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authorDavid Ahern <dsahern@gmail.com>2019-04-06 01:30:34 +0200
committerDavid S. Miller <davem@davemloft.net>2019-04-09 00:22:41 +0200
commit5c9f7c1dfc2e0776551ef1ceb335187c6698d1ff (patch)
treee32182b2068ba4ec08eb046acf973a9738a84820 /include/net/route.h
parentneighbor: Add skip_cache argument to neigh_output (diff)
downloadlinux-5c9f7c1dfc2e0776551ef1ceb335187c6698d1ff.tar.xz
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ipv4: Add helpers for neigh lookup for nexthop
A common theme in the output path is looking up a neigh entry for a nexthop, either the gateway in an rtable or a fallback to the daddr in the skb: nexthop = (__force u32)rt_nexthop(rt, ip_hdr(skb)->daddr); neigh = __ipv4_neigh_lookup_noref(dev, nexthop); if (unlikely(!neigh)) neigh = __neigh_create(&arp_tbl, &nexthop, dev, false); To allow the nexthop to be an IPv6 address we need to consider the family of the nexthop and then call __ipv{4,6}_neigh_lookup_noref based on it. To make this simpler, add a ip_neigh_gw4 helper similar to ip_neigh_gw6 added in an earlier patch which handles: neigh = __ipv4_neigh_lookup_noref(dev, nexthop); if (unlikely(!neigh)) neigh = __neigh_create(&arp_tbl, &nexthop, dev, false); And then add a second one, ip_neigh_for_gw, that calls either ip_neigh_gw4 or ip_neigh_gw6 based on the address family of the gateway. Update the output paths in the VRF driver and core v4 code to use ip_neigh_for_gw simplifying the family based lookup and making both ready for a v6 nexthop. ipv4_neigh_lookup has a different need - the potential to resolve a passed in address in addition to any gateway in the rtable or skb. Since this is a one-off, add ip_neigh_gw4 and ip_neigh_gw6 diectly. The difference between __neigh_create used by the helpers and neigh_create called by ipv4_neigh_lookup is taking a refcount, so add rcu_read_lock_bh and bump the refcnt on the neigh entry. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/route.h')
-rw-r--r--include/net/route.h32
1 files changed, 32 insertions, 0 deletions
diff --git a/include/net/route.h b/include/net/route.h
index 5d28a2509b58..96f6c9ae33c2 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -29,6 +29,8 @@
#include <net/flow.h>
#include <net/inet_sock.h>
#include <net/ip_fib.h>
+#include <net/arp.h>
+#include <net/ndisc.h>
#include <linux/in_route.h>
#include <linux/rtnetlink.h>
#include <linux/rcupdate.h>
@@ -350,4 +352,34 @@ static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
return hoplimit;
}
+static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
+ __be32 daddr)
+{
+ struct neighbour *neigh;
+
+ neigh = __ipv4_neigh_lookup_noref(dev, daddr);
+ if (unlikely(!neigh))
+ neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
+
+ return neigh;
+}
+
+static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
+ struct sk_buff *skb,
+ bool *is_v6gw)
+{
+ struct net_device *dev = rt->dst.dev;
+ struct neighbour *neigh;
+
+ if (likely(rt->rt_gw_family == AF_INET)) {
+ neigh = ip_neigh_gw4(dev, rt->rt_gw4);
+ } else if (rt->rt_gw_family == AF_INET6) {
+ neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
+ *is_v6gw = true;
+ } else {
+ neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
+ }
+ return neigh;
+}
+
#endif /* _ROUTE_H */