[vlc-devel] [PATCH] AMT = Automatic Multicast Tunneling

Natalie Landsberg natalie.landsberg97 at gmail.com
Fri Aug 10 21:00:10 CEST 2018


This module aims to provide access to multicast streams from a
non-multicast enabled network. So, if you have a stream coming
from Internet2, you should be able to access it from outside of
Internet2 using this module. For example, some universities have
livestreams of ocean explorations that are on 24/7. Normally, you
would not be able to access these streams without being within the
university network. Now, for public ones, you can view them from
almost anywhere.

Essentially it creates a tunnel for you to have access to the stream.

It works similarly to udp native multicast streaming:
-provide server address
-provide multicast group address
-(optional) provide AMT relay address

There exists a relay which can be used to test the stream. Can be
provided upon request.

Modified code according to comments from VLC developers, listed below

-Reordered code to avoid forward declarations (but please verify again)
-Removed unnecessary code
-Made sure to use standard ISO C types
-Moved opening AMT tunnel to its own function outside of BlockUDP for cleaner read
-Changed timer to use vlc_tick_now
-Changed stack allocated array to dynamic in BlockUDP
-Changed URI parsers to use vlc_UrlParseFixup()
-Added private thread for update timer and fixed typo in Makefile.

Now supports both ASM and SSM. Fixed minor style issues and some error handling.

Changed instance of int, short, etc to uint*_t for wire format messages,
to guarantee a fixed-size. Tested and works on 64-bit MacOS, but needs
to be tested on 32-bit.

Can still change the fixed-size integers if needed.

Fixed what I think are all memory leaks. Needs verification. Added more error handling.
---
 modules/MODULES_LIST       |   1 +
 modules/access/Makefile.am |   4 +
 modules/access/amt.c       | 971 +++++++++++++++++++++++++++++++++++++
 modules/access/amt.h       | 219 +++++++++
 4 files changed, 1195 insertions(+)
 create mode 100644 modules/access/amt.c
 create mode 100644 modules/access/amt.h

diff --git a/modules/MODULES_LIST b/modules/MODULES_LIST
index e1978cc6e4..0e6a015384 100644
--- a/modules/MODULES_LIST
+++ b/modules/MODULES_LIST
@@ -33,6 +33,7 @@ $Id$
  * alphamask: Alpha layer mask video filter
  * alsa: audio output module using the ALSA API
  * amem: audio memory output
+ * amt: automatic multicast tunneling for multicast streaming
  * anaglyph: anaglyph 3d video filter
  * android_audiotrack: audio output for Android, based on AudioTrack
  * android_display: Android native window provider module
diff --git a/modules/access/Makefile.am b/modules/access/Makefile.am
index ee4290132f..ed8ad94a23 100644
--- a/modules/access/Makefile.am
+++ b/modules/access/Makefile.am
@@ -370,6 +370,10 @@ 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
diff --git a/modules/access/amt.c b/modules/access/amt.c
new file mode 100644
index 0000000000..3f9771de2a
--- /dev/null
+++ b/modules/access/amt.c
@@ -0,0 +1,971 @@
+/**
+ * @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
+ *
+ * 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 address")
+#define AMT_RELAY_ADDR_LONG N_("AMT relay anycast address, or specify the relay you want")
+
+static int  Open (vlc_object_t *);
+static void Close (vlc_object_t *);
+
+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_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;
+
+    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 *access, bool *restrict eof)
+{
+    access_sys_t *sys = access->p_sys;
+
+    block_t *pkt = block_Alloc(sys->mtu);
+    char *amtpkt = malloc( DEFAULT_MTU );
+
+    if (unlikely(pkt == NULL))
+    {   /* OOM - dequeue and discard one packet */
+        char dummy;
+        recv(sys->fd, &dummy, 1, 0);
+        return NULL;
+    }
+
+    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(access, "native multicast receive time-out");
+            net_Close( sys->fd );
+            if( !sys->tryAMT )
+            {
+                if( !open_amt_tunnel( sys, access ) )
+                    goto error;
+            }
+            else
+            {
+                msg_Err(access, "AMT receive time-out");
+                *eof = true;
+            }
+            /* fall through */
+        case -1:
+            goto error;
+    }
+
+    ssize_t len;
+    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(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 );
+        free( amtpkt );
+    }
+    else
+        len = recvmsg(sys->fd, &msg, 0);
+
+#ifdef MSG_TRUNC
+    if (msg.msg_flags & MSG_TRUNC)
+    {
+        msg_Err(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;
+
+    return pkt;
+
+error:
+    free( amtpkt );
+    block_Release(pkt);
+    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;
+
+    if( p_access->b_preparsing )
+        return VLC_EGENERIC;
+
+    sys = vlc_obj_malloc( p_this, sizeof( *sys ) );
+    if( unlikely( sys == NULL ) )
+    {
+        free( sys );
+        return VLC_ENOMEM;
+    }
+
+    p_access->p_sys = sys;
+
+    /* Set up p_access */
+    ACCESS_SET_CALLBACKS( NULL, BlockUDP, Control, NULL );
+
+    if( !p_access->psz_location )
+    {
+        free( sys );
+        return VLC_EGENERIC;
+    }
+
+    char *psz_name = strdup( p_access->psz_location );
+    int  i_bind_port = 1234, i_server_port = 0;
+
+    if( unlikely(psz_name == NULL) )
+        goto error;
+
+    /* Parse psz_name syntax :
+     * [serveraddr[:serverport]][@[bindaddr]:[bindport]] */
+    vlc_url_t url;
+
+    if( vlc_UrlParse( &url, p_access->psz_url ) != 0 )
+    {
+        msg_Err( p_access, "Invalid URL" );
+        vlc_UrlClean( &url );
+        goto error;
+    }
+
+    if( url.i_port > 0 )
+        i_bind_port = url.i_port;
+
+    msg_Dbg( p_access, "opening server=%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." );
+        goto error;
+    }
+    sys->mcastGroup = strdup( url.psz_host );
+    sys->srcAddr = strdup( strtok( psz_name, "@" ) );
+    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." );
+        goto error;
+    }
+
+    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" );
+        goto error;
+    }
+
+    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;
+
+    return VLC_SUCCESS;
+
+error:
+    free( psz_name );
+    vlc_obj_free( p_this, sys );
+    return VLC_EGENERIC;
+
+}
+
+/*****************************************************************************
+ * 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;
+
+    if( strcmp(sys->srcAddr, "0.0.0.0") == 0 )
+        amt_leaveASM_group( sys );
+    else
+        amt_leaveSSM_group( sys );
+    amt_send_mem_update( sys, true );
+
+    if( sys->threadReady )
+    {
+        sys->threadReady = false;
+        vlc_cancel( sys->updateThread );
+        vlc_join( sys->updateThread, NULL );
+    }
+
+    if( sys->mcastGroup != NULL )
+        free( sys->mcastGroup );
+
+    if( sys->srcAddr != NULL )
+        free( sys->srcAddr );
+
+    if( sys->relayAddr != NULL )
+        free( sys->relayAddr );
+
+    net_Close( sys->fd );
+    net_Close( sys->sAMT );
+    net_Close( sys->sQuery );
+}
+
+
+bool open_amt_tunnel( access_sys_t *sys, stream_t *access )
+{
+    msg_Dbg( access, "Attempting AMT...");
+    sys->tryAMT = true;
+
+    if( amt_sockets_init( sys, access ) != 0 )
+    {
+        msg_Err( access, "Error initializing sockets" );
+        goto error;
+    }
+
+    amt_send_relay_discovery_msg( sys, access );
+    msg_Dbg( access, "Sent AMT discovery message" );
+    if( !amt_rcv_relay_adv( sys, access ) )
+    {
+        msg_Err( access, "Error receiving relay adv msg, skipping" );
+        goto error;
+    }
+
+    msg_Dbg( access, "Received relay adv" );
+    amt_send_relay_request( sys, access );
+
+    if( !amt_rcv_relay_mem_query( sys, access ) )
+    {
+        msg_Err( access, "Could not receive relay membership query: %s", strerror(errno));
+        goto error;
+    }
+
+    msg_Dbg( access, "Received mem query" );
+    if( strcmp(sys->srcAddr, "") == 0 )
+    {
+        if( amt_joinASM_group( sys ) != 0 )
+        {
+            msg_Err( access, "Error joining SSM %s", strerror(errno) );
+            goto error;
+        }
+        msg_Dbg( access, "Joined ASM group: %s", sys->mcastGroup );
+    } else {
+        if( amt_joinSSM_group( sys ) != 0 )
+        {
+            msg_Err( access, "Error joining SSM %s", strerror(errno) );
+            goto error;
+        }
+        msg_Dbg( access, "Joined SSM src: %s group: %s", sys->srcAddr, sys->mcastGroup );
+    }
+
+    sys->queryTime = vlc_tick_now() / CLOCK_FREQ;
+
+    return true;
+error:
+    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 Membershipt 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( access_sys_t *sys, stream_t *p_access )
+{
+    struct sockaddr_in rcvAddr;
+    memset( &rcvAddr, 0, sizeof(struct sockaddr_in) );
+    int enable = 0;
+
+    /* Relay anycast address for discovery */
+    sys->relayAddrDisco.sin_family = AF_INET;
+    sys->relayAddrDisco.sin_port = htons( AMT_PORT );
+    int res = inet_pton( AF_INET, sys->relayAddr, &sys->relayAddrDisco.sin_addr );
+    if( res != 1 )
+    {
+        msg_Err( p_access, "Could not convert relay anycast" );
+        goto error;
+    }
+
+    /* 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", 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", 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( access_sys_t *sys, stream_t *p_access )
+{
+    char          chaSendBuffer[AMT_DISCO_MSG_LEN];
+    unsigned int  ulNonce;
+    int           nRet;
+
+    /* 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 with error %d.", errno);
+
+}
+
+/**
+ * Send relay request message, stage 2 of handshake
+ * */
+void amt_send_relay_request( access_sys_t *sys, stream_t *p_access )
+{
+    char chaSendBuffer[AMT_REQUEST_MSG_LEN];
+    uint32_t ulNonce;
+    int nRet;
+    int nRetry;
+
+    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 error: %s", 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( access_sys_t *sys, 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;
+    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 );
+}
+
+/**
+ * Receive relay advertisement message
+ *
+ *
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |  V=0  |Type=2 |                   Reserved                    |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                        Discovery Nonce                        |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                                                               |
+ *  ~                  Relay Address (IPv4 or IPv6)                 ~
+ *  |                                                               |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * */
+bool amt_rcv_relay_adv( access_sys_t *sys, stream_t *p_access )
+{
+    char pkt[RELAY_ADV_MSG_LEN];
+    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, "relay adv 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, "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 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", 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( access_sys_t *sys, stream_t *p_access )
+{
+    char pkt[RELAY_QUERY_MSG_LEN];
+    memset( &pkt, 0, RELAY_QUERY_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, "mem 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( vlc_clone( &sys->updateThread, amt_mem_upd, sys, VLC_THREAD_PRIORITY_LOW) )
+    {
+        msg_Err( p_access, "Could not create update thread" );
+        return false;
+    }
+
+    sys->threadReady = true;
+    return true;
+}
+
+/**
+ * Join SSM group based on input addresses, or use the defaults
+ * */
+int amt_joinSSM_group( access_sys_t *sys )
+{
+    struct ip_mreq_source imr;
+    struct sockaddr_in temp;
+    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( access_sys_t *sys )
+{
+    struct ip_mreq imr;
+    struct sockaddr_in temp;
+
+    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( access_sys_t *sys )
+{
+    struct ip_mreq_source imr;
+    struct sockaddr_in temp;
+    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( access_sys_t *sys )
+{
+    struct ip_mreq imr;
+    struct sockaddr_in temp;
+
+    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 )
+{
+    access_sys_t *sys = data;
+    for (;;)
+    {
+        if( !sys->threadReady )
+            break;
+        amt_send_mem_update( sys, false );
+        vlc_tick_sleep( (vlc_tick_t)sys->relay_igmp_query.qqic * CLOCK_FREQ );
+    }
+    return NULL;
+}
\ No newline at end of file
diff --git a/modules/access/amt.h b/modules/access/amt.h
new file mode 100644
index 0000000000..8c986ddf07
--- /dev/null
+++ b/modules/access/amt.h
@@ -0,0 +1,219 @@
+/*****************************************************************************
+ * @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>
+ *
+ * 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( access_sys_t *sys, stream_t *p_access );
+void amt_send_relay_discovery_msg( access_sys_t *sys, stream_t *p_access );
+void amt_send_relay_request( access_sys_t *sys, stream_t *p_access );
+int amt_joinSSM_group( access_sys_t *sys );
+int amt_joinASM_group( access_sys_t *sys );
+int amt_leaveASM_group( access_sys_t *sys );
+int amt_leaveSSM_group( access_sys_t *sys );
+bool amt_rcv_relay_adv( access_sys_t *sys, stream_t *p_access );
+bool amt_rcv_relay_mem_query( access_sys_t *sys, stream_t *p_access );
+void amt_send_mem_update( access_sys_t *sys, bool leave );
+bool open_amt_tunnel( access_sys_t *sys, stream_t *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 );
+
+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;
+};
\ No newline at end of file
-- 
2.17.1




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