linux/net/bridge/br_arp_nd_proxy.c
Nikolay Aleksandrov 0353b4a96b net: bridge: when suppression is enabled exclude RARP packets
Recently we had an interop issue where RARP packets got suppressed with
bridge neigh suppression enabled, but the check in the code was meant to
suppress GARP. Exclude RARP packets from it which would allow some VMWare
setups to work, to quote the report:
"Those RARP packets usually get generated by vMware to notify physical
switches when vMotion occurs. vMware may use random sip/tip or just use
sip=tip=0. So the RARP packet sometimes get properly flooded by the vtep
and other times get dropped by the logic"

Reported-by: Amer Abdalamer <amer@nvidia.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-22 13:30:24 -07:00

486 lines
11 KiB
C

// 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,
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 (!(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,
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 (!(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