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
,
141 .hh_output
= dev_queue_xmit
,
142 .queue_xmit
= dev_queue_xmit
,
145 static const struct neigh_ops arp_hh_ops
= {
147 .solicit
= arp_solicit
,
148 .error_report
= arp_error_report
,
149 .output
= neigh_resolve_output
,
150 .connected_output
= neigh_resolve_output
,
151 .hh_output
= dev_queue_xmit
,
152 .queue_xmit
= dev_queue_xmit
,
155 static const struct neigh_ops arp_direct_ops
= {
157 .output
= dev_queue_xmit
,
158 .connected_output
= dev_queue_xmit
,
159 .hh_output
= dev_queue_xmit
,
160 .queue_xmit
= dev_queue_xmit
,
163 static const struct neigh_ops arp_broken_ops
= {
165 .solicit
= arp_solicit
,
166 .error_report
= arp_error_report
,
167 .output
= neigh_compat_output
,
168 .connected_output
= neigh_compat_output
,
169 .hh_output
= dev_queue_xmit
,
170 .queue_xmit
= dev_queue_xmit
,
173 struct neigh_table arp_tbl
= {
175 .entry_size
= sizeof(struct neighbour
) + 4,
178 .constructor
= arp_constructor
,
179 .proxy_redo
= parp_redo
,
183 .base_reachable_time
= 30 * HZ
,
184 .retrans_time
= 1 * HZ
,
185 .gc_staletime
= 60 * HZ
,
186 .reachable_time
= 30 * HZ
,
187 .delay_probe_time
= 5 * HZ
,
191 .anycast_delay
= 1 * HZ
,
192 .proxy_delay
= (8 * HZ
) / 10,
196 .gc_interval
= 30 * HZ
,
201 EXPORT_SYMBOL(arp_tbl
);
203 int arp_mc_map(__be32 addr
, u8
*haddr
, struct net_device
*dev
, int dir
)
209 ip_eth_mc_map(addr
, haddr
);
211 case ARPHRD_IEEE802_TR
:
212 ip_tr_mc_map(addr
, haddr
);
214 case ARPHRD_INFINIBAND
:
215 ip_ib_mc_map(addr
, dev
->broadcast
, haddr
);
218 ip_ipgre_mc_map(addr
, dev
->broadcast
, haddr
);
222 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
230 static u32
arp_hash(const void *pkey
,
231 const struct net_device
*dev
,
234 return arp_hashfn(*(u32
*)pkey
, dev
, hash_rnd
);
237 static int arp_constructor(struct neighbour
*neigh
)
239 __be32 addr
= *(__be32
*)neigh
->primary_key
;
240 struct net_device
*dev
= neigh
->dev
;
241 struct in_device
*in_dev
;
242 struct neigh_parms
*parms
;
245 in_dev
= __in_dev_get_rcu(dev
);
246 if (in_dev
== NULL
) {
251 neigh
->type
= inet_addr_type(dev_net(dev
), addr
);
253 parms
= in_dev
->arp_parms
;
254 __neigh_parms_put(neigh
->parms
);
255 neigh
->parms
= neigh_parms_clone(parms
);
258 if (!dev
->header_ops
) {
259 neigh
->nud_state
= NUD_NOARP
;
260 neigh
->ops
= &arp_direct_ops
;
261 neigh
->output
= neigh
->ops
->queue_xmit
;
263 /* Good devices (checked by reading texts, but only Ethernet is
266 ARPHRD_ETHER: (ethernet, apfddi)
269 ARPHRD_METRICOM: (strip)
273 ARPHRD_IPDDP will also work, if author repairs it.
274 I did not it, because this driver does not work even
279 /* So... these "amateur" devices are hopeless.
280 The only thing, that I can say now:
281 It is very sad that we need to keep ugly obsolete
282 code to make them happy.
284 They should be moved to more reasonable state, now
285 they use rebuild_header INSTEAD OF hard_start_xmit!!!
286 Besides that, they are sort of out of date
287 (a lot of redundant clones/copies, useless in 2.1),
288 I wonder why people believe that they work.
294 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
296 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
299 neigh
->ops
= &arp_broken_ops
;
300 neigh
->output
= neigh
->ops
->output
;
307 if (neigh
->type
== RTN_MULTICAST
) {
308 neigh
->nud_state
= NUD_NOARP
;
309 arp_mc_map(addr
, neigh
->ha
, dev
, 1);
310 } else if (dev
->flags
& (IFF_NOARP
| IFF_LOOPBACK
)) {
311 neigh
->nud_state
= NUD_NOARP
;
312 memcpy(neigh
->ha
, dev
->dev_addr
, dev
->addr_len
);
313 } else if (neigh
->type
== RTN_BROADCAST
||
314 (dev
->flags
& IFF_POINTOPOINT
)) {
315 neigh
->nud_state
= NUD_NOARP
;
316 memcpy(neigh
->ha
, dev
->broadcast
, dev
->addr_len
);
319 if (dev
->header_ops
->cache
)
320 neigh
->ops
= &arp_hh_ops
;
322 neigh
->ops
= &arp_generic_ops
;
324 if (neigh
->nud_state
& NUD_VALID
)
325 neigh
->output
= neigh
->ops
->connected_output
;
327 neigh
->output
= neigh
->ops
->output
;
332 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
)
334 dst_link_failure(skb
);
338 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
)
342 struct net_device
*dev
= neigh
->dev
;
343 __be32 target
= *(__be32
*)neigh
->primary_key
;
344 int probes
= atomic_read(&neigh
->probes
);
345 struct in_device
*in_dev
;
348 in_dev
= __in_dev_get_rcu(dev
);
353 switch (IN_DEV_ARP_ANNOUNCE(in_dev
)) {
355 case 0: /* By default announce any local IP */
356 if (skb
&& inet_addr_type(dev_net(dev
),
357 ip_hdr(skb
)->saddr
) == RTN_LOCAL
)
358 saddr
= ip_hdr(skb
)->saddr
;
360 case 1: /* Restrict announcements of saddr in same subnet */
363 saddr
= ip_hdr(skb
)->saddr
;
364 if (inet_addr_type(dev_net(dev
), saddr
) == RTN_LOCAL
) {
365 /* saddr should be known to target */
366 if (inet_addr_onlink(in_dev
, target
, saddr
))
371 case 2: /* Avoid secondary IPs, get a primary/preferred one */
377 saddr
= inet_select_addr(dev
, target
, RT_SCOPE_LINK
);
379 probes
-= neigh
->parms
->ucast_probes
;
381 if (!(neigh
->nud_state
& NUD_VALID
))
383 "trying to ucast probe in NUD_INVALID\n");
385 read_lock_bh(&neigh
->lock
);
387 probes
-= neigh
->parms
->app_probes
;
396 arp_send(ARPOP_REQUEST
, ETH_P_ARP
, target
, dev
, saddr
,
397 dst_ha
, dev
->dev_addr
, NULL
);
399 read_unlock_bh(&neigh
->lock
);
402 static int arp_ignore(struct in_device
*in_dev
, __be32 sip
, __be32 tip
)
406 switch (IN_DEV_ARP_IGNORE(in_dev
)) {
407 case 0: /* Reply, the tip is already validated */
409 case 1: /* Reply only if tip is configured on the incoming interface */
411 scope
= RT_SCOPE_HOST
;
414 * Reply only if tip is configured on the incoming interface
415 * and is in same subnet as sip
417 scope
= RT_SCOPE_HOST
;
419 case 3: /* Do not reply for scope host addresses */
421 scope
= RT_SCOPE_LINK
;
423 case 4: /* Reserved */
428 case 8: /* Do not reply */
433 return !inet_confirm_addr(in_dev
, sip
, tip
, scope
);
436 static int arp_filter(__be32 sip
, __be32 tip
, struct net_device
*dev
)
440 /*unsigned long now; */
441 struct net
*net
= dev_net(dev
);
443 rt
= ip_route_output(net
, sip
, tip
, 0, 0);
446 if (rt
->dst
.dev
!= dev
) {
447 NET_INC_STATS_BH(net
, LINUX_MIB_ARPFILTER
);
454 /* OBSOLETE FUNCTIONS */
457 * Find an arp mapping in the cache. If not found, post a request.
459 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
460 * even if it exists. It is supposed that skb->dev was mangled
461 * by a virtual device (eql, shaper). Nobody but broken devices
462 * is allowed to use this function, it is scheduled to be removed. --ANK
465 static int arp_set_predefined(int addr_hint
, unsigned char *haddr
,
466 __be32 paddr
, struct net_device
*dev
)
470 printk(KERN_DEBUG
"ARP: arp called for own IP address\n");
471 memcpy(haddr
, dev
->dev_addr
, dev
->addr_len
);
474 arp_mc_map(paddr
, haddr
, dev
, 1);
477 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
484 int arp_find(unsigned char *haddr
, struct sk_buff
*skb
)
486 struct net_device
*dev
= skb
->dev
;
491 printk(KERN_DEBUG
"arp_find is called with dst==NULL\n");
496 paddr
= skb_rtable(skb
)->rt_gateway
;
498 if (arp_set_predefined(inet_addr_type(dev_net(dev
), paddr
), haddr
,
502 n
= __neigh_lookup(&arp_tbl
, &paddr
, dev
, 1);
506 if (n
->nud_state
& NUD_VALID
|| neigh_event_send(n
, skb
) == 0) {
507 neigh_ha_snapshot(haddr
, n
, dev
);
516 EXPORT_SYMBOL(arp_find
);
518 /* END OF OBSOLETE FUNCTIONS */
521 * Check if we can use proxy ARP for this path
523 static inline int arp_fwd_proxy(struct in_device
*in_dev
,
524 struct net_device
*dev
, struct rtable
*rt
)
526 struct in_device
*out_dev
;
529 if (rt
->dst
.dev
== dev
)
532 if (!IN_DEV_PROXY_ARP(in_dev
))
534 imi
= IN_DEV_MEDIUM_ID(in_dev
);
540 /* place to check for proxy_arp for routes */
542 out_dev
= __in_dev_get_rcu(rt
->dst
.dev
);
544 omi
= IN_DEV_MEDIUM_ID(out_dev
);
546 return omi
!= imi
&& omi
!= -1;
550 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
552 * RFC3069 supports proxy arp replies back to the same interface. This
553 * is done to support (ethernet) switch features, like RFC 3069, where
554 * the individual ports are not allowed to communicate with each
555 * other, BUT they are allowed to talk to the upstream router. As
556 * described in RFC 3069, it is possible to allow these hosts to
557 * communicate through the upstream router, by proxy_arp'ing.
559 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
561 * This technology is known by different names:
562 * In RFC 3069 it is called VLAN Aggregation.
563 * Cisco and Allied Telesyn call it Private VLAN.
564 * Hewlett-Packard call it Source-Port filtering or port-isolation.
565 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
568 static inline int arp_fwd_pvlan(struct in_device
*in_dev
,
569 struct net_device
*dev
, struct rtable
*rt
,
570 __be32 sip
, __be32 tip
)
572 /* Private VLAN is only concerned about the same ethernet segment */
573 if (rt
->dst
.dev
!= dev
)
576 /* Don't reply on self probes (often done by windowz boxes)*/
580 if (IN_DEV_PROXY_ARP_PVLAN(in_dev
))
587 * Interface to link layer: send routine and receive handler.
591 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
594 struct sk_buff
*arp_create(int type
, int ptype
, __be32 dest_ip
,
595 struct net_device
*dev
, __be32 src_ip
,
596 const unsigned char *dest_hw
,
597 const unsigned char *src_hw
,
598 const unsigned char *target_hw
)
602 unsigned char *arp_ptr
;
608 skb
= alloc_skb(arp_hdr_len(dev
) + LL_ALLOCATED_SPACE(dev
), GFP_ATOMIC
);
612 skb_reserve(skb
, LL_RESERVED_SPACE(dev
));
613 skb_reset_network_header(skb
);
614 arp
= (struct arphdr
*) skb_put(skb
, arp_hdr_len(dev
));
616 skb
->protocol
= htons(ETH_P_ARP
);
618 src_hw
= dev
->dev_addr
;
620 dest_hw
= dev
->broadcast
;
623 * Fill the device header for the ARP frame
625 if (dev_hard_header(skb
, dev
, ptype
, dest_hw
, src_hw
, skb
->len
) < 0)
629 * Fill out the arp protocol part.
631 * The arp hardware type should match the device type, except for FDDI,
632 * which (according to RFC 1390) should always equal 1 (Ethernet).
635 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
636 * DIX code for the protocol. Make these device structure fields.
640 arp
->ar_hrd
= htons(dev
->type
);
641 arp
->ar_pro
= htons(ETH_P_IP
);
644 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
646 arp
->ar_hrd
= htons(ARPHRD_AX25
);
647 arp
->ar_pro
= htons(AX25_P_IP
);
650 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
652 arp
->ar_hrd
= htons(ARPHRD_NETROM
);
653 arp
->ar_pro
= htons(AX25_P_IP
);
658 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
660 arp
->ar_hrd
= htons(ARPHRD_ETHER
);
661 arp
->ar_pro
= htons(ETH_P_IP
);
664 #if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
665 case ARPHRD_IEEE802_TR
:
666 arp
->ar_hrd
= htons(ARPHRD_IEEE802
);
667 arp
->ar_pro
= htons(ETH_P_IP
);
672 arp
->ar_hln
= dev
->addr_len
;
674 arp
->ar_op
= htons(type
);
676 arp_ptr
= (unsigned char *)(arp
+ 1);
678 memcpy(arp_ptr
, src_hw
, dev
->addr_len
);
679 arp_ptr
+= dev
->addr_len
;
680 memcpy(arp_ptr
, &src_ip
, 4);
682 if (target_hw
!= NULL
)
683 memcpy(arp_ptr
, target_hw
, dev
->addr_len
);
685 memset(arp_ptr
, 0, dev
->addr_len
);
686 arp_ptr
+= dev
->addr_len
;
687 memcpy(arp_ptr
, &dest_ip
, 4);
695 EXPORT_SYMBOL(arp_create
);
698 * Send an arp packet.
700 void arp_xmit(struct sk_buff
*skb
)
702 /* Send it off, maybe filter it using firewalling first. */
703 NF_HOOK(NFPROTO_ARP
, NF_ARP_OUT
, skb
, NULL
, skb
->dev
, dev_queue_xmit
);
705 EXPORT_SYMBOL(arp_xmit
);
708 * Create and send an arp packet.
710 void arp_send(int type
, int ptype
, __be32 dest_ip
,
711 struct net_device
*dev
, __be32 src_ip
,
712 const unsigned char *dest_hw
, const unsigned char *src_hw
,
713 const unsigned char *target_hw
)
718 * No arp on this interface.
721 if (dev
->flags
&IFF_NOARP
)
724 skb
= arp_create(type
, ptype
, dest_ip
, dev
, src_ip
,
725 dest_hw
, src_hw
, target_hw
);
731 EXPORT_SYMBOL(arp_send
);
734 * Process an arp request.
737 static int arp_process(struct sk_buff
*skb
)
739 struct net_device
*dev
= skb
->dev
;
740 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
742 unsigned char *arp_ptr
;
746 u16 dev_type
= dev
->type
;
749 struct net
*net
= dev_net(dev
);
751 /* arp_rcv below verifies the ARP header and verifies the device
762 if (arp
->ar_pro
!= htons(ETH_P_IP
) ||
763 htons(dev_type
) != arp
->ar_hrd
)
767 case ARPHRD_IEEE802_TR
:
771 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
772 * devices, according to RFC 2625) devices will accept ARP
773 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
774 * This is the case also of FDDI, where the RFC 1390 says that
775 * FDDI devices should accept ARP hardware of (1) Ethernet,
776 * however, to be more robust, we'll accept both 1 (Ethernet)
779 if ((arp
->ar_hrd
!= htons(ARPHRD_ETHER
) &&
780 arp
->ar_hrd
!= htons(ARPHRD_IEEE802
)) ||
781 arp
->ar_pro
!= htons(ETH_P_IP
))
785 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
786 arp
->ar_hrd
!= htons(ARPHRD_AX25
))
790 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
791 arp
->ar_hrd
!= htons(ARPHRD_NETROM
))
796 /* Understand only these message types */
798 if (arp
->ar_op
!= htons(ARPOP_REPLY
) &&
799 arp
->ar_op
!= htons(ARPOP_REQUEST
))
805 arp_ptr
= (unsigned char *)(arp
+ 1);
807 arp_ptr
+= dev
->addr_len
;
808 memcpy(&sip
, arp_ptr
, 4);
810 arp_ptr
+= dev
->addr_len
;
811 memcpy(&tip
, arp_ptr
, 4);
813 * Check for bad requests for 127.x.x.x and requests for multicast
814 * addresses. If this is one such, delete it.
816 if (ipv4_is_loopback(tip
) || ipv4_is_multicast(tip
))
820 * Special case: We must set Frame Relay source Q.922 address
822 if (dev_type
== ARPHRD_DLCI
)
823 sha
= dev
->broadcast
;
826 * Process entry. The idea here is we want to send a reply if it is a
827 * request for us or if it is a request for someone else that we hold
828 * a proxy for. We want to add an entry to our cache if it is a reply
829 * to us or if it is a request for our address.
830 * (The assumption for this last is that if someone is requesting our
831 * address, they are probably intending to talk to us, so it saves time
832 * if we cache their address. Their address is also probably not in
833 * our cache, since ours is not in their cache.)
835 * Putting this another way, we only care about replies if they are to
836 * us, in which case we add them to the cache. For requests, we care
837 * about those for us and those for our proxies. We reply to both,
838 * and in the case of requests for us we add the requester to the arp
842 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
844 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
845 inet_addr_type(net
, tip
) == RTN_LOCAL
&&
846 !arp_ignore(in_dev
, sip
, tip
))
847 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
, dev
, tip
, sha
,
852 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
853 ip_route_input_noref(skb
, tip
, sip
, 0, dev
) == 0) {
855 rt
= skb_rtable(skb
);
856 addr_type
= rt
->rt_type
;
858 if (addr_type
== RTN_LOCAL
) {
861 dont_send
= arp_ignore(in_dev
, sip
, tip
);
862 if (!dont_send
&& IN_DEV_ARPFILTER(in_dev
))
863 dont_send
= arp_filter(sip
, tip
, dev
);
865 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
867 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
,
868 dev
, tip
, sha
, dev
->dev_addr
,
874 } else if (IN_DEV_FORWARD(in_dev
)) {
875 if (addr_type
== RTN_UNICAST
&&
876 (arp_fwd_proxy(in_dev
, dev
, rt
) ||
877 arp_fwd_pvlan(in_dev
, dev
, rt
, sip
, tip
) ||
878 pneigh_lookup(&arp_tbl
, net
, &tip
, dev
, 0))) {
879 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
883 if (NEIGH_CB(skb
)->flags
& LOCALLY_ENQUEUED
||
884 skb
->pkt_type
== PACKET_HOST
||
885 in_dev
->arp_parms
->proxy_delay
== 0) {
886 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
,
887 dev
, tip
, sha
, dev
->dev_addr
,
890 pneigh_enqueue(&arp_tbl
,
891 in_dev
->arp_parms
, skb
);
899 /* Update our ARP tables */
901 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 0);
903 if (IPV4_DEVCONF_ALL(dev_net(dev
), ARP_ACCEPT
)) {
904 /* Unsolicited ARP is not accepted by default.
905 It is possible, that this option should be enabled for some
906 devices (strip is candidate)
909 (arp
->ar_op
== htons(ARPOP_REPLY
) ||
910 (arp
->ar_op
== htons(ARPOP_REQUEST
) && tip
== sip
)) &&
911 inet_addr_type(net
, sip
) == RTN_UNICAST
)
912 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 1);
916 int state
= NUD_REACHABLE
;
919 /* If several different ARP replies follows back-to-back,
920 use the FIRST one. It is possible, if several proxy
921 agents are active. Taking the first reply prevents
922 arp trashing and chooses the fastest router.
924 override
= time_after(jiffies
, n
->updated
+ n
->parms
->locktime
);
926 /* Broadcast replies and request packets
927 do not assert neighbour reachability.
929 if (arp
->ar_op
!= htons(ARPOP_REPLY
) ||
930 skb
->pkt_type
!= PACKET_HOST
)
932 neigh_update(n
, sha
, state
,
933 override
? NEIGH_UPDATE_F_OVERRIDE
: 0);
942 static void parp_redo(struct sk_buff
*skb
)
949 * Receive an arp request from the device layer.
952 static int arp_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
953 struct packet_type
*pt
, struct net_device
*orig_dev
)
957 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
958 if (!pskb_may_pull(skb
, arp_hdr_len(dev
)))
962 if (arp
->ar_hln
!= dev
->addr_len
||
963 dev
->flags
& IFF_NOARP
||
964 skb
->pkt_type
== PACKET_OTHERHOST
||
965 skb
->pkt_type
== PACKET_LOOPBACK
||
969 skb
= skb_share_check(skb
, GFP_ATOMIC
);
973 memset(NEIGH_CB(skb
), 0, sizeof(struct neighbour_cb
));
975 return NF_HOOK(NFPROTO_ARP
, NF_ARP_IN
, skb
, dev
, NULL
, arp_process
);
984 * User level interface (ioctl)
988 * Set (create) an ARP cache entry.
991 static int arp_req_set_proxy(struct net
*net
, struct net_device
*dev
, int on
)
994 IPV4_DEVCONF_ALL(net
, PROXY_ARP
) = on
;
997 if (__in_dev_get_rtnl(dev
)) {
998 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev
), PROXY_ARP
, on
);
1004 static int arp_req_set_public(struct net
*net
, struct arpreq
*r
,
1005 struct net_device
*dev
)
1007 __be32 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1008 __be32 mask
= ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1010 if (mask
&& mask
!= htonl(0xFFFFFFFF))
1012 if (!dev
&& (r
->arp_flags
& ATF_COM
)) {
1013 dev
= dev_getbyhwaddr_rcu(net
, r
->arp_ha
.sa_family
,
1019 if (pneigh_lookup(&arp_tbl
, net
, &ip
, dev
, 1) == NULL
)
1024 return arp_req_set_proxy(net
, dev
, 1);
1027 static int arp_req_set(struct net
*net
, struct arpreq
*r
,
1028 struct net_device
*dev
)
1031 struct neighbour
*neigh
;
1034 if (r
->arp_flags
& ATF_PUBL
)
1035 return arp_req_set_public(net
, r
, dev
);
1037 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1038 if (r
->arp_flags
& ATF_PERM
)
1039 r
->arp_flags
|= ATF_COM
;
1041 struct rtable
*rt
= ip_route_output(net
, ip
, 0, RTO_ONLINK
, 0);
1050 switch (dev
->type
) {
1051 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
1054 * According to RFC 1390, FDDI devices should accept ARP
1055 * hardware types of 1 (Ethernet). However, to be more
1056 * robust, we'll accept hardware types of either 1 (Ethernet)
1057 * or 6 (IEEE 802.2).
1059 if (r
->arp_ha
.sa_family
!= ARPHRD_FDDI
&&
1060 r
->arp_ha
.sa_family
!= ARPHRD_ETHER
&&
1061 r
->arp_ha
.sa_family
!= ARPHRD_IEEE802
)
1066 if (r
->arp_ha
.sa_family
!= dev
->type
)
1071 neigh
= __neigh_lookup_errno(&arp_tbl
, &ip
, dev
);
1072 err
= PTR_ERR(neigh
);
1073 if (!IS_ERR(neigh
)) {
1074 unsigned state
= NUD_STALE
;
1075 if (r
->arp_flags
& ATF_PERM
)
1076 state
= NUD_PERMANENT
;
1077 err
= neigh_update(neigh
, (r
->arp_flags
& ATF_COM
) ?
1078 r
->arp_ha
.sa_data
: NULL
, state
,
1079 NEIGH_UPDATE_F_OVERRIDE
|
1080 NEIGH_UPDATE_F_ADMIN
);
1081 neigh_release(neigh
);
1086 static unsigned arp_state_to_flags(struct neighbour
*neigh
)
1088 if (neigh
->nud_state
&NUD_PERMANENT
)
1089 return ATF_PERM
| ATF_COM
;
1090 else if (neigh
->nud_state
&NUD_VALID
)
1097 * Get an ARP cache entry.
1100 static int arp_req_get(struct arpreq
*r
, struct net_device
*dev
)
1102 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1103 struct neighbour
*neigh
;
1106 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1108 read_lock_bh(&neigh
->lock
);
1109 memcpy(r
->arp_ha
.sa_data
, neigh
->ha
, dev
->addr_len
);
1110 r
->arp_flags
= arp_state_to_flags(neigh
);
1111 read_unlock_bh(&neigh
->lock
);
1112 r
->arp_ha
.sa_family
= dev
->type
;
1113 strlcpy(r
->arp_dev
, dev
->name
, sizeof(r
->arp_dev
));
1114 neigh_release(neigh
);
1120 int arp_invalidate(struct net_device
*dev
, __be32 ip
)
1122 struct neighbour
*neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1126 if (neigh
->nud_state
& ~NUD_NOARP
)
1127 err
= neigh_update(neigh
, NULL
, NUD_FAILED
,
1128 NEIGH_UPDATE_F_OVERRIDE
|
1129 NEIGH_UPDATE_F_ADMIN
);
1130 neigh_release(neigh
);
1135 EXPORT_SYMBOL(arp_invalidate
);
1137 static int arp_req_delete_public(struct net
*net
, struct arpreq
*r
,
1138 struct net_device
*dev
)
1140 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1141 __be32 mask
= ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1143 if (mask
== htonl(0xFFFFFFFF))
1144 return pneigh_delete(&arp_tbl
, net
, &ip
, dev
);
1149 return arp_req_set_proxy(net
, dev
, 0);
1152 static int arp_req_delete(struct net
*net
, struct arpreq
*r
,
1153 struct net_device
*dev
)
1157 if (r
->arp_flags
& ATF_PUBL
)
1158 return arp_req_delete_public(net
, r
, dev
);
1160 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1162 struct rtable
*rt
= ip_route_output(net
, ip
, 0, RTO_ONLINK
, 0);
1170 return arp_invalidate(dev
, ip
);
1174 * Handle an ARP layer I/O control request.
1177 int arp_ioctl(struct net
*net
, unsigned int cmd
, void __user
*arg
)
1181 struct net_device
*dev
= NULL
;
1186 if (!capable(CAP_NET_ADMIN
))
1189 err
= copy_from_user(&r
, arg
, sizeof(struct arpreq
));
1197 if (r
.arp_pa
.sa_family
!= AF_INET
)
1198 return -EPFNOSUPPORT
;
1200 if (!(r
.arp_flags
& ATF_PUBL
) &&
1201 (r
.arp_flags
& (ATF_NETMASK
| ATF_DONTPUB
)))
1203 if (!(r
.arp_flags
& ATF_NETMASK
))
1204 ((struct sockaddr_in
*)&r
.arp_netmask
)->sin_addr
.s_addr
=
1205 htonl(0xFFFFFFFFUL
);
1209 dev
= __dev_get_by_name(net
, r
.arp_dev
);
1213 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1214 if (!r
.arp_ha
.sa_family
)
1215 r
.arp_ha
.sa_family
= dev
->type
;
1217 if ((r
.arp_flags
& ATF_COM
) && r
.arp_ha
.sa_family
!= dev
->type
)
1219 } else if (cmd
== SIOCGARP
) {
1226 err
= arp_req_delete(net
, &r
, dev
);
1229 err
= arp_req_set(net
, &r
, dev
);
1232 err
= arp_req_get(&r
, dev
);
1237 if (cmd
== SIOCGARP
&& !err
&& copy_to_user(arg
, &r
, sizeof(r
)))
1242 static int arp_netdev_event(struct notifier_block
*this, unsigned long event
,
1245 struct net_device
*dev
= ptr
;
1248 case NETDEV_CHANGEADDR
:
1249 neigh_changeaddr(&arp_tbl
, dev
);
1250 rt_cache_flush(dev_net(dev
), 0);
1259 static struct notifier_block arp_netdev_notifier
= {
1260 .notifier_call
= arp_netdev_event
,
1263 /* Note, that it is not on notifier chain.
1264 It is necessary, that this routine was called after route cache will be
1267 void arp_ifdown(struct net_device
*dev
)
1269 neigh_ifdown(&arp_tbl
, dev
);
1274 * Called once on startup.
1277 static struct packet_type arp_packet_type __read_mostly
= {
1278 .type
= cpu_to_be16(ETH_P_ARP
),
1282 static int arp_proc_init(void);
1284 void __init
arp_init(void)
1286 neigh_table_init(&arp_tbl
);
1288 dev_add_pack(&arp_packet_type
);
1290 #ifdef CONFIG_SYSCTL
1291 neigh_sysctl_register(NULL
, &arp_tbl
.parms
, "ipv4", NULL
);
1293 register_netdevice_notifier(&arp_netdev_notifier
);
1296 #ifdef CONFIG_PROC_FS
1297 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1299 /* ------------------------------------------------------------------------ */
1301 * ax25 -> ASCII conversion
1303 static char *ax2asc2(ax25_address
*a
, char *buf
)
1308 for (n
= 0, s
= buf
; n
< 6; n
++) {
1309 c
= (a
->ax25_call
[n
] >> 1) & 0x7F;
1316 n
= (a
->ax25_call
[6] >> 1) & 0x0F;
1325 if (*buf
== '\0' || *buf
== '-')
1330 #endif /* CONFIG_AX25 */
1332 #define HBUFFERLEN 30
1334 static void arp_format_neigh_entry(struct seq_file
*seq
,
1335 struct neighbour
*n
)
1337 char hbuffer
[HBUFFERLEN
];
1340 struct net_device
*dev
= n
->dev
;
1341 int hatype
= dev
->type
;
1343 read_lock(&n
->lock
);
1344 /* Convert hardware address to XX:XX:XX:XX ... form. */
1345 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1346 if (hatype
== ARPHRD_AX25
|| hatype
== ARPHRD_NETROM
)
1347 ax2asc2((ax25_address
*)n
->ha
, hbuffer
);
1350 for (k
= 0, j
= 0; k
< HBUFFERLEN
- 3 && j
< dev
->addr_len
; j
++) {
1351 hbuffer
[k
++] = hex_asc_hi(n
->ha
[j
]);
1352 hbuffer
[k
++] = hex_asc_lo(n
->ha
[j
]);
1358 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1361 sprintf(tbuf
, "%pI4", n
->primary_key
);
1362 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1363 tbuf
, hatype
, arp_state_to_flags(n
), hbuffer
, dev
->name
);
1364 read_unlock(&n
->lock
);
1367 static void arp_format_pneigh_entry(struct seq_file
*seq
,
1368 struct pneigh_entry
*n
)
1370 struct net_device
*dev
= n
->dev
;
1371 int hatype
= dev
? dev
->type
: 0;
1374 sprintf(tbuf
, "%pI4", n
->key
);
1375 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1376 tbuf
, hatype
, ATF_PUBL
| ATF_PERM
, "00:00:00:00:00:00",
1377 dev
? dev
->name
: "*");
1380 static int arp_seq_show(struct seq_file
*seq
, void *v
)
1382 if (v
== SEQ_START_TOKEN
) {
1383 seq_puts(seq
, "IP address HW type Flags "
1384 "HW address Mask Device\n");
1386 struct neigh_seq_state
*state
= seq
->private;
1388 if (state
->flags
& NEIGH_SEQ_IS_PNEIGH
)
1389 arp_format_pneigh_entry(seq
, v
);
1391 arp_format_neigh_entry(seq
, v
);
1397 static void *arp_seq_start(struct seq_file
*seq
, loff_t
*pos
)
1399 /* Don't want to confuse "arp -a" w/ magic entries,
1400 * so we tell the generic iterator to skip NUD_NOARP.
1402 return neigh_seq_start(seq
, pos
, &arp_tbl
, NEIGH_SEQ_SKIP_NOARP
);
1405 /* ------------------------------------------------------------------------ */
1407 static const struct seq_operations arp_seq_ops
= {
1408 .start
= arp_seq_start
,
1409 .next
= neigh_seq_next
,
1410 .stop
= neigh_seq_stop
,
1411 .show
= arp_seq_show
,
1414 static int arp_seq_open(struct inode
*inode
, struct file
*file
)
1416 return seq_open_net(inode
, file
, &arp_seq_ops
,
1417 sizeof(struct neigh_seq_state
));
1420 static const struct file_operations arp_seq_fops
= {
1421 .owner
= THIS_MODULE
,
1422 .open
= arp_seq_open
,
1424 .llseek
= seq_lseek
,
1425 .release
= seq_release_net
,
1429 static int __net_init
arp_net_init(struct net
*net
)
1431 if (!proc_net_fops_create(net
, "arp", S_IRUGO
, &arp_seq_fops
))
1436 static void __net_exit
arp_net_exit(struct net
*net
)
1438 proc_net_remove(net
, "arp");
1441 static struct pernet_operations arp_net_ops
= {
1442 .init
= arp_net_init
,
1443 .exit
= arp_net_exit
,
1446 static int __init
arp_proc_init(void)
1448 return register_pernet_subsys(&arp_net_ops
);
1451 #else /* CONFIG_PROC_FS */
1453 static int __init
arp_proc_init(void)
1458 #endif /* CONFIG_PROC_FS */