vxlan: fix populating tclass in vxlan6_get_route

borkmann · davem330 · commit eaa93bf4c609 · 2016-03-20T13:44:34.000-04:00
Jiri mentioned that flowi6_tos of struct flowi6 is never used/read anywhere. In fact, rest of the kernel uses the flowi6's flowlabel, where the traffic class _and_ the flowlabel (aka flowinfo) is encoded. For example, for policy routing, fib6_rule_match() uses ip6_tclass() that is applied on the flowlabel member for matching on tclass. Similar fix is needed for geneve, where flowi6_tos is set as well. Installing a v6 blackhole rule that f.e. matches on tos is now working with vxlan. Fixes: 1400615 ("vxlan: allow setting ipv6 traffic class") Reported-by: Jiri Benc <jbenc@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
@@ -1810,10 +1810,9 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
 
 	memset(&fl6, 0, sizeof(fl6));
 	fl6.flowi6_oif = oif;
-	fl6.flowi6_tos = RT_TOS(tos);
 	fl6.daddr = *daddr;
 	fl6.saddr = vxlan->cfg.saddr.sin6.sin6_addr;
-	fl6.flowlabel = label;
+	fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tos), label);
 	fl6.flowi6_mark = skb->mark;
 	fl6.flowi6_proto = IPPROTO_UDP;
 
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
@@ -835,6 +835,12 @@ static inline u8 ip6_tclass(__be32 flowinfo)
 {
 	return ntohl(flowinfo & IPV6_TCLASS_MASK) >> IPV6_TCLASS_SHIFT;
 }
+
+static inline __be32 ip6_make_flowinfo(unsigned int tclass, __be32 flowlabel)
+{
+	return htonl(tclass << IPV6_TCLASS_SHIFT) | flowlabel;
+}
+
 /*
  *	Prototypes exported by ipv6
  */

Original file line number	Diff line number	Diff line change
`@@ -835,6 +835,12 @@ static inline u8 ip6_tclass(__be32 flowinfo)`
`835`	`835`	`{`
`836`	`836`	`return ntohl(flowinfo & IPV6_TCLASS_MASK) >> IPV6_TCLASS_SHIFT;`
`837`	`837`	`}`
	`838`	`+`
	`839`	`+static inline __be32 ip6_make_flowinfo(unsigned int tclass, __be32 flowlabel)`
	`840`	`+{`
	`841`	`+ return htonl(tclass << IPV6_TCLASS_SHIFT) \| flowlabel;`
	`842`	`+}`
	`843`	`+`
`838`	`844`	`/*`
`839`	`845`	`* Prototypes exported by ipv6`
`840`	`846`	`*/`