Add support for locally originated traffic to VRF-local addresses. If
destination device for an skb is the loopback or VRF device then set
its dst to a local version of the VRF cached dst_entry and call netif_rx
to insert the packet onto the rx queue - similar to what is done for
loopback. This patch handles IPv4 support; follow on patch handles IPv6.
With this patch, ping, tcp and udp packets to a local IPv4 address are
successfully routed:
$ ip addr show dev eth1
4: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master
red state UP group default qlen 1000
link/ether 02:e0:f9:1c:b9:74 brd ff:ff:ff:ff:ff:ff
inet 10.100.1.1/24 brd 10.100.1.255 scope global eth1
valid_lft forever preferred_lft forever
inet6 2100:1::1/120 scope global
valid_lft forever preferred_lft forever
inet6 fe80::e0:f9ff:fe1c:b974/64 scope link
valid_lft forever preferred_lft forever
$ ping -c1 -I red 10.100.1.1
ping: Warning: source address might be selected on device other than red.
PING 10.100.1.1 (10.100.1.1) from 10.100.1.1 red: 56(84) bytes of data.
64 bytes from 10.100.1.1: icmp_seq=1 ttl=64 time=0.057 ms
This patch also enables use of IPv4 loopback address on the VRF device:
$ ip addr add dev red 127.0.0.1/8
$ ping -c1 -I red 127.0.0.1
PING 127.0.0.1 (127.0.0.1) from 127.0.0.1 red: 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.058 ms
Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
drivers/net/vrf.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 98 insertions(+), 2 deletions(-)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index ec0cb658d9ea..203d3c78a6e5 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -44,6 +44,7 @@
struct net_vrf {
struct rtable __rcu *rth;
+ struct rtable __rcu *rth_local;
struct rt6_info __rcu *rt6;
u32 tb_id;
};
@@ -54,9 +55,20 @@ struct pcpu_dstats {
u64 tx_drps;
u64 rx_pkts;
u64 rx_bytes;
+ u64 rx_drps;
struct u64_stats_sync syncp;
};
+static void vrf_rx_stats(struct net_device *dev, int len)
+{
+ struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
+
+ u64_stats_update_begin(&dstats->syncp);
+ dstats->rx_pkts++;
+ dstats->rx_bytes += len;
+ u64_stats_update_end(&dstats->syncp);
+}
+
static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
{
vrf_dev->stats.tx_errors++;
@@ -91,6 +103,34 @@ static struct rtnl_link_stats64 *vrf_get_stats64(struct
net_device *dev,
return stats;
}
+/* Local traffic destined to local address. Reinsert the packet to rx
+ * path, similar to loopback handling.
+ */
+static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev,
+ struct dst_entry *dst)
+{
+ int len = skb->len;
+
+ skb_orphan(skb);
+
+ skb_dst_set(skb, dst);
+ skb_dst_force(skb);
+
+ /* set pkt_type to avoid skb hitting packet taps twice -
+ * once on Tx and again in Rx processing
+ */
+ skb->pkt_type = PACKET_LOOPBACK;
+
+ skb->protocol = eth_type_trans(skb, dev);
+
+ if (likely(netif_rx(skb) == NET_RX_SUCCESS))
+ vrf_rx_stats(dev, len);
+ else
+ this_cpu_inc(dev->dstats->rx_drps);
+
+ return NETDEV_TX_OK;
+}
+
#if IS_ENABLED(CONFIG_IPV6)
static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
struct net_device *dev)
@@ -169,6 +209,34 @@ static netdev_tx_t vrf_process_v4_outbound(struct sk_buff
*skb,
}
skb_dst_drop(skb);
+
+ /* if dst.dev is loopback or the VRF device again this is locally
+ * originated traffic destined to a local address. Short circuit
+ * to Rx path using our local dst
+ */
+ if (rt->dst.dev == net->loopback_dev || rt->dst.dev == vrf_dev) {
+ struct net_vrf *vrf = netdev_priv(vrf_dev);
+ struct rtable *rth_local;
+ struct dst_entry *dst = NULL;
+
+ ip_rt_put(rt);
+
+ rcu_read_lock();
+
+ rth_local = rcu_dereference(vrf->rth_local);
+ if (likely(rth_local)) {
+ dst = &rth_local->dst;
+ dst_hold(dst);
+ }
+
+ rcu_read_unlock();
+
+ if (unlikely(!dst))
+ goto err;
+
+ return vrf_local_xmit(skb, vrf_dev, dst);
+ }
+
skb_dst_set(skb, &rt->dst);
/* strip the ethernet header added for pass through VRF device */
@@ -375,29 +443,48 @@ static int vrf_output(struct net *net, struct sock *sk,
struct sk_buff *skb)
static void vrf_rtable_release(struct net_vrf *vrf)
{
struct rtable *rth = rtnl_dereference(vrf->rth);
+ struct rtable *rth_local = rtnl_dereference(vrf->rth_local);
- rcu_assign_pointer(vrf->rth, NULL);
+ RCU_INIT_POINTER(vrf->rth, NULL);
+ RCU_INIT_POINTER(vrf->rth_local, NULL);
+ synchronize_rcu();
if (rth)
dst_release(&rth->dst);
+
+ if (rth_local)
+ dst_release(&rth_local->dst);
}
static int vrf_rtable_create(struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
- struct rtable *rth;
+ struct rtable *rth, *rth_local;
if (!fib_new_table(dev_net(dev), vrf->tb_id))
return -ENOMEM;
+ /* create a dst for routing packets out through a VRF device */
rth = rt_dst_alloc(dev, 0, RTN_UNICAST, 1, 1, 0);
if (!rth)
return -ENOMEM;
+ /* create a dst for local ingress routing - packets sent locally
+ * to local address via the VRF device as a loopback
+ */
+ rth_local = rt_dst_alloc(dev, RTCF_LOCAL, RTN_LOCAL, 1, 1, 0);
+ if (!rth_local) {
+ dst_release(&rth->dst);
+ return -ENOMEM;
+ }
+
rth->dst.output = vrf_output;
rth->rt_table_id = vrf->tb_id;
+ rth_local->rt_table_id = vrf->tb_id;
+
rcu_assign_pointer(vrf->rth, rth);
+ rcu_assign_pointer(vrf->rth_local, rth_local);
return 0;
}
@@ -652,10 +739,19 @@ static struct sk_buff *vrf_ip_rcv(struct net_device
*vrf_dev,
skb->dev = vrf_dev;
skb->skb_iif = vrf_dev->ifindex;
+ /* loopback traffic; do not push through packet taps again.
+ * Reset pkt_type for upper layers to process skb
+ */
+ if (skb->pkt_type == PACKET_LOOPBACK) {
+ skb->pkt_type = PACKET_HOST;
+ goto out;
+ }
+
skb_push(skb, skb->mac_len);
dev_queue_xmit_nit(skb, vrf_dev);
skb_pull(skb, skb->mac_len);
+out:
return skb;
}
--
2.1.4
