src: support for arp sender and target ethernet and IPv4 addresses

 # nft add table arp x
 # nft add chain arp x y { type filter hook input priority 0\; }
 # nft add rule arp x y arp saddr ip 192.168.2.1 counter

Testing this:

 # ip neigh flush dev eth0
 # ping 8.8.8.8
 # nft list ruleset
 table arp x {
        chain y {
                type filter hook input priority filter; policy accept;
                arp saddr ip 192.168.2.1 counter packets 1 bytes 46
        }
 }

You can also specify hardware sender address, eg.

 # nft add rule arp x y arp saddr ether aa:bb:cc:aa:bb:cc drop counter

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/tests/py/arp/arp.t.payload b/tests/py/arp/arp.t.payload
index 33e73417..d36bef18 100644
--- a/tests/py/arp/arp.t.payload
+++ b/tests/py/arp/arp.t.payload
@@ -280,3 +280,24 @@ arp test-arp input
   [ cmp eq reg 1 0x108fa8c0 ]
   [ immediate reg 1 0x44332211 0x00006655 ]
   [ payload write reg 1 => 6b @ network header + 18 csum_type 0 csum_off 0 csum_flags 0x0 ]
+
+# arp saddr ip 1.2.3.4
+arp test-arp input 
+  [ payload load 4b @ network header + 14 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# arp daddr ip 4.3.2.1
+arp test-arp input 
+  [ payload load 4b @ network header + 24 => reg 1 ]
+  [ cmp eq reg 1 0x01020304 ]
+
+# arp saddr ether aa:bb:cc:aa:bb:cc
+arp test-arp input 
+  [ payload load 6b @ network header + 8 => reg 1 ]
+  [ cmp eq reg 1 0xaaccbbaa 0x0000ccbb ]
+
+# arp daddr ether aa:bb:cc:aa:bb:cc
+arp test-arp input 
+  [ payload load 6b @ network header + 18 => reg 1 ]
+  [ cmp eq reg 1 0xaaccbbaa 0x0000ccbb ]
+