tcp: Handle CHECKSUM_PARTIAL for SYNACK packets for IPv6

tcp: Handle CHECKSUM_PARTIAL for SYNACK packets for IPv6

This patch moves the common code between tcp_v6_send_check and
tcp_v6_gso_send_check into a new function __tcp_v6_send_check.

It then uses the new function in tcp_v6_send_synack as well as
tcp_v6_send_response so that they handle CHECKSUM_PARTIAL properly.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Yinghai <yinghai.lu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 18 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c92ebe8f80d5..f84c506c588a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -75,6 +75,9 @@ static void	tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
                                       struct request_sock *req);
 
 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
+static void     __tcp_v6_send_check(struct sk_buff *skb,
+                                    struct in6_addr *saddr,
+                                    struct in6_addr *daddr);
 
 static const struct inet_connection_sock_af_ops ipv6_mapped;
 static const struct inet_connection_sock_af_ops ipv6_specific;
@@ -503,11 +506,7 @@ static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
 
         skb = tcp_make_synack(sk, dst, req, rvp);
         if (skb) {
-                struct tcphdr *th = tcp_hdr(skb);
-
-                th->check = tcp_v6_check(skb->len,
-                                         &treq->loc_addr, &treq->rmt_addr,
-                                         csum_partial(th, skb->len, skb->csum));
+                __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
 
                 ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
                 err = ip6_xmit(sk, skb, &fl, opt, 0);
@@ -918,22 +917,29 @@ static struct timewait_sock_ops tcp6_timewait_sock_ops = {
         .twsk_destructor= tcp_twsk_destructor,
 };
 
-static void tcp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
+static void __tcp_v6_send_check(struct sk_buff *skb,
+                                struct in6_addr *saddr, struct in6_addr *daddr)
 {
-        struct ipv6_pinfo *np = inet6_sk(sk);
         struct tcphdr *th = tcp_hdr(skb);
 
         if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                th->check = ~csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP,  0);
+                th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
                 skb->csum_start = skb_transport_header(skb) - skb->head;
                 skb->csum_offset = offsetof(struct tcphdr, check);
         } else {
-                th->check = csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP,
-                                            csum_partial(th, th->doff<<2,
-                                                         skb->csum));
+                th->check = tcp_v6_check(skb->len, saddr, daddr,
+                                         csum_partial(th, th->doff << 2,
+                                                      skb->csum));
         }
 }
 
+static void tcp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
+{
+        struct ipv6_pinfo *np = inet6_sk(sk);
+
+        __tcp_v6_send_check(skb, &np->saddr, &np->daddr);
+}
+
 static int tcp_v6_gso_send_check(struct sk_buff *skb)
 {
         struct ipv6hdr *ipv6h;
@@ -946,11 +952,8 @@ static int tcp_v6_gso_send_check(struct sk_buff *skb)
         th = tcp_hdr(skb);
 
         th->check = 0;
-        th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
-                                     IPPROTO_TCP, 0);
-        skb->csum_start = skb_transport_header(skb) - skb->head;
-        skb->csum_offset = offsetof(struct tcphdr, check);
         skb->ip_summed = CHECKSUM_PARTIAL;
+        __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
         return 0;
 }
 
@@ -1053,9 +1056,7 @@ static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
         ipv6_addr_copy(&fl.fl6_src, &ipv6_hdr(skb)->daddr);
 
-        t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
-                                    tot_len, IPPROTO_TCP,
-                                    buff->csum);
+        __tcp_v6_send_check(buff, &fl.fl6_src, &fl.fl6_dst);
 
         fl.proto = IPPROTO_TCP;
         fl.oif = inet6_iif(skb);