net: ipv6: ip6mr: Split ip6mr_forward2() in two

Some of the work of ip6mr_forward2() is specific to IPMR forwarding, and
should not take place on the output path. In order to allow reuse of the
common parts, extract out of the function a helper,
ip6mr_prepare_forward().

Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://patch.msgid.link/8932bd5c0fbe3f662b158803b8509604fa7bc113.1750113335.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 41c348209e1b45edf90a3eda965bcfa1484be091..bd964564160d08724f8a4b669d83737cf92ee556 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2035,11 +2035,10 @@ static inline int ip6mr_forward2_finish(struct net *net, struct sock *sk, struct
  *     Processing handlers for ip6mr_forward
  */
 
-static void ip6mr_forward2(struct net *net, struct mr_table *mrt,
-                          struct sk_buff *skb, int vifi)
+static int ip6mr_prepare_xmit(struct net *net, struct mr_table *mrt,
+                             struct sk_buff *skb, int vifi)
 {
        struct vif_device *vif = &mrt->vif_table[vifi];
-       struct net_device *indev = skb->dev;
        struct net_device *vif_dev;
        struct ipv6hdr *ipv6h;
        struct dst_entry *dst;
@@ -2047,7 +2046,7 @@ static void ip6mr_forward2(struct net *net, struct mr_table *mrt,
 
        vif_dev = vif_dev_read(vif);
        if (!vif_dev)
-               goto out_free;
+               return -1;
 
 #ifdef CONFIG_IPV6_PIMSM_V2
        if (vif->flags & MIFF_REGISTER) {
@@ -2056,7 +2055,7 @@ static void ip6mr_forward2(struct net *net, struct mr_table *mrt,
                DEV_STATS_ADD(vif_dev, tx_bytes, skb->len);
                DEV_STATS_INC(vif_dev, tx_packets);
                ip6mr_cache_report(mrt, skb, vifi, MRT6MSG_WHOLEPKT);
-               goto out_free;
+               return -1;
        }
 #endif
 
@@ -2070,7 +2069,7 @@ static void ip6mr_forward2(struct net *net, struct mr_table *mrt,
        dst = ip6_route_output(net, NULL, &fl6);
        if (dst->error) {
                dst_release(dst);
-               goto out_free;
+               return -1;
        }
 
        skb_dst_drop(skb);
@@ -2094,10 +2093,20 @@ static void ip6mr_forward2(struct net *net, struct mr_table *mrt,
        /* We are about to write */
        /* XXX: extension headers? */
        if (skb_cow(skb, sizeof(*ipv6h) + LL_RESERVED_SPACE(vif_dev)))
-               goto out_free;
+               return -1;
 
        ipv6h = ipv6_hdr(skb);
        ipv6h->hop_limit--;
+       return 0;
+}
+
+static void ip6mr_forward2(struct net *net, struct mr_table *mrt,
+                          struct sk_buff *skb, int vifi)
+{
+       struct net_device *indev = skb->dev;
+
+       if (ip6mr_prepare_xmit(net, mrt, skb, vifi))
+               goto out_free;
 
        IP6CB(skb)->flags |= IP6SKB_FORWARDED;