In this commit, we make ip_route_input_slow() return skb drop reasons,
and following new skb drop reasons are added:
SKB_DROP_REASON_IP_INVALID_DEST
The only caller of ip_route_input_slow() is ip_route_input_rcu(), and we
adjust it by making it return -EINVAL on error.
Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>
---
include/net/dropreason-core.h | 6 +++++
net/ipv4/route.c | 51 +++++++++++++++++++++--------------
2 files changed, 37 insertions(+), 20 deletions(-)
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index 32d9fcb54af9..e53f3d944e04 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -79,6 +79,7 @@
FN(IP_LOCAL_SOURCE) \
FN(IP_INVALID_SOURCE) \
FN(IP_LOCALNET) \
+ FN(IP_INVALID_DEST) \
FN(PKT_TOO_BIG) \
FN(DUP_FRAG) \
FN(FRAG_REASM_TIMEOUT) \
@@ -378,6 +379,11 @@ enum skb_drop_reason {
SKB_DROP_REASON_IP_INVALID_SOURCE,
/** @SKB_DROP_REASON_IP_LOCALNET: source or dest ip is local net */
SKB_DROP_REASON_IP_LOCALNET,
+ /**
+ * @SKB_DROP_REASON_IP_INVALID_DEST: the dest ip is invalid:
+ * 1) dest ip is 0
+ */
+ SKB_DROP_REASON_IP_INVALID_DEST,
/**
* @SKB_DROP_REASON_PKT_TOO_BIG: packet size is too big (maybe exceed the
* MTU)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b41bb9be18e2..9b3f7bebcd86 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2207,10 +2207,12 @@ static struct net_device *ip_rt_get_dev(struct net *net,
* called with rcu_read_lock()
*/
-static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
- dscp_t dscp, struct net_device *dev,
- struct fib_result *res)
+static enum skb_drop_reason
+ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
+ dscp_t dscp, struct net_device *dev,
+ struct fib_result *res)
{
+ enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
struct in_device *in_dev = __in_dev_get_rcu(dev);
struct flow_keys *flkeys = NULL, _flkeys;
struct net *net = dev_net(dev);
@@ -2238,8 +2240,10 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
fl4.flowi4_tun_key.tun_id = 0;
skb_dst_drop(skb);
- if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
+ if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) {
+ reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
goto martian_source;
+ }
res->fi = NULL;
res->table = NULL;
@@ -2249,21 +2253,29 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
/* Accept zero addresses only to limited broadcast;
* I even do not know to fix it or not. Waiting for complains :-)
*/
- if (ipv4_is_zeronet(saddr))
+ if (ipv4_is_zeronet(saddr)) {
+ reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
goto martian_source;
+ }
- if (ipv4_is_zeronet(daddr))
+ if (ipv4_is_zeronet(daddr)) {
+ reason = SKB_DROP_REASON_IP_INVALID_DEST;
goto martian_destination;
+ }
/* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
* and call it once if daddr or/and saddr are loopback addresses
*/
if (ipv4_is_loopback(daddr)) {
- if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
+ if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
+ reason = SKB_DROP_REASON_IP_LOCALNET;
goto martian_destination;
+ }
} else if (ipv4_is_loopback(saddr)) {
- if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
+ if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
+ reason = SKB_DROP_REASON_IP_LOCALNET;
goto martian_source;
+ }
}
/*
@@ -2310,7 +2322,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
inet_dscp_to_dsfield(dscp), 0, dev,
in_dev, &itag);
if (err < 0) {
- err = -EINVAL;
+ reason = -err;
goto martian_source;
}
goto local_input;
@@ -2326,18 +2338,21 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
make_route:
err = ip_mkroute_input(skb, res, in_dev, daddr, saddr,
inet_dscp_to_dsfield(dscp), flkeys);
-out: return err;
+ if (!err)
+ reason = SKB_NOT_DROPPED_YET;
+
+out: return reason;
brd_input:
if (skb->protocol != htons(ETH_P_IP))
- goto e_inval;
+ goto out;
if (!ipv4_is_zeronet(saddr)) {
err = fib_validate_source(skb, saddr, 0,
inet_dscp_to_dsfield(dscp), 0, dev,
in_dev, &itag);
if (err < 0) {
- err = -EINVAL;
+ reason = -err;
goto martian_source;
}
}
@@ -2356,7 +2371,7 @@ out: return err;
rth = rcu_dereference(nhc->nhc_rth_input);
if (rt_cache_valid(rth)) {
skb_dst_set_noref(skb, &rth->dst);
- err = 0;
+ reason = SKB_NOT_DROPPED_YET;
goto out;
}
}
@@ -2393,7 +2408,7 @@ out: return err;
rt_add_uncached_list(rth);
}
skb_dst_set(skb, &rth->dst);
- err = 0;
+ reason = SKB_NOT_DROPPED_YET;
goto out;
no_route:
@@ -2414,12 +2429,8 @@ out: return err;
&daddr, &saddr, dev->name);
#endif
-e_inval:
- err = -EINVAL;
- goto out;
-
e_nobufs:
- err = -ENOBUFS;
+ reason = SKB_DROP_REASON_NOMEM;
goto out;
martian_source:
@@ -2477,7 +2488,7 @@ static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
return reason ? -EINVAL : 0;
}
- return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res);
+ return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res) ? -EINVAL : 0;
}
int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
--
2.39.5
