Function udp_v4_early_demux() was already declared in 'include/net/udp.h',
no need to keep the extern in 'ip_input.c', which may produce the
following checkpatch warning:

  WARNING: externs should be avoided in .c files
  #45: FILE: net/ipv4/ip_input.c:322:
  +enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);

Replace it by including 'net/udp.h'. Do the same for tcp_v4_early_demux().

Signed-off-by: Wang Liang <wangliang74@huawei.com>
---
 net/ipv4/ip_input.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 273578579a6b..19d3141dad1f 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -141,6 +141,8 @@
 #include <linux/mroute.h>
 #include <linux/netlink.h>
 #include <net/dst_metadata.h>
+#include <net/udp.h>
+#include <net/tcp.h>
 
 /*
  *	Process Router Attention IP option (RFC 2113)
@@ -317,8 +319,6 @@ static bool ip_can_use_hint(const struct sk_buff *skb, const struct iphdr *iph,
 	       ip_hdr(hint)->tos == iph->tos;
 }
 
-int tcp_v4_early_demux(struct sk_buff *skb);
-enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);
 static int ip_rcv_finish_core(struct net *net,
 			      struct sk_buff *skb, struct net_device *dev,
 			      const struct sk_buff *hint)
-- 
2.34.1