[NET]: Treat CHECKSUM_PARTIAL as CHECKSUM_UNNECESSARY

When a transmitted packet is looped back directly, CHECKSUM_PARTIAL
maps to the semantics of CHECKSUM_UNNECESSARY.  Therefore we should
treat it as such in the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 8 insertions, 11 deletions

diff --git a/net/ipv4/ipvs/ip_vs_core.c b/net/ipv4/ipvs/ip_vs_core.c
index 62cfbed317bf..f005a2f929f4 100644
--- a/net/ipv4/ipvs/ip_vs_core.c
+++ b/net/ipv4/ipvs/ip_vs_core.c
@@ -681,8 +681,7 @@ static int ip_vs_out_icmp(struct sk_buff **pskb, int *related)
         }
 
         /* Ensure the checksum is correct */
-        if (skb->ip_summed != CHECKSUM_UNNECESSARY &&
-            ip_vs_checksum_complete(skb, ihl)) {
+        if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
                 /* Failed checksum! */
                 IP_VS_DBG(1, "Forward ICMP: failed checksum from %d.%d.%d.%d!\n",
                           NIPQUAD(iph->saddr));
@@ -921,8 +920,7 @@ ip_vs_in_icmp(struct sk_buff **pskb, int *related, unsigned int hooknum)
         verdict = NF_DROP;
 
         /* Ensure the checksum is correct */
-        if (skb->ip_summed != CHECKSUM_UNNECESSARY &&
-            ip_vs_checksum_complete(skb, ihl)) {
+        if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
                 /* Failed checksum! */
                 IP_VS_DBG(1, "Incoming ICMP: failed checksum from %d.%d.%d.%d!\n",
                           NIPQUAD(iph->saddr));
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9c3b4c7a50ad..d1604f59d77e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4009,7 +4009,7 @@ static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen)
         int err;
 
         local_bh_enable();
-        if (skb->ip_summed==CHECKSUM_UNNECESSARY)
+        if (skb_csum_unnecessary(skb))
                 err = skb_copy_datagram_iovec(skb, hlen, tp->ucopy.iov, chunk);
         else
                 err = skb_copy_and_csum_datagram_iovec(skb, hlen,
@@ -4041,7 +4041,7 @@ static __sum16 __tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb
 
 static inline int tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb)
 {
-        return skb->ip_summed != CHECKSUM_UNNECESSARY &&
+        return !skb_csum_unnecessary(skb) &&
                 __tcp_checksum_complete_user(sk, skb);
 }
 
@@ -4059,7 +4059,7 @@ static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, int hlen
         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
                 tp->ucopy.dma_chan = get_softnet_dma();
 
-        if (tp->ucopy.dma_chan && skb->ip_summed == CHECKSUM_UNNECESSARY) {
+        if (tp->ucopy.dma_chan && skb_csum_unnecessary(skb)) {
 
                 dma_cookie = dma_skb_copy_datagram_iovec(tp->ucopy.dma_chan,
                         skb, hlen, tp->ucopy.iov, chunk, tp->ucopy.pinned_list);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a091a99ad263..5a3e7f839fc5 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1638,8 +1638,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
          * Packet length and doff are validated by header prediction,
          * provided case of th->doff==0 is eliminated.
          * So, we defer the checks. */
-        if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
-             tcp_v4_checksum_init(skb)))
+        if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
                 goto bad_packet;
 
         th = tcp_hdr(skb);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5ad7a26e3091..cec0f2cc49b7 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -848,7 +848,7 @@ try_again:
                         goto csum_copy_err;
         }
 
-        if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+        if (skb_csum_unnecessary(skb))
                 err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
                                               msg->msg_iov, copied       );
         else {
@@ -1190,7 +1190,7 @@ static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
                                       proto, skb->csum))
                         skb->ip_summed = CHECKSUM_UNNECESSARY;
         }
-        if (skb->ip_summed != CHECKSUM_UNNECESSARY)
+        if (!skb_csum_unnecessary(skb))
                 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
                                                skb->len, proto, 0);
         /* Probably, we should checksum udp header (it should be in cache