Commit 5b92112a authored by Menglong Dong's avatar Menglong Dong Committed by Paolo Abeni
Browse files

net: ip: make ip_route_input_slow() return drop reasons 



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: default avatarMenglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent d46f8270

include/net/dropreason-core.h

+6 −0
Original line number Diff line number Diff line
@@ -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)

net/ipv4/route.c

+35 −21
Original line number Diff line number Diff line
@@ -2217,7 +2217,8 @@ 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,

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)

{
@@ -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;
@@ -2260,22 +2263,30 @@ 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;

		}

	}



	/*

	 *	Now we are ready to route packet.
@@ -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 @@ 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;

		}

	}
@@ -2399,7 +2417,7 @@ 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:
@@ -2420,12 +2438,8 @@ 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:
@@ -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,