Commit 3b336d6f authored by Matteo Croce's avatar Matteo Croce Committed by David S. Miller
Browse files

flow_dissector: skip the ICMP dissector for non ICMP packets 



FLOW_DISSECTOR_KEY_ICMP is checked for every packet, not only ICMP ones.
Even if the test overhead is probably negligible, move the
ICMP dissector code under the big 'switch(ip_proto)' so it gets called
only for ICMP packets.

Signed-off-by: default avatarMatteo Croce <mcroce@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 98298e6c

net/core/flow_dissector.c

+25 −9
Original line number Diff line number Diff line
@@ -234,6 +234,25 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 
}

EXPORT_SYMBOL(__skb_flow_get_ports);



/* If FLOW_DISSECTOR_KEY_ICMP is set, get the Type and Code from an ICMP packet

 * using skb_flow_get_be16().

 */

static void __skb_flow_dissect_icmp(const struct sk_buff *skb,

				    struct flow_dissector *flow_dissector,

				    void *target_container,

				    void *data, int thoff, int hlen)

{

	struct flow_dissector_key_icmp *key_icmp;



	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ICMP))

		return;



	key_icmp = skb_flow_dissector_target(flow_dissector,

					     FLOW_DISSECTOR_KEY_ICMP,

					     target_container);

	key_icmp->icmp = skb_flow_get_be16(skb, thoff, data, hlen);

}



void skb_flow_dissect_meta(const struct sk_buff *skb,

			   struct flow_dissector *flow_dissector,

			   void *target_container)
@@ -884,7 +903,6 @@ bool __skb_flow_dissect(const struct net *net, 
	struct flow_dissector_key_basic *key_basic;

	struct flow_dissector_key_addrs *key_addrs;

	struct flow_dissector_key_ports *key_ports;

	struct flow_dissector_key_icmp *key_icmp;

	struct flow_dissector_key_tags *key_tags;

	struct flow_dissector_key_vlan *key_vlan;

	struct bpf_prog *attached = NULL;
@@ -1329,6 +1347,12 @@ ip_proto_again: 
				       data, nhoff, hlen);

		break;



	case IPPROTO_ICMP:

	case IPPROTO_ICMPV6:

		__skb_flow_dissect_icmp(skb, flow_dissector, target_container,

					data, nhoff, hlen);

		break;



	default:

		break;

	}
@@ -1342,14 +1366,6 @@ ip_proto_again: 
							data, hlen);

	}



	if (dissector_uses_key(flow_dissector,

			       FLOW_DISSECTOR_KEY_ICMP)) {

		key_icmp = skb_flow_dissector_target(flow_dissector,

						     FLOW_DISSECTOR_KEY_ICMP,

						     target_container);

		key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);

	}



	/* Process result of IP proto processing */

	switch (fdret) {

	case FLOW_DISSECT_RET_PROTO_AGAIN:

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