1 /* linux/net/inet/arp.c
3 * Version: $Id: arp.c,v 1.1.1.1 2005/04/11 02:51:13 jack 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.
71 #include <linux/types.h>
72 #include <linux/string.h>
73 #include <linux/kernel.h>
74 #include <linux/sched.h>
75 #include <linux/config.h>
76 #include <linux/socket.h>
77 #include <linux/sockios.h>
78 #include <linux/errno.h>
81 #include <linux/inet.h>
82 #include <linux/netdevice.h>
83 #include <linux/etherdevice.h>
84 #include <linux/fddidevice.h>
85 #include <linux/if_arp.h>
86 #include <linux/trdevice.h>
87 #include <linux/skbuff.h>
88 #include <linux/proc_fs.h>
89 #include <linux/stat.h>
90 #include <linux/init.h>
92 #include <linux/sysctl.h>
97 #include <net/route.h>
98 #include <net/protocol.h>
100 #include <net/sock.h>
102 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
103 #include <net/ax25.h>
104 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
105 #include <net/netrom.h>
108 #ifdef CONFIG_ATM_CLIP
109 #include <net/atmclip.h>
112 #include <asm/system.h>
113 #include <asm/uaccess.h>
115 #include <linux/netfilter_arp.h>
118 * Interface to generic neighbour cache.
120 static u32 arp_hash(const void *pkey, const struct net_device *dev);
121 static int arp_constructor(struct neighbour *neigh);
122 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
123 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
124 static void parp_redo(struct sk_buff *skb);
126 static struct neigh_ops arp_generic_ops = {
128 solicit: arp_solicit,
129 error_report: arp_error_report,
130 output: neigh_resolve_output,
131 connected_output: neigh_connected_output,
132 hh_output: dev_queue_xmit,
133 queue_xmit: dev_queue_xmit,
136 static struct neigh_ops arp_hh_ops = {
138 solicit: arp_solicit,
139 error_report: arp_error_report,
140 output: neigh_resolve_output,
141 connected_output: neigh_resolve_output,
142 hh_output: dev_queue_xmit,
143 queue_xmit: dev_queue_xmit,
146 static struct neigh_ops arp_direct_ops = {
148 output: dev_queue_xmit,
149 connected_output: dev_queue_xmit,
150 hh_output: dev_queue_xmit,
151 queue_xmit: dev_queue_xmit,
154 struct neigh_ops arp_broken_ops = {
156 solicit: arp_solicit,
157 error_report: arp_error_report,
158 output: neigh_compat_output,
159 connected_output: neigh_compat_output,
160 hh_output: dev_queue_xmit,
161 queue_xmit: dev_queue_xmit,
164 struct neigh_table arp_tbl = {
166 entry_size: sizeof(struct neighbour) + 4,
169 constructor: arp_constructor,
170 proxy_redo: parp_redo,
174 base_reachable_time: 30 * HZ,
175 retrans_time: 1 * HZ,
176 gc_staletime: 60 * HZ,
177 reachable_time: 30 * HZ,
178 delay_probe_time: 5 * HZ,
182 anycast_delay: 1 * HZ,
183 proxy_delay: (8 * HZ) / 10,
187 gc_interval: 30 * HZ,
193 int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir)
199 ip_eth_mc_map(addr, haddr);
201 case ARPHRD_IEEE802_TR:
202 ip_tr_mc_map(addr, haddr);
206 memcpy(haddr, dev->broadcast, dev->addr_len);
214 static u32 arp_hash(const void *pkey, const struct net_device *dev)
218 hash_val = *(u32*)pkey;
219 hash_val ^= (hash_val>>16);
220 hash_val ^= hash_val>>8;
221 hash_val ^= hash_val>>3;
222 hash_val = (hash_val^dev->ifindex)&NEIGH_HASHMASK;
227 static int arp_constructor(struct neighbour *neigh)
229 u32 addr = *(u32*)neigh->primary_key;
230 struct net_device *dev = neigh->dev;
231 struct in_device *in_dev = in_dev_get(dev);
236 neigh->type = inet_addr_type(addr);
237 if (in_dev->arp_parms)
238 neigh->parms = in_dev->arp_parms;
242 if (dev->hard_header == NULL) {
243 neigh->nud_state = NUD_NOARP;
244 neigh->ops = &arp_direct_ops;
245 neigh->output = neigh->ops->queue_xmit;
247 /* Good devices (checked by reading texts, but only Ethernet is
250 ARPHRD_ETHER: (ethernet, apfddi)
253 ARPHRD_METRICOM: (strip)
257 ARPHRD_IPDDP will also work, if author repairs it.
258 I did not it, because this driver does not work even
263 /* So... these "amateur" devices are hopeless.
264 The only thing, that I can say now:
265 It is very sad that we need to keep ugly obsolete
266 code to make them happy.
268 They should be moved to more reasonable state, now
269 they use rebuild_header INSTEAD OF hard_start_xmit!!!
270 Besides that, they are sort of out of date
271 (a lot of redundant clones/copies, useless in 2.1),
272 I wonder why people believe that they work.
278 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
280 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
283 neigh->ops = &arp_broken_ops;
284 neigh->output = neigh->ops->output;
289 if (neigh->type == RTN_MULTICAST) {
290 neigh->nud_state = NUD_NOARP;
291 arp_mc_map(addr, neigh->ha, dev, 1);
292 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
293 neigh->nud_state = NUD_NOARP;
294 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
295 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) {
296 neigh->nud_state = NUD_NOARP;
297 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
299 if (dev->hard_header_cache)
300 neigh->ops = &arp_hh_ops;
302 neigh->ops = &arp_generic_ops;
303 if (neigh->nud_state&NUD_VALID)
304 neigh->output = neigh->ops->connected_output;
306 neigh->output = neigh->ops->output;
311 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
313 dst_link_failure(skb);
317 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
321 struct net_device *dev = neigh->dev;
322 u32 target = *(u32*)neigh->primary_key;
323 int probes = atomic_read(&neigh->probes);
325 if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL)
326 saddr = skb->nh.iph->saddr;
328 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
330 if ((probes -= neigh->parms->ucast_probes) < 0) {
331 if (!(neigh->nud_state&NUD_VALID))
332 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
334 read_lock_bh(&neigh->lock);
335 } else if ((probes -= neigh->parms->app_probes) < 0) {
342 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
343 dst_ha, dev->dev_addr, NULL);
345 read_unlock_bh(&neigh->lock);
348 static int arp_filter(__u32 sip, __u32 tip, struct net_device *dev)
352 /*unsigned long now; */
354 if (ip_route_output(&rt, sip, tip, 0, 0) < 0)
356 if (rt->u.dst.dev != dev) {
357 NET_INC_STATS_BH(ArpFilter);
364 /* OBSOLETE FUNCTIONS */
367 * Find an arp mapping in the cache. If not found, post a request.
369 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
370 * even if it exists. It is supposed that skb->dev was mangled
371 * by a virtual device (eql, shaper). Nobody but broken devices
372 * is allowed to use this function, it is scheduled to be removed. --ANK
375 static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev)
379 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
380 memcpy(haddr, dev->dev_addr, dev->addr_len);
383 arp_mc_map(paddr, haddr, dev, 1);
386 memcpy(haddr, dev->broadcast, dev->addr_len);
393 int arp_find(unsigned char *haddr, struct sk_buff *skb)
395 struct net_device *dev = skb->dev;
400 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
405 paddr = ((struct rtable*)skb->dst)->rt_gateway;
407 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev))
410 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
414 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) {
415 read_lock_bh(&n->lock);
416 memcpy(haddr, n->ha, dev->addr_len);
417 read_unlock_bh(&n->lock);
427 /* END OF OBSOLETE FUNCTIONS */
429 int arp_bind_neighbour(struct dst_entry *dst)
431 struct net_device *dev = dst->dev;
432 struct neighbour *n = dst->neighbour;
437 u32 nexthop = ((struct rtable*)dst)->rt_gateway;
438 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT))
440 n = __neigh_lookup_errno(
441 #ifdef CONFIG_ATM_CLIP
442 dev->type == ARPHRD_ATM ? &clip_tbl :
444 &arp_tbl, &nexthop, dev);
453 * Check if we can use proxy ARP for this path
456 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
458 struct in_device *out_dev;
461 if (!IN_DEV_PROXY_ARP(in_dev))
464 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0)
469 /* place to check for proxy_arp for routes */
471 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) {
472 omi = IN_DEV_MEDIUM_ID(out_dev);
475 return (omi != imi && omi != -1);
479 * Interface to link layer: send routine and receive handler.
483 * Create and send an arp packet. If (dest_hw == NULL), we create a broadcast
487 void arp_send(int type, int ptype, u32 dest_ip,
488 struct net_device *dev, u32 src_ip,
489 unsigned char *dest_hw, unsigned char *src_hw,
490 unsigned char *target_hw)
494 unsigned char *arp_ptr;
497 * No arp on this interface.
500 if (dev->flags&IFF_NOARP)
507 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4)
508 + dev->hard_header_len + 15, GFP_ATOMIC);
512 skb_reserve(skb, (dev->hard_header_len+15)&~15);
513 skb->nh.raw = skb->data;
514 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4));
516 skb->protocol = htons (ETH_P_ARP);
518 src_hw = dev->dev_addr;
520 dest_hw = dev->broadcast;
523 * Fill the device header for the ARP frame
525 if (dev->hard_header &&
526 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0)
530 * Fill out the arp protocol part.
532 * The arp hardware type should match the device type, except for FDDI,
533 * which (according to RFC 1390) should always equal 1 (Ethernet).
536 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
537 * DIX code for the protocol. Make these device structure fields.
541 arp->ar_hrd = htons(dev->type);
542 arp->ar_pro = htons(ETH_P_IP);
545 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
547 arp->ar_hrd = htons(ARPHRD_AX25);
548 arp->ar_pro = htons(AX25_P_IP);
551 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
553 arp->ar_hrd = htons(ARPHRD_NETROM);
554 arp->ar_pro = htons(AX25_P_IP);
561 arp->ar_hrd = htons(ARPHRD_ETHER);
562 arp->ar_pro = htons(ETH_P_IP);
566 case ARPHRD_IEEE802_TR:
567 arp->ar_hrd = htons(ARPHRD_IEEE802);
568 arp->ar_pro = htons(ETH_P_IP);
573 arp->ar_hln = dev->addr_len;
575 arp->ar_op = htons(type);
577 arp_ptr=(unsigned char *)(arp+1);
579 memcpy(arp_ptr, src_hw, dev->addr_len);
580 arp_ptr+=dev->addr_len;
581 memcpy(arp_ptr, &src_ip,4);
583 if (target_hw != NULL)
584 memcpy(arp_ptr, target_hw, dev->addr_len);
586 memset(arp_ptr, 0, dev->addr_len);
587 arp_ptr+=dev->addr_len;
588 memcpy(arp_ptr, &dest_ip, 4);
590 /* Send it off, maybe filter it using firewalling first. */
591 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, dev, dev_queue_xmit);
598 static void parp_redo(struct sk_buff *skb)
600 arp_rcv(skb, skb->dev, NULL);
604 * Process an arp request.
607 int arp_process(struct sk_buff *skb)
609 struct net_device *dev = skb->dev;
610 struct in_device *in_dev = in_dev_get(dev);
612 unsigned char *arp_ptr;
614 unsigned char *sha, *tha;
616 u16 dev_type = dev->type;
620 /* arp_rcv below verifies the ARP header, verifies the device
621 * is ARP'able, and linearizes the SKB (if needed).
628 arp_ptr= (unsigned char *)(arp+1);
632 if (arp->ar_pro != htons(ETH_P_IP))
634 if (htons(dev_type) != arp->ar_hrd)
637 #ifdef CONFIG_NET_ETHERNET
640 * ETHERNET devices will accept ARP hardware types of either
641 * 1 (Ethernet) or 6 (IEEE 802.2).
643 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
644 arp->ar_hrd != htons(ARPHRD_IEEE802))
646 if (arp->ar_pro != htons(ETH_P_IP))
651 case ARPHRD_IEEE802_TR:
653 * Token ring devices will accept ARP hardware types of either
654 * 1 (Ethernet) or 6 (IEEE 802.2).
656 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
657 arp->ar_hrd != htons(ARPHRD_IEEE802))
659 if (arp->ar_pro != htons(ETH_P_IP))
666 * According to RFC 1390, FDDI devices should accept ARP hardware types
667 * of 1 (Ethernet). However, to be more robust, we'll accept hardware
668 * types of either 1 (Ethernet) or 6 (IEEE 802.2).
670 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
671 arp->ar_hrd != htons(ARPHRD_IEEE802))
673 if (arp->ar_pro != htons(ETH_P_IP))
680 * According to RFC 2625, Fibre Channel devices (which are IEEE
681 * 802 devices) should accept ARP hardware types of 6 (IEEE 802)
684 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
685 arp->ar_hrd != htons(ARPHRD_IEEE802))
687 if (arp->ar_pro != htons(ETH_P_IP))
691 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
693 if (arp->ar_pro != htons(AX25_P_IP))
695 if (arp->ar_hrd != htons(ARPHRD_AX25))
698 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
700 if (arp->ar_pro != htons(AX25_P_IP))
702 if (arp->ar_hrd != htons(ARPHRD_NETROM))
709 /* Understand only these message types */
711 if (arp->ar_op != htons(ARPOP_REPLY) &&
712 arp->ar_op != htons(ARPOP_REQUEST))
719 arp_ptr += dev->addr_len;
720 memcpy(&sip, arp_ptr, 4);
723 arp_ptr += dev->addr_len;
724 memcpy(&tip, arp_ptr, 4);
726 * Check for bad requests for 127.x.x.x and requests for multicast
727 * addresses. If this is one such, delete it.
729 if (LOOPBACK(tip) || MULTICAST(tip))
733 * Special case: We must set Frame Relay source Q.922 address
735 if (dev_type == ARPHRD_DLCI)
736 sha = dev->broadcast;
739 * Process entry. The idea here is we want to send a reply if it is a
740 * request for us or if it is a request for someone else that we hold
741 * a proxy for. We want to add an entry to our cache if it is a reply
742 * to us or if it is a request for our address.
743 * (The assumption for this last is that if someone is requesting our
744 * address, they are probably intending to talk to us, so it saves time
745 * if we cache their address. Their address is also probably not in
746 * our cache, since ours is not in their cache.)
748 * Putting this another way, we only care about replies if they are to
749 * us, in which case we add them to the cache. For requests, we care
750 * about those for us and those for our proxies. We reply to both,
751 * and in the case of requests for us we add the requester to the arp
755 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
757 if (arp->ar_op == htons(ARPOP_REQUEST) &&
758 inet_addr_type(tip) == RTN_LOCAL)
759 arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr);
763 if (arp->ar_op == htons(ARPOP_REQUEST) &&
764 ip_route_input(skb, tip, sip, 0, dev) == 0) {
766 rt = (struct rtable*)skb->dst;
767 addr_type = rt->rt_type;
769 if (addr_type == RTN_LOCAL) {
770 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
773 if (IN_DEV_ARPFILTER(in_dev))
774 dont_send |= arp_filter(sip,tip,dev);
776 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
781 } else if (IN_DEV_FORWARD(in_dev)) {
782 if ((rt->rt_flags&RTCF_DNAT) ||
783 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev &&
784 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) {
785 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
789 if (skb->stamp.tv_sec == 0 ||
790 skb->pkt_type == PACKET_HOST ||
791 in_dev->arp_parms->proxy_delay == 0) {
792 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
794 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb);
803 /* Update our ARP tables */
805 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
807 #ifdef CONFIG_IP_ACCEPT_UNSOLICITED_ARP
808 /* Unsolicited ARP is not accepted by default.
809 It is possible, that this option should be enabled for some
810 devices (strip is candidate)
813 arp->ar_op == htons(ARPOP_REPLY) &&
814 inet_addr_type(sip) == RTN_UNICAST)
815 n = __neigh_lookup(&arp_tbl, &sip, dev, -1);
819 int state = NUD_REACHABLE;
822 /* If several different ARP replies follows back-to-back,
823 use the FIRST one. It is possible, if several proxy
824 agents are active. Taking the first reply prevents
825 arp trashing and chooses the fastest router.
827 if (jiffies - n->updated >= n->parms->locktime)
830 /* Broadcast replies and request packets
831 do not assert neighbour reachability.
833 if (arp->ar_op != htons(ARPOP_REPLY) ||
834 skb->pkt_type != PACKET_HOST)
836 neigh_update(n, sha, state, override, 1);
849 * Receive an arp request from the device layer.
852 int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
854 struct arphdr *arp = skb->nh.arph;
856 if (arp->ar_hln != dev->addr_len ||
857 dev->flags & IFF_NOARP ||
858 skb->pkt_type == PACKET_OTHERHOST ||
859 skb->pkt_type == PACKET_LOOPBACK ||
863 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
866 if (skb_is_nonlinear(skb)) {
867 if (skb_linearize(skb, GFP_ATOMIC) != 0)
871 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
880 * User level interface (ioctl, /proc)
884 * Set (create) an ARP cache entry.
887 int arp_req_set(struct arpreq *r, struct net_device * dev)
889 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
890 struct neighbour *neigh;
893 if (r->arp_flags&ATF_PUBL) {
894 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
895 if (mask && mask != 0xFFFFFFFF)
897 if (!dev && (r->arp_flags & ATF_COM)) {
898 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data);
903 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL)
908 ipv4_devconf.proxy_arp = 1;
911 if (__in_dev_get(dev)) {
912 __in_dev_get(dev)->cnf.proxy_arp = 1;
918 if (r->arp_flags & ATF_PERM)
919 r->arp_flags |= ATF_COM;
922 if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
929 if (r->arp_ha.sa_family != dev->type)
932 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
933 err = PTR_ERR(neigh);
934 if (!IS_ERR(neigh)) {
935 unsigned state = NUD_STALE;
936 if (r->arp_flags & ATF_PERM)
937 state = NUD_PERMANENT;
938 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
939 r->arp_ha.sa_data : NULL, state, 1, 0);
940 neigh_release(neigh);
945 static unsigned arp_state_to_flags(struct neighbour *neigh)
948 if (neigh->nud_state&NUD_PERMANENT)
949 flags = ATF_PERM|ATF_COM;
950 else if (neigh->nud_state&NUD_VALID)
956 * Get an ARP cache entry.
959 static int arp_req_get(struct arpreq *r, struct net_device *dev)
961 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
962 struct neighbour *neigh;
965 neigh = neigh_lookup(&arp_tbl, &ip, dev);
967 read_lock_bh(&neigh->lock);
968 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
969 r->arp_flags = arp_state_to_flags(neigh);
970 read_unlock_bh(&neigh->lock);
971 r->arp_ha.sa_family = dev->type;
972 strncpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
973 neigh_release(neigh);
979 int arp_req_delete(struct arpreq *r, struct net_device * dev)
982 u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
983 struct neighbour *neigh;
985 if (r->arp_flags & ATF_PUBL) {
986 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
987 if (mask == 0xFFFFFFFF)
988 return pneigh_delete(&arp_tbl, &ip, dev);
991 ipv4_devconf.proxy_arp = 0;
994 if (__in_dev_get(dev)) {
995 __in_dev_get(dev)->cnf.proxy_arp = 0;
1005 if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
1007 dev = rt->u.dst.dev;
1013 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1015 if (neigh->nud_state&~NUD_NOARP)
1016 err = neigh_update(neigh, NULL, NUD_FAILED, 1, 0);
1017 neigh_release(neigh);
1023 * Handle an ARP layer I/O control request.
1026 int arp_ioctl(unsigned int cmd, void *arg)
1030 struct net_device * dev = NULL;
1035 if (!capable(CAP_NET_ADMIN))
1038 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1046 if (r.arp_pa.sa_family != AF_INET)
1047 return -EPFNOSUPPORT;
1049 if (!(r.arp_flags & ATF_PUBL) &&
1050 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
1052 if (!(r.arp_flags & ATF_NETMASK))
1053 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr=htonl(0xFFFFFFFFUL);
1058 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL)
1061 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1062 if (!r.arp_ha.sa_family)
1063 r.arp_ha.sa_family = dev->type;
1065 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1067 } else if (cmd == SIOCGARP) {
1074 err = arp_req_delete(&r, dev);
1077 err = arp_req_set(&r, dev);
1080 err = arp_req_get(&r, dev);
1081 if (!err && copy_to_user(arg, &r, sizeof(r)))
1091 * Write the contents of the ARP cache to a PROCfs file.
1093 #ifndef CONFIG_PROC_FS
1094 static int arp_get_info(char *buffer, char **start, off_t offset, int length) { return 0; }
1096 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1097 static char *ax2asc2(ax25_address *a, char *buf);
1099 #define HBUFFERLEN 30
1101 static int arp_get_info(char *buffer, char **start, off_t offset, int length)
1106 char hbuffer[HBUFFERLEN];
1108 const char hexbuf[] = "0123456789ABCDEF";
1110 size = sprintf(buffer,"IP address HW type Flags HW address Mask Device\n");
1115 for(i=0; i<=NEIGH_HASHMASK; i++) {
1116 struct neighbour *n;
1117 read_lock_bh(&arp_tbl.lock);
1118 for (n=arp_tbl.hash_buckets[i]; n; n=n->next) {
1119 struct net_device *dev = n->dev;
1120 int hatype = dev->type;
1122 /* Do not confuse users "arp -a" with magic entries */
1123 if (!(n->nud_state&~NUD_NOARP))
1126 read_lock(&n->lock);
1129 * Convert hardware address to XX:XX:XX:XX ... form.
1131 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1132 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1133 ax2asc2((ax25_address *)n->ha, hbuffer);
1136 for (k=0,j=0;k<HBUFFERLEN-3 && j<dev->addr_len;j++) {
1137 hbuffer[k++]=hexbuf[(n->ha[j]>>4)&15 ];
1138 hbuffer[k++]=hexbuf[n->ha[j]&15 ];
1143 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1149 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key));
1150 size = sprintf(buffer+len, "%-16s 0x%-10x0x%-10x%s"
1154 arp_state_to_flags(n),
1159 read_unlock(&n->lock);
1166 if (pos >= offset+length) {
1167 read_unlock_bh(&arp_tbl.lock);
1171 read_unlock_bh(&arp_tbl.lock);
1174 for (i=0; i<=PNEIGH_HASHMASK; i++) {
1175 struct pneigh_entry *n;
1176 for (n=arp_tbl.phash_buckets[i]; n; n=n->next) {
1177 struct net_device *dev = n->dev;
1178 int hatype = dev ? dev->type : 0;
1182 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key));
1183 size = sprintf(buffer+len, "%-16s 0x%-10x0x%-10x%s"
1188 "00:00:00:00:00:00",
1189 dev ? dev->name : "*");
1197 if (pos >= offset+length)
1204 *start = buffer+len-(pos-offset); /* Start of wanted data */
1205 len = pos-offset; /* Start slop */
1207 len = length; /* Ending slop */
1214 /* Note, that it is not on notifier chain.
1215 It is necessary, that this routine was called after route cache will be
1218 void arp_ifdown(struct net_device *dev)
1220 neigh_ifdown(&arp_tbl, dev);
1225 * Called once on startup.
1228 static struct packet_type arp_packet_type = {
1229 type: __constant_htons(ETH_P_ARP),
1231 data: (void*) 1, /* understand shared skbs */
1234 void __init arp_init (void)
1236 neigh_table_init(&arp_tbl);
1238 dev_add_pack(&arp_packet_type);
1240 proc_net_create ("arp", 0, arp_get_info);
1242 #ifdef CONFIG_SYSCTL
1243 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, NET_IPV4_NEIGH, "ipv4");
1248 #ifdef CONFIG_PROC_FS
1249 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1252 * ax25 -> ASCII conversion
1254 char *ax2asc2(ax25_address *a, char *buf)
1259 for (n = 0, s = buf; n < 6; n++) {
1260 c = (a->ax25_call[n] >> 1) & 0x7F;
1262 if (c != ' ') *s++ = c;
1267 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
1275 if (*buf == '\0' || *buf == '-')