void SessionExpiresHelper::process_request(pjsip_msg* req,
pj_pool_t* pool,
SAS::TrailId trail)
{
// Session expires is only allowed on INVITE and UPDATE methods.
pjsip_method* method = &req->line.req.method;
if ((pjsip_method_cmp(method, pjsip_get_invite_method()) != 0) &&
(pjsip_method_cmp(method, &METHOD_UPDATE) != 0))
{
return;
}
// Store if this is the initial transaction on a dialog, and if the UAC
// supports session timers. We need both of these when processing the
// response.
_initial_request = (PJSIP_MSG_TO_HDR(req)->tag.slen == 0);
_uac_supports_timer = timer_supported(req);
// Find the session-expires header (if present) and the minimum
// session-expires. Note that the latter has a default value.
pjsip_session_expires_hdr* se_hdr = (pjsip_session_expires_hdr*)
pjsip_msg_find_hdr_by_name(req, &STR_SESSION_EXPIRES, NULL);
pjsip_min_se_hdr* min_se_hdr = (pjsip_min_se_hdr*)
pjsip_msg_find_hdr_by_name(req, &STR_MIN_SE, NULL);
SessionInterval min_se = (min_se_hdr != NULL) ?
min_se_hdr->expires :
DEFAULT_MIN_SE;
if ((se_hdr != NULL) && (se_hdr->expires < _target_se))
{
// The request already has a session expires that is below our target. We
// don't need to change the value.
TRC_DEBUG("Session expires already set to %d", se_hdr->expires);
}
else
{
// No pre-existing session expires, or the current value is greater than
// our target. Set it to as close to our target as possible, but don't set
// it below the min-SE.
if (se_hdr == NULL)
{
se_hdr = pjsip_session_expires_hdr_create(pool);
pjsip_msg_add_hdr(req, (pjsip_hdr*)se_hdr);
}
se_hdr->expires = std::max(_target_se, min_se);
TRC_DEBUG("Set session expires to %d", se_hdr->expires);
}
// Make a note of the session expires (we may need it when processing the
// response)
_se_on_req = se_hdr->expires;
}
void* pjsip_session_expires_hdr_shallow_clone(pj_pool_t* pool, const void* o)
{
pjsip_session_expires_hdr* hdr = pjsip_session_expires_hdr_create(pool);
pjsip_session_expires_hdr* other = (pjsip_session_expires_hdr*)o;
hdr->expires = other->expires;
hdr->refresher = other->refresher;
pjsip_param_shallow_clone(pool, &hdr->other_param, &other->other_param);
return hdr;
}
pjsip_hdr* parse_hdr_session_expires(pjsip_parse_ctx* ctx)
{
pj_pool_t* pool = ctx->pool;
pj_scanner* scanner = ctx->scanner;
pjsip_session_expires_hdr* hdr = pjsip_session_expires_hdr_create(pool);
const pjsip_parser_const_t* pc = pjsip_parser_const();
// Parse the expiry number
pj_str_t int_str;
pj_scan_get(scanner, &pc->pjsip_DIGIT_SPEC, &int_str);
hdr->expires = pj_strtoul(&int_str);
pj_scan_skip_whitespace(scanner);
// Parse the rest of the params, looking for the refresher param
while (*scanner->curptr == ';')
{
// Consume the ';'.
pj_scan_get_char(scanner);
pj_scan_skip_whitespace(scanner);
// Parse the param.
pj_str_t name;
pj_str_t value;
pjsip_parse_param_imp(scanner, pool, &name, &value,
PJSIP_PARSE_REMOVE_QUOTE);
if (!pj_stricmp2(&name, "refresher"))
{
if (!pj_stricmp2(&value, "uac"))
{
hdr->refresher = SESSION_REFRESHER_UAC;
}
else if (!pj_stricmp2(&value, "uas"))
{
hdr->refresher = SESSION_REFRESHER_UAS;
}
else
{
PJ_THROW(PJSIP_SYN_ERR_EXCEPTION); // LCOV_EXCL_LINE
}
}
else
{
pjsip_param* param = PJ_POOL_ALLOC_T(pool, pjsip_param);
param->name = name;
param->value = value;
pj_list_insert_before(&hdr->other_param, param);
}
}
// We're done parsing this header.
pjsip_parse_end_hdr_imp(scanner);
return (pjsip_hdr*)hdr;
}
void SessionExpiresHelper::process_response(pjsip_msg* rsp,
pj_pool_t* pool,
SAS::TrailId trail)
{
// Session expires is only allowed on INVITE and UPDATE methods.
pjsip_method* method = &PJSIP_MSG_CSEQ_HDR(rsp)->method;
if ((pjsip_method_cmp(method, pjsip_get_invite_method()) != 0) &&
(pjsip_method_cmp(method, &METHOD_UPDATE) != 0))
{
return;
}
// We only need to process successful final responses.
if (!PJSIP_IS_STATUS_IN_CLASS(rsp->line.status.code, 200))
{
return;
}
pjsip_session_expires_hdr* se_hdr = (pjsip_session_expires_hdr*)
pjsip_msg_find_hdr_by_name(rsp, &STR_SESSION_EXPIRES, NULL);
if (se_hdr == NULL)
{
// There is no session-expires header. This means we are most downstream
// device that supports session timers, and in particular the UAS does not
// support them.
//
// If the UAC does not support session timers, there's nothing more we can
// do - session timers will not be used for this dialog.
//
// If the UAC *does* support session timers, re-add a session-expires header
// that instructs the UAC to be the refresher.
if (_uac_supports_timer)
{
se_hdr = pjsip_session_expires_hdr_create(pool);
pjsip_msg_add_hdr(rsp, (pjsip_hdr*)se_hdr);
se_hdr->expires = _se_on_req;
se_hdr->refresher = SESSION_REFRESHER_UAC;
// Also update (or add) the require header to force the UAC to do session
// refreshes.
pjsip_require_hdr* require_hdr = (pjsip_require_hdr*)
pjsip_msg_find_hdr(rsp, PJSIP_H_REQUIRE, NULL);
if (require_hdr == NULL)
{
require_hdr = (pjsip_require_hdr*)pjsip_require_hdr_create(pool);
pjsip_msg_add_hdr(rsp, (pjsip_hdr*)require_hdr);
}
pj_strdup(pool, &require_hdr->values[require_hdr->count], &STR_TIMER);
require_hdr->count++;
}
}
if (_initial_request)
{
if (se_hdr == NULL)
{
SAS::Event event(trail, SASEvent::SESS_TIMER_NO_UA_SUPPORT, 0);
SAS::report_event(event);
}
else if (se_hdr->expires > _target_se)
{
SAS::Event event(trail, SASEvent::SESS_TIMER_INTERVAL_TOO_LONG, 0);
event.add_static_param(_target_se);
event.add_static_param(se_hdr->expires);
SAS::report_event(event);
}
}
}
