Commit e58e4159 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

net: Enable support for VRF with ipv4 multicast 



Enable support for IPv4 multicast:
- similar to unicast the flow struct is updated to L3 master device
  if relevant prior to calling fib_rules_lookup. The table id is saved
  to the lookup arg so the rule action for ipmr can return the table
  associated with the device.

- ip_mr_forward needs to check for master device mismatch as well
  since the skb->dev is set to it

- allow multicast address on VRF device for Rx by checking for the
  daddr in the VRF device as well as the original ingress device

- on Tx need to drop to __mkroute_output when FIB lookup fails for
  multicast destination address.

- if CONFIG_IP_MROUTE_MULTIPLE_TABLES is enabled VRF driver creates
  IPMR FIB rules on first device create similar to FIB rules. In
  addition the VRF driver does not divert IPv4 multicast packets:
  it breaks on Tx since the fib lookup fails on the mcast address.

With this patch, ipmr forwarding and local rx/tx work.

Signed-off-by: default avatarDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1c851758

drivers/net/vrf.c

+18 −5
Original line number Diff line number Diff line
@@ -272,11 +272,6 @@ static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb, 
	if (IS_ERR(rt))

		goto err;



	if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {

		ip_rt_put(rt);

		goto err;

	}



	skb_dst_drop(skb);



	/* if dst.dev is loopback or the VRF device again this is locally
@@ -611,6 +606,10 @@ static struct sk_buff *vrf_ip_out(struct net_device *vrf_dev, 
	struct dst_entry *dst = NULL;

	struct rtable *rth;



	/* don't divert multicast */

	if (ipv4_is_multicast(ip_hdr(skb)->daddr))

		return skb;



	rcu_read_lock();



	rth = rcu_dereference(vrf->rth);
@@ -999,6 +998,9 @@ static struct sk_buff *vrf_ip_rcv(struct net_device *vrf_dev, 
	skb->skb_iif = vrf_dev->ifindex;

	IPCB(skb)->flags |= IPSKB_L3SLAVE;



	if (ipv4_is_multicast(ip_hdr(skb)->daddr))

		goto out;



	/* loopback traffic; do not push through packet taps again.

	 * Reset pkt_type for upper layers to process skb

	 */
@@ -1162,8 +1164,19 @@ static int vrf_add_fib_rules(const struct net_device *dev) 
	if (err < 0)

		goto ipv6_err;



#if IS_ENABLED(CONFIG_IP_MROUTE_MULTIPLE_TABLES)

	err = vrf_fib_rule(dev, RTNL_FAMILY_IPMR, true);

	if (err < 0)

		goto ipmr_err;

#endif



	return 0;



#if IS_ENABLED(CONFIG_IP_MROUTE_MULTIPLE_TABLES)

ipmr_err:

	vrf_fib_rule(dev, AF_INET6,  false);

#endif



ipv6_err:

	vrf_fib_rule(dev, AF_INET,  false);

net/ipv4/ipmr.c

+12 −1
Original line number Diff line number Diff line
@@ -137,6 +137,9 @@ static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4, 
		.flags = FIB_LOOKUP_NOREF,

	};



	/* update flow if oif or iif point to device enslaved to l3mdev */

	l3mdev_update_flow(net, flowi4_to_flowi(flp4));



	err = fib_rules_lookup(net->ipv4.mr_rules_ops,

			       flowi4_to_flowi(flp4), 0, &arg);

	if (err < 0)
@@ -163,7 +166,9 @@ static int ipmr_rule_action(struct fib_rule *rule, struct flowi *flp, 
		return -EINVAL;

	}



	mrt = ipmr_get_table(rule->fr_net, rule->table);

	arg->table = fib_rule_get_table(rule, arg);



	mrt = ipmr_get_table(rule->fr_net, arg->table);

	if (!mrt)

		return -EAGAIN;

	res->mrt = mrt;
@@ -1809,6 +1814,12 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt, 


	/* Wrong interface: drop packet and (maybe) send PIM assert. */

	if (mrt->vif_table[vif].dev != skb->dev) {

		struct net_device *mdev;



		mdev = l3mdev_master_dev_rcu(mrt->vif_table[vif].dev);

		if (mdev == skb->dev)

			goto forward;



		if (rt_is_output_route(skb_rtable(skb))) {

			/* It is our own packet, looped back.

			 * Very complicated situation...

net/ipv4/route.c

+26 −15
Original line number Diff line number Diff line
@@ -1980,10 +1980,23 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	 */

	if (ipv4_is_multicast(daddr)) {

		struct in_device *in_dev = __in_dev_get_rcu(dev);

		int our = 0;



		if (in_dev) {

			int our = ip_check_mc_rcu(in_dev, daddr, saddr,

		if (in_dev)

			our = ip_check_mc_rcu(in_dev, daddr, saddr,

					      ip_hdr(skb)->protocol);



		/* check l3 master if no match yet */

		if ((!in_dev || !our) && netif_is_l3_slave(dev)) {

			struct in_device *l3_in_dev;



			l3_in_dev = __in_dev_get_rcu(skb->dev);

			if (l3_in_dev)

				our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,

						      ip_hdr(skb)->protocol);

		}



		res = -EINVAL;

		if (our

#ifdef CONFIG_IP_MROUTE

			||
@@ -1991,14 +2004,11 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
		     IN_DEV_MFORWARD(in_dev))

#endif

		   ) {

				int res = ip_route_input_mc(skb, daddr, saddr,

			res = ip_route_input_mc(skb, daddr, saddr,

						tos, dev, our);

				rcu_read_unlock();

				return res;

			}

		}

		rcu_read_unlock();

		return -EINVAL;

		return res;

	}

	res = ip_route_input_slow(skb, daddr, saddr, tos, dev);

	rcu_read_unlock();
@@ -2266,7 +2276,8 @@ struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 
		res.fi = NULL;

		res.table = NULL;

		if (fl4->flowi4_oif &&

		    !netif_index_is_l3_master(net, fl4->flowi4_oif)) {

		    (ipv4_is_multicast(fl4->daddr) ||

		    !netif_index_is_l3_master(net, fl4->flowi4_oif))) {

			/* Apparently, routing tables are wrong. Assume,

			   that the destination is on link.

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