From 9bf881ffc5c0e65343fb51eef10dd989b36d1c1f Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Mon, 6 Mar 2017 16:39:51 +0100 Subject: [PATCH] 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: Jiri Pirko Signed-off-by: David S. Miller --- net/core/flow_dissector.c | 120 +++++++++++++++++++++----------------- 1 file changed, 67 insertions(+), 53 deletions(-) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index c35aae13c8d2..d79fb8f8f033 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -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) + 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; - - 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); } - - goto out_good; - } - default: goto out_bad; }