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 <>
Signed-off-by: default avatarDavid S. Miller <>
parent 1c851758
......@@ -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) {
goto err;
/* if 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;
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;
err = vrf_fib_rule(dev, RTNL_FAMILY_IPMR, true);
if (err < 0)
goto ipmr_err;
return 0;
vrf_fib_rule(dev, AF_INET6, false);
vrf_fib_rule(dev, AF_INET, false);
......@@ -137,6 +137,9 @@ static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,
/* 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...
......@@ -1980,25 +1980,35 @@ 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 (our
if (in_dev)
our = ip_check_mc_rcu(in_dev, daddr, saddr,
/* 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,
res = -EINVAL;
if (our
(!ipv4_is_local_multicast(daddr) &&
(!ipv4_is_local_multicast(daddr) &&
) {
int res = ip_route_input_mc(skb, daddr, saddr,
tos, dev, our);
return res;
) {
res = ip_route_input_mc(skb, daddr, saddr,
tos, dev, our);
return -EINVAL;
return res;
res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
......@@ -2266,7 +2276,8 @@ struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, = 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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