udp: Move udp_tunnel_segment into udp_offload.c

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

1 files changed, 76 insertions, 0 deletions

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 546d2d439dda..4807544d018b 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -47,6 +47,82 @@ static int udp4_ufo_send_check(struct sk_buff *skb)
         return 0;
 }
 
+struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
+                                       netdev_features_t features)
+{
+        struct sk_buff *segs = ERR_PTR(-EINVAL);
+        u16 mac_offset = skb->mac_header;
+        int mac_len = skb->mac_len;
+        int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
+        __be16 protocol = skb->protocol;
+        netdev_features_t enc_features;
+        int udp_offset, outer_hlen;
+        unsigned int oldlen;
+        bool need_csum;
+
+        oldlen = (u16)~skb->len;
+
+        if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
+                goto out;
+
+        skb->encapsulation = 0;
+        __skb_pull(skb, tnl_hlen);
+        skb_reset_mac_header(skb);
+        skb_set_network_header(skb, skb_inner_network_offset(skb));
+        skb->mac_len = skb_inner_network_offset(skb);
+        skb->protocol = htons(ETH_P_TEB);
+
+        need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
+        if (need_csum)
+                skb->encap_hdr_csum = 1;
+
+        /* segment inner packet. */
+        enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
+        segs = skb_mac_gso_segment(skb, enc_features);
+        if (!segs || IS_ERR(segs)) {
+                skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
+                                     mac_len);
+                goto out;
+        }
+
+        outer_hlen = skb_tnl_header_len(skb);
+        udp_offset = outer_hlen - tnl_hlen;
+        skb = segs;
+        do {
+                struct udphdr *uh;
+                int len;
+
+                skb_reset_inner_headers(skb);
+                skb->encapsulation = 1;
+
+                skb->mac_len = mac_len;
+
+                skb_push(skb, outer_hlen);
+                skb_reset_mac_header(skb);
+                skb_set_network_header(skb, mac_len);
+                skb_set_transport_header(skb, udp_offset);
+                len = skb->len - udp_offset;
+                uh = udp_hdr(skb);
+                uh->len = htons(len);
+
+                if (need_csum) {
+                        __be32 delta = htonl(oldlen + len);
+
+                        uh->check = ~csum_fold((__force __wsum)
+                                               ((__force u32)uh->check +
+                                                (__force u32)delta));
+                        uh->check = gso_make_checksum(skb, ~uh->check);
+
+                        if (uh->check == 0)
+                                uh->check = CSUM_MANGLED_0;
+                }
+
+                skb->protocol = protocol;
+        } while ((skb = skb->next));
+out:
+        return segs;
+}
+
 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
                                          netdev_features_t features)
 {