usrloc: detect lost tcp connnections on timer and set associated contact as expired

- new module parameter to control this feature: handle_lost_tcp
- at this moment it is not implemented for db only mode

modules/usrloc/ucontact.c

@@ -135,6 +135,7 @@ ucontact_t* new_ucontact(str* _dom, str* _aor, str* _contact, ucontact_info_t* _
 	c->reg_id = _ci->reg_id;
 	c->last_modified = _ci->last_modified;
 	c->last_keepalive = _ci->last_modified;
+	c->tcpconn_id = _ci->tcpconn_id;
 #ifdef WITH_XAVP
 	ucontact_xavp_store(c);
 #endif

modules/usrloc/ul_mod.c

@@ -161,6 +161,7 @@ int timer_interval  = 60;				/*!< Timer interval in seconds */
 int db_mode         = 0;				/*!< Database sync scheme: 0-no db, 1-write through, 2-write back, 3-only db */
 int use_domain      = 0;				/*!< Whether usrloc should use domain part of aor */
 int desc_time_order = 0;				/*!< By default do not enable timestamp ordering */
+int handle_lost_tcp = 0;
 
 int ul_fetch_rows = 2000;				/*!< number of rows to fetch from result */
 int ul_hash_size = 9;
@@ -214,6 +215,7 @@ static param_export_t params[] = {
 	{"fetch_rows",          INT_PARAM, &ul_fetch_rows   },
 	{"hash_size",           INT_PARAM, &ul_hash_size    },
 	{"nat_bflag",           INT_PARAM, &nat_bflag       },
+	{"handle_lost_tcp",     INT_PARAM, &handle_lost_tcp },
 	{"preload",             STR_PARAM|USE_FUNC_PARAM, (void*)ul_preload_param},
 	{"db_update_as_insert", INT_PARAM, &ul_db_update_as_insert},
 	{"timer_procs",         INT_PARAM, &ul_timer_procs},
@@ -387,6 +389,10 @@ static int mod_init(void)
 			return -1;
 		}
 	}
+
+	if (handle_lost_tcp && db_mode == DB_ONLY)
+		LM_WARN("handle_lost_tcp option makes nothing in DB_ONLY mode\n");
+
 	init_flag = 1;
 
 	return 0;

modules/usrloc/ul_mod.h

@@ -84,6 +84,7 @@ extern int ul_hash_size;
 extern int ul_db_update_as_insert;
 extern int ul_db_check_update;
 extern int ul_keepalive_timeout;
+extern int handle_lost_tcp;
 
 /*! nat branch flag */
 extern unsigned int nat_bflag;

modules/usrloc/urecord.c

@@ -40,6 +40,7 @@
 #include "../../dprint.h"
 #include "../../ut.h"
 #include "../../hashes.h"
+#include "../../tcp_conn.h"
 #include "ul_mod.h"
 #include "usrloc.h"
 #include "utime.h"
@@ -221,6 +222,26 @@ void mem_delete_ucontact(urecord_t* _r, ucontact_t* _c)
 	free_ucontact(_c);
 }
 
+static inline int is_valid_tcpconn(ucontact_t *c)
+{
+	if (c->tcpconn_id == -1)
+		return 0; /* tcpconn_id is not present */
+	else
+		return 1; /* valid tcpconn_id */
+}
+
+static inline int is_tcp_alive(ucontact_t *c)
+{
+	struct tcp_connection *con = NULL;
+	int rc = 0;
+
+	if ((con = tcpconn_get(c->tcpconn_id, 0, 0, 0, 0))) {
+		tcpconn_put(con); /* refcnt-- */
+		rc = 1;
+	}
+
+	return rc;
+}
 
 /*!
  * \brief Expires timer for NO_DB db_mode
@@ -236,6 +257,11 @@ static inline void nodb_timer(urecord_t* _r)
 	ptr = _r->contacts;
 
 	while(ptr) {
+		if (handle_lost_tcp && is_valid_tcpconn(ptr) && !is_tcp_alive(ptr)) {
+			LM_DBG("tcp connection has been lost, expiring contact %.*s\n", ptr->c.len, ptr->c.s);
+			ptr->expires = UL_EXPIRED_TIME;
+		}
+
 		if (!VALID_CONTACT(ptr, act_time)) {
 			/* run callbacks for EXPIRE event */
 			if (exists_ulcb_type(UL_CONTACT_EXPIRE))
@@ -296,7 +322,6 @@ static inline void wt_timer(urecord_t* _r)
 	}
 }
 
-
 /*!
  * \brief Write-back timer, used for WRITE_BACK db_mode
  *
@@ -316,6 +341,11 @@ static inline void wb_timer(urecord_t* _r)
 	ptr = _r->contacts;
 
 	while(ptr) {
+		if (handle_lost_tcp && is_valid_tcpconn(ptr) && !is_tcp_alive(ptr)) {
+			LM_DBG("tcp connection has been lost, expiring contact %.*s\n", ptr->c.len, ptr->c.s);
+			ptr->expires = UL_EXPIRED_TIME;
+		}
+
 		if (!VALID_CONTACT(ptr, act_time)) {
 			/* run callbacks for EXPIRE event */
 			if (exists_ulcb_type(UL_CONTACT_EXPIRE)) {

modules/usrloc/usrloc.h

@@ -91,6 +91,7 @@ typedef struct ucontact {
 	unsigned int methods;   /*!< Supported methods */
 	str instance;           /*!< SIP instance value - gruu */
 	unsigned int reg_id;    /*!< reg-id parameters */
+	int tcpconn_id;          /* unique tcp connection id */
 #ifdef WITH_XAVP
 	sr_xavp_t * xavp;       /*!< per contact xavps */
 #endif
@@ -116,6 +117,7 @@ typedef struct ucontact_info {
 	unsigned int methods;     /*!< supported methods */
 	str instance;             /*!< SIP instance value - gruu */
 	unsigned int reg_id;      /*!< reg-id parameters */
+	int tcpconn_id;
 #ifdef WITH_XAVP
 	sr_xavp_t * xavp;         /*!< per contact xavps */
 #endif