~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/ipv4/arp.c

Version: ~ [ linux-6.1-rc7 ] ~ [ linux-6.0.10 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.80 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.156 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.225 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.267 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.300 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.334 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.302 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /* linux/net/ipv4/arp.c
  3  *
  4  * Copyright (C) 1994 by Florian  La Roche
  5  *
  6  * This module implements the Address Resolution Protocol ARP (RFC 826),
  7  * which is used to convert IP addresses (or in the future maybe other
  8  * high-level addresses) into a low-level hardware address (like an Ethernet
  9  * address).
 10  *
 11  * Fixes:
 12  *              Alan Cox        :       Removed the Ethernet assumptions in
 13  *                                      Florian's code
 14  *              Alan Cox        :       Fixed some small errors in the ARP
 15  *                                      logic
 16  *              Alan Cox        :       Allow >4K in /proc
 17  *              Alan Cox        :       Make ARP add its own protocol entry
 18  *              Ross Martin     :       Rewrote arp_rcv() and arp_get_info()
 19  *              Stephen Henson  :       Add AX25 support to arp_get_info()
 20  *              Alan Cox        :       Drop data when a device is downed.
 21  *              Alan Cox        :       Use init_timer().
 22  *              Alan Cox        :       Double lock fixes.
 23  *              Martin Seine    :       Move the arphdr structure
 24  *                                      to if_arp.h for compatibility.
 25  *                                      with BSD based programs.
 26  *              Andrew Tridgell :       Added ARP netmask code and
 27  *                                      re-arranged proxy handling.
 28  *              Alan Cox        :       Changed to use notifiers.
 29  *              Niibe Yutaka    :       Reply for this device or proxies only.
 30  *              Alan Cox        :       Don't proxy across hardware types!
 31  *              Jonathan Naylor :       Added support for NET/ROM.
 32  *              Mike Shaver     :       RFC1122 checks.
 33  *              Jonathan Naylor :       Only lookup the hardware address for
 34  *                                      the correct hardware type.
 35  *              Germano Caronni :       Assorted subtle races.
 36  *              Craig Schlenter :       Don't modify permanent entry
 37  *                                      during arp_rcv.
 38  *              Russ Nelson     :       Tidied up a few bits.
 39  *              Alexey Kuznetsov:       Major changes to caching and behaviour,
 40  *                                      eg intelligent arp probing and
 41  *                                      generation
 42  *                                      of host down events.
 43  *              Alan Cox        :       Missing unlock in device events.
 44  *              Eckes           :       ARP ioctl control errors.
 45  *              Alexey Kuznetsov:       Arp free fix.
 46  *              Manuel Rodriguez:       Gratuitous ARP.
 47  *              Jonathan Layes  :       Added arpd support through kerneld
 48  *                                      message queue (960314)
 49  *              Mike Shaver     :       /proc/sys/net/ipv4/arp_* support
 50  *              Mike McLagan    :       Routing by source
 51  *              Stuart Cheshire :       Metricom and grat arp fixes
 52  *                                      *** FOR 2.1 clean this up ***
 53  *              Lawrence V. Stefani: (08/12/96) Added FDDI support.
 54  *              Alan Cox        :       Took the AP1000 nasty FDDI hack and
 55  *                                      folded into the mainstream FDDI code.
 56  *                                      Ack spit, Linus how did you allow that
 57  *                                      one in...
 58  *              Jes Sorensen    :       Make FDDI work again in 2.1.x and
 59  *                                      clean up the APFDDI & gen. FDDI bits.
 60  *              Alexey Kuznetsov:       new arp state machine;
 61  *                                      now it is in net/core/neighbour.c.
 62  *              Krzysztof Halasa:       Added Frame Relay ARP support.
 63  *              Arnaldo C. Melo :       convert /proc/net/arp to seq_file
 64  *              Shmulik Hen:            Split arp_send to arp_create and
 65  *                                      arp_xmit so intermediate drivers like
 66  *                                      bonding can change the skb before
 67  *                                      sending (e.g. insert 8021q tag).
 68  *              Harald Welte    :       convert to make use of jenkins hash
 69  *              Jesper D. Brouer:       Proxy ARP PVLAN RFC 3069 support.
 70  */
 71 
 72 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 73 
 74 #include <linux/module.h>
 75 #include <linux/types.h>
 76 #include <linux/string.h>
 77 #include <linux/kernel.h>
 78 #include <linux/capability.h>
 79 #include <linux/socket.h>
 80 #include <linux/sockios.h>
 81 #include <linux/errno.h>
 82 #include <linux/in.h>
 83 #include <linux/mm.h>
 84 #include <linux/inet.h>
 85 #include <linux/inetdevice.h>
 86 #include <linux/netdevice.h>
 87 #include <linux/etherdevice.h>
 88 #include <linux/fddidevice.h>
 89 #include <linux/if_arp.h>
 90 #include <linux/skbuff.h>
 91 #include <linux/proc_fs.h>
 92 #include <linux/seq_file.h>
 93 #include <linux/stat.h>
 94 #include <linux/init.h>
 95 #include <linux/net.h>
 96 #include <linux/rcupdate.h>
 97 #include <linux/slab.h>
 98 #ifdef CONFIG_SYSCTL
 99 #include <linux/sysctl.h>
100 #endif
101 
102 #include <net/net_namespace.h>
103 #include <net/ip.h>
104 #include <net/icmp.h>
105 #include <net/route.h>
106 #include <net/protocol.h>
107 #include <net/tcp.h>
108 #include <net/sock.h>
109 #include <net/arp.h>
110 #include <net/ax25.h>
111 #include <net/netrom.h>
112 #include <net/dst_metadata.h>
113 #include <net/ip_tunnels.h>
114 
115 #include <linux/uaccess.h>
116 
117 #include <linux/netfilter_arp.h>
118 
119 /*
120  *      Interface to generic neighbour cache.
121  */
122 static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
123 static bool arp_key_eq(const struct neighbour *n, const void *pkey);
124 static int arp_constructor(struct neighbour *neigh);
125 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
126 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
127 static void parp_redo(struct sk_buff *skb);
128 static int arp_is_multicast(const void *pkey);
129 
130 static const struct neigh_ops arp_generic_ops = {
131         .family =               AF_INET,
132         .solicit =              arp_solicit,
133         .error_report =         arp_error_report,
134         .output =               neigh_resolve_output,
135         .connected_output =     neigh_connected_output,
136 };
137 
138 static const struct neigh_ops arp_hh_ops = {
139         .family =               AF_INET,
140         .solicit =              arp_solicit,
141         .error_report =         arp_error_report,
142         .output =               neigh_resolve_output,
143         .connected_output =     neigh_resolve_output,
144 };
145 
146 static const struct neigh_ops arp_direct_ops = {
147         .family =               AF_INET,
148         .output =               neigh_direct_output,
149         .connected_output =     neigh_direct_output,
150 };
151 
152 struct neigh_table arp_tbl = {
153         .family         = AF_INET,
154         .key_len        = 4,
155         .protocol       = cpu_to_be16(ETH_P_IP),
156         .hash           = arp_hash,
157         .key_eq         = arp_key_eq,
158         .constructor    = arp_constructor,
159         .proxy_redo     = parp_redo,
160         .is_multicast   = arp_is_multicast,
161         .id             = "arp_cache",
162         .parms          = {
163                 .tbl                    = &arp_tbl,
164                 .reachable_time         = 30 * HZ,
165                 .data   = {
166                         [NEIGH_VAR_MCAST_PROBES] = 3,
167                         [NEIGH_VAR_UCAST_PROBES] = 3,
168                         [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
169                         [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
170                         [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
171                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
172                         [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
173                         [NEIGH_VAR_PROXY_QLEN] = 64,
174                         [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
175                         [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
176                         [NEIGH_VAR_LOCKTIME] = 1 * HZ,
177                 },
178         },
179         .gc_interval    = 30 * HZ,
180         .gc_thresh1     = 128,
181         .gc_thresh2     = 512,
182         .gc_thresh3     = 1024,
183 };
184 EXPORT_SYMBOL(arp_tbl);
185 
186 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
187 {
188         switch (dev->type) {
189         case ARPHRD_ETHER:
190         case ARPHRD_FDDI:
191         case ARPHRD_IEEE802:
192                 ip_eth_mc_map(addr, haddr);
193                 return 0;
194         case ARPHRD_INFINIBAND:
195                 ip_ib_mc_map(addr, dev->broadcast, haddr);
196                 return 0;
197         case ARPHRD_IPGRE:
198                 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
199                 return 0;
200         default:
201                 if (dir) {
202                         memcpy(haddr, dev->broadcast, dev->addr_len);
203                         return 0;
204                 }
205         }
206         return -EINVAL;
207 }
208 
209 
210 static u32 arp_hash(const void *pkey,
211                     const struct net_device *dev,
212                     __u32 *hash_rnd)
213 {
214         return arp_hashfn(pkey, dev, hash_rnd);
215 }
216 
217 static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
218 {
219         return neigh_key_eq32(neigh, pkey);
220 }
221 
222 static int arp_constructor(struct neighbour *neigh)
223 {
224         __be32 addr;
225         struct net_device *dev = neigh->dev;
226         struct in_device *in_dev;
227         struct neigh_parms *parms;
228         u32 inaddr_any = INADDR_ANY;
229 
230         if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
231                 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len);
232 
233         addr = *(__be32 *)neigh->primary_key;
234         rcu_read_lock();
235         in_dev = __in_dev_get_rcu(dev);
236         if (!in_dev) {
237                 rcu_read_unlock();
238                 return -EINVAL;
239         }
240 
241         neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
242 
243         parms = in_dev->arp_parms;
244         __neigh_parms_put(neigh->parms);
245         neigh->parms = neigh_parms_clone(parms);
246         rcu_read_unlock();
247 
248         if (!dev->header_ops) {
249                 neigh->nud_state = NUD_NOARP;
250                 neigh->ops = &arp_direct_ops;
251                 neigh->output = neigh_direct_output;
252         } else {
253                 /* Good devices (checked by reading texts, but only Ethernet is
254                    tested)
255 
256                    ARPHRD_ETHER: (ethernet, apfddi)
257                    ARPHRD_FDDI: (fddi)
258                    ARPHRD_IEEE802: (tr)
259                    ARPHRD_METRICOM: (strip)
260                    ARPHRD_ARCNET:
261                    etc. etc. etc.
262 
263                    ARPHRD_IPDDP will also work, if author repairs it.
264                    I did not it, because this driver does not work even
265                    in old paradigm.
266                  */
267 
268                 if (neigh->type == RTN_MULTICAST) {
269                         neigh->nud_state = NUD_NOARP;
270                         arp_mc_map(addr, neigh->ha, dev, 1);
271                 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
272                         neigh->nud_state = NUD_NOARP;
273                         memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
274                 } else if (neigh->type == RTN_BROADCAST ||
275                            (dev->flags & IFF_POINTOPOINT)) {
276                         neigh->nud_state = NUD_NOARP;
277                         memcpy(neigh->ha, dev->broadcast, dev->addr_len);
278                 }
279 
280                 if (dev->header_ops->cache)
281                         neigh->ops = &arp_hh_ops;
282                 else
283                         neigh->ops = &arp_generic_ops;
284 
285                 if (neigh->nud_state & NUD_VALID)
286                         neigh->output = neigh->ops->connected_output;
287                 else
288                         neigh->output = neigh->ops->output;
289         }
290         return 0;
291 }
292 
293 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
294 {
295         dst_link_failure(skb);
296         kfree_skb(skb);
297 }
298 
299 /* Create and send an arp packet. */
300 static void arp_send_dst(int type, int ptype, __be32 dest_ip,
301                          struct net_device *dev, __be32 src_ip,
302                          const unsigned char *dest_hw,
303                          const unsigned char *src_hw,
304                          const unsigned char *target_hw,
305                          struct dst_entry *dst)
306 {
307         struct sk_buff *skb;
308 
309         /* arp on this interface. */
310         if (dev->flags & IFF_NOARP)
311                 return;
312 
313         skb = arp_create(type, ptype, dest_ip, dev, src_ip,
314                          dest_hw, src_hw, target_hw);
315         if (!skb)
316                 return;
317 
318         skb_dst_set(skb, dst_clone(dst));
319         arp_xmit(skb);
320 }
321 
322 void arp_send(int type, int ptype, __be32 dest_ip,
323               struct net_device *dev, __be32 src_ip,
324               const unsigned char *dest_hw, const unsigned char *src_hw,
325               const unsigned char *target_hw)
326 {
327         arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
328                      target_hw, NULL);
329 }
330 EXPORT_SYMBOL(arp_send);
331 
332 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
333 {
334         __be32 saddr = 0;
335         u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
336         struct net_device *dev = neigh->dev;
337         __be32 target = *(__be32 *)neigh->primary_key;
338         int probes = atomic_read(&neigh->probes);
339         struct in_device *in_dev;
340         struct dst_entry *dst = NULL;
341 
342         rcu_read_lock();
343         in_dev = __in_dev_get_rcu(dev);
344         if (!in_dev) {
345                 rcu_read_unlock();
346                 return;
347         }
348         switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
349         default:
350         case 0:         /* By default announce any local IP */
351                 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
352                                           ip_hdr(skb)->saddr) == RTN_LOCAL)
353                         saddr = ip_hdr(skb)->saddr;
354                 break;
355         case 1:         /* Restrict announcements of saddr in same subnet */
356                 if (!skb)
357                         break;
358                 saddr = ip_hdr(skb)->saddr;
359                 if (inet_addr_type_dev_table(dev_net(dev), dev,
360                                              saddr) == RTN_LOCAL) {
361                         /* saddr should be known to target */
362                         if (inet_addr_onlink(in_dev, target, saddr))
363                                 break;
364                 }
365                 saddr = 0;
366                 break;
367         case 2:         /* Avoid secondary IPs, get a primary/preferred one */
368                 break;
369         }
370         rcu_read_unlock();
371 
372         if (!saddr)
373                 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
374 
375         probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
376         if (probes < 0) {
377                 if (!(neigh->nud_state & NUD_VALID))
378                         pr_debug("trying to ucast probe in NUD_INVALID\n");
379                 neigh_ha_snapshot(dst_ha, neigh, dev);
380                 dst_hw = dst_ha;
381         } else {
382                 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
383                 if (probes < 0) {
384                         neigh_app_ns(neigh);
385                         return;
386                 }
387         }
388 
389         if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
390                 dst = skb_dst(skb);
391         arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
392                      dst_hw, dev->dev_addr, NULL, dst);
393 }
394 
395 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
396 {
397         struct net *net = dev_net(in_dev->dev);
398         int scope;
399 
400         switch (IN_DEV_ARP_IGNORE(in_dev)) {
401         case 0: /* Reply, the tip is already validated */
402                 return 0;
403         case 1: /* Reply only if tip is configured on the incoming interface */
404                 sip = 0;
405                 scope = RT_SCOPE_HOST;
406                 break;
407         case 2: /*
408                  * Reply only if tip is configured on the incoming interface
409                  * and is in same subnet as sip
410                  */
411                 scope = RT_SCOPE_HOST;
412                 break;
413         case 3: /* Do not reply for scope host addresses */
414                 sip = 0;
415                 scope = RT_SCOPE_LINK;
416                 in_dev = NULL;
417                 break;
418         case 4: /* Reserved */
419         case 5:
420         case 6:
421         case 7:
422                 return 0;
423         case 8: /* Do not reply */
424                 return 1;
425         default:
426                 return 0;
427         }
428         return !inet_confirm_addr(net, in_dev, sip, tip, scope);
429 }
430 
431 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
432 {
433         struct rtable *rt;
434         int flag = 0;
435         /*unsigned long now; */
436         struct net *net = dev_net(dev);
437 
438         rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev));
439         if (IS_ERR(rt))
440                 return 1;
441         if (rt->dst.dev != dev) {
442                 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER);
443                 flag = 1;
444         }
445         ip_rt_put(rt);
446         return flag;
447 }
448 
449 /*
450  * Check if we can use proxy ARP for this path
451  */
452 static inline int arp_fwd_proxy(struct in_device *in_dev,
453                                 struct net_device *dev, struct rtable *rt)
454 {
455         struct in_device *out_dev;
456         int imi, omi = -1;
457 
458         if (rt->dst.dev == dev)
459                 return 0;
460 
461         if (!IN_DEV_PROXY_ARP(in_dev))
462                 return 0;
463         imi = IN_DEV_MEDIUM_ID(in_dev);
464         if (imi == 0)
465                 return 1;
466         if (imi == -1)
467                 return 0;
468 
469         /* place to check for proxy_arp for routes */
470 
471         out_dev = __in_dev_get_rcu(rt->dst.dev);
472         if (out_dev)
473                 omi = IN_DEV_MEDIUM_ID(out_dev);
474 
475         return omi != imi && omi != -1;
476 }
477 
478 /*
479  * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
480  *
481  * RFC3069 supports proxy arp replies back to the same interface.  This
482  * is done to support (ethernet) switch features, like RFC 3069, where
483  * the individual ports are not allowed to communicate with each
484  * other, BUT they are allowed to talk to the upstream router.  As
485  * described in RFC 3069, it is possible to allow these hosts to
486  * communicate through the upstream router, by proxy_arp'ing.
487  *
488  * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
489  *
490  *  This technology is known by different names:
491  *    In RFC 3069 it is called VLAN Aggregation.
492  *    Cisco and Allied Telesyn call it Private VLAN.
493  *    Hewlett-Packard call it Source-Port filtering or port-isolation.
494  *    Ericsson call it MAC-Forced Forwarding (RFC Draft).
495  *
496  */
497 static inline int arp_fwd_pvlan(struct in_device *in_dev,
498                                 struct net_device *dev, struct rtable *rt,
499                                 __be32 sip, __be32 tip)
500 {
501         /* Private VLAN is only concerned about the same ethernet segment */
502         if (rt->dst.dev != dev)
503                 return 0;
504 
505         /* Don't reply on self probes (often done by windowz boxes)*/
506         if (sip == tip)
507                 return 0;
508 
509         if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
510                 return 1;
511         else
512                 return 0;
513 }
514 
515 /*
516  *      Interface to link layer: send routine and receive handler.
517  */
518 
519 /*
520  *      Create an arp packet. If dest_hw is not set, we create a broadcast
521  *      message.
522  */
523 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
524                            struct net_device *dev, __be32 src_ip,
525                            const unsigned char *dest_hw,
526                            const unsigned char *src_hw,
527                            const unsigned char *target_hw)
528 {
529         struct sk_buff *skb;
530         struct arphdr *arp;
531         unsigned char *arp_ptr;
532         int hlen = LL_RESERVED_SPACE(dev);
533         int tlen = dev->needed_tailroom;
534 
535         /*
536          *      Allocate a buffer
537          */
538 
539         skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
540         if (!skb)
541                 return NULL;
542 
543         skb_reserve(skb, hlen);
544         skb_reset_network_header(skb);
545         arp = skb_put(skb, arp_hdr_len(dev));
546         skb->dev = dev;
547         skb->protocol = htons(ETH_P_ARP);
548         if (!src_hw)
549                 src_hw = dev->dev_addr;
550         if (!dest_hw)
551                 dest_hw = dev->broadcast;
552 
553         /*
554          *      Fill the device header for the ARP frame
555          */
556         if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
557                 goto out;
558 
559         /*
560          * Fill out the arp protocol part.
561          *
562          * The arp hardware type should match the device type, except for FDDI,
563          * which (according to RFC 1390) should always equal 1 (Ethernet).
564          */
565         /*
566          *      Exceptions everywhere. AX.25 uses the AX.25 PID value not the
567          *      DIX code for the protocol. Make these device structure fields.
568          */
569         switch (dev->type) {
570         default:
571                 arp->ar_hrd = htons(dev->type);
572                 arp->ar_pro = htons(ETH_P_IP);
573                 break;
574 
575 #if IS_ENABLED(CONFIG_AX25)
576         case ARPHRD_AX25:
577                 arp->ar_hrd = htons(ARPHRD_AX25);
578                 arp->ar_pro = htons(AX25_P_IP);
579                 break;
580 
581 #if IS_ENABLED(CONFIG_NETROM)
582         case ARPHRD_NETROM:
583                 arp->ar_hrd = htons(ARPHRD_NETROM);
584                 arp->ar_pro = htons(AX25_P_IP);
585                 break;
586 #endif
587 #endif
588 
589 #if IS_ENABLED(CONFIG_FDDI)
590         case ARPHRD_FDDI:
591                 arp->ar_hrd = htons(ARPHRD_ETHER);
592                 arp->ar_pro = htons(ETH_P_IP);
593                 break;
594 #endif
595         }
596 
597         arp->ar_hln = dev->addr_len;
598         arp->ar_pln = 4;
599         arp->ar_op = htons(type);
600 
601         arp_ptr = (unsigned char *)(arp + 1);
602 
603         memcpy(arp_ptr, src_hw, dev->addr_len);
604         arp_ptr += dev->addr_len;
605         memcpy(arp_ptr, &src_ip, 4);
606         arp_ptr += 4;
607 
608         switch (dev->type) {
609 #if IS_ENABLED(CONFIG_FIREWIRE_NET)
610         case ARPHRD_IEEE1394:
611                 break;
612 #endif
613         default:
614                 if (target_hw)
615                         memcpy(arp_ptr, target_hw, dev->addr_len);
616                 else
617                         memset(arp_ptr, 0, dev->addr_len);
618                 arp_ptr += dev->addr_len;
619         }
620         memcpy(arp_ptr, &dest_ip, 4);
621 
622         return skb;
623 
624 out:
625         kfree_skb(skb);
626         return NULL;
627 }
628 EXPORT_SYMBOL(arp_create);
629 
630 static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
631 {
632         return dev_queue_xmit(skb);
633 }
634 
635 /*
636  *      Send an arp packet.
637  */
638 void arp_xmit(struct sk_buff *skb)
639 {
640         /* Send it off, maybe filter it using firewalling first.  */
641         NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
642                 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
643                 arp_xmit_finish);
644 }
645 EXPORT_SYMBOL(arp_xmit);
646 
647 static bool arp_is_garp(struct net *net, struct net_device *dev,
648                         int *addr_type, __be16 ar_op,
649                         __be32 sip, __be32 tip,
650                         unsigned char *sha, unsigned char *tha)
651 {
652         bool is_garp = tip == sip;
653 
654         /* Gratuitous ARP _replies_ also require target hwaddr to be
655          * the same as source.
656          */
657         if (is_garp && ar_op == htons(ARPOP_REPLY))
658                 is_garp =
659                         /* IPv4 over IEEE 1394 doesn't provide target
660                          * hardware address field in its ARP payload.
661                          */
662                         tha &&
663                         !memcmp(tha, sha, dev->addr_len);
664 
665         if (is_garp) {
666                 *addr_type = inet_addr_type_dev_table(net, dev, sip);
667                 if (*addr_type != RTN_UNICAST)
668                         is_garp = false;
669         }
670         return is_garp;
671 }
672 
673 /*
674  *      Process an arp request.
675  */
676 
677 static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
678 {
679         struct net_device *dev = skb->dev;
680         struct in_device *in_dev = __in_dev_get_rcu(dev);
681         struct arphdr *arp;
682         unsigned char *arp_ptr;
683         struct rtable *rt;
684         unsigned char *sha;
685         unsigned char *tha = NULL;
686         __be32 sip, tip;
687         u16 dev_type = dev->type;
688         int addr_type;
689         struct neighbour *n;
690         struct dst_entry *reply_dst = NULL;
691         bool is_garp = false;
692 
693         /* arp_rcv below verifies the ARP header and verifies the device
694          * is ARP'able.
695          */
696 
697         if (!in_dev)
698                 goto out_free_skb;
699 
700         arp = arp_hdr(skb);
701 
702         switch (dev_type) {
703         default:
704                 if (arp->ar_pro != htons(ETH_P_IP) ||
705                     htons(dev_type) != arp->ar_hrd)
706                         goto out_free_skb;
707                 break;
708         case ARPHRD_ETHER:
709         case ARPHRD_FDDI:
710         case ARPHRD_IEEE802:
711                 /*
712                  * ETHERNET, and Fibre Channel (which are IEEE 802
713                  * devices, according to RFC 2625) devices will accept ARP
714                  * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
715                  * This is the case also of FDDI, where the RFC 1390 says that
716                  * FDDI devices should accept ARP hardware of (1) Ethernet,
717                  * however, to be more robust, we'll accept both 1 (Ethernet)
718                  * or 6 (IEEE 802.2)
719                  */
720                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
721                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
722                     arp->ar_pro != htons(ETH_P_IP))
723                         goto out_free_skb;
724                 break;
725         case ARPHRD_AX25:
726                 if (arp->ar_pro != htons(AX25_P_IP) ||
727                     arp->ar_hrd != htons(ARPHRD_AX25))
728                         goto out_free_skb;
729                 break;
730         case ARPHRD_NETROM:
731                 if (arp->ar_pro != htons(AX25_P_IP) ||
732                     arp->ar_hrd != htons(ARPHRD_NETROM))
733                         goto out_free_skb;
734                 break;
735         }
736 
737         /* Understand only these message types */
738 
739         if (arp->ar_op != htons(ARPOP_REPLY) &&
740             arp->ar_op != htons(ARPOP_REQUEST))
741                 goto out_free_skb;
742 
743 /*
744  *      Extract fields
745  */
746         arp_ptr = (unsigned char *)(arp + 1);
747         sha     = arp_ptr;
748         arp_ptr += dev->addr_len;
749         memcpy(&sip, arp_ptr, 4);
750         arp_ptr += 4;
751         switch (dev_type) {
752 #if IS_ENABLED(CONFIG_FIREWIRE_NET)
753         case ARPHRD_IEEE1394:
754                 break;
755 #endif
756         default:
757                 tha = arp_ptr;
758                 arp_ptr += dev->addr_len;
759         }
760         memcpy(&tip, arp_ptr, 4);
761 /*
762  *      Check for bad requests for 127.x.x.x and requests for multicast
763  *      addresses.  If this is one such, delete it.
764  */
765         if (ipv4_is_multicast(tip) ||
766             (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
767                 goto out_free_skb;
768 
769  /*
770   *     For some 802.11 wireless deployments (and possibly other networks),
771   *     there will be an ARP proxy and gratuitous ARP frames are attacks
772   *     and thus should not be accepted.
773   */
774         if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
775                 goto out_free_skb;
776 
777 /*
778  *     Special case: We must set Frame Relay source Q.922 address
779  */
780         if (dev_type == ARPHRD_DLCI)
781                 sha = dev->broadcast;
782 
783 /*
784  *  Process entry.  The idea here is we want to send a reply if it is a
785  *  request for us or if it is a request for someone else that we hold
786  *  a proxy for.  We want to add an entry to our cache if it is a reply
787  *  to us or if it is a request for our address.
788  *  (The assumption for this last is that if someone is requesting our
789  *  address, they are probably intending to talk to us, so it saves time
790  *  if we cache their address.  Their address is also probably not in
791  *  our cache, since ours is not in their cache.)
792  *
793  *  Putting this another way, we only care about replies if they are to
794  *  us, in which case we add them to the cache.  For requests, we care
795  *  about those for us and those for our proxies.  We reply to both,
796  *  and in the case of requests for us we add the requester to the arp
797  *  cache.
798  */
799 
800         if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
801                 reply_dst = (struct dst_entry *)
802                             iptunnel_metadata_reply(skb_metadata_dst(skb),
803                                                     GFP_ATOMIC);
804 
805         /* Special case: IPv4 duplicate address detection packet (RFC2131) */
806         if (sip == 0) {
807                 if (arp->ar_op == htons(ARPOP_REQUEST) &&
808                     inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
809                     !arp_ignore(in_dev, sip, tip))
810                         arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
811                                      sha, dev->dev_addr, sha, reply_dst);
812                 goto out_consume_skb;
813         }
814 
815         if (arp->ar_op == htons(ARPOP_REQUEST) &&
816             ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
817 
818                 rt = skb_rtable(skb);
819                 addr_type = rt->rt_type;
820 
821                 if (addr_type == RTN_LOCAL) {
822                         int dont_send;
823 
824                         dont_send = arp_ignore(in_dev, sip, tip);
825                         if (!dont_send && IN_DEV_ARPFILTER(in_dev))
826                                 dont_send = arp_filter(sip, tip, dev);
827                         if (!dont_send) {
828                                 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
829                                 if (n) {
830                                         arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
831                                                      sip, dev, tip, sha,
832                                                      dev->dev_addr, sha,
833                                                      reply_dst);
834                                         neigh_release(n);
835                                 }
836                         }
837                         goto out_consume_skb;
838                 } else if (IN_DEV_FORWARD(in_dev)) {
839                         if (addr_type == RTN_UNICAST  &&
840                             (arp_fwd_proxy(in_dev, dev, rt) ||
841                              arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
842                              (rt->dst.dev != dev &&
843                               pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
844                                 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
845                                 if (n)
846                                         neigh_release(n);
847 
848                                 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
849                                     skb->pkt_type == PACKET_HOST ||
850                                     NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
851                                         arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
852                                                      sip, dev, tip, sha,
853                                                      dev->dev_addr, sha,
854                                                      reply_dst);
855                                 } else {
856                                         pneigh_enqueue(&arp_tbl,
857                                                        in_dev->arp_parms, skb);
858                                         goto out_free_dst;
859                                 }
860                                 goto out_consume_skb;
861                         }
862                 }
863         }
864 
865         /* Update our ARP tables */
866 
867         n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
868 
869         addr_type = -1;
870         if (n || IN_DEV_ARP_ACCEPT(in_dev)) {
871                 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
872                                       sip, tip, sha, tha);
873         }
874 
875         if (IN_DEV_ARP_ACCEPT(in_dev)) {
876                 /* Unsolicited ARP is not accepted by default.
877                    It is possible, that this option should be enabled for some
878                    devices (strip is candidate)
879                  */
880                 if (!n &&
881                     (is_garp ||
882                      (arp->ar_op == htons(ARPOP_REPLY) &&
883                       (addr_type == RTN_UNICAST ||
884                        (addr_type < 0 &&
885                         /* postpone calculation to as late as possible */
886                         inet_addr_type_dev_table(net, dev, sip) ==
887                                 RTN_UNICAST)))))
888                         n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
889         }
890 
891         if (n) {
892                 int state = NUD_REACHABLE;
893                 int override;
894 
895                 /* If several different ARP replies follows back-to-back,
896                    use the FIRST one. It is possible, if several proxy
897                    agents are active. Taking the first reply prevents
898                    arp trashing and chooses the fastest router.
899                  */
900                 override = time_after(jiffies,
901                                       n->updated +
902                                       NEIGH_VAR(n->parms, LOCKTIME)) ||
903                            is_garp;
904 
905                 /* Broadcast replies and request packets
906                    do not assert neighbour reachability.
907                  */
908                 if (arp->ar_op != htons(ARPOP_REPLY) ||
909                     skb->pkt_type != PACKET_HOST)
910                         state = NUD_STALE;
911                 neigh_update(n, sha, state,
912                              override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
913                 neigh_release(n);
914         }
915 
916 out_consume_skb:
917         consume_skb(skb);
918 
919 out_free_dst:
920         dst_release(reply_dst);
921         return NET_RX_SUCCESS;
922 
923 out_free_skb:
924         kfree_skb(skb);
925         return NET_RX_DROP;
926 }
927 
928 static void parp_redo(struct sk_buff *skb)
929 {
930         arp_process(dev_net(skb->dev), NULL, skb);
931 }
932 
933 static int arp_is_multicast(const void *pkey)
934 {
935         return ipv4_is_multicast(*((__be32 *)pkey));
936 }
937 
938 /*
939  *      Receive an arp request from the device layer.
940  */
941 
942 static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
943                    struct packet_type *pt, struct net_device *orig_dev)
944 {
945         const struct arphdr *arp;
946 
947         /* do not tweak dropwatch on an ARP we will ignore */
948         if (dev->flags & IFF_NOARP ||
949             skb->pkt_type == PACKET_OTHERHOST ||
950             skb->pkt_type == PACKET_LOOPBACK)
951                 goto consumeskb;
952 
953         skb = skb_share_check(skb, GFP_ATOMIC);
954         if (!skb)
955                 goto out_of_mem;
956 
957         /* ARP header, plus 2 device addresses, plus 2 IP addresses.  */
958         if (!pskb_may_pull(skb, arp_hdr_len(dev)))
959                 goto freeskb;
960 
961         arp = arp_hdr(skb);
962         if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
963                 goto freeskb;
964 
965         memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
966 
967         return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
968                        dev_net(dev), NULL, skb, dev, NULL,
969                        arp_process);
970 
971 consumeskb:
972         consume_skb(skb);
973         return NET_RX_SUCCESS;
974 freeskb:
975         kfree_skb(skb);
976 out_of_mem:
977         return NET_RX_DROP;
978 }
979 
980 /*
981  *      User level interface (ioctl)
982  */
983 
984 /*
985  *      Set (create) an ARP cache entry.
986  */
987 
988 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
989 {
990         if (!dev) {
991                 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
992                 return 0;
993         }
994         if (__in_dev_get_rtnl(dev)) {
995                 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
996                 return 0;
997         }
998         return -ENXIO;
999 }
1000 
1001 static int arp_req_set_public(struct net *net, struct arpreq *r,
1002                 struct net_device *dev)
1003 {
1004         __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1005         __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1006 
1007         if (mask && mask != htonl(0xFFFFFFFF))
1008                 return -EINVAL;
1009         if (!dev && (r->arp_flags & ATF_COM)) {
1010                 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1011                                       r->arp_ha.sa_data);
1012                 if (!dev)
1013                         return -ENODEV;
1014         }
1015         if (mask) {
1016                 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
1017                         return -ENOBUFS;
1018                 return 0;
1019         }
1020 
1021         return arp_req_set_proxy(net, dev, 1);
1022 }
1023 
1024 static int arp_req_set(struct net *net, struct arpreq *r,
1025                        struct net_device *dev)
1026 {
1027         __be32 ip;
1028         struct neighbour *neigh;
1029         int err;
1030 
1031         if (r->arp_flags & ATF_PUBL)
1032                 return arp_req_set_public(net, r, dev);
1033 
1034         ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1035         if (r->arp_flags & ATF_PERM)
1036                 r->arp_flags |= ATF_COM;
1037         if (!dev) {
1038                 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1039 
1040                 if (IS_ERR(rt))
1041                         return PTR_ERR(rt);
1042                 dev = rt->dst.dev;
1043                 ip_rt_put(rt);
1044                 if (!dev)
1045                         return -EINVAL;
1046         }
1047         switch (dev->type) {
1048 #if IS_ENABLED(CONFIG_FDDI)
1049         case ARPHRD_FDDI:
1050                 /*
1051                  * According to RFC 1390, FDDI devices should accept ARP
1052                  * hardware types of 1 (Ethernet).  However, to be more
1053                  * robust, we'll accept hardware types of either 1 (Ethernet)
1054                  * or 6 (IEEE 802.2).
1055                  */
1056                 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1057                     r->arp_ha.sa_family != ARPHRD_ETHER &&
1058                     r->arp_ha.sa_family != ARPHRD_IEEE802)
1059                         return -EINVAL;
1060                 break;
1061 #endif
1062         default:
1063                 if (r->arp_ha.sa_family != dev->type)
1064                         return -EINVAL;
1065                 break;
1066         }
1067 
1068         neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1069         err = PTR_ERR(neigh);
1070         if (!IS_ERR(neigh)) {
1071                 unsigned int state = NUD_STALE;
1072                 if (r->arp_flags & ATF_PERM)
1073                         state = NUD_PERMANENT;
1074                 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1075                                    r->arp_ha.sa_data : NULL, state,
1076                                    NEIGH_UPDATE_F_OVERRIDE |
1077                                    NEIGH_UPDATE_F_ADMIN, 0);
1078                 neigh_release(neigh);
1079         }
1080         return err;
1081 }
1082 
1083 static unsigned int arp_state_to_flags(struct neighbour *neigh)
1084 {
1085         if (neigh->nud_state&NUD_PERMANENT)
1086                 return ATF_PERM | ATF_COM;
1087         else if (neigh->nud_state&NUD_VALID)
1088                 return ATF_COM;
1089         else
1090                 return 0;
1091 }
1092 
1093 /*
1094  *      Get an ARP cache entry.
1095  */
1096 
1097 static int arp_req_get(struct arpreq *r, struct net_device *dev)
1098 {
1099         __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1100         struct neighbour *neigh;
1101         int err = -ENXIO;
1102 
1103         neigh = neigh_lookup(&arp_tbl, &ip, dev);
1104         if (neigh) {
1105                 if (!(neigh->nud_state & NUD_NOARP)) {
1106                         read_lock_bh(&neigh->lock);
1107                         memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1108                         r->arp_flags = arp_state_to_flags(neigh);
1109                         read_unlock_bh(&neigh->lock);
1110                         r->arp_ha.sa_family = dev->type;
1111                         strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1112                         err = 0;
1113                 }
1114                 neigh_release(neigh);
1115         }
1116         return err;
1117 }
1118 
1119 static int arp_invalidate(struct net_device *dev, __be32 ip)
1120 {
1121         struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1122         int err = -ENXIO;
1123         struct neigh_table *tbl = &arp_tbl;
1124 
1125         if (neigh) {
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, 0);
1130                 write_lock_bh(&tbl->lock);
1131                 neigh_release(neigh);
1132                 neigh_remove_one(neigh, tbl);
1133                 write_unlock_bh(&tbl->lock);
1134         }
1135 
1136         return err;
1137 }
1138 
1139 static int arp_req_delete_public(struct net *net, struct arpreq *r,
1140                 struct net_device *dev)
1141 {
1142         __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1143         __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1144 
1145         if (mask == htonl(0xFFFFFFFF))
1146                 return pneigh_delete(&arp_tbl, net, &ip, dev);
1147 
1148         if (mask)
1149                 return -EINVAL;
1150 
1151         return arp_req_set_proxy(net, dev, 0);
1152 }
1153 
1154 static int arp_req_delete(struct net *net, struct arpreq *r,
1155                           struct net_device *dev)
1156 {
1157         __be32 ip;
1158 
1159         if (r->arp_flags & ATF_PUBL)
1160                 return arp_req_delete_public(net, r, dev);
1161 
1162         ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1163         if (!dev) {
1164                 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1165                 if (IS_ERR(rt))
1166                         return PTR_ERR(rt);
1167                 dev = rt->dst.dev;
1168                 ip_rt_put(rt);
1169                 if (!dev)
1170                         return -EINVAL;
1171         }
1172         return arp_invalidate(dev, ip);
1173 }
1174 
1175 /*
1176  *      Handle an ARP layer I/O control request.
1177  */
1178 
1179 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1180 {
1181         int err;
1182         struct arpreq r;
1183         struct net_device *dev = NULL;
1184 
1185         switch (cmd) {
1186         case SIOCDARP:
1187         case SIOCSARP:
1188                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1189                         return -EPERM;
1190                 fallthrough;
1191         case SIOCGARP:
1192                 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1193                 if (err)
1194                         return -EFAULT;
1195                 break;
1196         default:
1197                 return -EINVAL;
1198         }
1199 
1200         if (r.arp_pa.sa_family != AF_INET)
1201                 return -EPFNOSUPPORT;
1202 
1203         if (!(r.arp_flags & ATF_PUBL) &&
1204             (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1205                 return -EINVAL;
1206         if (!(r.arp_flags & ATF_NETMASK))
1207                 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1208                                                            htonl(0xFFFFFFFFUL);
1209         rtnl_lock();
1210         if (r.arp_dev[0]) {
1211                 err = -ENODEV;
1212                 dev = __dev_get_by_name(net, r.arp_dev);
1213                 if (!dev)
1214                         goto out;
1215 
1216                 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1217                 if (!r.arp_ha.sa_family)
1218                         r.arp_ha.sa_family = dev->type;
1219                 err = -EINVAL;
1220                 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1221                         goto out;
1222         } else if (cmd == SIOCGARP) {
1223                 err = -ENODEV;
1224                 goto out;
1225         }
1226 
1227         switch (cmd) {
1228         case SIOCDARP:
1229                 err = arp_req_delete(net, &r, dev);
1230                 break;
1231         case SIOCSARP:
1232                 err = arp_req_set(net, &r, dev);
1233                 break;
1234         case SIOCGARP:
1235                 err = arp_req_get(&r, dev);
1236                 break;
1237         }
1238 out:
1239         rtnl_unlock();
1240         if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1241                 err = -EFAULT;
1242         return err;
1243 }
1244 
1245 static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1246                             void *ptr)
1247 {
1248         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1249         struct netdev_notifier_change_info *change_info;
1250 
1251         switch (event) {
1252         case NETDEV_CHANGEADDR:
1253                 neigh_changeaddr(&arp_tbl, dev);
1254                 rt_cache_flush(dev_net(dev));
1255                 break;
1256         case NETDEV_CHANGE:
1257                 change_info = ptr;
1258                 if (change_info->flags_changed & IFF_NOARP)
1259                         neigh_changeaddr(&arp_tbl, dev);
1260                 if (!netif_carrier_ok(dev))
1261                         neigh_carrier_down(&arp_tbl, dev);
1262                 break;
1263         default:
1264                 break;
1265         }
1266 
1267         return NOTIFY_DONE;
1268 }
1269 
1270 static struct notifier_block arp_netdev_notifier = {
1271         .notifier_call = arp_netdev_event,
1272 };
1273 
1274 /* Note, that it is not on notifier chain.
1275    It is necessary, that this routine was called after route cache will be
1276    flushed.
1277  */
1278 void arp_ifdown(struct net_device *dev)
1279 {
1280         neigh_ifdown(&arp_tbl, dev);
1281 }
1282 
1283 
1284 /*
1285  *      Called once on startup.
1286  */
1287 
1288 static struct packet_type arp_packet_type __read_mostly = {
1289         .type = cpu_to_be16(ETH_P_ARP),
1290         .func = arp_rcv,
1291 };
1292 
1293 static int arp_proc_init(void);
1294 
1295 void __init arp_init(void)
1296 {
1297         neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1298 
1299         dev_add_pack(&arp_packet_type);
1300         arp_proc_init();
1301 #ifdef CONFIG_SYSCTL
1302         neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1303 #endif
1304         register_netdevice_notifier(&arp_netdev_notifier);
1305 }
1306 
1307 #ifdef CONFIG_PROC_FS
1308 #if IS_ENABLED(CONFIG_AX25)
1309 
1310 /* ------------------------------------------------------------------------ */
1311 /*
1312  *      ax25 -> ASCII conversion
1313  */
1314 static void ax2asc2(ax25_address *a, char *buf)
1315 {
1316         char c, *s;
1317         int n;
1318 
1319         for (n = 0, s = buf; n < 6; n++) {
1320                 c = (a->ax25_call[n] >> 1) & 0x7F;
1321 
1322                 if (c != ' ')
1323                         *s++ = c;
1324         }
1325 
1326         *s++ = '-';
1327         n = (a->ax25_call[6] >> 1) & 0x0F;
1328         if (n > 9) {
1329                 *s++ = '1';
1330                 n -= 10;
1331         }
1332 
1333         *s++ = n + '';
1334         *s++ = '\0';
1335 
1336         if (*buf == '\0' || *buf == '-') {
1337                 buf[0] = '*';
1338                 buf[1] = '\0';
1339         }
1340 }
1341 #endif /* CONFIG_AX25 */
1342 
1343 #define HBUFFERLEN 30
1344 
1345 static void arp_format_neigh_entry(struct seq_file *seq,
1346                                    struct neighbour *n)
1347 {
1348         char hbuffer[HBUFFERLEN];
1349         int k, j;
1350         char tbuf[16];
1351         struct net_device *dev = n->dev;
1352         int hatype = dev->type;
1353 
1354         read_lock(&n->lock);
1355         /* Convert hardware address to XX:XX:XX:XX ... form. */
1356 #if IS_ENABLED(CONFIG_AX25)
1357         if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1358                 ax2asc2((ax25_address *)n->ha, hbuffer);
1359         else {
1360 #endif
1361         for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1362                 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1363                 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1364                 hbuffer[k++] = ':';
1365         }
1366         if (k != 0)
1367                 --k;
1368         hbuffer[k] = 0;
1369 #if IS_ENABLED(CONFIG_AX25)
1370         }
1371 #endif
1372         sprintf(tbuf, "%pI4", n->primary_key);
1373         seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s     *        %s\n",
1374                    tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1375         read_unlock(&n->lock);
1376 }
1377 
1378 static void arp_format_pneigh_entry(struct seq_file *seq,
1379                                     struct pneigh_entry *n)
1380 {
1381         struct net_device *dev = n->dev;
1382         int hatype = dev ? dev->type : 0;
1383         char tbuf[16];
1384 
1385         sprintf(tbuf, "%pI4", n->key);
1386         seq_printf(seq, "%-16s 0x%-10x0x%-10x%s     *        %s\n",
1387                    tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1388                    dev ? dev->name : "*");
1389 }
1390 
1391 static int arp_seq_show(struct seq_file *seq, void *v)
1392 {
1393         if (v == SEQ_START_TOKEN) {
1394                 seq_puts(seq, "IP address       HW type     Flags       "
1395                               "HW address            Mask     Device\n");
1396         } else {
1397                 struct neigh_seq_state *state = seq->private;
1398 
1399                 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1400                         arp_format_pneigh_entry(seq, v);
1401                 else
1402                         arp_format_neigh_entry(seq, v);
1403         }
1404 
1405         return 0;
1406 }
1407 
1408 static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1409 {
1410         /* Don't want to confuse "arp -a" w/ magic entries,
1411          * so we tell the generic iterator to skip NUD_NOARP.
1412          */
1413         return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1414 }
1415 
1416 /* ------------------------------------------------------------------------ */
1417 
1418 static const struct seq_operations arp_seq_ops = {
1419         .start  = arp_seq_start,
1420         .next   = neigh_seq_next,
1421         .stop   = neigh_seq_stop,
1422         .show   = arp_seq_show,
1423 };
1424 
1425 /* ------------------------------------------------------------------------ */
1426 
1427 static int __net_init arp_net_init(struct net *net)
1428 {
1429         if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops,
1430                         sizeof(struct neigh_seq_state)))
1431                 return -ENOMEM;
1432         return 0;
1433 }
1434 
1435 static void __net_exit arp_net_exit(struct net *net)
1436 {
1437         remove_proc_entry("arp", net->proc_net);
1438 }
1439 
1440 static struct pernet_operations arp_net_ops = {
1441         .init = arp_net_init,
1442         .exit = arp_net_exit,
1443 };
1444 
1445 static int __init arp_proc_init(void)
1446 {
1447         return register_pernet_subsys(&arp_net_ops);
1448 }
1449 
1450 #else /* CONFIG_PROC_FS */
1451 
1452 static int __init arp_proc_init(void)
1453 {
1454         return 0;
1455 }
1456 
1457 #endif /* CONFIG_PROC_FS */
1458 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp