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/jhash.h>
101 #include <linux/slab.h>
103 #include <linux/sysctl.h>
106 #include <net/net_namespace.h>
108 #include <net/icmp.h>
109 #include <net/route.h>
110 #include <net/protocol.h>
112 #include <net/sock.h>
114 #include <net/ax25.h>
115 #include <net/netrom.h>
116 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
117 #include <net/atmclip.h>
118 struct neigh_table
*clip_tbl_hook
;
119 EXPORT_SYMBOL(clip_tbl_hook
);
122 #include <asm/system.h>
123 #include <asm/uaccess.h>
125 #include <linux/netfilter_arp.h>
128 * Interface to generic neighbour cache.
130 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
);
131 static int arp_constructor(struct neighbour
*neigh
);
132 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
);
133 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
);
134 static void parp_redo(struct sk_buff
*skb
);
136 static const struct neigh_ops arp_generic_ops
= {
138 .solicit
= arp_solicit
,
139 .error_report
= arp_error_report
,
140 .output
= neigh_resolve_output
,
141 .connected_output
= neigh_connected_output
,
142 .hh_output
= dev_queue_xmit
,
143 .queue_xmit
= dev_queue_xmit
,
146 static const struct neigh_ops arp_hh_ops
= {
148 .solicit
= arp_solicit
,
149 .error_report
= arp_error_report
,
150 .output
= neigh_resolve_output
,
151 .connected_output
= neigh_resolve_output
,
152 .hh_output
= dev_queue_xmit
,
153 .queue_xmit
= dev_queue_xmit
,
156 static const struct neigh_ops arp_direct_ops
= {
158 .output
= dev_queue_xmit
,
159 .connected_output
= dev_queue_xmit
,
160 .hh_output
= dev_queue_xmit
,
161 .queue_xmit
= dev_queue_xmit
,
164 const struct neigh_ops arp_broken_ops
= {
166 .solicit
= arp_solicit
,
167 .error_report
= arp_error_report
,
168 .output
= neigh_compat_output
,
169 .connected_output
= neigh_compat_output
,
170 .hh_output
= dev_queue_xmit
,
171 .queue_xmit
= dev_queue_xmit
,
173 EXPORT_SYMBOL(arp_broken_ops
);
175 struct neigh_table arp_tbl
= {
177 .entry_size
= sizeof(struct neighbour
) + 4,
180 .constructor
= arp_constructor
,
181 .proxy_redo
= parp_redo
,
185 .base_reachable_time
= 30 * HZ
,
186 .retrans_time
= 1 * HZ
,
187 .gc_staletime
= 60 * HZ
,
188 .reachable_time
= 30 * HZ
,
189 .delay_probe_time
= 5 * HZ
,
193 .anycast_delay
= 1 * HZ
,
194 .proxy_delay
= (8 * HZ
) / 10,
198 .gc_interval
= 30 * HZ
,
203 EXPORT_SYMBOL(arp_tbl
);
205 int arp_mc_map(__be32 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
);
216 case ARPHRD_INFINIBAND
:
217 ip_ib_mc_map(addr
, dev
->broadcast
, haddr
);
221 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
229 static u32
arp_hash(const void *pkey
, const struct net_device
*dev
)
231 return jhash_2words(*(u32
*)pkey
, dev
->ifindex
, arp_tbl
.hash_rnd
);
234 static int arp_constructor(struct neighbour
*neigh
)
236 __be32 addr
= *(__be32
*)neigh
->primary_key
;
237 struct net_device
*dev
= neigh
->dev
;
238 struct in_device
*in_dev
;
239 struct neigh_parms
*parms
;
242 in_dev
= __in_dev_get_rcu(dev
);
243 if (in_dev
== NULL
) {
248 neigh
->type
= inet_addr_type(dev_net(dev
), addr
);
250 parms
= in_dev
->arp_parms
;
251 __neigh_parms_put(neigh
->parms
);
252 neigh
->parms
= neigh_parms_clone(parms
);
255 if (!dev
->header_ops
) {
256 neigh
->nud_state
= NUD_NOARP
;
257 neigh
->ops
= &arp_direct_ops
;
258 neigh
->output
= neigh
->ops
->queue_xmit
;
260 /* Good devices (checked by reading texts, but only Ethernet is
263 ARPHRD_ETHER: (ethernet, apfddi)
266 ARPHRD_METRICOM: (strip)
270 ARPHRD_IPDDP will also work, if author repairs it.
271 I did not it, because this driver does not work even
275 /* So... these "amateur" devices are hopeless.
276 The only thing, that I can say now:
277 It is very sad that we need to keep ugly obsolete
278 code to make them happy.
280 They should be moved to more reasonable state, now
281 they use rebuild_header INSTEAD OF hard_start_xmit!!!
282 Besides that, they are sort of out of date
283 (a lot of redundant clones/copies, useless in 2.1),
284 I wonder why people believe that they work.
290 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
292 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
295 neigh
->ops
= &arp_broken_ops
;
296 neigh
->output
= neigh
->ops
->output
;
300 if (neigh
->type
== RTN_MULTICAST
) {
301 neigh
->nud_state
= NUD_NOARP
;
302 arp_mc_map(addr
, neigh
->ha
, dev
, 1);
303 } else if (dev
->flags
&(IFF_NOARP
|IFF_LOOPBACK
)) {
304 neigh
->nud_state
= NUD_NOARP
;
305 memcpy(neigh
->ha
, dev
->dev_addr
, dev
->addr_len
);
306 } else if (neigh
->type
== RTN_BROADCAST
|| dev
->flags
&IFF_POINTOPOINT
) {
307 neigh
->nud_state
= NUD_NOARP
;
308 memcpy(neigh
->ha
, dev
->broadcast
, dev
->addr_len
);
311 if (dev
->header_ops
->cache
)
312 neigh
->ops
= &arp_hh_ops
;
314 neigh
->ops
= &arp_generic_ops
;
316 if (neigh
->nud_state
&NUD_VALID
)
317 neigh
->output
= neigh
->ops
->connected_output
;
319 neigh
->output
= neigh
->ops
->output
;
324 static void arp_error_report(struct neighbour
*neigh
, struct sk_buff
*skb
)
326 dst_link_failure(skb
);
330 static void arp_solicit(struct neighbour
*neigh
, struct sk_buff
*skb
)
334 struct net_device
*dev
= neigh
->dev
;
335 __be32 target
= *(__be32
*)neigh
->primary_key
;
336 int probes
= atomic_read(&neigh
->probes
);
337 struct in_device
*in_dev
;
340 in_dev
= __in_dev_get_rcu(dev
);
345 switch (IN_DEV_ARP_ANNOUNCE(in_dev
)) {
347 case 0: /* By default announce any local IP */
348 if (skb
&& inet_addr_type(dev_net(dev
), 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 if ((probes
-= neigh
->parms
->ucast_probes
) < 0) {
371 if (!(neigh
->nud_state
&NUD_VALID
))
372 printk(KERN_DEBUG
"trying to ucast probe in NUD_INVALID\n");
374 read_lock_bh(&neigh
->lock
);
375 } else if ((probes
-= neigh
->parms
->app_probes
) < 0) {
382 arp_send(ARPOP_REQUEST
, ETH_P_ARP
, target
, dev
, saddr
,
383 dst_ha
, dev
->dev_addr
, NULL
);
385 read_unlock_bh(&neigh
->lock
);
388 static int arp_ignore(struct in_device
*in_dev
, __be32 sip
, __be32 tip
)
392 switch (IN_DEV_ARP_IGNORE(in_dev
)) {
393 case 0: /* Reply, the tip is already validated */
395 case 1: /* Reply only if tip is configured on the incoming interface */
397 scope
= RT_SCOPE_HOST
;
400 * Reply only if tip is configured on the incoming interface
401 * and is in same subnet as sip
403 scope
= RT_SCOPE_HOST
;
405 case 3: /* Do not reply for scope host addresses */
407 scope
= RT_SCOPE_LINK
;
409 case 4: /* Reserved */
414 case 8: /* Do not reply */
419 return !inet_confirm_addr(in_dev
, sip
, tip
, scope
);
422 static int arp_filter(__be32 sip
, __be32 tip
, struct net_device
*dev
)
424 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= sip
,
428 /*unsigned long now; */
429 struct net
*net
= dev_net(dev
);
431 if (ip_route_output_key(net
, &rt
, &fl
) < 0)
433 if (rt
->dst
.dev
!= dev
) {
434 NET_INC_STATS_BH(net
, LINUX_MIB_ARPFILTER
);
441 /* OBSOLETE FUNCTIONS */
444 * Find an arp mapping in the cache. If not found, post a request.
446 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
447 * even if it exists. It is supposed that skb->dev was mangled
448 * by a virtual device (eql, shaper). Nobody but broken devices
449 * is allowed to use this function, it is scheduled to be removed. --ANK
452 static int arp_set_predefined(int addr_hint
, unsigned char * haddr
, __be32 paddr
, struct net_device
* dev
)
456 printk(KERN_DEBUG
"ARP: arp called for own IP address\n");
457 memcpy(haddr
, dev
->dev_addr
, dev
->addr_len
);
460 arp_mc_map(paddr
, haddr
, dev
, 1);
463 memcpy(haddr
, dev
->broadcast
, dev
->addr_len
);
470 int arp_find(unsigned char *haddr
, struct sk_buff
*skb
)
472 struct net_device
*dev
= skb
->dev
;
477 printk(KERN_DEBUG
"arp_find is called with dst==NULL\n");
482 paddr
= skb_rtable(skb
)->rt_gateway
;
484 if (arp_set_predefined(inet_addr_type(dev_net(dev
), paddr
), haddr
, paddr
, dev
))
487 n
= __neigh_lookup(&arp_tbl
, &paddr
, dev
, 1);
491 if (n
->nud_state
&NUD_VALID
|| neigh_event_send(n
, skb
) == 0) {
492 read_lock_bh(&n
->lock
);
493 memcpy(haddr
, n
->ha
, dev
->addr_len
);
494 read_unlock_bh(&n
->lock
);
503 EXPORT_SYMBOL(arp_find
);
505 /* END OF OBSOLETE FUNCTIONS */
507 int arp_bind_neighbour(struct dst_entry
*dst
)
509 struct net_device
*dev
= dst
->dev
;
510 struct neighbour
*n
= dst
->neighbour
;
515 __be32 nexthop
= ((struct rtable
*)dst
)->rt_gateway
;
516 if (dev
->flags
&(IFF_LOOPBACK
|IFF_POINTOPOINT
))
518 n
= __neigh_lookup_errno(
519 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
520 dev
->type
== ARPHRD_ATM
? clip_tbl_hook
:
522 &arp_tbl
, &nexthop
, dev
);
531 * Check if we can use proxy ARP for this path
533 static inline int arp_fwd_proxy(struct in_device
*in_dev
,
534 struct net_device
*dev
, struct rtable
*rt
)
536 struct in_device
*out_dev
;
539 if (rt
->dst
.dev
== dev
)
542 if (!IN_DEV_PROXY_ARP(in_dev
))
545 if ((imi
= IN_DEV_MEDIUM_ID(in_dev
)) == 0)
550 /* place to check for proxy_arp for routes */
552 out_dev
= __in_dev_get_rcu(rt
->dst
.dev
);
554 omi
= IN_DEV_MEDIUM_ID(out_dev
);
556 return (omi
!= imi
&& omi
!= -1);
560 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
562 * RFC3069 supports proxy arp replies back to the same interface. This
563 * is done to support (ethernet) switch features, like RFC 3069, where
564 * the individual ports are not allowed to communicate with each
565 * other, BUT they are allowed to talk to the upstream router. As
566 * described in RFC 3069, it is possible to allow these hosts to
567 * communicate through the upstream router, by proxy_arp'ing.
569 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
571 * This technology is known by different names:
572 * In RFC 3069 it is called VLAN Aggregation.
573 * Cisco and Allied Telesyn call it Private VLAN.
574 * Hewlett-Packard call it Source-Port filtering or port-isolation.
575 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
578 static inline int arp_fwd_pvlan(struct in_device
*in_dev
,
579 struct net_device
*dev
, struct rtable
*rt
,
580 __be32 sip
, __be32 tip
)
582 /* Private VLAN is only concerned about the same ethernet segment */
583 if (rt
->dst
.dev
!= dev
)
586 /* Don't reply on self probes (often done by windowz boxes)*/
590 if (IN_DEV_PROXY_ARP_PVLAN(in_dev
))
597 * Interface to link layer: send routine and receive handler.
601 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
604 struct sk_buff
*arp_create(int type
, int ptype
, __be32 dest_ip
,
605 struct net_device
*dev
, __be32 src_ip
,
606 const unsigned char *dest_hw
,
607 const unsigned char *src_hw
,
608 const unsigned char *target_hw
)
612 unsigned char *arp_ptr
;
618 skb
= alloc_skb(arp_hdr_len(dev
) + LL_ALLOCATED_SPACE(dev
), GFP_ATOMIC
);
622 skb_reserve(skb
, LL_RESERVED_SPACE(dev
));
623 skb_reset_network_header(skb
);
624 arp
= (struct arphdr
*) skb_put(skb
, arp_hdr_len(dev
));
626 skb
->protocol
= htons(ETH_P_ARP
);
628 src_hw
= dev
->dev_addr
;
630 dest_hw
= dev
->broadcast
;
633 * Fill the device header for the ARP frame
635 if (dev_hard_header(skb
, dev
, ptype
, dest_hw
, src_hw
, skb
->len
) < 0)
639 * Fill out the arp protocol part.
641 * The arp hardware type should match the device type, except for FDDI,
642 * which (according to RFC 1390) should always equal 1 (Ethernet).
645 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
646 * DIX code for the protocol. Make these device structure fields.
650 arp
->ar_hrd
= htons(dev
->type
);
651 arp
->ar_pro
= htons(ETH_P_IP
);
654 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
656 arp
->ar_hrd
= htons(ARPHRD_AX25
);
657 arp
->ar_pro
= htons(AX25_P_IP
);
660 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
662 arp
->ar_hrd
= htons(ARPHRD_NETROM
);
663 arp
->ar_pro
= htons(AX25_P_IP
);
668 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
670 arp
->ar_hrd
= htons(ARPHRD_ETHER
);
671 arp
->ar_pro
= htons(ETH_P_IP
);
674 #if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
675 case ARPHRD_IEEE802_TR
:
676 arp
->ar_hrd
= htons(ARPHRD_IEEE802
);
677 arp
->ar_pro
= htons(ETH_P_IP
);
682 arp
->ar_hln
= dev
->addr_len
;
684 arp
->ar_op
= htons(type
);
686 arp_ptr
=(unsigned char *)(arp
+1);
688 memcpy(arp_ptr
, src_hw
, dev
->addr_len
);
689 arp_ptr
+= dev
->addr_len
;
690 memcpy(arp_ptr
, &src_ip
, 4);
692 if (target_hw
!= NULL
)
693 memcpy(arp_ptr
, target_hw
, dev
->addr_len
);
695 memset(arp_ptr
, 0, dev
->addr_len
);
696 arp_ptr
+= dev
->addr_len
;
697 memcpy(arp_ptr
, &dest_ip
, 4);
705 EXPORT_SYMBOL(arp_create
);
708 * Send an arp packet.
710 void arp_xmit(struct sk_buff
*skb
)
712 /* Send it off, maybe filter it using firewalling first. */
713 NF_HOOK(NFPROTO_ARP
, NF_ARP_OUT
, skb
, NULL
, skb
->dev
, dev_queue_xmit
);
715 EXPORT_SYMBOL(arp_xmit
);
718 * Create and send an arp packet.
720 void arp_send(int type
, int ptype
, __be32 dest_ip
,
721 struct net_device
*dev
, __be32 src_ip
,
722 const unsigned char *dest_hw
, const unsigned char *src_hw
,
723 const unsigned char *target_hw
)
728 * No arp on this interface.
731 if (dev
->flags
&IFF_NOARP
)
734 skb
= arp_create(type
, ptype
, dest_ip
, dev
, src_ip
,
735 dest_hw
, src_hw
, target_hw
);
742 EXPORT_SYMBOL(arp_send
);
745 * Process an arp request.
748 static int arp_process(struct sk_buff
*skb
)
750 struct net_device
*dev
= skb
->dev
;
751 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
753 unsigned char *arp_ptr
;
757 u16 dev_type
= dev
->type
;
760 struct net
*net
= dev_net(dev
);
762 /* arp_rcv below verifies the ARP header and verifies the device
773 if (arp
->ar_pro
!= htons(ETH_P_IP
) ||
774 htons(dev_type
) != arp
->ar_hrd
)
778 case ARPHRD_IEEE802_TR
:
782 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
783 * devices, according to RFC 2625) devices will accept ARP
784 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
785 * This is the case also of FDDI, where the RFC 1390 says that
786 * FDDI devices should accept ARP hardware of (1) Ethernet,
787 * however, to be more robust, we'll accept both 1 (Ethernet)
790 if ((arp
->ar_hrd
!= htons(ARPHRD_ETHER
) &&
791 arp
->ar_hrd
!= htons(ARPHRD_IEEE802
)) ||
792 arp
->ar_pro
!= htons(ETH_P_IP
))
796 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
797 arp
->ar_hrd
!= htons(ARPHRD_AX25
))
801 if (arp
->ar_pro
!= htons(AX25_P_IP
) ||
802 arp
->ar_hrd
!= htons(ARPHRD_NETROM
))
807 /* Understand only these message types */
809 if (arp
->ar_op
!= htons(ARPOP_REPLY
) &&
810 arp
->ar_op
!= htons(ARPOP_REQUEST
))
816 arp_ptr
= (unsigned char *)(arp
+1);
818 arp_ptr
+= dev
->addr_len
;
819 memcpy(&sip
, arp_ptr
, 4);
821 arp_ptr
+= dev
->addr_len
;
822 memcpy(&tip
, arp_ptr
, 4);
824 * Check for bad requests for 127.x.x.x and requests for multicast
825 * addresses. If this is one such, delete it.
827 if (ipv4_is_loopback(tip
) || ipv4_is_multicast(tip
))
831 * Special case: We must set Frame Relay source Q.922 address
833 if (dev_type
== ARPHRD_DLCI
)
834 sha
= dev
->broadcast
;
837 * Process entry. The idea here is we want to send a reply if it is a
838 * request for us or if it is a request for someone else that we hold
839 * a proxy for. We want to add an entry to our cache if it is a reply
840 * to us or if it is a request for our address.
841 * (The assumption for this last is that if someone is requesting our
842 * address, they are probably intending to talk to us, so it saves time
843 * if we cache their address. Their address is also probably not in
844 * our cache, since ours is not in their cache.)
846 * Putting this another way, we only care about replies if they are to
847 * us, in which case we add them to the cache. For requests, we care
848 * about those for us and those for our proxies. We reply to both,
849 * and in the case of requests for us we add the requester to the arp
853 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
855 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
856 inet_addr_type(net
, tip
) == RTN_LOCAL
&&
857 !arp_ignore(in_dev
, sip
, tip
))
858 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
, dev
, tip
, sha
,
863 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
864 ip_route_input_noref(skb
, tip
, sip
, 0, dev
) == 0) {
866 rt
= skb_rtable(skb
);
867 addr_type
= rt
->rt_type
;
869 if (addr_type
== RTN_LOCAL
) {
873 dont_send
|= arp_ignore(in_dev
,sip
,tip
);
874 if (!dont_send
&& IN_DEV_ARPFILTER(in_dev
))
875 dont_send
|= arp_filter(sip
,tip
,dev
);
877 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
879 arp_send(ARPOP_REPLY
,ETH_P_ARP
,sip
,dev
,tip
,sha
,dev
->dev_addr
,sha
);
884 } else if (IN_DEV_FORWARD(in_dev
)) {
885 if (addr_type
== RTN_UNICAST
&&
886 (arp_fwd_proxy(in_dev
, dev
, rt
) ||
887 arp_fwd_pvlan(in_dev
, dev
, rt
, sip
, tip
) ||
888 pneigh_lookup(&arp_tbl
, net
, &tip
, dev
, 0)))
890 n
= neigh_event_ns(&arp_tbl
, sha
, &sip
, dev
);
894 if (NEIGH_CB(skb
)->flags
& LOCALLY_ENQUEUED
||
895 skb
->pkt_type
== PACKET_HOST
||
896 in_dev
->arp_parms
->proxy_delay
== 0) {
897 arp_send(ARPOP_REPLY
,ETH_P_ARP
,sip
,dev
,tip
,sha
,dev
->dev_addr
,sha
);
899 pneigh_enqueue(&arp_tbl
, in_dev
->arp_parms
, skb
);
907 /* Update our ARP tables */
909 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 0);
911 if (IPV4_DEVCONF_ALL(dev_net(dev
), ARP_ACCEPT
)) {
912 /* Unsolicited ARP is not accepted by default.
913 It is possible, that this option should be enabled for some
914 devices (strip is candidate)
917 (arp
->ar_op
== htons(ARPOP_REPLY
) ||
918 (arp
->ar_op
== htons(ARPOP_REQUEST
) && tip
== sip
)) &&
919 inet_addr_type(net
, sip
) == RTN_UNICAST
)
920 n
= __neigh_lookup(&arp_tbl
, &sip
, dev
, 1);
924 int state
= NUD_REACHABLE
;
927 /* If several different ARP replies follows back-to-back,
928 use the FIRST one. It is possible, if several proxy
929 agents are active. Taking the first reply prevents
930 arp trashing and chooses the fastest router.
932 override
= time_after(jiffies
, n
->updated
+ n
->parms
->locktime
);
934 /* Broadcast replies and request packets
935 do not assert neighbour reachability.
937 if (arp
->ar_op
!= htons(ARPOP_REPLY
) ||
938 skb
->pkt_type
!= PACKET_HOST
)
940 neigh_update(n
, sha
, state
, override
? NEIGH_UPDATE_F_OVERRIDE
: 0);
949 static void parp_redo(struct sk_buff
*skb
)
956 * Receive an arp request from the device layer.
959 static int arp_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
960 struct packet_type
*pt
, struct net_device
*orig_dev
)
964 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
965 if (!pskb_may_pull(skb
, arp_hdr_len(dev
)))
969 if (arp
->ar_hln
!= dev
->addr_len
||
970 dev
->flags
& IFF_NOARP
||
971 skb
->pkt_type
== PACKET_OTHERHOST
||
972 skb
->pkt_type
== PACKET_LOOPBACK
||
976 if ((skb
= skb_share_check(skb
, GFP_ATOMIC
)) == NULL
)
979 memset(NEIGH_CB(skb
), 0, sizeof(struct neighbour_cb
));
981 return NF_HOOK(NFPROTO_ARP
, NF_ARP_IN
, skb
, dev
, NULL
, arp_process
);
990 * User level interface (ioctl)
994 * Set (create) an ARP cache entry.
997 static int arp_req_set_proxy(struct net
*net
, struct net_device
*dev
, int on
)
1000 IPV4_DEVCONF_ALL(net
, PROXY_ARP
) = on
;
1003 if (__in_dev_get_rtnl(dev
)) {
1004 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev
), PROXY_ARP
, on
);
1010 static int arp_req_set_public(struct net
*net
, struct arpreq
*r
,
1011 struct net_device
*dev
)
1013 __be32 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1014 __be32 mask
= ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1016 if (mask
&& mask
!= htonl(0xFFFFFFFF))
1018 if (!dev
&& (r
->arp_flags
& ATF_COM
)) {
1019 dev
= dev_getbyhwaddr(net
, r
->arp_ha
.sa_family
,
1025 if (pneigh_lookup(&arp_tbl
, net
, &ip
, dev
, 1) == NULL
)
1030 return arp_req_set_proxy(net
, dev
, 1);
1033 static int arp_req_set(struct net
*net
, struct arpreq
*r
,
1034 struct net_device
* dev
)
1037 struct neighbour
*neigh
;
1040 if (r
->arp_flags
& ATF_PUBL
)
1041 return arp_req_set_public(net
, r
, dev
);
1043 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1044 if (r
->arp_flags
& ATF_PERM
)
1045 r
->arp_flags
|= ATF_COM
;
1047 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= ip
,
1048 .tos
= RTO_ONLINK
} } };
1050 if ((err
= ip_route_output_key(net
, &rt
, &fl
)) != 0)
1057 switch (dev
->type
) {
1058 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
1061 * According to RFC 1390, FDDI devices should accept ARP
1062 * hardware types of 1 (Ethernet). However, to be more
1063 * robust, we'll accept hardware types of either 1 (Ethernet)
1064 * or 6 (IEEE 802.2).
1066 if (r
->arp_ha
.sa_family
!= ARPHRD_FDDI
&&
1067 r
->arp_ha
.sa_family
!= ARPHRD_ETHER
&&
1068 r
->arp_ha
.sa_family
!= ARPHRD_IEEE802
)
1073 if (r
->arp_ha
.sa_family
!= dev
->type
)
1078 neigh
= __neigh_lookup_errno(&arp_tbl
, &ip
, dev
);
1079 err
= PTR_ERR(neigh
);
1080 if (!IS_ERR(neigh
)) {
1081 unsigned state
= NUD_STALE
;
1082 if (r
->arp_flags
& ATF_PERM
)
1083 state
= NUD_PERMANENT
;
1084 err
= neigh_update(neigh
, (r
->arp_flags
&ATF_COM
) ?
1085 r
->arp_ha
.sa_data
: NULL
, state
,
1086 NEIGH_UPDATE_F_OVERRIDE
|
1087 NEIGH_UPDATE_F_ADMIN
);
1088 neigh_release(neigh
);
1093 static unsigned arp_state_to_flags(struct neighbour
*neigh
)
1096 if (neigh
->nud_state
&NUD_PERMANENT
)
1097 flags
= ATF_PERM
|ATF_COM
;
1098 else if (neigh
->nud_state
&NUD_VALID
)
1104 * Get an ARP cache entry.
1107 static int arp_req_get(struct arpreq
*r
, struct net_device
*dev
)
1109 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1110 struct neighbour
*neigh
;
1113 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1115 read_lock_bh(&neigh
->lock
);
1116 memcpy(r
->arp_ha
.sa_data
, neigh
->ha
, dev
->addr_len
);
1117 r
->arp_flags
= arp_state_to_flags(neigh
);
1118 read_unlock_bh(&neigh
->lock
);
1119 r
->arp_ha
.sa_family
= dev
->type
;
1120 strlcpy(r
->arp_dev
, dev
->name
, sizeof(r
->arp_dev
));
1121 neigh_release(neigh
);
1127 static int arp_req_delete_public(struct net
*net
, struct arpreq
*r
,
1128 struct net_device
*dev
)
1130 __be32 ip
= ((struct sockaddr_in
*) &r
->arp_pa
)->sin_addr
.s_addr
;
1131 __be32 mask
= ((struct sockaddr_in
*)&r
->arp_netmask
)->sin_addr
.s_addr
;
1133 if (mask
== htonl(0xFFFFFFFF))
1134 return pneigh_delete(&arp_tbl
, net
, &ip
, dev
);
1139 return arp_req_set_proxy(net
, dev
, 0);
1142 static int arp_req_delete(struct net
*net
, struct arpreq
*r
,
1143 struct net_device
* dev
)
1147 struct neighbour
*neigh
;
1149 if (r
->arp_flags
& ATF_PUBL
)
1150 return arp_req_delete_public(net
, r
, dev
);
1152 ip
= ((struct sockaddr_in
*)&r
->arp_pa
)->sin_addr
.s_addr
;
1154 struct flowi fl
= { .nl_u
= { .ip4_u
= { .daddr
= ip
,
1155 .tos
= RTO_ONLINK
} } };
1157 if ((err
= ip_route_output_key(net
, &rt
, &fl
)) != 0)
1165 neigh
= neigh_lookup(&arp_tbl
, &ip
, dev
);
1167 if (neigh
->nud_state
&~NUD_NOARP
)
1168 err
= neigh_update(neigh
, NULL
, NUD_FAILED
,
1169 NEIGH_UPDATE_F_OVERRIDE
|
1170 NEIGH_UPDATE_F_ADMIN
);
1171 neigh_release(neigh
);
1177 * Handle an ARP layer I/O control request.
1180 int arp_ioctl(struct net
*net
, unsigned int cmd
, void __user
*arg
)
1184 struct net_device
*dev
= NULL
;
1189 if (!capable(CAP_NET_ADMIN
))
1192 err
= copy_from_user(&r
, arg
, sizeof(struct arpreq
));
1200 if (r
.arp_pa
.sa_family
!= AF_INET
)
1201 return -EPFNOSUPPORT
;
1203 if (!(r
.arp_flags
& ATF_PUBL
) &&
1204 (r
.arp_flags
& (ATF_NETMASK
|ATF_DONTPUB
)))
1206 if (!(r
.arp_flags
& ATF_NETMASK
))
1207 ((struct sockaddr_in
*)&r
.arp_netmask
)->sin_addr
.s_addr
=
1208 htonl(0xFFFFFFFFUL
);
1212 if ((dev
= __dev_get_by_name(net
, r
.arp_dev
)) == NULL
)
1215 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1216 if (!r
.arp_ha
.sa_family
)
1217 r
.arp_ha
.sa_family
= dev
->type
;
1219 if ((r
.arp_flags
& ATF_COM
) && r
.arp_ha
.sa_family
!= dev
->type
)
1221 } else if (cmd
== SIOCGARP
) {
1228 err
= arp_req_delete(net
, &r
, dev
);
1231 err
= arp_req_set(net
, &r
, dev
);
1234 err
= arp_req_get(&r
, dev
);
1235 if (!err
&& copy_to_user(arg
, &r
, sizeof(r
)))
1244 static int arp_netdev_event(struct notifier_block
*this, unsigned long event
, void *ptr
)
1246 struct net_device
*dev
= ptr
;
1249 case NETDEV_CHANGEADDR
:
1250 neigh_changeaddr(&arp_tbl
, dev
);
1251 rt_cache_flush(dev_net(dev
), 0);
1260 static struct notifier_block arp_netdev_notifier
= {
1261 .notifier_call
= arp_netdev_event
,
1264 /* Note, that it is not on notifier chain.
1265 It is necessary, that this routine was called after route cache will be
1268 void arp_ifdown(struct net_device
*dev
)
1270 neigh_ifdown(&arp_tbl
, dev
);
1275 * Called once on startup.
1278 static struct packet_type arp_packet_type __read_mostly
= {
1279 .type
= cpu_to_be16(ETH_P_ARP
),
1283 static int arp_proc_init(void);
1285 void __init
arp_init(void)
1287 neigh_table_init(&arp_tbl
);
1289 dev_add_pack(&arp_packet_type
);
1291 #ifdef CONFIG_SYSCTL
1292 neigh_sysctl_register(NULL
, &arp_tbl
.parms
, "ipv4", NULL
);
1294 register_netdevice_notifier(&arp_netdev_notifier
);
1297 #ifdef CONFIG_PROC_FS
1298 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1300 /* ------------------------------------------------------------------------ */
1302 * ax25 -> ASCII conversion
1304 static char *ax2asc2(ax25_address
*a
, char *buf
)
1309 for (n
= 0, s
= buf
; n
< 6; n
++) {
1310 c
= (a
->ax25_call
[n
] >> 1) & 0x7F;
1312 if (c
!= ' ') *s
++ = c
;
1317 if ((n
= ((a
->ax25_call
[6] >> 1) & 0x0F)) > 9) {
1325 if (*buf
== '\0' || *buf
== '-')
1331 #endif /* CONFIG_AX25 */
1333 #define HBUFFERLEN 30
1335 static void arp_format_neigh_entry(struct seq_file
*seq
,
1336 struct neighbour
*n
)
1338 char hbuffer
[HBUFFERLEN
];
1341 struct net_device
*dev
= n
->dev
;
1342 int hatype
= dev
->type
;
1344 read_lock(&n
->lock
);
1345 /* Convert hardware address to XX:XX:XX:XX ... form. */
1346 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1347 if (hatype
== ARPHRD_AX25
|| hatype
== ARPHRD_NETROM
)
1348 ax2asc2((ax25_address
*)n
->ha
, hbuffer
);
1351 for (k
= 0, j
= 0; k
< HBUFFERLEN
- 3 && j
< dev
->addr_len
; j
++) {
1352 hbuffer
[k
++] = hex_asc_hi(n
->ha
[j
]);
1353 hbuffer
[k
++] = hex_asc_lo(n
->ha
[j
]);
1359 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1362 sprintf(tbuf
, "%pI4", n
->primary_key
);
1363 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1364 tbuf
, hatype
, arp_state_to_flags(n
), hbuffer
, dev
->name
);
1365 read_unlock(&n
->lock
);
1368 static void arp_format_pneigh_entry(struct seq_file
*seq
,
1369 struct pneigh_entry
*n
)
1371 struct net_device
*dev
= n
->dev
;
1372 int hatype
= dev
? dev
->type
: 0;
1375 sprintf(tbuf
, "%pI4", n
->key
);
1376 seq_printf(seq
, "%-16s 0x%-10x0x%-10x%s * %s\n",
1377 tbuf
, hatype
, ATF_PUBL
| ATF_PERM
, "00:00:00:00:00:00",
1378 dev
? dev
->name
: "*");
1381 static int arp_seq_show(struct seq_file
*seq
, void *v
)
1383 if (v
== SEQ_START_TOKEN
) {
1384 seq_puts(seq
, "IP address HW type Flags "
1385 "HW address Mask Device\n");
1387 struct neigh_seq_state
*state
= seq
->private;
1389 if (state
->flags
& NEIGH_SEQ_IS_PNEIGH
)
1390 arp_format_pneigh_entry(seq
, v
);
1392 arp_format_neigh_entry(seq
, v
);
1398 static void *arp_seq_start(struct seq_file
*seq
, loff_t
*pos
)
1400 /* Don't want to confuse "arp -a" w/ magic entries,
1401 * so we tell the generic iterator to skip NUD_NOARP.
1403 return neigh_seq_start(seq
, pos
, &arp_tbl
, NEIGH_SEQ_SKIP_NOARP
);
1406 /* ------------------------------------------------------------------------ */
1408 static const struct seq_operations arp_seq_ops
= {
1409 .start
= arp_seq_start
,
1410 .next
= neigh_seq_next
,
1411 .stop
= neigh_seq_stop
,
1412 .show
= arp_seq_show
,
1415 static int arp_seq_open(struct inode
*inode
, struct file
*file
)
1417 return seq_open_net(inode
, file
, &arp_seq_ops
,
1418 sizeof(struct neigh_seq_state
));
1421 static const struct file_operations arp_seq_fops
= {
1422 .owner
= THIS_MODULE
,
1423 .open
= arp_seq_open
,
1425 .llseek
= seq_lseek
,
1426 .release
= seq_release_net
,
1430 static int __net_init
arp_net_init(struct net
*net
)
1432 if (!proc_net_fops_create(net
, "arp", S_IRUGO
, &arp_seq_fops
))
1437 static void __net_exit
arp_net_exit(struct net
*net
)
1439 proc_net_remove(net
, "arp");
1442 static struct pernet_operations arp_net_ops
= {
1443 .init
= arp_net_init
,
1444 .exit
= arp_net_exit
,
1447 static int __init
arp_proc_init(void)
1449 return register_pernet_subsys(&arp_net_ops
);
1452 #else /* CONFIG_PROC_FS */
1454 static int __init
arp_proc_init(void)
1459 #endif /* CONFIG_PROC_FS */