soa_static.c

Sofia SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification.

/*
 * This file is part of the Sofia-SIP package
 *
 * Copyright (C) 2006 Nokia Corporation.
 *
 * Contact: Pekka Pessi <[e-mail]>
 *
 * 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
 *
 */

/**@CFILE soa_static.c
 *
 * @brief Static implementation of Sofia SDP Offer/Answer Engine
 *
 * @author Pekka Pessi <[e-mail]>
 *
 * @date Created: Tue Aug 16 17:06:06 EEST 2005
 *
 * @par Use-cases
 *  1. no existing session
 *    a) generating offer (upgrade with user-SDP)
 *    b) generating answer (upgrade with remote-SDP, rejects with user-SDP)
 *  2. session exists
 *    a) generating offer: 
 *       upgrades with user-SDP
 *    b) generating answer: 
 *       upgrades with remote-SDP, rejects with user-SDP
 *    c) processing answer: 
 *       rejects with user-SDP, no upgrades
 *
 * Upgrading session with user SDP:
 */

#include "config.h"

#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include <assert.h>

struct soa_static_complete;

#define SU_MSG_ARG_T struct soa_static_completed

#include <sofia-sip/su_wait.h>
#include <sofia-sip/su_tag_class.h>
#include <sofia-sip/su_tag_class.h>
#include <sofia-sip/su_tagarg.h>
#include <sofia-sip/su_strlst.h>
#include <sofia-sip/string0.h>
#include <sofia-sip/bnf.h>

#include "sofia-sip/soa.h"
#include <sofia-sip/sdp.h>
#include "sofia-sip/soa_session.h"

#define NONE ((void *)-1)
#define XXX assert(!"implemented")

#if !HAVE_STRCASESTR
char *strcasestr(const char *haystack, const char *needle);
#endif

typedef struct soa_static_session
{
  soa_session_t sss_session[1];
  char *sss_audio_aux;
  int sss_ordered_user;  /**< User SDP is ordered */
  int sss_reuse_rejected; /**< Try to reuse rejected media line slots */

  /** Mapping from user SDP m= lines to session SDP m= lines */
  int  *sss_u2s;
  /** Mapping from session SDP m= lines to user SDP m= lines */
  int *sss_s2u;
}
soa_static_session_t;

#define U2S_NOT_USED (-1)
#define U2S_SENTINEL (-2)

static int soa_static_init(char const *, soa_session_t *, soa_session_t *);
static void soa_static_deinit(soa_session_t *);
static int soa_static_set_params(soa_session_t *ss, tagi_t const *tags);
static int soa_static_get_params(soa_session_t const *ss, tagi_t *tags);
static tagi_t *soa_static_get_paramlist(soa_session_t const *ss,
					tag_type_t tag, tag_value_t value, 
					...);
static int soa_static_set_capability_sdp(soa_session_t *ss, 
				       sdp_session_t *sdp,
				       char const *, isize_t);
static int soa_static_set_remote_sdp(soa_session_t *ss, 
				   int new_version,
				   sdp_session_t *sdp,
				   char const *, isize_t);
static int soa_static_set_user_sdp(soa_session_t *ss, 
				   sdp_session_t *sdp,
				   char const *, isize_t);
static int soa_static_generate_offer(soa_session_t *ss, soa_callback_f *);
static int soa_static_generate_answer(soa_session_t *ss, soa_callback_f *);
static int soa_static_process_answer(soa_session_t *ss, soa_callback_f *);
static int soa_static_process_reject(soa_session_t *ss, soa_callback_f *);

static int soa_static_activate(soa_session_t *ss, char const *option);
static int soa_static_deactivate(soa_session_t *ss, char const *option);
static void soa_static_terminate(soa_session_t *ss, char const *option);

struct soa_session_actions const soa_default_actions = 
  {
    (sizeof soa_default_actions),
    sizeof (struct soa_static_session),
    "static",
    soa_static_init,
    soa_static_deinit,
    soa_static_set_params,
    soa_static_get_params,
    soa_static_get_paramlist,
    soa_base_media_features,
    soa_base_sip_require,
    soa_base_sip_supported,
    soa_base_remote_sip_features,
    soa_static_set_capability_sdp,
    soa_static_set_remote_sdp,
    soa_static_set_user_sdp,
    soa_static_generate_offer,
    soa_static_generate_answer,
    soa_static_process_answer,
    soa_static_process_reject,
    soa_static_activate,
    soa_static_deactivate,
    soa_static_terminate
  };

/* Initialize session */
static int soa_static_init(char const *name,
			   soa_session_t *ss,
			   soa_session_t *parent)
{
  return soa_base_init(name, ss, parent);
}

static void soa_static_deinit(soa_session_t *ss)
{
  soa_base_deinit(ss);
}

static int soa_static_set_params(soa_session_t *ss, tagi_t const *tags)
{
  soa_static_session_t *sss = (soa_static_session_t *)ss;
  char const *audio_aux = sss->sss_audio_aux;
  int ordered_user = sss->sss_ordered_user;
  int reuse_rejected = sss->sss_reuse_rejected;
  int n, m;

  n = tl_gets(tags,
	      SOATAG_AUDIO_AUX_REF(audio_aux),
	      SOATAG_ORDERED_USER_REF(ordered_user),
	      SOATAG_REUSE_REJECTED_REF(reuse_rejected),
	      TAG_END());

  if (n > 0 && str0casecmp(audio_aux, sss->sss_audio_aux)) {
    char *s = su_strdup(ss->ss_home, audio_aux), *tbf = sss->sss_audio_aux;
    if (s == NULL && audio_aux != NULL)
      return -1;
    sss->sss_audio_aux = s;
    if (tbf)
      su_free(ss->ss_home, tbf);
  }

  sss->sss_ordered_user = ordered_user != 0;
  sss->sss_reuse_rejected = reuse_rejected != 0;

  m = soa_base_set_params(ss, tags);
  if (m < 0)
    return m;

  return n + m;
}

static int soa_static_get_params(soa_session_t const *ss, tagi_t *tags)
{
  soa_static_session_t *sss = (soa_static_session_t *)ss;

  int n, m;

  n = tl_tgets(tags,
	       SOATAG_AUDIO_AUX(sss->sss_audio_aux),
	       SOATAG_ORDERED_USER(sss->sss_ordered_user),
	       SOATAG_REUSE_REJECTED(sss->sss_reuse_rejected),
	       TAG_END());
  m = soa_base_get_params(ss, tags);
  if (m < 0)
    return m;

  return n + m;
}

static tagi_t *soa_static_get_paramlist(soa_session_t const *ss,
					tag_type_t tag, tag_value_t value, 
					...)
{
  soa_static_session_t *sss = (soa_static_session_t *)ss;

  ta_list ta;
  tagi_t *tl;

  ta_start(ta, tag, value);

  tl = soa_base_get_paramlist(ss,
			      TAG_IF(sss->sss_audio_aux,
				     SOATAG_AUDIO_AUX(sss->sss_audio_aux)),
			      TAG_IF(sss->sss_ordered_user,
				     SOATAG_ORDERED_USER(1)),
			      TAG_IF(sss->sss_reuse_rejected,
				     SOATAG_REUSE_REJECTED(1)),
			      TAG_NEXT(ta_args(ta)));

  ta_end(ta);

  return tl;
}

static int soa_static_set_capability_sdp(soa_session_t *ss, 
					 sdp_session_t *sdp,
					 char const *sdp_str, 
					 isize_t sdp_len)
{
  return soa_base_set_capability_sdp(ss, sdp, sdp_str, sdp_len);
}


static int soa_static_set_remote_sdp(soa_session_t *ss, 
				     int new_version,
				     sdp_session_t *sdp,
				     char const *sdp_str, 
				     isize_t sdp_len)
{
  return soa_base_set_remote_sdp(ss, new_version, sdp, sdp_str, sdp_len);
}


static int soa_static_set_user_sdp(soa_session_t *ss, 
				   sdp_session_t *sdp,
				   char const *sdp_str, 
				   isize_t sdp_len)
{
  return soa_base_set_user_sdp(ss, sdp, sdp_str, sdp_len);
}

/** Generate a rejected m= line */
static
sdp_media_t *soa_sdp_make_rejected_media(su_home_t *home, 
					 sdp_media_t const *m,
					 sdp_session_t *sdp,
					 int include_all_codecs)
{
  sdp_media_t rejected[1] = {{ sizeof (rejected) }};

  rejected->m_type = m->m_type;
  rejected->m_type_name = m->m_type_name;
  rejected->m_port = 0;
  rejected->m_proto = m->m_proto;
  rejected->m_proto_name = m->m_proto_name;

  if (include_all_codecs) {
    rejected->m_rtpmaps = m->m_rtpmaps;
  }

  rejected->m_rejected = 1;

  return sdp_media_dup(home, rejected, sdp);
}

/** Expand a @a truncated SDP.
 */
static
sdp_session_t *soa_sdp_expand_media(su_home_t *home,
				    sdp_session_t const *truncated,
				    sdp_session_t const *complete)
{
  sdp_session_t *expanded;
  sdp_media_t **m0;
  sdp_media_t * const *m1;

  expanded = sdp_session_dup(home, truncated);

  if (expanded) {
    for (m0 = &expanded->sdp_media, m1 = &complete->sdp_media;
	 *m1;
	 m1 = &(*m1)->m_next) {
      if (!*m0) {
	*m0 = soa_sdp_make_rejected_media(home, *m1, expanded, 0);
	if (!*m0)
	  return NULL;
      }
      m0 = &(*m0)->m_next;
    }
  }

  return expanded;
}

/** Check if @a session should be upgraded with @a remote */ 
int soa_sdp_upgrade_is_needed(sdp_session_t const *session,
			      sdp_session_t const *remote)
{
  sdp_media_t const *rm, *lm;

  if (!remote)
    return 0;
  if (!session)
    return 1;

  for (rm = remote->sdp_media, lm = session->sdp_media; 
       rm && lm ; rm = rm->m_next, lm = lm->m_next) {
    if (rm->m_rejected)
      continue;
    if (lm->m_rejected)
      break;
  }

  return rm != NULL;
}

/** Check if codec is in auxiliary list */
static
int soa_sdp_is_auxiliary_codec(sdp_rtpmap_t const *rm, char const *auxiliary)
{
  char const *codec;
  size_t clen, alen;
  char const *match;

  if (!rm || !rm->rm_encoding || !auxiliary)
    return 0;

  codec = rm->rm_encoding;

  clen = strlen(codec), alen = strlen(auxiliary);

  if (clen > alen)
    return 0;

  for (match = auxiliary;
       (match = strcasestr(match, codec));
       match = match + 1) {
    if (IS_ALPHANUM(match[clen]) || match[clen] == '-')
      continue;
    if (match != auxiliary &&
	(IS_ALPHANUM(match[-1]) || match[-1] == '-'))
      continue;
    return 1;
  }

  return 0;
}

static
sdp_rtpmap_t *soa_sdp_media_matching_rtpmap(sdp_rtpmap_t const *from,
					    sdp_rtpmap_t const *anylist,
					    char const *auxiliary)
{
  sdp_rtpmap_t const *rm;

  for (rm = anylist; rm; rm = rm->rm_next) {
    /* Ignore auxiliary codecs */
    if (auxiliary && soa_sdp_is_auxiliary_codec(rm, auxiliary))
      continue;

    if (sdp_rtpmap_find_matching(from, rm))
      return (sdp_rtpmap_t *)rm;
  }

  return NULL;
}

#define SDP_MEDIA_NONE ((sdp_media_t *)-1)

/** Find first matching media in table @a mm.
 *
 * - if allow_rtp_mismatch == 0, search for a matching codec 
 * - if allow_rtp_mismatch == 1, prefer m=line with matching codec
 * - if allow_rtp_mismatch > 1, ignore codecs
 */
static
int soa_sdp_matching_mindex(soa_session_t *ss, 
			    sdp_media_t *mm[],
			    sdp_media_t const *with,
			    int *return_codec_mismatch)
{
  int i, j = -1;
  soa_static_session_t *sss = (soa_static_session_t *)ss;
  int rtp = sdp_media_uses_rtp(with), dummy;
  char const *auxiliary = NULL;

  if (return_codec_mismatch == NULL)
    return_codec_mismatch = &dummy;

  if (with->m_type == sdp_media_audio) {
    auxiliary = sss->sss_audio_aux;
    /* Looking for a single codec */
    if (with->m_rtpmaps && with->m_rtpmaps->rm_next == NULL)
      auxiliary = NULL;
  }

  for (i = 0; mm[i]; i++) {
    if (mm[i] == SDP_MEDIA_NONE)
      continue;

    if (!sdp_media_match_with(mm[i], with))
      continue;
    
    if (!rtp)
      break;

    if (soa_sdp_media_matching_rtpmap(with->m_rtpmaps, 
				      mm[i]->m_rtpmaps,
				      auxiliary))
      break;

    if (j == -1)
      j = i;
  }

  if (mm[i])
    return *return_codec_mismatch = 0, i;
  else
    return *return_codec_mismatch = 1, j;
}

/** Set payload types in @a l_m according to the values in @a r_m.
 * 
 * @retval number of common codecs
 */
static
int soa_sdp_set_rtpmap_pt(sdp_media_t *l_m, 
			  sdp_media_t const *r_m)
{
  sdp_rtpmap_t *lrm, **next_lrm;
  sdp_rtpmap_t const *rrm;

  int local_codecs = 0, common_codecs = 0;

  unsigned char dynamic_pt[128];
  unsigned pt;

  for (next_lrm = &l_m->m_rtpmaps; (lrm = *next_lrm); ) {
    if (lrm->rm_any) {
      /* Remove codecs known only by pt number */
      *next_lrm = lrm->rm_next;
      continue;
    }
    else {
      next_lrm = &lrm->rm_next;
    }

    local_codecs++;

    rrm = sdp_rtpmap_find_matching(r_m->m_rtpmaps, lrm);

    /* XXX - do fmtp comparison */

    if (rrm) {
      /* Use same payload type as remote */
      if (lrm->rm_pt != rrm->rm_pt) {
	lrm->rm_predef = 0;
	lrm->rm_pt = rrm->rm_pt;
      }
      common_codecs++;
    }
    else {
      /* Determine payload type later */
      lrm->rm_any = 1;
    }
  }
  
  if (local_codecs == common_codecs)