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Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02001/* linux/net/ipv4/arp.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090016 * Alan Cox : Removed the Ethernet assumptions in
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 * Florian's code
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090018 * Alan Cox : Fixed some small errors in the ARP
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090040 * Craig Schlenter : Don't modify permanent entry
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090044 * eg intelligent arp probing and
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090051 * Jonathan Layes : Added arpd support through kerneld
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
Changli Gaodeffd772010-09-02 03:56:51 +000058 * Alan Cox : Took the AP1000 nasty FDDI hack and
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
Jesper Dangaard Brouer65324142010-01-05 05:50:47 +000073 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 */
75
Joe Perches91df42b2012-05-15 14:11:54 +000076#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#include <linux/module.h>
79#include <linux/types.h>
80#include <linux/string.h>
81#include <linux/kernel.h>
Randy Dunlap4fc268d2006-01-11 12:17:47 -080082#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070083#include <linux/socket.h>
84#include <linux/sockios.h>
85#include <linux/errno.h>
86#include <linux/in.h>
87#include <linux/mm.h>
88#include <linux/inet.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020089#include <linux/inetdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070090#include <linux/netdevice.h>
91#include <linux/etherdevice.h>
92#include <linux/fddidevice.h>
93#include <linux/if_arp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070094#include <linux/skbuff.h>
95#include <linux/proc_fs.h>
96#include <linux/seq_file.h>
97#include <linux/stat.h>
98#include <linux/init.h>
99#include <linux/net.h>
100#include <linux/rcupdate.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +0900101#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102#ifdef CONFIG_SYSCTL
103#include <linux/sysctl.h>
104#endif
105
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200106#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107#include <net/ip.h>
108#include <net/icmp.h>
109#include <net/route.h>
110#include <net/protocol.h>
111#include <net/tcp.h>
112#include <net/sock.h>
113#include <net/arp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114#include <net/ax25.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115#include <net/netrom.h>
Jiri Benc63d008a2015-09-22 18:12:11 +0200116#include <net/dst_metadata.h>
117#include <net/ip_tunnels.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
Changli Gaodeffd772010-09-02 03:56:51 +0000119#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
121#include <linux/netfilter_arp.h>
122
123/*
124 * Interface to generic neighbour cache.
125 */
David S. Miller2c2aba62011-12-28 15:06:58 -0500126static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
Eric W. Biederman60395a22015-03-03 17:10:44 -0600127static bool arp_key_eq(const struct neighbour *n, const void *pkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128static int arp_constructor(struct neighbour *neigh);
129static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
130static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
131static void parp_redo(struct sk_buff *skb);
132
Stephen Hemminger89d69d22009-09-01 11:13:19 +0000133static const struct neigh_ops arp_generic_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 .family = AF_INET,
135 .solicit = arp_solicit,
136 .error_report = arp_error_report,
137 .output = neigh_resolve_output,
138 .connected_output = neigh_connected_output,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139};
140
Stephen Hemminger89d69d22009-09-01 11:13:19 +0000141static const struct neigh_ops arp_hh_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 .family = AF_INET,
143 .solicit = arp_solicit,
144 .error_report = arp_error_report,
145 .output = neigh_resolve_output,
146 .connected_output = neigh_resolve_output,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147};
148
Stephen Hemminger89d69d22009-09-01 11:13:19 +0000149static const struct neigh_ops arp_direct_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 .family = AF_INET,
David S. Miller8f40b162011-07-17 13:34:11 -0700151 .output = neigh_direct_output,
152 .connected_output = neigh_direct_output,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153};
154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155struct neigh_table arp_tbl = {
Changli Gaodeffd772010-09-02 03:56:51 +0000156 .family = AF_INET,
Changli Gaodeffd772010-09-02 03:56:51 +0000157 .key_len = 4,
Eric W. Biedermanbdf53c52015-03-02 00:13:22 -0600158 .protocol = cpu_to_be16(ETH_P_IP),
Changli Gaodeffd772010-09-02 03:56:51 +0000159 .hash = arp_hash,
Eric W. Biederman60395a22015-03-03 17:10:44 -0600160 .key_eq = arp_key_eq,
Changli Gaodeffd772010-09-02 03:56:51 +0000161 .constructor = arp_constructor,
162 .proxy_redo = parp_redo,
163 .id = "arp_cache",
164 .parms = {
165 .tbl = &arp_tbl,
Changli Gaodeffd772010-09-02 03:56:51 +0000166 .reachable_time = 30 * HZ,
Jiri Pirko1f9248e2013-12-07 19:26:53 +0100167 .data = {
168 [NEIGH_VAR_MCAST_PROBES] = 3,
169 [NEIGH_VAR_UCAST_PROBES] = 3,
170 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
171 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
172 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
173 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
174 [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
175 [NEIGH_VAR_PROXY_QLEN] = 64,
176 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
177 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
178 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
179 },
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 },
Changli Gaodeffd772010-09-02 03:56:51 +0000181 .gc_interval = 30 * HZ,
182 .gc_thresh1 = 128,
183 .gc_thresh2 = 512,
184 .gc_thresh3 = 1024,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185};
Eric Dumazet4bc2f182010-07-09 21:22:10 +0000186EXPORT_SYMBOL(arp_tbl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Al Viro714e85b2006-11-14 20:51:49 -0800188int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189{
190 switch (dev->type) {
191 case ARPHRD_ETHER:
192 case ARPHRD_FDDI:
193 case ARPHRD_IEEE802:
194 ip_eth_mc_map(addr, haddr);
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900195 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 case ARPHRD_INFINIBAND:
Rolf Manderscheida9e527e2007-12-10 13:38:41 -0700197 ip_ib_mc_map(addr, dev->broadcast, haddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 return 0;
Timo Teräs93ca3bb2011-03-28 22:40:53 +0000199 case ARPHRD_IPGRE:
200 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
201 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 default:
203 if (dir) {
204 memcpy(haddr, dev->broadcast, dev->addr_len);
205 return 0;
206 }
207 }
208 return -EINVAL;
209}
210
211
Eric Dumazetd6bf7812010-10-04 06:15:44 +0000212static u32 arp_hash(const void *pkey,
213 const struct net_device *dev,
David S. Miller2c2aba62011-12-28 15:06:58 -0500214 __u32 *hash_rnd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215{
Eric W. Biederman60395a22015-03-03 17:10:44 -0600216 return arp_hashfn(pkey, dev, hash_rnd);
217}
218
219static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
220{
221 return neigh_key_eq32(neigh, pkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222}
223
224static int arp_constructor(struct neighbour *neigh)
225{
Changli Gaodeffd772010-09-02 03:56:51 +0000226 __be32 addr = *(__be32 *)neigh->primary_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 struct net_device *dev = neigh->dev;
228 struct in_device *in_dev;
229 struct neigh_parms *parms;
230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 rcu_read_lock();
Herbert Xue5ed6392005-10-03 14:35:55 -0700232 in_dev = __in_dev_get_rcu(dev);
Ian Morris51456b22015-04-03 09:17:26 +0100233 if (!in_dev) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 rcu_read_unlock();
235 return -EINVAL;
236 }
237
David Ahern30bbaa12015-08-13 14:59:05 -0600238 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
Denis V. Luneva79878f2008-01-14 22:56:01 -0800239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 parms = in_dev->arp_parms;
241 __neigh_parms_put(neigh->parms);
242 neigh->parms = neigh_parms_clone(parms);
243 rcu_read_unlock();
244
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700245 if (!dev->header_ops) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 neigh->nud_state = NUD_NOARP;
247 neigh->ops = &arp_direct_ops;
David S. Miller8f40b162011-07-17 13:34:11 -0700248 neigh->output = neigh_direct_output;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 } else {
250 /* Good devices (checked by reading texts, but only Ethernet is
251 tested)
252
253 ARPHRD_ETHER: (ethernet, apfddi)
254 ARPHRD_FDDI: (fddi)
255 ARPHRD_IEEE802: (tr)
256 ARPHRD_METRICOM: (strip)
257 ARPHRD_ARCNET:
258 etc. etc. etc.
259
260 ARPHRD_IPDDP will also work, if author repairs it.
261 I did not it, because this driver does not work even
262 in old paradigm.
263 */
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 if (neigh->type == RTN_MULTICAST) {
266 neigh->nud_state = NUD_NOARP;
267 arp_mc_map(addr, neigh->ha, dev, 1);
Changli Gaodeffd772010-09-02 03:56:51 +0000268 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 neigh->nud_state = NUD_NOARP;
270 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
Changli Gaodeffd772010-09-02 03:56:51 +0000271 } else if (neigh->type == RTN_BROADCAST ||
272 (dev->flags & IFF_POINTOPOINT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 neigh->nud_state = NUD_NOARP;
274 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
275 }
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700276
277 if (dev->header_ops->cache)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 neigh->ops = &arp_hh_ops;
279 else
280 neigh->ops = &arp_generic_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700281
Changli Gaodeffd772010-09-02 03:56:51 +0000282 if (neigh->nud_state & NUD_VALID)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 neigh->output = neigh->ops->connected_output;
284 else
285 neigh->output = neigh->ops->output;
286 }
287 return 0;
288}
289
290static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
291{
292 dst_link_failure(skb);
293 kfree_skb(skb);
294}
295
Thomas Graf0accfc22015-07-21 10:43:57 +0200296/* Create and send an arp packet. */
297static void arp_send_dst(int type, int ptype, __be32 dest_ip,
298 struct net_device *dev, __be32 src_ip,
299 const unsigned char *dest_hw,
300 const unsigned char *src_hw,
Jiri Benc63d008a2015-09-22 18:12:11 +0200301 const unsigned char *target_hw,
302 struct dst_entry *dst)
Thomas Graf0accfc22015-07-21 10:43:57 +0200303{
304 struct sk_buff *skb;
305
306 /* arp on this interface. */
307 if (dev->flags & IFF_NOARP)
308 return;
309
310 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
311 dest_hw, src_hw, target_hw);
312 if (!skb)
313 return;
314
Jiri Benc181a4222015-10-01 16:25:43 +0200315 skb_dst_set(skb, dst_clone(dst));
Thomas Graf0accfc22015-07-21 10:43:57 +0200316 arp_xmit(skb);
317}
318
319void arp_send(int type, int ptype, __be32 dest_ip,
320 struct net_device *dev, __be32 src_ip,
321 const unsigned char *dest_hw, const unsigned char *src_hw,
322 const unsigned char *target_hw)
323{
324 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
325 target_hw, NULL);
326}
327EXPORT_SYMBOL(arp_send);
328
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
330{
Al Viroa61ced52006-09-26 21:27:54 -0700331 __be32 saddr = 0;
Cong Wangcf0be8802012-12-23 15:23:16 +0000332 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 struct net_device *dev = neigh->dev;
Changli Gaodeffd772010-09-02 03:56:51 +0000334 __be32 target = *(__be32 *)neigh->primary_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 int probes = atomic_read(&neigh->probes);
Eric Dumazet4b4194c2010-06-22 07:43:15 +0000336 struct in_device *in_dev;
Jiri Benc63d008a2015-09-22 18:12:11 +0200337 struct dst_entry *dst = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
Eric Dumazet4b4194c2010-06-22 07:43:15 +0000339 rcu_read_lock();
340 in_dev = __in_dev_get_rcu(dev);
341 if (!in_dev) {
342 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 return;
Eric Dumazet4b4194c2010-06-22 07:43:15 +0000344 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
346 default:
347 case 0: /* By default announce any local IP */
David Ahern30bbaa12015-08-13 14:59:05 -0600348 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
Changli Gaodeffd772010-09-02 03:56:51 +0000349 ip_hdr(skb)->saddr) == RTN_LOCAL)
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700350 saddr = ip_hdr(skb)->saddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 break;
352 case 1: /* Restrict announcements of saddr in same subnet */
353 if (!skb)
354 break;
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700355 saddr = ip_hdr(skb)->saddr;
David Ahern30bbaa12015-08-13 14:59:05 -0600356 if (inet_addr_type_dev_table(dev_net(dev), dev,
357 saddr) == RTN_LOCAL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 /* saddr should be known to target */
359 if (inet_addr_onlink(in_dev, target, saddr))
360 break;
361 }
362 saddr = 0;
363 break;
364 case 2: /* Avoid secondary IPs, get a primary/preferred one */
365 break;
366 }
Eric Dumazet4b4194c2010-06-22 07:43:15 +0000367 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (!saddr)
370 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
371
Jiri Pirko1f9248e2013-12-07 19:26:53 +0100372 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
Changli Gaodeffd772010-09-02 03:56:51 +0000373 if (probes < 0) {
374 if (!(neigh->nud_state & NUD_VALID))
Joe Perches91df42b2012-05-15 14:11:54 +0000375 pr_debug("trying to ucast probe in NUD_INVALID\n");
Eric Dumazet96503882012-12-21 07:32:10 +0000376 neigh_ha_snapshot(dst_ha, neigh, dev);
Cong Wangcf0be8802012-12-23 15:23:16 +0000377 dst_hw = dst_ha;
Changli Gaodeffd772010-09-02 03:56:51 +0000378 } else {
Jiri Pirko1f9248e2013-12-07 19:26:53 +0100379 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
Changli Gaodeffd772010-09-02 03:56:51 +0000380 if (probes < 0) {
Changli Gaodeffd772010-09-02 03:56:51 +0000381 neigh_app_ns(neigh);
Changli Gaodeffd772010-09-02 03:56:51 +0000382 return;
383 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 }
385
Jiri Benc63d008a2015-09-22 18:12:11 +0200386 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
Jiri Benc181a4222015-10-01 16:25:43 +0200387 dst = skb_dst(skb);
Thomas Graf0accfc22015-07-21 10:43:57 +0200388 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
Jiri Benc63d008a2015-09-22 18:12:11 +0200389 dst_hw, dev->dev_addr, NULL, dst);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390}
391
Denis V. Lunev9bd85e32008-01-14 23:05:55 -0800392static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393{
Nicolas Dichtelb601fa192013-12-10 15:02:40 +0100394 struct net *net = dev_net(in_dev->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 int scope;
396
397 switch (IN_DEV_ARP_IGNORE(in_dev)) {
398 case 0: /* Reply, the tip is already validated */
399 return 0;
400 case 1: /* Reply only if tip is configured on the incoming interface */
401 sip = 0;
402 scope = RT_SCOPE_HOST;
403 break;
404 case 2: /*
405 * Reply only if tip is configured on the incoming interface
406 * and is in same subnet as sip
407 */
408 scope = RT_SCOPE_HOST;
409 break;
410 case 3: /* Do not reply for scope host addresses */
411 sip = 0;
412 scope = RT_SCOPE_LINK;
Nicolas Dichtelb601fa192013-12-10 15:02:40 +0100413 in_dev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 break;
415 case 4: /* Reserved */
416 case 5:
417 case 6:
418 case 7:
419 return 0;
420 case 8: /* Do not reply */
421 return 1;
422 default:
423 return 0;
424 }
Nicolas Dichtelb601fa192013-12-10 15:02:40 +0100425 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426}
427
Al Viroed9bad02006-09-27 18:36:36 -0700428static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 struct rtable *rt;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900431 int flag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 /*unsigned long now; */
Pavel Emelyanovca12a1a2008-07-16 20:28:42 -0700433 struct net *net = dev_net(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434
David S. Miller78fbfd82011-03-12 00:00:52 -0500435 rt = ip_route_output(net, sip, tip, 0, 0);
David S. Millerb23dd4f2011-03-02 14:31:35 -0800436 if (IS_ERR(rt))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 return 1;
Changli Gaod8d1f302010-06-10 23:31:35 -0700438 if (rt->dst.dev != dev) {
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700439 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 flag = 1;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900441 }
442 ip_rt_put(rt);
443 return flag;
444}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446/*
447 * Check if we can use proxy ARP for this path
448 */
Jesper Dangaard Brouer65324142010-01-05 05:50:47 +0000449static inline int arp_fwd_proxy(struct in_device *in_dev,
450 struct net_device *dev, struct rtable *rt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451{
452 struct in_device *out_dev;
453 int imi, omi = -1;
454
Changli Gaod8d1f302010-06-10 23:31:35 -0700455 if (rt->dst.dev == dev)
Jesper Dangaard Brouer65324142010-01-05 05:50:47 +0000456 return 0;
457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 if (!IN_DEV_PROXY_ARP(in_dev))
459 return 0;
Changli Gaodeffd772010-09-02 03:56:51 +0000460 imi = IN_DEV_MEDIUM_ID(in_dev);
461 if (imi == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 return 1;
463 if (imi == -1)
464 return 0;
465
466 /* place to check for proxy_arp for routes */
467
Changli Gaod8d1f302010-06-10 23:31:35 -0700468 out_dev = __in_dev_get_rcu(rt->dst.dev);
Eric Dumazetfaa9dcf2010-06-03 04:09:10 +0000469 if (out_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 omi = IN_DEV_MEDIUM_ID(out_dev);
Eric Dumazetfaa9dcf2010-06-03 04:09:10 +0000471
Eric Dumazeta02cec22010-09-22 20:43:57 +0000472 return omi != imi && omi != -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473}
474
475/*
Jesper Dangaard Brouer65324142010-01-05 05:50:47 +0000476 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
477 *
478 * RFC3069 supports proxy arp replies back to the same interface. This
479 * is done to support (ethernet) switch features, like RFC 3069, where
480 * the individual ports are not allowed to communicate with each
481 * other, BUT they are allowed to talk to the upstream router. As
482 * described in RFC 3069, it is possible to allow these hosts to
483 * communicate through the upstream router, by proxy_arp'ing.
484 *
485 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
486 *
487 * This technology is known by different names:
488 * In RFC 3069 it is called VLAN Aggregation.
489 * Cisco and Allied Telesyn call it Private VLAN.
490 * Hewlett-Packard call it Source-Port filtering or port-isolation.
491 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
492 *
493 */
494static inline int arp_fwd_pvlan(struct in_device *in_dev,
495 struct net_device *dev, struct rtable *rt,
496 __be32 sip, __be32 tip)
497{
498 /* Private VLAN is only concerned about the same ethernet segment */
Changli Gaod8d1f302010-06-10 23:31:35 -0700499 if (rt->dst.dev != dev)
Jesper Dangaard Brouer65324142010-01-05 05:50:47 +0000500 return 0;
501
502 /* Don't reply on self probes (often done by windowz boxes)*/
503 if (sip == tip)
504 return 0;
505
506 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
507 return 1;
508 else
509 return 0;
510}
511
512/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 * Interface to link layer: send routine and receive handler.
514 */
515
516/*
Ian Morris51456b22015-04-03 09:17:26 +0100517 * Create an arp packet. If dest_hw is not set, we create a broadcast
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 * message.
519 */
Al Viroed9bad02006-09-27 18:36:36 -0700520struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
521 struct net_device *dev, __be32 src_ip,
Jan Engelhardtabfdf1c2008-01-31 03:59:24 -0800522 const unsigned char *dest_hw,
523 const unsigned char *src_hw,
524 const unsigned char *target_hw)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525{
526 struct sk_buff *skb;
527 struct arphdr *arp;
528 unsigned char *arp_ptr;
Herbert Xu66088242011-11-18 02:20:04 +0000529 int hlen = LL_RESERVED_SPACE(dev);
530 int tlen = dev->needed_tailroom;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
532 /*
533 * Allocate a buffer
534 */
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900535
Herbert Xu66088242011-11-18 02:20:04 +0000536 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
Ian Morris51456b22015-04-03 09:17:26 +0100537 if (!skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 return NULL;
539
Herbert Xu66088242011-11-18 02:20:04 +0000540 skb_reserve(skb, hlen);
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -0700541 skb_reset_network_header(skb);
Pavel Emelyanov988b7052008-03-03 12:20:57 -0800542 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 skb->dev = dev;
544 skb->protocol = htons(ETH_P_ARP);
Ian Morris51456b22015-04-03 09:17:26 +0100545 if (!src_hw)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 src_hw = dev->dev_addr;
Ian Morris51456b22015-04-03 09:17:26 +0100547 if (!dest_hw)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 dest_hw = dev->broadcast;
549
550 /*
551 * Fill the device header for the ARP frame
552 */
Stephen Hemminger0c4e8582007-10-09 01:36:32 -0700553 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 goto out;
555
556 /*
557 * Fill out the arp protocol part.
558 *
559 * The arp hardware type should match the device type, except for FDDI,
560 * which (according to RFC 1390) should always equal 1 (Ethernet).
561 */
562 /*
563 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
564 * DIX code for the protocol. Make these device structure fields.
565 */
566 switch (dev->type) {
567 default:
568 arp->ar_hrd = htons(dev->type);
569 arp->ar_pro = htons(ETH_P_IP);
570 break;
571
Igor Maravic40e47832011-12-05 02:25:57 +0000572#if IS_ENABLED(CONFIG_AX25)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 case ARPHRD_AX25:
574 arp->ar_hrd = htons(ARPHRD_AX25);
575 arp->ar_pro = htons(AX25_P_IP);
576 break;
577
Igor Maravic40e47832011-12-05 02:25:57 +0000578#if IS_ENABLED(CONFIG_NETROM)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 case ARPHRD_NETROM:
580 arp->ar_hrd = htons(ARPHRD_NETROM);
581 arp->ar_pro = htons(AX25_P_IP);
582 break;
583#endif
584#endif
585
Igor Maravic40e47832011-12-05 02:25:57 +0000586#if IS_ENABLED(CONFIG_FDDI)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 case ARPHRD_FDDI:
588 arp->ar_hrd = htons(ARPHRD_ETHER);
589 arp->ar_pro = htons(ETH_P_IP);
590 break;
591#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 }
593
594 arp->ar_hln = dev->addr_len;
595 arp->ar_pln = 4;
596 arp->ar_op = htons(type);
597
Changli Gaodeffd772010-09-02 03:56:51 +0000598 arp_ptr = (unsigned char *)(arp + 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
600 memcpy(arp_ptr, src_hw, dev->addr_len);
Jianjun Kongf4cca7f2008-11-03 02:48:14 -0800601 arp_ptr += dev->addr_len;
602 memcpy(arp_ptr, &src_ip, 4);
603 arp_ptr += 4;
YOSHIFUJI Hideaki / 吉藤英明6752c8d2013-03-25 08:26:16 +0000604
605 switch (dev->type) {
606#if IS_ENABLED(CONFIG_FIREWIRE_NET)
607 case ARPHRD_IEEE1394:
608 break;
609#endif
610 default:
Ian Morris00db4122015-04-03 09:17:27 +0100611 if (target_hw)
YOSHIFUJI Hideaki / 吉藤英明6752c8d2013-03-25 08:26:16 +0000612 memcpy(arp_ptr, target_hw, dev->addr_len);
613 else
614 memset(arp_ptr, 0, dev->addr_len);
615 arp_ptr += dev->addr_len;
616 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 memcpy(arp_ptr, &dest_ip, 4);
618
619 return skb;
620
621out:
622 kfree_skb(skb);
623 return NULL;
624}
Eric Dumazet4bc2f182010-07-09 21:22:10 +0000625EXPORT_SYMBOL(arp_create);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626
Eric W. Biederman0c4b51f2015-09-15 20:04:18 -0500627static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
Eric W. Biedermanf9e43062015-09-15 20:04:05 -0500628{
629 return dev_queue_xmit(skb);
630}
631
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632/*
633 * Send an arp packet.
634 */
635void arp_xmit(struct sk_buff *skb)
636{
637 /* Send it off, maybe filter it using firewalling first. */
Eric W. Biederman29a26a52015-09-15 20:04:16 -0500638 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
639 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
640 arp_xmit_finish);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641}
Eric Dumazet4bc2f182010-07-09 21:22:10 +0000642EXPORT_SYMBOL(arp_xmit);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
644/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 * Process an arp request.
646 */
647
Eric W. Biederman0c4b51f2015-09-15 20:04:18 -0500648static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649{
650 struct net_device *dev = skb->dev;
Eric Dumazetfaa9dcf2010-06-03 04:09:10 +0000651 struct in_device *in_dev = __in_dev_get_rcu(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 struct arphdr *arp;
653 unsigned char *arp_ptr;
654 struct rtable *rt;
Mark Rydene0260fe2007-12-19 23:38:11 -0800655 unsigned char *sha;
Al Viro9e12bb22006-09-26 21:25:20 -0700656 __be32 sip, tip;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 u16 dev_type = dev->type;
658 int addr_type;
659 struct neighbour *n;
Jiri Benc63d008a2015-09-22 18:12:11 +0200660 struct dst_entry *reply_dst = NULL;
Salam Noureddine56022a82013-12-24 14:17:02 -0800661 bool is_garp = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662
663 /* arp_rcv below verifies the ARP header and verifies the device
664 * is ARP'able.
665 */
666
Ian Morris51456b22015-04-03 09:17:26 +0100667 if (!in_dev)
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000668 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669
Arnaldo Carvalho de Melod0a92be2007-03-12 20:56:31 -0300670 arp = arp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
672 switch (dev_type) {
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900673 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 if (arp->ar_pro != htons(ETH_P_IP) ||
675 htons(dev_type) != arp->ar_hrd)
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000676 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 case ARPHRD_ETHER:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 case ARPHRD_FDDI:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 case ARPHRD_IEEE802:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 /*
Paul Gortmaker211ed862012-05-10 17:14:35 -0400682 * ETHERNET, and Fibre Channel (which are IEEE 802
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 * devices, according to RFC 2625) devices will accept ARP
684 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
685 * This is the case also of FDDI, where the RFC 1390 says that
686 * FDDI devices should accept ARP hardware of (1) Ethernet,
687 * however, to be more robust, we'll accept both 1 (Ethernet)
688 * or 6 (IEEE 802.2)
689 */
690 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
691 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
692 arp->ar_pro != htons(ETH_P_IP))
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000693 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 case ARPHRD_AX25:
696 if (arp->ar_pro != htons(AX25_P_IP) ||
697 arp->ar_hrd != htons(ARPHRD_AX25))
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000698 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 case ARPHRD_NETROM:
701 if (arp->ar_pro != htons(AX25_P_IP) ||
702 arp->ar_hrd != htons(ARPHRD_NETROM))
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000703 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 }
706
707 /* Understand only these message types */
708
709 if (arp->ar_op != htons(ARPOP_REPLY) &&
710 arp->ar_op != htons(ARPOP_REQUEST))
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000711 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
713/*
714 * Extract fields
715 */
Changli Gaodeffd772010-09-02 03:56:51 +0000716 arp_ptr = (unsigned char *)(arp + 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 sha = arp_ptr;
718 arp_ptr += dev->addr_len;
719 memcpy(&sip, arp_ptr, 4);
720 arp_ptr += 4;
YOSHIFUJI Hideaki / 吉藤英明6752c8d2013-03-25 08:26:16 +0000721 switch (dev_type) {
722#if IS_ENABLED(CONFIG_FIREWIRE_NET)
723 case ARPHRD_IEEE1394:
724 break;
725#endif
726 default:
727 arp_ptr += dev->addr_len;
728 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 memcpy(&tip, arp_ptr, 4);
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900730/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 * Check for bad requests for 127.x.x.x and requests for multicast
732 * addresses. If this is one such, delete it.
733 */
Thomas Grafd0daebc32012-06-12 00:44:01 +0000734 if (ipv4_is_multicast(tip) ||
735 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000736 goto out_free_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737
Johannes Berg97daf332016-02-04 13:31:18 +0100738 /*
739 * For some 802.11 wireless deployments (and possibly other networks),
740 * there will be an ARP proxy and gratuitous ARP frames are attacks
741 * and thus should not be accepted.
742 */
743 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000744 goto out_free_skb;
Johannes Berg97daf332016-02-04 13:31:18 +0100745
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746/*
747 * Special case: We must set Frame Relay source Q.922 address
748 */
749 if (dev_type == ARPHRD_DLCI)
750 sha = dev->broadcast;
751
752/*
753 * Process entry. The idea here is we want to send a reply if it is a
754 * request for us or if it is a request for someone else that we hold
755 * a proxy for. We want to add an entry to our cache if it is a reply
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900756 * to us or if it is a request for our address.
757 * (The assumption for this last is that if someone is requesting our
758 * address, they are probably intending to talk to us, so it saves time
759 * if we cache their address. Their address is also probably not in
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 * our cache, since ours is not in their cache.)
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900761 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 * Putting this another way, we only care about replies if they are to
763 * us, in which case we add them to the cache. For requests, we care
764 * about those for us and those for our proxies. We reply to both,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900765 * and in the case of requests for us we add the requester to the arp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 * cache.
767 */
768
Jiri Benc63d008a2015-09-22 18:12:11 +0200769 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
770 reply_dst = (struct dst_entry *)
771 iptunnel_metadata_reply(skb_metadata_dst(skb),
772 GFP_ATOMIC);
773
Eric W. Biedermanf8a68e72009-06-30 16:27:17 +0000774 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
775 if (sip == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 if (arp->ar_op == htons(ARPOP_REQUEST) &&
David Ahern30bbaa12015-08-13 14:59:05 -0600777 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
Denis V. Lunev9bd85e32008-01-14 23:05:55 -0800778 !arp_ignore(in_dev, sip, tip))
Jiri Benc63d008a2015-09-22 18:12:11 +0200779 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
780 sha, dev->dev_addr, sha, reply_dst);
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000781 goto out_consume_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 }
783
784 if (arp->ar_op == htons(ARPOP_REQUEST) &&
David S. Millerc6cffba2012-07-26 11:14:38 +0000785 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786
Eric Dumazet511c3f92009-06-02 05:14:27 +0000787 rt = skb_rtable(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 addr_type = rt->rt_type;
789
790 if (addr_type == RTN_LOCAL) {
Changli Gaodeffd772010-09-02 03:56:51 +0000791 int dont_send;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
Changli Gaodeffd772010-09-02 03:56:51 +0000793 dont_send = arp_ignore(in_dev, sip, tip);
Ben Greear8164f1b2008-11-16 19:19:38 -0800794 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
Changli Gaoae9c4162010-12-01 20:07:31 +0000795 dont_send = arp_filter(sip, tip, dev);
Ben Greear8164f1b2008-11-16 19:19:38 -0800796 if (!dont_send) {
797 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
798 if (n) {
Jiri Benc63d008a2015-09-22 18:12:11 +0200799 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
800 sip, dev, tip, sha,
801 dev->dev_addr, sha,
802 reply_dst);
Ben Greear8164f1b2008-11-16 19:19:38 -0800803 neigh_release(n);
804 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 }
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000806 goto out_consume_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 } else if (IN_DEV_FORWARD(in_dev)) {
Jesper Dangaard Brouer65324142010-01-05 05:50:47 +0000808 if (addr_type == RTN_UNICAST &&
809 (arp_fwd_proxy(in_dev, dev, rt) ||
810 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
Thomas Graf70620c42012-02-10 04:07:11 +0000811 (rt->dst.dev != dev &&
812 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
814 if (n)
815 neigh_release(n);
816
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900817 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 skb->pkt_type == PACKET_HOST ||
Jiri Pirko1f9248e2013-12-07 19:26:53 +0100819 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
Jiri Benc63d008a2015-09-22 18:12:11 +0200820 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
821 sip, dev, tip, sha,
822 dev->dev_addr, sha,
823 reply_dst);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 } else {
Changli Gaodeffd772010-09-02 03:56:51 +0000825 pneigh_enqueue(&arp_tbl,
826 in_dev->arp_parms, skb);
Jiri Benc181a4222015-10-01 16:25:43 +0200827 goto out_free_dst;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 }
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000829 goto out_consume_skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 }
831 }
832 }
833
834 /* Update our ARP tables */
835
836 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
837
Neil Horman124d37e2012-03-15 05:25:58 +0000838 if (IN_DEV_ARP_ACCEPT(in_dev)) {
David Ahern30bbaa12015-08-13 14:59:05 -0600839 unsigned int addr_type = inet_addr_type_dev_table(net, dev, sip);
840
Neil Hormanabd596a2006-03-20 22:39:47 -0800841 /* Unsolicited ARP is not accepted by default.
842 It is possible, that this option should be enabled for some
843 devices (strip is candidate)
844 */
Salam Noureddine56022a82013-12-24 14:17:02 -0800845 is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
David Ahern30bbaa12015-08-13 14:59:05 -0600846 addr_type == RTN_UNICAST;
Salam Noureddine56022a82013-12-24 14:17:02 -0800847
Ian Morris51456b22015-04-03 09:17:26 +0100848 if (!n &&
Salam Noureddine56022a82013-12-24 14:17:02 -0800849 ((arp->ar_op == htons(ARPOP_REPLY) &&
David Ahern30bbaa12015-08-13 14:59:05 -0600850 addr_type == RTN_UNICAST) || is_garp))
Jean Delvare1b1ac752007-07-14 20:51:44 -0700851 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
Neil Hormanabd596a2006-03-20 22:39:47 -0800852 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853
854 if (n) {
855 int state = NUD_REACHABLE;
856 int override;
857
858 /* If several different ARP replies follows back-to-back,
859 use the FIRST one. It is possible, if several proxy
860 agents are active. Taking the first reply prevents
861 arp trashing and chooses the fastest router.
862 */
Salam Noureddine56022a82013-12-24 14:17:02 -0800863 override = time_after(jiffies,
864 n->updated +
865 NEIGH_VAR(n->parms, LOCKTIME)) ||
866 is_garp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867
868 /* Broadcast replies and request packets
869 do not assert neighbour reachability.
870 */
871 if (arp->ar_op != htons(ARPOP_REPLY) ||
872 skb->pkt_type != PACKET_HOST)
873 state = NUD_STALE;
Changli Gaodeffd772010-09-02 03:56:51 +0000874 neigh_update(n, sha, state,
875 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 neigh_release(n);
877 }
878
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000879out_consume_skb:
Neil Hormanead2ceb2009-03-11 09:49:55 +0000880 consume_skb(skb);
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000881
Jiri Benc181a4222015-10-01 16:25:43 +0200882out_free_dst:
883 dst_release(reply_dst);
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000884 return NET_RX_SUCCESS;
885
886out_free_skb:
887 kfree_skb(skb);
888 return NET_RX_DROP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889}
890
Herbert Xu444fc8f2005-10-03 14:18:10 -0700891static void parp_redo(struct sk_buff *skb)
892{
Eric W. Biederman0c4b51f2015-09-15 20:04:18 -0500893 arp_process(dev_net(skb->dev), NULL, skb);
Herbert Xu444fc8f2005-10-03 14:18:10 -0700894}
895
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896
897/*
898 * Receive an arp request from the device layer.
899 */
900
Adrian Bunk6c97e722006-04-12 13:57:59 -0700901static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
902 struct packet_type *pt, struct net_device *orig_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903{
Eric Dumazet044453b2013-02-08 18:48:21 +0000904 const struct arphdr *arp;
905
Rick Jones825bae52014-09-25 10:55:28 -0700906 /* do not tweak dropwatch on an ARP we will ignore */
Eric Dumazet044453b2013-02-08 18:48:21 +0000907 if (dev->flags & IFF_NOARP ||
908 skb->pkt_type == PACKET_OTHERHOST ||
909 skb->pkt_type == PACKET_LOOPBACK)
Rick Jones825bae52014-09-25 10:55:28 -0700910 goto consumeskb;
Eric Dumazet044453b2013-02-08 18:48:21 +0000911
912 skb = skb_share_check(skb, GFP_ATOMIC);
913 if (!skb)
914 goto out_of_mem;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915
916 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
Pavel Emelyanov988b7052008-03-03 12:20:57 -0800917 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 goto freeskb;
919
Arnaldo Carvalho de Melod0a92be2007-03-12 20:56:31 -0300920 arp = arp_hdr(skb);
Eric Dumazet044453b2013-02-08 18:48:21 +0000921 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 goto freeskb;
923
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700924 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
925
Eric W. Biederman29a26a52015-09-15 20:04:16 -0500926 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
927 dev_net(dev), NULL, skb, dev, NULL,
928 arp_process);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929
Rick Jones825bae52014-09-25 10:55:28 -0700930consumeskb:
931 consume_skb(skb);
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000932 return NET_RX_SUCCESS;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933freeskb:
934 kfree_skb(skb);
935out_of_mem:
Zhang Shengju8dfd3292016-03-04 14:07:54 +0000936 return NET_RX_DROP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937}
938
939/*
940 * User level interface (ioctl)
941 */
942
943/*
944 * Set (create) an ARP cache entry.
945 */
946
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800947static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800948{
Ian Morris51456b22015-04-03 09:17:26 +0100949 if (!dev) {
Pavel Emelyanov586f1212007-12-16 13:32:48 -0800950 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800951 return 0;
952 }
Eric Dumazetc5066532011-01-24 13:16:16 -0800953 if (__in_dev_get_rtnl(dev)) {
954 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800955 return 0;
956 }
957 return -ENXIO;
958}
959
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800960static int arp_req_set_public(struct net *net, struct arpreq *r,
961 struct net_device *dev)
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800962{
963 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
964 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
965
966 if (mask && mask != htonl(0xFFFFFFFF))
967 return -EINVAL;
968 if (!dev && (r->arp_flags & ATF_COM)) {
Eric Dumazet941666c2010-12-05 01:23:53 +0000969 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
Changli Gaodeffd772010-09-02 03:56:51 +0000970 r->arp_ha.sa_data);
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800971 if (!dev)
972 return -ENODEV;
973 }
974 if (mask) {
Ian Morris51456b22015-04-03 09:17:26 +0100975 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800976 return -ENOBUFS;
977 return 0;
978 }
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800979
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800980 return arp_req_set_proxy(net, dev, 1);
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800981}
982
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800983static int arp_req_set(struct net *net, struct arpreq *r,
Changli Gaodeffd772010-09-02 03:56:51 +0000984 struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985{
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800986 __be32 ip;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 struct neighbour *neigh;
988 int err;
989
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800990 if (r->arp_flags & ATF_PUBL)
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800991 return arp_req_set_public(net, r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800993 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 if (r->arp_flags & ATF_PERM)
995 r->arp_flags |= ATF_COM;
Ian Morris51456b22015-04-03 09:17:26 +0100996 if (!dev) {
David S. Miller78fbfd82011-03-12 00:00:52 -0500997 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
David S. Millerb23dd4f2011-03-02 14:31:35 -0800998
999 if (IS_ERR(rt))
1000 return PTR_ERR(rt);
Changli Gaod8d1f302010-06-10 23:31:35 -07001001 dev = rt->dst.dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 ip_rt_put(rt);
1003 if (!dev)
1004 return -EINVAL;
1005 }
1006 switch (dev->type) {
Igor Maravic40e47832011-12-05 02:25:57 +00001007#if IS_ENABLED(CONFIG_FDDI)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 case ARPHRD_FDDI:
1009 /*
1010 * According to RFC 1390, FDDI devices should accept ARP
1011 * hardware types of 1 (Ethernet). However, to be more
1012 * robust, we'll accept hardware types of either 1 (Ethernet)
1013 * or 6 (IEEE 802.2).
1014 */
1015 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1016 r->arp_ha.sa_family != ARPHRD_ETHER &&
1017 r->arp_ha.sa_family != ARPHRD_IEEE802)
1018 return -EINVAL;
1019 break;
1020#endif
1021 default:
1022 if (r->arp_ha.sa_family != dev->type)
1023 return -EINVAL;
1024 break;
1025 }
1026
1027 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1028 err = PTR_ERR(neigh);
1029 if (!IS_ERR(neigh)) {
Eric Dumazet95c96172012-04-15 05:58:06 +00001030 unsigned int state = NUD_STALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 if (r->arp_flags & ATF_PERM)
1032 state = NUD_PERMANENT;
Changli Gaodeffd772010-09-02 03:56:51 +00001033 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001034 r->arp_ha.sa_data : NULL, state,
Changli Gaodeffd772010-09-02 03:56:51 +00001035 NEIGH_UPDATE_F_OVERRIDE |
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 NEIGH_UPDATE_F_ADMIN);
1037 neigh_release(neigh);
1038 }
1039 return err;
1040}
1041
Eric Dumazet95c96172012-04-15 05:58:06 +00001042static unsigned int arp_state_to_flags(struct neighbour *neigh)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 if (neigh->nud_state&NUD_PERMANENT)
Changli Gaodeffd772010-09-02 03:56:51 +00001045 return ATF_PERM | ATF_COM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 else if (neigh->nud_state&NUD_VALID)
Changli Gaodeffd772010-09-02 03:56:51 +00001047 return ATF_COM;
1048 else
1049 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050}
1051
1052/*
1053 * Get an ARP cache entry.
1054 */
1055
1056static int arp_req_get(struct arpreq *r, struct net_device *dev)
1057{
Al Viroed9bad02006-09-27 18:36:36 -07001058 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059 struct neighbour *neigh;
1060 int err = -ENXIO;
1061
1062 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1063 if (neigh) {
Eric Dumazet11c91ef2015-07-27 11:33:50 +02001064 if (!(neigh->nud_state & NUD_NOARP)) {
1065 read_lock_bh(&neigh->lock);
1066 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1067 r->arp_flags = arp_state_to_flags(neigh);
1068 read_unlock_bh(&neigh->lock);
1069 r->arp_ha.sa_family = dev->type;
1070 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1071 err = 0;
1072 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 neigh_release(neigh);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 }
1075 return err;
1076}
1077
Stephen Hemminger7195cf72013-12-28 11:07:18 -08001078static int arp_invalidate(struct net_device *dev, __be32 ip)
Maxim Levitsky545ecdc2011-01-08 13:57:12 +00001079{
1080 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1081 int err = -ENXIO;
1082
1083 if (neigh) {
1084 if (neigh->nud_state & ~NUD_NOARP)
1085 err = neigh_update(neigh, NULL, NUD_FAILED,
1086 NEIGH_UPDATE_F_OVERRIDE|
1087 NEIGH_UPDATE_F_ADMIN);
1088 neigh_release(neigh);
1089 }
1090
1091 return err;
1092}
Maxim Levitsky545ecdc2011-01-08 13:57:12 +00001093
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001094static int arp_req_delete_public(struct net *net, struct arpreq *r,
1095 struct net_device *dev)
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001096{
1097 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1098 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1099
1100 if (mask == htonl(0xFFFFFFFF))
Denis V. Lunev2db82b52008-01-14 22:58:55 -08001101 return pneigh_delete(&arp_tbl, net, &ip, dev);
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001102
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -08001103 if (mask)
1104 return -EINVAL;
1105
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001106 return arp_req_set_proxy(net, dev, 0);
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001107}
1108
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001109static int arp_req_delete(struct net *net, struct arpreq *r,
Changli Gaodeffd772010-09-02 03:56:51 +00001110 struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111{
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001112 __be32 ip;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001114 if (r->arp_flags & ATF_PUBL)
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001115 return arp_req_delete_public(net, r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001117 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
Ian Morris51456b22015-04-03 09:17:26 +01001118 if (!dev) {
David S. Miller78fbfd82011-03-12 00:00:52 -05001119 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
David S. Millerb23dd4f2011-03-02 14:31:35 -08001120 if (IS_ERR(rt))
1121 return PTR_ERR(rt);
Changli Gaod8d1f302010-06-10 23:31:35 -07001122 dev = rt->dst.dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 ip_rt_put(rt);
1124 if (!dev)
1125 return -EINVAL;
1126 }
Maxim Levitsky545ecdc2011-01-08 13:57:12 +00001127 return arp_invalidate(dev, ip);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128}
1129
1130/*
1131 * Handle an ARP layer I/O control request.
1132 */
1133
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001134int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135{
1136 int err;
1137 struct arpreq r;
1138 struct net_device *dev = NULL;
1139
1140 switch (cmd) {
Changli Gaodeffd772010-09-02 03:56:51 +00001141 case SIOCDARP:
1142 case SIOCSARP:
Eric W. Biederman52e804c2012-11-16 03:03:05 +00001143 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
Changli Gaodeffd772010-09-02 03:56:51 +00001144 return -EPERM;
1145 case SIOCGARP:
1146 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1147 if (err)
1148 return -EFAULT;
1149 break;
1150 default:
1151 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 }
1153
1154 if (r.arp_pa.sa_family != AF_INET)
1155 return -EPFNOSUPPORT;
1156
1157 if (!(r.arp_flags & ATF_PUBL) &&
Changli Gaodeffd772010-09-02 03:56:51 +00001158 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 return -EINVAL;
1160 if (!(r.arp_flags & ATF_NETMASK))
1161 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1162 htonl(0xFFFFFFFFUL);
Eric Dumazetc5066532011-01-24 13:16:16 -08001163 rtnl_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 if (r.arp_dev[0]) {
1165 err = -ENODEV;
Eric Dumazetc5066532011-01-24 13:16:16 -08001166 dev = __dev_get_by_name(net, r.arp_dev);
Ian Morris51456b22015-04-03 09:17:26 +01001167 if (!dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168 goto out;
1169
1170 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1171 if (!r.arp_ha.sa_family)
1172 r.arp_ha.sa_family = dev->type;
1173 err = -EINVAL;
1174 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1175 goto out;
1176 } else if (cmd == SIOCGARP) {
1177 err = -ENODEV;
1178 goto out;
1179 }
1180
Stephen Hemminger132adf52007-03-08 20:44:43 -08001181 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 case SIOCDARP:
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001183 err = arp_req_delete(net, &r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 break;
1185 case SIOCSARP:
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001186 err = arp_req_set(net, &r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 break;
1188 case SIOCGARP:
1189 err = arp_req_get(&r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 break;
1191 }
1192out:
Eric Dumazetc5066532011-01-24 13:16:16 -08001193 rtnl_unlock();
Eric Dumazet941666c2010-12-05 01:23:53 +00001194 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1195 err = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 return err;
1197}
1198
Changli Gaodeffd772010-09-02 03:56:51 +00001199static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1200 void *ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201{
Jiri Pirko351638e2013-05-28 01:30:21 +00001202 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
Timo Teräs6c8b4e32013-05-28 01:30:23 +00001203 struct netdev_notifier_change_info *change_info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204
1205 switch (event) {
1206 case NETDEV_CHANGEADDR:
1207 neigh_changeaddr(&arp_tbl, dev);
Nicolas Dichtelbafa6d92012-09-07 00:45:29 +00001208 rt_cache_flush(dev_net(dev));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 break;
Timo Teräs6c8b4e32013-05-28 01:30:23 +00001210 case NETDEV_CHANGE:
1211 change_info = ptr;
1212 if (change_info->flags_changed & IFF_NOARP)
1213 neigh_changeaddr(&arp_tbl, dev);
1214 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 default:
1216 break;
1217 }
1218
1219 return NOTIFY_DONE;
1220}
1221
1222static struct notifier_block arp_netdev_notifier = {
1223 .notifier_call = arp_netdev_event,
1224};
1225
1226/* Note, that it is not on notifier chain.
1227 It is necessary, that this routine was called after route cache will be
1228 flushed.
1229 */
1230void arp_ifdown(struct net_device *dev)
1231{
1232 neigh_ifdown(&arp_tbl, dev);
1233}
1234
1235
1236/*
1237 * Called once on startup.
1238 */
1239
Stephen Hemminger7546dd92009-03-09 08:18:29 +00001240static struct packet_type arp_packet_type __read_mostly = {
Harvey Harrison09640e62009-02-01 00:45:17 -08001241 .type = cpu_to_be16(ETH_P_ARP),
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 .func = arp_rcv,
1243};
1244
1245static int arp_proc_init(void);
1246
1247void __init arp_init(void)
1248{
WANG Congd7480fd2014-11-10 15:59:36 -08001249 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250
1251 dev_add_pack(&arp_packet_type);
1252 arp_proc_init();
1253#ifdef CONFIG_SYSCTL
Jiri Pirko73af6142013-12-07 19:26:55 +01001254 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255#endif
1256 register_netdevice_notifier(&arp_netdev_notifier);
1257}
1258
1259#ifdef CONFIG_PROC_FS
Igor Maravic40e47832011-12-05 02:25:57 +00001260#if IS_ENABLED(CONFIG_AX25)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
1262/* ------------------------------------------------------------------------ */
1263/*
1264 * ax25 -> ASCII conversion
1265 */
1266static char *ax2asc2(ax25_address *a, char *buf)
1267{
1268 char c, *s;
1269 int n;
1270
1271 for (n = 0, s = buf; n < 6; n++) {
1272 c = (a->ax25_call[n] >> 1) & 0x7F;
1273
Changli Gaodeffd772010-09-02 03:56:51 +00001274 if (c != ' ')
1275 *s++ = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 }
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001277
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 *s++ = '-';
Changli Gaodeffd772010-09-02 03:56:51 +00001279 n = (a->ax25_call[6] >> 1) & 0x0F;
1280 if (n > 9) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 *s++ = '1';
1282 n -= 10;
1283 }
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001284
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 *s++ = n + '0';
1286 *s++ = '\0';
1287
1288 if (*buf == '\0' || *buf == '-')
Changli Gaodeffd772010-09-02 03:56:51 +00001289 return "*";
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290
1291 return buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292}
1293#endif /* CONFIG_AX25 */
1294
1295#define HBUFFERLEN 30
1296
1297static void arp_format_neigh_entry(struct seq_file *seq,
1298 struct neighbour *n)
1299{
1300 char hbuffer[HBUFFERLEN];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301 int k, j;
1302 char tbuf[16];
1303 struct net_device *dev = n->dev;
1304 int hatype = dev->type;
1305
1306 read_lock(&n->lock);
1307 /* Convert hardware address to XX:XX:XX:XX ... form. */
Igor Maravic40e47832011-12-05 02:25:57 +00001308#if IS_ENABLED(CONFIG_AX25)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1310 ax2asc2((ax25_address *)n->ha, hbuffer);
1311 else {
1312#endif
1313 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
Denis Cheng51f82a22008-05-21 17:34:32 -07001314 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1315 hbuffer[k++] = hex_asc_lo(n->ha[j]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316 hbuffer[k++] = ':';
1317 }
roel kluina3e8ee62009-07-29 23:46:59 +00001318 if (k != 0)
1319 --k;
1320 hbuffer[k] = 0;
Igor Maravic40e47832011-12-05 02:25:57 +00001321#if IS_ENABLED(CONFIG_AX25)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 }
1323#endif
Harvey Harrison673d57e2008-10-31 00:53:57 -07001324 sprintf(tbuf, "%pI4", n->primary_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1326 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1327 read_unlock(&n->lock);
1328}
1329
1330static void arp_format_pneigh_entry(struct seq_file *seq,
1331 struct pneigh_entry *n)
1332{
1333 struct net_device *dev = n->dev;
1334 int hatype = dev ? dev->type : 0;
1335 char tbuf[16];
1336
Harvey Harrison673d57e2008-10-31 00:53:57 -07001337 sprintf(tbuf, "%pI4", n->key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1339 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1340 dev ? dev->name : "*");
1341}
1342
1343static int arp_seq_show(struct seq_file *seq, void *v)
1344{
1345 if (v == SEQ_START_TOKEN) {
1346 seq_puts(seq, "IP address HW type Flags "
1347 "HW address Mask Device\n");
1348 } else {
1349 struct neigh_seq_state *state = seq->private;
1350
1351 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1352 arp_format_pneigh_entry(seq, v);
1353 else
1354 arp_format_neigh_entry(seq, v);
1355 }
1356
1357 return 0;
1358}
1359
1360static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1361{
1362 /* Don't want to confuse "arp -a" w/ magic entries,
1363 * so we tell the generic iterator to skip NUD_NOARP.
1364 */
1365 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1366}
1367
1368/* ------------------------------------------------------------------------ */
1369
Stephen Hemmingerf6908082007-03-12 14:34:29 -07001370static const struct seq_operations arp_seq_ops = {
Changli Gaodeffd772010-09-02 03:56:51 +00001371 .start = arp_seq_start,
1372 .next = neigh_seq_next,
1373 .stop = neigh_seq_stop,
1374 .show = arp_seq_show,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375};
1376
1377static int arp_seq_open(struct inode *inode, struct file *file)
1378{
Eric W. Biederman426b5302008-01-24 00:13:18 -08001379 return seq_open_net(inode, file, &arp_seq_ops,
1380 sizeof(struct neigh_seq_state));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381}
1382
Arjan van de Ven9a321442007-02-12 00:55:35 -08001383static const struct file_operations arp_seq_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 .owner = THIS_MODULE,
1385 .open = arp_seq_open,
1386 .read = seq_read,
1387 .llseek = seq_lseek,
Eric W. Biederman426b5302008-01-24 00:13:18 -08001388 .release = seq_release_net,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389};
1390
Denis V. Lunevffc31d32008-03-24 15:28:43 -07001391
1392static int __net_init arp_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393{
Gao fengd4beaa62013-02-18 01:34:54 +00001394 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 return -ENOMEM;
1396 return 0;
1397}
1398
Denis V. Lunevffc31d32008-03-24 15:28:43 -07001399static void __net_exit arp_net_exit(struct net *net)
1400{
Gao fengece31ff2013-02-18 01:34:56 +00001401 remove_proc_entry("arp", net->proc_net);
Denis V. Lunevffc31d32008-03-24 15:28:43 -07001402}
1403
1404static struct pernet_operations arp_net_ops = {
1405 .init = arp_net_init,
1406 .exit = arp_net_exit,
1407};
1408
1409static int __init arp_proc_init(void)
1410{
1411 return register_pernet_subsys(&arp_net_ops);
1412}
1413
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414#else /* CONFIG_PROC_FS */
1415
1416static int __init arp_proc_init(void)
1417{
1418 return 0;
1419}
1420
1421#endif /* CONFIG_PROC_FS */