From: Brett Bryant <bbryant@digium.com>
Date: Fri, 13 May 2011 18:04:50 +0000 (+0000)
Subject: This patch fixes an issue with SRTP which makes HOLD/UNHOLD impossible when too
X-Git-Tag: 1.8.5-rc1~11^2~117
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7f7f233e8f90527446f25fedc5c7732fb85e510c;p=thirdparty%2Fasterisk.git

This patch fixes an issue with SRTP which makes HOLD/UNHOLD impossible when too
much time has passed between sending audio.

(closes issue #18206)
Reported by: bernhardsi
Patches:
      res_srtp_unhold.patch uploaded by bernhards (license 1138)
Tested by: bernhards, notthematrix



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@318919 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---

diff --git a/res/res_srtp.c b/res/res_srtp.c
index f21ac0f996..3e9525afd5 100644
--- a/res/res_srtp.c
+++ b/res/res_srtp.c
@@ -314,8 +314,11 @@ static int ast_srtp_unprotect(struct ast_srtp *srtp, void *buf, int *len, int rt
 {
 	int res = 0;
 	int i;
+	int retry = 0;
 	struct ast_rtp_instance_stats stats = {0,};
 
+	tryagain:
+
 	for (i = 0; i < 2; i++) {
 		res = rtcp ? srtp_unprotect_rtcp(srtp->session, buf, len) : srtp_unprotect(srtp->session, buf, len);
 		if (res != err_status_no_ctx) {
@@ -334,6 +337,49 @@ static int ast_srtp_unprotect(struct ast_srtp *srtp, void *buf, int *len, int rt
 		}
 	}
 
+	if (retry == 0  && res == err_status_replay_old) {
+		ast_log(LOG_WARNING, "SRTP unprotect: %s\n", srtp_errstr(res));
+
+		if (srtp->session) {
+			struct ast_srtp_policy *policy;
+			struct ao2_iterator it;
+			int policies_count = 0;
+			
+			// dealloc first
+			ast_log(LOG_WARNING, "SRTP destroy before re-create\n");
+			srtp_dealloc(srtp->session);
+			
+			// get the count
+			policies_count = ao2_container_count(srtp->policies);
+			
+			// get the first to build up
+			it = ao2_iterator_init(srtp->policies, 0);
+			policy = ao2_iterator_next(&it);
+
+			ast_log(LOG_WARNING, "SRTP try to re-create\n");
+        		if (srtp_create(&srtp->session, &policy->sp) == err_status_ok) {
+				ast_log(LOG_WARNING, "SRTP re-created with first policy\n");
+				
+				// unref first element
+				ao2_t_ref(policy, -1, "Unreffing first policy for re-creating srtp session");
+				
+				// if we have more than one policy, add them afterwards	
+				if (policies_count > 1) {
+					ast_log(LOG_WARNING, "Add all the other %d policies\n", policies_count-1);
+					while ((policy = ao2_iterator_next(&it))) {
+						srtp_add_stream(srtp->session, &policy->sp);
+						ao2_t_ref(policy, -1, "Unreffing n-th policy for re-creating srtp session");
+					}
+				}
+				
+				retry++;
+				ao2_iterator_destroy(&it);
+				goto tryagain;
+			}
+			ao2_iterator_destroy(&it);
+		}
+	}
+
 	if (res != err_status_ok && res != err_status_replay_fail ) {
 		ast_log(LOG_WARNING, "SRTP unprotect: %s\n", srtp_errstr(res));
 		errno = EAGAIN;