modules/stream_out/sdp_helper.c

   1 /*****************************************************************************
   2  * sdp.c : SDP creation helpers
   3  *****************************************************************************
   4  * Copyright © 2007 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 #include <string.h>
  26
  27 #include <vlc_common.h>
  28 #include <vlc_charset.h>
  29 #include <vlc_network.h>
  30 #include <vlc_memstream.h>
  31
  32 #include "sdp_helper.h"
  33
  34 #define MAXSDPADDRESS 47
  35
  36 static
  37 char *AddressToSDP (const struct sockaddr *addr, size_t addrlen, char *buf)
  38 {
  39     if (addrlen < offsetof (struct sockaddr, sa_family)
  40                  + sizeof (addr->sa_family))
  41         return NULL;
  42
  43     strcpy (buf, "IN IP* ");
  44
  45     if (vlc_getnameinfo (addr, addrlen, buf + 7, MAXSDPADDRESS - 7, NULL,
  46                          NI_NUMERICHOST))
  47         return NULL;
  48
  49     switch (addr->sa_family)
  50     {
  51         case AF_INET:
  52         {
  53             if (net_SockAddrIsMulticast (addr, addrlen))
  54                 strcat (buf, "/255"); // obsolete in RFC4566, dummy value
  55             buf[5] = '4';
  56             break;
  57         }
  58
  59 #ifdef AF_INET6
  60         case AF_INET6:
  61         {
  62             char *ptr = strchr (buf, '%');
  63             if (ptr != NULL)
  64                 *ptr = '\0'; // remove scope ID
  65             buf[5] = '6';
  66             break;
  67         }
  68 #endif
  69
  70         default:
  71             return NULL;
  72     }
  73
  74     return buf;
  75 }
  76
  77
  78 static bool IsSDPString (const char *str)
  79 {
  80     if (strchr (str, '\r') != NULL)
  81         return false;
  82     if (strchr (str, '\n') != NULL)
  83         return false;
  84     if (!IsUTF8 (str))
  85         return false;
  86     return true;
  87 }
  88
  89 int vlc_sdp_Start(struct vlc_memstream *restrict stream,
  90                   vlc_object_t *obj, const char *cfgpref,
  91                   const struct sockaddr *src, size_t srclen,
  92                   const struct sockaddr *addr, size_t addrlen)
  93 {
  94     char connection[MAXSDPADDRESS];
  95     char *str = NULL;
  96
  97     size_t cfglen = strlen(cfgpref);
  98     if (cfglen >= 128)
  99         return -1;
 100
 101     char varname[cfglen + sizeof ("description")];
 102     char *subvar = varname + cfglen;
 103
 104     strcpy(varname, cfgpref);
 105
 106     vlc_memstream_open(stream);
 107     vlc_memstream_puts(stream, "v=0\r\n");
 108
 109     if (AddressToSDP(addr, addrlen, connection) == NULL)
 110         goto error;
 111     {
 112         const uint_fast64_t now = NTPtime64();
 113         char hostname[256];
 114
 115         gethostname(hostname, sizeof (hostname));
 116
 117         vlc_memstream_printf(stream, "o=- %"PRIu64" %"PRIu64" IN IP%c %s\r\n",
 118                              now, now, connection[5], hostname);
 119     }
 120
 121     strcpy(subvar, "name");
 122     str = var_GetNonEmptyString(obj, varname);
 123     if (str != NULL)
 124     {
 125         if (!IsSDPString(str))
 126             goto error;
 127
 128         vlc_memstream_printf(stream, "s=%s\r\n", str);
 129         free(str);
 130     }
 131     else
 132         vlc_memstream_printf(stream, "s=%s\r\n", "Unnamed");
 133
 134     strcpy(subvar, "description");
 135     str = var_GetNonEmptyString(obj, varname);
 136     if (str != NULL)
 137     {
 138         if (!IsSDPString(str))
 139             goto error;
 140
 141         vlc_memstream_printf(stream, "i=%s\r\n", str);
 142         free(str);
 143     }
 144
 145     // no URL, email, no phone (useless)
 146
 147     vlc_memstream_printf(stream, "c=%s\r\n", connection);
 148     // bandwidth not specified
 149     vlc_memstream_puts(stream, "t=0 0\r\n"); // one dummy time span
 150     // no repeating
 151     // no time zone adjustment (silly idea anyway)
 152     // no encryption key (deprecated)
 153
 154     vlc_memstream_printf(stream, "a=tool:%s\r\n", PACKAGE_STRING);
 155     vlc_memstream_puts(stream, "a=recvonly\r\n");
 156     vlc_memstream_puts(stream, "a=type:broadcast\r\n");
 157     vlc_memstream_puts(stream, "a=charset:UTF-8\r\n");
 158
 159     if (srclen > 0)
 160     {
 161         char machine[MAXSDPADDRESS];
 162
 163         if (AddressToSDP(src, srclen, machine) != NULL)
 164             vlc_memstream_printf(stream,
 165                                  "a=source-filter: incl IN IP%c * %s\r\n",
 166                                  machine[5], machine + 7);
 167     }
 168
 169     strcpy(subvar, "cat");
 170     str = var_GetNonEmptyString(obj, varname);
 171     if (str != NULL)
 172     {
 173         if (IsSDPString(str))
 174             goto error;
 175
 176         vlc_memstream_printf(stream, "a=cat:%s\r\n", str);
 177         vlc_memstream_printf(stream, "a=x-plgroup:%s\r\n", str);
 178         free(str);
 179     }
 180     return 0;
 181 error:
 182     free(str);
 183     if (vlc_memstream_close(stream) == 0)
 184         free(stream->ptr);
 185     return -1;
 186 }