/* * RTP network protocol * Copyright (c) 2002 Fabrice Bellard. * * 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 *//** * @file rtpproto.c * RTP protocol */#include "libavutil/avstring.h"#include "avformat.h"#include <unistd.h>#include <stdarg.h>#include "network.h"#include "os_support.h"#include <fcntl.h>#define RTP_TX_BUF_SIZE  (64 * 1024)#define RTP_RX_BUF_SIZE  (128 * 1024)typedef struct RTPContext {    URLContext *rtp_hd, *rtcp_hd;    int rtp_fd, rtcp_fd;} RTPContext;/** * If no filename is given to av_open_input_file because you want to * get the local port first, then you must call this function to set * the remote server address. * * @param s1 media file context * @param uri of the remote server * @return zero if no error. */int rtp_set_remote_url(URLContext *h, const char *uri){    RTPContext *s = h->priv_data;    char hostname[256];    int port;    char buf[1024];    char path[1024];    url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,              path, sizeof(path), uri);    snprintf(buf, sizeof(buf), "udp://%s:%d%s", hostname, port, path);    udp_set_remote_url(s->rtp_hd, buf);    snprintf(buf, sizeof(buf), "udp://%s:%d%s", hostname, port + 1, path);    udp_set_remote_url(s->rtcp_hd, buf);    return 0;}/** * add option to url of the form: * "http://host:port/path?option1=val1&option2=val2... */static void url_add_option(char *buf, int buf_size, const char *fmt, ...){    char buf1[1024];    va_list ap;    va_start(ap, fmt);    if (strchr(buf, '?'))        av_strlcat(buf, "&", buf_size);    else        av_strlcat(buf, "?", buf_size);    vsnprintf(buf1, sizeof(buf1), fmt, ap);    av_strlcat(buf, buf1, buf_size);    va_end(ap);}static void build_udp_url(char *buf, int buf_size,                          const char *hostname, int port,                          int local_port, int ttl,                          int max_packet_size){    snprintf(buf, buf_size, "udp://%s:%d", hostname, port);    if (local_port >= 0)        url_add_option(buf, buf_size, "localport=%d", local_port);    if (ttl >= 0)        url_add_option(buf, buf_size, "ttl=%d", ttl);    if (max_packet_size >=0)        url_add_option(buf, buf_size, "pkt_size=%d", max_packet_size);}/** * url syntax: rtp://host:port[?option=val...] * option: 'ttl=n'       : set the ttl value (for multicast only) *         'localport=n' : set the local port to n *         'pkt_size=n'  : set max packet size * */static int rtp_open(URLContext *h, const char *uri, int flags){    RTPContext *s;    int port, is_output, ttl, local_port, max_packet_size;    char hostname[256];    char buf[1024];    char path[1024];    const char *p;    is_output = (flags & URL_WRONLY);    s = av_mallocz(sizeof(RTPContext));    if (!s)        return AVERROR(ENOMEM);    h->priv_data = s;    url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,              path, sizeof(path), uri);    /* extract parameters */    ttl = -1;    local_port = -1;    max_packet_size = -1;    p = strchr(uri, '?');    if (p) {        if (find_info_tag(buf, sizeof(buf), "ttl", p)) {            ttl = strtol(buf, NULL, 10);        }        if (find_info_tag(buf, sizeof(buf), "localport", p)) {            local_port = strtol(buf, NULL, 10);        }        if (find_info_tag(buf, sizeof(buf), "pkt_size", p)) {            max_packet_size = strtol(buf, NULL, 10);        }    }    build_udp_url(buf, sizeof(buf),                  hostname, port, local_port, ttl, max_packet_size);    if (url_open(&s->rtp_hd, buf, flags) < 0)        goto fail;    local_port = udp_get_local_port(s->rtp_hd);    /* XXX: need to open another connection if the port is not even */    /* well, should suppress localport in path */    build_udp_url(buf, sizeof(buf),                  hostname, port + 1, local_port + 1, ttl, max_packet_size);    if (url_open(&s->rtcp_hd, buf, flags) < 0)        goto fail;    /* just to ease handle access. XXX: need to suppress direct handle       access */    s->rtp_fd = udp_get_file_handle(s->rtp_hd);    s->rtcp_fd = udp_get_file_handle(s->rtcp_hd);    h->max_packet_size = url_get_max_packet_size(s->rtp_hd);    h->is_streamed = 1;    return 0; fail:    if (s->rtp_hd)        url_close(s->rtp_hd);    if (s->rtcp_hd)        url_close(s->rtcp_hd);    av_free(s);    return AVERROR(EIO);}static int rtp_read(URLContext *h, uint8_t *buf, int size){    RTPContext *s = h->priv_data;    struct sockaddr_in from;    socklen_t from_len;    int len, fd_max, n;    fd_set rfds;#if 0    for(;;) {        from_len = sizeof(from);        len = recvfrom (s->rtp_fd, buf, size, 0,                        (struct sockaddr *)&from, &from_len);        if (len < 0) {            if (ff_neterrno() == FF_NETERROR(EAGAIN) ||                ff_neterrno() == FF_NETERROR(EINTR))                continue;            return AVERROR(EIO);        }        break;    }#else    for(;;) {        /* build fdset to listen to RTP and RTCP packets */        FD_ZERO(&rfds);        fd_max = s->rtp_fd;        FD_SET(s->rtp_fd, &rfds);        if (s->rtcp_fd > fd_max)            fd_max = s->rtcp_fd;        FD_SET(s->rtcp_fd, &rfds);        n = select(fd_max + 1, &rfds, NULL, NULL, NULL);        if (n > 0) {            /* first try RTCP */            if (FD_ISSET(s->rtcp_fd, &rfds)) {                from_len = sizeof(from);                len = recvfrom (s->rtcp_fd, buf, size, 0,                                (struct sockaddr *)&from, &from_len);                if (len < 0) {                    if (ff_neterrno() == FF_NETERROR(EAGAIN) ||                        ff_neterrno() == FF_NETERROR(EINTR))                        continue;                    return AVERROR(EIO);                }                break;            }            /* then RTP */            if (FD_ISSET(s->rtp_fd, &rfds)) {                from_len = sizeof(from);                len = recvfrom (s->rtp_fd, buf, size, 0,                                (struct sockaddr *)&from, &from_len);                if (len < 0) {                    if (ff_neterrno() == FF_NETERROR(EAGAIN) ||                        ff_neterrno() == FF_NETERROR(EINTR))                        continue;                    return AVERROR(EIO);                }                break;            }        }    }#endif    return len;}static int rtp_write(URLContext *h, uint8_t *buf, int size){    RTPContext *s = h->priv_data;    int ret;    URLContext *hd;    if (buf[1] >= 200 && buf[1] <= 204) {        /* RTCP payload type */        hd = s->rtcp_hd;    } else {        /* RTP payload type */        hd = s->rtp_hd;    }    ret = url_write(hd, buf, size);#if 0    {        struct timespec ts;        ts.tv_sec = 0;        ts.tv_nsec = 10 * 1000000;        nanosleep(&ts, NULL);    }#endif    return ret;}static int rtp_close(URLContext *h){    RTPContext *s = h->priv_data;    url_close(s->rtp_hd);    url_close(s->rtcp_hd);    av_free(s);    return 0;}/** * Return the local port used by the RTP connection * @param s1 media file context * @return the local port number */int rtp_get_local_port(URLContext *h){    RTPContext *s = h->priv_data;    return udp_get_local_port(s->rtp_hd);}/** * Return the rtp and rtcp file handles for select() usage to wait for * several RTP streams at the same time. * @param h media file context */void rtp_get_file_handles(URLContext *h, int *prtp_fd, int *prtcp_fd){    RTPContext *s = h->priv_data;    *prtp_fd = s->rtp_fd;    *prtcp_fd = s->rtcp_fd;}URLProtocol rtp_protocol = {    "rtp",    rtp_open,    rtp_read,    rtp_write,    NULL, /* seek */    rtp_close,};