ipv4: gso: make inet_gso_segment() stackable

In order to support GSO on IPIP, we need to make
inet_gso_segment() stackable.

It should not assume network header starts right after mac
header.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ba74474..cad1e0c 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2722,9 +2722,12 @@ static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
 /* Keeps track of mac header offset relative to skb->head.
  * It is useful for TSO of Tunneling protocol. e.g. GRE.
  * For non-tunnel skb it points to skb_mac_header() and for
- * tunnel skb it points to outer mac header. */
+ * tunnel skb it points to outer mac header.
+ * Keeps track of level of encapsulation of network headers.
+ */
 struct skb_gso_cb {
-       int mac_offset;
+       int     mac_offset;
+       int     encap_level;
 };
 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
 

diff --git a/net/core/dev.c b/net/core/dev.c
index 1b6eadf..0918aad 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2377,6 +2377,8 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
        }
 
        SKB_GSO_CB(skb)->mac_offset = skb_headroom(skb);
+       SKB_GSO_CB(skb)->encap_level = 0;
+
        skb_reset_mac_header(skb);
        skb_reset_mac_len(skb);
 

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 4f8cd4f..5783ab5 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1273,16 +1273,17 @@ out:
 }
 
 static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
-       netdev_features_t features)
+                                       netdev_features_t features)
 {
        struct sk_buff *segs = ERR_PTR(-EINVAL);
        const struct net_offload *ops;
+       unsigned int offset = 0;
        struct iphdr *iph;
+       bool tunnel;
        int proto;
+       int nhoff;
        int ihl;
        int id;
-       unsigned int offset = 0;
-       bool tunnel;
 
        if (unlikely(skb_shinfo(skb)->gso_type &
                     ~(SKB_GSO_TCPV4 |
@@ -1296,6 +1297,8 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
                       0)))
                goto out;
 
+       skb_reset_network_header(skb);
+       nhoff = skb_network_header(skb) - skb_mac_header(skb);
        if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
                goto out;
 
@@ -1312,7 +1315,10 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
                goto out;
        __skb_pull(skb, ihl);
 
-       tunnel = !!skb->encapsulation;
+       tunnel = SKB_GSO_CB(skb)->encap_level > 0;
+       if (tunnel)
+               features = skb->dev->hw_enc_features & netif_skb_features(skb);
+       SKB_GSO_CB(skb)->encap_level += ihl;
 
        skb_reset_transport_header(skb);
 
@@ -1327,18 +1333,23 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
 
        skb = segs;
        do {
-               iph = ip_hdr(skb);
+               iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
                if (!tunnel && proto == IPPROTO_UDP) {
                        iph->id = htons(id);
                        iph->frag_off = htons(offset >> 3);
                        if (skb->next != NULL)
                                iph->frag_off |= htons(IP_MF);
-                       offset += (skb->len - skb->mac_len - iph->ihl * 4);
+                       offset += skb->len - nhoff - ihl;
                } else  {
                        iph->id = htons(id++);
                }
-               iph->tot_len = htons(skb->len - skb->mac_len);
+               iph->tot_len = htons(skb->len - nhoff);
                ip_send_check(iph);
+               if (tunnel) {
+                       skb_reset_inner_headers(skb);
+                       skb->encapsulation = 1;
+               }
+               skb->network_header = (u8 *)iph - skb->head;
        } while ((skb = skb->next));
 
 out: