/*

 * 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

 * RTP protocol

 */

#include "libavutil/mem.h"

#include "libavutil/parseutils.h"

#include "libavutil/avstring.h"

#include "libavutil/opt.h"

#include "avformat.h"

#include "internal.h"

#include "rtp.h"

#include "rtpproto.h"

#include "url.h"

#include "ip.h"

#include <stdarg.h>

#include "network.h"

#include "os_support.h"

#include <fcntl.h>

#if HAVE_POLL_H

#include <poll.h>

#endif

typedef struct RTPContext {

    const AVClass *class;

    URLContext *rtp_hd, *rtcp_hd, *fec_hd;

    int rtp_fd, rtcp_fd;

    IPSourceFilters filters;

    int write_to_source;

    struct sockaddr_storage last_rtp_source, last_rtcp_source;

    socklen_t last_rtp_source_len, last_rtcp_source_len;

    int ttl;

    int buffer_size;

    int rtcp_port, local_rtpport, local_rtcpport;

    int connect;

    int pkt_size;

    int dscp;

    char *sources;

    char *block;

    char *fec_options_str;

    int64_t rw_timeout;

    char *localaddr;

} RTPContext;

#define OFFSET(x) offsetof(RTPContext, x)

#define D AV_OPT_FLAG_DECODING_PARAM

#define E AV_OPT_FLAG_ENCODING_PARAM

#define DEPR AV_OPT_FLAG_DEPRECATED

static const AVOption options[] = {

    { "ttl",                "Time to live (multicast only)",                                    OFFSET(ttl),             AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, 255,     .flags = D|E },

    { "buffer_size",        "Send/Receive buffer size (in bytes)",                              OFFSET(buffer_size),     AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "rtcp_port",          "Custom rtcp port",                                                 OFFSET(rtcp_port),       AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "rtcpport",           "Custom rtcp port",                                                 OFFSET(rtcp_port),       AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "local_rtpport",      "Local rtp port",                                                   OFFSET(local_rtpport),   AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "localrtpport",       "Local rtp port",                                                   OFFSET(local_rtpport),   AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "localport",          "Local rtp port",                                                   OFFSET(local_rtpport),   AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E|DEPR },

    { "local_rtcpport",     "Local rtcp port",                                                  OFFSET(local_rtcpport),  AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "localrtcpport",      "Local rtcp port",                                                  OFFSET(local_rtcpport),  AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "connect",            "Connect socket",                                                   OFFSET(connect),         AV_OPT_TYPE_BOOL,   { .i64 =  0 },     0, 1,       .flags = D|E },

    { "write_to_source",    "Send packets to the source address of the latest received packet", OFFSET(write_to_source), AV_OPT_TYPE_BOOL,   { .i64 =  0 },     0, 1,       .flags = D|E },

    { "pkt_size",           "Maximum packet size",                                              OFFSET(pkt_size),        AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "dscp",               "DSCP class",                                                       OFFSET(dscp),            AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },

    { "timeout",            "set timeout (in microseconds) of socket I/O operations",           OFFSET(rw_timeout),      AV_OPT_TYPE_INT64,  { .i64 = -1 },    -1, INT64_MAX, .flags = D|E },

    { "sources",            "Source list",                                                      OFFSET(sources),         AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },

    { "block",              "Block list",                                                       OFFSET(block),           AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },

    { "fec",                "FEC",                                                              OFFSET(fec_options_str), AV_OPT_TYPE_STRING, { .str = NULL },               .flags = E },

    { "localaddr",          "Local address",                                                    OFFSET(localaddr),       AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },

    { NULL }

};

static const AVClass rtp_class = {

    .class_name = "rtp",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

/**

 * 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 h media file context

 * @param uri of the remote server

 * @return zero if no error.

 */

int ff_rtp_set_remote_url(URLContext *h, const char *uri)

{

    RTPContext *s = h->priv_data;

    char hostname[256];

    int port, rtcp_port;

    const char *p;

    char buf[1024];

    char path[1024];

    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,

                 path, sizeof(path), uri);

    rtcp_port = port + 1;

    p = strchr(uri, '?');

    if (p) {

        if (av_find_info_tag(buf, sizeof(buf), "rtcpport", p)) {

            rtcp_port = strtol(buf, NULL, 10);

        }

    }

    ff_url_join(buf, sizeof(buf), "udp", NULL, hostname, port, "%s", path);

    ff_udp_set_remote_url(s->rtp_hd, buf);

    ff_url_join(buf, sizeof(buf), "udp", NULL, hostname, rtcp_port, "%s", path);

    ff_udp_set_remote_url(s->rtcp_hd, buf);

    return 0;

}

static int get_port(const struct sockaddr_storage *ss)

{

    if (ss->ss_family == AF_INET)

        return ntohs(((const struct sockaddr_in *)ss)->sin_port);

#if HAVE_STRUCT_SOCKADDR_IN6

    if (ss->ss_family == AF_INET6)

        return ntohs(((const struct sockaddr_in6 *)ss)->sin6_port);

#endif

    return 0;

}

static void set_port(struct sockaddr_storage *ss, int port)

{

    if (ss->ss_family == AF_INET)

        ((struct sockaddr_in *)ss)->sin_port = htons(port);

#if HAVE_STRUCT_SOCKADDR_IN6

    else if (ss->ss_family == AF_INET6)

        ((struct sockaddr_in6 *)ss)->sin6_port = htons(port);

#endif

}

/**

 * add option to url of the form:

 * "http://host:port/path?option1=val1&option2=val2...

 */

static av_printf_format(3, 4) 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(RTPContext *s,

                          char *buf, int buf_size,

                          const char *hostname,

                          const char *localaddr,

                          int port, int local_port,

                          const char *include_sources,

                          const char *exclude_sources)

{

    ff_url_join(buf, buf_size, "udp", NULL, hostname, port, NULL);

    if (local_port >= 0)

        url_add_option(buf, buf_size, "localport=%d", local_port);

    if (s->ttl >= 0)

        url_add_option(buf, buf_size, "ttl=%d", s->ttl);

    if (s->buffer_size >= 0)

        url_add_option(buf, buf_size, "buffer_size=%d", s->buffer_size);

    if (s->pkt_size >= 0)

        url_add_option(buf, buf_size, "pkt_size=%d", s->pkt_size);

    if (s->connect)

        url_add_option(buf, buf_size, "connect=1");

    if (s->dscp >= 0)

        url_add_option(buf, buf_size, "dscp=%d", s->dscp);

    url_add_option(buf, buf_size, "fifo_size=0");

    if (include_sources && include_sources[0])

        url_add_option(buf, buf_size, "sources=%s", include_sources);

    if (exclude_sources && exclude_sources[0])

        url_add_option(buf, buf_size, "block=%s", exclude_sources);

    if (localaddr && localaddr[0])

        url_add_option(buf, buf_size, "localaddr=%s", localaddr);

}

/**

 * url syntax: rtp://host:port[?option=val...]

 * option: 'ttl=n'            : set the ttl value (for multicast only)

 *         'rtcpport=n'       : set the remote rtcp port to n

 *         'localrtpport=n'   : set the local rtp port to n

 *         'localrtcpport=n'  : set the local rtcp port to n

 *         'pkt_size=n'       : set max packet size

 *         'connect=0/1'      : do a connect() on the UDP socket

 *         'sources=ip[,ip]'  : list allowed source IP addresses

 *         'block=ip[,ip]'    : list disallowed source IP addresses

 *         'write_to_source=0/1' : send packets to the source address of the latest received packet

 *         'dscp=n'           : set DSCP value to n (QoS)

 * deprecated option:

 *         'localport=n'      : set the local port to n

 *

 * if rtcpport isn't set the rtcp port will be the rtp port + 1

 * if local rtp port isn't set any available port will be used for the local

 * rtp and rtcp ports

 * if the local rtcp port is not set it will be the local rtp port + 1

 */

static int rtp_open(URLContext *h, const char *uri, int flags)

{

    RTPContext *s = h->priv_data;

    AVDictionary *fec_opts = NULL;

    int rtp_port;

    char hostname[256];

    char *fec_protocol = NULL;

    char buf[1024];

    char path[1024];

    const char *p;

    int i, max_retry_count = 3;

    int rtcpflags;

    int ret;

    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &rtp_port,

                 path, sizeof(path), uri);

    /* extract parameters */

    if (s->rtcp_port < 0)

        s->rtcp_port = rtp_port + 1;

    p = strchr(uri, '?');

    if (p) {

        ret = ff_parse_opts_from_query_string(s, p, 1);

        if (ret < 0)

            goto fail;

    }

    if (s->sources) {

        if ((ret = ff_ip_parse_sources(h, s->sources, &s->filters)) < 0)

            goto fail;

    }

    if (s->block) {

        if ((ret = ff_ip_parse_blocks(h, s->block, &s->filters)) < 0)

            goto fail;

    }

    if (s->rw_timeout >= 0)

        h->rw_timeout = s->rw_timeout;

    if (s->fec_options_str) {

        p = s->fec_options_str;

        if (!(fec_protocol = av_get_token(&p, "="))) {

            av_log(h, AV_LOG_ERROR, "Failed to parse the FEC protocol value\n");

            ret = AVERROR(EINVAL);

            goto fail;

        }

        if (strcmp(fec_protocol, "prompeg")) {

            av_log(h, AV_LOG_ERROR, "Unsupported FEC protocol %s\n", fec_protocol);

            ret = AVERROR(EINVAL);

            goto fail;

        }

        p = s->fec_options_str + strlen(fec_protocol);

        while (*p && *p == '=') p++;

        if (av_dict_parse_string(&fec_opts, p, "=", ":", 0) < 0) {

            av_log(h, AV_LOG_ERROR, "Failed to parse the FEC options\n");

            ret = AVERROR(EINVAL);

            goto fail;

        }

        if (s->ttl > 0) {

            av_dict_set_int(&fec_opts, "ttl", s->ttl, 0);

        }

    }

    for (i = 0; i < max_retry_count; i++) {

        const char *sources = s->sources ? s->sources : "";

        const char *block = s->block ? s->block : "";

        build_udp_url(s, buf, sizeof(buf),

                      hostname, s->localaddr, rtp_port, s->local_rtpport,

                      sources, block);

        ret = ffurl_open_whitelist(&s->rtp_hd, buf, flags, &h->interrupt_callback,

                                   NULL, h->protocol_whitelist, h->protocol_blacklist, h);

        if (ret < 0)

            goto fail;

        s->local_rtpport = ff_udp_get_local_port(s->rtp_hd);

        if(s->local_rtpport == 65535) {

            s->local_rtpport = -1;

            continue;

        }

        rtcpflags = flags | AVIO_FLAG_WRITE;

        if (s->local_rtcpport < 0) {

            s->local_rtcpport = s->local_rtpport + 1;

            build_udp_url(s, buf, sizeof(buf),

                          hostname, s->localaddr, s->rtcp_port, s->local_rtcpport,

                          sources, block);

            if (ffurl_open_whitelist(&s->rtcp_hd, buf, rtcpflags,

                                     &h->interrupt_callback, NULL,

                                     h->protocol_whitelist, h->protocol_blacklist, h) < 0) {

                s->local_rtpport = s->local_rtcpport = -1;

                continue;

            }

            break;

        }

        build_udp_url(s, buf, sizeof(buf),

                      hostname, s->localaddr, s->rtcp_port, s->local_rtcpport,

                      sources, block);

        ret = ffurl_open_whitelist(&s->rtcp_hd, buf, rtcpflags, &h->interrupt_callback,

                                   NULL, h->protocol_whitelist, h->protocol_blacklist, h);

        if (ret < 0)

            goto fail;

        break;

    }

    s->fec_hd = NULL;

    if (fec_protocol) {

        ff_url_join(buf, sizeof(buf), fec_protocol, NULL, hostname, rtp_port, NULL);

        ret = ffurl_open_whitelist(&s->fec_hd, buf, flags, &h->interrupt_callback,

                                   &fec_opts, h->protocol_whitelist, h->protocol_blacklist, h);

        if (ret < 0)

            goto fail;

    }

    /* just to ease handle access. XXX: need to suppress direct handle

       access */

    s->rtp_fd = ffurl_get_file_handle(s->rtp_hd);

    s->rtcp_fd = ffurl_get_file_handle(s->rtcp_hd);

    h->max_packet_size = s->rtp_hd->max_packet_size;

    h->is_streamed = 1;

    av_free(fec_protocol);

    av_dict_free(&fec_opts);

    return 0;

 fail:

    ff_ip_reset_filters(&s->filters);

    ffurl_closep(&s->rtp_hd);

    ffurl_closep(&s->rtcp_hd);

    ffurl_closep(&s->fec_hd);

    av_free(fec_protocol);

    av_dict_free(&fec_opts);

    return ret;

}

static int rtp_read(URLContext *h, uint8_t *buf, int size)

{

    RTPContext *s = h->priv_data;

    int len, n, i;

    struct pollfd p[2] = {{s->rtp_fd, POLLIN, 0}, {s->rtcp_fd, POLLIN, 0}};

    int poll_delay = h->flags & AVIO_FLAG_NONBLOCK ? 0 : POLLING_TIME;

    struct sockaddr_storage *addrs[2] = { &s->last_rtp_source, &s->last_rtcp_source };

    socklen_t *addr_lens[2] = { &s->last_rtp_source_len, &s->last_rtcp_source_len };

    int runs = h->rw_timeout / 1000 / POLLING_TIME;

    for(;;) {

        if (ff_check_interrupt(&h->interrupt_callback))

            return AVERROR_EXIT;

        n = poll(p, 2, poll_delay);

        if (n > 0) {

            /* first try RTCP, then RTP */

            for (i = 1; i >= 0; i--) {

                if (!(p[i].revents & POLLIN))

                    continue;

                *addr_lens[i] = sizeof(*addrs[i]);

                len = recvfrom(p[i].fd, buf, size, 0,

                                (struct sockaddr *)addrs[i], addr_lens[i]);

                if (len < 0) {

                    if (ff_neterrno() == AVERROR(EAGAIN) ||

                        ff_neterrno() == AVERROR(EINTR))

                        continue;

                    return AVERROR(EIO);

                }

                if (ff_ip_check_source_lists(addrs[i], &s->filters))

                    continue;

                return len;

            }

        } else if (n == 0 && h->rw_timeout > 0 && --runs <= 0) {

            return AVERROR(ETIMEDOUT);

        } else if (n < 0) {

            if (ff_neterrno() == AVERROR(EINTR))

                continue;

            return AVERROR(EIO);

        }

        if (h->flags & AVIO_FLAG_NONBLOCK)

            return AVERROR(EAGAIN);

    }

}

static int rtp_write(URLContext *h, const uint8_t *buf, int size)

{

    RTPContext *s = h->priv_data;

    int ret, ret_fec;

    URLContext *hd;

    if (size < 2)

        return AVERROR(EINVAL);

    if ((buf[0] & 0xc0) != (RTP_VERSION << 6))

        av_log(h, AV_LOG_WARNING, "Data doesn't look like RTP packets, "

                                  "make sure the RTP muxer is used\n");

    if (s->write_to_source) {

        int fd;

        struct sockaddr_storage *source, temp_source;

        socklen_t *source_len, temp_len;

        if (!s->last_rtp_source.ss_family && !s->last_rtcp_source.ss_family) {

            av_log(h, AV_LOG_ERROR,

                   "Unable to send packet to source, no packets received yet\n");

            // Intentionally not returning an error here

            return size;

        }

        if (RTP_PT_IS_RTCP(buf[1])) {

            fd = s->rtcp_fd;

            source     = &s->last_rtcp_source;

            source_len = &s->last_rtcp_source_len;

        } else {

            fd = s->rtp_fd;

            source     = &s->last_rtp_source;

            source_len = &s->last_rtp_source_len;

        }

        if (!source->ss_family) {

            source      = &temp_source;

            source_len  = &temp_len;

            if (RTP_PT_IS_RTCP(buf[1])) {

                temp_source = s->last_rtp_source;

                temp_len    = s->last_rtp_source_len;

                set_port(source, get_port(source) + 1);

                av_log(h, AV_LOG_INFO,

                       "Not received any RTCP packets yet, inferring peer port "

                       "from the RTP port\n");

            } else {

                temp_source = s->last_rtcp_source;

                temp_len    = s->last_rtcp_source_len;

                set_port(source, get_port(source) - 1);

                av_log(h, AV_LOG_INFO,

                       "Not received any RTP packets yet, inferring peer port "

                       "from the RTCP port\n");

            }

        }

        if (!(h->flags & AVIO_FLAG_NONBLOCK)) {

            ret = ff_network_wait_fd(fd, 1);

            if (ret < 0)

                return ret;

        }

        ret = sendto(fd, buf, size, 0, (struct sockaddr *) source,

                     *source_len);

        return ret < 0 ? ff_neterrno() : ret;

    }

    if (RTP_PT_IS_RTCP(buf[1])) {

        /* RTCP payload type */

        hd = s->rtcp_hd;

    } else {

        /* RTP payload type */

        hd = s->rtp_hd;

    }

    if ((ret = ffurl_write(hd, buf, size)) < 0) {

        return ret;

    }

    if (s->fec_hd && !RTP_PT_IS_RTCP(buf[1])) {

        if ((ret_fec = ffurl_write(s->fec_hd, buf, size)) < 0) {

            av_log(h, AV_LOG_ERROR, "Failed to send FEC\n");

            return ret_fec;

        }

    }

    return ret;

}

static int rtp_close(URLContext *h)

{

    RTPContext *s = h->priv_data;

    ff_ip_reset_filters(&s->filters);

    ffurl_closep(&s->rtp_hd);

    ffurl_closep(&s->rtcp_hd);

    ffurl_closep(&s->fec_hd);

    return 0;

}

/**

 * Return the local rtp port used by the RTP connection

 * @param h media file context

 * @return the local port number

 */

int ff_rtp_get_local_rtp_port(URLContext *h)

{

    RTPContext *s = h->priv_data;

    return ff_udp_get_local_port(s->rtp_hd);

}

/**

 * Return the local rtcp port used by the RTP connection

 * @param h media file context

 * @return the local port number

 */

static int rtp_get_file_handle(URLContext *h)

{

    RTPContext *s = h->priv_data;

    return s->rtp_fd;

}

static int rtp_get_multi_file_handle(URLContext *h, int **handles,

                                     int *numhandles)

{

    RTPContext *s = h->priv_data;

    int *hs       = *handles = av_malloc(sizeof(**handles) * 2);

    if (!hs)

        return AVERROR(ENOMEM);

    hs[0] = s->rtp_fd;

    hs[1] = s->rtcp_fd;

    *numhandles = 2;

    return 0;

}

const URLProtocol ff_rtp_protocol = {

    .name                      = "rtp",

    .url_open                  = rtp_open,

    .url_read                  = rtp_read,

    .url_write                 = rtp_write,

    .url_close                 = rtp_close,

    .url_get_file_handle       = rtp_get_file_handle,

    .url_get_multi_file_handle = rtp_get_multi_file_handle,

    .priv_data_size            = sizeof(RTPContext),

    .flags                     = URL_PROTOCOL_FLAG_NETWORK,

    .priv_data_class           = &rtp_class,

};