[vlc-devel] [PATCH] Add support for AMT multicast tunneling over non-multicast enabled networks
Thomas Guillem
thomas at gllm.fr
Mon Jul 29 14:16:22 CEST 2019
Hello,
On Mon, Jul 22, 2019, at 19:46, Natalie Landsberg wrote:
> Updated based on VLC developer comments.
>
> Changes:
> 1. Made amt_send_mem_update() easier to read by using a shift variable,
> like amt_rcv_relay_mem_query()
> 2. p_ipHead changed to ipHead in amt_send_mem_update()
> 3. Instead of copying amt_membership_update_msg_t struct directly into
> buffer, copied
> one by one then asserted the buffer was not overflowing.
> 4. Fixed checks for len < 0 to include check for if message is not the
> actual message length to avoid
> reading uninitialized data.
> 5. Regarding read-buffer overflow from before. Re-read RFC, and the
> nSrc should always be 0 for a
> general IGMP query. If it is not 0, packet is dropped.
> 6. Fixed TRUE to true.
Thanks for the fixes.
> ---
> modules/access/Makefile.am | 4 +
> modules/access/amt.c | 1416 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 1420 insertions(+)
> create mode 100644 modules/access/amt.c
>
> diff --git a/modules/access/Makefile.am b/modules/access/Makefile.am
> index 919ac4b408..9b5202b5b6 100644
> --- a/modules/access/Makefile.am
> +++ b/modules/access/Makefile.am
> @@ -379,6 +379,10 @@ 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..059c3a133f
> --- /dev/null
> +++ b/modules/access/amt.c
> @@ -0,0 +1,1416 @@
> +/**
> + * @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>
> +#include <assert.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>
> +
> +#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")
> +
> +/*****************************************************************************
> + * 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_ANYCAST "0.0.0.0"
> +#define MCAST_ALLHOSTS "224.0.0.22"
> +#define LOCAL_LOOPBACK "127.0.0.1"
> +#define AMT_PORT 2268
> +
> +#define MAX_IPV4_UDP (65535u - (20 + 8))
> +
> +/* IPv4 Header Format */
> +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;
> +
> +/* IPv4 Header Format with options field */
> +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;
> +
> +/* IGMPv3 Group Record Format (RFC3376) */
> +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;
> +
> +/* IGMPv3 Membership Report Format (RFC3376) */
> +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;
> +
> +/* IGMPv3 Membership Query Format (RFC3376) */
> +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;
> +
> +/* ATM Membership Update Format (RFC7450) */
> +typedef struct _amt_membership_update_msg {
> + amt_ip_alert_t ipHead;
> + amt_igmpv3_membership_report_t memReport;
> +} amt_membership_update_msg_t;
> +
> +/* AMT Functions */
> +static int amt_sockets_init( stream_t *p_access );
> +static void amt_send_relay_discovery_msg( stream_t *p_access, char
> *relay_ip );
> +static void amt_send_relay_request( stream_t *p_access, char *relay_ip
> );
> +static int amt_joinSSM_group( stream_t *p_access );
> +static int amt_joinASM_group( stream_t *p_access );
> +static int amt_leaveASM_group( stream_t *p_access );
> +static int amt_leaveSSM_group( stream_t *p_access );
> +static bool amt_rcv_relay_adv( stream_t *p_access );
> +static bool amt_rcv_relay_mem_query( stream_t *p_access );
> +static void amt_send_mem_update( stream_t *p_access, char *relay_ip,
> bool leave );
> +static bool open_amt_tunnel( stream_t *p_access );
> +static void *amt_mem_upd( void *data );
> +
> +/* Struct to hold AMT state */
> +typedef struct _access_sys_t
> +{
> + char *mcastGroup;
> + char *mcastSrc;
> + char *relay;
> + char *relayDisco;
> + block_t *overflow_block;
> +
> + vlc_thread_t updateThread;
> + vlc_tick_t queryTime;
> +
> + /* Mulicast group and source */
> + struct sockaddr_in mcastGroupAddr;
> + struct sockaddr_in mcastSrcAddr;
> +
> + /* AMT relay imformation */
> + struct sockaddr_in relayDiscoAddr;
> + struct sockaddr_in relayAddr;
> + struct sockaddr_in stLocalAddr;
> + struct sockaddr_in stSvrAddr;
> +
> + /* AMT Relay Membership Query data (RFC7450) */
> + struct relay_mem_query_msg_t {
> + uint32_t ulRcvedNonce;
> + uint8_t type;
> + uint8_t uchaMAC[MAC_LEN];
> + uint8_t uchaIGMP[IGMP_QUERY_LEN];
> + } relay_mem_query_msg;
> +
> + /* AMT Relay Advertisement data (RFC7450) */
> + struct relay_adv_msg_t {
> + uint32_t ulRcvNonce;
> + uint32_t ipAddr;
> + uint8_t type;
> + } relay_adv_msg;
> +
> + amt_ip_t relay_ip_hdr;
> + amt_igmpv3_membership_query_t relay_igmp_query;
> + ssize_t mtu;
> +
> + uint32_t glob_ulNonce;
> + uint32_t ulRelayNonce;
> +
> + int fd;
> + int sAMT;
> + int sQuery;
> + int timeout;
> + int amtTimeout;
> +
> + bool tryAMT;
> + bool threadReady;
> +} access_sys_t;
> +
> +/* Standard open/close functions */
> +static int Open (vlc_object_t *);
> +static void Close (vlc_object_t *);
> +
> +/* Utility functions */
> +static unsigned short get_checksum( unsigned short *buffer, int nLen );
> +static void make_report( amt_igmpv3_membership_report_t *mr );
> +static void make_ip_header( amt_ip_alert_t *ipHead );
> +
> +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 ()
> +
> +/*****************************************************************************
> + * Local prototypes
> +
> *****************************************************************************/
> +static block_t *BlockUDP( stream_t *, bool * );
> +static int Control( stream_t *, int, va_list );
> +
> +/*****************************************************************************
> + * Open: Open a connection to the multicast feed
> +
> *****************************************************************************/
> +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, *psz_strtok_r,
> ip_buffer[INET_ADDRSTRLEN];
> + int i_bind_port = 1234, i_server_port = 0,
> VLC_ret = VLC_SUCCESS, res;
> + vlc_url_t url;
> +
> + if( p_access->b_preparsing )
> + return VLC_EGENERIC;
> +
> + /* Allocate the structure for holding AMT info and zeroize it */
> + sys = vlc_obj_calloc( p_this, 1, sizeof( *sys ) );
> + if( unlikely( sys == NULL ) )
> + return VLC_ENOMEM;
> +
> + /* The standard MPEG-2 transport is 188 bytes. 7 packets fit into
> a standard 1500 byte Ethernet frame */
> + sys->mtu = 7 * 188;
> +
> + /* Protective packet overflow buffer designed to accommodate
> maximum IPv4 UDP payload minus the anticapated MTU */
> + sys->overflow_block = block_Alloc(MAX_IPV4_UDP - sys->mtu);
> + if( unlikely( sys->overflow_block == NULL ) )
> + return VLC_ENOMEM;
> +
> + p_access->p_sys = sys;
> +
> + /* Set up p_access */
> + ACCESS_SET_CALLBACKS( NULL, BlockUDP, Control, NULL );
> +
> + if( !p_access->psz_location )
> + return VLC_EGENERIC;
> +
> + psz_name = strdup( p_access->psz_location );
> + if ( unlikely( psz_name == NULL ) )
> + return VLC_ENOMEM;
> +
> + /* Parse psz_name syntax :
> + * [serveraddr[:serverport]][@[bindaddr]:[bindport]] */
> + if( vlc_UrlParse( &url, p_access->psz_url ) != 0 )
> + {
> + msg_Err( p_access, "Invalid URL: %s", p_access->psz_url );
> + VLC_ret = VLC_EGENERIC;
> + goto cleanup;
> + }
> +
> + /* Determining the multicast source and group depends on the URL
> provided */
> + /*
> */
> + /* The address(es) in the URL can be in the form of IP address or
> FQDN */
> + /* By calling vlc_getaaddrinfo() you get it in IP form either way
> */
> + /*
> */
> + /* Case 1: amt://<source-ip-address>@<multicast-group-ip-address>
> */
> + /*
> */
> + /* sys->mcastSrc = <source-ip-address>
> */
> + /* sys->mcastSrcAddr = inet_pton( sys->mcastSrc )
> */
> + /*
> */
> + /* sys->mcastGroup = <multicast-group-ip-address>
> */
> + /* sys->mcastGroupAddr = inet_pton( sys->mcastGroup )
> */
> + /*
> */
> + /* Case 2: amt://<multicast-group-ip-address>
> */
> + /*
> */
> + /* sys->mcastSrc = MCAST_ANYCAST = "0.0.0.0"
> */
> + /* sys->mcastSrcAddr = inet_pton( sys->mcastSrc ) = 0
> */
> + /*
> */
> + /* sys->mcastGroup = <multicast-group-ip-address>
> */
> + /* sys->mcastGroupAddr = inet_pton( sys->mcastGroup )
> */
> + /*
> */
> +
> + /* If UDP port provided then assign port to stream */
> + 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 );
> +
> + /* Initialize hints prior to call to vlc_getaddrinfo with either
> IP address or FQDN */
> + 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
> );
> +
> + /* If an error returned print reason and exit */
> + 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);
> +
> + /* Store the binary socket representation of multicast group
> address */
> + sys->mcastGroupAddr = *server_addr;
> +
> + /* Release the allocated memory */
> + freeaddrinfo( serverinfo );
> + serverinfo = NULL;
> +
> + /* Store string representation */
> + sys->mcastGroup = strdup( ip_buffer );
> + if( unlikely( sys->mcastGroup == NULL ) )
> + {
> + VLC_ret = VLC_ENOMEM;
> + goto cleanup;
> + }
> +
> + msg_Dbg( p_access, "Setting multicast group address to %s",
> sys->mcastGroup);
> +
> + /* Extract the source from the URL, or the multicast group when no
> source is provided */
> + if ( !( psz_strtok_r = strtok_r( psz_name, "@", &saveptr ) ) )
> + {
> + msg_Err( p_access, "Could not parse location %s", psz_name);
> + VLC_ret = VLC_EGENERIC;
> + goto cleanup;
> + }
> +
> + /* Store the string representation */
> + sys->mcastSrc = strdup( psz_strtok_r );
> + if( unlikely( sys->mcastSrc == NULL ) )
> + {
> + VLC_ret = VLC_ENOMEM;
> + goto cleanup;
> + }
> +
> + /* If strings are equal then no multicast source has been
> specified, so try anycast */
> + if( strcmp( url.psz_host, sys->mcastSrc ) == 0 )
> + {
> + free( sys->mcastSrc );
> + sys->mcastSrc = strdup(MCAST_ANYCAST);
> + sys->mcastSrcAddr.sin_addr.s_addr = 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->mcastSrc, AMT_PORT, &hints,
> &serverinfo );
> +
> + /* If an error returned print reason and exit */
> + if( res )
> + {
> + msg_Err( p_access, "Could not find multicast source %s,
> reason: %s", sys->mcastSrc, 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);
> +
> + /* Store the binary socket representation of multicast source
> address */
> + sys->mcastSrcAddr = *server_addr;
> +
> + /* free the original source address buffer (IP or FQDN) and assign
> it just the IP address */
> + free( sys->mcastSrc );
> +
> + /* Store string representation */
> + sys->mcastSrc = strdup( ip_buffer );
> + if( unlikely( sys->mcastSrc == NULL ) )
> + {
> + VLC_ret = VLC_ENOMEM;
> + goto cleanup;
> + }
> +
> + msg_Dbg( p_access, "Setting multicast source address to %s",
> sys->mcastSrc);
> +
> + /* Pull the AMT relay address from the settings */
> + sys->relay = var_InheritString( p_access, "amt-relay" );
> + if( unlikely( sys->relay == 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 mcastSrc: %s relay:
> %s", \
> + sys->mcastGroup, sys->mcastSrc, sys->relay);
> +
> + /* Native multicast file descriptor */
> + sys->fd = net_OpenDgram( p_access, sys->mcastGroup, i_bind_port,
> + sys->mcastSrc, i_server_port, IPPROTO_UDP
> );
> + if( sys->fd == -1 )
> + {
> + msg_Err( p_access, "cannot open socket" );
> + VLC_ret = VLC_EGENERIC;
> + goto cleanup;
> + }
> +
> + 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 );
> +
> + /* if an error occurred free the memory */
> + if ( VLC_ret != VLC_SUCCESS )
> + {
> + msg_Dbg( p_access, "Open(): Before free( sys-> sys->Addr ) #4"
> );
> + free( sys->mcastGroup );
> + free( sys->mcastSrc );
> + }
> +
> + return VLC_ret;
> +}
> +
> +/*****************************************************************************
> + * Close: Cancel thread and free 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;
> +
> + msg_Dbg( p_access, "Closing AMT plugin" );
> +
> + /* If using AMT tunneling send leave message and free the relay
> addresses */
> + if ( sys->tryAMT )
> + {
> + /* Prepare socket options */
> + if( sys->mcastSrcAddr.sin_addr.s_addr )
> + amt_leaveSSM_group( p_access );
> + else
> + amt_leaveASM_group( p_access );
> +
> + /* Send IGMP leave message */
> + amt_send_mem_update( p_access, sys->relayDisco, true );
> +
> + free( sys->relay );
> + free( sys->relayDisco );
> + }
> +
> + /* If overflow block allocated then free the memory */
> + if( sys->overflow_block )
> + block_Release( sys->overflow_block );
> +
> + /* If membership thread spawned cancel it */
> + if( sys->threadReady )
> + {
> + msg_Dbg( p_access, "Canceling IGMP membership thread" );
> + sys->threadReady = false;
> + vlc_cancel( sys->updateThread );
> + vlc_join( sys->updateThread, NULL );
> + }
> +
> + free( sys->mcastGroup );
> + free( sys->mcastSrc );
> +
> + net_Close( sys->fd );
> + net_Close( sys->sAMT );
> + net_Close( sys->sQuery );
> +
> + msg_Dbg( p_access, "Exiting AMT plugin" );
> +}
> +
> +/*****************************************************************************
> + * Control: Define stream controls
> +
> *****************************************************************************/
> +static int Control( stream_t *p_access, int i_query, va_list args )
> +{
> + switch( i_query )
> + {
> + case STREAM_CAN_SEEK:
> + case STREAM_CAN_FASTSEEK:
> + case STREAM_CAN_PAUSE:
> + case STREAM_CAN_CONTROL_PACE:
> + *va_arg( args, bool * ) = false;
> + break;
> +
> + case STREAM_GET_PTS_DELAY:
> + *va_arg( args, vlc_tick_t * ) =
> + VLC_TICK_FROM_MS(var_InheritInteger( p_access,
> "network-caching" ));
> + break;
> +
> + default:
> + return VLC_EGENERIC;
> + }
> +
> + return VLC_SUCCESS;
> +}
> +
> +/*****************************************************************************
> + * BlockUDP: Responsible for returning the multicast payload
> + * BlockUDP: Sections of code are based upon BlockUDP code in udp.c
> + *
> + * Default MTU based on number of MPEG-2 transports carried in a 1500
> byte Ethernet frame
> + * however the code is able to receive maximal IPv4 UDP frames and
> then adjusts the MTU
> +
> *****************************************************************************/
> +static block_t *BlockUDP(stream_t *p_access, bool *restrict eof)
> +{
> + access_sys_t *sys = p_access->p_sys;
> + ssize_t len = 0, shift = 0, tunnel = IP_HDR_LEN + UDP_HDR_LEN +
> AMT_HDR_LEN;
> +
> + /* Allocate anticipated MTU buffer for holding the UDP packet
> suitable for native or AMT tunneled multicast */
> + block_t *pkt = block_Alloc( sys->mtu + tunnel );
> + if ( unlikely( pkt == NULL ) )
> + return NULL;
> +
> + /* Structure initialized to hold anticipated MTU buffer along with
> protective overflow buffer */
> + struct iovec iov[] = {{
> + .iov_base = pkt->p_buffer,
> + .iov_len = sys->mtu + tunnel,
> + },{
> + .iov_base = sys->overflow_block->p_buffer,
> + .iov_len = sys->overflow_block->i_buffer,
> + }};
> +
> + /* References the two element array above to be passed into
> recvmsg */
> + struct msghdr msg = {
> + .msg_iov = iov,
> + .msg_iovlen = 2,
> + };
> +
> + struct pollfd ufd[1];
> +
> + if( sys->tryAMT )
> + ufd[0].fd = sys->sAMT; /* AMT tunneling file descriptor */
> + else
> + ufd[0].fd = sys->fd; /* Native multicast file descriptor */
> + ufd[0].events = POLLIN;
> +
> + switch (vlc_poll_i11e(ufd, 1, sys->timeout))
> + {
> + case 0:
> + if( !sys->tryAMT )
> + {
> + msg_Err(p_access, "Native multicast receive time-out");
> + if( !open_amt_tunnel( p_access ) )
> + goto error;
> + break;
> + }
> + else
> + {
> + *eof = true;
> + }
> + /* fall through */
> + case -1:
> + goto error;
> + }
> +
> + /* If using AMT tunneling perform basic checks and point to
> beginning of the payload */
> + if( sys->tryAMT )
> + {
> + len = recvmsg( sys->sAMT, &msg, 0 );
> +
> + /* Check for the integrity of the received AMT packet */
> + if( len < 0 || *(pkt->p_buffer) != AMT_MULT_DATA )
> + goto error;
> +
> + /* Set the offet to the first byte of the payload */
> + shift += tunnel;
> +
> + /* If the length received is less than the AMT tunnel header
> then it's truncated */
> + if( len < tunnel )
> + {
> + msg_Err(p_access, "%zd bytes packet truncated (MTU was
> %zd)", len, sys->mtu);
> + pkt->i_flags |= BLOCK_FLAG_CORRUPTED;
> + }
> +
> + /* Otherwise subtract the length of the AMT encapsulation from
> the packet received */
> + else
> + {
> + len -= tunnel;
> + }
> + }
> +
> + /* Otherwise pull native multicast */
> + else
> + {
> + len = recvmsg(sys->fd, &msg, 0);
> + }
> +
> + /* If the payload length is greater than the MTU then the overflow
> buffer was utilized */
> + if ( unlikely( len > sys->mtu ) )
> + {
> + msg_Warn(p_access, "%zd bytes packet received (MTU was %zd),
> adjusting mtu", len, sys->mtu);
> +
> + block_t *gather_block = sys->overflow_block;
> +
> + /* Allocate a new overflow buffer based on the received
> payload length */
> + sys->overflow_block = block_Alloc(MAX_IPV4_UDP - len);
> +
> + /* Set number of bytes consumed in the overflow block */
> + gather_block->i_buffer = len - sys->mtu;
> +
> + /* Chain the anticipated packet and overflow buffers, copy
> into a single buffer and free the chain */
> + pkt->p_next = gather_block;
> + pkt = block_ChainGather( pkt );
> +
> + /* Adjust the anticipated MTU to match the payload received */
> + sys->mtu = len;
> + }
> +
> + /* Set the offset to payload start */
> + pkt->p_buffer += shift;
> + pkt->i_buffer -= shift;
> +
> + return pkt;
> +
> +error:
> + block_Release( pkt );
> + return NULL;
> +}
> +
> +/*****************************************************************************
> + * open_amt_tunnel: Create an AMT tunnel to the AMT relay
> +
> *****************************************************************************/
> +static 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, "Attempting AMT to %s...", sys->relay);
> + sys->tryAMT = true;
> +
> + /* Retrieve list of addresses matching the AMT relay */
> + int res = vlc_getaddrinfo( sys->relay, AMT_PORT, &hints,
> &serverinfo );
> +
> + /* If an error returned print reason and exit */
> + if( res )
> + {
> + msg_Err( p_access, "Could not find relay %s, reason: %s",
> sys->relay, gai_strerror(res) );
> + goto error;
> + }
> +
> + /* Iterate through the list of sockets to find one that 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];
> +
> + /* Convert to binary representation */
> + inet_ntop(AF_INET, &(server_addr->sin_addr), relay_ip,
> INET_ADDRSTRLEN);
> +
> + /* Store string representation */
> + sys->relayDisco = strdup( relay_ip );
> + if( unlikely( sys->relayDisco == NULL ) )
> + {
> + goto error;
> + }
> +
> + msg_Dbg( p_access, "Trying AMT Server: %s", sys->relayDisco);
> +
> + /* Store the binary representation */
> + sys->relayDiscoAddr.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 single source multicast send SSM join */
> + if( sys->mcastSrcAddr.sin_addr.s_addr )
> + {
> + 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->mcastSrc, sys->mcastGroup );
> + }
> +
> + /* If any source multicast send ASM join */
> + else {
> + 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 );
> + }
> +
> + bool eof=false;
> + block_t *pkt;
> +
> + /* Confirm that you can pull a UDP packet from the socket
> */
> + if ( !(pkt = BlockUDP( p_access, &eof )) )
> + msg_Err( p_access, "Unable to receive UDP packet from
> AMT relay %s for multicast group %s", relay_ip, sys->mcastGroup );
> + else
> + {
> + block_Release( pkt );
> + 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 );
> + return true;
> +
> +error:
> + /* release the allocated memory */
> + freeaddrinfo( serverinfo );
> + sys->threadReady = false;
> + return false;
> +}
> +
> +/**
> + * Calculate checksum
> + * */
> +static unsigned short get_checksum( 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
> + * */
> +static void make_report( 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
> + * */
> +static void make_ip_header( 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
> + */
> +static 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->relayDiscoAddr.sin_family = AF_INET;
> + sys->relayDiscoAddr.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, LOCAL_LOOPBACK, &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
> + * */
> +static 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( &chaSendBuffer[4], &ulNonce, sizeof(ulNonce) );
> + sys->glob_ulNonce = ulNonce;
> +
> + /* send it */
> + nRet = sendto( sys->sAMT, chaSendBuffer, sizeof(chaSendBuffer), 0,\
> + (struct sockaddr *)&sys->relayDiscoAddr, 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
> + * */
> +static void amt_send_relay_request( stream_t *p_access, char *relay_ip
> )
> +{
> + char chaSendBuffer[AMT_REQUEST_MSG_LEN];
> + uint32_t ulNonce;
> + int nRet;
> + access_sys_t *sys = p_access->p_sys;
> +
> + memset( chaSendBuffer, 0, sizeof(chaSendBuffer) );
> +
> + ulNonce = 0;
> + nRet = 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( &chaSendBuffer[4], &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 |
> +*
> +----------------------------------------------------------------------------------+
> +*/
> +static 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;
> + size_t shift = 0;
> + access_sys_t *sys = p_access->p_sys;
> +
> + memset( pSendBuffer, 0, sizeof(pSendBuffer) );
> +
> + pSendBuffer[0] = AMT_MEM_UPD;
> + shift += 2;
> +
> + /* copy relay MAC response */
> + memcpy( &pSendBuffer[shift], sys->relay_mem_query_msg.uchaMAC,
> MAC_LEN );
> + shift += MAC_LEN;
> +
> + /* copy nonce */
> + ulNonce = ntohl(sys->glob_ulNonce);
> + memcpy( &pSendBuffer[shift], &ulNonce, NONCE_LEN );
> + shift += NONCE_LEN;
> +
> + /* make IP header for IGMP packet */
> + amt_ip_alert_t ipHead;
> + memset( &ipHead, 0, IP_HDR_IGMP_LEN );
> + make_ip_header( &ipHead );
> +
> + struct sockaddr_in temp;
> + inet_pton( AF_INET, MCAST_ALLHOSTS, &(temp.sin_addr) );
> + ipHead.destAddr = temp.sin_addr.s_addr;
> + ipHead.check = get_checksum( (unsigned short*)&ipHead,
> IP_HDR_IGMP_LEN );
> +
> + amt_igmpv3_groupRecord_t groupRcd;
> + groupRcd.auxDatalen = 0;
> + groupRcd.ssm = sys->mcastGroupAddr.sin_addr.s_addr;
> +
> + if( sys->mcastSrcAddr.sin_addr.s_addr )
> + {
> + groupRcd.type = leave ? AMT_IGMP_BLOCK:AMT_IGMP_INCLUDE;
> + groupRcd.nSrc = htons(1);
> + groupRcd.srcIP[0] = sys->mcastSrcAddr.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;
> + make_report( &p_igmpMemRep );
> +
> + memcpy(&p_igmpMemRep.grp[0], &groupRcd, (int)sizeof(groupRcd) );
> + p_igmpMemRep.checksum = get_checksum( (unsigned
> short*)&p_igmpMemRep, IGMP_REPORT_LEN );
> +
> + amt_membership_update_msg_t memUpdateMsg;
> + memset(&memUpdateMsg, 0, sizeof(memUpdateMsg));
> + memcpy(&memUpdateMsg.ipHead, &ipHead, sizeof(ipHead) );
> + memcpy(&memUpdateMsg.memReport, &p_igmpMemRep,
ipHead and p_igmpMemRep are useless intermediate variables. You coud call make_ip_header() directly on "&memUpdateMsg.ipHead" for example.
> sizeof(p_igmpMemRep) );
> +
> + memcpy( &pSendBuffer[shift], &memUpdateMsg.ipHead,
> sizeof(memUpdateMsg.ipHead) );
> + shift += sizeof(memUpdateMsg.ipHead);
> + memcpy( &pSendBuffer[shift], &memUpdateMsg.memReport,
> sizeof(memUpdateMsg.memReport) );
You missed one of my remarks:
"You can't copy the amt_membership_update_msg_t struct directly since the compiler may pad/pack the struct.
You have to copy each element one by one."
If we keep this current behavior, we may have different kind of issues depending on compiler, versions or optimisations flags...
Therefore, you shoud only manipulate uint8_t *.
You should check how the bitstream project is doing, like this one for example: https://code.videolan.org/videolan/bitstream/blob/master/ietf/rtp.h#L171
> + shift += sizeof(memUpdateMsg.memReport);
> + assert( (int)sizeof(pSendBuffer) <= ( sendBufSize +
> IGMP_REPORT_LEN ) );
> +
> + 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) ~
> + * | |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * */
> +static 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 || len != RELAY_ADV_MSG_LEN)
> + {
> + msg_Err(p_access, "Received message length is not correct");
> + return false;
> + }
> +
> + memcpy( &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( &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( &sys->relay_adv_msg.ipAddr, &pkt[8], 4 );
> +
> + memset( &sys->relayAddr, 0, sizeof(sys->relayAddr) );
> + sys->relayAddr.sin_family = AF_INET;
> + sys->relayAddr.sin_addr.s_addr = sys->relay_adv_msg.ipAddr;
> + sys->relayAddr.sin_port = htons( AMT_PORT );
> +
> + int nRet = connect( sys->sAMT, (struct sockaddr *)&sys->relayAddr,
> sizeof(sys->relayAddr) );
> + 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) |
> + + +
> + | |
> + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + | |
> + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + */
> +static 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 || len != RELAY_QUERY_MSG_LEN)
> + {
> + msg_Err(p_access, "Received message length is not correct");
> + return false;
> + }
> +
> + memcpy( &sys->relay_mem_query_msg.type, &pkt[0], MSG_TYPE_LEN );
> + /* pkt[1] is reserved */
> + memcpy( &sys->relay_mem_query_msg.uchaMAC[0], &pkt[AMT_HDR_LEN],
> MAC_LEN );
> + memcpy( &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);
> +
> + size_t shift = AMT_HDR_LEN + MAC_LEN + NONCE_LEN;
> + memcpy( &sys->relay_ip_hdr, &pkt[shift], IP_HDR_IGMP_LEN );
> +
> + shift += IP_HDR_IGMP_LEN;
> + sys->relay_igmp_query.type = pkt[shift];
> + shift++; assert( shift < RELAY_QUERY_MSG_LEN);
> + sys->relay_igmp_query.max_resp_code = pkt[shift];
> + shift++; assert( shift < RELAY_QUERY_MSG_LEN);
> + memcpy( &sys->relay_igmp_query.checksum, &pkt[shift], 2 );
> + shift += 2; assert( shift < RELAY_QUERY_MSG_LEN);
> + memcpy( &sys->relay_igmp_query.ssmIP, &pkt[shift], 4 );
> + shift += 4; assert( shift < RELAY_QUERY_MSG_LEN);
> + sys->relay_igmp_query.s_qrv = pkt[shift];
> + shift++; assert( shift < RELAY_QUERY_MSG_LEN);
> + if( pkt[shift] == 0 )
> + sys->relay_igmp_query.qqic = 125;
> + else
> + sys->relay_igmp_query.qqic = pkt[shift];
> +
> + shift++; assert( shift < RELAY_QUERY_MSG_LEN);
> + memcpy( &sys->relay_igmp_query.nSrc, &pkt[shift], 2 );
> +
> + // If there are more than 0 sources,
> + // the IGMP query is not a general query and should be dropped.
> + if( sys->relay_igmp_query.nSrc != 0 )
> + {
> + msg_Warn( p_access, "Number of IGMP sources is not zero; not a
> general query." );
> + return false;
> + }
> +
> + /* if a membership thread exists cancel it */
> + if( sys->threadReady )
> + {
> + msg_Dbg( p_access, "Canceling 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
> + * */
> +static int amt_joinSSM_group( stream_t *p_access )
> +{
> + struct ip_mreq_source imr;
> + access_sys_t *sys = p_access->p_sys;
> +
> + imr.imr_multiaddr.s_addr = sys->mcastGroupAddr.sin_addr.s_addr;
> + imr.imr_sourceaddr.s_addr = sys->mcastSrcAddr.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) );
> +}
> +
> +static int amt_joinASM_group( stream_t *p_access )
> +{
> + struct ip_mreq imr;
> + access_sys_t *sys = p_access->p_sys;
> +
> + imr.imr_multiaddr.s_addr = sys->mcastGroupAddr.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.
> + * */
> +static int amt_leaveSSM_group( stream_t *p_access )
> +{
> + struct ip_mreq_source imr;
> + access_sys_t *sys = p_access->p_sys;
> +
> + imr.imr_multiaddr.s_addr = sys->mcastGroupAddr.sin_addr.s_addr;
> + imr.imr_sourceaddr.s_addr = sys->mcastSrcAddr.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) );
> +}
> +
> +/**
> + * Leave ASM group that was joined earlier.
> + * */
> +static int amt_leaveASM_group( stream_t *p_access )
> +{
> + struct ip_mreq imr;
> + access_sys_t *sys = p_access->p_sys;
> +
> + imr.imr_multiaddr.s_addr = sys->mcastGroupAddr.sin_addr.s_addr;
> + imr.imr_interface.s_addr = INADDR_ANY;
> +
> + return setsockopt( sys->sAMT, IPPROTO_IP, IP_DROP_MEMBERSHIP,
> (char *)&imr, sizeof(imr) );
> +}
> +
> +/* A thread is spawned since IGMP membership updates need to issued
> periodically in order to continue to receive multicast */
> +/* Simple timers are not suitable for this requirement since the
> parent is otherwise occupied in receiving UDP packet flow */
> +static void *amt_mem_upd( void *data )
> +{
> + 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" );
> +
> + /* thread sends periodic AMT membership updates until Close()
> which terminates thread */
> + while ( true )
> + {
> + amt_send_mem_update( p_access, sys->relayDisco, false );
> + vlc_tick_sleep( (vlc_tick_t)sys->relay_igmp_query.qqic *
> CLOCK_FREQ );
> + }
> +
> + return NULL;
> +}
> --
> 2.20.1 (Apple Git-117)
>
> _______________________________________________
> vlc-devel mailing list
> To unsubscribe or modify your subscription options:
> https://mailman.videolan.org/listinfo/vlc-devel
More information about the vlc-devel
mailing list