rtsp.c

ffmpeg源码分析

        /* get the content */
        q = buf;
        while (*p != '\n' && *p != '\r' && *p != '\0') {
            if ((q - buf) < sizeof(buf) - 1)
                *q++ = *p;
            p++;
        }
        *q = '\0';
        sdp_parse_line(s, s1, letter, buf);
    next_line:
        while (*p != '\n' && *p != '\0')
            p++;
        if (*p == '\n')
            p++;
    }
    return 0;
}

static void rtsp_parse_range(int *min_ptr, int *max_ptr, const char **pp)
{
    const char *p;
    int v;

    p = *pp;
    skip_spaces(&p);
    v = strtol(p, (char **)&p, 10);
    if (*p == '-') {
        p++;
        *min_ptr = v;
        v = strtol(p, (char **)&p, 10);
        *max_ptr = v;
    } else {
        *min_ptr = v;
        *max_ptr = v;
    }
    *pp = p;
}

/* XXX: only one transport specification is parsed */
static void rtsp_parse_transport(RTSPHeader *reply, const char *p)
{
    char transport_protocol[16];
    char profile[16];
    char lower_transport[16];
    char parameter[16];
    RTSPTransportField *th;
    char buf[256];

    reply->nb_transports = 0;

    for(;;) {
        skip_spaces(&p);
        if (*p == '\0')
            break;

        th = &reply->transports[reply->nb_transports];

        get_word_sep(transport_protocol, sizeof(transport_protocol),
                     "/", &p);
        if (*p == '/')
            p++;
        get_word_sep(profile, sizeof(profile), "/;,", &p);
        lower_transport[0] = '\0';
        if (*p == '/') {
            p++;
            get_word_sep(lower_transport, sizeof(lower_transport),
                         ";,", &p);
        }
        if (!strcasecmp(lower_transport, "TCP"))
            th->protocol = RTSP_PROTOCOL_RTP_TCP;
        else
            th->protocol = RTSP_PROTOCOL_RTP_UDP;

        if (*p == ';')
            p++;
        /* get each parameter */
        while (*p != '\0' && *p != ',') {
            get_word_sep(parameter, sizeof(parameter), "=;,", &p);
            if (!strcmp(parameter, "port")) {
                if (*p == '=') {
                    p++;
                    rtsp_parse_range(&th->port_min, &th->port_max, &p);
                }
            } else if (!strcmp(parameter, "client_port")) {
                if (*p == '=') {
                    p++;
                    rtsp_parse_range(&th->client_port_min,
                                     &th->client_port_max, &p);
                }
            } else if (!strcmp(parameter, "server_port")) {
                if (*p == '=') {
                    p++;
                    rtsp_parse_range(&th->server_port_min,
                                     &th->server_port_max, &p);
                }
            } else if (!strcmp(parameter, "interleaved")) {
                if (*p == '=') {
                    p++;
                    rtsp_parse_range(&th->interleaved_min,
                                     &th->interleaved_max, &p);
                }
            } else if (!strcmp(parameter, "multicast")) {
                if (th->protocol == RTSP_PROTOCOL_RTP_UDP)
                    th->protocol = RTSP_PROTOCOL_RTP_UDP_MULTICAST;
            } else if (!strcmp(parameter, "ttl")) {
                if (*p == '=') {
                    p++;
                    th->ttl = strtol(p, (char **)&p, 10);
                }
            } else if (!strcmp(parameter, "destination")) {
                struct in_addr ipaddr;

                if (*p == '=') {
                    p++;
                    get_word_sep(buf, sizeof(buf), ";,", &p);
                    if (inet_aton(buf, &ipaddr))
                        th->destination = ntohl(ipaddr.s_addr);
                }
            }
            while (*p != ';' && *p != '\0' && *p != ',')
                p++;
            if (*p == ';')
                p++;
        }
        if (*p == ',')
            p++;

        reply->nb_transports++;
    }
}

static void rtsp_parse_range_npt(RTSPHeader *reply, const char *p)
{
    char buf[256];

    skip_spaces(&p);
    if (!stristart(p, "npt=", &p))
        return;

    reply->range_start = AV_NOPTS_VALUE;
    reply->range_end = AV_NOPTS_VALUE;

    get_word_sep(buf, sizeof(buf), "-", &p);
    reply->range_start = parse_date(buf, 1);
    if (*p == '-') {
        p++;
        get_word_sep(buf, sizeof(buf), "-", &p);
        reply->range_end = parse_date(buf, 1);
    }
}

void rtsp_parse_line(RTSPHeader *reply, const char *buf)
{
    const char *p;

    /* NOTE: we do case independent match for broken servers */
    p = buf;
    if (stristart(p, "Session:", &p)) {
        get_word_sep(reply->session_id, sizeof(reply->session_id), ";", &p);
    } else if (stristart(p, "Content-Length:", &p)) {
        reply->content_length = strtol(p, NULL, 10);
    } else if (stristart(p, "Transport:", &p)) {
        rtsp_parse_transport(reply, p);
    } else if (stristart(p, "CSeq:", &p)) {
        reply->seq = strtol(p, NULL, 10);
    } else if (stristart(p, "Range:", &p)) {
        rtsp_parse_range_npt(reply, p);
    }
}

static int url_readbuf(URLContext *h, unsigned char *buf, int size)
{
    int ret, len;

    len = 0;
    while (len < size) {
        ret = url_read(h, buf+len, size-len);
        if (ret < 1)
            return ret;
        len += ret;
    }
    return len;
}

/* skip a RTP/TCP interleaved packet */
static void rtsp_skip_packet(AVFormatContext *s)
{
    RTSPState *rt = s->priv_data;
    int ret, len, len1;
    uint8_t buf[1024];

    ret = url_readbuf(rt->rtsp_hd, buf, 3);
    if (ret != 3)
        return;
    len = (buf[1] << 8) | buf[2];
#ifdef DEBUG
    printf("skipping RTP packet len=%d\n", len);
#endif
    /* skip payload */
    while (len > 0) {
        len1 = len;
        if (len1 > sizeof(buf))
            len1 = sizeof(buf);
        ret = url_readbuf(rt->rtsp_hd, buf, len1);
        if (ret != len1)
            return;
        len -= len1;
    }
}

static void rtsp_send_cmd(AVFormatContext *s,
                          const char *cmd, RTSPHeader *reply,
                          unsigned char **content_ptr)
{
    RTSPState *rt = s->priv_data;
    char buf[4096], buf1[1024], *q;
    unsigned char ch;
    const char *p;
    int content_length, line_count;
    unsigned char *content = NULL;

    memset(reply, 0, sizeof(RTSPHeader));

    rt->seq++;
    pstrcpy(buf, sizeof(buf), cmd);
    snprintf(buf1, sizeof(buf1), "CSeq: %d\r\n", rt->seq);
    pstrcat(buf, sizeof(buf), buf1);
    if (rt->session_id[0] != '\0' && !strstr(cmd, "\nIf-Match:")) {
        snprintf(buf1, sizeof(buf1), "Session: %s\r\n", rt->session_id);
        pstrcat(buf, sizeof(buf), buf1);
    }
    pstrcat(buf, sizeof(buf), "\r\n");
#ifdef DEBUG
    printf("Sending:\n%s--\n", buf);
#endif
    url_write(rt->rtsp_hd, buf, strlen(buf));

    /* parse reply (XXX: use buffers) */
    line_count = 0;
    rt->last_reply[0] = '\0';
    for(;;) {
        q = buf;
        for(;;) {
            if (url_readbuf(rt->rtsp_hd, &ch, 1) != 1)
                break;
            if (ch == '\n')
                break;
            if (ch == '$') {
                /* XXX: only parse it if first char on line ? */
                rtsp_skip_packet(s);
            } else if (ch != '\r') {
                if ((q - buf) < sizeof(buf) - 1)
                    *q++ = ch;
            }
        }
        *q = '\0';
#ifdef DEBUG
        printf("line='%s'\n", buf);
#endif
        /* test if last line */
        if (buf[0] == '\0')
            break;
        p = buf;
        if (line_count == 0) {
            /* get reply code */
            get_word(buf1, sizeof(buf1), &p);
            get_word(buf1, sizeof(buf1), &p);
            reply->status_code = atoi(buf1);
        } else {
            rtsp_parse_line(reply, p);
            pstrcat(rt->last_reply, sizeof(rt->last_reply), p);
            pstrcat(rt->last_reply, sizeof(rt->last_reply), "\n");
        }
        line_count++;
    }

    if (rt->session_id[0] == '\0' && reply->session_id[0] != '\0')
        pstrcpy(rt->session_id, sizeof(rt->session_id), reply->session_id);

    content_length = reply->content_length;
    if (content_length > 0) {
        /* leave some room for a trailing '\0' (useful for simple parsing) */
        content = av_malloc(content_length + 1);
        (void)url_readbuf(rt->rtsp_hd, content, content_length);
        content[content_length] = '\0';
    }
    if (content_ptr)
        *content_ptr = content;
}

/* useful for modules: set RTSP callback function */

void rtsp_set_callback(FFRTSPCallback *rtsp_cb)
{
    ff_rtsp_callback = rtsp_cb;
}


/* close and free RTSP streams */
static void rtsp_close_streams(RTSPState *rt)
{
    int i;
    RTSPStream *rtsp_st;

    for(i=0;i<rt->nb_rtsp_streams;i++) {
        rtsp_st = rt->rtsp_streams[i];
        if (rtsp_st) {
            if (rtsp_st->rtp_ctx)
                rtp_parse_close(rtsp_st->rtp_ctx);
            if (rtsp_st->rtp_handle)
                url_close(rtsp_st->rtp_handle);
        }
        av_free(rtsp_st);
    }
    av_free(rt->rtsp_streams);
}

static int rtsp_read_header(AVFormatContext *s,
                            AVFormatParameters *ap)
{
    RTSPState *rt = s->priv_data;
    char host[1024], path[1024], tcpname[1024], cmd[2048];
    URLContext *rtsp_hd;
    int port, i, j, ret, err;
    RTSPHeader reply1, *reply = &reply1;
    unsigned char *content = NULL;
    RTSPStream *rtsp_st;
    int protocol_mask;
    AVStream *st;

    /* extract hostname and port */
    url_split(NULL, 0, NULL, 0,
              host, sizeof(host), &port, path, sizeof(path), s->filename);
    if (port < 0)
        port = RTSP_DEFAULT_PORT;

    /* open the tcp connexion */
    snprintf(tcpname, sizeof(tcpname), "tcp://%s:%d", host, port);
    if (url_open(&rtsp_hd, tcpname, URL_RDWR) < 0)
        return AVERROR_IO;
    rt->rtsp_hd = rtsp_hd;
    rt->seq = 0;

    /* describe the stream */
    snprintf(cmd, sizeof(cmd),
             "DESCRIBE %s RTSP/1.0\r\n"
             "Accept: application/sdp\r\n",
             s->filename);
    rtsp_send_cmd(s, cmd, reply, &content);
    if (!content) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }
    if (reply->status_code != RTSP_STATUS_OK) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }

    /* now we got the SDP description, we parse it */
    ret = sdp_parse(s, (const char *)content);
    av_freep(&content);
    if (ret < 0) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }

    protocol_mask = rtsp_default_protocols;

    /* for each stream, make the setup request */
    /* XXX: we assume the same server is used for the control of each
       RTSP stream */

    for(j = RTSP_RTP_PORT_MIN, i = 0; i < rt->nb_rtsp_streams; ++i) {
        char transport[2048];

        rtsp_st = rt->rtsp_streams[i];

        /* compute available transports */
        transport[0] = '\0';

        /* RTP/UDP */
        if (protocol_mask & (1 << RTSP_PROTOCOL_RTP_UDP)) {
            char buf[256];

            /* first try in specified port range */
            if (RTSP_RTP_PORT_MIN != 0) {
                while(j <= RTSP_RTP_PORT_MAX) {
                    snprintf(buf, sizeof(buf), "rtp://?localport=%d", j);
                    if (url_open(&rtsp_st->rtp_handle, buf, URL_RDONLY) == 0) {
                        j += 2; /* we will use two port by rtp stream (rtp and rtcp) */
                        goto rtp_opened;
                    }
                }
            }

/*            then try on any port
**            if (url_open(&rtsp_st->rtp_handle, "rtp://", URL_RDONLY) < 0) {
**                err = AVERROR_INVALIDDATA;
**                goto fail;
**            }
*/

        rtp_opened:
            port = rtp_get_local_port(rtsp_st->rtp_handle);
            if (transport[0] != '\0')
                pstrcat(transport, sizeof(transport), ",");
            snprintf(transport + strlen(transport), sizeof(transport) - strlen(transport) - 1,
                     "RTP/AVP/UDP;unicast;client_port=%d-%d",
                     port, port + 1);
        }

        /* RTP/TCP */
        else if (protocol_mask & (1 << RTSP_PROTOCOL_RTP_TCP)) {
            if (transport[0] != '\0')
                pstrcat(transport, sizeof(transport), ",");
            snprintf(transport + strlen(transport), sizeof(transport) - strlen(transport) - 1,
                     "RTP/AVP/TCP");
        }

        else if (protocol_mask & (1 << RTSP_PROTOCOL_RTP_UDP_MULTICAST)) {
            if (transport[0] != '\0')
                pstrcat(transport, sizeof(transport), ",");
            snprintf(transport + strlen(transport),
                     sizeof(transport) - strlen(transport) - 1,
                     "RTP/AVP/UDP;multicast");
        }
        snprintf(cmd, sizeof(cmd),
                 "SETUP %s RTSP/1.0\r\n"
                 "Transport: %s\r\n",
                 rtsp_st->control_url, transport);
        rtsp_send_cmd(s, cmd, reply, NULL);
        if (reply->status_code != RTSP_STATUS_OK ||
            reply->nb_transports != 1) {
            err = AVERROR_INVALIDDATA;
            goto fail;
        }

        /* XXX: same protocol for all streams is required */
        if (i > 0) {
            if (reply->transports[0].protocol != rt->protocol) {
                err = AVERROR_INVALIDDATA;
                goto fail;
            }
        } else {
            rt->protocol = reply->transports[0].protocol;
        }

        /* close RTP connection if not choosen */
        if (reply->transports[0].protocol != RTSP_PROTOCOL_RTP_UDP &&
            (protocol_mask & (1 << RTSP_PROTOCOL_RTP_UDP))) {
            url_close(rtsp_st->rtp_handle);
            rtsp_st->rtp_handle = NULL;
        }

        switch(reply->transports[0].protocol) {
        case RTSP_PROTOCOL_RTP_TCP:
            rtsp_st->interleaved_min = reply->transports[0].interleaved_min;
            rtsp_st->interleaved_max = reply->transports[0].interleaved_max;
            break;

        case RTSP_PROTOCOL_RTP_UDP:
            {
                char url[1024];

                /* XXX: also use address if specified */
                snprintf(url, sizeof(url), "rtp://%s:%d",
                         host, reply->transports[0].server_port_min);
                if (rtp_set_remote_url(rtsp_st->rtp_handle, url) < 0) {
                    err = AVERROR_INVALIDDATA;
                    goto fail;
                }
            }
            break;
        case RTSP_PROTOCOL_RTP_UDP_MULTICAST:
            {
                char url[1024];
                int ttl;