channels/chan_iax2: Add a configuration parameter for call token expiration

This patch adds a new configuration parameter, 'calltokenexpiration', that
controls how long before an authentication call token is expired. The default
maintains the RFC specified 10 seconds. Setting it to a higher value may be
useful in lossy networks.

Review: https://reviewboard.asterisk.org/r/4588

ASTERISK-24939 #close
Reported by: Y Ateya
patches:
  ctoken_configuration.diff submitted by Y Ateya (License 6693)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@434563 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

@@ -46,6 +46,10 @@ chan_iax2
  * The iax.conf forcejitterbuffer option has been removed.  It is now always
    forced if you set iax.conf jitterbuffer=yes.  If you put a jitter buffer
    on a channel it will be on the channel.
+ * A new configuration parameters, 'calltokenexpiration', has been added that
+   controls the duration before a call token expires. Default duration is 10
+   seconds. Setting this to a higher value may help in lagged networks or those
+   experiencing high packet loss.
 
 chan_sip
 ------------------

channels/chan_iax2.c

@@ -918,7 +918,7 @@ static struct ast_taskprocessor *transmit_processor;
 
 static int randomcalltokendata;
 
-static const time_t MAX_CALLTOKEN_DELAY = 10;
+static time_t max_calltoken_delay = 10;
 
 /*!
  * This module will get much higher performance when doing a lot of
@@ -4934,7 +4934,7 @@ static int handle_call_token(struct ast_iax2_full_hdr *fh, struct iax_ies *ies,
 		if (strcmp(hash, rec_hash)) {
 			ast_log(LOG_WARNING, "Address %s failed CallToken hash inspection\n", ast_sockaddr_stringify(addr));
 			goto reject; /* received hash does not match ours, reject */
-		} else if ((t < rec_time) || ((t - rec_time) >= MAX_CALLTOKEN_DELAY)) {
+		} else if ((t < rec_time) || ((t - rec_time) >= max_calltoken_delay)) {
 			ast_log(LOG_WARNING, "Too much delay in IAX2 calltoken timestamp from address %s\n", ast_sockaddr_stringify(addr));
 			goto reject; /* too much delay, reject */
 		}
@@ -13734,6 +13734,14 @@ static int set_config(const char *config_file, int reload, int forced)
 			if (add_calltoken_ignore(v->value)) {
 				ast_log(LOG_WARNING, "Invalid calltokenoptional address range - '%s' line %d\n", v->value, v->lineno);
 			}
+		} else if (!strcasecmp(v->name, "calltokenexpiration")) {
+			int temp = -1;
+			sscanf(v->value, "%u", &temp);
+			if( temp <= 0 ){
+				ast_log(LOG_WARNING, "Invalid calltokenexpiration value %s. Should be integer greater than 0.\n", v->value);
+			} else {
+				max_calltoken_delay = temp;
+			}
 		}  else if (!strcasecmp(v->name, "subscribe_network_change_event")) {
 			if (ast_true(v->value)) {
 				subscribe_network_change = 1;

configs/samples/iax.conf.sample

@@ -431,6 +431,10 @@ autokill=yes
 ;
 ;requirecalltoken=no
 ;
+; Maximum time allowed for call token authentication handshaking. Default is 10 seconds.
+; Use higher values in lagged or high packet loss networks.
+;
+;calltokenexpiration=10
 
 ;
 ; These options are used to limit the amount of call numbers allocated to a