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authorPatrick McHardy <kaber@trash.net>2008-03-25 20:26:43 -0700
committerDavid S. Miller <davem@davemloft.net>2008-03-25 20:26:43 -0700
commitc7f485abd618e0d249bdd1abdc586bd10fee1954 (patch)
tree618ad078a96c0f7c641efaa38f0d363ee2775e42 /net/netfilter
parent0d0ab0378d67517a4f4ae3497706c13d9dd24af1 (diff)
[NETFILTER]: nf_conntrack_sip: RTP routing optimization
Optimize call routing between NATed endpoints: when an external registrar sends a media description that contains an existing RTP expectation from a different SNATed connection, the gatekeeper is trying to route the call directly between the two endpoints. We assume both endpoints can reach each other directly and "un-NAT" the addresses, which makes the media stream go between the two endpoints directly. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/nf_conntrack_sip.c59
1 files changed, 49 insertions, 10 deletions
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index f40a525732d1..57de22c770a3 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -70,6 +70,14 @@ unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb,
__read_mostly;
EXPORT_SYMBOL_GPL(nf_nat_sdp_addr_hook);
+unsigned int (*nf_nat_sdp_port_hook)(struct sk_buff *skb,
+ const char **dptr,
+ unsigned int *datalen,
+ unsigned int matchoff,
+ unsigned int matchlen,
+ u_int16_t port) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_port_hook);
+
unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb,
const char **dptr,
unsigned int dataoff,
@@ -730,9 +738,10 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
union nf_inet_addr *saddr;
struct nf_conntrack_tuple tuple;
int family = ct->tuplehash[!dir].tuple.src.l3num;
- int skip_expect = 0, ret = NF_DROP;
+ int direct_rtp = 0, skip_expect = 0, ret = NF_DROP;
u_int16_t base_port;
__be16 rtp_port, rtcp_port;
+ typeof(nf_nat_sdp_port_hook) nf_nat_sdp_port;
typeof(nf_nat_sdp_media_hook) nf_nat_sdp_media;
saddr = NULL;
@@ -746,6 +755,14 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
* to register it since we can see the same media description multiple
* times on different connections in case multiple endpoints receive
* the same call.
+ *
+ * RTP optimization: if we find a matching media channel expectation
+ * and both the expectation and this connection are SNATed, we assume
+ * both sides can reach each other directly and use the final
+ * destination address from the expectation. We still need to keep
+ * the NATed expectations for media that might arrive from the
+ * outside, and additionally need to expect the direct RTP stream
+ * in case it passes through us even without NAT.
*/
memset(&tuple, 0, sizeof(tuple));
if (saddr)
@@ -756,20 +773,42 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
tuple.dst.u.udp.port = port;
rcu_read_lock();
- exp = __nf_ct_expect_find(&tuple);
- if (exp && exp->master != ct &&
- nfct_help(exp->master)->helper == nfct_help(ct)->helper &&
- exp->class == class)
- skip_expect = 1;
- rcu_read_unlock();
+ do {
+ exp = __nf_ct_expect_find(&tuple);
- if (skip_expect)
- return NF_ACCEPT;
+ if (!exp || exp->master == ct ||
+ nfct_help(exp->master)->helper != nfct_help(ct)->helper ||
+ exp->class != class)
+ break;
+
+ if (exp->tuple.src.l3num == AF_INET && !direct_rtp &&
+ (exp->saved_ip != exp->tuple.dst.u3.ip ||
+ exp->saved_proto.udp.port != exp->tuple.dst.u.udp.port) &&
+ ct->status & IPS_NAT_MASK) {
+ daddr->ip = exp->saved_ip;
+ tuple.dst.u3.ip = exp->saved_ip;
+ tuple.dst.u.udp.port = exp->saved_proto.udp.port;
+ direct_rtp = 1;
+ } else
+ skip_expect = 1;
+ } while (!skip_expect);
+ rcu_read_unlock();
base_port = ntohs(tuple.dst.u.udp.port) & ~1;
rtp_port = htons(base_port);
rtcp_port = htons(base_port + 1);
+ if (direct_rtp) {
+ nf_nat_sdp_port = rcu_dereference(nf_nat_sdp_port_hook);
+ if (nf_nat_sdp_port &&
+ !nf_nat_sdp_port(skb, dptr, datalen,
+ mediaoff, medialen, ntohs(rtp_port)))
+ goto err1;
+ }
+
+ if (skip_expect)
+ return NF_ACCEPT;
+
rtp_exp = nf_ct_expect_alloc(ct);
if (rtp_exp == NULL)
goto err1;
@@ -783,7 +822,7 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
IPPROTO_UDP, NULL, &rtcp_port);
nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook);
- if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK)
+ if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK && !direct_rtp)
ret = nf_nat_sdp_media(skb, dptr, datalen, rtp_exp, rtcp_exp,
mediaoff, medialen, daddr);
else {