[NETFILTER]: nf_conntrack_sip: flush expectations on call termination

Flush the RTP expectations we've created when a call is hung up or
terminated otherwise.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nf_conntrack_sip.c

@@ -17,6 +17,7 @@
 #include <linux/netfilter.h>
 
 #include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_conntrack_expect.h>
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <linux/netfilter/nf_conntrack_sip.h>
@@ -533,6 +534,22 @@ int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr,
 }
 EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header);
 
+static void flush_expectations(struct nf_conn *ct)
+{
+	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_conntrack_expect *exp;
+	struct hlist_node *n, *next;
+
+	spin_lock_bh(&nf_conntrack_lock);
+	hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
+		if (!del_timer(&exp->timeout))
+			continue;
+		nf_ct_unlink_expect(exp);
+		nf_ct_expect_put(exp);
+	}
+	spin_unlock_bh(&nf_conntrack_lock);
+}
+
 static int set_expected_rtp(struct sk_buff *skb,
 			    const char **dptr, unsigned int *datalen,
 			    union nf_inet_addr *addr, __be16 port)
@@ -606,32 +623,58 @@ static int process_invite_response(struct sk_buff *skb,
 				   const char **dptr, unsigned int *datalen,
 				   unsigned int cseq, unsigned int code)
 {
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+
 	if ((code >= 100 && code <= 199) ||
 	    (code >= 200 && code <= 299))
 		return process_sdp(skb, dptr, datalen, cseq);
-
-	return NF_ACCEPT;
+	else {
+		flush_expectations(ct);
+		return NF_ACCEPT;
+	}
 }
 
 static int process_update_response(struct sk_buff *skb,
 				   const char **dptr, unsigned int *datalen,
 				   unsigned int cseq, unsigned int code)
 {
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+
 	if ((code >= 100 && code <= 199) ||
 	    (code >= 200 && code <= 299))
 		return process_sdp(skb, dptr, datalen, cseq);
-
-	return NF_ACCEPT;
+	else {
+		flush_expectations(ct);
+		return NF_ACCEPT;
+	}
 }
 
 static int process_prack_response(struct sk_buff *skb,
 				  const char **dptr, unsigned int *datalen,
 				  unsigned int cseq, unsigned int code)
 {
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+
 	if ((code >= 100 && code <= 199) ||
 	    (code >= 200 && code <= 299))
 		return process_sdp(skb, dptr, datalen, cseq);
+	else {
+		flush_expectations(ct);
+		return NF_ACCEPT;
+	}
+}
+
+static int process_bye_request(struct sk_buff *skb,
+			       const char **dptr, unsigned int *datalen,
+			       unsigned int cseq)
+{
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 
+	flush_expectations(ct);
 	return NF_ACCEPT;
 }
 
@@ -640,6 +683,7 @@ static const struct sip_handler sip_handlers[] = {
 	SIP_HANDLER("UPDATE", process_sdp, process_update_response),
 	SIP_HANDLER("ACK", process_sdp, NULL),
 	SIP_HANDLER("PRACK", process_sdp, process_prack_response),
+	SIP_HANDLER("BYE", process_bye_request, NULL),
 };
 
 static int process_sip_response(struct sk_buff *skb,