[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 62cfbed..f005a2f 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 9c3b4c7..d1604f5 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 a091a99..5a3e7f8 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 5ad7a26..cec0f2c 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