flow disector: ARP support

Allow dissection of (R)ARP operation hardware and protocol addresses
for Ethernet hardware and IPv4 protocol addresses.

There are currently no users of FLOW_DISSECTOR_KEY_ARP.
A follow-up patch will allow FLOW_DISSECTOR_KEY_ARP to be used by the
flower classifier.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index d896a33e00d4d1b5a81b85dd5766b78d09647d78..ac9703018a3a63bd392aa37f31b1afdf54d69aa0 100644 (file)
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -88,6 +88,24 @@ struct flow_dissector_key_addrs {
        };
 };
 
+/**
+ * flow_dissector_key_arp:
+ *     @ports: Operation, source and target addresses for an ARP header
+ *              for Ethernet hardware addresses and IPv4 protocol addresses
+ *             sip: Sender IP address
+ *             tip: Target IP address
+ *             op:  Operation
+ *             sha: Sender hardware address
+ *             tpa: Target hardware address
+ */
+struct flow_dissector_key_arp {
+       __u32 sip;
+       __u32 tip;
+       __u8 op;
+       unsigned char sha[ETH_ALEN];
+       unsigned char tha[ETH_ALEN];
+};
+
 /**
  * flow_dissector_key_tp_ports:
  *     @ports: port numbers of Transport header
@@ -141,6 +159,7 @@ enum flow_dissector_key_id {
        FLOW_DISSECTOR_KEY_ICMP, /* struct flow_dissector_key_icmp */
        FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
        FLOW_DISSECTOR_KEY_TIPC_ADDRS, /* struct flow_dissector_key_tipc_addrs */
+       FLOW_DISSECTOR_KEY_ARP, /* struct flow_dissector_key_arp */
        FLOW_DISSECTOR_KEY_VLAN, /* struct flow_dissector_key_flow_vlan */
        FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_flow_tags */
        FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index fe4e1531976c3a36127b6ad4af33f24534af4c52..5b3800fe20f325f2443cde395957d415a17009dc 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -138,6 +138,7 @@ 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;
@@ -379,6 +380,62 @@ mpls:
 
                nhoff += FCOE_HEADER_LEN;
                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 - sizeof(_arp),
+                                              &_arp_eth);
+               if (!arp)
+                       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;
        }