1/*
2 * SCTP protocol
3 * Copyright (c) 2012 Luca Barbato
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 *
25 * sctp url_protocol
26 *
27 * url syntax: sctp://host:port[?option=val...]
28 * option: 'listen'        : listen for an incoming connection
29 *         'max_streams=n' : set the maximum number of streams
30 *         'reuse=1'       : enable reusing the socket [TBD]
31 *
32 * by setting the maximum number of streams the protocol will use the
33 * first two bytes of the incoming/outgoing buffer to store the
34 * stream number of the packet being read/written.
35 * @see sctp_read
36 * @see sctp_write
37 */
38
39
40#include <netinet/in.h>
41#include <netinet/sctp.h>
42
43#include "config.h"
44
45#if HAVE_POLL_H
46#include <poll.h>
47#endif
48
49#include "libavutil/intreadwrite.h"
50#include "libavutil/parseutils.h"
51#include "avformat.h"
52#include "internal.h"
53#include "network.h"
54#include "os_support.h"
55#include "url.h"
56
57/*
58 * The sctp_recvmsg and sctp_sendmsg functions are part of the user
59 * library that offers support for the SCTP kernel Implementation.
60 * To avoid build-time clashes the functions sport an ff_-prefix here.
61 * The main purpose of this code is to provide the SCTP Socket API
62 * mappings for user applications to interface with SCTP in the kernel.
63 *
64 * This implementation is based on the Socket API Extensions for SCTP
65 * defined in <draft-ietf-tsvwg-sctpsocket-10.txt>
66 *
67 * Copyright (c) 2003 International Business Machines, Corp.
68 *
69 * Written or modified by:
70 *  Ryan Layer <rmlayer@us.ibm.com>
71 */
72
73static int ff_sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from,
74                           socklen_t *fromlen, struct sctp_sndrcvinfo *sinfo,
75                           int *msg_flags)
76{
77    int recvb;
78    struct iovec iov;
79    char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
80    struct msghdr inmsg  = { 0 };
81    struct cmsghdr *cmsg = NULL;
82
83    iov.iov_base = msg;
84    iov.iov_len  = len;
85
86    inmsg.msg_name       = from;
87    inmsg.msg_namelen    = fromlen ? *fromlen : 0;
88    inmsg.msg_iov        = &iov;
89    inmsg.msg_iovlen     = 1;
90    inmsg.msg_control    = incmsg;
91    inmsg.msg_controllen = sizeof(incmsg);
92
93    if ((recvb = recvmsg(s, &inmsg, msg_flags ? *msg_flags : 0)) < 0)
94        return recvb;
95
96    if (fromlen)
97        *fromlen   = inmsg.msg_namelen;
98    if (msg_flags)
99        *msg_flags = inmsg.msg_flags;
100
101    for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg != NULL;
102         cmsg = CMSG_NXTHDR(&inmsg, cmsg)) {
103        if ((IPPROTO_SCTP == cmsg->cmsg_level) &&
104            (SCTP_SNDRCV  == cmsg->cmsg_type))
105            break;
106    }
107
108    /* Copy sinfo. */
109    if (cmsg)
110        memcpy(sinfo, CMSG_DATA(cmsg), sizeof(struct sctp_sndrcvinfo));
111
112    return recvb;
113}
114
115static int ff_sctp_send(int s, const void *msg, size_t len,
116                        const struct sctp_sndrcvinfo *sinfo, int flags)
117{
118    struct msghdr outmsg;
119    struct iovec iov;
120
121    outmsg.msg_name       = NULL;
122    outmsg.msg_namelen    = 0;
123    outmsg.msg_iov        = &iov;
124    iov.iov_base          = (void*)msg;
125    iov.iov_len           = len;
126    outmsg.msg_iovlen     = 1;
127    outmsg.msg_controllen = 0;
128
129    if (sinfo) {
130        char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
131        struct cmsghdr *cmsg;
132
133        outmsg.msg_control    = outcmsg;
134        outmsg.msg_controllen = sizeof(outcmsg);
135        outmsg.msg_flags      = 0;
136
137        cmsg             = CMSG_FIRSTHDR(&outmsg);
138        cmsg->cmsg_level = IPPROTO_SCTP;
139        cmsg->cmsg_type  = SCTP_SNDRCV;
140        cmsg->cmsg_len   = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
141
142        outmsg.msg_controllen = cmsg->cmsg_len;
143        memcpy(CMSG_DATA(cmsg), sinfo, sizeof(struct sctp_sndrcvinfo));
144    }
145
146    return sendmsg(s, &outmsg, flags);
147}
148
149typedef struct SCTPContext {
150    int fd;
151    int max_streams;
152    struct sockaddr_storage dest_addr;
153    socklen_t dest_addr_len;
154} SCTPContext;
155
156static int sctp_open(URLContext *h, const char *uri, int flags)
157{
158    struct addrinfo *ai, *cur_ai;
159    struct addrinfo hints             = { 0 };
160    struct sctp_event_subscribe event = { 0 };
161    struct sctp_initmsg initparams    = { 0 };
162    int port;
163    int fd         = -1;
164    SCTPContext *s = h->priv_data;
165    const char *p;
166    char buf[256];
167    int ret, listen_socket = 0;
168    char hostname[1024], proto[1024], path[1024];
169    char portstr[10];
170
171    av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname),
172                 &port, path, sizeof(path), uri);
173    if (strcmp(proto, "sctp"))
174        return AVERROR(EINVAL);
175    if (port <= 0 || port >= 65536) {
176        av_log(s, AV_LOG_ERROR, "Port missing in uri\n");
177        return AVERROR(EINVAL);
178    }
179
180    s->max_streams = 0;
181    p = strchr(uri, '?');
182    if (p) {
183        if (av_find_info_tag(buf, sizeof(buf), "listen", p))
184            listen_socket = 1;
185        if (av_find_info_tag(buf, sizeof(buf), "max_streams", p))
186            s->max_streams = strtol(buf, NULL, 10);
187    }
188
189    hints.ai_family   = AF_UNSPEC;
190    hints.ai_socktype = SOCK_STREAM;
191    snprintf(portstr, sizeof(portstr), "%d", port);
192    ret = getaddrinfo(hostname, portstr, &hints, &ai);
193    if (ret) {
194        av_log(h, AV_LOG_ERROR, "Failed to resolve hostname %s: %s\n",
195               hostname, gai_strerror(ret));
196        return AVERROR(EIO);
197    }
198
199    cur_ai = ai;
200
201    fd = ff_socket(cur_ai->ai_family, SOCK_STREAM, IPPROTO_SCTP);
202    if (fd < 0)
203        goto fail;
204
205    s->dest_addr_len = sizeof(s->dest_addr);
206
207    if (listen_socket) {
208        int fd1;
209        ret = bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen);
210        listen(fd, 100);
211        fd1 = accept(fd, NULL, NULL);
212        closesocket(fd);
213        fd  = fd1;
214    } else
215        ret = connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen);
216
217    ff_socket_nonblock(fd, 1);
218
219    event.sctp_data_io_event = 1;
220    /* TODO: Subscribe to more event types and handle them */
221
222    if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &event,
223                   sizeof(event)) != 0) {
224        av_log(h, AV_LOG_ERROR,
225               "SCTP ERROR: Unable to subscribe to events\n");
226        goto fail;
227    }
228
229    if (s->max_streams) {
230        initparams.sinit_max_instreams = s->max_streams;
231        initparams.sinit_num_ostreams  = s->max_streams;
232        if (setsockopt(fd, IPPROTO_SCTP, SCTP_INITMSG, &initparams,
233                       sizeof(initparams)) < 0)
234            av_log(h, AV_LOG_ERROR,
235                   "SCTP ERROR: Unable to initialize socket max streams %d\n",
236                   s->max_streams);
237    }
238
239    h->priv_data   = s;
240    h->is_streamed = 1;
241    s->fd          = fd;
242    freeaddrinfo(ai);
243    return 0;
244
245fail:
246    ret = AVERROR(EIO);
247    freeaddrinfo(ai);
248    return ret;
249}
250
251static int sctp_wait_fd(int fd, int write)
252{
253    int ev          = write ? POLLOUT : POLLIN;
254    struct pollfd p = { .fd = fd, .events = ev, .revents = 0 };
255    int ret;
256
257    ret = poll(&p, 1, 100);
258    return ret < 0 ? ff_neterrno() : p.revents & ev ? 0 : AVERROR(EAGAIN);
259}
260
261static int sctp_read(URLContext *h, uint8_t *buf, int size)
262{
263    SCTPContext *s = h->priv_data;
264    int ret;
265
266    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
267        ret = sctp_wait_fd(s->fd, 0);
268        if (ret < 0)
269            return ret;
270    }
271
272    if (s->max_streams) {
273        /*StreamId is introduced as a 2byte code into the stream*/
274        struct sctp_sndrcvinfo info = { 0 };
275        ret = ff_sctp_recvmsg(s->fd, buf + 2, size - 2, NULL, 0, &info, 0);
276        AV_WB16(buf, info.sinfo_stream);
277        ret = ret < 0 ? ret : ret + 2;
278    } else
279        ret = recv(s->fd, buf, size, 0);
280
281    return ret < 0 ? ff_neterrno() : ret;
282}
283
284static int sctp_write(URLContext *h, const uint8_t *buf, int size)
285{
286    SCTPContext *s = h->priv_data;
287    int ret;
288
289    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
290        ret = sctp_wait_fd(s->fd, 1);
291        if (ret < 0)
292            return ret;
293    }
294
295    if (s->max_streams) {
296        /*StreamId is introduced as a 2byte code into the stream*/
297        struct sctp_sndrcvinfo info = { 0 };
298        info.sinfo_stream           = AV_RB16(buf);
299        if (info.sinfo_stream > s->max_streams) {
300            av_log(h, AV_LOG_ERROR, "bad input data\n");
301            return AVERROR(EINVAL);
302        }
303        ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR);
304    } else
305        ret = send(s->fd, buf, size, 0);
306
307    return ret < 0 ? ff_neterrno() : ret;
308}
309
310static int sctp_close(URLContext *h)
311{
312    SCTPContext *s = h->priv_data;
313    closesocket(s->fd);
314    return 0;
315}
316
317static int sctp_get_file_handle(URLContext *h)
318{
319    SCTPContext *s = h->priv_data;
320    return s->fd;
321}
322
323URLProtocol ff_sctp_protocol = {
324    .name                = "sctp",
325    .url_open            = sctp_open,
326    .url_read            = sctp_read,
327    .url_write           = sctp_write,
328    .url_close           = sctp_close,
329    .url_get_file_handle = sctp_get_file_handle,
330    .priv_data_size      = sizeof(SCTPContext),
331    .flags               = URL_PROTOCOL_FLAG_NETWORK,
332};
333