1 /* linux/net/ipv4/arp.c
3 * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $
5 * Copyright (C) 1994 by Florian La Roche
7 * This module implements the Address Resolution Protocol ARP (RFC 826),
8 * which is used to convert IP addresses (or in the future maybe other
9 * high-level addresses) into a low-level hardware address (like an Ethernet
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
18 * Alan Cox : Removed the Ethernet assumptions in
20 * Alan Cox : Fixed some small errors in the ARP
22 * Alan Cox : Allow >4K in /proc
23 * Alan Cox : Make ARP add its own protocol entry
24 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
25 * Stephen Henson : Add AX25 support to arp_get_info()
26 * Alan Cox : Drop data when a device is downed.
27 * Alan Cox : Use init_timer().
28 * Alan Cox : Double lock fixes.
29 * Martin Seine : Move the arphdr structure
30 * to if_arp.h for compatibility.
31 * with BSD based programs.
32 * Andrew Tridgell : Added ARP netmask code and
33 * re-arranged proxy handling.
34 * Alan Cox : Changed to use notifiers.
35 * Niibe Yutaka : Reply for this device or proxies only.
36 * Alan Cox : Don't proxy across hardware types!
37 * Jonathan Naylor : Added support for NET/ROM.
38 * Mike Shaver : RFC1122 checks.
39 * Jonathan Naylor : Only lookup the hardware address for
40 * the correct hardware type.
41 * Germano Caronni : Assorted subtle races.
42 * Craig Schlenter : Don't modify permanent entry
44 * Russ Nelson : Tidied up a few bits.
45 * Alexey Kuznetsov: Major changes to caching and behaviour,
46 * eg intelligent arp probing and
48 * of host down events.
49 * Alan Cox : Missing unlock in device events.
50 * Eckes : ARP ioctl control errors.
51 * Alexey Kuznetsov: Arp free fix.
52 * Manuel Rodriguez: Gratuitous ARP.
53 * Jonathan Layes : Added arpd support through kerneld
54 * message queue (960314)
55 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
56 * Mike McLagan : Routing by source
57 * Stuart Cheshire : Metricom and grat arp fixes
58 * *** FOR 2.1 clean this up ***
59 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
60 * Alan Cox : Took the AP1000 nasty FDDI hack and
61 * folded into the mainstream FDDI code.
62 * Ack spit, Linus how did you allow that
64 * Jes Sorensen : Make FDDI work again in 2.1.x and
65 * clean up the APFDDI & gen. FDDI bits.
66 * Alexey Kuznetsov: new arp state machine;
67 * now it is in net/core/neighbour.c.
68 * Krzysztof Halasa: Added Frame Relay ARP support.
69 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
70 * Shmulik Hen: Split arp_send to arp_create and
71 * arp_xmit so intermediate drivers like
72 * bonding can change the skb before
73 * sending (e.g. insert 8021q tag).
74 * Harald Welte : convert to make use of jenkins hash
77 #include <linux/module.h>
78 #include <linux/types.h>
79 #include <linux/string.h>
80 #include <linux/kernel.h>
81 #include <linux/capability.h>
82 #include <linux/socket.h>
83 #include <linux/sockios.h>
84 #include <linux/errno.h>
87 #include <linux/inet.h>
88 #include <linux/inetdevice.h>
89 #include <linux/netdevice.h>
90 #include <linux/etherdevice.h>
91 #include <linux/fddidevice.h>
92 #include <linux/if_arp.h>
93 #include <linux/trdevice.h>
94 #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>
101 #include <linux/jhash.h>
103 #include <linux/sysctl.h>
106 #include <net/net_namespace.h>
108 #include <net/icmp.h>
109 #include <net/route.h>
110 #include <net/protocol.h>
112 #include <net/sock.h>
114 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
115 #include <net/ax25.h>
116 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
117 #include <net/netrom.h>
120 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
121 #include <net/atmclip.h>
122 struct neigh_table *clip_tbl_hook;
125 #include <asm/system.h>
126 #include <asm/uaccess.h>
128 #include <linux/netfilter_arp.h>
131 * Interface to generic neighbour cache.
133 static u32 arp_hash(const void *pkey, const struct net_device *dev);
134 static int arp_constructor(struct neighbour *neigh);
135 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
136 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
137 static void parp_redo(struct sk_buff *skb);
139 static struct neigh_ops arp_generic_ops = {
141 .solicit = arp_solicit,
142 .error_report = arp_error_report,
143 .output = neigh_resolve_output,
144 .connected_output = neigh_connected_output,
145 .hh_output = dev_queue_xmit,
146 .queue_xmit = dev_queue_xmit,
149 static struct neigh_ops arp_hh_ops = {
151 .solicit = arp_solicit,
152 .error_report = arp_error_report,
153 .output = neigh_resolve_output,
154 .connected_output = neigh_resolve_output,
155 .hh_output = dev_queue_xmit,
156 .queue_xmit = dev_queue_xmit,
159 static struct neigh_ops arp_direct_ops = {
161 .output = dev_queue_xmit,
162 .connected_output = dev_queue_xmit,
163 .hh_output = dev_queue_xmit,
164 .queue_xmit = dev_queue_xmit,
167 struct neigh_ops arp_broken_ops = {
169 .solicit = arp_solicit,
170 .error_report = arp_error_report,
171 .output = neigh_compat_output,
172 .connected_output = neigh_compat_output,
173 .hh_output = dev_queue_xmit,
174 .queue_xmit = dev_queue_xmit,
177 struct neigh_table arp_tbl = {
179 .entry_size = sizeof(struct neighbour) + 4,
182 .constructor = arp_constructor,
183 .proxy_redo = parp_redo,
187 .base_reachable_time = 30 * HZ,
188 .retrans_time = 1 * HZ,
189 .gc_staletime = 60 * HZ,
190 .reachable_time = 30 * HZ,
191 .delay_probe_time = 5 * HZ,
195 .anycast_delay = 1 * HZ,
196 .proxy_delay = (8 * HZ) / 10,
200 .gc_interval = 30 * HZ,
206 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
212 ip_eth_mc_map(addr, haddr);
214 case ARPHRD_IEEE802_TR:
215 ip_tr_mc_map(addr, haddr);
217 case ARPHRD_INFINIBAND:
218 ip_ib_mc_map(addr, haddr);
222 memcpy(haddr, dev->broadcast, dev->addr_len);
230 static u32 arp_hash(const void *pkey, const struct net_device *dev)
232 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd);
235 static int arp_constructor(struct neighbour *neigh)
237 __be32 addr = *(__be32*)neigh->primary_key;
238 struct net_device *dev = neigh->dev;
239 struct in_device *in_dev;
240 struct neigh_parms *parms;
242 neigh->type = inet_addr_type(addr);
245 in_dev = __in_dev_get_rcu(dev);
246 if (in_dev == NULL) {
251 parms = in_dev->arp_parms;
252 __neigh_parms_put(neigh->parms);
253 neigh->parms = neigh_parms_clone(parms);
256 if (dev->hard_header == NULL) {
257 neigh->nud_state = NUD_NOARP;
258 neigh->ops = &arp_direct_ops;
259 neigh->output = neigh->ops->queue_xmit;
261 /* Good devices (checked by reading texts, but only Ethernet is
264 ARPHRD_ETHER: (ethernet, apfddi)
267 ARPHRD_METRICOM: (strip)
271 ARPHRD_IPDDP will also work, if author repairs it.
272 I did not it, because this driver does not work even
277 /* So... these "amateur" devices are hopeless.
278 The only thing, that I can say now:
279 It is very sad that we need to keep ugly obsolete
280 code to make them happy.
282 They should be moved to more reasonable state, now
283 they use rebuild_header INSTEAD OF hard_start_xmit!!!
284 Besides that, they are sort of out of date
285 (a lot of redundant clones/copies, useless in 2.1),
286 I wonder why people believe that they work.
292 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
294 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
297 neigh->ops = &arp_broken_ops;
298 neigh->output = neigh->ops->output;
303 if (neigh->type == RTN_MULTICAST) {
304 neigh->nud_state = NUD_NOARP;
305 arp_mc_map(addr, neigh->ha, dev, 1);
306 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
307 neigh->nud_state = NUD_NOARP;
308 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
309 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) {
310 neigh->nud_state = NUD_NOARP;
311 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
313 if (dev->hard_header_cache)
314 neigh->ops = &arp_hh_ops;
316 neigh->ops = &arp_generic_ops;
317 if (neigh->nud_state&NUD_VALID)
318 neigh->output = neigh->ops->connected_output;
320 neigh->output = neigh->ops->output;
325 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
327 dst_link_failure(skb);
331 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
335 struct net_device *dev = neigh->dev;
336 __be32 target = *(__be32*)neigh->primary_key;
337 int probes = atomic_read(&neigh->probes);
338 struct in_device *in_dev = in_dev_get(dev);
343 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
345 case 0: /* By default announce any local IP */
346 if (skb && inet_addr_type(ip_hdr(skb)->saddr) == RTN_LOCAL)
347 saddr = ip_hdr(skb)->saddr;
349 case 1: /* Restrict announcements of saddr in same subnet */
352 saddr = ip_hdr(skb)->saddr;
353 if (inet_addr_type(saddr) == RTN_LOCAL) {
354 /* saddr should be known to target */
355 if (inet_addr_onlink(in_dev, target, saddr))
360 case 2: /* Avoid secondary IPs, get a primary/preferred one */
367 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
369 if ((probes -= neigh->parms->ucast_probes) < 0) {
370 if (!(neigh->nud_state&NUD_VALID))
371 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
373 read_lock_bh(&neigh->lock);
374 } else if ((probes -= neigh->parms->app_probes) < 0) {
381 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
382 dst_ha, dev->dev_addr, NULL);
384 read_unlock_bh(&neigh->lock);
387 static int arp_ignore(struct in_device *in_dev, struct net_device *dev,
388 __be32 sip, __be32 tip)
392 switch (IN_DEV_ARP_IGNORE(in_dev)) {
393 case 0: /* Reply, the tip is already validated */
395 case 1: /* Reply only if tip is configured on the incoming interface */
397 scope = RT_SCOPE_HOST;
400 * Reply only if tip is configured on the incoming interface
401 * and is in same subnet as sip
403 scope = RT_SCOPE_HOST;
405 case 3: /* Do not reply for scope host addresses */
407 scope = RT_SCOPE_LINK;
410 case 4: /* Reserved */
415 case 8: /* Do not reply */
420 return !inet_confirm_addr(dev, sip, tip, scope);
423 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
425 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip,
429 /*unsigned long now; */
431 if (ip_route_output_key(&rt, &fl) < 0)
433 if (rt->u.dst.dev != dev) {
434 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER);
441 /* OBSOLETE FUNCTIONS */
444 * Find an arp mapping in the cache. If not found, post a request.
446 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
447 * even if it exists. It is supposed that skb->dev was mangled
448 * by a virtual device (eql, shaper). Nobody but broken devices
449 * is allowed to use this function, it is scheduled to be removed. --ANK
452 static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 paddr, struct net_device * dev)
456 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
457 memcpy(haddr, dev->dev_addr, dev->addr_len);
460 arp_mc_map(paddr, haddr, dev, 1);
463 memcpy(haddr, dev->broadcast, dev->addr_len);
470 int arp_find(unsigned char *haddr, struct sk_buff *skb)
472 struct net_device *dev = skb->dev;
477 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
482 paddr = ((struct rtable*)skb->dst)->rt_gateway;
484 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev))
487 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
491 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) {
492 read_lock_bh(&n->lock);
493 memcpy(haddr, n->ha, dev->addr_len);
494 read_unlock_bh(&n->lock);
504 /* END OF OBSOLETE FUNCTIONS */
506 int arp_bind_neighbour(struct dst_entry *dst)
508 struct net_device *dev = dst->dev;
509 struct neighbour *n = dst->neighbour;
514 __be32 nexthop = ((struct rtable*)dst)->rt_gateway;
515 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT))
517 n = __neigh_lookup_errno(
518 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
519 dev->type == ARPHRD_ATM ? clip_tbl_hook :
521 &arp_tbl, &nexthop, dev);
530 * Check if we can use proxy ARP for this path
533 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
535 struct in_device *out_dev;
538 if (!IN_DEV_PROXY_ARP(in_dev))
541 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0)
546 /* place to check for proxy_arp for routes */
548 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) {
549 omi = IN_DEV_MEDIUM_ID(out_dev);
552 return (omi != imi && omi != -1);
556 * Interface to link layer: send routine and receive handler.
560 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
563 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
564 struct net_device *dev, __be32 src_ip,
565 unsigned char *dest_hw, unsigned char *src_hw,
566 unsigned char *target_hw)
570 unsigned char *arp_ptr;
576 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4)
577 + LL_RESERVED_SPACE(dev), GFP_ATOMIC);
581 skb_reserve(skb, LL_RESERVED_SPACE(dev));
582 skb_reset_network_header(skb);
583 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4));
585 skb->protocol = htons(ETH_P_ARP);
587 src_hw = dev->dev_addr;
589 dest_hw = dev->broadcast;
592 * Fill the device header for the ARP frame
594 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
598 * Fill out the arp protocol part.
600 * The arp hardware type should match the device type, except for FDDI,
601 * which (according to RFC 1390) should always equal 1 (Ethernet).
604 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
605 * DIX code for the protocol. Make these device structure fields.
609 arp->ar_hrd = htons(dev->type);
610 arp->ar_pro = htons(ETH_P_IP);
613 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
615 arp->ar_hrd = htons(ARPHRD_AX25);
616 arp->ar_pro = htons(AX25_P_IP);
619 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
621 arp->ar_hrd = htons(ARPHRD_NETROM);
622 arp->ar_pro = htons(AX25_P_IP);
629 arp->ar_hrd = htons(ARPHRD_ETHER);
630 arp->ar_pro = htons(ETH_P_IP);
634 case ARPHRD_IEEE802_TR:
635 arp->ar_hrd = htons(ARPHRD_IEEE802);
636 arp->ar_pro = htons(ETH_P_IP);
641 arp->ar_hln = dev->addr_len;
643 arp->ar_op = htons(type);
645 arp_ptr=(unsigned char *)(arp+1);
647 memcpy(arp_ptr, src_hw, dev->addr_len);
648 arp_ptr+=dev->addr_len;
649 memcpy(arp_ptr, &src_ip,4);
651 if (target_hw != NULL)
652 memcpy(arp_ptr, target_hw, dev->addr_len);
654 memset(arp_ptr, 0, dev->addr_len);
655 arp_ptr+=dev->addr_len;
656 memcpy(arp_ptr, &dest_ip, 4);
666 * Send an arp packet.
668 void arp_xmit(struct sk_buff *skb)
670 /* Send it off, maybe filter it using firewalling first. */
671 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
675 * Create and send an arp packet.
677 void arp_send(int type, int ptype, __be32 dest_ip,
678 struct net_device *dev, __be32 src_ip,
679 unsigned char *dest_hw, unsigned char *src_hw,
680 unsigned char *target_hw)
685 * No arp on this interface.
688 if (dev->flags&IFF_NOARP)
691 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
692 dest_hw, src_hw, target_hw);
701 * Process an arp request.
704 static int arp_process(struct sk_buff *skb)
706 struct net_device *dev = skb->dev;
707 struct in_device *in_dev = in_dev_get(dev);
709 unsigned char *arp_ptr;
711 unsigned char *sha, *tha;
713 u16 dev_type = dev->type;
717 /* arp_rcv below verifies the ARP header and verifies the device
728 if (arp->ar_pro != htons(ETH_P_IP) ||
729 htons(dev_type) != arp->ar_hrd)
732 #ifdef CONFIG_NET_ETHERNET
736 case ARPHRD_IEEE802_TR:
744 #if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \
745 defined(CONFIG_FDDI) || defined(CONFIG_NET_FC)
747 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
748 * devices, according to RFC 2625) devices will accept ARP
749 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
750 * This is the case also of FDDI, where the RFC 1390 says that
751 * FDDI devices should accept ARP hardware of (1) Ethernet,
752 * however, to be more robust, we'll accept both 1 (Ethernet)
755 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
756 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
757 arp->ar_pro != htons(ETH_P_IP))
761 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
763 if (arp->ar_pro != htons(AX25_P_IP) ||
764 arp->ar_hrd != htons(ARPHRD_AX25))
767 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
769 if (arp->ar_pro != htons(AX25_P_IP) ||
770 arp->ar_hrd != htons(ARPHRD_NETROM))
777 /* Understand only these message types */
779 if (arp->ar_op != htons(ARPOP_REPLY) &&
780 arp->ar_op != htons(ARPOP_REQUEST))
786 arp_ptr= (unsigned char *)(arp+1);
788 arp_ptr += dev->addr_len;
789 memcpy(&sip, arp_ptr, 4);
792 arp_ptr += dev->addr_len;
793 memcpy(&tip, arp_ptr, 4);
795 * Check for bad requests for 127.x.x.x and requests for multicast
796 * addresses. If this is one such, delete it.
798 if (LOOPBACK(tip) || MULTICAST(tip))
802 * Special case: We must set Frame Relay source Q.922 address
804 if (dev_type == ARPHRD_DLCI)
805 sha = dev->broadcast;
808 * Process entry. The idea here is we want to send a reply if it is a
809 * request for us or if it is a request for someone else that we hold
810 * a proxy for. We want to add an entry to our cache if it is a reply
811 * to us or if it is a request for our address.
812 * (The assumption for this last is that if someone is requesting our
813 * address, they are probably intending to talk to us, so it saves time
814 * if we cache their address. Their address is also probably not in
815 * our cache, since ours is not in their cache.)
817 * Putting this another way, we only care about replies if they are to
818 * us, in which case we add them to the cache. For requests, we care
819 * about those for us and those for our proxies. We reply to both,
820 * and in the case of requests for us we add the requester to the arp
824 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
826 if (arp->ar_op == htons(ARPOP_REQUEST) &&
827 inet_addr_type(tip) == RTN_LOCAL &&
828 !arp_ignore(in_dev,dev,sip,tip))
829 arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr);
833 if (arp->ar_op == htons(ARPOP_REQUEST) &&
834 ip_route_input(skb, tip, sip, 0, dev) == 0) {
836 rt = (struct rtable*)skb->dst;
837 addr_type = rt->rt_type;
839 if (addr_type == RTN_LOCAL) {
840 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
845 dont_send |= arp_ignore(in_dev,dev,sip,tip);
846 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
847 dont_send |= arp_filter(sip,tip,dev);
849 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
854 } else if (IN_DEV_FORWARD(in_dev)) {
855 if ((rt->rt_flags&RTCF_DNAT) ||
856 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev &&
857 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) {
858 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
862 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
863 skb->pkt_type == PACKET_HOST ||
864 in_dev->arp_parms->proxy_delay == 0) {
865 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
867 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb);
876 /* Update our ARP tables */
878 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
880 if (IPV4_DEVCONF_ALL(ARP_ACCEPT)) {
881 /* Unsolicited ARP is not accepted by default.
882 It is possible, that this option should be enabled for some
883 devices (strip is candidate)
886 arp->ar_op == htons(ARPOP_REPLY) &&
887 inet_addr_type(sip) == RTN_UNICAST)
888 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
892 int state = NUD_REACHABLE;
895 /* If several different ARP replies follows back-to-back,
896 use the FIRST one. It is possible, if several proxy
897 agents are active. Taking the first reply prevents
898 arp trashing and chooses the fastest router.
900 override = time_after(jiffies, n->updated + n->parms->locktime);
902 /* Broadcast replies and request packets
903 do not assert neighbour reachability.
905 if (arp->ar_op != htons(ARPOP_REPLY) ||
906 skb->pkt_type != PACKET_HOST)
908 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0);
919 static void parp_redo(struct sk_buff *skb)
926 * Receive an arp request from the device layer.
929 static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
930 struct packet_type *pt, struct net_device *orig_dev)
934 if (dev->nd_net != &init_net)
937 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
938 if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
939 (2 * dev->addr_len) +
944 if (arp->ar_hln != dev->addr_len ||
945 dev->flags & IFF_NOARP ||
946 skb->pkt_type == PACKET_OTHERHOST ||
947 skb->pkt_type == PACKET_LOOPBACK ||
951 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
954 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
956 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
965 * User level interface (ioctl)
969 * Set (create) an ARP cache entry.
972 static int arp_req_set(struct arpreq *r, struct net_device * dev)
974 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
975 struct neighbour *neigh;
978 if (r->arp_flags&ATF_PUBL) {
979 __be32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
980 if (mask && mask != htonl(0xFFFFFFFF))
982 if (!dev && (r->arp_flags & ATF_COM)) {
983 dev = dev_getbyhwaddr(&init_net, r->arp_ha.sa_family, r->arp_ha.sa_data);
988 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL)
993 IPV4_DEVCONF_ALL(PROXY_ARP) = 1;
996 if (__in_dev_get_rtnl(dev)) {
997 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, 1);
1003 if (r->arp_flags & ATF_PERM)
1004 r->arp_flags |= ATF_COM;
1006 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
1007 .tos = RTO_ONLINK } } };
1009 if ((err = ip_route_output_key(&rt, &fl)) != 0)
1011 dev = rt->u.dst.dev;
1016 switch (dev->type) {
1020 * According to RFC 1390, FDDI devices should accept ARP
1021 * hardware types of 1 (Ethernet). However, to be more
1022 * robust, we'll accept hardware types of either 1 (Ethernet)
1023 * or 6 (IEEE 802.2).
1025 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1026 r->arp_ha.sa_family != ARPHRD_ETHER &&
1027 r->arp_ha.sa_family != ARPHRD_IEEE802)
1032 if (r->arp_ha.sa_family != dev->type)
1037 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1038 err = PTR_ERR(neigh);
1039 if (!IS_ERR(neigh)) {
1040 unsigned state = NUD_STALE;
1041 if (r->arp_flags & ATF_PERM)
1042 state = NUD_PERMANENT;
1043 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
1044 r->arp_ha.sa_data : NULL, state,
1045 NEIGH_UPDATE_F_OVERRIDE|
1046 NEIGH_UPDATE_F_ADMIN);
1047 neigh_release(neigh);
1052 static unsigned arp_state_to_flags(struct neighbour *neigh)
1055 if (neigh->nud_state&NUD_PERMANENT)
1056 flags = ATF_PERM|ATF_COM;
1057 else if (neigh->nud_state&NUD_VALID)
1063 * Get an ARP cache entry.
1066 static int arp_req_get(struct arpreq *r, struct net_device *dev)
1068 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1069 struct neighbour *neigh;
1072 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1074 read_lock_bh(&neigh->lock);
1075 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1076 r->arp_flags = arp_state_to_flags(neigh);
1077 read_unlock_bh(&neigh->lock);
1078 r->arp_ha.sa_family = dev->type;
1079 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1080 neigh_release(neigh);
1086 static int arp_req_delete(struct arpreq *r, struct net_device * dev)
1089 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1090 struct neighbour *neigh;
1092 if (r->arp_flags & ATF_PUBL) {
1094 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1095 if (mask == htonl(0xFFFFFFFF))
1096 return pneigh_delete(&arp_tbl, &ip, dev);
1099 IPV4_DEVCONF_ALL(PROXY_ARP) = 0;
1102 if (__in_dev_get_rtnl(dev)) {
1103 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev),
1113 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
1114 .tos = RTO_ONLINK } } };
1116 if ((err = ip_route_output_key(&rt, &fl)) != 0)
1118 dev = rt->u.dst.dev;
1124 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1126 if (neigh->nud_state&~NUD_NOARP)
1127 err = neigh_update(neigh, NULL, NUD_FAILED,
1128 NEIGH_UPDATE_F_OVERRIDE|
1129 NEIGH_UPDATE_F_ADMIN);
1130 neigh_release(neigh);
1136 * Handle an ARP layer I/O control request.
1139 int arp_ioctl(unsigned int cmd, void __user *arg)
1143 struct net_device *dev = NULL;
1148 if (!capable(CAP_NET_ADMIN))
1151 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1159 if (r.arp_pa.sa_family != AF_INET)
1160 return -EPFNOSUPPORT;
1162 if (!(r.arp_flags & ATF_PUBL) &&
1163 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
1165 if (!(r.arp_flags & ATF_NETMASK))
1166 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1167 htonl(0xFFFFFFFFUL);
1171 if ((dev = __dev_get_by_name(&init_net, r.arp_dev)) == NULL)
1174 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1175 if (!r.arp_ha.sa_family)
1176 r.arp_ha.sa_family = dev->type;
1178 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1180 } else if (cmd == SIOCGARP) {
1187 err = arp_req_delete(&r, dev);
1190 err = arp_req_set(&r, dev);
1193 err = arp_req_get(&r, dev);
1194 if (!err && copy_to_user(arg, &r, sizeof(r)))
1203 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1205 struct net_device *dev = ptr;
1207 if (dev->nd_net != &init_net)
1211 case NETDEV_CHANGEADDR:
1212 neigh_changeaddr(&arp_tbl, dev);
1222 static struct notifier_block arp_netdev_notifier = {
1223 .notifier_call = arp_netdev_event,
1226 /* Note, that it is not on notifier chain.
1227 It is necessary, that this routine was called after route cache will be
1230 void arp_ifdown(struct net_device *dev)
1232 neigh_ifdown(&arp_tbl, dev);
1237 * Called once on startup.
1240 static struct packet_type arp_packet_type = {
1241 .type = __constant_htons(ETH_P_ARP),
1245 static int arp_proc_init(void);
1247 void __init arp_init(void)
1249 neigh_table_init(&arp_tbl);
1251 dev_add_pack(&arp_packet_type);
1253 #ifdef CONFIG_SYSCTL
1254 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4,
1255 NET_IPV4_NEIGH, "ipv4", NULL, NULL);
1257 register_netdevice_notifier(&arp_netdev_notifier);
1260 #ifdef CONFIG_PROC_FS
1261 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1263 /* ------------------------------------------------------------------------ */
1265 * ax25 -> ASCII conversion
1267 static char *ax2asc2(ax25_address *a, char *buf)
1272 for (n = 0, s = buf; n < 6; n++) {
1273 c = (a->ax25_call[n] >> 1) & 0x7F;
1275 if (c != ' ') *s++ = c;
1280 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
1288 if (*buf == '\0' || *buf == '-')
1294 #endif /* CONFIG_AX25 */
1296 #define HBUFFERLEN 30
1298 static void arp_format_neigh_entry(struct seq_file *seq,
1299 struct neighbour *n)
1301 char hbuffer[HBUFFERLEN];
1302 const char hexbuf[] = "0123456789ABCDEF";
1305 struct net_device *dev = n->dev;
1306 int hatype = dev->type;
1308 read_lock(&n->lock);
1309 /* Convert hardware address to XX:XX:XX:XX ... form. */
1310 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1311 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1312 ax2asc2((ax25_address *)n->ha, hbuffer);
1315 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1316 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15];
1317 hbuffer[k++] = hexbuf[n->ha[j] & 15];
1321 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1324 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key));
1325 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);
1330 static void arp_format_pneigh_entry(struct seq_file *seq,
1331 struct pneigh_entry *n)
1333 struct net_device *dev = n->dev;
1334 int hatype = dev ? dev->type : 0;
1337 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key));
1338 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 : "*");
1343 static int arp_seq_show(struct seq_file *seq, void *v)
1345 if (v == SEQ_START_TOKEN) {
1346 seq_puts(seq, "IP address HW type Flags "
1347 "HW address Mask Device\n");
1349 struct neigh_seq_state *state = seq->private;
1351 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1352 arp_format_pneigh_entry(seq, v);
1354 arp_format_neigh_entry(seq, v);
1360 static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1362 /* Don't want to confuse "arp -a" w/ magic entries,
1363 * so we tell the generic iterator to skip NUD_NOARP.
1365 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1368 /* ------------------------------------------------------------------------ */
1370 static const struct seq_operations arp_seq_ops = {
1371 .start = arp_seq_start,
1372 .next = neigh_seq_next,
1373 .stop = neigh_seq_stop,
1374 .show = arp_seq_show,
1377 static int arp_seq_open(struct inode *inode, struct file *file)
1379 struct seq_file *seq;
1381 struct neigh_seq_state *s = kzalloc(sizeof(*s), GFP_KERNEL);
1386 rc = seq_open(file, &arp_seq_ops);
1390 seq = file->private_data;
1399 static const struct file_operations arp_seq_fops = {
1400 .owner = THIS_MODULE,
1401 .open = arp_seq_open,
1403 .llseek = seq_lseek,
1404 .release = seq_release_private,
1407 static int __init arp_proc_init(void)
1409 if (!proc_net_fops_create(&init_net, "arp", S_IRUGO, &arp_seq_fops))
1414 #else /* CONFIG_PROC_FS */
1416 static int __init arp_proc_init(void)
1421 #endif /* CONFIG_PROC_FS */
1423 EXPORT_SYMBOL(arp_broken_ops);
1424 EXPORT_SYMBOL(arp_find);
1425 EXPORT_SYMBOL(arp_create);
1426 EXPORT_SYMBOL(arp_xmit);
1427 EXPORT_SYMBOL(arp_send);
1428 EXPORT_SYMBOL(arp_tbl);
1430 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
1431 EXPORT_SYMBOL(clip_tbl_hook);