1 /* linux/net/ipv4/arp.c
3 * Copyright (C) 1994 by Florian La Roche
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
16 * Alan Cox : Removed the Ethernet assumptions in
18 * Alan Cox : Fixed some small errors in the ARP
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
40 * Craig Schlenter : Don't modify permanent entry
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
44 * eg intelligent arp probing and
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
51 * Jonathan Layes : Added arpd support through kerneld
52 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
76 #include <linux/module.h>
77 #include <linux/types.h>
78 #include <linux/string.h>
79 #include <linux/kernel.h>
80 #include <linux/capability.h>
81 #include <linux/socket.h>
82 #include <linux/sockios.h>
83 #include <linux/errno.h>
86 #include <linux/inet.h>
87 #include <linux/inetdevice.h>
88 #include <linux/netdevice.h>
89 #include <linux/etherdevice.h>
90 #include <linux/fddidevice.h>
91 #include <linux/if_arp.h>
92 #include <linux/trdevice.h>
93 #include <linux/skbuff.h>
94 #include <linux/proc_fs.h>
95 #include <linux/seq_file.h>
96 #include <linux/stat.h>
97 #include <linux/init.h>
98 #include <linux/net.h>
99 #include <linux/rcupdate.h>
100 #include <linux/slab.h>
102 #include <linux/sysctl.h>
105 #include <net/net_namespace.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
;
118 EXPORT_SYMBOL(clip_tbl_hook
);
121 #include <asm/system.h>
122 #include <linux/uaccess.h>
124 #include <linux/netfilter_arp.h>
127 * Interface to generic neighbour cache.
129 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
, __u32 rnd
);
130 static int arp_constructor(struct neighbour
*neigh
);
131 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
);
132 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
);
133 static void parp_redo(struct sk_buff
*skb
);
135 static const struct neigh_ops arp_generic_ops
= {
137 .solicit
= arp_solicit
,
138 .error_report
= arp_error_report
,
139 .output
= neigh_resolve_output
,
140 .connected_output
= neigh_connected_output
,
143 static const struct neigh_ops arp_hh_ops
= {
145 .solicit
= arp_solicit
,
146 .error_report
= arp_error_report
,
147 .output
= neigh_resolve_output
,
148 .connected_output
= neigh_resolve_output
,
151 static const struct neigh_ops arp_direct_ops
= {
153 .output
= neigh_direct_output
,
154 .connected_output
= neigh_direct_output
,
157 static const struct neigh_ops arp_broken_ops
= {
159 .solicit
= arp_solicit
,
160 .error_report
= arp_error_report
,
161 .output
= neigh_compat_output
,
162 .connected_output
= neigh_compat_output
,
165 struct neigh_table arp_tbl
= {
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
,
179 .queue_len_bytes
= 64*1024,
182 .anycast_delay
= 1 * HZ
,
183 .proxy_delay
= (8 * HZ
) / 10,
187 .gc_interval
= 30 * HZ
,
192 EXPORT_SYMBOL(arp_tbl
);
194 int arp_mc_map(__be32 addr
, u8
*haddr
, struct net_device
*dev
, int dir
)
200 ip_eth_mc_map(addr
, haddr
);
202 case ARPHRD_IEEE802_TR
:
203 ip_tr_mc_map(addr
, haddr
);
205 case ARPHRD_INFINIBAND
:
206 ip_ib_mc_map(addr
, dev
->broadcast
, haddr
);
209 ip_ipgre_mc_map(addr
, dev
->broadcast
, haddr
);
213 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
221 static u32
arp_hash(const void *pkey
,
222 const struct net_device
*dev
,
225 return arp_hashfn(*(u32
*)pkey
, dev
, hash_rnd
);
228 static int arp_constructor(struct neighbour
*neigh
)
230 __be32 addr
= *(__be32
*)neigh
->primary_key
;
231 struct net_device
*dev
= neigh
->dev
;
232 struct in_device
*in_dev
;
233 struct neigh_parms
*parms
;
236 in_dev
= __in_dev_get_rcu(dev
);
237 if (in_dev
== NULL
) {
242 neigh
->type
= inet_addr_type(dev_net(dev
), addr
);
244 parms
= in_dev
->arp_parms
;
245 __neigh_parms_put(neigh
->parms
);
246 neigh
->parms
= neigh_parms_clone(parms
);
249 if (!dev
->header_ops
) {
250 neigh
->nud_state
= NUD_NOARP
;
251 neigh
->ops
= &arp_direct_ops
;
252 neigh
->output
= neigh_direct_output
;
254 /* Good devices (checked by reading texts, but only Ethernet is
257 ARPHRD_ETHER: (ethernet, apfddi)
260 ARPHRD_METRICOM: (strip)
264 ARPHRD_IPDDP will also work, if author repairs it.
265 I did not it, because this driver does not work even
270 /* So... these "amateur" devices are hopeless.
271 The only thing, that I can say now:
272 It is very sad that we need to keep ugly obsolete
273 code to make them happy.
275 They should be moved to more reasonable state, now
276 they use rebuild_header INSTEAD OF hard_start_xmit!!!
277 Besides that, they are sort of out of date
278 (a lot of redundant clones/copies, useless in 2.1),
279 I wonder why people believe that they work.
285 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
287 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
290 neigh
->ops
= &arp_broken_ops
;
291 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
||
305 (dev
->flags
& IFF_POINTOPOINT
)) {
306 neigh
->nud_state
= NUD_NOARP
;
307 memcpy(neigh
->ha
, dev
->broadcast
, dev
->addr_len
);
310 if (dev
->header_ops
->cache
)
311 neigh
->ops
= &arp_hh_ops
;
313 neigh
->ops
= &arp_generic_ops
;
315 if (neigh
->nud_state
& NUD_VALID
)
316 neigh
->output
= neigh
->ops
->connected_output
;
318 neigh
->output
= neigh
->ops
->output
;
323 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
)
325 dst_link_failure(skb
);
329 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
)
333 struct net_device
*dev
= neigh
->dev
;
334 __be32 target
= *(__be32
*)neigh
->primary_key
;
335 int probes
= atomic_read(&neigh
->probes
);
336 struct in_device
*in_dev
;
339 in_dev
= __in_dev_get_rcu(dev
);
344 switch (IN_DEV_ARP_ANNOUNCE(in_dev
)) {
346 case 0: /* By default announce any local IP */
347 if (skb
&& inet_addr_type(dev_net(dev
),
348 ip_hdr(skb
)->saddr
) == RTN_LOCAL
)
349 saddr
= ip_hdr(skb
)->saddr
;
351 case 1: /* Restrict announcements of saddr in same subnet */
354 saddr
= ip_hdr(skb
)->saddr
;
355 if (inet_addr_type(dev_net(dev
), saddr
) == RTN_LOCAL
) {
356 /* saddr should be known to target */
357 if (inet_addr_onlink(in_dev
, target
, saddr
))
362 case 2: /* Avoid secondary IPs, get a primary/preferred one */
368 saddr
= inet_select_addr(dev
, target
, RT_SCOPE_LINK
);
370 probes
-= neigh
->parms
->ucast_probes
;
372 if (!(neigh
->nud_state
& NUD_VALID
))
374 "trying to ucast probe in NUD_INVALID\n");
376 read_lock_bh(&neigh
->lock
);
378 probes
-= neigh
->parms
->app_probes
;
387 arp_send(ARPOP_REQUEST
, ETH_P_ARP
, target
, dev
, saddr
,
388 dst_ha
, dev
->dev_addr
, NULL
);
390 read_unlock_bh(&neigh
->lock
);
393 static int arp_ignore(struct in_device
*in_dev
, __be32 sip
, __be32 tip
)
397 switch (IN_DEV_ARP_IGNORE(in_dev
)) {
398 case 0: /* Reply, the tip is already validated */
400 case 1: /* Reply only if tip is configured on the incoming interface */
402 scope
= RT_SCOPE_HOST
;
405 * Reply only if tip is configured on the incoming interface
406 * and is in same subnet as sip
408 scope
= RT_SCOPE_HOST
;
410 case 3: /* Do not reply for scope host addresses */
412 scope
= RT_SCOPE_LINK
;
414 case 4: /* Reserved */
419 case 8: /* Do not reply */
424 return !inet_confirm_addr(in_dev
, sip
, tip
, scope
);
427 static int arp_filter(__be32 sip
, __be32 tip
, struct net_device
*dev
)
431 /*unsigned long now; */
432 struct net
*net
= dev_net(dev
);
434 rt
= ip_route_output(net
, sip
, tip
, 0, 0);
437 if (rt
->dst
.dev
!= dev
) {
438 NET_INC_STATS_BH(net
, LINUX_MIB_ARPFILTER
);
445 /* OBSOLETE FUNCTIONS */
448 * Find an arp mapping in the cache. If not found, post a request.
450 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
451 * even if it exists. It is supposed that skb->dev was mangled
452 * by a virtual device (eql, shaper). Nobody but broken devices
453 * is allowed to use this function, it is scheduled to be removed. --ANK
456 static int arp_set_predefined(int addr_hint
, unsigned char *haddr
,
457 __be32 paddr
, struct net_device
*dev
)
461 printk(KERN_DEBUG
"ARP: arp called for own IP address\n");
462 memcpy(haddr
, dev
->dev_addr
, dev
->addr_len
);
465 arp_mc_map(paddr
, haddr
, dev
, 1);
468 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
475 int arp_find(unsigned char *haddr
, struct sk_buff
*skb
)
477 struct net_device
*dev
= skb
->dev
;
482 printk(KERN_DEBUG
"arp_find is called with dst==NULL\n");
487 paddr
= skb_rtable(skb
)->rt_gateway
;
489 if (arp_set_predefined(inet_addr_type(dev_net(dev
), paddr
), haddr
,
493 n
= __neigh_lookup(&arp_tbl
, &paddr
, dev
, 1);
497 if (n
->nud_state
& NUD_VALID
|| neigh_event_send(n
, skb
) == 0) {
498 neigh_ha_snapshot(haddr
, n
, dev
);
507 EXPORT_SYMBOL(arp_find
);
509 /* END OF OBSOLETE FUNCTIONS */
512 * Check if we can use proxy ARP for this path
514 static inline int arp_fwd_proxy(struct in_device
*in_dev
,
515 struct net_device
*dev
, struct rtable
*rt
)
517 struct in_device
*out_dev
;
520 if (rt
->dst
.dev
== dev
)
523 if (!IN_DEV_PROXY_ARP(in_dev
))
525 imi
= IN_DEV_MEDIUM_ID(in_dev
);
531 /* place to check for proxy_arp for routes */
533 out_dev
= __in_dev_get_rcu(rt
->dst
.dev
);
535 omi
= IN_DEV_MEDIUM_ID(out_dev
);
537 return omi
!= imi
&& omi
!= -1;
541 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
543 * RFC3069 supports proxy arp replies back to the same interface. This
544 * is done to support (ethernet) switch features, like RFC 3069, where
545 * the individual ports are not allowed to communicate with each
546 * other, BUT they are allowed to talk to the upstream router. As
547 * described in RFC 3069, it is possible to allow these hosts to
548 * communicate through the upstream router, by proxy_arp'ing.
550 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
552 * This technology is known by different names:
553 * In RFC 3069 it is called VLAN Aggregation.
554 * Cisco and Allied Telesyn call it Private VLAN.
555 * Hewlett-Packard call it Source-Port filtering or port-isolation.
556 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
559 static inline int arp_fwd_pvlan(struct in_device
*in_dev
,
560 struct net_device
*dev
, struct rtable
*rt
,
561 __be32 sip
, __be32 tip
)
563 /* Private VLAN is only concerned about the same ethernet segment */
564 if (rt
->dst
.dev
!= dev
)
567 /* Don't reply on self probes (often done by windowz boxes)*/
571 if (IN_DEV_PROXY_ARP_PVLAN(in_dev
))
578 * Interface to link layer: send routine and receive handler.
582 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
585 struct sk_buff
*arp_create(int type
, int ptype
, __be32 dest_ip
,
586 struct net_device
*dev
, __be32 src_ip
,
587 const unsigned char *dest_hw
,
588 const unsigned char *src_hw
,
589 const unsigned char *target_hw
)
593 unsigned char *arp_ptr
;
594 int hlen
= LL_RESERVED_SPACE(dev
);
595 int tlen
= dev
->needed_tailroom
;
601 skb
= alloc_skb(arp_hdr_len(dev
) + hlen
+ tlen
, GFP_ATOMIC
);
605 skb_reserve(skb
, hlen
);
606 skb_reset_network_header(skb
);
607 arp
= (struct arphdr
*) skb_put(skb
, arp_hdr_len(dev
));
609 skb
->protocol
= htons(ETH_P_ARP
);
611 src_hw
= dev
->dev_addr
;
613 dest_hw
= dev
->broadcast
;
616 * Fill the device header for the ARP frame
618 if (dev_hard_header(skb
, dev
, ptype
, dest_hw
, src_hw
, skb
->len
) < 0)
622 * Fill out the arp protocol part.
624 * The arp hardware type should match the device type, except for FDDI,
625 * which (according to RFC 1390) should always equal 1 (Ethernet).
628 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
629 * DIX code for the protocol. Make these device structure fields.
633 arp
->ar_hrd
= htons(dev
->type
);
634 arp
->ar_pro
= htons(ETH_P_IP
);
637 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
639 arp
->ar_hrd
= htons(ARPHRD_AX25
);
640 arp
->ar_pro
= htons(AX25_P_IP
);
643 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
645 arp
->ar_hrd
= htons(ARPHRD_NETROM
);
646 arp
->ar_pro
= htons(AX25_P_IP
);
651 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
653 arp
->ar_hrd
= htons(ARPHRD_ETHER
);
654 arp
->ar_pro
= htons(ETH_P_IP
);
657 #if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
658 case ARPHRD_IEEE802_TR
:
659 arp
->ar_hrd
= htons(ARPHRD_IEEE802
);
660 arp
->ar_pro
= htons(ETH_P_IP
);
665 arp
->ar_hln
= dev
->addr_len
;
667 arp
->ar_op
= htons(type
);
669 arp_ptr
= (unsigned char *)(arp
+ 1);
671 memcpy(arp_ptr
, src_hw
, dev
->addr_len
);
672 arp_ptr
+= dev
->addr_len
;
673 memcpy(arp_ptr
, &src_ip
, 4);
675 if (target_hw
!= NULL
)
676 memcpy(arp_ptr
, target_hw
, dev
->addr_len
);
678 memset(arp_ptr
, 0, dev
->addr_len
);
679 arp_ptr
+= dev
->addr_len
;
680 memcpy(arp_ptr
, &dest_ip
, 4);
688 EXPORT_SYMBOL(arp_create
);
691 * Send an arp packet.
693 void arp_xmit(struct sk_buff
*skb
)
695 /* Send it off, maybe filter it using firewalling first. */
696 NF_HOOK(NFPROTO_ARP
, NF_ARP_OUT
, skb
, NULL
, skb
->dev
, dev_queue_xmit
);
698 EXPORT_SYMBOL(arp_xmit
);
701 * Create and send an arp packet.
703 void arp_send(int type
, int ptype
, __be32 dest_ip
,
704 struct net_device
*dev
, __be32 src_ip
,
705 const unsigned char *dest_hw
, const unsigned char *src_hw
,
706 const unsigned char *target_hw
)
711 * No arp on this interface.
714 if (dev
->flags
&IFF_NOARP
)
717 skb
= arp_create(type
, ptype
, dest_ip
, dev
, src_ip
,
718 dest_hw
, src_hw
, target_hw
);
724 EXPORT_SYMBOL(arp_send
);
727 * Process an arp request.
730 static int arp_process(struct sk_buff
*skb
)
732 struct net_device
*dev
= skb
->dev
;
733 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
735 unsigned char *arp_ptr
;
739 u16 dev_type
= dev
->type
;
742 struct net
*net
= dev_net(dev
);
744 /* arp_rcv below verifies the ARP header and verifies the device
755 if (arp
->ar_pro
!= htons(ETH_P_IP
) ||
756 htons(dev_type
) != arp
->ar_hrd
)
760 case ARPHRD_IEEE802_TR
:
764 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
765 * devices, according to RFC 2625) devices will accept ARP
766 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
767 * This is the case also of FDDI, where the RFC 1390 says that
768 * FDDI devices should accept ARP hardware of (1) Ethernet,
769 * however, to be more robust, we'll accept both 1 (Ethernet)
772 if ((arp
->ar_hrd
!= htons(ARPHRD_ETHER
) &&
773 arp
->ar_hrd
!= htons(ARPHRD_IEEE802
)) ||
774 arp
->ar_pro
!= htons(ETH_P_IP
))
778 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
779 arp
->ar_hrd
!= htons(ARPHRD_AX25
))
783 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
784 arp
->ar_hrd
!= htons(ARPHRD_NETROM
))
789 /* Understand only these message types */
791 if (arp
->ar_op
!= htons(ARPOP_REPLY
) &&
792 arp
->ar_op
!= htons(ARPOP_REQUEST
))
798 arp_ptr
= (unsigned char *)(arp
+ 1);
800 arp_ptr
+= dev
->addr_len
;
801 memcpy(&sip
, arp_ptr
, 4);
803 arp_ptr
+= dev
->addr_len
;
804 memcpy(&tip
, arp_ptr
, 4);
806 * Check for bad requests for 127.x.x.x and requests for multicast
807 * addresses. If this is one such, delete it.
809 if (ipv4_is_loopback(tip
) || ipv4_is_multicast(tip
))
813 * Special case: We must set Frame Relay source Q.922 address
815 if (dev_type
== ARPHRD_DLCI
)
816 sha
= dev
->broadcast
;
819 * Process entry. The idea here is we want to send a reply if it is a
820 * request for us or if it is a request for someone else that we hold
821 * a proxy for. We want to add an entry to our cache if it is a reply
822 * to us or if it is a request for our address.
823 * (The assumption for this last is that if someone is requesting our
824 * address, they are probably intending to talk to us, so it saves time
825 * if we cache their address. Their address is also probably not in
826 * our cache, since ours is not in their cache.)
828 * Putting this another way, we only care about replies if they are to
829 * us, in which case we add them to the cache. For requests, we care
830 * about those for us and those for our proxies. We reply to both,
831 * and in the case of requests for us we add the requester to the arp
835 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
837 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
838 inet_addr_type(net
, tip
) == RTN_LOCAL
&&
839 !arp_ignore(in_dev
, sip
, tip
))
840 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
, dev
, tip
, sha
,
845 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
846 ip_route_input_noref(skb
, tip
, sip
, 0, dev
) == 0) {
848 rt
= skb_rtable(skb
);
849 addr_type
= rt
->rt_type
;
851 if (addr_type
== RTN_LOCAL
) {
854 dont_send
= arp_ignore(in_dev
, sip
, tip
);
855 if (!dont_send
&& IN_DEV_ARPFILTER(in_dev
))
856 dont_send
= arp_filter(sip
, tip
, dev
);
858 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
860 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
,
861 dev
, tip
, sha
, dev
->dev_addr
,
867 } else if (IN_DEV_FORWARD(in_dev
)) {
868 if (addr_type
== RTN_UNICAST
&&
869 (arp_fwd_proxy(in_dev
, dev
, rt
) ||
870 arp_fwd_pvlan(in_dev
, dev
, rt
, sip
, tip
) ||
871 pneigh_lookup(&arp_tbl
, net
, &tip
, dev
, 0))) {
872 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
876 if (NEIGH_CB(skb
)->flags
& LOCALLY_ENQUEUED
||
877 skb
->pkt_type
== PACKET_HOST
||
878 in_dev
->arp_parms
->proxy_delay
== 0) {
879 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
,
880 dev
, tip
, sha
, dev
->dev_addr
,
883 pneigh_enqueue(&arp_tbl
,
884 in_dev
->arp_parms
, skb
);
892 /* Update our ARP tables */
894 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 0);
896 if (IPV4_DEVCONF_ALL(dev_net(dev
), ARP_ACCEPT
)) {
897 /* Unsolicited ARP is not accepted by default.
898 It is possible, that this option should be enabled for some
899 devices (strip is candidate)
902 (arp
->ar_op
== htons(ARPOP_REPLY
) ||
903 (arp
->ar_op
== htons(ARPOP_REQUEST
) && tip
== sip
)) &&
904 inet_addr_type(net
, sip
) == RTN_UNICAST
)
905 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 1);
909 int state
= NUD_REACHABLE
;
912 /* If several different ARP replies follows back-to-back,
913 use the FIRST one. It is possible, if several proxy
914 agents are active. Taking the first reply prevents
915 arp trashing and chooses the fastest router.
917 override
= time_after(jiffies
, n
->updated
+ n
->parms
->locktime
);
919 /* Broadcast replies and request packets
920 do not assert neighbour reachability.
922 if (arp
->ar_op
!= htons(ARPOP_REPLY
) ||
923 skb
->pkt_type
!= PACKET_HOST
)
925 neigh_update(n
, sha
, state
,
926 override
? NEIGH_UPDATE_F_OVERRIDE
: 0);
935 static void parp_redo(struct sk_buff
*skb
)
942 * Receive an arp request from the device layer.
945 static int arp_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
946 struct packet_type
*pt
, struct net_device
*orig_dev
)
950 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
951 if (!pskb_may_pull(skb
, arp_hdr_len(dev
)))
955 if (arp
->ar_hln
!= dev
->addr_len
||
956 dev
->flags
& IFF_NOARP
||
957 skb
->pkt_type
== PACKET_OTHERHOST
||
958 skb
->pkt_type
== PACKET_LOOPBACK
||
962 skb
= skb_share_check(skb
, GFP_ATOMIC
);
966 memset(NEIGH_CB(skb
), 0, sizeof(struct neighbour_cb
));
968 return NF_HOOK(NFPROTO_ARP
, NF_ARP_IN
, skb
, dev
, NULL
, arp_process
);
977 * User level interface (ioctl)
981 * Set (create) an ARP cache entry.
984 static int arp_req_set_proxy(struct net
*net
, struct net_device
*dev
, int on
)
987 IPV4_DEVCONF_ALL(net
, PROXY_ARP
) = on
;
990 if (__in_dev_get_rtnl(dev
)) {
991 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev
), PROXY_ARP
, on
);
997 static int arp_req_set_public(struct net
*net
, struct arpreq
*r
,
998 struct net_device
*dev
)
1000 __be32 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1001 __be32 mask
= ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1003 if (mask
&& mask
!= htonl(0xFFFFFFFF))
1005 if (!dev
&& (r
->arp_flags
& ATF_COM
)) {
1006 dev
= dev_getbyhwaddr_rcu(net
, r
->arp_ha
.sa_family
,
1012 if (pneigh_lookup(&arp_tbl
, net
, &ip
, dev
, 1) == NULL
)
1017 return arp_req_set_proxy(net
, dev
, 1);
1020 static int arp_req_set(struct net
*net
, struct arpreq
*r
,
1021 struct net_device
*dev
)
1024 struct neighbour
*neigh
;
1027 if (r
->arp_flags
& ATF_PUBL
)
1028 return arp_req_set_public(net
, r
, dev
);
1030 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1031 if (r
->arp_flags
& ATF_PERM
)
1032 r
->arp_flags
|= ATF_COM
;
1034 struct rtable
*rt
= ip_route_output(net
, ip
, 0, RTO_ONLINK
, 0);
1043 switch (dev
->type
) {
1044 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
1047 * According to RFC 1390, FDDI devices should accept ARP
1048 * hardware types of 1 (Ethernet). However, to be more
1049 * robust, we'll accept hardware types of either 1 (Ethernet)
1050 * or 6 (IEEE 802.2).
1052 if (r
->arp_ha
.sa_family
!= ARPHRD_FDDI
&&
1053 r
->arp_ha
.sa_family
!= ARPHRD_ETHER
&&
1054 r
->arp_ha
.sa_family
!= ARPHRD_IEEE802
)
1059 if (r
->arp_ha
.sa_family
!= dev
->type
)
1064 neigh
= __neigh_lookup_errno(&arp_tbl
, &ip
, dev
);
1065 err
= PTR_ERR(neigh
);
1066 if (!IS_ERR(neigh
)) {
1067 unsigned state
= NUD_STALE
;
1068 if (r
->arp_flags
& ATF_PERM
)
1069 state
= NUD_PERMANENT
;
1070 err
= neigh_update(neigh
, (r
->arp_flags
& ATF_COM
) ?
1071 r
->arp_ha
.sa_data
: NULL
, state
,
1072 NEIGH_UPDATE_F_OVERRIDE
|
1073 NEIGH_UPDATE_F_ADMIN
);
1074 neigh_release(neigh
);
1079 static unsigned arp_state_to_flags(struct neighbour
*neigh
)
1081 if (neigh
->nud_state
&NUD_PERMANENT
)
1082 return ATF_PERM
| ATF_COM
;
1083 else if (neigh
->nud_state
&NUD_VALID
)
1090 * Get an ARP cache entry.
1093 static int arp_req_get(struct arpreq
*r
, struct net_device
*dev
)
1095 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1096 struct neighbour
*neigh
;
1099 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1101 read_lock_bh(&neigh
->lock
);
1102 memcpy(r
->arp_ha
.sa_data
, neigh
->ha
, dev
->addr_len
);
1103 r
->arp_flags
= arp_state_to_flags(neigh
);
1104 read_unlock_bh(&neigh
->lock
);
1105 r
->arp_ha
.sa_family
= dev
->type
;
1106 strlcpy(r
->arp_dev
, dev
->name
, sizeof(r
->arp_dev
));
1107 neigh_release(neigh
);
1113 int arp_invalidate(struct net_device
*dev
, __be32 ip
)
1115 struct neighbour
*neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1119 if (neigh
->nud_state
& ~NUD_NOARP
)
1120 err
= neigh_update(neigh
, NULL
, NUD_FAILED
,
1121 NEIGH_UPDATE_F_OVERRIDE
|
1122 NEIGH_UPDATE_F_ADMIN
);
1123 neigh_release(neigh
);
1128 EXPORT_SYMBOL(arp_invalidate
);
1130 static int arp_req_delete_public(struct net
*net
, struct arpreq
*r
,
1131 struct net_device
*dev
)
1133 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1134 __be32 mask
= ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1136 if (mask
== htonl(0xFFFFFFFF))
1137 return pneigh_delete(&arp_tbl
, net
, &ip
, dev
);
1142 return arp_req_set_proxy(net
, dev
, 0);
1145 static int arp_req_delete(struct net
*net
, struct arpreq
*r
,
1146 struct net_device
*dev
)
1150 if (r
->arp_flags
& ATF_PUBL
)
1151 return arp_req_delete_public(net
, r
, dev
);
1153 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1155 struct rtable
*rt
= ip_route_output(net
, ip
, 0, RTO_ONLINK
, 0);
1163 return arp_invalidate(dev
, ip
);
1167 * Handle an ARP layer I/O control request.
1170 int arp_ioctl(struct net
*net
, unsigned int cmd
, void __user
*arg
)
1174 struct net_device
*dev
= NULL
;
1179 if (!capable(CAP_NET_ADMIN
))
1182 err
= copy_from_user(&r
, arg
, sizeof(struct arpreq
));
1190 if (r
.arp_pa
.sa_family
!= AF_INET
)
1191 return -EPFNOSUPPORT
;
1193 if (!(r
.arp_flags
& ATF_PUBL
) &&
1194 (r
.arp_flags
& (ATF_NETMASK
| ATF_DONTPUB
)))
1196 if (!(r
.arp_flags
& ATF_NETMASK
))
1197 ((struct sockaddr_in
*)&r
.arp_netmask
)->sin_addr
.s_addr
=
1198 htonl(0xFFFFFFFFUL
);
1202 dev
= __dev_get_by_name(net
, r
.arp_dev
);
1206 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1207 if (!r
.arp_ha
.sa_family
)
1208 r
.arp_ha
.sa_family
= dev
->type
;
1210 if ((r
.arp_flags
& ATF_COM
) && r
.arp_ha
.sa_family
!= dev
->type
)
1212 } else if (cmd
== SIOCGARP
) {
1219 err
= arp_req_delete(net
, &r
, dev
);
1222 err
= arp_req_set(net
, &r
, dev
);
1225 err
= arp_req_get(&r
, dev
);
1230 if (cmd
== SIOCGARP
&& !err
&& copy_to_user(arg
, &r
, sizeof(r
)))
1235 static int arp_netdev_event(struct notifier_block
*this, unsigned long event
,
1238 struct net_device
*dev
= ptr
;
1241 case NETDEV_CHANGEADDR
:
1242 neigh_changeaddr(&arp_tbl
, dev
);
1243 rt_cache_flush(dev_net(dev
), 0);
1252 static struct notifier_block arp_netdev_notifier
= {
1253 .notifier_call
= arp_netdev_event
,
1256 /* Note, that it is not on notifier chain.
1257 It is necessary, that this routine was called after route cache will be
1260 void arp_ifdown(struct net_device
*dev
)
1262 neigh_ifdown(&arp_tbl
, dev
);
1267 * Called once on startup.
1270 static struct packet_type arp_packet_type __read_mostly
= {
1271 .type
= cpu_to_be16(ETH_P_ARP
),
1275 static int arp_proc_init(void);
1277 void __init
arp_init(void)
1279 neigh_table_init(&arp_tbl
);
1281 dev_add_pack(&arp_packet_type
);
1283 #ifdef CONFIG_SYSCTL
1284 neigh_sysctl_register(NULL
, &arp_tbl
.parms
, "ipv4", NULL
);
1286 register_netdevice_notifier(&arp_netdev_notifier
);
1289 #ifdef CONFIG_PROC_FS
1290 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1292 /* ------------------------------------------------------------------------ */
1294 * ax25 -> ASCII conversion
1296 static char *ax2asc2(ax25_address
*a
, char *buf
)
1301 for (n
= 0, s
= buf
; n
< 6; n
++) {
1302 c
= (a
->ax25_call
[n
] >> 1) & 0x7F;
1309 n
= (a
->ax25_call
[6] >> 1) & 0x0F;
1318 if (*buf
== '\0' || *buf
== '-')
1323 #endif /* CONFIG_AX25 */
1325 #define HBUFFERLEN 30
1327 static void arp_format_neigh_entry(struct seq_file
*seq
,
1328 struct neighbour
*n
)
1330 char hbuffer
[HBUFFERLEN
];
1333 struct net_device
*dev
= n
->dev
;
1334 int hatype
= dev
->type
;
1336 read_lock(&n
->lock
);
1337 /* Convert hardware address to XX:XX:XX:XX ... form. */
1338 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1339 if (hatype
== ARPHRD_AX25
|| hatype
== ARPHRD_NETROM
)
1340 ax2asc2((ax25_address
*)n
->ha
, hbuffer
);
1343 for (k
= 0, j
= 0; k
< HBUFFERLEN
- 3 && j
< dev
->addr_len
; j
++) {
1344 hbuffer
[k
++] = hex_asc_hi(n
->ha
[j
]);
1345 hbuffer
[k
++] = hex_asc_lo(n
->ha
[j
]);
1351 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1354 sprintf(tbuf
, "%pI4", n
->primary_key
);
1355 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1356 tbuf
, hatype
, arp_state_to_flags(n
), hbuffer
, dev
->name
);
1357 read_unlock(&n
->lock
);
1360 static void arp_format_pneigh_entry(struct seq_file
*seq
,
1361 struct pneigh_entry
*n
)
1363 struct net_device
*dev
= n
->dev
;
1364 int hatype
= dev
? dev
->type
: 0;
1367 sprintf(tbuf
, "%pI4", n
->key
);
1368 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1369 tbuf
, hatype
, ATF_PUBL
| ATF_PERM
, "00:00:00:00:00:00",
1370 dev
? dev
->name
: "*");
1373 static int arp_seq_show(struct seq_file
*seq
, void *v
)
1375 if (v
== SEQ_START_TOKEN
) {
1376 seq_puts(seq
, "IP address HW type Flags "
1377 "HW address Mask Device\n");
1379 struct neigh_seq_state
*state
= seq
->private;
1381 if (state
->flags
& NEIGH_SEQ_IS_PNEIGH
)
1382 arp_format_pneigh_entry(seq
, v
);
1384 arp_format_neigh_entry(seq
, v
);
1390 static void *arp_seq_start(struct seq_file
*seq
, loff_t
*pos
)
1392 /* Don't want to confuse "arp -a" w/ magic entries,
1393 * so we tell the generic iterator to skip NUD_NOARP.
1395 return neigh_seq_start(seq
, pos
, &arp_tbl
, NEIGH_SEQ_SKIP_NOARP
);
1398 /* ------------------------------------------------------------------------ */
1400 static const struct seq_operations arp_seq_ops
= {
1401 .start
= arp_seq_start
,
1402 .next
= neigh_seq_next
,
1403 .stop
= neigh_seq_stop
,
1404 .show
= arp_seq_show
,
1407 static int arp_seq_open(struct inode
*inode
, struct file
*file
)
1409 return seq_open_net(inode
, file
, &arp_seq_ops
,
1410 sizeof(struct neigh_seq_state
));
1413 static const struct file_operations arp_seq_fops
= {
1414 .owner
= THIS_MODULE
,
1415 .open
= arp_seq_open
,
1417 .llseek
= seq_lseek
,
1418 .release
= seq_release_net
,
1422 static int __net_init
arp_net_init(struct net
*net
)
1424 if (!proc_net_fops_create(net
, "arp", S_IRUGO
, &arp_seq_fops
))
1429 static void __net_exit
arp_net_exit(struct net
*net
)
1431 proc_net_remove(net
, "arp");
1434 static struct pernet_operations arp_net_ops
= {
1435 .init
= arp_net_init
,
1436 .exit
= arp_net_exit
,
1439 static int __init
arp_proc_init(void)
1441 return register_pernet_subsys(&arp_net_ops
);
1444 #else /* CONFIG_PROC_FS */
1446 static int __init
arp_proc_init(void)
1451 #endif /* CONFIG_PROC_FS */