src/stream_output/sdp.c

   1 /*****************************************************************************
   2  * sdp.c : SDP creation helpers
   3  *****************************************************************************
   4  * Copyright © 2007 Rémi Denis-Courmont
   5  * $Id$
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this program; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  20  *****************************************************************************/
  21
  22 #ifdef HAVE_CONFIG_H
  23 # include "config.h"
  24 #endif
  25
  26 #include <vlc_common.h>
  27
  28 #include <stddef.h>
  29 #include <string.h>
  30 #include <stdarg.h>
  31 #include <stdio.h>
  32 #include <assert.h>
  33 #include <vlc_network.h>
  34 #include <vlc_charset.h>
  35 #include <vlc_memstream.h>
  36
  37 #include "stream_output.h"
  38
  39 #define MAXSDPADDRESS 47
  40
  41 static
  42 char *AddressToSDP (const struct sockaddr *addr, socklen_t addrlen, char *buf)
  43 {
  44     if (addrlen < offsetof (struct sockaddr, sa_family)
  45                  + sizeof (addr->sa_family))
  46         return NULL;
  47
  48     strcpy (buf, "IN IP* ");
  49
  50     if (vlc_getnameinfo (addr, addrlen, buf + 7, MAXSDPADDRESS - 7, NULL,
  51                          NI_NUMERICHOST))
  52         return NULL;
  53
  54     switch (addr->sa_family)
  55     {
  56         case AF_INET:
  57         {
  58             if (net_SockAddrIsMulticast (addr, addrlen))
  59                 strcat (buf, "/255"); // obsolete in RFC4566, dummy value
  60             buf[5] = '4';
  61             break;
  62         }
  63
  64 #ifdef AF_INET6
  65         case AF_INET6:
  66         {
  67             char *ptr = strchr (buf, '%');
  68             if (ptr != NULL)
  69                 *ptr = '\0'; // remove scope ID
  70             buf[5] = '6';
  71             break;
  72         }
  73 #endif
  74
  75         default:
  76             return NULL;
  77     }
  78
  79     return buf;
  80 }
  81
  82
  83 static bool IsSDPString (const char *str)
  84 {
  85     if (strchr (str, '\r') != NULL)
  86         return false;
  87     if (strchr (str, '\n') != NULL)
  88         return false;
  89     if (!IsUTF8 (str))
  90         return false;
  91     return true;
  92 }
  93
  94 static void vsdp_AddAttribute(struct vlc_memstream *restrict stream,
  95                               const char *name, const char *fmt, va_list ap)
  96 {
  97     vlc_memstream_printf(stream, "a=%s:", name);
  98     vlc_memstream_vprintf(stream, fmt, ap);
  99     vlc_memstream_puts(stream, "\r\n");
 100 }
 101
 102 void sdp_AddAttribute(struct vlc_memstream *restrict stream, const char *name,
 103                       const char *fmt, ...)
 104 {
 105     va_list ap;
 106
 107     va_start(ap, fmt);
 108     vsdp_AddAttribute(stream, name, fmt, ap);
 109     va_end(ap);
 110 }
 111
 112 void sdp_AddMedia(struct vlc_memstream *restrict stream,
 113                   const char *type, const char *proto, int dport,
 114                   unsigned pt, bool bw_indep, unsigned bw,
 115                   const char *ptname, unsigned clock, unsigned chans,
 116                   const char *fmtp)
 117 {
 118     /* Some default values */
 119     if (type == NULL)
 120         type = "video";
 121     if (proto == NULL)
 122         proto = "RTP/AVP";
 123     assert (pt < 128u);
 124
 125     vlc_memstream_printf(stream, "m=%s %u %s %u\r\n", type, dport, proto, pt);
 126
 127     if (bw > 0)
 128         vlc_memstream_printf(stream, "b=%s:%u\r\n",
 129                              bw_indep ? "TIAS" : "AS", bw);
 130     vlc_memstream_printf(stream, "b=%s:%u\r\n", "RR", 0);
 131
 132     /* RTP payload type map */
 133     if (ptname != NULL)
 134     {
 135         vlc_memstream_printf(stream, "a=rtpmap:%u %s/%u", pt, ptname, clock);
 136         if ((strcmp(type, "audio") == 0) && (chans != 1))
 137             vlc_memstream_printf(stream, "/%u", chans);
 138         vlc_memstream_puts(stream, "\r\n");
 139     }
 140
 141     /* Format parameters */
 142     if (fmtp != NULL)
 143         vlc_memstream_printf(stream, "a=fmtp:%u %s\r\n", pt, fmtp);
 144 }
 145
 146 int vlc_sdp_Start(struct vlc_memstream *restrict stream,
 147                   vlc_object_t *obj, const char *cfgpref,
 148                   const struct sockaddr *src, size_t srclen,
 149                   const struct sockaddr *addr, size_t addrlen)
 150 {
 151     char connection[MAXSDPADDRESS];
 152     char *str = NULL;
 153
 154     size_t cfglen = strlen(cfgpref);
 155     if (cfglen >= 128)
 156         return -1;
 157
 158     char varname[cfglen + sizeof ("description")];
 159     char *subvar = varname + cfglen;
 160
 161     strcpy(varname, cfgpref);
 162
 163     vlc_memstream_open(stream);
 164     vlc_memstream_puts(stream, "v=0\r\n");
 165
 166     if (AddressToSDP(addr, addrlen, connection) == NULL)
 167         goto error;
 168     {
 169         const uint_fast64_t now = NTPtime64();
 170         char hostname[256];
 171
 172         gethostname(hostname, sizeof (hostname));
 173
 174         vlc_memstream_printf(stream, "o=- %"PRIu64" %"PRIu64" IN IP%c %s\r\n",
 175                              now, now, connection[5], hostname);
 176     }
 177
 178     strcpy(subvar, "name");
 179     str = var_GetNonEmptyString(obj, varname);
 180     if (str != NULL)
 181     {
 182         if (!IsSDPString(str))
 183             goto error;
 184
 185         vlc_memstream_printf(stream, "s=%s\r\n", str);
 186         free(str);
 187     }
 188     else
 189         vlc_memstream_printf(stream, "s=%s\r\n", "Unnamed");
 190
 191     strcpy(subvar, "description");
 192     str = var_GetNonEmptyString(obj, varname);
 193     if (str != NULL)
 194     {
 195         if (!IsSDPString(str))
 196             goto error;
 197
 198         vlc_memstream_printf(stream, "i=%s\r\n", str);
 199         free(str);
 200     }
 201     else
 202         vlc_memstream_printf(stream, "i=%s\r\n", "N/A");
 203
 204     strcpy(subvar, "url");
 205     str = var_GetNonEmptyString(obj, varname);
 206     if (str != NULL)
 207     {
 208         if (!IsSDPString(str))
 209             goto error;
 210
 211         vlc_memstream_printf(stream, "u=%s\r\n", str);
 212         free(str);
 213     }
 214
 215     strcpy(subvar, "email");
 216     str = var_GetNonEmptyString(obj, varname);
 217     if (str != NULL)
 218     {
 219         if (!IsSDPString(str))
 220             goto error;
 221
 222         vlc_memstream_printf(stream, "e=%s\r\n", str);
 223         free(str);
 224     }
 225
 226     // no phone (useless)
 227
 228     vlc_memstream_printf(stream, "c=%s\r\n", connection);
 229     // bandwidth not specified
 230     vlc_memstream_puts(stream, "t=0 0\r\n"); // one dummy time span
 231     // no repeating
 232     // no time zone adjustment (silly idea anyway)
 233     // no encryption key (deprecated)
 234
 235     vlc_memstream_printf(stream, "a=tool:%s\r\n", PACKAGE_STRING);
 236     vlc_memstream_puts(stream, "a=recvonly\r\n");
 237     vlc_memstream_puts(stream, "a=type:broadcast\r\n");
 238     vlc_memstream_puts(stream, "a=charset:UTF-8\r\n");
 239
 240     if (srclen > 0)
 241     {
 242         char machine[MAXSDPADDRESS];
 243
 244         if (AddressToSDP(src, srclen, machine) != NULL)
 245             vlc_memstream_printf(stream,
 246                                  "a=source-filter: incl IN IP%c * %s\r\n",
 247                                  machine[5], machine + 7);
 248     }
 249
 250     strcpy(subvar, "cat");
 251     str = var_GetNonEmptyString(obj, varname);
 252     if (str != NULL)
 253     {
 254         if (IsSDPString(str))
 255             goto error;
 256
 257         vlc_memstream_printf(stream, "a=cat:%s\r\n", str);
 258         vlc_memstream_printf(stream, "a=x-plgroup:%s\r\n", str);
 259         free(str);
 260     }
 261     return 0;
 262 error:
 263     free(str);
 264     if (vlc_memstream_close(stream) == 0)
 265         free(stream->ptr);
 266     return -1;
 267 }