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Commit 0d240e78 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

net: vrf: Implement get_saddr for IPv6 



IPv6 source address selection needs to consider the real egress route.
Similar to IPv4 implement a get_saddr6 method which is called if
source address has not been set.  The get_saddr6 method does a full
lookup which means pulling a route from the VRF FIB table and properly
considering linklocal/multicast destination addresses. Lookup failures
(eg., unreachable) then cause the source address selection to fail
which gets propagated back to the caller.

Signed-off-by: default avatarDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a2e2ff56

drivers/net/vrf.c

+41 −0
Original line number Diff line number Diff line
@@ -999,6 +999,46 @@ static struct dst_entry *vrf_get_rt6_dst(const struct net_device *dev, 


	return dst;

}



/* called under rcu_read_lock */

static int vrf_get_saddr6(struct net_device *dev, const struct sock *sk,

			  struct flowi6 *fl6)

{

	struct net *net = dev_net(dev);

	struct dst_entry *dst;

	struct rt6_info *rt;

	int err;



	if (rt6_need_strict(&fl6->daddr)) {

		rt = vrf_ip6_route_lookup(net, dev, fl6, fl6->flowi6_oif,

					  RT6_LOOKUP_F_IFACE);

		if (unlikely(!rt))

			return 0;



		dst = &rt->dst;

	} else {

		__u8 flags = fl6->flowi6_flags;



		fl6->flowi6_flags |= FLOWI_FLAG_L3MDEV_SRC;

		fl6->flowi6_flags |= FLOWI_FLAG_SKIP_NH_OIF;



		dst = ip6_route_output(net, sk, fl6);

		rt = (struct rt6_info *)dst;



		fl6->flowi6_flags = flags;

	}



	err = dst->error;

	if (!err) {

		err = ip6_route_get_saddr(net, rt, &fl6->daddr,

					  sk ? inet6_sk(sk)->srcprefs : 0,

					  &fl6->saddr);

	}



	dst_release(dst);



	return err;

}

#endif



static const struct l3mdev_ops vrf_l3mdev_ops = {
@@ -1008,6 +1048,7 @@ static const struct l3mdev_ops vrf_l3mdev_ops = { 
	.l3mdev_l3_rcv		= vrf_l3_rcv,

#if IS_ENABLED(CONFIG_IPV6)

	.l3mdev_get_rt6_dst	= vrf_get_rt6_dst,

	.l3mdev_get_saddr6	= vrf_get_saddr6,

#endif

};

include/net/l3mdev.h

+11 −0
Original line number Diff line number Diff line
@@ -39,6 +39,9 @@ struct l3mdev_ops { 
	/* IPv6 ops */

	struct dst_entry * (*l3mdev_get_rt6_dst)(const struct net_device *dev,

						 struct flowi6 *fl6);

	int		   (*l3mdev_get_saddr6)(struct net_device *dev,

						const struct sock *sk,

						struct flowi6 *fl6);

};



#ifdef CONFIG_NET_L3_MASTER_DEV
@@ -140,6 +143,8 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex) 
int l3mdev_get_saddr(struct net *net, int ifindex, struct flowi4 *fl4);



struct dst_entry *l3mdev_get_rt6_dst(struct net *net, struct flowi6 *fl6);

int l3mdev_get_saddr6(struct net *net, const struct sock *sk,

		      struct flowi6 *fl6);



static inline

struct sk_buff *l3mdev_l3_rcv(struct sk_buff *skb, u16 proto)
@@ -230,6 +235,12 @@ struct dst_entry *l3mdev_get_rt6_dst(struct net *net, struct flowi6 *fl6) 
	return NULL;

}



static inline int l3mdev_get_saddr6(struct net *net, const struct sock *sk,

				    struct flowi6 *fl6)

{

	return 0;

}



static inline

struct sk_buff *l3mdev_ip_rcv(struct sk_buff *skb)

{

net/ipv6/ip6_output.c

+10 −2
Original line number Diff line number Diff line
@@ -910,6 +910,13 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, 
	int err;

	int flags = 0;



	if (ipv6_addr_any(&fl6->saddr) && fl6->flowi6_oif &&

	    (!*dst || !(*dst)->error)) {

		err = l3mdev_get_saddr6(net, sk, fl6);

		if (err)

			goto out_err;

	}



	/* The correct way to handle this would be to do

	 * ip6_route_get_saddr, and then ip6_route_output; however,

	 * the route-specific preferred source forces the
@@ -999,10 +1006,11 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, 
	return 0;



out_err_release:

	if (err == -ENETUNREACH)

		IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);

	dst_release(*dst);

	*dst = NULL;

out_err:

	if (err == -ENETUNREACH)

		IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);

	return err;

}

net/l3mdev/l3mdev.c

+24 −0
Original line number Diff line number Diff line
@@ -162,6 +162,30 @@ int l3mdev_get_saddr(struct net *net, int ifindex, struct flowi4 *fl4) 
}

EXPORT_SYMBOL_GPL(l3mdev_get_saddr);



int l3mdev_get_saddr6(struct net *net, const struct sock *sk,

		      struct flowi6 *fl6)

{

	struct net_device *dev;

	int rc = 0;



	if (fl6->flowi6_oif) {

		rcu_read_lock();



		dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);

		if (dev && netif_is_l3_slave(dev))

			dev = netdev_master_upper_dev_get_rcu(dev);



		if (dev && netif_is_l3_master(dev) &&

		    dev->l3mdev_ops->l3mdev_get_saddr6)

			rc = dev->l3mdev_ops->l3mdev_get_saddr6(dev, sk, fl6);



		rcu_read_unlock();

	}



	return rc;

}

EXPORT_SYMBOL_GPL(l3mdev_get_saddr6);



/**

 *	l3mdev_fib_rule_match - Determine if flowi references an

 *				L3 master device