vlc/modules/access/udp.c

/*****************************************************************************
 * udp.c: raw UDP input module
 *****************************************************************************
 * Copyright (C) 2001-2005 VLC authors and VideoLAN
 * Copyright (C) 2007 Remi Denis-Courmont
 *
 * Authors: Christophe Massiot <massiot@via.ecp.fr>
 *          Tristan Leteurtre <tooney@via.ecp.fr>
 *          Laurent Aimar <fenrir@via.ecp.fr>
 *          Jean-Paul Saman <jpsaman #_at_# m2x dot nl>
 *          Remi Denis-Courmont
 *
 * Reviewed: 23 October 2003, Jean-Paul Saman <jpsaman _at_ videolan _dot_ org>
 *
 * This program 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 program 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 program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_access.h>
#include <vlc_network.h>
#include <vlc_block.h>
#include <vlc_interrupt.h>
#ifdef HAVE_POLL_H
# include <poll.h>
#endif
#ifdef HAVE_SYS_UIO_H
# include <sys/uio.h>
#endif

/* Buffer can be max theoretical datagram content minus anticipated MTU.
 * IPv6 headers are larger than IPv4, ignore IPv6 jumbograms.
 */
#define MRU 65507u

typedef struct {
    int fd;
    int timeout;

    size_t length;
    char *offset;
    char buf[MRU];
} access_sys_t;

static int Control(stream_t *access, int query, va_list args)
{
    switch (query) {
        case STREAM_CAN_SEEK:
        case STREAM_CAN_FASTSEEK:
        case STREAM_CAN_PAUSE:
        case STREAM_CAN_CONTROL_PACE:
            *va_arg(args, bool *) = false;
            break;

        case STREAM_GET_PTS_DELAY:
            *va_arg(args, vlc_tick_t *) =
                VLC_TICK_FROM_MS(var_InheritInteger(access, "network-caching"));
            break;

        default:
            return VLC_EGENERIC;
    }
    return VLC_SUCCESS;
}

static ssize_t Read(stream_t *access, void *buf, size_t len)
{
    access_sys_t *sys = access->p_sys;

    if (sys->length > 0) {
        if (len > sys->length)
            len = sys->length;

        memcpy(buf, sys->offset, len);
        sys->offset += len;
        sys->length -= len;
        return len;
    }

    struct pollfd ufd[1];

    ufd[0].fd = sys->fd;
    ufd[0].events = POLLIN;

    switch (vlc_poll_i11e(ufd, 1, sys->timeout)) {
        case 0:
            msg_Err(access, "receive time-out");
            return 0;
        case -1:
            return -1;
    }

    struct iovec iov[] = {
        { .iov_base = buf,      .iov_len = len, },
        { .iov_base = sys->buf, .iov_len = MRU, },
    };
    struct msghdr msg = {
        .msg_iov = iov,
        .msg_iovlen = ARRAY_SIZE(iov),
    };
    ssize_t val = recvmsg(sys->fd, &msg, 0);

    if (val <= 0) /* empty (0 bytes) payload does *not* mean EOF here */
        return -1;

    if (unlikely((size_t)val > len)) {
        sys->offset = sys->buf;
        sys->length = val - len;
        val = len;
    }

    return val;
}

/*****************************************************************************
 * Open: open the socket
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    stream_t     *p_access = (stream_t*)p_this;
    access_sys_t *sys;

    if( p_access->b_preparsing )
        return VLC_EGENERIC;

    sys = vlc_obj_malloc( p_this, sizeof( *sys ) );
    if( unlikely( sys == NULL ) )
        return VLC_ENOMEM;

    sys->length = 0;
    p_access->p_sys = sys;
    p_access->pf_read = Read;
    p_access->pf_block = NULL;
    p_access->pf_control = Control;
    p_access->pf_seek = NULL;

    char *psz_name = strdup( p_access->psz_location );
    char *psz_parser;
    const char *psz_server_addr, *psz_bind_addr = "";
    int  i_bind_port = 1234, i_server_port = 0;

    if( unlikely(psz_name == NULL) )
        return VLC_ENOMEM;

    /* Parse psz_name syntax :
     * [serveraddr[:serverport]][@[bindaddr]:[bindport]] */
    psz_parser = strchr( psz_name, '@' );
    if( psz_parser != NULL )
    {
        /* Found bind address and/or bind port */
        *psz_parser++ = '\0';
        psz_bind_addr = psz_parser;

        if( psz_bind_addr[0] == '[' )
            /* skips bracket'd IPv6 address */
            psz_parser = strchr( psz_parser, ']' );

        if( psz_parser != NULL )
        {
            psz_parser = strchr( psz_parser, ':' );
            if( psz_parser != NULL )
            {
                *psz_parser++ = '\0';
                i_bind_port = atoi( psz_parser );
            }
        }
    }

    psz_server_addr = psz_name;
    psz_parser = ( psz_server_addr[0] == '[' )
        ? strchr( psz_name, ']' ) /* skips bracket'd IPv6 address */
        : psz_name;

    if( psz_parser != NULL )
    {
        psz_parser = strchr( psz_parser, ':' );
        if( psz_parser != NULL )
        {
            *psz_parser++ = '\0';
            i_server_port = atoi( psz_parser );
        }
    }

    msg_Dbg( p_access, "opening server=%s:%d local=%s:%d",
             psz_server_addr, i_server_port, psz_bind_addr, i_bind_port );

    sys->fd = net_OpenDgram( p_access, psz_bind_addr, i_bind_port,
                             psz_server_addr, i_server_port, IPPROTO_UDP );
    free( psz_name );
    if( sys->fd == -1 )
    {
        msg_Err( p_access, "cannot open socket" );
        return VLC_EGENERIC;
    }

    sys->timeout = var_InheritInteger( p_access, "udp-timeout");
    if( sys->timeout > 0)
        sys->timeout *= 1000;

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close: free unused data structures
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    stream_t     *p_access = (stream_t*)p_this;
    access_sys_t *sys = p_access->p_sys;

    net_Close( sys->fd );
}

#define TIMEOUT_TEXT N_("UDP Source timeout (sec)")

vlc_module_begin()
    set_shortname(N_("UDP"))
    set_description(N_("UDP input"))
    set_subcategory(SUBCAT_INPUT_ACCESS)

    add_obsolete_integer("udp-buffer") /* since 3.0.0 */
    add_integer("udp-timeout", -1, TIMEOUT_TEXT, NULL)

    set_capability("access", 0)
    add_shortcut("udp", "udpstream", "udp4", "udp6")

    set_callbacks(Open, Close)
vlc_module_end()