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Commit 43d2ccb3 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

flow_dissector: Fix fragment handling for header length computation 



It turns out that for IPv4 we were reporting the ip_proto of the fragment,
and for IPv6 we were not.  This patch updates that behavior so that we
always report the IP protocol of the fragment.  In addition it takes the
steps of updating the payload offset code so that we will determine the
start of the payload not including the L4 header for any fragment after the
first.

Signed-off-by: default avatarAlexander Duyck <aduyck@mirantis.com>
Acked-by: default avatarTom Herbert <tom@herbertland.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 918c023f

net/core/flow_dissector.c

+7 −3
Original line number Diff line number Diff line
@@ -448,14 +448,13 @@ bool __skb_flow_dissect(const struct sk_buff *skb, 
		key_control->flags |= FLOW_DIS_IS_FRAGMENT;



		nhoff += sizeof(_fh);

		ip_proto = fh->nexthdr;



		if (!(fh->frag_off & htons(IP6_OFFSET))) {

			key_control->flags |= FLOW_DIS_FIRST_FRAG;

			if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) {

				ip_proto = fh->nexthdr;

			if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)

				goto ip_proto_again;

		}

		}

		goto out_good;

	}

	case IPPROTO_IPIP:
@@ -741,6 +740,11 @@ u32 __skb_get_poff(const struct sk_buff *skb, void *data, 
{

	u32 poff = keys->control.thoff;



	/* skip L4 headers for fragments after the first */

	if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&

	    !(keys->control.flags & FLOW_DIS_FIRST_FRAG))

		return poff;



	switch (keys->basic.ip_proto) {

	case IPPROTO_TCP: {

		/* access doff as u8 to avoid unaligned access */