[vlc-devel] [PATCH] Addressed items in original AMT code submission and added FQDN support

Wayne Brassem wbrassem at rogers.com
Fri Jan 18 20:49:47 CET 2019


Great comments.  Thank you.  I’ll get on it.  And next time I’ll try to squash all three files atm.c, amt.h and Makefile.am into a single patch since they need to be applied together.
Wayne.

> On Jan 18, 2019, at 12:34 PM, Tristan Matthews <tmatth at videolan.org> wrote:
> 
> Hi,
> 
> On Thu, Jan 17, 2019 at 6:41 AM Wayne Brassem <wbrassem at rogers.com <mailto:wbrassem at rogers.com>> wrote:
>> 
>> Addressing items raised in https://mailman.videolan.org/pipermail/vlc-devel/2018-November/121776.html and added FQDN support to the AMT code.
>> AMT stands for Automatic Multicast Tunnelling and allow the user to receive multicast streams over an non-multicast enabled network by tunnelling through an AMT relay.
>> 
>> From 91ef0bbc4b43eceaa3aea6cb2710232370a67ec8 Mon Sep 17 00:00:00 2001
>> From: Wayne Brassem <wbrassem at rogers.com>
>> Date: Mon, 14 Jan 2019 18:25:02 -0500
>> Subject: [PATCH 1/3] Addressed items in original AMT code submission and added
>> FQDN support
>> 
>> ---
>> modules/access/Makefile.am | 4 ++++
>> 1 file changed, 4 insertions(+)
>> 
>> diff --git a/modules/access/Makefile.am b/modules/access/Makefile.am
>> index c56cb8fe3a..792c6efb04 100644
>> --- a/modules/access/Makefile.am
>> +++ b/modules/access/Makefile.am
>> @@ -373,6 +373,10 @@ libudp_plugin_la_SOURCES = access/udp.c
>> libudp_plugin_la_LIBADD = $(SOCKET_LIBS)
>> access_LTLIBRARIES += libudp_plugin.la
>> 
>> +libamt_plugin_la_SOURCES = access/amt.c access/amt.h
>> +libamt_plugin_la_LIBADD = $(SOCKET_LIBS)
>> +access_LTLIBRARIES += libamt_plugin.la
>> +
>> libunc_plugin_la_SOURCES = access/unc.c access/smb_common.h
>> libunc_plugin_la_LIBADD = -lmpr -lnetapi32
>> if HAVE_WIN32
>> --
>> 2.17.2 (Apple Git-113)
>> 
>> From 91c757f47445095ac8de8574a8b216cca3043898 Mon Sep 17 00:00:00 2001
>> From: Wayne Brassem <wbrassem at rogers.com>
>> Date: Mon, 14 Jan 2019 18:47:06 -0500
>> Subject: [PATCH 2/3] Addressed concerns in first submissions and added support
>> for FQDN
>> 
>> ---
>> modules/access/amt.c | 1208 ++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 1208 insertions(+)
>> create mode 100644 modules/access/amt.c
>> 
>> diff --git a/modules/access/amt.c b/modules/access/amt.c
>> new file mode 100644
>> index 0000000000..df023be9dc
>> --- /dev/null
>> +++ b/modules/access/amt.c
>> @@ -0,0 +1,1208 @@
>> +/**
>> + * @file amt.c
>> + * @brief Automatic Multicast Tunneling Protocol (AMT) file for VLC media player
>> + * Allows multicast streaming when not in a multicast-enabled network
>> + * Currently IPv4 is supported, but IPv6 is not yet.
>> + *
>> + * Copyright (C) 2018 VLC authors and VideoLAN
>> + * Copyright (c) Juniper Networks, Inc., 2018. All rights reserved.
>> + *
>> + * Authors: Christophe Massiot <massiot at via.ecp.fr>         - original UDP code
>> + *          Tristan Leteurtre <tooney at via.ecp.fr>           - original UDP code
>> + *          Laurent Aimar <fenrir at via.ecp.fr>               - original UDP code
>> + *          Jean-Paul Saman <jpsaman #_at_# m2x dot nl>     - original UDP code
>> + *          Remi Denis-Courmont                             - original UDP code
>> + *          Natalie Landsberg natalie.landsberg97 at gmail.com - AMT support
>> + *          Wayne Brassem <wbrassem at rogers.com>             - Added FQDN support
>> + *
>> + * This code is licensed to you under the GNU Lesser General Public License
>> + * version 2.1 or later. You may not use this code except in compliance with
>> + * the GNU Lesser General Public License.
>> + * This code is not an official Juniper product.
>> + *
>> + * 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 <errno.h>
>> +#include <ctype.h>
>> +#ifdef HAVE_ARPA_INET_H
>> +# include <arpa/inet.h>
>> +#endif
>> +
>> +#ifdef HAVE_SYS_SELECT_H
>> +# include <sys/select.h>
>> +#endif
>> +
>> +#ifdef HAVE_SYS_SOCKET_H
>> +# include <sys/socket.h>
>> +#endif
>> +
>> +#include <vlc_common.h>
>> +#include <vlc_demux.h>
>> +#include <vlc_plugin.h>
>> +#include <vlc_access.h>
>> +#include <vlc_network.h>
>> +#include <vlc_block.h>
>> +#include <vlc_interrupt.h>
>> +#include <vlc_url.h>
>> +
>> +#include "amt.h"
>> +
>> +#ifdef HAVE_POLL
>> + #include <poll.h>
>> +#endif
>> +#ifdef HAVE_SYS_UIO_H
>> + #include <sys/uio.h>
>> +#endif
>> +
>> +#define BUFFER_TEXT N_("Receive buffer")
>> +#define BUFFER_LONGTEXT N_("AMT receive buffer size (bytes)" )
>> +#define TIMEOUT_TEXT N_("Native multicast timeout (sec)")
>> +#define AMT_TIMEOUT_TEXT N_("AMT timeout (sec)")
>> +#define AMT_RELAY_ADDRESS N_("AMT relay (IP address or FQDN)")
>> +#define AMT_RELAY_ADDR_LONG N_("AMT relay anycast address, or specify the relay you want by address or fully qualified domain name")
>> +#define AMT_DEFAULT_RELAY N_("amt-relay.m2icast.net")
>> +
>> +static int  Open (vlc_object_t *);
>> +static void Close (vlc_object_t *);
>> +
>> +/* memory leak and packet counters */
>> +static int mem_alloc, packet;
> 
> This information should be stored in the access_sys_t struct instead
> of static globals, or just deleted since it seems to be for debugging
> only.
> 
>> +
>> +vlc_module_begin ()
>> +    set_shortname( N_("AMT" ) )
>> +    set_description( N_("AMT input") )
>> +    set_category( CAT_INPUT )
>> +    set_subcategory( SUBCAT_INPUT_ACCESS )
>> +
>> +    add_integer( "amt-timeout", 5, AMT_TIMEOUT_TEXT, NULL, true )
>> +    add_integer( "amt-native-timeout", 3, TIMEOUT_TEXT, NULL, true )
>> +    add_string( "amt-relay", AMT_DEFAULT_RELAY, AMT_RELAY_ADDRESS, AMT_RELAY_ADDR_LONG, true )
>> +
>> +    set_capability( "access", 0 )
>> +    add_shortcut( "amt" )
>> +
>> +    set_callbacks( Open, Close )
>> +vlc_module_end ()
>> +
>> +/*****************************************************************************
>> + * Control:
>> + *****************************************************************************/
>> +static int Control( stream_t *p_access, int i_query, va_list args )
>> +{
>> +    bool    *pb_bool;
>> +
>> +/*    msg_Dbg( p_access, "Control: mem_alloc = %d", mem_alloc); */
> 
> This can be deleted.
> 
>> +
>> +    switch( i_query )
>> +    {
>> +        case STREAM_CAN_SEEK:
>> +        case STREAM_CAN_FASTSEEK:
>> +        case STREAM_CAN_PAUSE:
>> +        case STREAM_CAN_CONTROL_PACE:
>> +            pb_bool = va_arg( args, bool * );
>> +            *pb_bool = false;
>> +            break;
>> +
>> +        case STREAM_GET_PTS_DELAY:
>> +            *va_arg( args, vlc_tick_t * ) =
>> +                VLC_TICK_FROM_MS(var_InheritInteger( p_access, "network-caching" ));
>> +        break;
>> +
>> +        default:
>> +            return VLC_EGENERIC;
>> +    }
>> +    return VLC_SUCCESS;
>> +}
>> +
>> +/*****************************************************************************
>> + * BlockUDP:
>> + *****************************************************************************/
>> +static block_t *BlockUDP(stream_t *p_access, bool *restrict eof)
>> +{
>> +    access_sys_t *sys = p_access->p_sys;
>> +    ssize_t len;
>> +
>> +    block_t *pkt = block_Alloc(sys->mtu);
>> +    char *amtpkt = malloc( DEFAULT_MTU );
>> +
>> +    packet++;
>> +    mem_alloc++;   /* do not include *pkt in memory alloc count because it gets freed by caller */
>> +
>> +/*    msg_Dbg( p_access, "BlockUDP Enter: packet = %d, mem_alloc = %d, pkt = %016x, amtpkt = %016x", packet, mem_alloc, (int) pkt, (int) amtpkt); */
>> +
>> +    if (unlikely(pkt == NULL))
>> +    {   /* OOM - dequeue and discard one packet */
>> +        char dummy;
>> +        recv(sys->fd, &dummy, 1, 0);
>> +        return NULL;
>> +    }
>> +
>> +    if (unlikely(amtpkt == NULL))
>> +    goto error;
>> +
>> +    struct iovec iov = {
>> +        .iov_base = pkt->p_buffer,
>> +        .iov_len  = sys->mtu,
>> +    };
>> +    struct msghdr msg = {
>> +        .msg_iov = &iov,
>> +        .msg_iovlen = 1,
>> +#ifdef __linux__
>> +        .msg_flags = MSG_TRUNC,
>> +#endif
>> +    };
>> +
>> +    struct pollfd ufd[1];
>> +
>> +    if( sys->tryAMT )
>> +        ufd[0].fd = sys->sAMT;
>> +    else
>> +        ufd[0].fd = sys->fd;
>> +    ufd[0].events = POLLIN;
>> +
>> +    switch (vlc_poll_i11e(ufd, 1, sys->timeout))
>> +    {
>> +        case 0:
>> +            msg_Err(p_access, "native multicast receive time-out, packet = %d", packet);
>> +            net_Close( sys->fd );
>> +            if( !sys->tryAMT )
>> +            {
>> +                if( open_amt_tunnel( p_access ) == false )
> 
> You can just do if (!open_amt_tunnel( p_access ))
> 
>> +                    goto error;
>> +                break;
>> +            }
>> +            else
>> +            {
>> +                msg_Err(p_access, "AMT receive time-out");
>> +                *eof = true;
>> +            }
>> +            /* fall through */
>> +        case -1:
>> +/*            msg_Dbg(p_access, "Exiting vlc_poll switch, packet = %d", packet); */
>> +            goto error;
>> +    }
>> +
>> +    if( sys->tryAMT )
>> +    {
>> +        len = recv( sys->sAMT, amtpkt, DEFAULT_MTU, 0 );
>> +
>> +        if( len < 0 || amtpkt[0] != AMT_MULT_DATA )
>> +            goto error;
>> +
>> +        ssize_t shift = IP_HDR_LEN + UDP_HDR_LEN + AMT_HDR_LEN;
>> +
>> +        if( len < shift )
>> +        {
>> +            msg_Err(p_access, "%zd bytes packet truncated (MTU was %zu)",
>> +                len, sys->mtu);
>> +            pkt->i_flags |= BLOCK_FLAG_CORRUPTED;
>> +            sys->mtu = len;
>> +        } else {
>> +            len -= shift;
>> +        }
>> +
>> +        memcpy( pkt->p_buffer, &amtpkt[shift], len );
>> +    }
>> +    else
>> +        len = recvmsg(sys->fd, &msg, 0);
>> +
>> +#ifdef MSG_TRUNC
>> +    if (msg.msg_flags & MSG_TRUNC)
>> +    {
>> +        msg_Err(p_access, "%zd bytes packet truncated (MTU was %zu)",
>> +                len, sys->mtu);
>> +        pkt->i_flags |= BLOCK_FLAG_CORRUPTED;
>> +        sys->mtu = len;
>> +    }
>> +    else
>> +#endif
>> +        pkt->i_buffer = len;
>> +
>> +    free( amtpkt );
>> +    mem_alloc--;
>> +
>> +/*    msg_Dbg( p_access, "BlockUDP: Main Exit: mem_alloc = %d, packet = %d", mem_alloc, packet); */
> 
> This can be deleted.
> 
>> +
>> +    return pkt;
>> +
>> +error:
>> +    free( amtpkt );
>> +    mem_alloc--;
>> +
>> +/*    msg_Dbg( p_access, "BlockUDP: Error Exit: mem_alloc = %d, packet = %d", mem_alloc, packet); */
>> +
>> +    return NULL;
>> +}
>> +
>> +/*****************************************************************************
>> + * Open: open the socket
>> + *****************************************************************************/
>> +static int Open( vlc_object_t *p_this )
>> +{
>> +    stream_t            *p_access = (stream_t*) p_this;
>> +    access_sys_t        *sys = NULL;
>> +    struct addrinfo      hints, *serverinfo = NULL;
>> +    struct sockaddr_in  *server_addr;
>> +    char                *psz_name = NULL, *saveptr, ip_buffer[INET_ADDRSTRLEN];
>> +    int                  i_bind_port = 1234, i_server_port = 0, VLC_ret = VLC_SUCCESS, res;
>> +    vlc_url_t            url;
>> +
>> +    mem_alloc = 0; packet = 0;
>> +/*    msg_Dbg( p_access, "Open: Enter: mem_alloc = %d", mem_alloc);
> 
> This can be deleted.
> 
>> +
>> +    if( p_access->b_preparsing )
>> +    {
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    sys = vlc_obj_malloc( p_this, sizeof( *sys ) );
>> +    mem_alloc++;
>> +
>> +    if( unlikely( sys == NULL ) )
>> +    {
>> +        VLC_ret = VLC_ENOMEM;
>> +        goto cleanup;
>> +    }
>> +    else
>> +        memset( sys, 0, sizeof( *sys ));
>> +
>> +    p_access->p_sys = sys;
>> +
>> +    /* Set up p_access */
>> +    ACCESS_SET_CALLBACKS( NULL, BlockUDP, Control, NULL );
>> +
>> +    if( !p_access->psz_location )
>> +    {
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    psz_name = strdup( p_access->psz_location );
>> +    mem_alloc++;
>> +    if ( unlikely( psz_name == NULL ) )
>> +    {
>> +        VLC_ret = VLC_ENOMEM;
>> +        goto cleanup;
>> +    }
>> +
>> +    /* Parse psz_name syntax :
>> +     * [serveraddr[:serverport]][@[bindaddr]:[bindport]] */
>> +    if( vlc_UrlParse( &url, p_access->psz_url ) != 0 )
>> +    {
>> +        msg_Err( p_access, "Invalid URL" );
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +    mem_alloc++;
>> +
>> +    if( url.i_port > 0 )
>> +        i_bind_port = url.i_port;
>> +
>> +    msg_Dbg( p_access, "opening multicast: %s:%d local=%s:%d",
>> +             url.psz_host, i_server_port, url.psz_path, i_bind_port );
>> +
>> +    if( ( url.psz_host == NULL ) || ( strlen( url.psz_host ) == 0 ) )
>> +    {
>> +        msg_Err( p_access, "Please enter a group and/or source address." );
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    memset( &hints, 0, sizeof( hints ));
>> +    hints.ai_family = AF_INET;  /* Setting to AF_UNSPEC accepts both IPv4 and IPv6 */
>> +    hints.ai_socktype = SOCK_DGRAM;
>> +
>> +    /* retrieve list of multicast addresses matching the multicast group identifier */
>> +    res = vlc_getaddrinfo( url.psz_host, AMT_PORT, &hints, &serverinfo );
>> +    mem_alloc++;
>> +
>> +    if( res )
>> +    {
>> +        msg_Err( p_access, "Could not find multicast group %s, reason: %s", url.psz_host, gai_strerror(res) );
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    /* Convert binary socket address to string */
>> +    server_addr = (struct sockaddr_in *) serverinfo->ai_addr;
>> +    inet_ntop(AF_INET, &(server_addr->sin_addr), ip_buffer, INET_ADDRSTRLEN);
>> +
>> +    /* release the allocated memory */
>> +    freeaddrinfo(serverinfo);
>> +    serverinfo = NULL;
>> +    mem_alloc--;
>> +
>> +    msg_Dbg( p_access, "Setting multicast group address to %s", ip_buffer);
>> +
>> +    sys->mcastGroup = strdup( ip_buffer );
>> +    mem_alloc++;
>> +    if( unlikely( sys->mcastGroup == NULL ) )
>> +    {
>> +        VLC_ret = VLC_ENOMEM;
>> +        goto cleanup;
>> +    }
>> +
>> +    /* The following uses strtok_r() because strtok() is not thread safe */
>> +    sys->srcAddr = strdup( strtok_r( psz_name, "@", &saveptr ) );
> 
> You may want to do this in 2 steps to check that strok_r worked as expected.
> 
>> +    mem_alloc++;
>> +
>> +    if( unlikely( sys->srcAddr == NULL ) )
>> +    {
>> +        VLC_ret = VLC_ENOMEM;
>> +        goto cleanup;
>> +    }
>> +
>> +    /* if strings are equal then no multicast source has been specified */
>> +    if( strcmp( url.psz_host, sys->srcAddr ) == 0 )
>> + {
>> +        strcpy(sys->srcAddr, "0.0.0.0");
>> +        msg_Dbg( p_access, "No multicast source address specified, trying ASM...");
>> +    }
>> +
>> +    /* retrieve list of source addresses matching the multicast source identifier */
>> +    res = vlc_getaddrinfo( sys->srcAddr, AMT_PORT, &hints, &serverinfo );
>> +    mem_alloc++;
>> +
>> +    if( res )
>> +    {
>> +        msg_Err( p_access, "Could not find multicast source %s, reason: %s", sys->srcAddr, gai_strerror(res) );
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    /* Convert binary socket address to string */
>> +    server_addr = (struct sockaddr_in *) serverinfo->ai_addr;
>> +    inet_ntop(AF_INET, &(server_addr->sin_addr), ip_buffer, INET_ADDRSTRLEN);
>> +
>> +    msg_Dbg( p_access, "Setting multicast source address to %s", ip_buffer);
>> +
>> +    /* free the original source address buffer (IP or FQDN) and assign it just the IP address */
>> +    free(sys->srcAddr);
>> +    sys->srcAddr = strdup( ip_buffer );
>> +
>> +    if( unlikely( sys->srcAddr == NULL ) )
>> +    {
>> +        VLC_ret = VLC_ENOMEM;
>> +        goto cleanup;
>> +    }
>> +
>> +    if( strcmp( url.psz_host, sys->srcAddr ) == 0 )
>> +        strcpy(sys->srcAddr, "0.0.0.0");
>> +
>> +    sys->relayAddr = var_InheritString( p_access, "amt-relay" );
>> +
>> +    if( unlikely(sys->relayAddr == NULL ) )
>> +    {
>> +        msg_Err( p_access, "No relay anycast or unicast address specified." );
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    msg_Dbg( p_access, "Addresses: mcastGroup: %s srcAddr: %s relayAddr: %s", \
>> +             sys->mcastGroup, sys->srcAddr, sys->relayAddr);
>> +
>> +    sys->fd = net_OpenDgram( p_access, sys->mcastGroup, i_bind_port,
>> +                             sys->srcAddr, i_server_port, IPPROTO_UDP );
>> +    if( sys->fd == -1 )
>> +    {
>> +        msg_Err( p_access, "cannot open socket" );
>> +        VLC_ret = VLC_EGENERIC;
>> +        goto cleanup;
>> +    }
>> +
>> +    sys->mtu = 7 * 188;
>> +
>> +    sys->timeout = var_InheritInteger( p_access, "amt-native-timeout");
>> +    if( sys->timeout > 0)
>> +        sys->timeout *= 1000;
>> +
>> +    sys->amtTimeout = var_InheritInteger( p_access, "amt-timeout" );
>> +    if( sys->amtTimeout > 0)
>> +        sys->amtTimeout *= 1000;
>> +
>> +    sys->tryAMT = false;
>> +    sys->threadReady = false;
>> +
>> +cleanup: /* fall through */
>> +
>> +    /* release the allocated memory */
>> +    free( psz_name );
>> +    vlc_UrlClean( &url );
>> +    freeaddrinfo( serverinfo );
>> +
>> +    mem_alloc-=3;
>> +
>> +    /* if an error occurred free the memory */
>> +    if ( VLC_ret != VLC_SUCCESS )
>> +    {
>> +        free( sys->mcastGroup );
>> +        free( sys->srcAddr );
>> +        vlc_obj_free( p_this, sys );
>> +        mem_alloc -= 3;
>> +    }
>> +
>> +/*    msg_Dbg( p_access, "Open: Exit: mem_alloc = %d", mem_alloc); */
>> +
>> +    return VLC_ret;
>> +}
>> +
>> +/*****************************************************************************
>> + * Close: free unused data structures
>> + *****************************************************************************/
>> +static void Close( vlc_object_t *p_this )
>> +{
>> +    char         relay_ip[INET_ADDRSTRLEN];
>> +    stream_t     *p_access = (stream_t*)p_this;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    inet_ntop(AF_INET, &(sys->relayAddrDisco.sin_addr), relay_ip, INET_ADDRSTRLEN);
>> +
>> +    if( strcmp(sys->srcAddr, "0.0.0.0") == 0 )
>> +        amt_leaveASM_group( p_access );
>> +    else
>> +        amt_leaveSSM_group( p_access );
>> +    amt_send_mem_update( p_access, relay_ip, true );
>> +
>> +    if( sys->threadReady )
>> +    {
>> +        sys->threadReady = false;
>> +        vlc_cancel( sys->updateThread );
>> +        vlc_join( sys->updateThread, NULL );
>> +    }
>> +
>> +    free( sys->mcastGroup );
>> +    free( sys->srcAddr );
>> +    vlc_obj_free( p_this, sys );
>> +
>> +    mem_alloc -= 3;
>> +    if (mem_alloc)
>> +        msg_Err( p_access, "Closing AMT plugin, mem_alloc = %d", mem_alloc);
>> +    else
>> +        msg_Dbg( p_access, "Closing AMT plugin, mem_alloc = %d", mem_alloc);
>> +
>> +    net_Close( sys->fd );
>> +    net_Close( sys->sAMT );
>> +    net_Close( sys->sQuery );
>> +}
>> +
>> +
>> +bool open_amt_tunnel( stream_t *p_access )
>> +{
>> +    struct addrinfo hints, *serverinfo, *server;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    memset( &hints, 0, sizeof( hints ));
>> +    hints.ai_family = AF_INET;  /* Setting to AF_UNSPEC accepts both IPv4 and IPv6 */
>> +    hints.ai_socktype = SOCK_DGRAM;
>> +
>> +/*    msg_Dbg( p_access, "open_amt_tunnel: Enter: mem_alloc = %d", mem_alloc); */
>> +
>> +    msg_Dbg( p_access, "Attempting AMT to %s...", sys->relayAddr);
>> +    sys->tryAMT = true;
>> +
>> +    /* retrieve list of addresses matching the AMT relay */
>> +    int res = vlc_getaddrinfo( sys->relayAddr, AMT_PORT, &hints, &serverinfo );
>> +    mem_alloc++;
>> +
>> +    if( res )
>> +    {
>> +        msg_Err( p_access, "Could not find relay %s, reason: %s", sys->relayAddr, gai_strerror(res) );
>> +        goto error;
>> +    }
>> +
>> +    /* iterate through the list of sockets to find one the works */
>> +    for (server = serverinfo; server != NULL; server = server->ai_next)
>> +    {
>> +        struct sockaddr_in *server_addr = (struct sockaddr_in *) server->ai_addr;
>> +        char relay_ip[INET_ADDRSTRLEN];
>> +
>> +        inet_ntop(AF_INET, &(server_addr->sin_addr), relay_ip, INET_ADDRSTRLEN);
>> +
>> +        msg_Dbg( p_access, "Trying AMT Server: %s", relay_ip);
>> +
>> +        sys->relayAddrDisco.sin_addr = server_addr->sin_addr;
>> +
>> +        /* if can't open socket try any others in list */
>> +        if( amt_sockets_init( p_access ) != 0 )
>> +            msg_Err( p_access, "Error initializing socket to %s", relay_ip );
>> +
>> +        /* Otherwise negotiate with AMT relay and confirm you can pull a UDP packet  */
>> +        else
>> +        {
>> +            amt_send_relay_discovery_msg( p_access, relay_ip );
>> +            msg_Dbg( p_access, "Sent relay AMT discovery message to %s", relay_ip );
>> +
>> +            if( !amt_rcv_relay_adv( p_access ) )
>> +            {
>> +                msg_Err( p_access, "Error receiving AMT relay advertisement msg from %s, skipping", relay_ip );
>> +                goto error;
>> +            }
>> +            msg_Dbg( p_access, "Received AMT relay advertisement from %s", relay_ip );
>> +
>> +            amt_send_relay_request( p_access, relay_ip );
>> +            msg_Dbg( p_access, "Sent AMT relay request message to %s", relay_ip );
>> +
>> +            if( !amt_rcv_relay_mem_query( p_access ) )
>> +            {
>> +                msg_Err( p_access, "Could not receive AMT relay membership query from %s, reason: %s", relay_ip, vlc_strerror(errno));
>> +                goto error;
>> +            }
>> +            msg_Dbg( p_access, "Received AMT relay membership query from %s", relay_ip );
>> +
>> +            if( strcmp(sys->srcAddr, "") == 0 )
>> +            {
>> +                if( amt_joinASM_group( p_access ) != 0 )
>> +                {
>> +                    msg_Err( p_access, "Error joining ASM %s", vlc_strerror(errno) );
>> +                    goto error;
>> +                }
>> +                msg_Dbg( p_access, "Joined ASM group: %s", sys->mcastGroup );
>> +            }
>> +            else {
>> +                if( amt_joinSSM_group( p_access ) != 0 )
>> +                {
>> +                    msg_Err( p_access, "Error joining SSM %s", vlc_strerror(errno) );
>> +                    goto error;
>> +                }
>> +                msg_Dbg( p_access, "Joined SSM src: %s group: %s", sys->srcAddr, sys->mcastGroup );
>> +            }
>> +
>> +            bool eof=false;
>> +            block_t *pkt;
>> +
>> +            /* Confirm that you can pull a UDP packet from the socket */
>> +            if ( (pkt = BlockUDP( p_access, &eof )) == false )
> 
> A ! here would be sufficient, checking that a pointer == false is not
> really idiomatic.
> 
>> +                msg_Dbg( p_access, "Unable to receive UDP packet from AMT relay %s for multicast group %s, skipping...", relay_ip, sys->mcastGroup );
>> +            else
>> +            {
>> +                block_Release(pkt);  /* don't decrement mem_alloc since pkt not included in count */
>> +                msg_Dbg( p_access, "Got UDP packet from multicast group %s via AMT relay %s, continuing...", sys->mcastGroup, relay_ip );
>> +                break;   /* found an active server sending UDP packets, so exit loop */
>> +           }
>> +        }
>> +    }
>> +
>> +    /* if server is NULL then no AMT relay is responding */
>> +    if (server == NULL)
>> +    {
>> +        msg_Err( p_access, "No AMT servers responding" );
>> +        goto error;
>> +    }
>> +
>> +    sys->queryTime = vlc_tick_now() / CLOCK_FREQ;
>> +
>> +    /* release the allocated memory */
>> +    freeaddrinfo(serverinfo);
>> +    mem_alloc--;
>> +
>> +/*    msg_Dbg( p_access, "open_amt_tunnel: Exit: mem_alloc = %d", mem_alloc); */
> 
> This can be deleted.
> 
>> +
>> +    return true;
>> +
>> +error:
>> +    /* release the allocated memory */
>> +    freeaddrinfo(serverinfo);
>> +    mem_alloc--;
>> +
>> +/*    msg_Dbg( p_access, "open_amt_tunnel: Exit: mem_alloc = %d", mem_alloc); */
> 
> This can be deleted.
> 
>> +
>> +    sys->threadReady = false;
>> +    return false;
>> +}
>> +/**
>> + * Calculate checksum
>> + * */
>> +unsigned short getChecksum( unsigned short *buffer, int nLen )
>> +{
>> +    int nleft = nLen;
>> +    int sum = 0;
>> +    unsigned short *w = buffer;
>> +    unsigned short answer = 0;
>> +
>> +    while (nleft > 1)
>> +    {
>> +        sum += *w++;
>> +        nleft -= 2;
>> +    }
>> +    if (nleft == 1)
>> +    {
>> +        *(unsigned char*)(&answer) = *(unsigned char*)w;
>> +        sum += answer;
>> +    }
>> +    sum = (sum >> 16) + (sum & 0xffff);
>> +    answer = ~sum;
>> +    return (answer);
>> +}
>> +
>> +/**
>> + * Make IGMP Membership report
>> + * */
>> +void makeReport( amt_igmpv3_membership_report_t *mr )
>> +{
>> +    mr->type = AMT_IGMPV3_MEMBERSHIP_REPORT_TYPEID;
>> +    mr->resv = 0;
>> +    mr->checksum = 0;
>> +    mr->resv2 = 0;
>> +    mr->nGroupRecord = htons(1);
>> +}
>> +
>> +/**
>> + * Make IP header
>> + * */
>> +void makeIPHeader( amt_ip_alert_t *p_ipHead )
>> +{
>> +    p_ipHead->ver_ihl = 0x46;
>> +    p_ipHead->tos = 0xc0;
>> +    p_ipHead->tot_len = htons( IP_HDR_IGMP_LEN + IGMP_REPORT_LEN );
>> +    p_ipHead->id = 0x00;
>> +    p_ipHead->frag_off = 0x0000;
>> +    p_ipHead->ttl = 0x01;
>> +    p_ipHead->protocol = 0x02;
>> +    p_ipHead->check = 0;
>> +    p_ipHead->srcAddr = INADDR_ANY;
>> +    p_ipHead->options = 0x0000;
>> +}
>> +
>> +/** Create relay discovery socket, query socket, UDP socket and
>> + * fills in relay anycast address for discovery
>> + * return 0 if successful, -1 if not
>> + */
>> +int amt_sockets_init( stream_t *p_access )
>> +{
>> +    struct sockaddr_in rcvAddr;
>> +    access_sys_t *sys = p_access->p_sys;
>> +    memset( &rcvAddr, 0, sizeof(struct sockaddr_in) );
>> +    int enable = 0, res = 0;
>> +
>> +    /* Relay anycast address for discovery */
>> +    sys->relayAddrDisco.sin_family = AF_INET;
>> +    sys->relayAddrDisco.sin_port = htons( AMT_PORT );
>> +
>> +    /* create UDP socket */
>> +    sys->sAMT = vlc_socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP, true );
>> +    if( sys->sAMT == -1 )
>> +    {
>> +        msg_Err( p_access, "Failed to create UDP socket" );
>> +        goto error;
>> +    }
>> +
>> +    res = setsockopt(sys->sAMT, IPPROTO_IP, IP_PKTINFO, &enable, sizeof(enable));
>> +    if(res < 0)
>> +    {
>> +        msg_Err( p_access, "Couldn't set socket options for IPPROTO_IP, IP_PKTINFO\n %s", vlc_strerror(errno));
>> +        goto error;
>> +    }
>> +
>> +    res = setsockopt(sys->sAMT, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
>> +    if(res < 0)
>> +    {
>> +        msg_Err( p_access, "Couldn't make socket reusable");
>> +        goto error;
>> +    }
>> +
>> +    rcvAddr.sin_family      = AF_INET;
>> +    rcvAddr.sin_port        = htons( 0 );
>> +    rcvAddr.sin_addr.s_addr = INADDR_ANY;
>> +
>> +    if( bind(sys->sAMT, (struct sockaddr *)&rcvAddr, sizeof(rcvAddr) ) != 0 )
>> +    {
>> +        msg_Err( p_access, "Failed to bind UDP socket error: %s", vlc_strerror(errno) );
>> +        goto error;
>> +    }
>> +
>> +    sys->sQuery = vlc_socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP, true );
>> +    if( sys->sQuery == -1 )
>> +    {
>> +        msg_Err( p_access, "Failed to create query socket" );
>> +        goto error;
>> +    }
>> +
>> +    /* bind socket to local address */
>> +    sys->stLocalAddr.sin_family      = AF_INET;
>> +    sys->stLocalAddr.sin_port        = htons( 0 );
>> +    sys->stLocalAddr.sin_addr.s_addr = INADDR_ANY;
>> +
>> +    if( bind(sys->sQuery, (struct sockaddr *)&sys->stLocalAddr, sizeof(struct sockaddr) ) != 0 )
>> +    {
>> +        msg_Err( p_access, "Failed to bind query socket" );
>> +        goto error;
>> +    }
>> +
>> +    sys->stSvrAddr.sin_family        = AF_INET;
>> +    sys->stSvrAddr.sin_port          = htons( 9124 );
>> +    res = inet_pton( AF_INET, "127.0.0.1", &sys->stSvrAddr.sin_addr );
>> +    if( res == 0 )
>> +    {
>> +        msg_Err( p_access, "Could not convert loopback address" );
>> +        goto error;
>> +    }
>> +
>> +    return 0;
>> +
>> +error:
>> +    net_Close( sys->sAMT );
>> +    net_Close( sys->sQuery );
>> +    return -1;
>> +}
>> +
>> +/**
>> + * Send a relay discovery message, before 3-way handshake
>> + * */
>> +void amt_send_relay_discovery_msg( stream_t *p_access, char *relay_ip )
>> +{
>> +    char          chaSendBuffer[AMT_DISCO_MSG_LEN];
>> +    unsigned int  ulNonce;
>> +    int           nRet;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    /* initialize variables */
>> +    memset( chaSendBuffer, 0, sizeof(chaSendBuffer) );
>> +    ulNonce = 0;
>> +    nRet = 0;
>> +
>> +    /*
>> +     * create AMT discovery message format
>> +     * +---------------------------------------------------+
>> +     * | Msg Type(1Byte)| Reserved (3 byte)| nonce (4byte) |
>> +     * +---------------------------------------------------+
>> +     */
>> +
>> +    chaSendBuffer[0] = AMT_RELAY_DISCO;
>> +    chaSendBuffer[1] = 0;
>> +    chaSendBuffer[2] = 0;
>> +    chaSendBuffer[3] = 0;
>> +
>> +    /* create nonce and copy into send buffer */
>> +    srand( (unsigned int)time(NULL) );
>> +    ulNonce = htonl( rand() );
>> +    memcpy( (void*)&chaSendBuffer[4], (void*)&ulNonce, sizeof(ulNonce) );
>> +    sys->glob_ulNonce = ulNonce;
>> +
>> +    /* send it */
>> +    nRet = sendto( sys->sAMT, chaSendBuffer, sizeof(chaSendBuffer), 0,\
>> +            (struct sockaddr *)&sys->relayAddrDisco, sizeof(struct sockaddr) );
>> +
>> +    if( nRet < 0)
>> +        msg_Err( p_access, "Sendto failed to %s with error %d.", relay_ip, errno);
>> +}
>> +
>> +/**
>> + * Send relay request message, stage 2 of handshake
>> + * */
>> +void amt_send_relay_request( stream_t *p_access, char *relay_ip )
>> +{
>> +    char         chaSendBuffer[AMT_REQUEST_MSG_LEN];
>> +    uint32_t     ulNonce;
>> +    int          nRet;
>> +    int          nRetry;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    memset( chaSendBuffer, 0, sizeof(chaSendBuffer) );
>> +
>> +    ulNonce = 0;
>> +    nRet = 0;
>> +    nRetry = 0;
>> +
>> +    /*
>> +     * create AMT request message format
>> +     * +-----------------------------------------------------------------+
>> +     * | Msg Type(1Byte)| Reserved(1byte)|P flag(1byte)|Reserved (2 byte)|
>> +     * +-----------------------------------------------------------------+
>> +     * |             nonce (4byte)                                       |
>> +     * +-----------------------------------------------------------------+
>> +     *
>> +     * The P flag is set to indicate which group membership protocol the
>> +     * gateway wishes the relay to use in the Membership Query response:
>> +
>> +     * Value Meaning
>> +
>> +     *  0    The relay MUST respond with a Membership Query message that
>> +     *       contains an IPv4 packet carrying an IGMPv3 General Query
>> +     *       message.
>> +     *  1    The relay MUST respond with a Membership Query message that
>> +     *       contains an IPv6 packet carrying an MLDv2 General Query
>> +     *       message.
>> +     *
>> +     */
>> +
>> +    chaSendBuffer[0] = AMT_REQUEST;
>> +    chaSendBuffer[1] = 0;
>> +    chaSendBuffer[2] = 0;
>> +    chaSendBuffer[3] = 0;
>> +
>> +    ulNonce = sys->glob_ulNonce;
>> +    memcpy( (void*)&chaSendBuffer[4], (void*)&ulNonce, sizeof(uint32_t) );
>> +
>> +    nRet = send( sys->sAMT, chaSendBuffer, sizeof(chaSendBuffer), 0 );
>> +
>> +    if( nRet < 0 )
>> +        msg_Err(p_access, "Error sending relay request to %s error: %s", relay_ip, vlc_strerror(errno) );
>> +}
>> +
>> +/*
>> +* create AMT request message format
>> +* +----------------------------------------------------------------------------------+
>> +* | Msg Type(1 byte)| Reserved (1 byte)| MAC (6 byte)| nonce (4 byte) | IGMP packet  |
>> +* +----------------------------------------------------------------------------------+
>> +*/
>> +void amt_send_mem_update( stream_t *p_access, char *relay_ip, bool leave)
>> +{
>> +    int           sendBufSize = IP_HDR_IGMP_LEN + MAC_LEN + NONCE_LEN + AMT_HDR_LEN;
>> +    char          pSendBuffer[ sendBufSize + IGMP_REPORT_LEN ];
>> +    uint32_t      ulNonce = 0;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    memset( &pSendBuffer, 0, sizeof(pSendBuffer) );
>> +
>> +    pSendBuffer[0] = AMT_MEM_UPD;
>> +
>> +    /* copy relay MAC response */
>> +    memcpy( (void*)&pSendBuffer[2], (void*)sys->relay_mem_query_msg.uchaMAC, MAC_LEN );
>> +
>> +    /* copy nonce */
>> +    ulNonce = ntohl(sys->glob_ulNonce);
>> +    memcpy( (void*)&pSendBuffer[8], (void*)&ulNonce, NONCE_LEN );
>> +
>> +    /* make IP header for IGMP packet */
>> +    amt_ip_alert_t p_ipHead;
>> +    memset( &p_ipHead, 0, IP_HDR_IGMP_LEN );
>> +    makeIPHeader( &p_ipHead );
>> +
>> +    struct sockaddr_in temp;
>> +    inet_pton( AF_INET, MCAST_ALLHOSTS, &(temp.sin_addr) );
>> +    p_ipHead.destAddr = temp.sin_addr.s_addr;
>> +    p_ipHead.check = getChecksum( (unsigned short*)&p_ipHead, IP_HDR_IGMP_LEN );
>> +
>> +    amt_igmpv3_groupRecord_t groupRcd;
>> +    groupRcd.auxDatalen = 0;
>> +    inet_pton( AF_INET, sys->mcastGroup, &(temp.sin_addr) );
>> +    groupRcd.ssm = temp.sin_addr.s_addr;
>> +
>> +    if( strcmp(sys->srcAddr, "0.0.0.0") != 0 )
>> +    {
>> +        groupRcd.type = leave ? AMT_IGMP_BLOCK:AMT_IGMP_INCLUDE;
>> +        groupRcd.nSrc = htons(1);
>> +
>> +        inet_pton( AF_INET, sys->srcAddr, &(temp.sin_addr) );
>> +        groupRcd.srcIP[0] = temp.sin_addr.s_addr;
>> +
>> +    } else {
>> +        groupRcd.type = leave ? AMT_IGMP_INCLUDE_CHANGE:AMT_IGMP_EXCLUDE_CHANGE;
>> +        groupRcd.nSrc = htons(0);
>> +    }
>> +
>> +    /* make IGMP membership report */
>> +    amt_igmpv3_membership_report_t p_igmpMemRep;
>> +    makeReport( &p_igmpMemRep );
>> +
>> +    memcpy((void *)&p_igmpMemRep.grp[0], (void *)&groupRcd, (int)sizeof(groupRcd) );
>> +    p_igmpMemRep.checksum = getChecksum( (unsigned short*)&p_igmpMemRep, IGMP_REPORT_LEN );
>> +
>> +    amt_membership_update_msg_t memUpdateMsg;
>> +    memset((void*)&memUpdateMsg, 0, sizeof(memUpdateMsg));
>> +    memcpy((void*)&memUpdateMsg.ipHead, (void*)&p_ipHead, sizeof(p_ipHead) );
>> +    memcpy((void*)&memUpdateMsg.memReport, (void*)&p_igmpMemRep, sizeof(p_igmpMemRep) );
>> +
>> +    memcpy( (void*)&pSendBuffer[12], (void*)&memUpdateMsg, sizeof(memUpdateMsg) );
>> +
>> +    send( sys->sAMT, pSendBuffer, sizeof(pSendBuffer), 0 );
>> +
>> +    msg_Dbg( p_access, "AMT relay membership report sent to %s", relay_ip );
>> +}
>> +
>> +/**
>> + * Receive relay advertisement message
>> + *
>> + *
>> + *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> + *  |  V=0  |Type=2 |                   Reserved                    |
>> + *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> + *  |                        Discovery Nonce                        |
>> + *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> + *  |                                                               |
>> + *  ~                  Relay Address (IPv4 or IPv6)                 ~
>> + *  |                                                               |
>> + *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> + * */
>> +bool amt_rcv_relay_adv( stream_t *p_access )
>> +{
>> +    char pkt[RELAY_ADV_MSG_LEN];
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    memset( &pkt, 0, RELAY_ADV_MSG_LEN );
>> +
>> +    struct pollfd ufd[1];
>> +
>> +    ufd[0].fd = sys->sAMT;
>> +    ufd[0].events = POLLIN;
>> +
>> +    switch( vlc_poll_i11e(ufd, 1, sys->timeout) )
>> +    {
>> +        case 0:
>> +            msg_Err(p_access, "AMT relay advertisement receive time-out");
>> +            /* fall through */
>> +        case -1:
>> +            return false;
>> +    }
>> +
>> +    struct sockaddr temp;
>> +    uint32_t temp_size = sizeof( struct sockaddr );
>> +    ssize_t len = recvfrom( sys->sAMT, &pkt, RELAY_ADV_MSG_LEN, 0, &temp, &temp_size );
>> +
>> +    if (len < 0)
>> +    {
>> +        msg_Err(p_access, "Received message length less than zero");
>> +        return false;
>> +    }
>> +
>> +    memcpy( (void*)&sys->relay_adv_msg.type, &pkt[0], MSG_TYPE_LEN );
>> +    if( sys->relay_adv_msg.type != AMT_RELAY_ADV )
>> +    {
>> +        msg_Err( p_access, "Received message not an AMT relay advertisement, ignoring. ");
>> +        return false;
>> +    }
>> +
>> +    memcpy( (void*)&sys->relay_adv_msg.ulRcvNonce, &pkt[NONCE_LEN], NONCE_LEN );
>> +    if( sys->glob_ulNonce != sys->relay_adv_msg.ulRcvNonce )
>> +    {
>> +        msg_Err( p_access, "Discovery nonces differ! currNonce:%x rcvd%x", sys->glob_ulNonce, ntohl(sys->relay_adv_msg.ulRcvNonce) );
>> +        return false;
>> +    }
>> +
>> +    memcpy( (void*)&sys->relay_adv_msg.ipAddr, &pkt[8], 4 );
>> +
>> +    memset( &sys->relayAddress, 0, sizeof(sys->relayAddress) );
>> +    sys->relayAddress.sin_family       = AF_INET;
>> +    sys->relayAddress.sin_addr.s_addr  = sys->relay_adv_msg.ipAddr;
>> +    sys->relayAddress.sin_port         = htons( AMT_PORT );
>> +
>> +    int nRet = connect( sys->sAMT, (struct sockaddr *)&sys->relayAddress, sizeof(sys->relayAddress) );
>> +    if( nRet < 0 )
>> +    {
>> +        msg_Err( p_access, "Error connecting AMT UDP socket: %s", vlc_strerror(errno) );
>> +        return false;
>> +    }
>> +
>> +    return true;
>> +}
>> +
>> +/**
>> + * Receive relay membership query message
>> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> +   |  V=0  |Type=4 | Reserved  |L|G|         Response MAC          |
>> +   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
>> +   |                                                               |
>> +   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> +   |                         Request Nonce                         |
>> +   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> +   |                                                               |
>> +   |               Encapsulated General Query Message              |
>> +   ~                 IPv4:IGMPv3(Membership Query)                 ~
>> +   |                  IPv6:MLDv2(Listener Query)                   |
>> +   |                                                               |
>> +   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> +   |     Gateway Port Number       |                               |
>> +   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
>> +   |                                                               |
>> +   +                                                               +
>> +   |                Gateway IP Address (IPv4 or IPv6)              |
>> +   +                                                               +
>> +   |                                                               |
>> +   +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> +   |                               |
>> +   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> + */
>> +bool amt_rcv_relay_mem_query( stream_t *p_access )
>> +{
>> +    char pkt[RELAY_QUERY_MSG_LEN];
>> +    memset( &pkt, 0, RELAY_QUERY_MSG_LEN );
>> +    struct pollfd ufd[1];
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    ufd[0].fd = sys->sAMT;
>> +    ufd[0].events = POLLIN;
>> +
>> +    switch( vlc_poll_i11e(ufd, 1, sys->timeout) )
>> +    {
>> +        case 0:
>> +            msg_Err(p_access, "AMT relay membership query receive time-out");
>> +            /* fall through */
>> +        case -1:
>> +            return false;
>> +    }
>> +
>> +    ssize_t len = recv( sys->sAMT, &pkt, RELAY_QUERY_MSG_LEN, 0 );
>> +
>> +    if (len < 0)
>> +    {
>> +        msg_Err(p_access, "length less than zero");
>> +        return false;
>> +    }
>> +
>> +    memcpy( (void*)&sys->relay_mem_query_msg.type, &pkt[0], MSG_TYPE_LEN );
>> +    /* pkt[1] is reserved  */
>> +    memcpy( (void*)&sys->relay_mem_query_msg.uchaMAC[0], &pkt[AMT_HDR_LEN], MAC_LEN );
>> +    memcpy( (void*)&sys->relay_mem_query_msg.ulRcvedNonce, &pkt[AMT_HDR_LEN + MAC_LEN], NONCE_LEN );
>> +    if( sys->relay_mem_query_msg.ulRcvedNonce != sys->glob_ulNonce )
>> +    {
>> +        msg_Warn( p_access, "Nonces are different rcvd: %x glob: %x", sys->relay_mem_query_msg.ulRcvedNonce, sys->glob_ulNonce );
>> +        return false;
>> +    }
>> +
>> +    sys->glob_ulNonce = ntohl(sys->relay_mem_query_msg.ulRcvedNonce);
>> +
>> +    int shift = AMT_HDR_LEN + MAC_LEN + NONCE_LEN;
>> +    memcpy( (void*)&sys->relay_ip_hdr, (void*)&pkt[shift], IP_HDR_IGMP_LEN );
>> +
>> +    shift += IP_HDR_IGMP_LEN;
>> +    sys->relay_igmp_query.type = pkt[shift];
>> +    shift++;
>> +    sys->relay_igmp_query.max_resp_code = pkt[shift];
>> +    shift++;
>> +    memcpy( (void*)&sys->relay_igmp_query.checksum, &pkt[shift], 2 );
>> +    shift += 2;
>> +    memcpy( (void*)&sys->relay_igmp_query.ssmIP, &pkt[shift], 4 );
>> +    shift += 4;
>> +    sys->relay_igmp_query.s_qrv = pkt[shift];
>> +    shift++;
>> +    if( (int)pkt[shift] == 0 )
>> +        sys->relay_igmp_query.qqic = 125;
>> +    else if( (int)pkt[shift] < 128 )
>> +        sys->relay_igmp_query.qqic = pkt[shift];
>> +    else {
>> +        int qqic;
>> +        qqic = ((pkt[shift]&0x0f) + 0x10) << (((pkt[shift] >> 4)&0x07) + 3);
>> +        sys->relay_igmp_query.qqic = qqic;
>> +    }
>> +
>> +    shift++;
>> +    memcpy( (void*)&sys->relay_igmp_query.nSrc, &pkt[shift], 2 );
>> +    if( sys->relay_igmp_query.nSrc != 0 )
>> +    {
>> +        shift += 2;
>> +        memcpy( (void*)&sys->relay_igmp_query.srcIP, &pkt[shift], 4 );
>> +    }
>> +
>> +    /* if a membership thread exists cancel it */
>> +    if( sys->threadReady )
>> +    {
>> +        msg_Dbg( p_access, "Cancelling existing AMT relay membership update thread");
>> +
>> +        sys->threadReady = false;
>> +        vlc_cancel( sys->updateThread );
>> +        vlc_join( sys->updateThread, NULL );
>> +    }
>> +
>> +    msg_Dbg( p_access, "Spawning AMT relay membership update thread");
>> +
>> +    if( vlc_clone( &sys->updateThread, amt_mem_upd, p_access, VLC_THREAD_PRIORITY_LOW) )
>> +    {
>> +        msg_Err( p_access, "Could not create AMT relay membership update thread" );
>> +        return false;
>> +    }
>> +
>> +    /* set theadReady to true, thread will send periodic membership updates until false */
>> +    sys->threadReady = true;
>> +    return true;
>> +}
>> +
>> +/**
>> + * Join SSM group based on input addresses, or use the defaults
>> + * */
>> +int amt_joinSSM_group( stream_t *p_access )
>> +{
>> +    struct ip_mreq_source imr;
>> +    struct sockaddr_in temp;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    inet_pton( AF_INET, sys->mcastGroup, &(temp.sin_addr.s_addr) );
>> +    imr.imr_multiaddr.s_addr = temp.sin_addr.s_addr;
>> +
>> +    inet_pton( AF_INET, sys->srcAddr, &(temp.sin_addr.s_addr) );
>> +    imr.imr_sourceaddr.s_addr = temp.sin_addr.s_addr;
>> +    imr.imr_interface.s_addr = INADDR_ANY;
>> +
>> +    return setsockopt( sys->sAMT, IPPROTO_IP, IP_ADD_SOURCE_MEMBERSHIP, (char *)&imr, sizeof(imr) );
>> +}
>> +
>> +int amt_joinASM_group( stream_t *p_access )
>> +{
>> +    struct ip_mreq imr;
>> +    struct sockaddr_in temp;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    inet_pton( AF_INET, sys->mcastGroup, &(temp.sin_addr.s_addr) );
>> +    imr.imr_multiaddr.s_addr = temp.sin_addr.s_addr;
>> +    imr.imr_interface.s_addr = INADDR_ANY;
>> +
>> +    return setsockopt( sys->sAMT, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&imr, sizeof(imr) );
>> +}
>> +
>> +/**
>> + * Leave SSM group that was joined earlier.
>> + * */
>> +int amt_leaveSSM_group( stream_t *p_access )
>> +{
>> +    struct ip_mreq_source imr;
>> +    struct sockaddr_in temp;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    inet_pton( AF_INET, sys->mcastGroup, &(temp.sin_addr.s_addr) );
>> +    imr.imr_multiaddr.s_addr = temp.sin_addr.s_addr;
>> +
>> +    inet_pton( AF_INET, sys->srcAddr, &(temp.sin_addr.s_addr) );
>> +    imr.imr_sourceaddr.s_addr = temp.sin_addr.s_addr;
>> +    imr.imr_interface.s_addr = INADDR_ANY;
>> +
>> +    return setsockopt( sys->sAMT, IPPROTO_IP, IP_DROP_SOURCE_MEMBERSHIP, (char *)&imr, sizeof(imr) );
>> +}
>> +
>> +int amt_leaveASM_group( stream_t *p_access )
>> +{
>> +    struct ip_mreq imr;
>> +    struct sockaddr_in temp;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    inet_pton( AF_INET, sys->mcastGroup, &(temp.sin_addr.s_addr) );
>> +    imr.imr_multiaddr.s_addr = temp.sin_addr.s_addr;
>> +    imr.imr_interface.s_addr = INADDR_ANY;
>> +
>> +    return setsockopt( sys->sAMT, IPPROTO_IP, IP_DROP_MEMBERSHIP, (char *)&imr, sizeof(imr) );
>> +}
>> +
>> +void *amt_mem_upd( void *data )
>> +{
>> +    char          relay_ip[INET_ADDRSTRLEN];
>> +    stream_t     *p_access = (stream_t*) data;
>> +    access_sys_t *sys = p_access->p_sys;
>> +
>> +    msg_Dbg( p_access, "AMT relay membership update thread started" );
>> +
>> +    inet_ntop(AF_INET, &(sys->relayAddrDisco.sin_addr), relay_ip, INET_ADDRSTRLEN);
>> +
>> +    /* thread sends periodic AMT membership updates until Close() which clears sys->threadReady and terminates thread */
>> +    while ( sys->threadReady  )
>> +    {
>> +        amt_send_mem_update( p_access, relay_ip, false );
>> +        vlc_tick_sleep( (vlc_tick_t)sys->relay_igmp_query.qqic * CLOCK_FREQ );
>> +    }
>> +
>> +    return NULL;
>> +}
>> --
>> 2.17.2 (Apple Git-113)
>> 
>> From 72ea76afdb7679f11e19b0ac2cba6c81ec1aed33 Mon Sep 17 00:00:00 2001
>> From: Wayne Brassem <wbrassem at rogers.com>
>> Date: Mon, 14 Jan 2019 18:48:17 -0500
>> Subject: [PATCH 3/3] Modifed function declarations
>> 
>> ---
>> modules/access/amt.h | 220 +++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 220 insertions(+)
>> create mode 100644 modules/access/amt.h
>> 
>> diff --git a/modules/access/amt.h b/modules/access/amt.h
>> new file mode 100644
>> index 0000000000..7c14365cff
>> --- /dev/null
>> +++ b/modules/access/amt.h
>> @@ -0,0 +1,220 @@
>> +/*****************************************************************************
>> + * @file amt.h
>> + * @brief AMT access module structs
>> + *
>> + * Some of this code was pulled from or based off Cisco's open-source
>> + * SSMAMTtools repo.
>> + * Copyright (c) Juniper Networks, Inc., 2018 - 2018. All rights reserved.
>> + *
>> + * This code is licensed to you under the GNU Lesser General Public License
>> + * version 2.1 or later. You may not use this code except in compliance with
>> + * the GNU Lesser General Public License.
>> + * This code is not an official Juniper product.
>> + *
>> + * Authors: Natalie Landsberg <nlandsberg at juniper.net>
>> + *          Wayne Brassem <wbrassem at rogers.com>
>> + *
>> + * 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
>> + ****************************************************************************/
>> +
>> +/*****************************************************************************
>> + * Various Lengths of Msgs or Hdrs
>> + *****************************************************************************/
>> +#define MAC_LEN 6                /* length of generated MAC in bytes */
>> +#define NONCE_LEN 4              /* length of nonce in bytes */
>> +
>> +#define MSG_TYPE_LEN 1           /* length of msg type */
>> +#define RELAY_QUERY_MSG_LEN 48   /* total length of relay query */
>> +#define RELAY_ADV_MSG_LEN 12     /* length of relay advertisement message */
>> +#define IGMP_QUERY_LEN 24        /* length of encapsulated IGMP query message */
>> +#define IGMP_REPORT_LEN 20
>> +#define AMT_HDR_LEN 2            /* length of AMT header on a packet */
>> +#define IP_HDR_LEN 20            /* length of standard IP header */
>> +#define IP_HDR_IGMP_LEN 24       /* length of IP header with an IGMP report */
>> +#define UDP_HDR_LEN 8            /* length of standard UDP header */
>> +#define AMT_REQUEST_MSG_LEN 9
>> +#define AMT_DISCO_MSG_LEN 8
>> +
>> +/*****************************************************************************
>> + * Different AMT Message Types
>> + *****************************************************************************/
>> +#define AMT_RELAY_DISCO 1       /* relay discovery */
>> +#define AMT_RELAY_ADV 2         /* relay advertisement */
>> +#define AMT_REQUEST 3           /* request */
>> +#define AMT_MEM_QUERY 4         /* membership query */
>> +#define AMT_MEM_UPD 5           /* membership update */
>> +#define AMT_MULT_DATA 6         /* multicast data */
>> +#define AMT_TEARDOWN 7          /* teardown (not currently supported) */
>> +
>> +/*****************************************************************************
>> + * Different IGMP Message Types
>> + *****************************************************************************/
>> +#define AMT_IGMPV3_MEMBERSHIP_QUERY_TYPEID 0x11
>> +#define AMT_IGMPV3_MEMBERSHIP_REPORT_TYPEID 0x22
>> +/* IGMPv2, interoperability  */
>> +#define AMT_IGMPV1_MEMBERSHIP_REPORT_TYPEID 0x12
>> +#define AMT_IGMPV2_MEMBERSHIP_REPORT_TYPEID 0x16
>> +#define AMT_IGMPV2_MEMBERSHIP_LEAVE_TYPEID 0x17
>> +
>> +#define AMT_IGMP_INCLUDE 0x01
>> +#define AMT_IGMP_EXCLUDE 0x02
>> +#define AMT_IGMP_INCLUDE_CHANGE 0x03
>> +#define AMT_IGMP_EXCLUDE_CHANGE 0x04
>> +#define AMT_IGMP_ALLOW 0x05
>> +#define AMT_IGMP_BLOCK 0x06
>> +
>> +#define MCAST_ALLHOSTS "224.0.0.22"
>> +#define AMT_PORT 2268
>> +
>> +#define DEFAULT_MTU (1500u - (20 + 8))
>> +
>> +typedef struct access_sys_t access_sys_t;
>> +
>> +typedef struct _amt_ip {
>> +    uint8_t  ver_ihl;
>> +    uint8_t  tos;
>> +    uint16_t tot_len;
>> +    uint16_t id;
>> +    uint16_t frag_off;
>> +    uint8_t  ttl;
>> +    uint8_t  protocol;
>> +    uint16_t check;
>> +    uint32_t srcAddr;
>> +    uint32_t destAddr;
>> +} amt_ip_t;
>> +
>> +typedef struct _amt_ip_alert {
>> +    uint8_t  ver_ihl;
>> +    uint8_t   tos;
>> +    uint16_t tot_len;
>> +    uint16_t id;
>> +    uint16_t frag_off;
>> +    uint8_t  ttl;
>> +    uint8_t  protocol;
>> +    uint16_t check;
>> +    uint32_t srcAddr;
>> +    uint32_t destAddr;
>> +    uint32_t options;
>> +} amt_ip_alert_t;
>> +
>> +typedef struct _amt_igmpv3_groupRecord {
>> +    uint8_t type;
>> +    uint8_t auxDatalen;
>> +    uint16_t nSrc;
>> +    uint32_t ssm;
>> +    uint32_t srcIP[1];
>> +} amt_igmpv3_groupRecord_t;
>> +
>> +typedef struct _amt_igmpv3_membership_report {
>> +    uint8_t  type;
>> +    uint8_t  resv;
>> +    uint16_t checksum;
>> +    uint16_t resv2;
>> +    uint16_t nGroupRecord;
>> +    amt_igmpv3_groupRecord_t grp[1];
>> +} amt_igmpv3_membership_report_t;
>> +
>> +typedef struct _amt_igmpv3_membership_query {
>> +    uint8_t  type;
>> +    uint8_t  max_resp_code;  /* in 100ms, Max Resp Time = (mant | 0x10) << (exp + 3) */
>> +    uint32_t checksum;
>> +    uint32_t   ssmIP;
>> +    uint8_t  s_qrv;
>> +    uint8_t  qqic;           /* in second, query Time = (mant | 0x10) << (exp + 3) */
>> +    uint16_t nSrc;
>> +    uint32_t srcIP[1];
>> +} amt_igmpv3_membership_query_t;
>> +
>> +typedef struct _amt_membership_update_msg {
>> +    amt_ip_alert_t ipHead;
>> +    amt_igmpv3_membership_report_t memReport;
>> +} amt_membership_update_msg_t;
>> +
>> +typedef struct _amt_udpHdr {
>> +    uint16_t srcPort;
>> +    uint16_t dstPort;
>> +    uint16_t len;
>> +    uint16_t check;
>> +} amt_udpHdr_t;
>> +
>> +typedef struct _amt_multicast_data {
>> +    uint8_t   type;
>> +    uint8_t   resv;
>> +    amt_ip_t        ip;
>> +    amt_udpHdr_t    udp;
>> +    uint8_t   *buf;
>> +} amt_multicast_data_t;
>> +
>> +/* AMT Functions */
>> +int amt_sockets_init( stream_t *p_access );
>> +void amt_send_relay_discovery_msg( stream_t *p_access, char *relay_ip );
>> +void amt_send_relay_request( stream_t *p_access, char *relay_ip );
>> +int amt_joinSSM_group( stream_t *p_access );
>> +int amt_joinASM_group( stream_t *p_access );
>> +int amt_leaveASM_group( stream_t *p_access );
>> +int amt_leaveSSM_group( stream_t *p_access );
>> +bool amt_rcv_relay_adv( stream_t *p_access );
>> +bool amt_rcv_relay_mem_query( stream_t *p_access );
>> +void amt_send_mem_update( stream_t *p_access, char *relay_ip, bool leave );
>> +bool open_amt_tunnel( stream_t *p_access );
>> +void *amt_mem_upd( void *data );
>> +
>> +/* Utility functions */
>> +unsigned short getChecksum( unsigned short *buffer, int nLen );
>> +void makeReport( amt_igmpv3_membership_report_t *mr );
>> +void makeIPHeader( amt_ip_alert_t *p_ipHead );
> 
> These should be static and only in amt.c if they are not used outside
> of that file. Also we tend to use snake case rather than camel case.
> 
>> +
>> +struct access_sys_t
>> +{
>> +    int fd;
>> +    int sAMT;
>> +    int sQuery;
>> +    int timeout;
>> +    int amtTimeout;
>> +    size_t mtu;
>> +    bool tryAMT;
>> +    bool threadReady;
>> +
>> +    vlc_thread_t updateThread;
>> +    vlc_tick_t queryTime;
>> +
>> +    char *mcastGroup;
>> +    char *srcAddr;
>> +    char *relayAddr;
>> +
>> +    struct sockaddr_in relayAddrDisco;
>> +    struct sockaddr_in relayAddress;
>> +    struct sockaddr_in stLocalAddr;
>> +    struct sockaddr_in stSvrAddr;
>> +
>> +    uint32_t glob_ulNonce;
>> +    uint32_t ulRelayNonce;
>> +
>> +    struct relay_mem_query_msg_t {
>> +        uint8_t type;
>> +        uint32_t  ulRcvedNonce;
>> +        uint8_t uchaMAC[MAC_LEN];
>> +        uint8_t uchaIGMP[IGMP_QUERY_LEN];
>> +    } relay_mem_query_msg;
>> +
>> +    struct relay_adv_msg_t {
>> +        uint8_t type;
>> +        uint32_t ulRcvNonce;
>> +        uint32_t ipAddr;
>> +    } relay_adv_msg;
>> +
>> +    amt_ip_t relay_ip_hdr;
>> +    amt_igmpv3_membership_query_t relay_igmp_query;
>> +};
> 
> You may want to reorder this: http://www.catb.org/esr/structure-packing/ <http://www.catb.org/esr/structure-packing/>
> 
>> --
>> 2.17.2 (Apple Git-113)
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