udp: move logic out of udp[46]_ufo_send_check

In udp[46]_ufo_send_check the UDP checksum initialized to the pseudo
header checksum. We can move this logic into udp[46]_ufo_fragment.
After this change udp[64]_ufo_send_check is a no-op.

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

2 files changed, 33 insertions, 44 deletions

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index d7c43f764c71..2918cc914824 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -27,23 +27,6 @@ struct udp_offload_priv {
 
 static int udp4_ufo_send_check(struct sk_buff *skb)
 {
-        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
-                return -EINVAL;
-
-        if (likely(!skb->encapsulation)) {
-                const struct iphdr *iph;
-                struct udphdr *uh;
-
-                iph = ip_hdr(skb);
-                uh = udp_hdr(skb);
-
-                uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
-                                IPPROTO_UDP, 0);
-                skb->csum_start = skb_transport_header(skb) - skb->head;
-                skb->csum_offset = offsetof(struct udphdr, check);
-                skb->ip_summed = CHECKSUM_PARTIAL;
-        }
-
         return 0;
 }
 
@@ -128,8 +111,9 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 {
         struct sk_buff *segs = ERR_PTR(-EINVAL);
         unsigned int mss;
-        int offset;
         __wsum csum;
+        struct udphdr *uh;
+        struct iphdr *iph;
 
         if (skb->encapsulation &&
             (skb_shinfo(skb)->gso_type &
@@ -138,6 +122,9 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
                 goto out;
         }
 
+        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
+                goto out;
+
         mss = skb_shinfo(skb)->gso_size;
         if (unlikely(skb->len <= mss))
                 goto out;
@@ -165,10 +152,16 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
          * HW cannot do checksum of UDP packets sent as multiple
          * IP fragments.
          */
-        offset = skb_checksum_start_offset(skb);
-        csum = skb_checksum(skb, offset, skb->len - offset, 0);
-        offset += skb->csum_offset;
-        *(__sum16 *)(skb->data + offset) = csum_fold(csum);
+
+        uh = udp_hdr(skb);
+        iph = ip_hdr(skb);
+
+        uh->check = 0;
+        csum = skb_checksum(skb, 0, skb->len, 0);
+        uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
+        if (uh->check == 0)
+                uh->check = CSUM_MANGLED_0;
+
         skb->ip_summed = CHECKSUM_NONE;
 
         /* Fragment the skb. IP headers of the fragments are updated in
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index de85f809bf29..e4af6437ea3b 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -19,23 +19,6 @@
 
 static int udp6_ufo_send_check(struct sk_buff *skb)
 {
-        const struct ipv6hdr *ipv6h;
-        struct udphdr *uh;
-
-        if (!pskb_may_pull(skb, sizeof(*uh)))
-                return -EINVAL;
-
-        if (likely(!skb->encapsulation)) {
-                ipv6h = ipv6_hdr(skb);
-                uh = udp_hdr(skb);
-
-                uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
-                                             IPPROTO_UDP, 0);
-                skb->csum_start = skb_transport_header(skb) - skb->head;
-                skb->csum_offset = offsetof(struct udphdr, check);
-                skb->ip_summed = CHECKSUM_PARTIAL;
-        }
-
         return 0;
 }
 
@@ -49,7 +32,6 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
         u8 *packet_start, *prevhdr;
         u8 nexthdr;
         u8 frag_hdr_sz = sizeof(struct frag_hdr);
-        int offset;
         __wsum csum;
         int tnl_hlen;
 
@@ -83,13 +65,27 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
             (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
                 segs = skb_udp_tunnel_segment(skb, features);
         else {
+                const struct ipv6hdr *ipv6h;
+                struct udphdr *uh;
+
+                if (!pskb_may_pull(skb, sizeof(struct udphdr)))
+                        goto out;
+
                 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
                  * do checksum of UDP packets sent as multiple IP fragments.
                  */
-                offset = skb_checksum_start_offset(skb);
-                csum = skb_checksum(skb, offset, skb->len - offset, 0);
-                offset += skb->csum_offset;
-                *(__sum16 *)(skb->data + offset) = csum_fold(csum);
+
+                uh = udp_hdr(skb);
+                ipv6h = ipv6_hdr(skb);
+
+                uh->check = 0;
+                csum = skb_checksum(skb, 0, skb->len, 0);
+                uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
+                                          &ipv6h->daddr, csum);
+
+                if (uh->check == 0)
+                        uh->check = CSUM_MANGLED_0;
+
                 skb->ip_summed = CHECKSUM_NONE;
 
                 /* Check if there is enough headroom to insert fragment header. */