Commit f8696133 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

arp: Factorise ip_route_output() call in arp_req_set() and arp_req_delete(). 



When ioctl(SIOCDARP/SIOCSARP) is issued for non-proxy entry (no ATF_COM)
without arpreq.arp_dev[] set, arp_req_set() and arp_req_delete() looks up
dev based on IPv4 address by ip_route_output().

Let's factorise the same code as arp_req_dev().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240430015813.71143-4-kuniyu@amazon.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 05923674

net/ipv4/arp.c

+30 −20
Original line number Diff line number Diff line
@@ -1003,6 +1003,27 @@ static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 
 *	User level interface (ioctl)

 */



static struct net_device *arp_req_dev(struct net *net, struct arpreq *r)

{

	struct net_device *dev;

	struct rtable *rt;

	__be32 ip;



	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;



	rt = ip_route_output(net, ip, 0, 0, 0, RT_SCOPE_LINK);

	if (IS_ERR(rt))

		return ERR_CAST(rt);



	dev = rt->dst.dev;

	ip_rt_put(rt);



	if (!dev)

		return ERR_PTR(-EINVAL);



	return dev;

}



/*

 *	Set (create) an ARP cache entry.

 */
@@ -1045,25 +1066,17 @@ static int arp_req_set_public(struct net *net, struct arpreq *r, 
static int arp_req_set(struct net *net, struct arpreq *r,

		       struct net_device *dev)

{

	__be32 ip;

	struct neighbour *neigh;

	__be32 ip;

	int err;



	if (r->arp_flags & ATF_PUBL)

		return arp_req_set_public(net, r, dev);



	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;



	if (!dev) {

		struct rtable *rt = ip_route_output(net, ip, 0, 0, 0,

						    RT_SCOPE_LINK);



		if (IS_ERR(rt))

			return PTR_ERR(rt);

		dev = rt->dst.dev;

		ip_rt_put(rt);

		if (!dev)

			return -EINVAL;

		dev = arp_req_dev(net, r);

		if (IS_ERR(dev))

			return PTR_ERR(dev);

	}

	switch (dev->type) {

#if IS_ENABLED(CONFIG_FDDI)
@@ -1086,6 +1099,8 @@ static int arp_req_set(struct net *net, struct arpreq *r, 
		break;

	}



	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;



	neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);

	err = PTR_ERR(neigh);

	if (!IS_ERR(neigh)) {
@@ -1191,14 +1206,9 @@ static int arp_req_delete(struct net *net, struct arpreq *r, 


	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;

	if (!dev) {

		struct rtable *rt = ip_route_output(net, ip, 0, 0, 0,

						    RT_SCOPE_LINK);

		if (IS_ERR(rt))

			return PTR_ERR(rt);

		dev = rt->dst.dev;

		ip_rt_put(rt);

		if (!dev)

			return -EINVAL;

		dev = arp_req_dev(net, r);

		if (IS_ERR(dev))

			return PTR_ERR(dev);

	}

	return arp_invalidate(dev, ip, true);

}