Merged revisions 312509 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r312509 | rmudgett | 2011-04-01 18:15:42 -0500 (Fri, 01 Apr 2011) | 22 lines
  
  When a call going out an NT-PTMP port gets rejected, Asterisk crashes.
  
  If a call is sent to an ISDN phone that rejects the call with
  RELEASE_COMPLETE(cause: call reject(21), or busy(17)) Asterisk crashes.
  
  I could not get my setup to crash.  However, I could see the possibility
  from a race condition between queuing an AST_CONTROL_BUSY to the core and
  then queueing an AST_CONTROL_HANGUP.  If the AST_CONTROL_BUSY is processed
  before the AST_CONTROL_HANGUP is queued, the ast_channel could be
  destroyed out from under chan_misdn.
  
  Avoid this particular crash scenario by not queueing the
  AST_CONTROL_HANGUP if the AST_CONTROL_BUSY was queued.
  
  (closes issue #18408)
  Reported by: wimpy
  Patches:
        issue18408_v1.8.patch uploaded by rmudgett (license 664)
  Tested by: rmudgett, wimpy
  
  JIRA SWP-2679
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@312510 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 22 insertions, 15 deletions

diff --git a/channels/chan_misdn.c b/channels/chan_misdn.c
index 194229723..d6e10aebe 100644
--- a/channels/chan_misdn.c
+++ b/channels/chan_misdn.c
@@ -681,7 +681,7 @@ static ast_mutex_t cl_te_lock;
 static enum event_response_e
 cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data);
 
-static void send_cause2ast(struct ast_channel *ast, struct misdn_bchannel*bc, struct chan_list *ch);
+static int send_cause2ast(struct ast_channel *ast, struct misdn_bchannel *bc, struct chan_list *ch);
 
 static void cl_queue_chan(struct chan_list *chan);
 
@@ -8364,8 +8364,7 @@ static void hangup_chan(struct chan_list *ch, struct misdn_bchannel *bc)
 		cb_log(2, port, " --> hangup\n");
 		ch->need_hangup = 0;
 		ch->need_queue_hangup = 0;
-		if (ch->ast) {
-			send_cause2ast(ch->ast, bc, ch);
+		if (ch->ast && send_cause2ast(ch->ast, bc, ch)) {
 			ast_hangup(ch->ast);
 		}
 		return;
@@ -8373,13 +8372,15 @@ static void hangup_chan(struct chan_list *ch, struct misdn_bchannel *bc)
 
 	if (!ch->need_queue_hangup) {
 		cb_log(2, port, " --> No need to queue hangup\n");
+		return;
 	}
 
 	ch->need_queue_hangup = 0;
 	if (ch->ast) {
-		send_cause2ast(ch->ast, bc, ch);
-		ast_queue_hangup_with_cause(ch->ast, bc->cause);
-		cb_log(2, port, " --> queue_hangup\n");
+		if (send_cause2ast(ch->ast, bc, ch)) {
+			ast_queue_hangup_with_cause(ch->ast, bc->cause);
+			cb_log(2, port, " --> queue_hangup\n");
+		}
 	} else {
 		cb_log(1, port, "Cannot hangup chan, no ast\n");
 	}
@@ -8653,26 +8654,31 @@ static void do_immediate_setup(struct misdn_bchannel *bc, struct chan_list *ch,
 	}
 }
 
+/*!
+ * \retval -1 if can hangup after calling.
+ * \retval 0 if cannot hangup after calling.
+ */
+static int send_cause2ast(struct ast_channel *ast, struct misdn_bchannel *bc, struct chan_list *ch)
+{
+	int can_hangup;
 
-
-static void send_cause2ast(struct ast_channel *ast, struct misdn_bchannel *bc, struct chan_list *ch) {
 	if (!ast) {
 		chan_misdn_log(1, 0, "send_cause2ast: No Ast\n");
-		return;
+		return 0;
 	}
 	if (!bc) {
 		chan_misdn_log(1, 0, "send_cause2ast: No BC\n");
-		return;
+		return 0;
 	}
 	if (!ch) {
 		chan_misdn_log(1, 0, "send_cause2ast: No Ch\n");
-		return;
+		return 0;
 	}
 
 	ast->hangupcause = bc->cause;
 
+	can_hangup = -1;
 	switch (bc->cause) {
-
 	case AST_CAUSE_UNALLOCATED:
 	case AST_CAUSE_NO_ROUTE_TRANSIT_NET:
 	case AST_CAUSE_NO_ROUTE_DESTINATION:
@@ -8699,15 +8705,16 @@ static void send_cause2ast(struct ast_channel *ast, struct misdn_bchannel *bc, s
 			chan_misdn_log(1, bc ? bc->port : 0, "Queued busy already\n");
 			break;
 		}
+		ch->need_busy = 0;
 
 		chan_misdn_log(1, bc ? bc->port : 0, " --> * SEND: Queue Busy pid:%d\n", bc ? bc->pid : -1);
-
 		ast_queue_control(ast, AST_CONTROL_BUSY);
 
-		ch->need_busy = 0;
-
+		/* The BUSY is likely to cause a hangup or the user needs to hear it. */
+		can_hangup = 0;
 		break;
 	}
+	return can_hangup;
 }