + return data; +} + +static inline uint16_t +mdns_answer_get_record_count(const mdns_record_t* records, size_t record_count) { + // TXT records will be coalesced into one record + uint16_t total_count = 0; + uint16_t txt_record = 0; + for (size_t irec = 0; irec < record_count; ++irec) { + if (records[irec].type == MDNS_RECORDTYPE_TXT) + txt_record = 1; + else + ++total_count; + } + return total_count + txt_record; +} + +static inline int +mdns_query_answer_unicast(int sock, const void* address, size_t address_size, void* buffer, + size_t capacity, uint16_t query_id, mdns_record_type_t record_type, + const char* name, size_t name_length, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count) { + if (capacity < (sizeof(struct mdns_header_t) + 32 + 4)) + return -1; + + // According to RFC 6762: + // The cache-flush bit MUST NOT be set in any resource records in a response message + // sent in legacy unicast responses to UDP ports other than 5353. + uint16_t rclass = MDNS_CLASS_IN; + uint32_t ttl = 10; + + // Basic answer structure + struct mdns_header_t* header = (struct mdns_header_t*)buffer; + header->query_id = htons(query_id); + header->flags = htons(0x8400); + header->questions = htons(1); + header->answer_rrs = htons(1); + header->authority_rrs = htons(mdns_answer_get_record_count(authority, authority_count)); + header->additional_rrs = htons(mdns_answer_get_record_count(additional, additional_count)); + + mdns_string_table_t string_table = {{0}, 0, 0}; + void* data = MDNS_POINTER_OFFSET(buffer, sizeof(struct mdns_header_t)); + + // Fill in question + data = mdns_answer_add_question_unicast(buffer, capacity, data, record_type, name, name_length, + &string_table); + + // Fill in answer + answer.rclass = rclass; + answer.ttl = ttl; + data = mdns_answer_add_record(buffer, capacity, data, answer, &string_table); + + // Fill in authority records + for (size_t irec = 0; data && (irec < authority_count); ++irec) { + mdns_record_t record = authority[irec]; + record.rclass = rclass; + if (!record.ttl) + record.ttl = ttl; + data = mdns_answer_add_record(buffer, capacity, data, record, &string_table); + } + data = mdns_answer_add_txt_record(buffer, capacity, data, authority, authority_count, + rclass, ttl, &string_table); + + // Fill in additional records + for (size_t irec = 0; data && (irec < additional_count); ++irec) { + mdns_record_t record = additional[irec]; + record.rclass = rclass; + if (!record.ttl) + record.ttl = ttl; + data = mdns_answer_add_record(buffer, capacity, data, record, &string_table); + } + data = mdns_answer_add_txt_record(buffer, capacity, data, additional, additional_count, + rclass, ttl, &string_table); + if (!data) + return -1; + + size_t tosend = MDNS_POINTER_DIFF(data, buffer); + return mdns_unicast_send(sock, address, address_size, buffer, tosend); +} + +static inline int +mdns_answer_multicast_rclass_ttl(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count, + uint16_t rclass, uint32_t ttl) { + if (capacity < (sizeof(struct mdns_header_t) + 32 + 4)) + return -1; + + // Basic answer structure + struct mdns_header_t* header = (struct mdns_header_t*)buffer; + header->query_id = 0; + header->flags = htons(0x8400); + header->questions = 0; + header->answer_rrs = htons(1); + header->authority_rrs = htons(mdns_answer_get_record_count(authority, authority_count)); + header->additional_rrs = htons(mdns_answer_get_record_count(additional, additional_count)); + + mdns_string_table_t string_table = {{0}, 0, 0}; + void* data = MDNS_POINTER_OFFSET(buffer, sizeof(struct mdns_header_t)); + + // Fill in answer + mdns_record_t record = answer; + mdns_record_update_rclass_ttl(&record, rclass, ttl); + data = mdns_answer_add_record(buffer, capacity, data, record, &string_table); + + // Fill in authority records + for (size_t irec = 0; data && (irec < authority_count); ++irec) { + record = authority[irec]; + mdns_record_update_rclass_ttl(&record, rclass, ttl); + data = mdns_answer_add_record(buffer, capacity, data, record, &string_table); + } + data = mdns_answer_add_txt_record(buffer, capacity, data, authority, authority_count, + rclass, ttl, &string_table); + + // Fill in additional records + for (size_t irec = 0; data && (irec < additional_count); ++irec) { + record = additional[irec]; + mdns_record_update_rclass_ttl(&record, rclass, ttl); + data = mdns_answer_add_record(buffer, capacity, data, record, &string_table); + } + data = mdns_answer_add_txt_record(buffer, capacity, data, additional, additional_count, + rclass, ttl, &string_table); + if (!data) + return -1; + + size_t tosend = MDNS_POINTER_DIFF(data, buffer); + return mdns_multicast_send(sock, buffer, tosend); +} + +static inline int +mdns_query_answer_multicast(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count) { + return mdns_answer_multicast_rclass_ttl(sock, buffer, capacity, answer, authority, + authority_count, additional, additional_count, + MDNS_CLASS_IN, 60); +} + +static inline int +mdns_announce_multicast(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count) { + return mdns_answer_multicast_rclass_ttl(sock, buffer, capacity, answer, authority, + authority_count, additional, additional_count, + MDNS_CLASS_IN | MDNS_CACHE_FLUSH, 60); +} + +static inline int +mdns_goodbye_multicast(int sock, void* buffer, size_t capacity, mdns_record_t answer, + const mdns_record_t* authority, size_t authority_count, + const mdns_record_t* additional, size_t additional_count) { + // Goodbye should have ttl of 0 + return mdns_answer_multicast_rclass_ttl(sock, buffer, capacity, answer, authority, + authority_count, additional, additional_count, + MDNS_CLASS_IN, 0); +} + +static inline mdns_string_t +mdns_record_parse_ptr(const void* buffer, size_t size, size_t offset, size_t length, + char* strbuffer, size_t capacity) { + // PTR record is just a string + if ((size >= offset + length) && (length >= 2)) + return mdns_string_extract(buffer, size, &offset, strbuffer, capacity); + mdns_string_t empty = {0, 0}; + return empty; +} + +static inline mdns_record_srv_t +mdns_record_parse_srv(const void* buffer, size_t size, size_t offset, size_t length, + char* strbuffer, size_t capacity) { + mdns_record_srv_t srv; + memset(&srv, 0, sizeof(mdns_record_srv_t)); + // Read the service priority, weight, port number and the discovery name + // SRV record format (http://www.ietf.org/rfc/rfc2782.txt): + // 2 bytes network-order unsigned priority + // 2 bytes network-order unsigned weight + // 2 bytes network-order unsigned port + // string: discovery (domain) name, minimum 2 bytes when compressed + if ((size >= offset + length) && (length >= 8)) { + const uint16_t* recorddata = (const uint16_t*)MDNS_POINTER_OFFSET_CONST(buffer, offset); + srv.priority = mdns_ntohs(recorddata++); + srv.weight = mdns_ntohs(recorddata++); + srv.port = mdns_ntohs(recorddata++); + offset += 6; + srv.name = mdns_string_extract(buffer, size, &offset, strbuffer, capacity); + } + return srv; +} + +static inline struct sockaddr_in* +mdns_record_parse_a(const void* buffer, size_t size, size_t offset, size_t length, + struct sockaddr_in* addr) { + memset(addr, 0, sizeof(struct sockaddr_in)); + addr->sin_family = AF_INET; +#ifdef __APPLE__ + addr->sin_len = sizeof(struct sockaddr_in); +#endif + if ((size >= offset + length) && (length == 4)) + memcpy(&addr->sin_addr.s_addr, MDNS_POINTER_OFFSET(buffer, offset), 4); + return addr; +} + +static inline struct sockaddr_in6* +mdns_record_parse_aaaa(const void* buffer, size_t size, size_t offset, size_t length, + struct sockaddr_in6* addr) { + memset(addr, 0, sizeof(struct sockaddr_in6)); + addr->sin6_family = AF_INET6; +#ifdef __APPLE__ + addr->sin6_len = sizeof(struct sockaddr_in6); +#endif + if ((size >= offset + length) && (length == 16)) + memcpy(&addr->sin6_addr, MDNS_POINTER_OFFSET(buffer, offset), 16); + return addr; +} + +static inline size_t +mdns_record_parse_txt(const void* buffer, size_t size, size_t offset, size_t length, + mdns_record_txt_t* records, size_t capacity) { + size_t parsed = 0; + const char* strdata; + size_t end = offset + length; + + if (size < end) + end = size; + + while ((offset < end) && (parsed < capacity)) { + strdata = (const char*)MDNS_POINTER_OFFSET(buffer, offset); + size_t sublength = *(const unsigned char*)strdata; + + ++strdata; + offset += sublength + 1; + + size_t separator = 0; + for (size_t c = 0; c < sublength; ++c) { + // DNS-SD TXT record keys MUST be printable US-ASCII, [0x20, 0x7E] + if ((strdata[c] < 0x20) || (strdata[c] > 0x7E)) + break; + if (strdata[c] == '=') { + separator = c; + break; + } + } + + if (!separator) + continue; + + if (separator < sublength) { + records[parsed].key.str = strdata; + records[parsed].key.length = separator; + records[parsed].value.str = strdata + separator + 1; + records[parsed].value.length = sublength - (separator + 1); + } else { + records[parsed].key.str = strdata; + records[parsed].key.length = sublength; + } + + ++parsed; + } + + return parsed; +} + +#ifdef _WIN32 +#undef strncasecmp +#endif + +#ifdef __cplusplus +} +#endif