Subject: Re: [PATCH/RFC net-next 1/2] flow dissector: ND support

From: Jiri Pirko <[email-masked]>
Date: Fri, 10 Mar 2017 15:27:32 +0100

Fri, Mar 10, 2017 at 03:19:13PM CET, [email-masked] wrote:
>On Tue, Feb 21, 2017 at 04:28:10PM +0100, Jiri Pirko wrote:
>> Thu, Feb 02, 2017 at 11:37:34AM CET, [email-masked] wrote:
>> >Allow dissection of Neighbour Discovery target IP, and source and
>> >destination link-layer addresses for neighbour solicitation and
>> >advertisement messages.
>> >
>> >Signed-off-by: Simon Horman <[email-masked]>
>> >---
>> 
>> [...]
>> 
>> >@@ -633,6 +702,18 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
>> > 						     FLOW_DISSECTOR_KEY_ICMP,
>> > 						     target_container);
>> > 		key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);
>> >+
>> >+		if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ND) &&
>> >+		    ip_proto == IPPROTO_IPV6 && key_icmp->code == 0 &&
>> 
>> IPPROTO_IPV6 say "IPv6-in-IPv4 tunnelling". Please use "NEXTHDR_IPV6"
>> instead.
>
>Thanks, will do.
>
>> >+		    (key_icmp->type == NDISC_NEIGHBOUR_SOLICITATION ||
>> >+		     key_icmp->type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
>> >+			key_nd = skb_flow_dissector_target(flow_dissector,
>> >+							   FLOW_DISSECTOR_KEY_ND,
>> >+							   target_container);
>> >+			if (!(skb_flow_dissect_nd(skb, key_nd, data, nhoff,
>> >+						  hlen, ipv6_payload_len)))
>> >+				goto out_bad;
>> >+		}
>> 
>> You should put this under "switch (ip_proto) {"
>
>I see that makes sense in terms of the check against ip_proto.
>But I added it here to allow checking against key_icmp->code
>and key_icmp->type as well.

Sure. Just add under "switch (ip_proto) {" and call a wrapper nd
function from there. In that function, you check dissector_uses_key and
other needed things.