ice_session.c

一个开源的sip源代码

				      pj_str_t *data)
{
    pj_stun_session *sess = (pj_stun_session *)user_data;
    stun_data *sd = (stun_data*) pj_stun_session_get_user_data(sess);
    pj_ice_sess *ice = sd->ice;

    PJ_UNUSED_ARG(pool);
    realm->slen = nonce->slen = 0;

    if (PJ_STUN_IS_RESPONSE(msg->hdr.type)) {
	/* Outgoing responses need to have the same credential as
	 * incoming requests.
	 */
	*username = ice->rx_uname;
	*data_type = 0;
	*data = ice->rx_pass;
    }
    else {
	*username = ice->tx_uname;
	*data_type = 0;
	*data = ice->tx_pass;
    }

    return PJ_SUCCESS;
}

/* Get password to be used to authenticate incoming message */
static pj_status_t stun_auth_get_password(const pj_stun_msg *msg,
					  void *user_data, 
					  const pj_str_t *realm,
					  const pj_str_t *username,
					  pj_pool_t *pool,
					  int *data_type,
					  pj_str_t *data)
{
    pj_stun_session *sess = (pj_stun_session *)user_data;
    stun_data *sd = (stun_data*) pj_stun_session_get_user_data(sess);
    pj_ice_sess *ice = sd->ice;

    PJ_UNUSED_ARG(realm);
    PJ_UNUSED_ARG(pool);

    if (PJ_STUN_IS_SUCCESS_RESPONSE(msg->hdr.type) ||
	PJ_STUN_IS_ERROR_RESPONSE(msg->hdr.type))
    {
	/* Incoming response is authenticated with TX credential */
	/* Verify username */
	if (pj_strcmp(username, &ice->tx_uname) != 0)
	    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNKNOWN_USERNAME);
	*data_type = 0;
	*data = ice->tx_pass;

    } else {
	/* Incoming request is authenticated with RX credential */
	/* The agent MUST accept a credential if the username consists
	 * of two values separated by a colon, where the first value is
	 * equal to the username fragment generated by the agent in an offer
	 * or answer for a session in-progress, and the MESSAGE-INTEGRITY 
	 * is the output of a hash of the password and the STUN packet's 
	 * contents.
	 */
	const char *pos;
	pj_str_t ufrag;

	pos = (const char*)pj_memchr(username->ptr, ':', username->slen);
	if (pos == NULL)
	    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNKNOWN_USERNAME);

	ufrag.ptr = (char*)username->ptr;
	ufrag.slen = (pos - username->ptr);

	if (pj_strcmp(&ufrag, &ice->rx_ufrag) != 0)
	    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNKNOWN_USERNAME);

	*data_type = 0;
	*data = ice->rx_pass;

    }

    return PJ_SUCCESS;
}


static pj_uint32_t CALC_CAND_PRIO(pj_ice_sess *ice,
				  pj_ice_cand_type type,
				  pj_uint32_t local_pref,
				  pj_uint32_t comp_id)
{
    return ((ice->prefs[type] & 0xFF) << 24) + 
	   ((local_pref & 0xFFFF)    << 8) +
	   (((256 - comp_id) & 0xFF) << 0);
}


/*
 * Add ICE candidate
 */
PJ_DEF(pj_status_t) pj_ice_sess_add_cand(pj_ice_sess *ice,
					 unsigned comp_id,
					 pj_ice_cand_type type,
					 pj_uint16_t local_pref,
					 const pj_str_t *foundation,
					 const pj_sockaddr_t *addr,
					 const pj_sockaddr_t *base_addr,
					 const pj_sockaddr_t *rel_addr,
					 int addr_len,
					 unsigned *p_cand_id)
{
    pj_ice_sess_cand *lcand;
    pj_status_t status = PJ_SUCCESS;
    char tmp[128];

    PJ_ASSERT_RETURN(ice && comp_id && 
		     foundation && addr && base_addr && addr_len,
		     PJ_EINVAL);
    PJ_ASSERT_RETURN(comp_id <= ice->comp_cnt, PJ_EINVAL);

    pj_mutex_lock(ice->mutex);

    if (ice->lcand_cnt >= PJ_ARRAY_SIZE(ice->lcand)) {
	status = PJ_ETOOMANY;
	goto on_error;
    }

    lcand = &ice->lcand[ice->lcand_cnt];
    lcand->comp_id = comp_id;
    lcand->type = type;
    pj_strdup(ice->pool, &lcand->foundation, foundation);
    lcand->prio = CALC_CAND_PRIO(ice, type, local_pref, lcand->comp_id);
    pj_memcpy(&lcand->addr, addr, addr_len);
    pj_memcpy(&lcand->base_addr, base_addr, addr_len);
    if (rel_addr)
	pj_memcpy(&lcand->rel_addr, rel_addr, addr_len);
    else
	pj_bzero(&lcand->rel_addr, sizeof(lcand->rel_addr));


    pj_ansi_strcpy(tmp, pj_inet_ntoa(lcand->addr.ipv4.sin_addr));
    LOG4((ice->obj_name, 
	 "Candidate %d added: comp_id=%d, type=%s, foundation=%.*s, "
	 "addr=%s:%d, base=%s:%d, prio=0x%x (%u)",
	 ice->lcand_cnt, 
	 lcand->comp_id, 
	 cand_type_names[lcand->type],
	 (int)lcand->foundation.slen,
	 lcand->foundation.ptr,
	 tmp, 
	 (int)pj_ntohs(lcand->addr.ipv4.sin_port),
	 pj_inet_ntoa(lcand->base_addr.ipv4.sin_addr),
	 (int)pj_htons(lcand->base_addr.ipv4.sin_port),
	 lcand->prio, lcand->prio));

    if (p_cand_id)
	*p_cand_id = ice->lcand_cnt;

    ++ice->lcand_cnt;

on_error:
    pj_mutex_unlock(ice->mutex);
    return status;
}


/* Find default candidate ID for the component */
PJ_DEF(pj_status_t) pj_ice_sess_find_default_cand(pj_ice_sess *ice,
						  unsigned comp_id,
						  int *cand_id)
{
    unsigned i;

    PJ_ASSERT_RETURN(ice && comp_id && cand_id, PJ_EINVAL);
    PJ_ASSERT_RETURN(comp_id <= ice->comp_cnt, PJ_EINVAL);

    *cand_id = -1;

    pj_mutex_lock(ice->mutex);

    /* First find in valid list if we have nominated pair */
    for (i=0; i<ice->valid_list.count; ++i) {
	pj_ice_sess_check *check = &ice->valid_list.checks[i];
	
	if (check->lcand->comp_id == comp_id) {
	    *cand_id = GET_LCAND_ID(check->lcand);
	    pj_mutex_unlock(ice->mutex);
	    return PJ_SUCCESS;
	}
    }

    /* If there's no nominated pair, find relayed candidate */
    for (i=0; i<ice->lcand_cnt; ++i) {
	pj_ice_sess_cand *lcand = &ice->lcand[i];
	if (lcand->comp_id==comp_id &&
	    lcand->type == PJ_ICE_CAND_TYPE_RELAYED) 
	{
	    *cand_id = GET_LCAND_ID(lcand);
	    pj_mutex_unlock(ice->mutex);
	    return PJ_SUCCESS;
	}
    }

    /* If there's no relayed candidate, find reflexive candidate */
    for (i=0; i<ice->lcand_cnt; ++i) {
	pj_ice_sess_cand *lcand = &ice->lcand[i];
	if (lcand->comp_id==comp_id &&
	    (lcand->type == PJ_ICE_CAND_TYPE_SRFLX ||
	     lcand->type == PJ_ICE_CAND_TYPE_PRFLX)) 
	{
	    *cand_id = GET_LCAND_ID(lcand);
	    pj_mutex_unlock(ice->mutex);
	    return PJ_SUCCESS;
	}
    }

    /* Otherwise return host candidate */
    for (i=0; i<ice->lcand_cnt; ++i) {
	pj_ice_sess_cand *lcand = &ice->lcand[i];
	if (lcand->comp_id==comp_id &&
	    lcand->type == PJ_ICE_CAND_TYPE_HOST) 
	{
	    *cand_id = GET_LCAND_ID(lcand);
	    pj_mutex_unlock(ice->mutex);
	    return PJ_SUCCESS;
	}
    }

    /* Still no candidate is found! :( */
    pj_mutex_unlock(ice->mutex);

    pj_assert(!"Should have a candidate by now");
    return PJ_EBUG;
}


#ifndef MIN
#   define MIN(a,b) (a < b ? a : b)
#endif

#ifndef MAX
#   define MAX(a,b) (a > b ? a : b)
#endif

static pj_timestamp CALC_CHECK_PRIO(const pj_ice_sess *ice, 
				    const pj_ice_sess_cand *lcand,
				    const pj_ice_sess_cand *rcand)
{
    pj_uint32_t O, A;
    pj_timestamp prio;

    /* Original formula:
     *   pair priority = 2^32*MIN(O,A) + 2*MAX(O,A) + (O>A?1:0)
     */

    if (ice->role == PJ_ICE_SESS_ROLE_CONTROLLING) {
	O = lcand->prio; 
	A = rcand->prio;
    } else {
	O = rcand->prio;
	A = lcand->prio;
    }

    /*
    return ((pj_uint64_t)1 << 32) * MIN(O, A) +
	   (pj_uint64_t)2 * MAX(O, A) + (O>A ? 1 : 0);
    */

    prio.u32.hi = MIN(O,A);
    prio.u32.lo = (MAX(O, A) << 1) + (O>A ? 1 : 0);

    return prio;
}


PJ_INLINE(int) CMP_CHECK_PRIO(const pj_ice_sess_check *c1,
			      const pj_ice_sess_check *c2)
{
    return pj_cmp_timestamp(&c1->prio, &c2->prio);
}


#if PJ_LOG_MAX_LEVEL >= 4
static const char *dump_check(char *buffer, unsigned bufsize,
			      const pj_ice_sess_checklist *clist,
			      const pj_ice_sess_check *check)
{
    const pj_ice_sess_cand *lcand = check->lcand;
    const pj_ice_sess_cand *rcand = check->rcand;
    char laddr[CHECK_NAME_LEN];
    int len;

    pj_ansi_strcpy(laddr, pj_inet_ntoa(lcand->addr.ipv4.sin_addr));

    if (lcand->addr.addr.sa_family == PJ_AF_INET) {
	len = pj_ansi_snprintf(buffer, bufsize,
			       "%d: [%d] %s:%d-->%s:%d",
			       GET_CHECK_ID(clist, check),
			       check->lcand->comp_id,
			       laddr, (int)pj_ntohs(lcand->addr.ipv4.sin_port),
			       pj_inet_ntoa(rcand->addr.ipv4.sin_addr),
			       (int)pj_ntohs(rcand->addr.ipv4.sin_port));
    } else {
	len = pj_ansi_snprintf(buffer, bufsize, "IPv6->IPv6");
    }


    if (len < 0)
	len = 0;
    else if (len >= (int)bufsize)
	len = bufsize - 1;

    buffer[len] = '\0';
    return buffer;
}

static void dump_checklist(const char *title, const pj_ice_sess *ice, 
			   const pj_ice_sess_checklist *clist)
{
    unsigned i;
    char buffer[CHECK_NAME_LEN];

    LOG4((ice->obj_name, "%s", title));
    for (i=0; i<clist->count; ++i) {
	const pj_ice_sess_check *c = &clist->checks[i];
	LOG4((ice->obj_name, " %s (%s, state=%s)",
	     dump_check(buffer, sizeof(buffer), clist, c),
	     (c->nominated ? "nominated" : "not nominated"), 
	     check_state_name[c->state]));
    }
}

#else
#define dump_checklist(title, ice, clist)
#endif

static void check_set_state(pj_ice_sess *ice, pj_ice_sess_check *check,
			    pj_ice_sess_check_state st, 
			    pj_status_t err_code)
{
    char buf[CHECK_NAME_LEN];

    pj_assert(check->state < PJ_ICE_SESS_CHECK_STATE_SUCCEEDED);

    LOG5((ice->obj_name, "Check %s: state changed from %s to %s",
	 dump_check(buf, sizeof(buf), &ice->clist, check),
	 check_state_name[check->state],
	 check_state_name[st]));
    check->state = st;
    check->err_code = err_code;
}

static void clist_set_state(pj_ice_sess *ice, pj_ice_sess_checklist *clist,
			    pj_ice_sess_checklist_state st)
{
    if (clist->state != st) {
	LOG5((ice->obj_name, "Checklist: state changed from %s to %s",
	     clist_state_name[clist->state],
	     clist_state_name[st]));
	clist->state = st;
    }
}

/* Sort checklist based on priority */
static void sort_checklist(pj_ice_sess_checklist *clist)
{
    unsigned i;

    for (i=0; i<clist->count-1; ++i) {
	unsigned j, highest = i;
	for (j=i+1; j<clist->count; ++j) {
	    if (CMP_CHECK_PRIO(&clist->checks[j], &clist->checks[highest]) > 0) {
		highest = j;
	    }
	}

	if (highest != i) {
	    pj_ice_sess_check tmp;

	    pj_memcpy(&tmp, &clist->checks[i], sizeof(pj_ice_sess_check));
	    pj_memcpy(&clist->checks[i], &clist->checks[highest], 
		      sizeof(pj_ice_sess_check));
	    pj_memcpy(&clist->checks[highest], &tmp, 
		      sizeof(pj_ice_sess_check));
	}
    }
}

enum 
{ 
    SOCKADDR_EQUAL = 0, 
    SOCKADDR_NOT_EQUAL = 1 
};

/* Utility: compare sockaddr.
 * Returns 0 if equal.
 */
static int sockaddr_cmp(const pj_sockaddr *a1, const pj_sockaddr *a2)
{
    if (a1->addr.sa_family != a2->addr.sa_family)
	return SOCKADDR_NOT_EQUAL;

    if (a1->addr.sa_family == PJ_AF_INET) {
	return !(a1->ipv4.sin_addr.s_addr == a2->ipv4.sin_addr.s_addr &&
		 a1->ipv4.sin_port == a2->ipv4.sin_port);
    } else if (a1->addr.sa_family == PJ_AF_INET6) {
	return pj_memcmp(&a1->ipv6, &a2->ipv6, sizeof(a1->ipv6));
    } else {
	pj_assert(!"Invalid address family!");
	return SOCKADDR_NOT_EQUAL;
    }
}


/* Prune checklist, this must have been done after the checklist
 * is sorted.
 */
static pj_status_t prune_checklist(pj_ice_sess *ice, 
				   pj_ice_sess_checklist *clist)
{
    unsigned i;

    /* Since an agent cannot send requests directly from a reflexive
     * candidate, but only from its base, the agent next goes through the
     * sorted list of candidate pairs.  For each pair where the local
     * candidate is server reflexive, the server reflexive candidate MUST be
     * replaced by its base.  Once this has been done, the agent MUST prune
     * the list.  This is done by removing a pair if its local and remote
     * candidates are identical to the local and remote candidates of a pair
     * higher up on the priority list.  The result is a sequence of ordered
     * candidate pairs, called the check list for that media stream.    
     */
    /* First replace SRFLX candidates with their base */
    for (i=0; i<clist->count; ++i) {
	pj_ice_sess_cand *srflx = clist->checks[i].lcand;

	if (clist->checks[i].lcand->type == PJ_ICE_CAND_TYPE_SRFLX) {
	    /* Find the base for this candidate */
	    unsigned j;
	    for (j=0; j<ice->lcand_cnt; ++j) {