From 671cd19ade97e98046d0b0d1d470d4968f012401 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 2 Jun 2016 13:15:11 -0700 Subject: [PATCH] net: vrf: ipv4 support for local traffic to local addresses 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: 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 Signed-off-by: David S. Miller --- 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; } -- 2.20.1