[PATCH] tcp: fix build error if IPv6 is not enabled

[Eric Dumazet]

=46rom: Eric Dumazet <***@google.com>

$ make M=3Dnet/ipv4
CC net/ipv4/route.o
In file included from net/ipv4/route.c:102:0:
include/net/tcp.h: In function =E2=80=98tcp_v6_iif=E2=80=99:
include/net/tcp.h:738:32: error: =E2=80=98union <anonymous>=E2=80=99 ha=
s no member named =E2=80=98h6=E2=80=99
return TCP_SKB_CB(skb)->header.h6.iif;

Signed-off-by: Eric Dumazet <***@google.com>
=46ixes: 870c3151382c ("ipv6: introduce tcp_v6_iif()")
---
include/net/tcp.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index c9766f89deba..4062b4f0d121 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -730,6 +730,7 @@ struct tcp_skb_cb {
#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
=20
=20
+#if IS_ENABLED(CONFIG_IPV6)
/* This is the variant of inet6_iif() that must be used by TCP,
* as TCP moves IP6CB into a different location in skb->cb[]
*/
@@ -737,6 +738,7 @@ static inline int tcp_v6_iif(const struct sk_buff *=
skb)
{
return TCP_SKB_CB(skb)->header.h6.iif;
}
+#endif
=20
/* Due to TSO, an SKB can be composed of multiple actual
* packets. To keep these tracked properly, we use this.

[David Miller]

From: Eric Dumazet <***@gmail.com>
Date: Sat, 18 Oct 2014 08:34:37 -0700

$ make M=net/ipv4
CC net/ipv4/route.o
include/net/tcp.h:738:32: error: ‘union <anonymous>’ has no member named ‘h6’
return TCP_SKB_CB(skb)->header.h6.iif;
Fixes: 870c3151382c ("ipv6: introduce tcp_v6_ii