/**
 * @file rtp.c
 * @brief Real-Time Protocol (RTP) demux module for VLC media player
 */
/*****************************************************************************
 * Copyright (C) 2001-2005 VLC authors and VideoLAN
 * Copyright © 2007-2009 Rémi Denis-Courmont
 *
 * This library 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.
 *
 * This library 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 this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 ****************************************************************************/

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdarg.h>
#include <assert.h>

#include <vlc_common.h>
#include <vlc_demux.h>
#include <vlc_network.h>
#include <vlc_plugin.h>
#include <vlc_dialog.h>
#include <vlc_aout.h> /* aout_FormatPrepare() */

#include "rtp.h"
#ifdef HAVE_SRTP
# include <srtp.h>
# include <gcrypt.h>
# include <vlc_gcrypt.h>
#endif

#define RTCP_PORT_TEXT N_("RTCP (local) port")
#define RTCP_PORT_LONGTEXT N_( \
    "RTCP packets will be received on this transport protocol port. " \
    "If zero, multiplexed RTP/RTCP is used.")

#define SRTP_KEY_TEXT N_("SRTP key (hexadecimal)")
#define SRTP_KEY_LONGTEXT N_( \
    "RTP packets will be authenticated and deciphered "\
    "with this Secure RTP master shared secret key. "\
    "This must be a 32-character-long hexadecimal string.")

#define SRTP_SALT_TEXT N_("SRTP salt (hexadecimal)")
#define SRTP_SALT_LONGTEXT N_( \
    "Secure RTP requires a (non-secret) master salt value. " \
    "This must be a 28-character-long hexadecimal string.")

#define RTP_MAX_SRC_TEXT N_("Maximum RTP sources")
#define RTP_MAX_SRC_LONGTEXT N_( \
    "How many distinct active RTP sources are allowed at a time." )

#define RTP_TIMEOUT_TEXT N_("RTP source timeout (sec)")
#define RTP_TIMEOUT_LONGTEXT N_( \
    "How long to wait for any packet before a source is expired.")

#define RTP_MAX_DROPOUT_TEXT N_("Maximum RTP sequence number dropout")
#define RTP_MAX_DROPOUT_LONGTEXT N_( \
    "RTP packets will be discarded if they are too much ahead (i.e. in the " \
    "future) by this many packets from the last received packet." )

#define RTP_MAX_MISORDER_TEXT N_("Maximum RTP sequence number misordering")
#define RTP_MAX_MISORDER_LONGTEXT N_( \
    "RTP packets will be discarded if they are too far behind (i.e. in the " \
    "past) by this many packets from the last received packet." )

#define RTP_DYNAMIC_PT_TEXT N_("RTP payload format assumed for dynamic " \
                               "payloads")
#define RTP_DYNAMIC_PT_LONGTEXT N_( \
    "This payload format will be assumed for dynamic payload types " \
    "(between 96 and 127) if it can't be determined otherwise with " \
    "out-of-band mappings (SDP)" )

static const char *const dynamic_pt_list[] = { "theora" };
static const char *const dynamic_pt_list_text[] = { "Theora Encoded Video" };

static int  Open (vlc_object_t *);
static void Close (vlc_object_t *);

/*
 * Module descriptor
 */
vlc_module_begin ()
    set_shortname (N_("RTP"))
    set_description (N_("Real-Time Protocol (RTP) input"))
    set_category (CAT_INPUT)
    set_subcategory (SUBCAT_INPUT_DEMUX)
    set_capability ("access_demux", 0)
    set_callbacks (Open, Close)

    add_integer ("rtcp-port", 0, RTCP_PORT_TEXT,
                 RTCP_PORT_LONGTEXT, false)
        change_integer_range (0, 65535)
        change_safe ()
#ifdef HAVE_SRTP
    add_string ("srtp-key", "",
                SRTP_KEY_TEXT, SRTP_KEY_LONGTEXT, false)
        change_safe ()
    add_string ("srtp-salt", "",
                SRTP_SALT_TEXT, SRTP_SALT_LONGTEXT, false)
        change_safe ()
#endif
    add_integer ("rtp-max-src", 1, RTP_MAX_SRC_TEXT,
                 RTP_MAX_SRC_LONGTEXT, true)
        change_integer_range (1, 255)
    add_integer ("rtp-timeout", 5, RTP_TIMEOUT_TEXT,
                 RTP_TIMEOUT_LONGTEXT, true)
    add_integer ("rtp-max-dropout", 3000, RTP_MAX_DROPOUT_TEXT,
                 RTP_MAX_DROPOUT_LONGTEXT, true)
        change_integer_range (0, 32767)
    add_integer ("rtp-max-misorder", 100, RTP_MAX_MISORDER_TEXT,
                 RTP_MAX_MISORDER_LONGTEXT, true)
        change_integer_range (0, 32767)
    add_string ("rtp-dynamic-pt", NULL, RTP_DYNAMIC_PT_TEXT,
                RTP_DYNAMIC_PT_LONGTEXT, true)
        change_string_list (dynamic_pt_list, dynamic_pt_list_text)

    /*add_shortcut ("sctp")*/
    add_shortcut ("dccp", "rtptcp", /* "tcp" is already taken :( */
                  "rtp", "udplite")
vlc_module_end ()

/*
 * TODO: so much stuff
 * - send RTCP-RR and RTCP-BYE
 * - dynamic payload types (need SDP parser)
 * - multiple medias (need SDP parser, and RTCP-SR parser for lip-sync)
 * - support for stream_filter in case of chained demux (MPEG-TS)
 */

#ifndef IPPROTO_DCCP
# define IPPROTO_DCCP 33 /* IANA */
#endif

#ifndef IPPROTO_UDPLITE
# define IPPROTO_UDPLITE 136 /* from IANA */
#endif


/*
 * Local prototypes
 */
static int Control (demux_t *, int i_query, va_list args);
static int extract_port (char **phost);

/**
 * Probes and initializes.
 */
static int Open (vlc_object_t *obj)
{
    demux_t *demux = (demux_t *)obj;
    int tp; /* transport protocol */

    if (!strcmp (demux->psz_access, "dccp"))
        tp = IPPROTO_DCCP;
    else
    if (!strcmp (demux->psz_access, "rtptcp"))
        tp = IPPROTO_TCP;
    else
    if (!strcmp (demux->psz_access, "rtp"))
        tp = IPPROTO_UDP;
    else
    if (!strcmp (demux->psz_access, "udplite"))
        tp = IPPROTO_UDPLITE;
    else
        return VLC_EGENERIC;

    char *tmp = strdup (demux->psz_location);
    if (tmp == NULL)
        return VLC_ENOMEM;

    char *shost;
    char *dhost = strchr (tmp, '@');
    if (dhost != NULL)
    {
        *(dhost++) = '\0';
        shost = tmp;
    }
    else
    {
        dhost = tmp;
        shost = NULL;
    }

    /* Parses the port numbers */
    int sport = 0, dport = 0;
    if (shost != NULL)
        sport = extract_port (&shost);
    if (dhost != NULL)
        dport = extract_port (&dhost);
    if (dport == 0)
        dport = 5004; /* avt-profile-1 port */

    int rtcp_dport = var_CreateGetInteger (obj, "rtcp-port");

    /* Try to connect */
    int fd = -1, rtcp_fd = -1;

    switch (tp)
    {
        case IPPROTO_UDP:
        case IPPROTO_UDPLITE:
            fd = net_OpenDgram (obj, dhost, dport, shost, sport, tp);
            if (fd == -1)
                break;
            if (rtcp_dport > 0) /* XXX: source port is unknown */
                rtcp_fd = net_OpenDgram (obj, dhost, rtcp_dport, shost, 0, tp);
            break;

         case IPPROTO_DCCP:
#ifndef SOCK_DCCP /* provisional API (FIXME) */
# ifdef __linux__
#  define SOCK_DCCP 6
# endif
#endif
#ifdef SOCK_DCCP
            var_Create (obj, "dccp-service", VLC_VAR_STRING);
            var_SetString (obj, "dccp-service", "RTPV"); /* FIXME: RTPA? */
            fd = net_Connect (obj, dhost, dport, SOCK_DCCP, tp);
#else
            msg_Err (obj, "DCCP support not included");
#endif
            break;

        case IPPROTO_TCP:
            fd = net_Connect (obj, dhost, dport, SOCK_STREAM, tp);
            break;
    }

    free (tmp);
    if (fd == -1) {
        if (rtcp_fd != -1)
            net_Close(rtcp_fd);
        return VLC_EGENERIC;
    }
    net_SetCSCov (fd, -1, 12);

    /* Initializes demux */
    demux_sys_t *p_sys = malloc (sizeof (*p_sys));
    if (p_sys == NULL)
    {
        net_Close (fd);
        if (rtcp_fd != -1)
            net_Close (rtcp_fd);
        return VLC_EGENERIC;
    }

    p_sys->chained_demux = NULL;
#ifdef HAVE_SRTP
    p_sys->srtp         = NULL;
#endif
    p_sys->fd           = fd;
    p_sys->rtcp_fd      = rtcp_fd;
    p_sys->max_src      = var_CreateGetInteger (obj, "rtp-max-src");
    p_sys->timeout      = var_CreateGetInteger (obj, "rtp-timeout")
                        * CLOCK_FREQ;
    p_sys->max_dropout  = var_CreateGetInteger (obj, "rtp-max-dropout");
    p_sys->max_misorder = var_CreateGetInteger (obj, "rtp-max-misorder");
    p_sys->thread_ready = false;
    p_sys->autodetect   = true;

    demux->pf_demux   = NULL;
    demux->pf_control = Control;
    demux->p_sys      = p_sys;

    p_sys->session = rtp_session_create (demux);
    if (p_sys->session == NULL)
        goto error;

#ifdef HAVE_SRTP
    char *key = var_CreateGetNonEmptyString (demux, "srtp-key");
    if (key)
    {
        vlc_gcrypt_init ();
        p_sys->srtp = srtp_create (SRTP_ENCR_AES_CM, SRTP_AUTH_HMAC_SHA1, 10,
                                   SRTP_PRF_AES_CM, SRTP_RCC_MODE1);
        if (p_sys->srtp == NULL)
        {
            free (key);
            goto error;
        }

        char *salt = var_CreateGetNonEmptyString (demux, "srtp-salt");
        int val = srtp_setkeystring (p_sys->srtp, key, salt ? salt : "");
        free (salt);
        free (key);
        if (val)
        {
            msg_Err (obj, "bad SRTP key/salt combination (%s)",
                     vlc_strerror_c(val));
            goto error;
        }
    }
#endif

    if (vlc_clone (&p_sys->thread,
                   (tp != IPPROTO_TCP) ? rtp_dgram_thread : rtp_stream_thread,
                   demux, VLC_THREAD_PRIORITY_INPUT))
        goto error;
    p_sys->thread_ready = true;
    return VLC_SUCCESS;

error:
    Close (obj);
    return VLC_EGENERIC;
}


/**
 * Releases resources
 */
static void Close (vlc_object_t *obj)
{
    demux_t *demux = (demux_t *)obj;
    demux_sys_t *p_sys = demux->p_sys;

    if (p_sys->thread_ready)
    {
        vlc_cancel (p_sys->thread);
        vlc_join (p_sys->thread, NULL);
    }

#ifdef HAVE_SRTP
    if (p_sys->srtp)
        srtp_destroy (p_sys->srtp);
#endif
    if (p_sys->session)
        rtp_session_destroy (demux, p_sys->session);
    if (p_sys->rtcp_fd != -1)
        net_Close (p_sys->rtcp_fd);
    net_Close (p_sys->fd);
    free (p_sys);
}


/**
 * Extracts port number from "[host]:port" or "host:port" strings,
 * and remove brackets from the host name.
 * @param phost pointer to the string upon entry,
 * pointer to the hostname upon return.
 * @return port number, 0 if missing.
 */
static int extract_port (char **phost)
{
    char *host = *phost, *port;

    if (host[0] == '[')
    {
        host = ++*phost; /* skip '[' */
        port = strchr (host, ']');
        if (port)
            *port++ = '\0'; /* skip ']' */
    }
    else
        port = strchr (host, ':');

    if (port == NULL)
        return 0;
    *port++ = '\0'; /* skip ':' */
    return atoi (port);
}


/**
 * Control callback
 */
static int Control (demux_t *demux, int query, va_list args)
{
    demux_sys_t *sys = demux->p_sys;

    switch (query)
    {
        case DEMUX_GET_PTS_DELAY:
        {
            int64_t *v = va_arg (args, int64_t *);
            *v = INT64_C(1000) * var_InheritInteger (demux, "network-caching");
            return VLC_SUCCESS;
        }

        case DEMUX_CAN_PAUSE:
        case DEMUX_CAN_SEEK:
        case DEMUX_CAN_CONTROL_PACE:
        {
            bool *v = va_arg( args, bool * );
            *v = false;
            return VLC_SUCCESS;
        }
    }

    if (sys->chained_demux != NULL)
        return vlc_demux_chained_ControlVa (sys->chained_demux, query, args);

    switch (query)
    {
        case DEMUX_GET_POSITION:
        {
            float *v = va_arg (args, float *);
            *v = 0.;
            return VLC_SUCCESS;
        }

        case DEMUX_GET_LENGTH:
        case DEMUX_GET_TIME:
        {
            int64_t *v = va_arg (args, int64_t *);
            *v = 0;
            return VLC_SUCCESS;
        }
    }

    return VLC_EGENERIC;
}


/*
 * Generic packet handlers
 */

void *codec_init (demux_t *demux, es_format_t *fmt)
{
    if (fmt->i_cat == AUDIO_ES)
        aout_FormatPrepare (&fmt->audio);
    return es_out_Add (demux->out, fmt);
}

void codec_destroy (demux_t *demux, void *data)
{
    if (data)
        es_out_Del (demux->out, (es_out_id_t *)data);
}

/* Send a packet to decoder */
void codec_decode (demux_t *demux, void *data, block_t *block)
{
    if (data)
    {
        block->i_dts = VLC_TICK_INVALID; /* RTP does not specify this */
        es_out_SetPCR(demux->out, block->i_pts);
        es_out_Send (demux->out, (es_out_id_t *)data, block);
    }
    else
        block_Release (block);
}

static void *stream_init (demux_t *demux, const char *name)
{
    demux_sys_t *p_sys = demux->p_sys;

    if (p_sys->chained_demux != NULL)
        return NULL;
    p_sys->chained_demux = vlc_demux_chained_New(VLC_OBJECT(demux), name,
                                                 demux->out);
    return p_sys->chained_demux;
}

static void stream_destroy (demux_t *demux, void *data)
{
    demux_sys_t *p_sys = demux->p_sys;

    if (data)
    {
        vlc_demux_chained_Delete(data);
        p_sys->chained_demux = NULL;
    }
}

static void stream_header (demux_t *demux, void *data, block_t *block)
{
    VLC_UNUSED(demux);
    VLC_UNUSED(data);
    if(block->p_buffer[1] & 0x80) /* TS M-bit == discontinuity (RFC 2250, 2.1) */
    {
        block->i_flags |= BLOCK_FLAG_DISCONTINUITY;
    }
}

/* Send a packet to a chained demuxer */
static void stream_decode (demux_t *demux, void *data, block_t *block)
{
    if (data)
        vlc_demux_chained_Send(data, block);
    else
        block_Release (block);
    (void)demux;
}

static void *demux_init (demux_t *demux)
{
    return stream_init (demux, demux->psz_demux);
}

/*
 * Static payload types handler
 */

/* PT=0
 * PCMU: G.711 µ-law (RFC3551)
 */
static void *pcmu_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_MULAW);
    fmt.audio.i_rate = 8000;
    fmt.audio.i_physical_channels = AOUT_CHAN_CENTER;
    return codec_init (demux, &fmt);
}

/* PT=3
 * GSM
 */
static void *gsm_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_GSM);
    fmt.audio.i_rate = 8000;
    fmt.audio.i_physical_channels = AOUT_CHAN_CENTER;
    return codec_init (demux, &fmt);
}

/* PT=8
 * PCMA: G.711 A-law (RFC3551)
 */
static void *pcma_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_ALAW);
    fmt.audio.i_rate = 8000;
    fmt.audio.i_physical_channels = AOUT_CHAN_CENTER;
    return codec_init (demux, &fmt);
}

/* PT=10,11
 * L16: 16-bits (network byte order) PCM
 */
static void *l16s_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_S16B);
    fmt.audio.i_rate = 44100;
    fmt.audio.i_physical_channels = AOUT_CHANS_STEREO;
    return codec_init (demux, &fmt);
}

static void *l16m_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_S16B);
    fmt.audio.i_rate = 44100;
    fmt.audio.i_physical_channels = AOUT_CHAN_CENTER;
    return codec_init (demux, &fmt);
}

/* PT=12
 * QCELP
 */
static void *qcelp_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_QCELP);
    fmt.audio.i_rate = 8000;
    fmt.audio.i_physical_channels = AOUT_CHAN_CENTER;
    return codec_init (demux, &fmt);
}

/* PT=14
 * MPA: MPEG Audio (RFC2250, §3.4)
 */
static void *mpa_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_MPGA);
    fmt.audio.i_physical_channels = AOUT_CHANS_STEREO;
    fmt.b_packetized = false;
    return codec_init (demux, &fmt);
}

static void mpa_decode (demux_t *demux, void *data, block_t *block)
{
    if (block->i_buffer < 4)
    {
        block_Release (block);
        return;
    }

    block->i_buffer -= 4; /* 32-bits RTP/MPA header */
    block->p_buffer += 4;

    codec_decode (demux, data, block);
}


/* PT=32
 * MPV: MPEG Video (RFC2250, §3.5)
 */
static void *mpv_init (demux_t *demux)
{
    es_format_t fmt;

    es_format_Init (&fmt, VIDEO_ES, VLC_CODEC_MPGV);
    fmt.b_packetized = false;
    return codec_init (demux, &fmt);
}

static void mpv_decode (demux_t *demux, void *data, block_t *block)
{
    if (block->i_buffer < 4)
    {
        block_Release (block);
        return;
    }

    block->i_buffer -= 4; /* 32-bits RTP/MPV header */
    block->p_buffer += 4;
#if 0
    if (block->p_buffer[-3] & 0x4)
    {
        /* MPEG2 Video extension header */
        /* TODO: shouldn't we skip this too ? */
    }
#endif
    codec_decode (demux, data, block);
}


/* PT=33
 * MP2: MPEG TS (RFC2250, §2)
 */
static void *ts_init (demux_t *demux)
{
    char const* name = demux->psz_demux;

    if (*name == '\0' || !strcasecmp(name, "any"))
        name = NULL;

    return stream_init (demux, name ? name : "ts");
}


/* Not using SDP, we need to guess the payload format used */
/* see http://www.iana.org/assignments/rtp-parameters */
void rtp_autodetect (demux_t *demux, rtp_session_t *session,
                     const block_t *block)
{
    uint8_t ptype = rtp_ptype (block);
    rtp_pt_t pt = {
        .init = NULL,
        .destroy = codec_destroy,
        .header = NULL,
        .decode = codec_decode,
        .frequency = 0,
        .number = ptype,
    };

    /* Remember to keep this in sync with modules/services_discovery/sap.c */
    switch (ptype)
    {
      case 0:
        msg_Dbg (demux, "detected G.711 mu-law");
        pt.init = pcmu_init;
        pt.frequency = 8000;
        break;

      case 3:
        msg_Dbg (demux, "detected GSM");
        pt.init = gsm_init;
        pt.frequency = 8000;
        break;

      case 8:
        msg_Dbg (demux, "detected G.711 A-law");
        pt.init = pcma_init;
        pt.frequency = 8000;
        break;

      case 10:
        msg_Dbg (demux, "detected stereo PCM");
        pt.init = l16s_init;
        pt.frequency = 44100;
        break;

      case 11:
        msg_Dbg (demux, "detected mono PCM");
        pt.init = l16m_init;
        pt.frequency = 44100;
        break;

      case 12:
        msg_Dbg (demux, "detected QCELP");
        pt.init = qcelp_init;
        pt.frequency = 8000;
        break;

      case 14:
        msg_Dbg (demux, "detected MPEG Audio");
        pt.init = mpa_init;
        pt.decode = mpa_decode;
        pt.frequency = 90000;
        break;

      case 32:
        msg_Dbg (demux, "detected MPEG Video");
        pt.init = mpv_init;
        pt.decode = mpv_decode;
        pt.frequency = 90000;
        break;

      case 33:
        msg_Dbg (demux, "detected MPEG2 TS");
        pt.init = ts_init;
        pt.destroy = stream_destroy;
        pt.header = stream_header;
        pt.decode = stream_decode;
        pt.frequency = 90000;
        break;

      default:
        /*
         * If the rtp payload type is unknown then check demux if it is specified
         */
        if (!strcmp(demux->psz_demux, "h264")
         || !strcmp(demux->psz_demux, "ts"))
        {
            msg_Dbg (demux, "dynamic payload format %s specified by demux",
                     demux->psz_demux);
            pt.init = demux_init;
            pt.destroy = stream_destroy;
            pt.decode = stream_decode;
            pt.frequency = 90000;
            break;
        }
        if (ptype >= 96)
        {
            char *dynamic = var_InheritString(demux, "rtp-dynamic-pt");
            if (dynamic == NULL)
                ;
            else if (!strcmp(dynamic, "theora"))
            {
                msg_Dbg (demux, "assuming Theora Encoded Video");
                pt.init = theora_init;
                pt.destroy = xiph_destroy;
                pt.decode = xiph_decode;
                pt.frequency = 90000;

                free (dynamic);
                break;
            }
            else
                msg_Err (demux, "unknown dynamic payload format `%s' "
                                "specified", dynamic);
            free (dynamic);
        }

        msg_Err (demux, "unspecified payload format (type %"PRIu8")", ptype);
        msg_Info (demux, "A valid SDP is needed to parse this RTP stream.");
        vlc_dialog_display_error (demux, N_("SDP required"),
             N_("A description in SDP format is required to receive the RTP "
                "stream. Note that rtp:// URIs cannot work with dynamic "
                "RTP payload format (%"PRIu8")."), ptype);
        return;
    }
    rtp_add_type (demux, session, &pt);
}

/*
 * Dynamic payload type handlers
 * Hmm, none implemented yet apart from Xiph ones.
 */