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Message-Id: <1465271440-31389-4-git-send-email-dsa@cumulusnetworks.com>
Date: Mon, 6 Jun 2016 20:50:40 -0700
From: David Ahern <dsa@...ulusnetworks.com>
To: netdev@...r.kernel.org
Cc: David Ahern <dsa@...ulusnetworks.com>
Subject: [PATCH net-next v2 3/3] net: vrf: ipv6 support for local traffic to local addresses
Add support for locally originated traffic to VRF-local IPv6 addresses.
Similar to IPv4 a local dst is set on the skb and the packet is
reinserted with a call to netif_rx. With this patch, ping, tcp and udp
packets to a local IPv6 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
$ ping6 -c1 -I red 2100:1::1
ping6: Warning: source address might be selected on device other than red.
PING 2100:1::1(2100:1::1) from 2100:1::1 red: 56 data bytes
64 bytes from 2100:1::1: icmp_seq=1 ttl=64 time=0.098 ms
ip6_input is exported so the VRF driver can use it for the dst input
function. The dst_alloc function for IPv4 defaults to setting the input and
output functions; IPv6's does not. VRF does not need to duplicate the Rx path
so just export the ipv6 input function.
Signed-off-by: David Ahern <dsa@...ulusnetworks.com>
---
v2
- add export of ip6_input
drivers/net/vrf.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++---
net/ipv6/ip6_input.c | 1 +
2 files changed, 86 insertions(+), 4 deletions(-)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 203d3c78a6e5..1b214ea4619a 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -46,6 +46,7 @@ struct net_vrf {
struct rtable __rcu *rth;
struct rtable __rcu *rth_local;
struct rt6_info __rcu *rt6;
+ struct rt6_info __rcu *rt6_local;
u32 tb_id;
};
@@ -157,6 +158,46 @@ static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
goto err;
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 (dst->dev == net->loopback_dev || dst->dev == dev) {
+ struct net_vrf *vrf = netdev_priv(dev);
+ struct rt6_info *rt6_local;
+
+ /* release looked up dst and use cached local dst */
+ dst_release(dst);
+
+ rcu_read_lock();
+
+ rt6_local = rcu_dereference(vrf->rt6_local);
+ if (unlikely(!rt6_local)) {
+ rcu_read_unlock();
+ goto err;
+ }
+
+ /* Ordering issue: cached local dst is created on newlink
+ * before the IPv6 initialization. Using the local dst
+ * requires rt6i_idev to be set so make sure it is.
+ */
+ if (unlikely(!rt6_local->rt6i_idev)) {
+ rt6_local->rt6i_idev = in6_dev_get(dev);
+ if (!rt6_local->rt6i_idev) {
+ rcu_read_unlock();
+ goto err;
+ }
+ }
+
+ dst = &rt6_local->dst;
+ dst_hold(dst);
+
+ rcu_read_unlock();
+
+ return vrf_local_xmit(skb, dev, &rt6_local->dst);
+ }
+
skb_dst_set(skb, dst);
/* strip the ethernet header added for pass through VRF device */
@@ -336,27 +377,38 @@ static int vrf_output6(struct net *net, struct sock *sk, struct sk_buff *skb)
static void vrf_rt6_release(struct net_vrf *vrf)
{
struct rt6_info *rt6 = rtnl_dereference(vrf->rt6);
+ struct rt6_info *rt6_local = rtnl_dereference(vrf->rt6_local);
- rcu_assign_pointer(vrf->rt6, NULL);
+ RCU_INIT_POINTER(vrf->rt6, NULL);
+ RCU_INIT_POINTER(vrf->rt6_local, NULL);
+ synchronize_rcu();
if (rt6)
dst_release(&rt6->dst);
+
+ if (rt6_local) {
+ if (rt6_local->rt6i_idev)
+ in6_dev_put(rt6_local->rt6i_idev);
+
+ dst_release(&rt6_local->dst);
+ }
}
static int vrf_rt6_create(struct net_device *dev)
{
+ int flags = DST_HOST | DST_NOPOLICY | DST_NOXFRM | DST_NOCACHE;
struct net_vrf *vrf = netdev_priv(dev);
struct net *net = dev_net(dev);
struct fib6_table *rt6i_table;
- struct rt6_info *rt6;
+ struct rt6_info *rt6, *rt6_local;
int rc = -ENOMEM;
rt6i_table = fib6_new_table(net, vrf->tb_id);
if (!rt6i_table)
goto out;
- rt6 = ip6_dst_alloc(net, dev,
- DST_HOST | DST_NOPOLICY | DST_NOXFRM | DST_NOCACHE);
+ /* create a dst for routing packets out a VRF device */
+ rt6 = ip6_dst_alloc(net, dev, flags);
if (!rt6)
goto out;
@@ -364,7 +416,25 @@ static int vrf_rt6_create(struct net_device *dev)
rt6->rt6i_table = rt6i_table;
rt6->dst.output = vrf_output6;
+
+ /* create a dst for local routing - packets sent locally
+ * to local address via the VRF device as a loopback
+ */
+ rt6_local = ip6_dst_alloc(net, dev, flags);
+ if (!rt6_local) {
+ dst_release(&rt6->dst);
+ goto out;
+ }
+
+ dst_hold(&rt6_local->dst);
+
+ rt6_local->rt6i_idev = in6_dev_get(dev);
+ rt6_local->rt6i_flags = RTF_UP | RTF_NONEXTHOP | RTF_LOCAL;
+ rt6_local->rt6i_table = rt6i_table;
+ rt6_local->dst.input = ip6_input;
+
rcu_assign_pointer(vrf->rt6, rt6);
+ rcu_assign_pointer(vrf->rt6_local, rt6_local);
rc = 0;
out:
@@ -710,6 +780,16 @@ static bool ipv6_ndisc_frame(const struct sk_buff *skb)
static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
struct sk_buff *skb)
{
+ /* 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->dev = vrf_dev;
+ skb->skb_iif = vrf_dev->ifindex;
+ skb->pkt_type = PACKET_HOST;
+ goto out;
+ }
+
/* if packet is NDISC keep the ingress interface */
if (!ipv6_ndisc_frame(skb)) {
skb->dev = vrf_dev;
@@ -722,6 +802,7 @@ static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
IP6CB(skb)->flags |= IP6SKB_L3SLAVE;
}
+out:
return skb;
}
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 94611e450ec9..aacfb4bce153 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -323,6 +323,7 @@ int ip6_input(struct sk_buff *skb)
dev_net(skb->dev), NULL, skb, skb->dev, NULL,
ip6_input_finish);
}
+EXPORT_SYMBOL_GPL(ip6_input);
int ip6_mc_input(struct sk_buff *skb)
{
--
2.1.4
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