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>
107 #include <net/icmp.h>
108 #include <net/route.h>
109 #include <net/protocol.h>
111 #include <net/sock.h>
113 #include <net/ax25.h>
114 #include <net/netrom.h>
115 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
116 #include <net/atmclip.h>
117 struct neigh_table
*clip_tbl_hook
;
120 #include <asm/system.h>
121 #include <asm/uaccess.h>
123 #include <linux/netfilter_arp.h>
126 * Interface to generic neighbour cache.
128 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
);
129 static int arp_constructor(struct neighbour
*neigh
);
130 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
);
131 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
);
132 static void parp_redo(struct sk_buff
*skb
);
134 static struct neigh_ops arp_generic_ops
= {
136 .solicit
= arp_solicit
,
137 .error_report
= arp_error_report
,
138 .output
= neigh_resolve_output
,
139 .connected_output
= neigh_connected_output
,
140 .hh_output
= dev_queue_xmit
,
141 .queue_xmit
= dev_queue_xmit
,
144 static struct neigh_ops arp_hh_ops
= {
146 .solicit
= arp_solicit
,
147 .error_report
= arp_error_report
,
148 .output
= neigh_resolve_output
,
149 .connected_output
= neigh_resolve_output
,
150 .hh_output
= dev_queue_xmit
,
151 .queue_xmit
= dev_queue_xmit
,
154 static struct neigh_ops arp_direct_ops
= {
156 .output
= dev_queue_xmit
,
157 .connected_output
= dev_queue_xmit
,
158 .hh_output
= dev_queue_xmit
,
159 .queue_xmit
= dev_queue_xmit
,
162 struct neigh_ops arp_broken_ops
= {
164 .solicit
= arp_solicit
,
165 .error_report
= arp_error_report
,
166 .output
= neigh_compat_output
,
167 .connected_output
= neigh_compat_output
,
168 .hh_output
= dev_queue_xmit
,
169 .queue_xmit
= dev_queue_xmit
,
172 struct neigh_table arp_tbl
= {
174 .entry_size
= sizeof(struct neighbour
) + 4,
177 .constructor
= arp_constructor
,
178 .proxy_redo
= parp_redo
,
182 .base_reachable_time
= 30 * HZ
,
183 .retrans_time
= 1 * HZ
,
184 .gc_staletime
= 60 * HZ
,
185 .reachable_time
= 30 * HZ
,
186 .delay_probe_time
= 5 * HZ
,
190 .anycast_delay
= 1 * HZ
,
191 .proxy_delay
= (8 * HZ
) / 10,
195 .gc_interval
= 30 * HZ
,
201 int arp_mc_map(__be32 addr
, u8
*haddr
, struct net_device
*dev
, int dir
)
207 ip_eth_mc_map(addr
, haddr
);
209 case ARPHRD_IEEE802_TR
:
210 ip_tr_mc_map(addr
, haddr
);
212 case ARPHRD_INFINIBAND
:
213 ip_ib_mc_map(addr
, haddr
);
217 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
225 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
)
227 return jhash_2words(*(u32
*)pkey
, dev
->ifindex
, arp_tbl
.hash_rnd
);
230 static int arp_constructor(struct neighbour
*neigh
)
232 __be32 addr
= *(__be32
*)neigh
->primary_key
;
233 struct net_device
*dev
= neigh
->dev
;
234 struct in_device
*in_dev
;
235 struct neigh_parms
*parms
;
237 neigh
->type
= inet_addr_type(addr
);
240 in_dev
= __in_dev_get_rcu(dev
);
241 if (in_dev
== NULL
) {
246 parms
= in_dev
->arp_parms
;
247 __neigh_parms_put(neigh
->parms
);
248 neigh
->parms
= neigh_parms_clone(parms
);
251 if (dev
->hard_header
== NULL
) {
252 neigh
->nud_state
= NUD_NOARP
;
253 neigh
->ops
= &arp_direct_ops
;
254 neigh
->output
= neigh
->ops
->queue_xmit
;
256 /* Good devices (checked by reading texts, but only Ethernet is
259 ARPHRD_ETHER: (ethernet, apfddi)
262 ARPHRD_METRICOM: (strip)
266 ARPHRD_IPDDP will also work, if author repairs it.
267 I did not it, because this driver does not work even
272 /* So... these "amateur" devices are hopeless.
273 The only thing, that I can say now:
274 It is very sad that we need to keep ugly obsolete
275 code to make them happy.
277 They should be moved to more reasonable state, now
278 they use rebuild_header INSTEAD OF hard_start_xmit!!!
279 Besides that, they are sort of out of date
280 (a lot of redundant clones/copies, useless in 2.1),
281 I wonder why people believe that they work.
287 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
289 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
292 neigh
->ops
= &arp_broken_ops
;
293 neigh
->output
= neigh
->ops
->output
;
298 if (neigh
->type
== RTN_MULTICAST
) {
299 neigh
->nud_state
= NUD_NOARP
;
300 arp_mc_map(addr
, neigh
->ha
, dev
, 1);
301 } else if (dev
->flags
&(IFF_NOARP
|IFF_LOOPBACK
)) {
302 neigh
->nud_state
= NUD_NOARP
;
303 memcpy(neigh
->ha
, dev
->dev_addr
, dev
->addr_len
);
304 } else if (neigh
->type
== RTN_BROADCAST
|| dev
->flags
&IFF_POINTOPOINT
) {
305 neigh
->nud_state
= NUD_NOARP
;
306 memcpy(neigh
->ha
, dev
->broadcast
, dev
->addr_len
);
308 if (dev
->hard_header_cache
)
309 neigh
->ops
= &arp_hh_ops
;
311 neigh
->ops
= &arp_generic_ops
;
312 if (neigh
->nud_state
&NUD_VALID
)
313 neigh
->output
= neigh
->ops
->connected_output
;
315 neigh
->output
= neigh
->ops
->output
;
320 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
)
322 dst_link_failure(skb
);
326 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
)
330 struct net_device
*dev
= neigh
->dev
;
331 __be32 target
= *(__be32
*)neigh
->primary_key
;
332 int probes
= atomic_read(&neigh
->probes
);
333 struct in_device
*in_dev
= in_dev_get(dev
);
338 switch (IN_DEV_ARP_ANNOUNCE(in_dev
)) {
340 case 0: /* By default announce any local IP */
341 if (skb
&& inet_addr_type(ip_hdr(skb
)->saddr
) == RTN_LOCAL
)
342 saddr
= ip_hdr(skb
)->saddr
;
344 case 1: /* Restrict announcements of saddr in same subnet */
347 saddr
= ip_hdr(skb
)->saddr
;
348 if (inet_addr_type(saddr
) == RTN_LOCAL
) {
349 /* saddr should be known to target */
350 if (inet_addr_onlink(in_dev
, target
, saddr
))
355 case 2: /* Avoid secondary IPs, get a primary/preferred one */
362 saddr
= inet_select_addr(dev
, target
, RT_SCOPE_LINK
);
364 if ((probes
-= neigh
->parms
->ucast_probes
) < 0) {
365 if (!(neigh
->nud_state
&NUD_VALID
))
366 printk(KERN_DEBUG
"trying to ucast probe in NUD_INVALID\n");
368 read_lock_bh(&neigh
->lock
);
369 } else if ((probes
-= neigh
->parms
->app_probes
) < 0) {
376 arp_send(ARPOP_REQUEST
, ETH_P_ARP
, target
, dev
, saddr
,
377 dst_ha
, dev
->dev_addr
, NULL
);
379 read_unlock_bh(&neigh
->lock
);
382 static int arp_ignore(struct in_device
*in_dev
, struct net_device
*dev
,
383 __be32 sip
, __be32 tip
)
387 switch (IN_DEV_ARP_IGNORE(in_dev
)) {
388 case 0: /* Reply, the tip is already validated */
390 case 1: /* Reply only if tip is configured on the incoming interface */
392 scope
= RT_SCOPE_HOST
;
395 * Reply only if tip is configured on the incoming interface
396 * and is in same subnet as sip
398 scope
= RT_SCOPE_HOST
;
400 case 3: /* Do not reply for scope host addresses */
402 scope
= RT_SCOPE_LINK
;
405 case 4: /* Reserved */
410 case 8: /* Do not reply */
415 return !inet_confirm_addr(dev
, sip
, tip
, scope
);
418 static int arp_filter(__be32 sip
, __be32 tip
, struct net_device
*dev
)
420 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= sip
,
424 /*unsigned long now; */
426 if (ip_route_output_key(&rt
, &fl
) < 0)
428 if (rt
->u
.dst
.dev
!= dev
) {
429 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER
);
436 /* OBSOLETE FUNCTIONS */
439 * Find an arp mapping in the cache. If not found, post a request.
441 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
442 * even if it exists. It is supposed that skb->dev was mangled
443 * by a virtual device (eql, shaper). Nobody but broken devices
444 * is allowed to use this function, it is scheduled to be removed. --ANK
447 static int arp_set_predefined(int addr_hint
, unsigned char * haddr
, __be32 paddr
, struct net_device
* dev
)
451 printk(KERN_DEBUG
"ARP: arp called for own IP address\n");
452 memcpy(haddr
, dev
->dev_addr
, dev
->addr_len
);
455 arp_mc_map(paddr
, haddr
, dev
, 1);
458 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
465 int arp_find(unsigned char *haddr
, struct sk_buff
*skb
)
467 struct net_device
*dev
= skb
->dev
;
472 printk(KERN_DEBUG
"arp_find is called with dst==NULL\n");
477 paddr
= ((struct rtable
*)skb
->dst
)->rt_gateway
;
479 if (arp_set_predefined(inet_addr_type(paddr
), haddr
, paddr
, dev
))
482 n
= __neigh_lookup(&arp_tbl
, &paddr
, dev
, 1);
486 if (n
->nud_state
&NUD_VALID
|| neigh_event_send(n
, skb
) == 0) {
487 read_lock_bh(&n
->lock
);
488 memcpy(haddr
, n
->ha
, dev
->addr_len
);
489 read_unlock_bh(&n
->lock
);
499 /* END OF OBSOLETE FUNCTIONS */
501 int arp_bind_neighbour(struct dst_entry
*dst
)
503 struct net_device
*dev
= dst
->dev
;
504 struct neighbour
*n
= dst
->neighbour
;
509 __be32 nexthop
= ((struct rtable
*)dst
)->rt_gateway
;
510 if (dev
->flags
&(IFF_LOOPBACK
|IFF_POINTOPOINT
))
512 n
= __neigh_lookup_errno(
513 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
514 dev
->type
== ARPHRD_ATM
? clip_tbl_hook
:
516 &arp_tbl
, &nexthop
, dev
);
525 * Check if we can use proxy ARP for this path
528 static inline int arp_fwd_proxy(struct in_device
*in_dev
, struct rtable
*rt
)
530 struct in_device
*out_dev
;
533 if (!IN_DEV_PROXY_ARP(in_dev
))
536 if ((imi
= IN_DEV_MEDIUM_ID(in_dev
)) == 0)
541 /* place to check for proxy_arp for routes */
543 if ((out_dev
= in_dev_get(rt
->u
.dst
.dev
)) != NULL
) {
544 omi
= IN_DEV_MEDIUM_ID(out_dev
);
547 return (omi
!= imi
&& omi
!= -1);
551 * Interface to link layer: send routine and receive handler.
555 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
558 struct sk_buff
*arp_create(int type
, int ptype
, __be32 dest_ip
,
559 struct net_device
*dev
, __be32 src_ip
,
560 unsigned char *dest_hw
, unsigned char *src_hw
,
561 unsigned char *target_hw
)
565 unsigned char *arp_ptr
;
571 skb
= alloc_skb(sizeof(struct arphdr
)+ 2*(dev
->addr_len
+4)
572 + LL_RESERVED_SPACE(dev
), GFP_ATOMIC
);
576 skb_reserve(skb
, LL_RESERVED_SPACE(dev
));
577 skb_reset_network_header(skb
);
578 arp
= (struct arphdr
*) skb_put(skb
,sizeof(struct arphdr
) + 2*(dev
->addr_len
+4));
580 skb
->protocol
= htons(ETH_P_ARP
);
582 src_hw
= dev
->dev_addr
;
584 dest_hw
= dev
->broadcast
;
587 * Fill the device header for the ARP frame
589 if (dev
->hard_header
&&
590 dev
->hard_header(skb
,dev
,ptype
,dest_hw
,src_hw
,skb
->len
) < 0)
594 * Fill out the arp protocol part.
596 * The arp hardware type should match the device type, except for FDDI,
597 * which (according to RFC 1390) should always equal 1 (Ethernet).
600 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
601 * DIX code for the protocol. Make these device structure fields.
605 arp
->ar_hrd
= htons(dev
->type
);
606 arp
->ar_pro
= htons(ETH_P_IP
);
609 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
611 arp
->ar_hrd
= htons(ARPHRD_AX25
);
612 arp
->ar_pro
= htons(AX25_P_IP
);
615 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
617 arp
->ar_hrd
= htons(ARPHRD_NETROM
);
618 arp
->ar_pro
= htons(AX25_P_IP
);
625 arp
->ar_hrd
= htons(ARPHRD_ETHER
);
626 arp
->ar_pro
= htons(ETH_P_IP
);
630 case ARPHRD_IEEE802_TR
:
631 arp
->ar_hrd
= htons(ARPHRD_IEEE802
);
632 arp
->ar_pro
= htons(ETH_P_IP
);
637 arp
->ar_hln
= dev
->addr_len
;
639 arp
->ar_op
= htons(type
);
641 arp_ptr
=(unsigned char *)(arp
+1);
643 memcpy(arp_ptr
, src_hw
, dev
->addr_len
);
644 arp_ptr
+=dev
->addr_len
;
645 memcpy(arp_ptr
, &src_ip
,4);
647 if (target_hw
!= NULL
)
648 memcpy(arp_ptr
, target_hw
, dev
->addr_len
);
650 memset(arp_ptr
, 0, dev
->addr_len
);
651 arp_ptr
+=dev
->addr_len
;
652 memcpy(arp_ptr
, &dest_ip
, 4);
662 * Send an arp packet.
664 void arp_xmit(struct sk_buff
*skb
)
666 /* Send it off, maybe filter it using firewalling first. */
667 NF_HOOK(NF_ARP
, NF_ARP_OUT
, skb
, NULL
, skb
->dev
, dev_queue_xmit
);
671 * Create and send an arp packet.
673 void arp_send(int type
, int ptype
, __be32 dest_ip
,
674 struct net_device
*dev
, __be32 src_ip
,
675 unsigned char *dest_hw
, unsigned char *src_hw
,
676 unsigned char *target_hw
)
681 * No arp on this interface.
684 if (dev
->flags
&IFF_NOARP
)
687 skb
= arp_create(type
, ptype
, dest_ip
, dev
, src_ip
,
688 dest_hw
, src_hw
, target_hw
);
697 * Process an arp request.
700 static int arp_process(struct sk_buff
*skb
)
702 struct net_device
*dev
= skb
->dev
;
703 struct in_device
*in_dev
= in_dev_get(dev
);
705 unsigned char *arp_ptr
;
707 unsigned char *sha
, *tha
;
709 u16 dev_type
= dev
->type
;
713 /* arp_rcv below verifies the ARP header and verifies the device
724 if (arp
->ar_pro
!= htons(ETH_P_IP
) ||
725 htons(dev_type
) != arp
->ar_hrd
)
729 case ARPHRD_IEEE802_TR
:
733 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
734 * devices, according to RFC 2625) devices will accept ARP
735 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
736 * This is the case also of FDDI, where the RFC 1390 says that
737 * FDDI devices should accept ARP hardware of (1) Ethernet,
738 * however, to be more robust, we'll accept both 1 (Ethernet)
741 if ((arp
->ar_hrd
!= htons(ARPHRD_ETHER
) &&
742 arp
->ar_hrd
!= htons(ARPHRD_IEEE802
)) ||
743 arp
->ar_pro
!= htons(ETH_P_IP
))
747 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
748 arp
->ar_hrd
!= htons(ARPHRD_AX25
))
752 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
753 arp
->ar_hrd
!= htons(ARPHRD_NETROM
))
758 /* Understand only these message types */
760 if (arp
->ar_op
!= htons(ARPOP_REPLY
) &&
761 arp
->ar_op
!= htons(ARPOP_REQUEST
))
767 arp_ptr
= (unsigned char *)(arp
+1);
769 arp_ptr
+= dev
->addr_len
;
770 memcpy(&sip
, arp_ptr
, 4);
773 arp_ptr
+= dev
->addr_len
;
774 memcpy(&tip
, arp_ptr
, 4);
776 * Check for bad requests for 127.x.x.x and requests for multicast
777 * addresses. If this is one such, delete it.
779 if (LOOPBACK(tip
) || MULTICAST(tip
))
783 * Special case: We must set Frame Relay source Q.922 address
785 if (dev_type
== ARPHRD_DLCI
)
786 sha
= dev
->broadcast
;
789 * Process entry. The idea here is we want to send a reply if it is a
790 * request for us or if it is a request for someone else that we hold
791 * a proxy for. We want to add an entry to our cache if it is a reply
792 * to us or if it is a request for our address.
793 * (The assumption for this last is that if someone is requesting our
794 * address, they are probably intending to talk to us, so it saves time
795 * if we cache their address. Their address is also probably not in
796 * our cache, since ours is not in their cache.)
798 * Putting this another way, we only care about replies if they are to
799 * us, in which case we add them to the cache. For requests, we care
800 * about those for us and those for our proxies. We reply to both,
801 * and in the case of requests for us we add the requester to the arp
805 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
807 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
808 inet_addr_type(tip
) == RTN_LOCAL
&&
809 !arp_ignore(in_dev
,dev
,sip
,tip
))
810 arp_send(ARPOP_REPLY
,ETH_P_ARP
,tip
,dev
,tip
,sha
,dev
->dev_addr
,dev
->dev_addr
);
814 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
815 ip_route_input(skb
, tip
, sip
, 0, dev
) == 0) {
817 rt
= (struct rtable
*)skb
->dst
;
818 addr_type
= rt
->rt_type
;
820 if (addr_type
== RTN_LOCAL
) {
821 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
826 dont_send
|= arp_ignore(in_dev
,dev
,sip
,tip
);
827 if (!dont_send
&& IN_DEV_ARPFILTER(in_dev
))
828 dont_send
|= arp_filter(sip
,tip
,dev
);
830 arp_send(ARPOP_REPLY
,ETH_P_ARP
,sip
,dev
,tip
,sha
,dev
->dev_addr
,sha
);
835 } else if (IN_DEV_FORWARD(in_dev
)) {
836 if ((rt
->rt_flags
&RTCF_DNAT
) ||
837 (addr_type
== RTN_UNICAST
&& rt
->u
.dst
.dev
!= dev
&&
838 (arp_fwd_proxy(in_dev
, rt
) || pneigh_lookup(&arp_tbl
, &tip
, dev
, 0)))) {
839 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
843 if (NEIGH_CB(skb
)->flags
& LOCALLY_ENQUEUED
||
844 skb
->pkt_type
== PACKET_HOST
||
845 in_dev
->arp_parms
->proxy_delay
== 0) {
846 arp_send(ARPOP_REPLY
,ETH_P_ARP
,sip
,dev
,tip
,sha
,dev
->dev_addr
,sha
);
848 pneigh_enqueue(&arp_tbl
, in_dev
->arp_parms
, skb
);
857 /* Update our ARP tables */
859 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 0);
861 if (IPV4_DEVCONF_ALL(ARP_ACCEPT
)) {
862 /* Unsolicited ARP is not accepted by default.
863 It is possible, that this option should be enabled for some
864 devices (strip is candidate)
867 arp
->ar_op
== htons(ARPOP_REPLY
) &&
868 inet_addr_type(sip
) == RTN_UNICAST
)
869 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, -1);
873 int state
= NUD_REACHABLE
;
876 /* If several different ARP replies follows back-to-back,
877 use the FIRST one. It is possible, if several proxy
878 agents are active. Taking the first reply prevents
879 arp trashing and chooses the fastest router.
881 override
= time_after(jiffies
, n
->updated
+ n
->parms
->locktime
);
883 /* Broadcast replies and request packets
884 do not assert neighbour reachability.
886 if (arp
->ar_op
!= htons(ARPOP_REPLY
) ||
887 skb
->pkt_type
!= PACKET_HOST
)
889 neigh_update(n
, sha
, state
, override
? NEIGH_UPDATE_F_OVERRIDE
: 0);
900 static void parp_redo(struct sk_buff
*skb
)
907 * Receive an arp request from the device layer.
910 static int arp_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
911 struct packet_type
*pt
, struct net_device
*orig_dev
)
915 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
916 if (!pskb_may_pull(skb
, (sizeof(struct arphdr
) +
917 (2 * dev
->addr_len
) +
922 if (arp
->ar_hln
!= dev
->addr_len
||
923 dev
->flags
& IFF_NOARP
||
924 skb
->pkt_type
== PACKET_OTHERHOST
||
925 skb
->pkt_type
== PACKET_LOOPBACK
||
929 if ((skb
= skb_share_check(skb
, GFP_ATOMIC
)) == NULL
)
932 memset(NEIGH_CB(skb
), 0, sizeof(struct neighbour_cb
));
934 return NF_HOOK(NF_ARP
, NF_ARP_IN
, skb
, dev
, NULL
, arp_process
);
943 * User level interface (ioctl)
947 * Set (create) an ARP cache entry.
950 static int arp_req_set(struct arpreq
*r
, struct net_device
* dev
)
952 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
953 struct neighbour
*neigh
;
956 if (r
->arp_flags
&ATF_PUBL
) {
957 __be32 mask
= ((struct sockaddr_in
*) &r
->arp_netmask
)->sin_addr
.s_addr
;
958 if (mask
&& mask
!= htonl(0xFFFFFFFF))
960 if (!dev
&& (r
->arp_flags
& ATF_COM
)) {
961 dev
= dev_getbyhwaddr(r
->arp_ha
.sa_family
, r
->arp_ha
.sa_data
);
966 if (pneigh_lookup(&arp_tbl
, &ip
, dev
, 1) == NULL
)
971 IPV4_DEVCONF_ALL(PROXY_ARP
) = 1;
974 if (__in_dev_get_rtnl(dev
)) {
975 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev
), PROXY_ARP
, 1);
981 if (r
->arp_flags
& ATF_PERM
)
982 r
->arp_flags
|= ATF_COM
;
984 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= ip
,
985 .tos
= RTO_ONLINK
} } };
987 if ((err
= ip_route_output_key(&rt
, &fl
)) != 0)
998 * According to RFC 1390, FDDI devices should accept ARP
999 * hardware types of 1 (Ethernet). However, to be more
1000 * robust, we'll accept hardware types of either 1 (Ethernet)
1001 * or 6 (IEEE 802.2).
1003 if (r
->arp_ha
.sa_family
!= ARPHRD_FDDI
&&
1004 r
->arp_ha
.sa_family
!= ARPHRD_ETHER
&&
1005 r
->arp_ha
.sa_family
!= ARPHRD_IEEE802
)
1010 if (r
->arp_ha
.sa_family
!= dev
->type
)
1015 neigh
= __neigh_lookup_errno(&arp_tbl
, &ip
, dev
);
1016 err
= PTR_ERR(neigh
);
1017 if (!IS_ERR(neigh
)) {
1018 unsigned state
= NUD_STALE
;
1019 if (r
->arp_flags
& ATF_PERM
)
1020 state
= NUD_PERMANENT
;
1021 err
= neigh_update(neigh
, (r
->arp_flags
&ATF_COM
) ?
1022 r
->arp_ha
.sa_data
: NULL
, state
,
1023 NEIGH_UPDATE_F_OVERRIDE
|
1024 NEIGH_UPDATE_F_ADMIN
);
1025 neigh_release(neigh
);
1030 static unsigned arp_state_to_flags(struct neighbour
*neigh
)
1033 if (neigh
->nud_state
&NUD_PERMANENT
)
1034 flags
= ATF_PERM
|ATF_COM
;
1035 else if (neigh
->nud_state
&NUD_VALID
)
1041 * Get an ARP cache entry.
1044 static int arp_req_get(struct arpreq
*r
, struct net_device
*dev
)
1046 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1047 struct neighbour
*neigh
;
1050 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1052 read_lock_bh(&neigh
->lock
);
1053 memcpy(r
->arp_ha
.sa_data
, neigh
->ha
, dev
->addr_len
);
1054 r
->arp_flags
= arp_state_to_flags(neigh
);
1055 read_unlock_bh(&neigh
->lock
);
1056 r
->arp_ha
.sa_family
= dev
->type
;
1057 strlcpy(r
->arp_dev
, dev
->name
, sizeof(r
->arp_dev
));
1058 neigh_release(neigh
);
1064 static int arp_req_delete(struct arpreq
*r
, struct net_device
* dev
)
1067 __be32 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1068 struct neighbour
*neigh
;
1070 if (r
->arp_flags
& ATF_PUBL
) {
1072 ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1073 if (mask
== htonl(0xFFFFFFFF))
1074 return pneigh_delete(&arp_tbl
, &ip
, dev
);
1077 IPV4_DEVCONF_ALL(PROXY_ARP
) = 0;
1080 if (__in_dev_get_rtnl(dev
)) {
1081 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev
),
1091 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= ip
,
1092 .tos
= RTO_ONLINK
} } };
1094 if ((err
= ip_route_output_key(&rt
, &fl
)) != 0)
1096 dev
= rt
->u
.dst
.dev
;
1102 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1104 if (neigh
->nud_state
&~NUD_NOARP
)
1105 err
= neigh_update(neigh
, NULL
, NUD_FAILED
,
1106 NEIGH_UPDATE_F_OVERRIDE
|
1107 NEIGH_UPDATE_F_ADMIN
);
1108 neigh_release(neigh
);
1114 * Handle an ARP layer I/O control request.
1117 int arp_ioctl(unsigned int cmd
, void __user
*arg
)
1121 struct net_device
*dev
= NULL
;
1126 if (!capable(CAP_NET_ADMIN
))
1129 err
= copy_from_user(&r
, arg
, sizeof(struct arpreq
));
1137 if (r
.arp_pa
.sa_family
!= AF_INET
)
1138 return -EPFNOSUPPORT
;
1140 if (!(r
.arp_flags
& ATF_PUBL
) &&
1141 (r
.arp_flags
& (ATF_NETMASK
|ATF_DONTPUB
)))
1143 if (!(r
.arp_flags
& ATF_NETMASK
))
1144 ((struct sockaddr_in
*)&r
.arp_netmask
)->sin_addr
.s_addr
=
1145 htonl(0xFFFFFFFFUL
);
1149 if ((dev
= __dev_get_by_name(r
.arp_dev
)) == NULL
)
1152 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1153 if (!r
.arp_ha
.sa_family
)
1154 r
.arp_ha
.sa_family
= dev
->type
;
1156 if ((r
.arp_flags
& ATF_COM
) && r
.arp_ha
.sa_family
!= dev
->type
)
1158 } else if (cmd
== SIOCGARP
) {
1165 err
= arp_req_delete(&r
, dev
);
1168 err
= arp_req_set(&r
, dev
);
1171 err
= arp_req_get(&r
, dev
);
1172 if (!err
&& copy_to_user(arg
, &r
, sizeof(r
)))
1181 static int arp_netdev_event(struct notifier_block
*this, unsigned long event
, void *ptr
)
1183 struct net_device
*dev
= ptr
;
1186 case NETDEV_CHANGEADDR
:
1187 neigh_changeaddr(&arp_tbl
, dev
);
1197 static struct notifier_block arp_netdev_notifier
= {
1198 .notifier_call
= arp_netdev_event
,
1201 /* Note, that it is not on notifier chain.
1202 It is necessary, that this routine was called after route cache will be
1205 void arp_ifdown(struct net_device
*dev
)
1207 neigh_ifdown(&arp_tbl
, dev
);
1212 * Called once on startup.
1215 static struct packet_type arp_packet_type
= {
1216 .type
= __constant_htons(ETH_P_ARP
),
1220 static int arp_proc_init(void);
1222 void __init
arp_init(void)
1224 neigh_table_init(&arp_tbl
);
1226 dev_add_pack(&arp_packet_type
);
1228 #ifdef CONFIG_SYSCTL
1229 neigh_sysctl_register(NULL
, &arp_tbl
.parms
, NET_IPV4
,
1230 NET_IPV4_NEIGH
, "ipv4", NULL
, NULL
);
1232 register_netdevice_notifier(&arp_netdev_notifier
);
1235 #ifdef CONFIG_PROC_FS
1236 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1238 /* ------------------------------------------------------------------------ */
1240 * ax25 -> ASCII conversion
1242 static char *ax2asc2(ax25_address
*a
, char *buf
)
1247 for (n
= 0, s
= buf
; n
< 6; n
++) {
1248 c
= (a
->ax25_call
[n
] >> 1) & 0x7F;
1250 if (c
!= ' ') *s
++ = c
;
1255 if ((n
= ((a
->ax25_call
[6] >> 1) & 0x0F)) > 9) {
1263 if (*buf
== '\0' || *buf
== '-')
1269 #endif /* CONFIG_AX25 */
1271 #define HBUFFERLEN 30
1273 static void arp_format_neigh_entry(struct seq_file
*seq
,
1274 struct neighbour
*n
)
1276 char hbuffer
[HBUFFERLEN
];
1277 const char hexbuf
[] = "0123456789ABCDEF";
1280 struct net_device
*dev
= n
->dev
;
1281 int hatype
= dev
->type
;
1283 read_lock(&n
->lock
);
1284 /* Convert hardware address to XX:XX:XX:XX ... form. */
1285 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1286 if (hatype
== ARPHRD_AX25
|| hatype
== ARPHRD_NETROM
)
1287 ax2asc2((ax25_address
*)n
->ha
, hbuffer
);
1290 for (k
= 0, j
= 0; k
< HBUFFERLEN
- 3 && j
< dev
->addr_len
; j
++) {
1291 hbuffer
[k
++] = hexbuf
[(n
->ha
[j
] >> 4) & 15];
1292 hbuffer
[k
++] = hexbuf
[n
->ha
[j
] & 15];
1296 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1299 sprintf(tbuf
, "%u.%u.%u.%u", NIPQUAD(*(u32
*)n
->primary_key
));
1300 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1301 tbuf
, hatype
, arp_state_to_flags(n
), hbuffer
, dev
->name
);
1302 read_unlock(&n
->lock
);
1305 static void arp_format_pneigh_entry(struct seq_file
*seq
,
1306 struct pneigh_entry
*n
)
1308 struct net_device
*dev
= n
->dev
;
1309 int hatype
= dev
? dev
->type
: 0;
1312 sprintf(tbuf
, "%u.%u.%u.%u", NIPQUAD(*(u32
*)n
->key
));
1313 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1314 tbuf
, hatype
, ATF_PUBL
| ATF_PERM
, "00:00:00:00:00:00",
1315 dev
? dev
->name
: "*");
1318 static int arp_seq_show(struct seq_file
*seq
, void *v
)
1320 if (v
== SEQ_START_TOKEN
) {
1321 seq_puts(seq
, "IP address HW type Flags "
1322 "HW address Mask Device\n");
1324 struct neigh_seq_state
*state
= seq
->private;
1326 if (state
->flags
& NEIGH_SEQ_IS_PNEIGH
)
1327 arp_format_pneigh_entry(seq
, v
);
1329 arp_format_neigh_entry(seq
, v
);
1335 static void *arp_seq_start(struct seq_file
*seq
, loff_t
*pos
)
1337 /* Don't want to confuse "arp -a" w/ magic entries,
1338 * so we tell the generic iterator to skip NUD_NOARP.
1340 return neigh_seq_start(seq
, pos
, &arp_tbl
, NEIGH_SEQ_SKIP_NOARP
);
1343 /* ------------------------------------------------------------------------ */
1345 static const struct seq_operations arp_seq_ops
= {
1346 .start
= arp_seq_start
,
1347 .next
= neigh_seq_next
,
1348 .stop
= neigh_seq_stop
,
1349 .show
= arp_seq_show
,
1352 static int arp_seq_open(struct inode
*inode
, struct file
*file
)
1354 struct seq_file
*seq
;
1356 struct neigh_seq_state
*s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
1361 rc
= seq_open(file
, &arp_seq_ops
);
1365 seq
= file
->private_data
;
1374 static const struct file_operations arp_seq_fops
= {
1375 .owner
= THIS_MODULE
,
1376 .open
= arp_seq_open
,
1378 .llseek
= seq_lseek
,
1379 .release
= seq_release_private
,
1382 static int __init
arp_proc_init(void)
1384 if (!proc_net_fops_create("arp", S_IRUGO
, &arp_seq_fops
))
1389 #else /* CONFIG_PROC_FS */
1391 static int __init
arp_proc_init(void)
1396 #endif /* CONFIG_PROC_FS */
1398 EXPORT_SYMBOL(arp_broken_ops
);
1399 EXPORT_SYMBOL(arp_find
);
1400 EXPORT_SYMBOL(arp_create
);
1401 EXPORT_SYMBOL(arp_xmit
);
1402 EXPORT_SYMBOL(arp_send
);
1403 EXPORT_SYMBOL(arp_tbl
);
1405 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
1406 EXPORT_SYMBOL(clip_tbl_hook
);