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net: ip: make ip_route_input_slow() return drop reasons

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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@chinatelecom.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Menglong Dong 2024-11-07 20:55:56 +08:00 committed by Paolo Abeni
parent d46f827016
commit 5b92112acd
2 changed files with 41 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/net/dropreason-core.h
View File

@ -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) \
@ -386,6 +387,11 @@ 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)

56
net/ipv4/route.c
View File

@ -2217,9 +2217,10 @@ 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);
@ -2249,8 +2250,10 @@ 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;
@ -2260,21 +2263,29 @@ 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;
}
}
/*
@ -2329,19 +2340,26 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
err = -EHOSTUNREACH;
goto no_route;
}
if (res->type != RTN_UNICAST)
if (res->type != RTN_UNICAST) {
reason = SKB_DROP_REASON_IP_INVALID_DEST;
goto martian_destination;
}
make_route:
err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, 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;
if (skb->protocol != htons(ETH_P_IP)) {
reason = SKB_DROP_REASON_INVALID_PROTO;
goto out;
}
if (!ipv4_is_zeronet(saddr)) {
err = -EINVAL;
reason = fib_validate_source_reason(skb, saddr, 0, dscp, 0,
dev, in_dev, &itag);
if (reason)
@ -2362,7 +2380,7 @@ local_input:
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;
}
}
@ -2399,7 +2417,7 @@ local_input:
rt_add_uncached_list(rth);
}
skb_dst_set(skb, &rth->dst);
err = 0;
reason = SKB_NOT_DROPPED_YET;
goto out;
no_route:
@ -2420,12 +2438,8 @@ martian_destination:
&daddr, &saddr, dev->name);
#endif
e_inval:
err = -EINVAL;
goto out;
e_nobufs:
err = -ENOBUFS;
reason = SKB_DROP_REASON_NOMEM;
goto out;
martian_source:
@ -2482,7 +2496,7 @@ 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,