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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * Handle bridge arp/nd proxy/suppress
- *
- * Copyright (C) 2017 Cumulus Networks
- * Copyright (c) 2017 Roopa Prabhu <[email protected]>
- *
- * Authors:
- * Roopa Prabhu <[email protected]>
- */
- #include <linux/kernel.h>
- #include <linux/netdevice.h>
- #include <linux/etherdevice.h>
- #include <linux/neighbour.h>
- #include <net/arp.h>
- #include <linux/if_vlan.h>
- #include <linux/inetdevice.h>
- #include <net/addrconf.h>
- #include <net/ipv6_stubs.h>
- #if IS_ENABLED(CONFIG_IPV6)
- #include <net/ip6_checksum.h>
- #endif
- #include "br_private.h"
- void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
- {
- struct net_bridge_port *p;
- bool neigh_suppress = false;
- list_for_each_entry(p, &br->port_list, list) {
- if (p->flags & BR_NEIGH_SUPPRESS) {
- neigh_suppress = true;
- break;
- }
- }
- br_opt_toggle(br, BROPT_NEIGH_SUPPRESS_ENABLED, neigh_suppress);
- }
- #if IS_ENABLED(CONFIG_INET)
- static void br_arp_send(struct net_bridge *br, struct net_bridge_port *p,
- struct net_device *dev, __be32 dest_ip, __be32 src_ip,
- const unsigned char *dest_hw,
- const unsigned char *src_hw,
- const unsigned char *target_hw,
- __be16 vlan_proto, u16 vlan_tci)
- {
- struct net_bridge_vlan_group *vg;
- struct sk_buff *skb;
- u16 pvid;
- netdev_dbg(dev, "arp send dev %s dst %pI4 dst_hw %pM src %pI4 src_hw %pM\n",
- dev->name, &dest_ip, dest_hw, &src_ip, src_hw);
- if (!vlan_tci) {
- arp_send(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
- dest_hw, src_hw, target_hw);
- return;
- }
- skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
- dest_hw, src_hw, target_hw);
- if (!skb)
- return;
- 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(skb, vlan_proto, vlan_tci);
- if (p) {
- arp_xmit(skb);
- } else {
- skb_reset_mac_header(skb);
- __skb_pull(skb, skb_network_offset(skb));
- skb->ip_summed = CHECKSUM_UNNECESSARY;
- skb->pkt_type = PACKET_HOST;
- netif_rx(skb);
- }
- }
- static int br_chk_addr_ip(struct net_device *dev,
- struct netdev_nested_priv *priv)
- {
- __be32 ip = *(__be32 *)priv->data;
- struct in_device *in_dev;
- __be32 addr = 0;
- in_dev = __in_dev_get_rcu(dev);
- if (in_dev)
- addr = inet_confirm_addr(dev_net(dev), in_dev, 0, ip,
- RT_SCOPE_HOST);
- if (addr == ip)
- return 1;
- return 0;
- }
- static bool br_is_local_ip(struct net_device *dev, __be32 ip)
- {
- struct netdev_nested_priv priv = {
- .data = (void *)&ip,
- };
- if (br_chk_addr_ip(dev, &priv))
- return true;
- /* check if ip is configured on upper dev */
- if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &priv))
- return true;
- return false;
- }
- void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
- u16 vid, struct net_bridge_port *p)
- {
- struct net_device *dev = br->dev;
- struct net_device *vlandev = dev;
- struct neighbour *n;
- struct arphdr *parp;
- u8 *arpptr, *sha;
- __be32 sip, tip;
- BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;
- if ((dev->flags & IFF_NOARP) ||
- !pskb_may_pull(skb, arp_hdr_len(dev)))
- return;
- parp = arp_hdr(skb);
- if (parp->ar_pro != htons(ETH_P_IP) ||
- parp->ar_hln != dev->addr_len ||
- parp->ar_pln != 4)
- return;
- arpptr = (u8 *)parp + sizeof(struct arphdr);
- sha = arpptr;
- arpptr += dev->addr_len; /* sha */
- memcpy(&sip, arpptr, sizeof(sip));
- arpptr += sizeof(sip);
- arpptr += dev->addr_len; /* tha */
- memcpy(&tip, arpptr, sizeof(tip));
- if (ipv4_is_loopback(tip) ||
- ipv4_is_multicast(tip))
- return;
- if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) {
- if (p && (p->flags & BR_NEIGH_SUPPRESS))
- return;
- if (parp->ar_op != htons(ARPOP_RREQUEST) &&
- parp->ar_op != htons(ARPOP_RREPLY) &&
- (ipv4_is_zeronet(sip) || sip == tip)) {
- /* prevent flooding to neigh suppress ports */
- BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
- return;
- }
- }
- if (parp->ar_op != htons(ARPOP_REQUEST))
- return;
- if (vid != 0) {
- vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
- vid);
- if (!vlandev)
- return;
- }
- if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
- br_is_local_ip(vlandev, tip)) {
- /* its our local ip, so don't proxy reply
- * and don't forward to neigh suppress ports
- */
- BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
- return;
- }
- n = neigh_lookup(&arp_tbl, &tip, vlandev);
- if (n) {
- struct net_bridge_fdb_entry *f;
- if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
- neigh_release(n);
- return;
- }
- f = br_fdb_find_rcu(br, n->ha, vid);
- if (f) {
- bool replied = false;
- if ((p && (p->flags & BR_PROXYARP)) ||
- (f->dst && (f->dst->flags & (BR_PROXYARP_WIFI |
- BR_NEIGH_SUPPRESS)))) {
- if (!vid)
- br_arp_send(br, p, skb->dev, sip, tip,
- sha, n->ha, sha, 0, 0);
- else
- br_arp_send(br, p, skb->dev, sip, tip,
- sha, n->ha, sha,
- skb->vlan_proto,
- skb_vlan_tag_get(skb));
- replied = true;
- }
- /* If we have replied or as long as we know the
- * mac, indicate to arp replied
- */
- if (replied ||
- br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
- BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
- }
- neigh_release(n);
- }
- }
- #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 + 1]) {
- kfree_skb(reply);
- return;
- }
- 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 = (n->flags & NTF_ROUTER) ? 1 : 0;
- 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(reply);
- }
- }
- static int br_chk_addr_ip6(struct net_device *dev,
- struct netdev_nested_priv *priv)
- {
- struct in6_addr *addr = (struct in6_addr *)priv->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)
- {
- struct netdev_nested_priv priv = {
- .data = (void *)addr,
- };
- if (br_chk_addr_ip6(dev, &priv))
- return true;
- /* check if ip is configured on upper dev */
- if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, &priv))
- 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 = 0;
- 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 = 1;
- 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 = 1;
- 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 = 1;
- return;
- }
- n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev);
- if (n) {
- struct net_bridge_fdb_entry *f;
- if (!(READ_ONCE(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_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
- BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
- }
- neigh_release(n);
- }
- }
- #endif
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