[PATCH net-next 1/7] net: ip: add drop reason to ip_route_input_noref()

[Menglong Dong]

The errno which ip_route_input_noref() returns can be used and checked by
the caller, so it's complex to make ip_route_input_noref() return drop
reason.

Instead, we add the pointer of the skb drop reason to the function
arguments of ip_route_input_noref, and adjust all the callers of it.
Then, we can pass the skb drop reasons to the caller.

Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>
---
 drivers/net/ipvlan/ipvlan_l3s.c | 2 +-
 include/net/route.h             | 5 +++--
 net/core/lwt_bpf.c              | 2 +-
 net/ipv4/arp.c                  | 2 +-
 net/ipv4/ip_fragment.c          | 2 +-
 net/ipv4/ip_input.c             | 7 +++----
 net/ipv4/route.c                | 3 ++-
 net/ipv4/xfrm4_input.c          | 2 +-
 net/ipv4/xfrm4_protocol.c       | 2 +-
 9 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ipvlan/ipvlan_l3s.c b/drivers/net/ipvlan/ipvlan_l3s.c
index d5b05e803219..fbfdd8c00056 100644
--- a/drivers/net/ipvlan/ipvlan_l3s.c
+++ b/drivers/net/ipvlan/ipvlan_l3s.c
@@ -52,7 +52,7 @@ static struct sk_buff *ipvlan_l3_rcv(struct net_device *dev,
 		int err;
 
 		err = ip_route_input_noref(skb, ip4h->daddr, ip4h->saddr,
-					   ip4h->tos, sdev);
+					   ip4h->tos, sdev, NULL);
 		if (unlikely(err))
 			goto out;
 		break;
diff --git a/include/net/route.h b/include/net/route.h
index 1789f1e6640b..cb9f31080517 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -202,7 +202,8 @@ int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 			  u8 tos, struct net_device *dev,
 			  struct in_device *in_dev, u32 *itag);
 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
-			 u8 tos, struct net_device *devin);
+			 u8 tos, struct net_device *devin,
+			 enum skb_drop_reason *reason);
 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
 		      u8 tos, struct net_device *devin,
 		      const struct sk_buff *hint);
@@ -213,7 +214,7 @@ static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 	int err;
 
 	rcu_read_lock();
-	err = ip_route_input_noref(skb, dst, src, tos, devin);
+	err = ip_route_input_noref(skb, dst, src, tos, devin, NULL);
 	if (!err) {
 		skb_dst_force(skb);
 		if (!skb_dst(skb))
diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index 1a14f915b7a4..df50f2977c90 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -96,7 +96,7 @@ static int bpf_lwt_input_reroute(struct sk_buff *skb)
 		dev_hold(dev);
 		skb_dst_drop(skb);
 		err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
-					   iph->tos, dev);
+					   iph->tos, dev, NULL);
 		dev_put(dev);
 	} else if (skb->protocol == htons(ETH_P_IPV6)) {
 		skb_dst_drop(skb);
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 11c1519b3699..a9dac0ef2be6 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -835,7 +835,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
 	}
 
 	if (arp->ar_op == htons(ARPOP_REQUEST) &&
-	    ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
+	    ip_route_input_noref(skb, tip, sip, 0, dev, NULL) == 0) {
 
 		rt = skb_rtable(skb);
 		addr_type = rt->rt_type;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index a92664a5ef2e..cdc75cfc1826 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -176,7 +176,7 @@ static void ip_expire(struct timer_list *t)
 	/* skb has no dst, perform route lookup again */
 	iph = ip_hdr(head);
 	err = ip_route_input_noref(head, iph->daddr, iph->saddr,
-					   iph->tos, head->dev);
+					   iph->tos, head->dev, NULL);
 	if (err)
 		goto out;
 
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index b6e7d4921309..dc062ae49137 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -318,12 +318,11 @@ static int ip_rcv_finish_core(struct net *net, struct sock *sk,
 			      struct sk_buff *skb, struct net_device *dev,
 			      const struct sk_buff *hint)
 {
+	enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	const struct iphdr *iph = ip_hdr(skb);
-	int err, drop_reason;
+	int err;
 	struct rtable *rt;
 
-	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
-
 	if (ip_can_use_hint(skb, iph, hint)) {
 		err = ip_route_use_hint(skb, iph->daddr, iph->saddr, iph->tos,
 					dev, hint);
@@ -363,7 +362,7 @@ static int ip_rcv_finish_core(struct net *net, struct sock *sk,
 	 */
 	if (!skb_valid_dst(skb)) {
 		err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
-					   iph->tos, dev);
+					   iph->tos, dev, &drop_reason);
 		if (unlikely(err))
 			goto drop_error;
 	} else {
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 723ac9181558..f1767e0cc9d9 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2465,7 +2465,8 @@ static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 }
 
 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-			 u8 tos, struct net_device *dev)
+			 u8 tos, struct net_device *dev,
+			 enum skb_drop_reason *reason)
 {
 	struct fib_result res;
 	int err;
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index a620618cc568..14990cc30c68 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -33,7 +33,7 @@ static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
 		const struct iphdr *iph = ip_hdr(skb);
 
 		if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
-					 iph->tos, skb->dev))
+					 iph->tos, skb->dev, NULL))
 			goto drop;
 	}
 
diff --git a/net/ipv4/xfrm4_protocol.c b/net/ipv4/xfrm4_protocol.c
index b146ce88c5d0..9678ff876169 100644
--- a/net/ipv4/xfrm4_protocol.c
+++ b/net/ipv4/xfrm4_protocol.c
@@ -76,7 +76,7 @@ int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
 		const struct iphdr *iph = ip_hdr(skb);
 
 		if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
-					 iph->tos, skb->dev))
+					 iph->tos, skb->dev, NULL))
 			goto drop;
 	}
 
-- 
2.39.5