1 /* linux/net/inet/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/sched.h>
82 #include <linux/config.h>
83 #include <linux/socket.h>
84 #include <linux/sockios.h>
85 #include <linux/errno.h>
88 #include <linux/inet.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 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
114 #include <net/ax25.h>
115 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
116 #include <net/netrom.h>
119 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
120 #include <net/atmclip.h>
121 struct neigh_table
*clip_tbl_hook
;
124 #include <asm/system.h>
125 #include <asm/uaccess.h>
127 #include <linux/netfilter_arp.h>
130 * Interface to generic neighbour cache.
132 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
);
133 static int arp_constructor(struct neighbour
*neigh
);
134 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
);
135 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
);
136 static void parp_redo(struct sk_buff
*skb
);
138 static struct neigh_ops arp_generic_ops
= {
140 .solicit
= arp_solicit
,
141 .error_report
= arp_error_report
,
142 .output
= neigh_resolve_output
,
143 .connected_output
= neigh_connected_output
,
144 .hh_output
= dev_queue_xmit
,
145 .queue_xmit
= dev_queue_xmit
,
148 static struct neigh_ops arp_hh_ops
= {
150 .solicit
= arp_solicit
,
151 .error_report
= arp_error_report
,
152 .output
= neigh_resolve_output
,
153 .connected_output
= neigh_resolve_output
,
154 .hh_output
= dev_queue_xmit
,
155 .queue_xmit
= dev_queue_xmit
,
158 static struct neigh_ops arp_direct_ops
= {
160 .output
= dev_queue_xmit
,
161 .connected_output
= dev_queue_xmit
,
162 .hh_output
= dev_queue_xmit
,
163 .queue_xmit
= dev_queue_xmit
,
166 struct neigh_ops arp_broken_ops
= {
168 .solicit
= arp_solicit
,
169 .error_report
= arp_error_report
,
170 .output
= neigh_compat_output
,
171 .connected_output
= neigh_compat_output
,
172 .hh_output
= dev_queue_xmit
,
173 .queue_xmit
= dev_queue_xmit
,
176 struct neigh_table arp_tbl
= {
178 .entry_size
= sizeof(struct neighbour
) + 4,
181 .constructor
= arp_constructor
,
182 .proxy_redo
= parp_redo
,
186 .base_reachable_time
= 30 * HZ
,
187 .retrans_time
= 1 * HZ
,
188 .gc_staletime
= 60 * HZ
,
189 .reachable_time
= 30 * HZ
,
190 .delay_probe_time
= 5 * HZ
,
194 .anycast_delay
= 1 * HZ
,
195 .proxy_delay
= (8 * HZ
) / 10,
199 .gc_interval
= 30 * HZ
,
205 int arp_mc_map(u32 addr
, u8
*haddr
, struct net_device
*dev
, int dir
)
211 ip_eth_mc_map(addr
, haddr
);
213 case ARPHRD_IEEE802_TR
:
214 ip_tr_mc_map(addr
, haddr
);
218 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
226 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
)
228 return jhash_2words(*(u32
*)pkey
, dev
->ifindex
, arp_tbl
.hash_rnd
);
231 static int arp_constructor(struct neighbour
*neigh
)
233 u32 addr
= *(u32
*)neigh
->primary_key
;
234 struct net_device
*dev
= neigh
->dev
;
235 struct in_device
*in_dev
;
236 struct neigh_parms
*parms
;
238 neigh
->type
= inet_addr_type(addr
);
241 in_dev
= rcu_dereference(__in_dev_get(dev
));
242 if (in_dev
== NULL
) {
247 parms
= in_dev
->arp_parms
;
248 __neigh_parms_put(neigh
->parms
);
249 neigh
->parms
= neigh_parms_clone(parms
);
252 if (dev
->hard_header
== NULL
) {
253 neigh
->nud_state
= NUD_NOARP
;
254 neigh
->ops
= &arp_direct_ops
;
255 neigh
->output
= neigh
->ops
->queue_xmit
;
257 /* Good devices (checked by reading texts, but only Ethernet is
260 ARPHRD_ETHER: (ethernet, apfddi)
263 ARPHRD_METRICOM: (strip)
267 ARPHRD_IPDDP will also work, if author repairs it.
268 I did not it, because this driver does not work even
273 /* So... these "amateur" devices are hopeless.
274 The only thing, that I can say now:
275 It is very sad that we need to keep ugly obsolete
276 code to make them happy.
278 They should be moved to more reasonable state, now
279 they use rebuild_header INSTEAD OF hard_start_xmit!!!
280 Besides that, they are sort of out of date
281 (a lot of redundant clones/copies, useless in 2.1),
282 I wonder why people believe that they work.
288 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
290 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
293 neigh
->ops
= &arp_broken_ops
;
294 neigh
->output
= neigh
->ops
->output
;
299 if (neigh
->type
== RTN_MULTICAST
) {
300 neigh
->nud_state
= NUD_NOARP
;
301 arp_mc_map(addr
, neigh
->ha
, dev
, 1);
302 } else if (dev
->flags
&(IFF_NOARP
|IFF_LOOPBACK
)) {
303 neigh
->nud_state
= NUD_NOARP
;
304 memcpy(neigh
->ha
, dev
->dev_addr
, dev
->addr_len
);
305 } else if (neigh
->type
== RTN_BROADCAST
|| dev
->flags
&IFF_POINTOPOINT
) {
306 neigh
->nud_state
= NUD_NOARP
;
307 memcpy(neigh
->ha
, dev
->broadcast
, dev
->addr_len
);
309 if (dev
->hard_header_cache
)
310 neigh
->ops
= &arp_hh_ops
;
312 neigh
->ops
= &arp_generic_ops
;
313 if (neigh
->nud_state
&NUD_VALID
)
314 neigh
->output
= neigh
->ops
->connected_output
;
316 neigh
->output
= neigh
->ops
->output
;
321 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
)
323 dst_link_failure(skb
);
327 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
)
331 struct net_device
*dev
= neigh
->dev
;
332 u32 target
= *(u32
*)neigh
->primary_key
;
333 int probes
= atomic_read(&neigh
->probes
);
334 struct in_device
*in_dev
= in_dev_get(dev
);
339 switch (IN_DEV_ARP_ANNOUNCE(in_dev
)) {
341 case 0: /* By default announce any local IP */
342 if (skb
&& inet_addr_type(skb
->nh
.iph
->saddr
) == RTN_LOCAL
)
343 saddr
= skb
->nh
.iph
->saddr
;
345 case 1: /* Restrict announcements of saddr in same subnet */
348 saddr
= skb
->nh
.iph
->saddr
;
349 if (inet_addr_type(saddr
) == RTN_LOCAL
) {
350 /* saddr should be known to target */
351 if (inet_addr_onlink(in_dev
, target
, saddr
))
356 case 2: /* Avoid secondary IPs, get a primary/preferred one */
363 saddr
= inet_select_addr(dev
, target
, RT_SCOPE_LINK
);
365 if ((probes
-= neigh
->parms
->ucast_probes
) < 0) {
366 if (!(neigh
->nud_state
&NUD_VALID
))
367 printk(KERN_DEBUG
"trying to ucast probe in NUD_INVALID\n");
369 read_lock_bh(&neigh
->lock
);
370 } else if ((probes
-= neigh
->parms
->app_probes
) < 0) {
377 arp_send(ARPOP_REQUEST
, ETH_P_ARP
, target
, dev
, saddr
,
378 dst_ha
, dev
->dev_addr
, NULL
);
380 read_unlock_bh(&neigh
->lock
);
383 static int arp_ignore(struct in_device
*in_dev
, struct net_device
*dev
,
388 switch (IN_DEV_ARP_IGNORE(in_dev
)) {
389 case 0: /* Reply, the tip is already validated */
391 case 1: /* Reply only if tip is configured on the incoming interface */
393 scope
= RT_SCOPE_HOST
;
396 * Reply only if tip is configured on the incoming interface
397 * and is in same subnet as sip
399 scope
= RT_SCOPE_HOST
;
401 case 3: /* Do not reply for scope host addresses */
403 scope
= RT_SCOPE_LINK
;
406 case 4: /* Reserved */
411 case 8: /* Do not reply */
416 return !inet_confirm_addr(dev
, sip
, tip
, scope
);
419 static int arp_filter(__u32 sip
, __u32 tip
, struct net_device
*dev
)
421 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= sip
,
425 /*unsigned long now; */
427 if (ip_route_output_key(&rt
, &fl
) < 0)
429 if (rt
->u
.dst
.dev
!= dev
) {
430 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER
);
437 /* OBSOLETE FUNCTIONS */
440 * Find an arp mapping in the cache. If not found, post a request.
442 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
443 * even if it exists. It is supposed that skb->dev was mangled
444 * by a virtual device (eql, shaper). Nobody but broken devices
445 * is allowed to use this function, it is scheduled to be removed. --ANK
448 static int arp_set_predefined(int addr_hint
, unsigned char * haddr
, u32 paddr
, struct net_device
* dev
)
452 printk(KERN_DEBUG
"ARP: arp called for own IP address\n");
453 memcpy(haddr
, dev
->dev_addr
, dev
->addr_len
);
456 arp_mc_map(paddr
, haddr
, dev
, 1);
459 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
466 int arp_find(unsigned char *haddr
, struct sk_buff
*skb
)
468 struct net_device
*dev
= skb
->dev
;
473 printk(KERN_DEBUG
"arp_find is called with dst==NULL\n");
478 paddr
= ((struct rtable
*)skb
->dst
)->rt_gateway
;
480 if (arp_set_predefined(inet_addr_type(paddr
), haddr
, paddr
, dev
))
483 n
= __neigh_lookup(&arp_tbl
, &paddr
, dev
, 1);
487 if (n
->nud_state
&NUD_VALID
|| neigh_event_send(n
, skb
) == 0) {
488 read_lock_bh(&n
->lock
);
489 memcpy(haddr
, n
->ha
, dev
->addr_len
);
490 read_unlock_bh(&n
->lock
);
500 /* END OF OBSOLETE FUNCTIONS */
502 int arp_bind_neighbour(struct dst_entry
*dst
)
504 struct net_device
*dev
= dst
->dev
;
505 struct neighbour
*n
= dst
->neighbour
;
510 u32 nexthop
= ((struct rtable
*)dst
)->rt_gateway
;
511 if (dev
->flags
&(IFF_LOOPBACK
|IFF_POINTOPOINT
))
513 n
= __neigh_lookup_errno(
514 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
515 dev
->type
== ARPHRD_ATM
? clip_tbl_hook
:
517 &arp_tbl
, &nexthop
, dev
);
526 * Check if we can use proxy ARP for this path
529 static inline int arp_fwd_proxy(struct in_device
*in_dev
, struct rtable
*rt
)
531 struct in_device
*out_dev
;
534 if (!IN_DEV_PROXY_ARP(in_dev
))
537 if ((imi
= IN_DEV_MEDIUM_ID(in_dev
)) == 0)
542 /* place to check for proxy_arp for routes */
544 if ((out_dev
= in_dev_get(rt
->u
.dst
.dev
)) != NULL
) {
545 omi
= IN_DEV_MEDIUM_ID(out_dev
);
548 return (omi
!= imi
&& omi
!= -1);
552 * Interface to link layer: send routine and receive handler.
556 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
559 struct sk_buff
*arp_create(int type
, int ptype
, u32 dest_ip
,
560 struct net_device
*dev
, u32 src_ip
,
561 unsigned char *dest_hw
, unsigned char *src_hw
,
562 unsigned char *target_hw
)
566 unsigned char *arp_ptr
;
572 skb
= alloc_skb(sizeof(struct arphdr
)+ 2*(dev
->addr_len
+4)
573 + LL_RESERVED_SPACE(dev
), GFP_ATOMIC
);
577 skb_reserve(skb
, LL_RESERVED_SPACE(dev
));
578 skb
->nh
.raw
= skb
->data
;
579 arp
= (struct arphdr
*) skb_put(skb
,sizeof(struct arphdr
) + 2*(dev
->addr_len
+4));
581 skb
->protocol
= htons(ETH_P_ARP
);
583 src_hw
= dev
->dev_addr
;
585 dest_hw
= dev
->broadcast
;
588 * Fill the device header for the ARP frame
590 if (dev
->hard_header
&&
591 dev
->hard_header(skb
,dev
,ptype
,dest_hw
,src_hw
,skb
->len
) < 0)
595 * Fill out the arp protocol part.
597 * The arp hardware type should match the device type, except for FDDI,
598 * which (according to RFC 1390) should always equal 1 (Ethernet).
601 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
602 * DIX code for the protocol. Make these device structure fields.
606 arp
->ar_hrd
= htons(dev
->type
);
607 arp
->ar_pro
= htons(ETH_P_IP
);
610 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
612 arp
->ar_hrd
= htons(ARPHRD_AX25
);
613 arp
->ar_pro
= htons(AX25_P_IP
);
616 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
618 arp
->ar_hrd
= htons(ARPHRD_NETROM
);
619 arp
->ar_pro
= htons(AX25_P_IP
);
626 arp
->ar_hrd
= htons(ARPHRD_ETHER
);
627 arp
->ar_pro
= htons(ETH_P_IP
);
631 case ARPHRD_IEEE802_TR
:
632 arp
->ar_hrd
= htons(ARPHRD_IEEE802
);
633 arp
->ar_pro
= htons(ETH_P_IP
);
638 arp
->ar_hln
= dev
->addr_len
;
640 arp
->ar_op
= htons(type
);
642 arp_ptr
=(unsigned char *)(arp
+1);
644 memcpy(arp_ptr
, src_hw
, dev
->addr_len
);
645 arp_ptr
+=dev
->addr_len
;
646 memcpy(arp_ptr
, &src_ip
,4);
648 if (target_hw
!= NULL
)
649 memcpy(arp_ptr
, target_hw
, dev
->addr_len
);
651 memset(arp_ptr
, 0, dev
->addr_len
);
652 arp_ptr
+=dev
->addr_len
;
653 memcpy(arp_ptr
, &dest_ip
, 4);
663 * Send an arp packet.
665 void arp_xmit(struct sk_buff
*skb
)
667 /* Send it off, maybe filter it using firewalling first. */
668 NF_HOOK(NF_ARP
, NF_ARP_OUT
, skb
, NULL
, skb
->dev
, dev_queue_xmit
);
672 * Create and send an arp packet.
674 void arp_send(int type
, int ptype
, u32 dest_ip
,
675 struct net_device
*dev
, u32 src_ip
,
676 unsigned char *dest_hw
, unsigned char *src_hw
,
677 unsigned char *target_hw
)
682 * No arp on this interface.
685 if (dev
->flags
&IFF_NOARP
)
688 skb
= arp_create(type
, ptype
, dest_ip
, dev
, src_ip
,
689 dest_hw
, src_hw
, target_hw
);
697 static void parp_redo(struct sk_buff
*skb
)
700 arp_rcv(skb
, skb
->dev
, NULL
);
704 * Process an arp request.
707 int arp_process(struct sk_buff
*skb
)
709 struct net_device
*dev
= skb
->dev
;
710 struct in_device
*in_dev
= in_dev_get(dev
);
712 unsigned char *arp_ptr
;
714 unsigned char *sha
, *tha
;
716 u16 dev_type
= dev
->type
;
720 /* arp_rcv below verifies the ARP header and verifies the device
731 if (arp
->ar_pro
!= htons(ETH_P_IP
) ||
732 htons(dev_type
) != arp
->ar_hrd
)
735 #ifdef CONFIG_NET_ETHERNET
739 case ARPHRD_IEEE802_TR
:
747 #if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \
748 defined(CONFIG_FDDI) || defined(CONFIG_NET_FC)
750 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
751 * devices, according to RFC 2625) devices will accept ARP
752 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
753 * This is the case also of FDDI, where the RFC 1390 says that
754 * FDDI devices should accept ARP hardware of (1) Ethernet,
755 * however, to be more robust, we'll accept both 1 (Ethernet)
758 if ((arp
->ar_hrd
!= htons(ARPHRD_ETHER
) &&
759 arp
->ar_hrd
!= htons(ARPHRD_IEEE802
)) ||
760 arp
->ar_pro
!= htons(ETH_P_IP
))
764 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
766 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
767 arp
->ar_hrd
!= htons(ARPHRD_AX25
))
770 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
772 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
773 arp
->ar_hrd
!= htons(ARPHRD_NETROM
))
780 /* Understand only these message types */
782 if (arp
->ar_op
!= htons(ARPOP_REPLY
) &&
783 arp
->ar_op
!= htons(ARPOP_REQUEST
))
789 arp_ptr
= (unsigned char *)(arp
+1);
791 arp_ptr
+= dev
->addr_len
;
792 memcpy(&sip
, arp_ptr
, 4);
795 arp_ptr
+= dev
->addr_len
;
796 memcpy(&tip
, arp_ptr
, 4);
798 * Check for bad requests for 127.x.x.x and requests for multicast
799 * addresses. If this is one such, delete it.
801 if (LOOPBACK(tip
) || MULTICAST(tip
))
805 * Special case: We must set Frame Relay source Q.922 address
807 if (dev_type
== ARPHRD_DLCI
)
808 sha
= dev
->broadcast
;
811 * Process entry. The idea here is we want to send a reply if it is a
812 * request for us or if it is a request for someone else that we hold
813 * a proxy for. We want to add an entry to our cache if it is a reply
814 * to us or if it is a request for our address.
815 * (The assumption for this last is that if someone is requesting our
816 * address, they are probably intending to talk to us, so it saves time
817 * if we cache their address. Their address is also probably not in
818 * our cache, since ours is not in their cache.)
820 * Putting this another way, we only care about replies if they are to
821 * us, in which case we add them to the cache. For requests, we care
822 * about those for us and those for our proxies. We reply to both,
823 * and in the case of requests for us we add the requester to the arp
827 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
829 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
830 inet_addr_type(tip
) == RTN_LOCAL
&&
831 !arp_ignore(in_dev
,dev
,sip
,tip
))
832 arp_send(ARPOP_REPLY
,ETH_P_ARP
,tip
,dev
,tip
,sha
,dev
->dev_addr
,dev
->dev_addr
);
836 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
837 ip_route_input(skb
, tip
, sip
, 0, dev
) == 0) {
839 rt
= (struct rtable
*)skb
->dst
;
840 addr_type
= rt
->rt_type
;
842 if (addr_type
== RTN_LOCAL
) {
843 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
848 dont_send
|= arp_ignore(in_dev
,dev
,sip
,tip
);
849 if (!dont_send
&& IN_DEV_ARPFILTER(in_dev
))
850 dont_send
|= arp_filter(sip
,tip
,dev
);
852 arp_send(ARPOP_REPLY
,ETH_P_ARP
,sip
,dev
,tip
,sha
,dev
->dev_addr
,sha
);
857 } else if (IN_DEV_FORWARD(in_dev
)) {
858 if ((rt
->rt_flags
&RTCF_DNAT
) ||
859 (addr_type
== RTN_UNICAST
&& rt
->u
.dst
.dev
!= dev
&&
860 (arp_fwd_proxy(in_dev
, rt
) || pneigh_lookup(&arp_tbl
, &tip
, dev
, 0)))) {
861 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
865 if (skb
->stamp
.tv_sec
== LOCALLY_ENQUEUED
||
866 skb
->pkt_type
== PACKET_HOST
||
867 in_dev
->arp_parms
->proxy_delay
== 0) {
868 arp_send(ARPOP_REPLY
,ETH_P_ARP
,sip
,dev
,tip
,sha
,dev
->dev_addr
,sha
);
870 pneigh_enqueue(&arp_tbl
, in_dev
->arp_parms
, skb
);
879 /* Update our ARP tables */
881 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 0);
883 #ifdef CONFIG_IP_ACCEPT_UNSOLICITED_ARP
884 /* Unsolicited ARP is not accepted by default.
885 It is possible, that this option should be enabled for some
886 devices (strip is candidate)
889 arp
->ar_op
== htons(ARPOP_REPLY
) &&
890 inet_addr_type(sip
) == RTN_UNICAST
)
891 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, -1);
895 int state
= NUD_REACHABLE
;
898 /* If several different ARP replies follows back-to-back,
899 use the FIRST one. It is possible, if several proxy
900 agents are active. Taking the first reply prevents
901 arp trashing and chooses the fastest router.
903 override
= time_after(jiffies
, n
->updated
+ n
->parms
->locktime
);
905 /* Broadcast replies and request packets
906 do not assert neighbour reachability.
908 if (arp
->ar_op
!= htons(ARPOP_REPLY
) ||
909 skb
->pkt_type
!= PACKET_HOST
)
911 neigh_update(n
, sha
, state
, override
? NEIGH_UPDATE_F_OVERRIDE
: 0);
924 * Receive an arp request from the device layer.
927 int arp_rcv(struct sk_buff
*skb
, struct net_device
*dev
, struct packet_type
*pt
)
931 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
932 if (!pskb_may_pull(skb
, (sizeof(struct arphdr
) +
933 (2 * dev
->addr_len
) +
938 if (arp
->ar_hln
!= dev
->addr_len
||
939 dev
->flags
& IFF_NOARP
||
940 skb
->pkt_type
== PACKET_OTHERHOST
||
941 skb
->pkt_type
== PACKET_LOOPBACK
||
945 if ((skb
= skb_share_check(skb
, GFP_ATOMIC
)) == NULL
)
948 return NF_HOOK(NF_ARP
, NF_ARP_IN
, skb
, dev
, NULL
, arp_process
);
957 * User level interface (ioctl)
961 * Set (create) an ARP cache entry.
964 int arp_req_set(struct arpreq
*r
, struct net_device
* dev
)
966 u32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
967 struct neighbour
*neigh
;
970 if (r
->arp_flags
&ATF_PUBL
) {
971 u32 mask
= ((struct sockaddr_in
*) &r
->arp_netmask
)->sin_addr
.s_addr
;
972 if (mask
&& mask
!= 0xFFFFFFFF)
974 if (!dev
&& (r
->arp_flags
& ATF_COM
)) {
975 dev
= dev_getbyhwaddr(r
->arp_ha
.sa_family
, r
->arp_ha
.sa_data
);
980 if (pneigh_lookup(&arp_tbl
, &ip
, dev
, 1) == NULL
)
985 ipv4_devconf
.proxy_arp
= 1;
988 if (__in_dev_get(dev
)) {
989 __in_dev_get(dev
)->cnf
.proxy_arp
= 1;
995 if (r
->arp_flags
& ATF_PERM
)
996 r
->arp_flags
|= ATF_COM
;
998 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= ip
,
999 .tos
= RTO_ONLINK
} } };
1001 if ((err
= ip_route_output_key(&rt
, &fl
)) != 0)
1003 dev
= rt
->u
.dst
.dev
;
1008 switch (dev
->type
) {
1012 * According to RFC 1390, FDDI devices should accept ARP
1013 * hardware types of 1 (Ethernet). However, to be more
1014 * robust, we'll accept hardware types of either 1 (Ethernet)
1015 * or 6 (IEEE 802.2).
1017 if (r
->arp_ha
.sa_family
!= ARPHRD_FDDI
&&
1018 r
->arp_ha
.sa_family
!= ARPHRD_ETHER
&&
1019 r
->arp_ha
.sa_family
!= ARPHRD_IEEE802
)
1024 if (r
->arp_ha
.sa_family
!= dev
->type
)
1029 neigh
= __neigh_lookup_errno(&arp_tbl
, &ip
, dev
);
1030 err
= PTR_ERR(neigh
);
1031 if (!IS_ERR(neigh
)) {
1032 unsigned state
= NUD_STALE
;
1033 if (r
->arp_flags
& ATF_PERM
)
1034 state
= NUD_PERMANENT
;
1035 err
= neigh_update(neigh
, (r
->arp_flags
&ATF_COM
) ?
1036 r
->arp_ha
.sa_data
: NULL
, state
,
1037 NEIGH_UPDATE_F_OVERRIDE
|
1038 NEIGH_UPDATE_F_ADMIN
);
1039 neigh_release(neigh
);
1044 static unsigned arp_state_to_flags(struct neighbour
*neigh
)
1047 if (neigh
->nud_state
&NUD_PERMANENT
)
1048 flags
= ATF_PERM
|ATF_COM
;
1049 else if (neigh
->nud_state
&NUD_VALID
)
1055 * Get an ARP cache entry.
1058 static int arp_req_get(struct arpreq
*r
, struct net_device
*dev
)
1060 u32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1061 struct neighbour
*neigh
;
1064 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1066 read_lock_bh(&neigh
->lock
);
1067 memcpy(r
->arp_ha
.sa_data
, neigh
->ha
, dev
->addr_len
);
1068 r
->arp_flags
= arp_state_to_flags(neigh
);
1069 read_unlock_bh(&neigh
->lock
);
1070 r
->arp_ha
.sa_family
= dev
->type
;
1071 strlcpy(r
->arp_dev
, dev
->name
, sizeof(r
->arp_dev
));
1072 neigh_release(neigh
);
1078 int arp_req_delete(struct arpreq
*r
, struct net_device
* dev
)
1081 u32 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1082 struct neighbour
*neigh
;
1084 if (r
->arp_flags
& ATF_PUBL
) {
1086 ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1087 if (mask
== 0xFFFFFFFF)
1088 return pneigh_delete(&arp_tbl
, &ip
, dev
);
1091 ipv4_devconf
.proxy_arp
= 0;
1094 if (__in_dev_get(dev
)) {
1095 __in_dev_get(dev
)->cnf
.proxy_arp
= 0;
1104 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= ip
,
1105 .tos
= RTO_ONLINK
} } };
1107 if ((err
= ip_route_output_key(&rt
, &fl
)) != 0)
1109 dev
= rt
->u
.dst
.dev
;
1115 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1117 if (neigh
->nud_state
&~NUD_NOARP
)
1118 err
= neigh_update(neigh
, NULL
, NUD_FAILED
,
1119 NEIGH_UPDATE_F_OVERRIDE
|
1120 NEIGH_UPDATE_F_ADMIN
);
1121 neigh_release(neigh
);
1127 * Handle an ARP layer I/O control request.
1130 int arp_ioctl(unsigned int cmd
, void __user
*arg
)
1134 struct net_device
*dev
= NULL
;
1139 if (!capable(CAP_NET_ADMIN
))
1142 err
= copy_from_user(&r
, arg
, sizeof(struct arpreq
));
1150 if (r
.arp_pa
.sa_family
!= AF_INET
)
1151 return -EPFNOSUPPORT
;
1153 if (!(r
.arp_flags
& ATF_PUBL
) &&
1154 (r
.arp_flags
& (ATF_NETMASK
|ATF_DONTPUB
)))
1156 if (!(r
.arp_flags
& ATF_NETMASK
))
1157 ((struct sockaddr_in
*)&r
.arp_netmask
)->sin_addr
.s_addr
=
1158 htonl(0xFFFFFFFFUL
);
1162 if ((dev
= __dev_get_by_name(r
.arp_dev
)) == NULL
)
1165 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1166 if (!r
.arp_ha
.sa_family
)
1167 r
.arp_ha
.sa_family
= dev
->type
;
1169 if ((r
.arp_flags
& ATF_COM
) && r
.arp_ha
.sa_family
!= dev
->type
)
1171 } else if (cmd
== SIOCGARP
) {
1178 err
= arp_req_delete(&r
, dev
);
1181 err
= arp_req_set(&r
, dev
);
1184 err
= arp_req_get(&r
, dev
);
1185 if (!err
&& copy_to_user(arg
, &r
, sizeof(r
)))
1194 static int arp_netdev_event(struct notifier_block
*this, unsigned long event
, void *ptr
)
1196 struct net_device
*dev
= ptr
;
1199 case NETDEV_CHANGEADDR
:
1200 neigh_changeaddr(&arp_tbl
, dev
);
1210 struct notifier_block arp_netdev_notifier
= {
1211 .notifier_call
= arp_netdev_event
,
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
),
1233 static int arp_proc_init(void);
1235 void __init
arp_init(void)
1237 neigh_table_init(&arp_tbl
);
1239 dev_add_pack(&arp_packet_type
);
1241 #ifdef CONFIG_SYSCTL
1242 neigh_sysctl_register(NULL
, &arp_tbl
.parms
, NET_IPV4
,
1243 NET_IPV4_NEIGH
, "ipv4", NULL
);
1245 register_netdevice_notifier(&arp_netdev_notifier
);
1248 #ifdef CONFIG_PROC_FS
1249 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1251 /* ------------------------------------------------------------------------ */
1253 * ax25 -> ASCII conversion
1255 static char *ax2asc2(ax25_address
*a
, char *buf
)
1260 for (n
= 0, s
= buf
; n
< 6; n
++) {
1261 c
= (a
->ax25_call
[n
] >> 1) & 0x7F;
1263 if (c
!= ' ') *s
++ = c
;
1268 if ((n
= ((a
->ax25_call
[6] >> 1) & 0x0F)) > 9) {
1276 if (*buf
== '\0' || *buf
== '-')
1282 #endif /* CONFIG_AX25 */
1284 #define HBUFFERLEN 30
1286 static void arp_format_neigh_entry(struct seq_file
*seq
,
1287 struct neighbour
*n
)
1289 char hbuffer
[HBUFFERLEN
];
1290 const char hexbuf
[] = "0123456789ABCDEF";
1293 struct net_device
*dev
= n
->dev
;
1294 int hatype
= dev
->type
;
1296 read_lock(&n
->lock
);
1297 /* Convert hardware address to XX:XX:XX:XX ... form. */
1298 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1299 if (hatype
== ARPHRD_AX25
|| hatype
== ARPHRD_NETROM
)
1300 ax2asc2((ax25_address
*)n
->ha
, hbuffer
);
1303 for (k
= 0, j
= 0; k
< HBUFFERLEN
- 3 && j
< dev
->addr_len
; j
++) {
1304 hbuffer
[k
++] = hexbuf
[(n
->ha
[j
] >> 4) & 15];
1305 hbuffer
[k
++] = hexbuf
[n
->ha
[j
] & 15];
1309 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1312 sprintf(tbuf
, "%u.%u.%u.%u", NIPQUAD(*(u32
*)n
->primary_key
));
1313 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1314 tbuf
, hatype
, arp_state_to_flags(n
), hbuffer
, dev
->name
);
1315 read_unlock(&n
->lock
);
1318 static void arp_format_pneigh_entry(struct seq_file
*seq
,
1319 struct pneigh_entry
*n
)
1321 struct net_device
*dev
= n
->dev
;
1322 int hatype
= dev
? dev
->type
: 0;
1325 sprintf(tbuf
, "%u.%u.%u.%u", NIPQUAD(*(u32
*)n
->key
));
1326 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1327 tbuf
, hatype
, ATF_PUBL
| ATF_PERM
, "00:00:00:00:00:00",
1328 dev
? dev
->name
: "*");
1331 static int arp_seq_show(struct seq_file
*seq
, void *v
)
1333 if (v
== SEQ_START_TOKEN
) {
1334 seq_puts(seq
, "IP address HW type Flags "
1335 "HW address Mask Device\n");
1337 struct neigh_seq_state
*state
= seq
->private;
1339 if (state
->flags
& NEIGH_SEQ_IS_PNEIGH
)
1340 arp_format_pneigh_entry(seq
, v
);
1342 arp_format_neigh_entry(seq
, v
);
1348 static void *arp_seq_start(struct seq_file
*seq
, loff_t
*pos
)
1350 /* Don't want to confuse "arp -a" w/ magic entries,
1351 * so we tell the generic iterator to skip NUD_NOARP.
1353 return neigh_seq_start(seq
, pos
, &arp_tbl
, NEIGH_SEQ_SKIP_NOARP
);
1356 /* ------------------------------------------------------------------------ */
1358 static struct seq_operations arp_seq_ops
= {
1359 .start
= arp_seq_start
,
1360 .next
= neigh_seq_next
,
1361 .stop
= neigh_seq_stop
,
1362 .show
= arp_seq_show
,
1365 static int arp_seq_open(struct inode
*inode
, struct file
*file
)
1367 struct seq_file
*seq
;
1369 struct neigh_seq_state
*s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
1374 memset(s
, 0, sizeof(*s
));
1375 rc
= seq_open(file
, &arp_seq_ops
);
1379 seq
= file
->private_data
;
1388 static struct file_operations arp_seq_fops
= {
1389 .owner
= THIS_MODULE
,
1390 .open
= arp_seq_open
,
1392 .llseek
= seq_lseek
,
1393 .release
= seq_release_private
,
1396 static int __init
arp_proc_init(void)
1398 if (!proc_net_fops_create("arp", S_IRUGO
, &arp_seq_fops
))
1403 #else /* CONFIG_PROC_FS */
1405 static int __init
arp_proc_init(void)
1410 #endif /* CONFIG_PROC_FS */
1412 EXPORT_SYMBOL(arp_broken_ops
);
1413 EXPORT_SYMBOL(arp_find
);
1414 EXPORT_SYMBOL(arp_rcv
);
1415 EXPORT_SYMBOL(arp_create
);
1416 EXPORT_SYMBOL(arp_xmit
);
1417 EXPORT_SYMBOL(arp_send
);
1418 EXPORT_SYMBOL(arp_tbl
);
1420 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
1421 EXPORT_SYMBOL(clip_tbl_hook
);