gre: refactor the gre_fb_xmit

The patch refactors the gre_fb_xmit function, by creating
prepare_fb_xmit function for later ERSPAN collect_md mode patch.

Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index f70674799fdd98cf856106ff8688dd7ba61c27ab..453b7925b940c62d0cd498bc766ee3523e715806 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -432,39 +432,33 @@ static struct rtable *gre_get_rt(struct sk_buff *skb,
        return ip_route_output_key(net, fl);
 }
 
-static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
-                       __be16 proto)
+static struct rtable *prepare_fb_xmit(struct sk_buff *skb,
+                                     struct net_device *dev,
+                                     struct flowi4 *fl,
+                                     int tunnel_hlen)
 {
        struct ip_tunnel_info *tun_info;
        const struct ip_tunnel_key *key;
        struct rtable *rt = NULL;
-       struct flowi4 fl;
        int min_headroom;
-       int tunnel_hlen;
-       __be16 df, flags;
        bool use_cache;
        int err;
 
        tun_info = skb_tunnel_info(skb);
-       if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
-                    ip_tunnel_info_af(tun_info) != AF_INET))
-               goto err_free_skb;
-
        key = &tun_info->key;
        use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
+
        if (use_cache)
-               rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl.saddr);
+               rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl->saddr);
        if (!rt) {
-               rt = gre_get_rt(skb, dev, &fl, key);
+               rt = gre_get_rt(skb, dev, fl, key);
                if (IS_ERR(rt))
-                               goto err_free_skb;
+                       goto err_free_skb;
                if (use_cache)
                        dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
-                                         fl.saddr);
+                                         fl->saddr);
        }
 
-       tunnel_hlen = gre_calc_hlen(key->tun_flags);
-
        min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
                        + tunnel_hlen + sizeof(struct iphdr);
        if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
@@ -476,6 +470,37 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
                if (unlikely(err))
                        goto err_free_rt;
        }
+       return rt;
+
+err_free_rt:
+       ip_rt_put(rt);
+err_free_skb:
+       kfree_skb(skb);
+       dev->stats.tx_dropped++;
+       return NULL;
+}
+
+static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
+                       __be16 proto)
+{
+       struct ip_tunnel_info *tun_info;
+       const struct ip_tunnel_key *key;
+       struct rtable *rt = NULL;
+       struct flowi4 fl;
+       int tunnel_hlen;
+       __be16 df, flags;
+
+       tun_info = skb_tunnel_info(skb);
+       if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
+                    ip_tunnel_info_af(tun_info) != AF_INET))
+               goto err_free_skb;
+
+       key = &tun_info->key;
+       tunnel_hlen = gre_calc_hlen(key->tun_flags);
+
+       rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
+       if (!rt)
+               return;
 
        /* Push Tunnel header. */
        if (gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)))