/* * SCTP protocol * Copyright (c) 2012 Luca Barbato * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * * sctp url_protocol * * url syntax: sctp://host:port[?option=val...] * option: 'listen' : listen for an incoming connection * 'max_streams=n' : set the maximum number of streams * 'reuse=1' : enable reusing the socket [TBD] * * by setting the maximum number of streams the protocol will use the * first two bytes of the incoming/outgoing buffer to store the * stream number of the packet being read/written. * @see sctp_read * @see sctp_write */ #include <netinet/in.h> #include <netinet/sctp.h> #include "config.h" #if HAVE_POLL_H #include <poll.h> #endif #include "libavutil/intreadwrite.h" #include "libavutil/parseutils.h" #include "avformat.h" #include "internal.h" #include "network.h" #include "os_support.h" #include "url.h" /* * The sctp_recvmsg and sctp_sendmsg functions are part of the user * library that offers support for the SCTP kernel Implementation. * To avoid build-time clashes the functions sport an ff_-prefix here. * The main purpose of this code is to provide the SCTP Socket API * mappings for user applications to interface with SCTP in the kernel. * * This implementation is based on the Socket API Extensions for SCTP * defined in <draft-ietf-tsvwg-sctpsocket-10.txt> * * Copyright (c) 2003 International Business Machines, Corp. * * Written or modified by: * Ryan Layer <rmlayer@us.ibm.com> */ static int ff_sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from, socklen_t *fromlen, struct sctp_sndrcvinfo *sinfo, int *msg_flags) { int recvb; struct iovec iov; char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; struct msghdr inmsg = { 0 }; struct cmsghdr *cmsg = NULL; iov.iov_base = msg; iov.iov_len = len; inmsg.msg_name = from; inmsg.msg_namelen = fromlen ? *fromlen : 0; inmsg.msg_iov = &iov; inmsg.msg_iovlen = 1; inmsg.msg_control = incmsg; inmsg.msg_controllen = sizeof(incmsg); if ((recvb = recvmsg(s, &inmsg, msg_flags ? *msg_flags : 0)) < 0) return recvb; if (fromlen) *fromlen = inmsg.msg_namelen; if (msg_flags) *msg_flags = inmsg.msg_flags; for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg != NULL; cmsg = CMSG_NXTHDR(&inmsg, cmsg)) { if ((IPPROTO_SCTP == cmsg->cmsg_level) && (SCTP_SNDRCV == cmsg->cmsg_type)) break; } /* Copy sinfo. */ if (cmsg) memcpy(sinfo, CMSG_DATA(cmsg), sizeof(struct sctp_sndrcvinfo)); return recvb; } static int ff_sctp_send(int s, const void *msg, size_t len, const struct sctp_sndrcvinfo *sinfo, int flags) { struct msghdr outmsg; struct iovec iov; outmsg.msg_name = NULL; outmsg.msg_namelen = 0; outmsg.msg_iov = &iov; iov.iov_base = msg; iov.iov_len = len; outmsg.msg_iovlen = 1; outmsg.msg_controllen = 0; if (sinfo) { char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; struct cmsghdr *cmsg; outmsg.msg_control = outcmsg; outmsg.msg_controllen = sizeof(outcmsg); outmsg.msg_flags = 0; cmsg = CMSG_FIRSTHDR(&outmsg); cmsg->cmsg_level = IPPROTO_SCTP; cmsg->cmsg_type = SCTP_SNDRCV; cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo)); outmsg.msg_controllen = cmsg->cmsg_len; memcpy(CMSG_DATA(cmsg), sinfo, sizeof(struct sctp_sndrcvinfo)); } return sendmsg(s, &outmsg, flags); } typedef struct SCTPContext { int fd; int max_streams; struct sockaddr_storage dest_addr; socklen_t dest_addr_len; } SCTPContext; static int sctp_open(URLContext *h, const char *uri, int flags) { struct addrinfo *ai, *cur_ai; struct addrinfo hints = { 0 }; struct sctp_event_subscribe event = { 0 }; struct sctp_initmsg initparams = { 0 }; int port; int fd = -1; SCTPContext *s = h->priv_data; const char *p; char buf[256]; int ret, listen_socket = 0; char hostname[1024], proto[1024], path[1024]; char portstr[10]; av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname), &port, path, sizeof(path), uri); if (strcmp(proto, "sctp")) return AVERROR(EINVAL); if (port <= 0 || port >= 65536) { av_log(s, AV_LOG_ERROR, "Port missing in uri\n"); return AVERROR(EINVAL); } s->max_streams = 0; p = strchr(uri, '?'); if (p) { if (av_find_info_tag(buf, sizeof(buf), "listen", p)) listen_socket = 1; if (av_find_info_tag(buf, sizeof(buf), "max_streams", p)) s->max_streams = strtol(buf, NULL, 10); } hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; snprintf(portstr, sizeof(portstr), "%d", port); ret = getaddrinfo(hostname, portstr, &hints, &ai); if (ret) { av_log(h, AV_LOG_ERROR, "Failed to resolve hostname %s: %s\n", hostname, gai_strerror(ret)); return AVERROR(EIO); } cur_ai = ai; fd = ff_socket(cur_ai->ai_family, SOCK_STREAM, IPPROTO_SCTP); if (fd < 0) goto fail; s->dest_addr_len = sizeof(s->dest_addr); if (listen_socket) { int fd1; ret = bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen); listen(fd, 100); fd1 = accept(fd, NULL, NULL); closesocket(fd); fd = fd1; } else ret = connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen); ff_socket_nonblock(fd, 1); event.sctp_data_io_event = 1; /* TODO: Subscribe to more event types and handle them */ if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &event, sizeof(event)) != 0) { av_log(h, AV_LOG_ERROR, "SCTP ERROR: Unable to subscribe to events\n"); goto fail; } if (s->max_streams) { initparams.sinit_max_instreams = s->max_streams; initparams.sinit_num_ostreams = s->max_streams; if (setsockopt(fd, IPPROTO_SCTP, SCTP_INITMSG, &initparams, sizeof(initparams)) < 0) av_log(h, AV_LOG_ERROR, "SCTP ERROR: Unable to initialize socket max streams %d\n", s->max_streams); } h->priv_data = s; h->is_streamed = 1; s->fd = fd; freeaddrinfo(ai); return 0; fail: ret = AVERROR(EIO); freeaddrinfo(ai); return ret; } static int sctp_wait_fd(int fd, int write) { int ev = write ? POLLOUT : POLLIN; struct pollfd p = { .fd = fd, .events = ev, .revents = 0 }; int ret; ret = poll(&p, 1, 100); return ret < 0 ? ff_neterrno() : p.revents & ev ? 0 : AVERROR(EAGAIN); } static int sctp_read(URLContext *h, uint8_t *buf, int size) { SCTPContext *s = h->priv_data; int ret; if (!(h->flags & AVIO_FLAG_NONBLOCK)) { ret = sctp_wait_fd(s->fd, 0); if (ret < 0) return ret; } if (s->max_streams) { /*StreamId is introduced as a 2byte code into the stream*/ struct sctp_sndrcvinfo info = { 0 }; ret = ff_sctp_recvmsg(s->fd, buf + 2, size - 2, NULL, 0, &info, 0); AV_WB16(buf, info.sinfo_stream); ret = ret < 0 ? ret : ret + 2; } else ret = recv(s->fd, buf, size, 0); return ret < 0 ? ff_neterrno() : ret; } static int sctp_write(URLContext *h, const uint8_t *buf, int size) { SCTPContext *s = h->priv_data; int ret; if (!(h->flags & AVIO_FLAG_NONBLOCK)) { ret = sctp_wait_fd(s->fd, 1); if (ret < 0) return ret; } if (s->max_streams) { /*StreamId is introduced as a 2byte code into the stream*/ struct sctp_sndrcvinfo info = { 0 }; info.sinfo_stream = AV_RB16(buf); if (info.sinfo_stream > s->max_streams) abort(); ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR); } else ret = send(s->fd, buf, size, 0); return ret < 0 ? ff_neterrno() : ret; } static int sctp_close(URLContext *h) { SCTPContext *s = h->priv_data; closesocket(s->fd); return 0; } static int sctp_get_file_handle(URLContext *h) { SCTPContext *s = h->priv_data; return s->fd; } URLProtocol ff_sctp_protocol = { .name = "sctp", .url_open = sctp_open, .url_read = sctp_read, .url_write = sctp_write, .url_close = sctp_close, .url_get_file_handle = sctp_get_file_handle, .priv_data_size = sizeof(SCTPContext), .flags = URL_PROTOCOL_FLAG_NETWORK, };