static int sap_write_header(AVFormatContext *s) { struct SAPState *sap = s->priv_data; char host[1024], path[1024], url[1024], announce_addr[50] = ""; char *option_list; int port = 9875, base_port = 5004, i, pos = 0, same_port = 0, ttl = 255; AVFormatContext **contexts = NULL; int ret = 0; struct sockaddr_storage localaddr; socklen_t addrlen = sizeof(localaddr); int udp_fd; AVDictionaryEntry* title = av_dict_get(s->metadata, "title", NULL, 0); if (!ff_network_init()) return AVERROR(EIO); /* extract hostname and port */ av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &base_port, path, sizeof(path), s->filename); if (base_port < 0) base_port = 5004; /* search for options */ option_list = strrchr(path, '?'); if (option_list) { char buf[50]; if (av_find_info_tag(buf, sizeof(buf), "announce_port", option_list)) { port = strtol(buf, NULL, 10); } if (av_find_info_tag(buf, sizeof(buf), "same_port", option_list)) { same_port = strtol(buf, NULL, 10); } if (av_find_info_tag(buf, sizeof(buf), "ttl", option_list)) { ttl = strtol(buf, NULL, 10); } if (av_find_info_tag(buf, sizeof(buf), "announce_addr", option_list)) { av_strlcpy(announce_addr, buf, sizeof(announce_addr)); } } if (!announce_addr[0]) { struct addrinfo hints = { 0 }, *ai = NULL; hints.ai_family = AF_UNSPEC; if (getaddrinfo(host, NULL, &hints, &ai)) { av_log(s, AV_LOG_ERROR, "Unable to resolve %s\n", host); ret = AVERROR(EIO); goto fail; } if (ai->ai_family == AF_INET) { /* Also known as sap.mcast.net */ av_strlcpy(announce_addr, "224.2.127.254", sizeof(announce_addr)); #if HAVE_STRUCT_SOCKADDR_IN6 } else if (ai->ai_family == AF_INET6) { /* With IPv6, you can use the same destination in many different * multicast subnets, to choose how far you want it routed. * This one is intended to be routed globally. */ av_strlcpy(announce_addr, "ff0e::2:7ffe", sizeof(announce_addr)); #endif } else { freeaddrinfo(ai); av_log(s, AV_LOG_ERROR, "Host %s resolved to unsupported " "address family\n", host); ret = AVERROR(EIO); goto fail; } freeaddrinfo(ai); } sap->protocols = ffurl_get_protocols(NULL, NULL); if (!sap->protocols) { ret = AVERROR(ENOMEM); goto fail; } contexts = av_mallocz(sizeof(AVFormatContext*) * s->nb_streams); if (!contexts) { ret = AVERROR(ENOMEM); goto fail; } s->start_time_realtime = av_gettime(); for (i = 0; i < s->nb_streams; i++) { URLContext *fd; ff_url_join(url, sizeof(url), "rtp", NULL, host, base_port, "?ttl=%d", ttl); if (!same_port) base_port += 2; ret = ffurl_open(&fd, url, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL, sap->protocols); if (ret) { ret = AVERROR(EIO); goto fail; } ret = ff_rtp_chain_mux_open(&contexts[i], s, s->streams[i], fd, 0, i); if (ret < 0) goto fail; s->streams[i]->priv_data = contexts[i]; s->streams[i]->time_base = contexts[i]->streams[0]->time_base; av_strlcpy(contexts[i]->filename, url, sizeof(contexts[i]->filename)); } if (s->nb_streams > 0 && title) av_dict_set(&contexts[0]->metadata, "title", title->value, 0); ff_url_join(url, sizeof(url), "udp", NULL, announce_addr, port, "?ttl=%d&connect=1", ttl); ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL, sap->protocols); if (ret) { ret = AVERROR(EIO); goto fail; } udp_fd = ffurl_get_file_handle(sap->ann_fd); if (getsockname(udp_fd, (struct sockaddr*) &localaddr, &addrlen)) { ret = AVERROR(EIO); goto fail; } if (localaddr.ss_family != AF_INET #if HAVE_STRUCT_SOCKADDR_IN6 && localaddr.ss_family != AF_INET6 #endif ) { av_log(s, AV_LOG_ERROR, "Unsupported protocol family\n"); ret = AVERROR(EIO); goto fail; } sap->ann_size = 8192; sap->ann = av_mallocz(sap->ann_size); if (!sap->ann) { ret = AVERROR(EIO); goto fail; } sap->ann[pos] = (1 << 5); #if HAVE_STRUCT_SOCKADDR_IN6 if (localaddr.ss_family == AF_INET6) sap->ann[pos] |= 0x10; #endif pos++; sap->ann[pos++] = 0; /* Authentication length */ AV_WB16(&sap->ann[pos], av_get_random_seed()); pos += 2; if (localaddr.ss_family == AF_INET) { memcpy(&sap->ann[pos], &((struct sockaddr_in*)&localaddr)->sin_addr, sizeof(struct in_addr)); pos += sizeof(struct in_addr); #if HAVE_STRUCT_SOCKADDR_IN6 } else { memcpy(&sap->ann[pos], &((struct sockaddr_in6*)&localaddr)->sin6_addr, sizeof(struct in6_addr)); pos += sizeof(struct in6_addr); #endif } av_strlcpy(&sap->ann[pos], "application/sdp", sap->ann_size - pos); pos += strlen(&sap->ann[pos]) + 1; if (av_sdp_create(contexts, s->nb_streams, &sap->ann[pos], sap->ann_size - pos)) { ret = AVERROR_INVALIDDATA; goto fail; } av_freep(&contexts); av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", &sap->ann[pos]); pos += strlen(&sap->ann[pos]); sap->ann_size = pos; if (sap->ann_size > sap->ann_fd->max_packet_size) { av_log(s, AV_LOG_ERROR, "Announcement too large to send in one " "packet\n"); goto fail; } return 0; fail: av_free(contexts); sap_write_close(s); return ret; }