net: Add IPv6 support to VRF device

Add support for IPv6 to VRF device driver. Implemenation parallels what
has been done for IPv4.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index b9ebd0d..f184fb5 100644 (file)
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -298,8 +298,10 @@ config NLMON
 
 config NET_VRF
        tristate "Virtual Routing and Forwarding (Lite)"
-       depends on IP_MULTIPLE_TABLES && IPV6_MULTIPLE_TABLES
+       depends on IP_MULTIPLE_TABLES
        depends on NET_L3_MASTER_DEV
+       depends on IPV6 || IPV6=n
+       depends on IPV6_MULTIPLE_TABLES || IPV6=n
        ---help---
          This option enables the support for mapping interfaces into VRF's. The
          support enables VRF devices.

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 191579a..92fa3e1 100644 (file)
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -30,6 +30,7 @@
 #include <net/arp.h>
 #include <net/ip.h>
 #include <net/ip_fib.h>
+#include <net/ip6_fib.h>
 #include <net/ip6_route.h>
 #include <net/rtnetlink.h>
 #include <net/route.h>
@@ -57,6 +58,7 @@ struct slave_queue {
 struct net_vrf {
        struct slave_queue      queue;
        struct rtable           *rth;
+       struct rt6_info         *rt6;
        u32                     tb_id;
 };
 
@@ -104,12 +106,56 @@ static struct dst_ops vrf_dst_ops = {
        .default_advmss = vrf_default_advmss,
 };
 
+/* neighbor handling is done with actual device; do not want
+ * to flip skb->dev for those ndisc packets. This really fails
+ * for multiple next protocols (e.g., NEXTHDR_HOP). But it is
+ * a start.
+ */
+#if IS_ENABLED(CONFIG_IPV6)
+static bool check_ipv6_frame(const struct sk_buff *skb)
+{
+       const struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb->data;
+       size_t hlen = sizeof(*ipv6h);
+       bool rc = true;
+
+       if (skb->len < hlen)
+               goto out;
+
+       if (ipv6h->nexthdr == NEXTHDR_ICMP) {
+               const struct icmp6hdr *icmph;
+
+               if (skb->len < hlen + sizeof(*icmph))
+                       goto out;
+
+               icmph = (struct icmp6hdr *)(skb->data + sizeof(*ipv6h));
+               switch (icmph->icmp6_type) {
+               case NDISC_ROUTER_SOLICITATION:
+               case NDISC_ROUTER_ADVERTISEMENT:
+               case NDISC_NEIGHBOUR_SOLICITATION:
+               case NDISC_NEIGHBOUR_ADVERTISEMENT:
+               case NDISC_REDIRECT:
+                       rc = false;
+                       break;
+               }
+       }
+
+out:
+       return rc;
+}
+#else
+static bool check_ipv6_frame(const struct sk_buff *skb)
+{
+       return false;
+}
+#endif
+
 static bool is_ip_rx_frame(struct sk_buff *skb)
 {
        switch (skb->protocol) {
        case htons(ETH_P_IP):
-       case htons(ETH_P_IPV6):
                return true;
+       case htons(ETH_P_IPV6):
+               return check_ipv6_frame(skb);
        }
        return false;
 }
@@ -169,12 +215,53 @@ static struct rtnl_link_stats64 *vrf_get_stats64(struct net_device *dev,
        return stats;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
+static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
+                                          struct net_device *dev)
+{
+       const struct ipv6hdr *iph = ipv6_hdr(skb);
+       struct net *net = dev_net(skb->dev);
+       struct flowi6 fl6 = {
+               /* needed to match OIF rule */
+               .flowi6_oif = dev->ifindex,
+               .flowi6_iif = LOOPBACK_IFINDEX,
+               .daddr = iph->daddr,
+               .saddr = iph->saddr,
+               .flowlabel = ip6_flowinfo(iph),
+               .flowi6_mark = skb->mark,
+               .flowi6_proto = iph->nexthdr,
+               .flowi6_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF,
+       };
+       int ret = NET_XMIT_DROP;
+       struct dst_entry *dst;
+       struct dst_entry *dst_null = &net->ipv6.ip6_null_entry->dst;
+
+       dst = ip6_route_output(net, NULL, &fl6);
+       if (dst == dst_null)
+               goto err;
+
+       skb_dst_drop(skb);
+       skb_dst_set(skb, dst);
+
+       ret = ip6_local_out(net, skb->sk, skb);
+       if (unlikely(net_xmit_eval(ret)))
+               dev->stats.tx_errors++;
+       else
+               ret = NET_XMIT_SUCCESS;
+
+       return ret;
+err:
+       vrf_tx_error(dev, skb);
+       return NET_XMIT_DROP;
+}
+#else
 static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
                                           struct net_device *dev)
 {
        vrf_tx_error(dev, skb);
        return NET_XMIT_DROP;
 }
+#endif
 
 static int vrf_send_v4_prep(struct sk_buff *skb, struct flowi4 *fl4,
                            struct net_device *vrf_dev)
@@ -269,6 +356,157 @@ static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
        return ret;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
+static struct dst_entry *vrf_ip6_check(struct dst_entry *dst, u32 cookie)
+{
+       return dst;
+}
+
+static struct dst_ops vrf_dst_ops6 = {
+       .family         = AF_INET6,
+       .local_out      = ip6_local_out,
+       .check          = vrf_ip6_check,
+       .mtu            = vrf_v4_mtu,
+       .destroy        = vrf_dst_destroy,
+       .default_advmss = vrf_default_advmss,
+};
+
+static int init_dst_ops6_kmem_cachep(void)
+{
+       vrf_dst_ops6.kmem_cachep = kmem_cache_create("vrf_ip6_dst_cache",
+                                                    sizeof(struct rt6_info),
+                                                    0,
+                                                    SLAB_HWCACHE_ALIGN,
+                                                    NULL);
+
+       if (!vrf_dst_ops6.kmem_cachep)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void free_dst_ops6_kmem_cachep(void)
+{
+       kmem_cache_destroy(vrf_dst_ops6.kmem_cachep);
+}
+
+static int vrf_input6(struct sk_buff *skb)
+{
+       skb->dev->stats.rx_errors++;
+       kfree_skb(skb);
+       return 0;
+}
+
+/* modelled after ip6_finish_output2 */
+static int vrf_finish_output6(struct net *net, struct sock *sk,
+                             struct sk_buff *skb)
+{
+       struct dst_entry *dst = skb_dst(skb);
+       struct net_device *dev = dst->dev;
+       struct neighbour *neigh;
+       struct in6_addr *nexthop;
+       int ret;
+
+       skb->protocol = htons(ETH_P_IPV6);
+       skb->dev = dev;
+
+       rcu_read_lock_bh();
+       nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
+       neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
+       if (unlikely(!neigh))
+               neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
+       if (!IS_ERR(neigh)) {
+               ret = dst_neigh_output(dst, neigh, skb);
+               rcu_read_unlock_bh();
+               return ret;
+       }
+       rcu_read_unlock_bh();
+
+       IP6_INC_STATS(dev_net(dst->dev),
+                     ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
+       kfree_skb(skb);
+       return -EINVAL;
+}
+
+/* modelled after ip6_output */
+static int vrf_output6(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+       return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
+                           net, sk, skb, NULL, skb_dst(skb)->dev,
+                           vrf_finish_output6,
+                           !(IP6CB(skb)->flags & IP6SKB_REROUTED));
+}
+
+static void vrf_rt6_destroy(struct net_vrf *vrf)
+{
+       dst_destroy(&vrf->rt6->dst);
+       free_percpu(vrf->rt6->rt6i_pcpu);
+       vrf->rt6 = NULL;
+}
+
+static int vrf_rt6_create(struct net_device *dev)
+{
+       struct net_vrf *vrf = netdev_priv(dev);
+       struct dst_entry *dst;
+       struct rt6_info *rt6;
+       int cpu;
+       int rc = -ENOMEM;
+
+       rt6 = dst_alloc(&vrf_dst_ops6, dev, 0,
+                       DST_OBSOLETE_NONE,
+                       (DST_HOST | DST_NOPOLICY | DST_NOXFRM));
+       if (!rt6)
+               goto out;
+
+       dst = &rt6->dst;
+
+       rt6->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, GFP_KERNEL);
+       if (!rt6->rt6i_pcpu) {
+               dst_destroy(dst);
+               goto out;
+       }
+       for_each_possible_cpu(cpu) {
+               struct rt6_info **p = per_cpu_ptr(rt6->rt6i_pcpu, cpu);
+               *p =  NULL;
+       }
+
+       memset(dst + 1, 0, sizeof(*rt6) - sizeof(*dst));
+
+       INIT_LIST_HEAD(&rt6->rt6i_siblings);
+       INIT_LIST_HEAD(&rt6->rt6i_uncached);
+
+       rt6->dst.input  = vrf_input6;
+       rt6->dst.output = vrf_output6;
+
+       rt6->rt6i_table = fib6_get_table(dev_net(dev), vrf->tb_id);
+
+       atomic_set(&rt6->dst.__refcnt, 2);
+
+       vrf->rt6 = rt6;
+       rc = 0;
+out:
+       return rc;
+}
+#else
+static int init_dst_ops6_kmem_cachep(void)
+{
+       return 0;
+}
+
+static void free_dst_ops6_kmem_cachep(void)
+{
+}
+
+static void vrf_rt6_destroy(struct net_vrf *vrf)
+{
+}
+
+static int vrf_rt6_create(struct net_device *dev)
+{
+       return 0;
+}
+#endif
+
 /* modelled after ip_finish_output2 */
 static int vrf_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
@@ -490,6 +728,7 @@ static void vrf_dev_uninit(struct net_device *dev)
        struct slave *slave, *next;
 
        vrf_rtable_destroy(vrf);
+       vrf_rt6_destroy(vrf);
 
        list_for_each_entry_safe(slave, next, head, list)
                vrf_del_slave(dev, slave->dev);
@@ -513,10 +752,15 @@ static int vrf_dev_init(struct net_device *dev)
        if (!vrf->rth)
                goto out_stats;
 
+       if (vrf_rt6_create(dev) != 0)
+               goto out_rth;
+
        dev->flags = IFF_MASTER | IFF_NOARP;
 
        return 0;
 
+out_rth:
+       vrf_rtable_destroy(vrf);
 out_stats:
        free_percpu(dev->dstats);
        dev->dstats = NULL;
@@ -586,10 +830,30 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
        fl4->flowi4_scope = scope;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
+static struct dst_entry *vrf_get_rt6_dst(const struct net_device *dev,
+                                        const struct flowi6 *fl6)
+{
+       struct rt6_info *rt = NULL;
+
+       if (!(fl6->flowi6_flags & FLOWI_FLAG_L3MDEV_SRC)) {
+               struct net_vrf *vrf = netdev_priv(dev);
+
+               rt = vrf->rt6;
+               atomic_inc(&rt->dst.__refcnt);
+       }
+
+       return (struct dst_entry *)rt;
+}
+#endif
+
 static const struct l3mdev_ops vrf_l3mdev_ops = {
        .l3mdev_fib_table       = vrf_fib_table,
        .l3mdev_get_rtable      = vrf_get_rtable,
        .l3mdev_get_saddr       = vrf_get_saddr,
+#if IS_ENABLED(CONFIG_IPV6)
+       .l3mdev_get_rt6_dst     = vrf_get_rt6_dst,
+#endif
 };
 
 static void vrf_get_drvinfo(struct net_device *dev,
@@ -731,6 +995,10 @@ static int __init vrf_init_module(void)
        if (!vrf_dst_ops.kmem_cachep)
                return -ENOMEM;
 
+       rc = init_dst_ops6_kmem_cachep();
+       if (rc != 0)
+               goto error2;
+
        register_netdevice_notifier(&vrf_notifier_block);
 
        rc = rtnl_link_register(&vrf_link_ops);
@@ -741,6 +1009,8 @@ static int __init vrf_init_module(void)
 
 error:
        unregister_netdevice_notifier(&vrf_notifier_block);
+       free_dst_ops6_kmem_cachep();
+error2:
        kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
        return rc;
 }
@@ -750,6 +1020,7 @@ static void __exit vrf_cleanup_module(void)
        rtnl_link_unregister(&vrf_link_ops);
        unregister_netdevice_notifier(&vrf_notifier_block);
        kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
+       free_dst_ops6_kmem_cachep();
 }
 
 module_init(vrf_init_module);