ipv6: Pass fib6_result to ip6_mtu_from_fib6 and fib6_mtu

Change ip6_mtu_from_fib6 and fib6_mtu to take a fib6_result over a
fib6_info. Update both to use the fib6_nh from fib6_result.

Since the signature of ip6_mtu_from_fib6 is already changing, add const
to daddr and saddr.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_route.h

@@ -302,8 +302,9 @@ static inline unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
 	return mtu;
 }
 
-u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
-		      struct in6_addr *saddr);
+u32 ip6_mtu_from_fib6(const struct fib6_result *res,
+		      const struct in6_addr *daddr,
+		      const struct in6_addr *saddr);
 
 struct neighbour *ip6_neigh_lookup(const struct in6_addr *gw,
 				   struct net_device *dev, struct sk_buff *skb,

include/net/ipv6_stubs.h

@@ -38,8 +38,9 @@ struct ipv6_stub {
 	void (*fib6_select_path)(const struct net *net, struct fib6_result *res,
 				 struct flowi6 *fl6, int oif, bool oif_match,
 				 const struct sk_buff *skb, int strict);
-	u32 (*ip6_mtu_from_fib6)(struct fib6_info *f6i, struct in6_addr *daddr,
-				 struct in6_addr *saddr);
+	u32 (*ip6_mtu_from_fib6)(const struct fib6_result *res,
+				 const struct in6_addr *daddr,
+				 const struct in6_addr *saddr);
 
 	int (*fib6_nh_init)(struct net *net, struct fib6_nh *fib6_nh,
 			    struct fib6_config *cfg, gfp_t gfp_flags,

net/core/filter.c

@@ -4761,7 +4761,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 				    fl6.flowi6_oif != 0, NULL, strict);
 
 	if (check_mtu) {
-		mtu = ipv6_stub->ip6_mtu_from_fib6(res.f6i, dst, src);
+		mtu = ipv6_stub->ip6_mtu_from_fib6(&res, dst, src);
 		if (params->tot_len > mtu)
 			return BPF_FIB_LKUP_RET_FRAG_NEEDED;
 	}

net/ipv6/addrconf_core.c

@@ -166,8 +166,9 @@ eafnosupport_fib6_select_path(const struct net *net, struct fib6_result *res,
 }
 
 static u32
-eafnosupport_ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
-			       struct in6_addr *saddr)
+eafnosupport_ip6_mtu_from_fib6(const struct fib6_result *res,
+			       const struct in6_addr *daddr,
+			       const struct in6_addr *saddr)
 {
 	return 0;
 }

net/ipv6/route.c

@@ -1417,14 +1417,15 @@ __rt6_find_exception_rcu(struct rt6_exception_bucket **bucket,
 	return NULL;
 }
 
-static unsigned int fib6_mtu(const struct fib6_info *rt)
+static unsigned int fib6_mtu(const struct fib6_result *res)
 {
+	const struct fib6_nh *nh = res->nh;
 	unsigned int mtu;
 
-	if (rt->fib6_pmtu) {
-		mtu = rt->fib6_pmtu;
+	if (res->f6i->fib6_pmtu) {
+		mtu = res->f6i->fib6_pmtu;
 	} else {
-		struct net_device *dev = fib6_info_nh_dev(rt);
+		struct net_device *dev = nh->fib_nh_dev;
 		struct inet6_dev *idev;
 
 		rcu_read_lock();
@@ -1435,7 +1436,7 @@ static unsigned int fib6_mtu(const struct fib6_info *rt)
 
 	mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
 
-	return mtu - lwtunnel_headroom(rt->fib6_nh.fib_nh_lws, mtu);
+	return mtu - lwtunnel_headroom(nh->fib_nh_lws, mtu);
 }
 
 static int rt6_insert_exception(struct rt6_info *nrt,
@@ -1481,7 +1482,7 @@ static int rt6_insert_exception(struct rt6_info *nrt,
 	 * Only insert this exception route if its mtu
 	 * is less than f6i's mtu value.
 	 */
-	if (dst_metric_raw(&nrt->dst, RTAX_MTU) >= fib6_mtu(res->f6i)) {
+	if (dst_metric_raw(&nrt->dst, RTAX_MTU) >= fib6_mtu(res)) {
 		err = -EINVAL;
 		goto out;
 	}
@@ -2640,12 +2641,15 @@ static unsigned int ip6_mtu(const struct dst_entry *dst)
  * based on ip6_dst_mtu_forward and exception logic of
  * rt6_find_cached_rt; called with rcu_read_lock
  */
-u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
-		      struct in6_addr *saddr)
+u32 ip6_mtu_from_fib6(const struct fib6_result *res,
+		      const struct in6_addr *daddr,
+		      const struct in6_addr *saddr)
 {
 	struct rt6_exception_bucket *bucket;
+	const struct fib6_nh *nh = res->nh;
+	struct fib6_info *f6i = res->f6i;
+	const struct in6_addr *src_key;
 	struct rt6_exception *rt6_ex;
-	struct in6_addr *src_key;
 	struct inet6_dev *idev;
 	u32 mtu = 0;
 
@@ -2667,7 +2671,7 @@ u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
 		mtu = dst_metric_raw(&rt6_ex->rt6i->dst, RTAX_MTU);
 
 	if (likely(!mtu)) {
-		struct net_device *dev = fib6_info_nh_dev(f6i);
+		struct net_device *dev = nh->fib_nh_dev;
 
 		mtu = IPV6_MIN_MTU;
 		idev = __in6_dev_get(dev);
@@ -2677,7 +2681,7 @@ u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
 
 	mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
 out:
-	return mtu - lwtunnel_headroom(fib6_info_nh_lwt(f6i), mtu);
+	return mtu - lwtunnel_headroom(nh->fib_nh_lws, mtu);
 }
 
 struct dst_entry *icmp6_dst_alloc(struct net_device *dev,