linux/net/bridge/br_arp_nd_proxy.c

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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 <roopa@cumulusnetworks.com>
*
* Authors:
* Roopa Prabhu <roopa@cumulusnetworks.com>
*/
#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_ni(skb);
}
}
static int br_chk_addr_ip(struct net_device *dev, void *data)
{
__be32 ip = *(__be32 *)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)
{
if (br_chk_addr_ip(dev, &ip))
return true;
/* check if ip is configured on upper dev */
if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &ip))
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 (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 (!(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_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 = 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 (!(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