bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports
authorRoopa Prabhu <roopa@cumulusnetworks.com>
Sat, 7 Oct 2017 05:12:39 +0000 (22:12 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 9 Oct 2017 04:12:04 +0000 (21:12 -0700)
This patch avoids flooding and proxies ndisc packets
for BR_NEIGH_SUPPRESS ports.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/bridge/br_arp_nd_proxy.c
net/bridge/br_device.c
net/bridge/br_input.c
net/bridge/br_private.h

index a79c182..2cf7716 100644 (file)
@@ -21,6 +21,9 @@
 #include <linux/if_vlan.h>
 #include <linux/inetdevice.h>
 #include <net/addrconf.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ip6_checksum.h>
+#endif
 
 #include "br_private.h"
 
@@ -218,3 +221,249 @@ void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
        }
 }
 #endif
+
+#if IS_ENABLED(CONFIG_IPV6)
+struct nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *msg)
+{
+       struct nd_msg *m;
+
+       m = skb_header_pointer(skb, skb_network_offset(skb) +
+                              sizeof(struct ipv6hdr), sizeof(*msg), msg);
+       if (!m)
+               return NULL;
+
+       if (m->icmph.icmp6_code != 0 ||
+           (m->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION &&
+            m->icmph.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT))
+               return NULL;
+
+       return m;
+}
+
+static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p,
+                      struct sk_buff *request, struct neighbour *n,
+                      __be16 vlan_proto, u16 vlan_tci, struct nd_msg *ns)
+{
+       struct net_device *dev = request->dev;
+       struct net_bridge_vlan_group *vg;
+       struct sk_buff *reply;
+       struct nd_msg *na;
+       struct ipv6hdr *pip6;
+       int na_olen = 8; /* opt hdr + ETH_ALEN for target */
+       int ns_olen;
+       int i, len;
+       u8 *daddr;
+       u16 pvid;
+
+       if (!dev)
+               return;
+
+       len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) +
+               sizeof(*na) + na_olen + dev->needed_tailroom;
+
+       reply = alloc_skb(len, GFP_ATOMIC);
+       if (!reply)
+               return;
+
+       reply->protocol = htons(ETH_P_IPV6);
+       reply->dev = dev;
+       skb_reserve(reply, LL_RESERVED_SPACE(dev));
+       skb_push(reply, sizeof(struct ethhdr));
+       skb_set_mac_header(reply, 0);
+
+       daddr = eth_hdr(request)->h_source;
+
+       /* Do we need option processing ? */
+       ns_olen = request->len - (skb_network_offset(request) +
+                                 sizeof(struct ipv6hdr)) - sizeof(*ns);
+       for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) {
+               if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
+                       daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
+                       break;
+               }
+       }
+
+       /* Ethernet header */
+       ether_addr_copy(eth_hdr(reply)->h_dest, daddr);
+       ether_addr_copy(eth_hdr(reply)->h_source, n->ha);
+       eth_hdr(reply)->h_proto = htons(ETH_P_IPV6);
+       reply->protocol = htons(ETH_P_IPV6);
+
+       skb_pull(reply, sizeof(struct ethhdr));
+       skb_set_network_header(reply, 0);
+       skb_put(reply, sizeof(struct ipv6hdr));
+
+       /* IPv6 header */
+       pip6 = ipv6_hdr(reply);
+       memset(pip6, 0, sizeof(struct ipv6hdr));
+       pip6->version = 6;
+       pip6->priority = ipv6_hdr(request)->priority;
+       pip6->nexthdr = IPPROTO_ICMPV6;
+       pip6->hop_limit = 255;
+       pip6->daddr = ipv6_hdr(request)->saddr;
+       pip6->saddr = *(struct in6_addr *)n->primary_key;
+
+       skb_pull(reply, sizeof(struct ipv6hdr));
+       skb_set_transport_header(reply, 0);
+
+       na = (struct nd_msg *)skb_put(reply, sizeof(*na) + na_olen);
+
+       /* Neighbor Advertisement */
+       memset(na, 0, sizeof(*na) + na_olen);
+       na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
+       na->icmph.icmp6_router = 0; /* XXX: should be 1 ? */
+       na->icmph.icmp6_override = 1;
+       na->icmph.icmp6_solicited = 1;
+       na->target = ns->target;
+       ether_addr_copy(&na->opt[2], n->ha);
+       na->opt[0] = ND_OPT_TARGET_LL_ADDR;
+       na->opt[1] = na_olen >> 3;
+
+       na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr,
+                                               &pip6->daddr,
+                                               sizeof(*na) + na_olen,
+                                               IPPROTO_ICMPV6,
+                                               csum_partial(na, sizeof(*na) + na_olen, 0));
+
+       pip6->payload_len = htons(sizeof(*na) + na_olen);
+
+       skb_push(reply, sizeof(struct ipv6hdr));
+       skb_push(reply, sizeof(struct ethhdr));
+
+       reply->ip_summed = CHECKSUM_UNNECESSARY;
+
+       if (p)
+               vg = nbp_vlan_group_rcu(p);
+       else
+               vg = br_vlan_group_rcu(br);
+       pvid = br_get_pvid(vg);
+       if (pvid == (vlan_tci & VLAN_VID_MASK))
+               vlan_tci = 0;
+
+       if (vlan_tci)
+               __vlan_hwaccel_put_tag(reply, vlan_proto, vlan_tci);
+
+       netdev_dbg(dev, "nd send dev %s dst %pI6 dst_hw %pM src %pI6 src_hw %pM\n",
+                  dev->name, &pip6->daddr, daddr, &pip6->saddr, n->ha);
+
+       if (p) {
+               dev_queue_xmit(reply);
+       } else {
+               skb_reset_mac_header(reply);
+               __skb_pull(reply, skb_network_offset(reply));
+               reply->ip_summed = CHECKSUM_UNNECESSARY;
+               reply->pkt_type = PACKET_HOST;
+
+               netif_rx_ni(reply);
+       }
+}
+
+static int br_chk_addr_ip6(struct net_device *dev, void *data)
+{
+       struct in6_addr *addr = (struct in6_addr *)data;
+
+       if (ipv6_chk_addr(dev_net(dev), addr, dev, 0))
+               return 1;
+
+       return 0;
+}
+
+static bool br_is_local_ip6(struct net_device *dev, struct in6_addr *addr)
+
+{
+       if (br_chk_addr_ip6(dev, addr))
+               return true;
+
+       /* check if ip is configured on upper dev */
+       if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, addr))
+               return true;
+
+       return false;
+}
+
+void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br,
+                      u16 vid, struct net_bridge_port *p, struct nd_msg *msg)
+{
+       struct net_device *dev = br->dev;
+       struct net_device *vlandev = NULL;
+       struct in6_addr *saddr, *daddr;
+       struct ipv6hdr *iphdr;
+       struct neighbour *n;
+
+       BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
+
+       if (p && (p->flags & BR_NEIGH_SUPPRESS))
+               return;
+
+       if (msg->icmph.icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT &&
+           !msg->icmph.icmp6_solicited) {
+               /* prevent flooding to neigh suppress ports */
+               BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
+               return;
+       }
+
+       if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
+               return;
+
+       iphdr = ipv6_hdr(skb);
+       saddr = &iphdr->saddr;
+       daddr = &iphdr->daddr;
+
+       if (ipv6_addr_any(saddr) || !ipv6_addr_cmp(saddr, daddr)) {
+               /* prevent flooding to neigh suppress ports */
+               BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
+               return;
+       }
+
+       if (vid != 0) {
+               /* build neigh table lookup on the vlan device */
+               vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
+                                                  vid);
+               if (!vlandev)
+                       return;
+       } else {
+               vlandev = dev;
+       }
+
+       if (br_is_local_ip6(vlandev, &msg->target)) {
+               /* its our own ip, so don't proxy reply
+                * and don't forward to arp suppress ports
+                */
+               BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
+               return;
+       }
+
+       n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev);
+       if (n) {
+               struct net_bridge_fdb_entry *f;
+
+               if (!(n->nud_state & NUD_VALID)) {
+                       neigh_release(n);
+                       return;
+               }
+
+               f = br_fdb_find_rcu(br, n->ha, vid);
+               if (f) {
+                       bool replied = false;
+
+                       if (f->dst && (f->dst->flags & BR_NEIGH_SUPPRESS)) {
+                               if (vid != 0)
+                                       br_nd_send(br, p, skb, n,
+                                                  skb->vlan_proto,
+                                                  skb_vlan_tag_get(skb), msg);
+                               else
+                                       br_nd_send(br, p, skb, n, 0, 0, msg);
+                               replied = true;
+                       }
+
+                       /* If we have replied or as long as we know the
+                        * mac, indicate to NEIGH_SUPPRESS ports that we
+                        * have replied
+                        */
+                       if (replied || br->neigh_suppress_enabled)
+                               BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
+               }
+               neigh_release(n);
+       }
+}
+#endif
index eb30c6a..28bb221 100644 (file)
@@ -69,6 +69,17 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
             eth->h_proto == htons(ETH_P_RARP)) &&
            br->neigh_suppress_enabled) {
                br_do_proxy_suppress_arp(skb, br, vid, NULL);
+       } else if (IS_ENABLED(CONFIG_IPV6) &&
+                  skb->protocol == htons(ETH_P_IPV6) &&
+                  br->neigh_suppress_enabled &&
+                  pskb_may_pull(skb, sizeof(struct ipv6hdr) +
+                                sizeof(struct nd_msg)) &&
+                  ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
+                       struct nd_msg *msg, _msg;
+
+                       msg = br_is_nd_neigh_msg(skb, &_msg);
+                       if (msg)
+                               br_do_suppress_nd(skb, br, vid, NULL, msg);
        }
 
        dest = eth_hdr(skb)->h_dest;
index 4b8d2ec..a096d3e 100644 (file)
@@ -119,6 +119,17 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
            (skb->protocol == htons(ETH_P_ARP) ||
             skb->protocol == htons(ETH_P_RARP))) {
                br_do_proxy_suppress_arp(skb, br, vid, p);
+       } else if (IS_ENABLED(CONFIG_IPV6) &&
+                  skb->protocol == htons(ETH_P_IPV6) &&
+                  br->neigh_suppress_enabled &&
+                  pskb_may_pull(skb, sizeof(struct ipv6hdr) +
+                                sizeof(struct nd_msg)) &&
+                  ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
+                       struct nd_msg *msg, _msg;
+
+                       msg = br_is_nd_neigh_msg(skb, &_msg);
+                       if (msg)
+                               br_do_suppress_nd(skb, br, vid, p, msg);
        }
 
        switch (pkt_type) {
index 4e6b25b..fa0039f 100644 (file)
@@ -1144,4 +1144,7 @@ static inline void br_switchdev_frame_unmark(struct sk_buff *skb)
 void br_recalculate_neigh_suppress_enabled(struct net_bridge *br);
 void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
                              u16 vid, struct net_bridge_port *p);
+void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br,
+                      u16 vid, struct net_bridge_port *p, struct nd_msg *msg);
+struct nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *m);
 #endif