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net: vrf: ipv4 support for local traffic to local addresses

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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 <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2016-06-06 20:50:39 -07:00 committed by David S. Miller
parent 911a66fbc8
commit afe80a4998
1 changed files with 98 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

100
drivers/net/vrf.c
View File

@ -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;
}