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Commit 9bf881ff authored by Jiri Pirko's avatar Jiri Pirko Committed by David S. Miller
Browse files

flow_dissector: Move ARP dissection into a separate function 



Make the main flow_dissect function a bit smaller and move the ARP
dissection into a separate function. Along with that, do the ARP header
processing only in case the flow dissection user requires it.

Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fa383d66

net/core/flow_dissector.c

+67 −53
Original line number Diff line number Diff line
@@ -113,6 +113,66 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 
}

EXPORT_SYMBOL(__skb_flow_get_ports);



enum flow_dissect_ret {

	FLOW_DISSECT_RET_OUT_GOOD,

	FLOW_DISSECT_RET_OUT_BAD,

};



static enum flow_dissect_ret

__skb_flow_dissect_arp(const struct sk_buff *skb,

		       struct flow_dissector *flow_dissector,

		       void *target_container, void *data, int nhoff, int hlen)

{

	struct flow_dissector_key_arp *key_arp;

	struct {

		unsigned char ar_sha[ETH_ALEN];

		unsigned char ar_sip[4];

		unsigned char ar_tha[ETH_ALEN];

		unsigned char ar_tip[4];

	} *arp_eth, _arp_eth;

	const struct arphdr *arp;

	struct arphdr *_arp;



	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP))

		return FLOW_DISSECT_RET_OUT_GOOD;



	arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,

				   hlen, &_arp);

	if (!arp)

		return FLOW_DISSECT_RET_OUT_BAD;



	if (arp->ar_hrd != htons(ARPHRD_ETHER) ||

	    arp->ar_pro != htons(ETH_P_IP) ||

	    arp->ar_hln != ETH_ALEN ||

	    arp->ar_pln != 4 ||

	    (arp->ar_op != htons(ARPOP_REPLY) &&

	     arp->ar_op != htons(ARPOP_REQUEST)))

		return FLOW_DISSECT_RET_OUT_BAD;



	arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp),

				       sizeof(_arp_eth), data,

				       hlen, &_arp_eth);

	if (!arp_eth)

		return FLOW_DISSECT_RET_OUT_BAD;



	key_arp = skb_flow_dissector_target(flow_dissector,

					    FLOW_DISSECTOR_KEY_ARP,

					    target_container);



	memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip));

	memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip));



	/* Only store the lower byte of the opcode;

	 * this covers ARPOP_REPLY and ARPOP_REQUEST.

	 */

	key_arp->op = ntohs(arp->ar_op) & 0xff;



	ether_addr_copy(key_arp->sha, arp_eth->ar_sha);

	ether_addr_copy(key_arp->tha, arp_eth->ar_tha);



	return FLOW_DISSECT_RET_OUT_GOOD;

}



/**

 * __skb_flow_dissect - extract the flow_keys struct and return it

 * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
@@ -138,7 +198,6 @@ bool __skb_flow_dissect(const struct sk_buff *skb, 
	struct flow_dissector_key_control *key_control;

	struct flow_dissector_key_basic *key_basic;

	struct flow_dissector_key_addrs *key_addrs;

	struct flow_dissector_key_arp *key_arp;

	struct flow_dissector_key_ports *key_ports;

	struct flow_dissector_key_icmp *key_icmp;

	struct flow_dissector_key_tags *key_tags;
@@ -382,60 +441,15 @@ bool __skb_flow_dissect(const struct sk_buff *skb, 
		goto out_good;



	case htons(ETH_P_ARP):

	case htons(ETH_P_RARP): {

		struct {

			unsigned char ar_sha[ETH_ALEN];

			unsigned char ar_sip[4];

			unsigned char ar_tha[ETH_ALEN];

			unsigned char ar_tip[4];

		} *arp_eth, _arp_eth;

		const struct arphdr *arp;

		struct arphdr *_arp;



		arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,

					   hlen, &_arp);

		if (!arp)

			goto out_bad;



		if (arp->ar_hrd != htons(ARPHRD_ETHER) ||

		    arp->ar_pro != htons(ETH_P_IP) ||

		    arp->ar_hln != ETH_ALEN ||

		    arp->ar_pln != 4 ||

		    (arp->ar_op != htons(ARPOP_REPLY) &&

		     arp->ar_op != htons(ARPOP_REQUEST)))

			goto out_bad;



		arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp),

					       sizeof(_arp_eth), data,

					       hlen,

					       &_arp_eth);

		if (!arp_eth)

			goto out_bad;



		if (dissector_uses_key(flow_dissector,

				       FLOW_DISSECTOR_KEY_ARP)) {



			key_arp = skb_flow_dissector_target(flow_dissector,

							    FLOW_DISSECTOR_KEY_ARP,

							    target_container);



			memcpy(&key_arp->sip, arp_eth->ar_sip,

			       sizeof(key_arp->sip));

			memcpy(&key_arp->tip, arp_eth->ar_tip,

			       sizeof(key_arp->tip));



			/* Only store the lower byte of the opcode;

			 * this covers ARPOP_REPLY and ARPOP_REQUEST.

			 */

			key_arp->op = ntohs(arp->ar_op) & 0xff;



			ether_addr_copy(key_arp->sha, arp_eth->ar_sha);

			ether_addr_copy(key_arp->tha, arp_eth->ar_tha);

		}



	case htons(ETH_P_RARP):

		switch (__skb_flow_dissect_arp(skb, flow_dissector,

					       target_container, data,

					       nhoff, hlen)) {

		case FLOW_DISSECT_RET_OUT_GOOD:

			goto out_good;

		case FLOW_DISSECT_RET_OUT_BAD:

			goto out_bad;

		}



	default:

		goto out_bad;

	}