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Commit b5bdacf3 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

net: Propagate lookup failure in l3mdev_get_saddr to caller 



Commands run in a vrf context are not failing as expected on a route lookup:
    root@kenny:~# ip ro ls table vrf-red
    unreachable default

    root@kenny:~# ping -I vrf-red -c1 -w1 10.100.1.254
    ping: Warning: source address might be selected on device other than vrf-red.
    PING 10.100.1.254 (10.100.1.254) from 0.0.0.0 vrf-red: 56(84) bytes of data.

    --- 10.100.1.254 ping statistics ---
    2 packets transmitted, 0 received, 100% packet loss, time 999ms

Since the vrf table does not have a route for 10.100.1.254 the ping
should have failed. The saddr lookup causes a full VRF table lookup.
Propogating a lookup failure to the user allows the command to fail as
expected:

    root@kenny:~# ping -I vrf-red -c1 -w1 10.100.1.254
    connect: No route to host

Signed-off-by: default avatarDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7ec2541a

drivers/net/vrf.c

+7 −3
Original line number Diff line number Diff line
@@ -800,7 +800,7 @@ static struct rtable *vrf_get_rtable(const struct net_device *dev, 
}



/* called under rcu_read_lock */

static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)

static int vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)

{

	struct fib_result res = { .tclassid = 0 };

	struct net *net = dev_net(dev);
@@ -808,9 +808,10 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4) 
	u8 flags = fl4->flowi4_flags;

	u8 scope = fl4->flowi4_scope;

	u8 tos = RT_FL_TOS(fl4);

	int rc;



	if (unlikely(!fl4->daddr))

		return;

		return 0;



	fl4->flowi4_flags |= FLOWI_FLAG_SKIP_NH_OIF;

	fl4->flowi4_iif = LOOPBACK_IFINDEX;
@@ -818,7 +819,8 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4) 
	fl4->flowi4_scope = ((tos & RTO_ONLINK) ?

			     RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);



	if (!fib_lookup(net, fl4, &res, 0)) {

	rc = fib_lookup(net, fl4, &res, 0);

	if (!rc) {

		if (res.type == RTN_LOCAL)

			fl4->saddr = res.fi->fib_prefsrc ? : fl4->daddr;

		else
@@ -828,6 +830,8 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4) 
	fl4->flowi4_flags = flags;

	fl4->flowi4_tos = orig_tos;

	fl4->flowi4_scope = scope;



	return rc;

}



#if IS_ENABLED(CONFIG_IPV6)

include/net/l3mdev.h

+10 −6
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ struct l3mdev_ops { 
	/* IPv4 ops */

	struct rtable *	(*l3mdev_get_rtable)(const struct net_device *dev,

					     const struct flowi4 *fl4);

	void		(*l3mdev_get_saddr)(struct net_device *dev,

	int		(*l3mdev_get_saddr)(struct net_device *dev,

					    struct flowi4 *fl4);



	/* IPv6 ops */
@@ -112,10 +112,11 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex) 
	return rc;

}



static inline void l3mdev_get_saddr(struct net *net, int ifindex,

static inline int l3mdev_get_saddr(struct net *net, int ifindex,

				   struct flowi4 *fl4)

{

	struct net_device *dev;

	int rc = 0;



	if (ifindex) {
@@ -124,11 +125,13 @@ static inline void l3mdev_get_saddr(struct net *net, int ifindex, 
		dev = dev_get_by_index_rcu(net, ifindex);

		if (dev && netif_is_l3_master(dev) &&

		    dev->l3mdev_ops->l3mdev_get_saddr) {

			dev->l3mdev_ops->l3mdev_get_saddr(dev, fl4);

			rc = dev->l3mdev_ops->l3mdev_get_saddr(dev, fl4);

		}



		rcu_read_unlock();

	}



	return rc;

}



static inline struct dst_entry *l3mdev_get_rt6_dst(const struct net_device *dev,
@@ -200,9 +203,10 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex) 
	return false;

}



static inline void l3mdev_get_saddr(struct net *net, int ifindex,

static inline int l3mdev_get_saddr(struct net *net, int ifindex,

				   struct flowi4 *fl4)

{

	return 0;

}



static inline

include/net/route.h

+6 −1
Original line number Diff line number Diff line
@@ -283,7 +283,12 @@ static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 
			      sport, dport, sk);



	if (!src && oif) {

		l3mdev_get_saddr(net, oif, fl4);

		int rc;



		rc = l3mdev_get_saddr(net, oif, fl4);

		if (rc < 0)

			return ERR_PTR(rc);



		src = fl4->saddr;

	}

	if (!dst || !src) {

net/ipv4/raw.c

+5 −2
Original line number Diff line number Diff line
@@ -601,8 +601,11 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
			    (inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0),

			   daddr, saddr, 0, 0);



	if (!saddr && ipc.oif)

		l3mdev_get_saddr(net, ipc.oif, &fl4);

	if (!saddr && ipc.oif) {

		err = l3mdev_get_saddr(net, ipc.oif, &fl4);

		if (err < 0)

			goto done;

	}



	if (!inet->hdrincl) {

		rfv.msg = msg;

net/ipv4/udp.c

+5 −2
Original line number Diff line number Diff line
@@ -1025,8 +1025,11 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
				   flow_flags,

				   faddr, saddr, dport, inet->inet_sport);



		if (!saddr && ipc.oif)

			l3mdev_get_saddr(net, ipc.oif, fl4);

		if (!saddr && ipc.oif) {

			err = l3mdev_get_saddr(net, ipc.oif, fl4);

			if (err < 0)

				goto out;

		}



		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));

		rt = ip_route_output_flow(net, fl4, sk);