gre: Create common functions for transmit

Create common functions for both IPv4 and IPv6 GRE in transmit. These
are put into gre.h.

Common functions are for:
  - GRE checksum calculation. Move gre_checksum to gre.h.
  - Building a GRE header. Move GRE build_header and rename
    gre_build_header.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/gre.h b/include/net/gre.h
index 3959158..29e3732 100644 (file)
--- a/include/net/gre.h
+++ b/include/net/gre.h
@@ -85,4 +85,48 @@ static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
        return flags;
 }
 
+static inline __sum16 gre_checksum(struct sk_buff *skb)
+{
+       __wsum csum;
+
+       if (skb->ip_summed == CHECKSUM_PARTIAL)
+               csum = lco_csum(skb);
+       else
+               csum = skb_checksum(skb, 0, skb->len, 0);
+       return csum_fold(csum);
+}
+
+static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
+                                   __be16 flags, __be16 proto,
+                                   __be32 key, __be32 seq)
+{
+       struct gre_base_hdr *greh;
+
+       skb_push(skb, hdr_len);
+
+       skb_reset_transport_header(skb);
+       greh = (struct gre_base_hdr *)skb->data;
+       greh->flags = gre_tnl_flags_to_gre_flags(flags);
+       greh->protocol = proto;
+
+       if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
+               __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
+
+               if (flags & TUNNEL_SEQ) {
+                       *ptr = seq;
+                       ptr--;
+               }
+               if (flags & TUNNEL_KEY) {
+                       *ptr = key;
+                       ptr--;
+               }
+               if (flags & TUNNEL_CSUM &&
+                   !(skb_shinfo(skb)->gso_type &
+                     (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
+                       *ptr = 0;
+                       *(__sum16 *)ptr = gre_checksum(skb);
+               }
+       }
+}
+
 #endif

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index f6db3d6..2480d79 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -329,49 +329,6 @@ drop:
        return 0;
 }
 
-static __sum16 gre_checksum(struct sk_buff *skb)
-{
-       __wsum csum;
-
-       if (skb->ip_summed == CHECKSUM_PARTIAL)
-               csum = lco_csum(skb);
-       else
-               csum = skb_checksum(skb, 0, skb->len, 0);
-       return csum_fold(csum);
-}
-
-static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
-                        __be16 proto, __be32 key, __be32 seq)
-{
-       struct gre_base_hdr *greh;
-
-       skb_push(skb, hdr_len);
-
-       skb_reset_transport_header(skb);
-       greh = (struct gre_base_hdr *)skb->data;
-       greh->flags = gre_tnl_flags_to_gre_flags(flags);
-       greh->protocol = proto;
-
-       if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
-               __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
-
-               if (flags & TUNNEL_SEQ) {
-                       *ptr = seq;
-                       ptr--;
-               }
-               if (flags & TUNNEL_KEY) {
-                       *ptr = key;
-                       ptr--;
-               }
-               if (flags & TUNNEL_CSUM &&
-                   !(skb_shinfo(skb)->gso_type &
-                     (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
-                       *ptr = 0;
-                       *(__sum16 *)ptr = gre_checksum(skb);
-               }
-       }
-}
-
 static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
                       const struct iphdr *tnl_params,
                       __be16 proto)
@@ -382,8 +339,9 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
                tunnel->o_seqno++;
 
        /* Push GRE header. */
-       build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
-                    proto, tunnel->parms.o_key, htonl(tunnel->o_seqno));
+       gre_build_header(skb, tunnel->tun_hlen,
+                        tunnel->parms.o_flags, proto, tunnel->parms.o_key,
+                        htonl(tunnel->o_seqno));
 
        skb_set_inner_protocol(skb, proto);
        ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
@@ -460,8 +418,8 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
                goto err_free_rt;
 
        flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
-       build_header(skb, tunnel_hlen, flags, htons(ETH_P_TEB),
-                    tunnel_id_to_key(tun_info->key.tun_id), 0);
+       gre_build_header(skb, tunnel_hlen, flags, htons(ETH_P_TEB),
+                        tunnel_id_to_key(tun_info->key.tun_id), 0);
 
        df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;