-
Typos found and reworked from codespell.
6b7a57f9
sap.c 19.55 KiB
/*****************************************************************************
* sap.c : SAP interface module
*****************************************************************************
* Copyright (C) 2004-2005 the VideoLAN team
* Copyright © 2007 Rémi Denis-Courmont
*
* Authors: Clément Stenac <zorglub@videolan.org>
* Rémi Denis-Courmont
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* Includes
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#define VLC_MODULE_LICENSE VLC_LICENSE_GPL_2_PLUS
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <assert.h>
#include <vlc_demux.h>
#include <vlc_services_discovery.h>
#include <vlc_network.h>
#include <vlc_charset.h>
#include <errno.h>
#include <unistd.h>
#ifdef HAVE_ARPA_INET_H
# include <arpa/inet.h>
#endif
#ifdef HAVE_POLL_H
# include <poll.h>
#endif
#ifdef HAVE_ZLIB_H
# include <zlib.h>
#endif
#ifdef HAVE_NET_IF_H
# include <net/if.h>
#endif
#include "access/rtp/sdp.h"
/************************************************************************
* Macros and definitions
************************************************************************/
#define MAX_LINE_LENGTH 256
/* SAP is always on that port */
#define SAP_PORT 9875
/* Global-scope SAP address */#define SAP_V4_GLOBAL_ADDRESS "224.2.127.254"
/* Organization-local SAP address */
#define SAP_V4_ORG_ADDRESS "239.195.255.255"
/* Local (smallest non-link-local scope) SAP address */
#define SAP_V4_LOCAL_ADDRESS "239.255.255.255"
/* Link-local SAP address */
#define SAP_V4_LINK_ADDRESS "224.0.0.255"
#define ADD_SESSION 1
static int Decompress( const unsigned char *psz_src, unsigned char **_dst, int i_len )
{
#ifdef HAVE_ZLIB_H
int i_result, i_dstsize, n = 0;
unsigned char *psz_dst = NULL;
z_stream d_stream;
memset (&d_stream, 0, sizeof (d_stream));
i_result = inflateInit(&d_stream);
if( i_result != Z_OK )
return( -1 );
d_stream.next_in = (Bytef *)psz_src;
d_stream.avail_in = i_len;
do
{
n++;
psz_dst = xrealloc( psz_dst, n * 1000 );
d_stream.next_out = (Bytef *)&psz_dst[(n - 1) * 1000];
d_stream.avail_out = 1000;
i_result = inflate(&d_stream, Z_NO_FLUSH);
if( ( i_result != Z_OK ) && ( i_result != Z_STREAM_END ) )
{
inflateEnd( &d_stream );
free( psz_dst );
return( -1 );
}
}
while( ( d_stream.avail_out == 0 ) && ( d_stream.avail_in != 0 ) &&
( i_result != Z_STREAM_END ) );
i_dstsize = d_stream.total_out;
inflateEnd( &d_stream );
*_dst = xrealloc( psz_dst, i_dstsize );
return i_dstsize;
#else
(void)psz_src;
(void)_dst;
(void)i_len;
return -1;
#endif
}
typedef struct sap_announce_t
{
vlc_tick_t i_last;
vlc_tick_t i_period;
uint8_t i_period_trust;
uint16_t i_hash;
uint32_t i_source[4];
input_item_t * p_item;
} sap_announce_t;
static sap_announce_t *CreateAnnounce(services_discovery_t *p_sd, const uint32_t *i_source,
uint16_t i_hash, const char *psz_sdp)
{
/* Parse SDP info */
struct vlc_sdp *p_sdp = vlc_sdp_parse(psz_sdp, strlen(psz_sdp));
if (p_sdp == NULL)
return NULL;
char *uri = NULL;
if (asprintf(&uri, "sdp://%s", psz_sdp) == -1)
{
vlc_sdp_free(p_sdp);
return NULL;
}
input_item_t *p_input;
const char *psz_value;
sap_announce_t *p_sap = malloc(sizeof (*p_sap));
if( p_sap == NULL )
return NULL;
p_sap->i_last = vlc_tick_now();
p_sap->i_period = 0;
p_sap->i_period_trust = 0;
p_sap->i_hash = i_hash;
memcpy (p_sap->i_source, i_source, sizeof(p_sap->i_source));
/* Released in RemoveAnnounce */
p_input = input_item_NewStream(uri, p_sdp->name,
INPUT_DURATION_INDEFINITE);
if( unlikely(p_input == NULL) )
{
free( p_sap );
return NULL;
}
p_sap->p_item = p_input;
vlc_meta_t *p_meta = vlc_meta_New();
if( likely(p_meta != NULL) )
{
vlc_meta_Set(p_meta, vlc_meta_Description, p_sdp->info);
p_input->p_meta = p_meta;
}
psz_value = vlc_sdp_attr_value(p_sdp, "tool");
if( psz_value != NULL )
{
input_item_AddInfo( p_input, _("Session"), _("Tool"), "%s", psz_value );
}
/* Handle category */
psz_value = vlc_sdp_attr_value(p_sdp, "cat");
if (psz_value != NULL)
{
/* a=cat provides a dot-separated hierarchy.
* For the time being only replace dots with pipe. TODO: FIXME */
char *str = strdup(psz_value);
if (likely(str != NULL))
for (char *p = strchr(str, '.'); p != NULL; p = strchr(p, '.'))
*(p++) = '|';
services_discovery_AddItemCat(p_sd, p_input, str ? str : psz_value);
free(str);
}
else
{
/* backward compatibility with VLC 0.7.3-2.0.0 senders */
psz_value = vlc_sdp_attr_value(p_sdp, "x-plgroup");
services_discovery_AddItemCat(p_sd, p_input, psz_value);
}
vlc_sdp_free(p_sdp);
return p_sap;
}
typedef struct
{
vlc_thread_t thread;
/* Socket descriptors */
int i_fd;
int *pi_fd;
/* Table of announces */
int i_announces;
struct sap_announce_t **pp_announces;
vlc_tick_t i_timeout;
} services_discovery_sys_t;
static int RemoveAnnounce( services_discovery_t *p_sd,
sap_announce_t *p_announce )
{
if( p_announce->p_item )
{
services_discovery_RemoveItem( p_sd, p_announce->p_item );
input_item_Release( p_announce->p_item );
p_announce->p_item = NULL;
}
services_discovery_sys_t *p_sys = p_sd->p_sys;
TAB_REMOVE(p_sys->i_announces, p_sys->pp_announces, p_announce);
free( p_announce );
return VLC_SUCCESS;
}
static int InitSocket( services_discovery_t *p_sd, const char *psz_address,
int i_port )
{
int i_fd = net_ListenUDP1 ((vlc_object_t *)p_sd, psz_address, i_port);
if (i_fd == -1)
return VLC_EGENERIC;
shutdown( i_fd, SHUT_WR );
services_discovery_sys_t *p_sys = p_sd->p_sys;
TAB_APPEND(p_sys->i_fd, p_sys->pi_fd, i_fd);
return VLC_SUCCESS;
}
/* i_read is at least > 6 */
static int ParseSAP( services_discovery_t *p_sd, const uint8_t *buf,
size_t len )
{
services_discovery_sys_t *p_sys = p_sd->p_sys;
const char *psz_sdp;
const uint8_t *end = buf + len;
uint32_t i_source[4];
assert (buf[len] == '\0');
if (len < 4)
return VLC_EGENERIC;
uint8_t flags = buf[0];
uint8_t auth_len = buf[1];
/* First, check the sap announce is correct */
if ((flags >> 5) != 1)
return VLC_EGENERIC;
bool b_ipv6 = (flags & 0x10) != 0;
bool b_need_delete = (flags & 0x04) != 0;
if (flags & 0x02)
{
msg_Dbg( p_sd, "encrypted packet, unsupported" );
return VLC_EGENERIC;
}
bool b_compressed = (flags & 0x01) != 0;
uint16_t i_hash = U16_AT (buf + 2);
if( i_hash == 0 )
return VLC_EGENERIC;
buf += 4;
if( b_ipv6 )
{
for( int i = 0; i < 4; i++,buf+=4)
i_source[i] = U32_AT(buf);
}
else
{
memset(i_source, 0, sizeof(i_source));
i_source[3] = U32_AT(buf);
buf+=4;
}
// Skips auth data
buf += auth_len;
if (buf > end)
return VLC_EGENERIC;
uint8_t *decomp = NULL;
if( b_compressed )
{
int newsize = Decompress (buf, &decomp, end - buf);
if (newsize < 0)
{
msg_Dbg( p_sd, "decompression of SAP packet failed" );
return VLC_EGENERIC;
}
decomp = xrealloc (decomp, newsize + 1);
decomp[newsize] = '\0';
psz_sdp = (const char *)decomp;
len = newsize;
}
else
{
psz_sdp = (const char *)buf;
len = end - buf;
}
/* len is a strlen here here. both buf and decomp are len+1 where the 1 should be a \0 */
assert( psz_sdp[len] == '\0');
/* Skip payload type */
/* SAPv1 has implicit "application/sdp" payload type: first line is v=0 */
if (strncmp (psz_sdp, "v=0", 3))
{
size_t clen = strlen (psz_sdp) + 1;
if (strcmp (psz_sdp, "application/sdp"))
{
msg_Dbg (p_sd, "unsupported content type: %s", psz_sdp);
goto error;
}
// skips content type
if (len <= clen)
goto error;
len -= clen;
psz_sdp += clen;
}
for( int i = 0 ; i < p_sys->i_announces ; i++ )
{
sap_announce_t * p_announce = p_sys->pp_announces[i];
/* FIXME: slow */
if (p_announce->i_hash == i_hash
&& memcmp(p_announce->i_source, i_source, sizeof (i_source)) == 0)
{
/* We don't support delete announcement as they can easily
* Be used to hijack an announcement by a third party.
* Instead we cleverly implement Implicit Announcement removal.
*
* if( b_need_delete )
* RemoveAnnounce( p_sd, p_sys->pp_announces[i]);
* else
*/
if( !b_need_delete )
{
/* No need to go after six, as we start to trust the
* average period at six */
if( p_announce->i_period_trust <= 5 )
p_announce->i_period_trust++;
/* Compute the average period */
vlc_tick_t now = vlc_tick_now();
p_announce->i_period = ( p_announce->i_period * (p_announce->i_period_trust-1) + (now - p_announce->i_last) ) / p_announce->i_period_trust;
p_announce->i_last = now;
}
free (decomp);
return VLC_SUCCESS;
}
}
sap_announce_t *sap = CreateAnnounce(p_sd, i_source, i_hash, psz_sdp);
if (sap != NULL)
TAB_APPEND(p_sys->i_announces, p_sys->pp_announces, sap);
free (decomp);
return VLC_SUCCESS;
error:
free (decomp);
return VLC_EGENERIC;
}
/*****************************************************************************
* Run: main SAP thread
*****************************************************************************
* Listens to SAP packets, and sends them to packet_handle
*****************************************************************************/
#define MAX_SAP_BUFFER 5000
static void *Run( void *data )
{
services_discovery_t *p_sd = data;
services_discovery_sys_t *p_sys = p_sd->p_sys;
char *psz_addr;
int timeout = -1;
int canc = vlc_savecancel ();
/* Braindead Winsock DNS resolver will get stuck over 2 seconds per failed
* DNS queries, even if the DNS server returns an error with milliseconds.
* You don't want to know why the bug (as of XP SP2) wasn't fixed since * Winsock 1.1 from Windows 95, if not Windows 3.1.
* Anyway, to avoid a 30 seconds delay for failed IPv6 socket creation,
* we have to open sockets in Run() rather than Open(). */
InitSocket( p_sd, SAP_V4_GLOBAL_ADDRESS, SAP_PORT );
InitSocket( p_sd, SAP_V4_ORG_ADDRESS, SAP_PORT );
InitSocket( p_sd, SAP_V4_LOCAL_ADDRESS, SAP_PORT );
InitSocket( p_sd, SAP_V4_LINK_ADDRESS, SAP_PORT );
char psz_address[NI_MAXNUMERICHOST] = "ff02::2:7ffe%";
#ifndef _WIN32
struct if_nameindex *l = if_nameindex ();
if (l != NULL)
{
char *ptr = strchr (psz_address, '%') + 1;
for (unsigned i = 0; l[i].if_index; i++)
{
strcpy (ptr, l[i].if_name);
InitSocket (p_sd, psz_address, SAP_PORT);
}
if_freenameindex (l);
}
#else
/* this is the Winsock2 equivalent of SIOCGIFCONF on BSD stacks,
which if_nameindex uses internally anyway */
// first create a dummy socket to pin down the protocol family
SOCKET s = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
if( s != INVALID_SOCKET )
{
INTERFACE_INFO ifaces[10]; // Assume there will be no more than 10 IP interfaces
DWORD len = sizeof(ifaces);
if( SOCKET_ERROR != WSAIoctl(s, SIO_GET_INTERFACE_LIST, NULL, 0, &ifaces, len, &len, NULL, NULL) )
{
unsigned ifcount = len/sizeof(INTERFACE_INFO);
char *ptr = strchr (psz_address, '%') + 1;
for(unsigned i = 1; i<=ifcount; ++i )
{
// append link-local zone identifier
sprintf(ptr, "%d", i);
}
}
closesocket(s);
}
#endif
*strchr (psz_address, '%') = '\0';
static const char ipv6_scopes[] = "1456789ABCDE";
for (const char *c_scope = ipv6_scopes; *c_scope; c_scope++)
{
psz_address[3] = *c_scope;
InitSocket( p_sd, psz_address, SAP_PORT );
}
psz_addr = var_CreateGetString( p_sd, "sap-addr" );
if( psz_addr && *psz_addr )
InitSocket( p_sd, psz_addr, SAP_PORT );
free( psz_addr );
if( p_sys->i_fd == 0 )
{
msg_Err( p_sd, "unable to listen on any address" );
return NULL;
}
/* read SAP packets */
for (;;)
{
vlc_restorecancel (canc);
unsigned n = p_sys->i_fd; struct pollfd ufd[n];
for (unsigned i = 0; i < n; i++)
{
ufd[i].fd = p_sys->pi_fd[i];
ufd[i].events = POLLIN;
ufd[i].revents = 0;
}
int val = poll (ufd, n, timeout);
canc = vlc_savecancel ();
if (val > 0)
{
for (unsigned i = 0; i < n; i++)
{
if (ufd[i].revents)
{
uint8_t p_buffer[MAX_SAP_BUFFER+1];
ssize_t i_read;
i_read = recv (ufd[i].fd, p_buffer, MAX_SAP_BUFFER, 0);
if (i_read < 0)
msg_Warn (p_sd, "receive error: %s",
vlc_strerror_c(errno));
if (i_read > 6)
{
/* Parse the packet */
p_buffer[i_read] = '\0';
ParseSAP (p_sd, p_buffer, i_read);
}
}
}
}
vlc_tick_t now = vlc_tick_now();
/* A 1 hour timeout correspond to the RFC Implicit timeout.
* This timeout is tuned in the following loop. */
timeout = 1000 * 60 * 60;
/* Check for items that need deletion */
for( int i = 0; i < p_sys->i_announces; i++ )
{
sap_announce_t * p_announce = p_sys->pp_announces[i];
vlc_tick_t i_last_period = now - p_announce->i_last;
/* Remove the announcement, if the last announcement was 1 hour ago
* or if the last packet emitted was 10 times the average time
* between two packets */
if( ( p_announce->i_period_trust > 5 && i_last_period > 10 * p_announce->i_period ) ||
i_last_period > p_sys->i_timeout )
{
RemoveAnnounce( p_sd, p_announce );
}
else
{
/* Compute next timeout */
if( p_announce->i_period_trust > 5 )
timeout = __MIN(MS_FROM_VLC_TICK(10 * p_announce->i_period - i_last_period), timeout);
timeout = __MIN(MS_FROM_VLC_TICK(p_sys->i_timeout - i_last_period), timeout);
}
}
if( !p_sys->i_announces )
timeout = -1; /* We can safely poll indefinitely. */
else if( timeout < 200 )
timeout = 200; /* Don't wakeup too fast. */
}
vlc_assert_unreachable ();
}
/*****************************************************************************
* Open: initialize and create stuff
*****************************************************************************/
static int Open( vlc_object_t *p_this )
{
services_discovery_t *p_sd = ( services_discovery_t* )p_this;
services_discovery_sys_t *p_sys = (services_discovery_sys_t *)
malloc( sizeof( services_discovery_sys_t ) );
if( !p_sys )
return VLC_ENOMEM;
p_sys->i_timeout = vlc_tick_from_sec(var_CreateGetInteger( p_sd, "sap-timeout" ));
p_sd->p_sys = p_sys;
p_sd->description = _("Network streams (SAP)");
p_sys->pi_fd = NULL;
p_sys->i_fd = 0;
p_sys->i_announces = 0;
p_sys->pp_announces = NULL;
/* TODO: create sockets here, and fix racy sockets table */
if (vlc_clone (&p_sys->thread, Run, p_sd, VLC_THREAD_PRIORITY_LOW))
{
free (p_sys);
return VLC_EGENERIC;
}
return VLC_SUCCESS;
}
/*****************************************************************************
* Close:
*****************************************************************************/
static void Close( vlc_object_t *p_this )
{
services_discovery_t *p_sd = ( services_discovery_t* )p_this;
services_discovery_sys_t *p_sys = p_sd->p_sys;
int i;
vlc_cancel (p_sys->thread);
vlc_join (p_sys->thread, NULL);
for( i = p_sys->i_fd-1 ; i >= 0 ; i-- )
{
net_Close( p_sys->pi_fd[i] );
}
FREENULL( p_sys->pi_fd );
for( i = p_sys->i_announces - 1; i>= 0; i-- )
{
RemoveAnnounce( p_sd, p_sys->pp_announces[i] );
}
FREENULL( p_sys->pp_announces );
free( p_sys );
}
/*****************************************************************************
* Module descriptor
*****************************************************************************/
#define SAP_ADDR_TEXT N_( "SAP multicast address" )
#define SAP_ADDR_LONGTEXT N_( "The SAP module normally chooses itself the " \
"right addresses to listen to. However, you " \
"can specify a specific address." )
#define SAP_TIMEOUT_TEXT N_( "SAP timeout (seconds)" )
#define SAP_TIMEOUT_LONGTEXT N_( \
"Delay after which SAP items get deleted if no new announcement " \
"is received." )#define SAP_PARSE_TEXT N_( "Try to parse the announce" )
#define SAP_PARSE_LONGTEXT N_( \
"This enables actual parsing of the announces by the SAP module. " \
"Otherwise, all announcements are parsed by the \"live555\" " \
"(RTP/RTSP) module." )
VLC_SD_PROBE_HELPER("sap", N_("Network streams (SAP)"), SD_CAT_LAN)
vlc_module_begin()
set_shortname(N_("SAP"))
set_description(N_("Network streams (SAP)") )
set_subcategory(SUBCAT_PLAYLIST_SD)
add_string("sap-addr", NULL, SAP_ADDR_TEXT, SAP_ADDR_LONGTEXT)
add_integer("sap-timeout", 1800,
SAP_TIMEOUT_TEXT, SAP_TIMEOUT_LONGTEXT)
add_obsolete_bool("sap-parse") /* since 4.0.0 */
add_obsolete_bool("sap-strict") /* since 4.0.0 */
set_capability("services_discovery", 0)
set_callbacks(Open, Close)
VLC_SD_PROBE_SUBMODULE
vlc_module_end()