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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-07 11:13:41 +02:00
FFmpeg/libavformat/sapdec.c
Andreas Rheinhardt 7001ff74ba avformat/aviobuf: Add ffio_init_(read|write)_context()
Most users of ffio_init_context() simply want to wrap
a buffer into an AVIOContext; they do not provide
function pointers at all.

Therefore this commit adds shortcuts for these two common
operations. This also allows to accept const data when reading
(i.e. the const is now cast away at a central place in
ffio_init_read_context() instead of at several callers).
This also allows to constify the data in ff_text_init_buf().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-09-07 00:41:45 +02:00

245 lines
7.1 KiB
C

/*
* Session Announcement Protocol (RFC 2974) demuxer
* Copyright (c) 2010 Martin Storsjo
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "network.h"
#include "os_support.h"
#include "internal.h"
#include "avio_internal.h"
#include "url.h"
#include "rtpdec.h"
#if HAVE_POLL_H
#include <poll.h>
#endif
struct SAPState {
URLContext *ann_fd;
AVFormatContext *sdp_ctx;
FFIOContext sdp_pb;
uint16_t hash;
char *sdp;
int eof;
};
static int sap_probe(const AVProbeData *p)
{
if (av_strstart(p->filename, "sap:", NULL))
return AVPROBE_SCORE_MAX;
return 0;
}
static int sap_read_close(AVFormatContext *s)
{
struct SAPState *sap = s->priv_data;
if (sap->sdp_ctx)
avformat_close_input(&sap->sdp_ctx);
ffurl_closep(&sap->ann_fd);
av_freep(&sap->sdp);
ff_network_close();
return 0;
}
static int sap_read_header(AVFormatContext *s)
{
struct SAPState *sap = s->priv_data;
char host[1024], path[1024], url[1024];
uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
const AVInputFormat *infmt;
int port;
int ret, i;
if (!ff_network_init())
return AVERROR(EIO);
av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
path, sizeof(path), s->url);
if (port < 0)
port = 9875;
if (!host[0]) {
/* Listen for announcements on sap.mcast.net if no host was specified */
av_strlcpy(host, "224.2.127.254", sizeof(host));
}
ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
port);
ret = ffurl_open_whitelist(&sap->ann_fd, url, AVIO_FLAG_READ,
&s->interrupt_callback, NULL,
s->protocol_whitelist, s->protocol_blacklist, NULL);
if (ret)
goto fail;
while (1) {
int addr_type, auth_len;
int pos;
ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
if (ret == AVERROR(EAGAIN))
continue;
if (ret < 0)
goto fail;
recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
if (ret < 8) {
av_log(s, AV_LOG_WARNING, "Received too short packet\n");
continue;
}
if ((recvbuf[0] & 0xe0) != 0x20) {
av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
"received\n");
continue;
}
if (recvbuf[0] & 0x04) {
av_log(s, AV_LOG_WARNING, "Received stream deletion "
"announcement\n");
continue;
}
addr_type = recvbuf[0] & 0x10;
auth_len = recvbuf[1];
sap->hash = AV_RB16(&recvbuf[2]);
pos = 4;
if (addr_type)
pos += 16; /* IPv6 */
else
pos += 4; /* IPv4 */
pos += auth_len * 4;
if (pos + 4 >= ret) {
av_log(s, AV_LOG_WARNING, "Received too short packet\n");
continue;
}
#define MIME "application/sdp"
if (strcmp(&recvbuf[pos], MIME) == 0) {
pos += strlen(MIME) + 1;
} else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
// Direct SDP without a mime type
} else {
av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
&recvbuf[pos]);
continue;
}
sap->sdp = av_strdup(&recvbuf[pos]);
if (!sap->sdp) {
ret = AVERROR(ENOMEM);
goto fail;
}
break;
}
av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
ffio_init_read_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp));
infmt = av_find_input_format("sdp");
if (!infmt)
goto fail;
sap->sdp_ctx = avformat_alloc_context();
if (!sap->sdp_ctx) {
ret = AVERROR(ENOMEM);
goto fail;
}
sap->sdp_ctx->max_delay = s->max_delay;
sap->sdp_ctx->pb = &sap->sdp_pb.pub;
sap->sdp_ctx->interrupt_callback = s->interrupt_callback;
if ((ret = ff_copy_whiteblacklists(sap->sdp_ctx, s)) < 0)
goto fail;
ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
if (ret < 0)
goto fail;
if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
s->ctx_flags |= AVFMTCTX_NOHEADER;
for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
AVStream *st = avformat_new_stream(s, NULL);
if (!st) {
ret = AVERROR(ENOMEM);
goto fail;
}
st->id = i;
avcodec_parameters_copy(st->codecpar, sap->sdp_ctx->streams[i]->codecpar);
st->time_base = sap->sdp_ctx->streams[i]->time_base;
}
return 0;
fail:
sap_read_close(s);
return ret;
}
static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
{
struct SAPState *sap = s->priv_data;
int fd = ffurl_get_file_handle(sap->ann_fd);
int n, ret;
struct pollfd p = {fd, POLLIN, 0};
uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
if (sap->eof)
return AVERROR_EOF;
while (1) {
n = poll(&p, 1, 0);
if (n <= 0 || !(p.revents & POLLIN))
break;
ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
if (ret >= 8) {
uint16_t hash = AV_RB16(&recvbuf[2]);
/* Should ideally check the source IP address, too */
if (recvbuf[0] & 0x04 && hash == sap->hash) {
/* Stream deletion */
sap->eof = 1;
return AVERROR_EOF;
}
}
}
ret = av_read_frame(sap->sdp_ctx, pkt);
if (ret < 0)
return ret;
if (s->ctx_flags & AVFMTCTX_NOHEADER) {
while (sap->sdp_ctx->nb_streams > s->nb_streams) {
int i = s->nb_streams;
AVStream *st = avformat_new_stream(s, NULL);
if (!st) {
return AVERROR(ENOMEM);
}
st->id = i;
avcodec_parameters_copy(st->codecpar, sap->sdp_ctx->streams[i]->codecpar);
st->time_base = sap->sdp_ctx->streams[i]->time_base;
}
}
return ret;
}
const AVInputFormat ff_sap_demuxer = {
.name = "sap",
.long_name = NULL_IF_CONFIG_SMALL("SAP input"),
.priv_data_size = sizeof(struct SAPState),
.read_probe = sap_probe,
.read_header = sap_read_header,
.read_packet = sap_fetch_packet,
.read_close = sap_read_close,
.flags = AVFMT_NOFILE,
};