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/*
* 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>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#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 "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->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 = false;
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->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 = true;
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->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 = true;
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->neigh_suppress_enabled)
BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
}
neigh_release(n);
}
}
#endif
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