xfrm: respect ip protocols rules criteria when performing dst lookups

The series in the "fixes" tag added the ability to consider L4 attributes
in routing rules.

The dst lookup on the outer packet of encapsulated traffic in the xfrm
code was not adapted to this change, thus routing behavior that relies
on L4 information is not respected.

Pass the ip protocol information when performing dst lookups.

Fixes: a25724b ("Merge branch 'fib_rules-support-sport-dport-and-proto-match'")
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Tested-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Author: ebirger

include/net/xfrm.h

@@ -356,6 +356,8 @@ struct xfrm_dst_lookup_params {
 	xfrm_address_t *saddr;
 	xfrm_address_t *daddr;
 	u32 mark;
+	__u8 ipproto;
+	union flowi_uli uli;
 };
 
 struct net_device;

net/ipv4/xfrm4_policy.c

@@ -30,6 +30,8 @@ static struct dst_entry *__xfrm4_dst_lookup(struct flowi4 *fl4,
 	fl4->flowi4_mark = params->mark;
 	if (params->saddr)
 		fl4->saddr = params->saddr->a4;
+	fl4->flowi4_proto = params->ipproto;
+	fl4->uli = params->uli;
 
 	rt = __ip_route_output_key(params->net, fl4);
 	if (!IS_ERR(rt))

net/ipv6/xfrm6_policy.c

@@ -37,6 +37,9 @@ static struct dst_entry *xfrm6_dst_lookup(const struct xfrm_dst_lookup_params *p
 	if (params->saddr)
 		memcpy(&fl6.saddr, params->saddr, sizeof(fl6.saddr));
 
+	fl6.flowi4_proto = params->ipproto;
+	fl6.uli = params->uli;
+
 	dst = ip6_route_output(params->net, NULL, &fl6);
 
 	err = dst->error;

net/xfrm/xfrm_policy.c

@@ -315,6 +315,21 @@ static inline struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x,
 	params.tos = tos;
 	params.oif = oif;
 	params.mark = mark;
+	params.ipproto = x->id.proto;
+	if (x->encap) {
+		switch (x->encap->encap_type) {
+		case UDP_ENCAP_ESPINUDP:
+			params.ipproto = IPPROTO_UDP;
+			params.uli.ports.sport = x->encap->encap_sport;
+			params.uli.ports.dport = x->encap->encap_dport;
+			break;
+		case TCP_ENCAP_ESPINTCP:
+			params.ipproto = IPPROTO_TCP;
+			params.uli.ports.sport = x->encap->encap_sport;
+			params.uli.ports.dport = x->encap->encap_dport;
+			break;
+		}
+	}
 
 	dst = __xfrm_dst_lookup(family, &params);