/* linux/net/inet/arp.c * * Version: $Id: arp.c,v 1.90 2000/10/04 09:20:56 anton Exp $ * * Copyright (C) 1994 by Florian La Roche * * This module implements the Address Resolution Protocol ARP (RFC 826), * which is used to convert IP addresses (or in the future maybe other * high-level addresses) into a low-level hardware address (like an Ethernet * address). * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Fixes: * Alan Cox : Removed the Ethernet assumptions in * Florian's code * Alan Cox : Fixed some small errors in the ARP * logic * Alan Cox : Allow >4K in /proc * Alan Cox : Make ARP add its own protocol entry * Ross Martin : Rewrote arp_rcv() and arp_get_info() * Stephen Henson : Add AX25 support to arp_get_info() * Alan Cox : Drop data when a device is downed. * Alan Cox : Use init_timer(). * Alan Cox : Double lock fixes. * Martin Seine : Move the arphdr structure * to if_arp.h for compatibility. * with BSD based programs. * Andrew Tridgell : Added ARP netmask code and * re-arranged proxy handling. * Alan Cox : Changed to use notifiers. * Niibe Yutaka : Reply for this device or proxies only. * Alan Cox : Don't proxy across hardware types! * Jonathan Naylor : Added support for NET/ROM. * Mike Shaver : RFC1122 checks. * Jonathan Naylor : Only lookup the hardware address for * the correct hardware type. * Germano Caronni : Assorted subtle races. * Craig Schlenter : Don't modify permanent entry * during arp_rcv. * Russ Nelson : Tidied up a few bits. * Alexey Kuznetsov: Major changes to caching and behaviour, * eg intelligent arp probing and * generation * of host down events. * Alan Cox : Missing unlock in device events. * Eckes : ARP ioctl control errors. * Alexey Kuznetsov: Arp free fix. * Manuel Rodriguez: Gratuitous ARP. * Jonathan Layes : Added arpd support through kerneld * message queue (960314) * Mike Shaver : /proc/sys/net/ipv4/arp_* support * Mike McLagan : Routing by source * Stuart Cheshire : Metricom and grat arp fixes * *** FOR 2.1 clean this up *** * Lawrence V. Stefani: (08/12/96) Added FDDI support. * Alan Cox : Took the AP1000 nasty FDDI hack and * folded into the mainstream FDDI code. * Ack spit, Linus how did you allow that * one in... * Jes Sorensen : Make FDDI work again in 2.1.x and * clean up the APFDDI & gen. FDDI bits. * Alexey Kuznetsov: new arp state machine; * now it is in net/core/neighbour.c. */ /* RFC1122 Status: 2.3.2.1 (ARP Cache Validation): MUST provide mechanism to flush stale cache entries (OK) SHOULD be able to configure cache timeout (OK) MUST throttle ARP retransmits (OK) 2.3.2.2 (ARP Packet Queue): SHOULD save at least one packet from each "conversation" with an unresolved IP address. (OK) 950727 -- MS */ #include <linux/types.h> #include <linux/string.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/config.h> #include <linux/socket.h> #include <linux/sockios.h> #include <linux/errno.h> #include <linux/in.h> #include <linux/mm.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/fddidevice.h> #include <linux/if_arp.h> #include <linux/trdevice.h> #include <linux/skbuff.h> #include <linux/proc_fs.h> #include <linux/stat.h> #include <linux/init.h> #ifdef CONFIG_SYSCTL #include <linux/sysctl.h> #endif #include <net/ip.h> #include <net/icmp.h> #include <net/route.h> #include <net/protocol.h> #include <net/tcp.h> #include <net/sock.h> #include <net/arp.h> #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) #include <net/ax25.h> #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) #include <net/netrom.h> #endif #endif #ifdef CONFIG_ATM_CLIP #include <net/atmclip.h> #endif #include <asm/system.h> #include <asm/uaccess.h> /* * Interface to generic neighbour cache. */ static u32 arp_hash(const void *pkey, const struct net_device *dev); static int arp_constructor(struct neighbour *neigh); static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); static void parp_redo(struct sk_buff *skb); static struct neigh_ops arp_generic_ops = { AF_INET, NULL, arp_solicit, arp_error_report, neigh_resolve_output, neigh_connected_output, dev_queue_xmit, dev_queue_xmit }; static struct neigh_ops arp_hh_ops = { AF_INET, NULL, arp_solicit, arp_error_report, neigh_resolve_output, neigh_resolve_output, dev_queue_xmit, dev_queue_xmit }; static struct neigh_ops arp_direct_ops = { AF_INET, NULL, NULL, NULL, dev_queue_xmit, dev_queue_xmit, dev_queue_xmit, dev_queue_xmit }; struct neigh_ops arp_broken_ops = { AF_INET, NULL, arp_solicit, arp_error_report, neigh_compat_output, neigh_compat_output, dev_queue_xmit, dev_queue_xmit, }; struct neigh_table arp_tbl = { NULL, AF_INET, sizeof(struct neighbour) + 4, 4, arp_hash, arp_constructor, NULL, NULL, parp_redo, "arp_cache", { NULL, NULL, &arp_tbl, 0, NULL, NULL, 30*HZ, 1*HZ, 60*HZ, 30*HZ, 5*HZ, 3, 3, 0, 3, 1*HZ, (8*HZ)/10, 64, 1*HZ }, 30*HZ, 128, 512, 1024, }; 201 int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir) { 203 switch (dev->type) { 204 case ARPHRD_ETHER: 205 case ARPHRD_FDDI: 206 case ARPHRD_IEEE802: ip_eth_mc_map(addr, haddr) ; 208 return 0 ; 209 case ARPHRD_IEEE802_TR: ip_tr_mc_map(addr, haddr) ; 211 return 0; 212 default: 213 if (dir) { memcpy(haddr, dev->broadcast, dev->addr_len); 215 return 0; } } 218 return -EINVAL; } 222 static u32 arp_hash(const void *pkey, const struct net_device *dev) { u32 hash_val; hash_val = *(u32*)pkey; hash_val ^= (hash_val>>16); hash_val ^= hash_val>>8; hash_val ^= hash_val>>3; hash_val = (hash_val^dev->ifindex)&NEIGH_HASHMASK; 232 return hash_val; } 235 static int arp_constructor(struct neighbour *neigh) { u32 addr = *(u32*)neigh->primary_key; struct net_device *dev = neigh->dev; struct in_device *in_dev = in_dev_get(dev); 241 if (in_dev == NULL) 242 return -EINVAL; neigh->type = inet_addr_type(addr); 245 if (in_dev->arp_parms) neigh->parms = in_dev->arp_parms; in_dev_put(in_dev); 250 if (dev->hard_header == NULL) { neigh->nud_state = NUD_NOARP; neigh->ops = &arp_direct_ops; neigh->output = neigh->ops->queue_xmit; 254 } else { /* Good devices (checked by reading texts, but only Ethernet is tested) ARPHRD_ETHER: (ethernet, apfddi) ARPHRD_FDDI: (fddi) ARPHRD_IEEE802: (tr) ARPHRD_METRICOM: (strip) ARPHRD_ARCNET: etc. etc. etc. ARPHRD_IPDDP will also work, if author repairs it. I did not it, because this driver does not work even in old paradigm. */ #if 1 /* So... these "amateur" devices are hopeless. The only thing, that I can say now: It is very sad that we need to keep ugly obsolete code to make them happy. They should be moved to more reasonable state, now they use rebuild_header INSTEAD OF hard_start_xmit!!! Besides that, they are sort of out of date (a lot of redundant clones/copies, useless in 2.1), I wonder why people believe that they work. */ 282 switch (dev->type) { 283 default: 284 break; 285 case ARPHRD_ROSE: #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) case ARPHRD_AX25: #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) case ARPHRD_NETROM: #endif neigh->ops = &arp_broken_ops; neigh->output = neigh->ops->output; return 0; #endif ;} #endif 297 if (neigh->type == RTN_MULTICAST) { neigh->nud_state = NUD_NOARP; arp_mc_map(addr, neigh->ha, dev, 1); 300 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { neigh->nud_state = NUD_NOARP; memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 303 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { neigh->nud_state = NUD_NOARP; memcpy(neigh->ha, dev->broadcast, dev->addr_len); } 307 if (dev->hard_header_cache) neigh->ops = &arp_hh_ops; 309 else neigh->ops = &arp_generic_ops; 311 if (neigh->nud_state&NUD_VALID) neigh->output = neigh->ops->connected_output; 313 else neigh->output = neigh->ops->output; } 316 return 0; } 319 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) { dst_link_failure(skb); kfree_skb(skb); } 325 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) { u32 saddr; u8 *dst_ha = NULL; struct net_device *dev = neigh->dev; u32 target = *(u32*)neigh->primary_key; int probes = atomic_read(&neigh->probes); 333 if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL) saddr = skb->nh.iph->saddr; 335 else saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 338 if ((probes -= neigh->parms->ucast_probes) < 0) { 339 if (!(neigh->nud_state&NUD_VALID)) printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); dst_ha = neigh->ha; 342 read_lock_bh(&neigh->lock); 343 } else if ((probes -= neigh->parms->app_probes) < 0) { #ifdef CONFIG_ARPD neigh_app_ns(neigh); #endif 347 return; } arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, dst_ha, dev->dev_addr, NULL); 352 if (dst_ha) 353 read_unlock_bh(&neigh->lock); } /* OBSOLETE FUNCTIONS */ /* * Find an arp mapping in the cache. If not found, post a request. * * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, * even if it exists. It is supposed that skb->dev was mangled * by a virtual device (eql, shaper). Nobody but broken devices * is allowed to use this function, it is scheduled to be removed. --ANK */ 367 static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev) { 369 switch (addr_hint) { 370 case RTN_LOCAL: printk(KERN_DEBUG "ARP: arp called for own IP address\n"); memcpy(haddr, dev->dev_addr, dev->addr_len); 373 return 1; 374 case RTN_MULTICAST: arp_mc_map(paddr, haddr, dev, 1); 376 return 1; 377 case RTN_BROADCAST: memcpy(haddr, dev->broadcast, dev->addr_len); 379 return 1; } 381 return 0; } 385 int arp_find(unsigned char *haddr, struct sk_buff *skb) { struct net_device *dev = skb->dev; u32 paddr; struct neighbour *n; 391 if (!skb->dst) { printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); kfree_skb(skb); 394 return 1; } paddr = ((struct rtable*)skb->dst)->rt_gateway; 399 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev)) 400 return 0; n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 404 if (n) { n->used = jiffies; 406 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { 407 read_lock_bh(&n->lock); memcpy(haddr, n->ha, dev->addr_len); 409 read_unlock_bh(&n->lock); neigh_release(n); 411 return 0; } neigh_release(n); 414 } else kfree_skb(skb); 416 return 1; } /* END OF OBSOLETE FUNCTIONS */ 421 int arp_bind_neighbour(struct dst_entry *dst) { struct net_device *dev = dst->dev; struct neighbour *n = dst->neighbour; 426 if (dev == NULL) 427 return -EINVAL; 428 if (n == NULL) { u32 nexthop = ((struct rtable*)dst)->rt_gateway; 430 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) nexthop = 0; n = __neigh_lookup_errno( #ifdef CONFIG_ATM_CLIP dev->type == ARPHRD_ATM ? &clip_tbl : #endif &arp_tbl, &nexthop, dev); 437 if (IS_ERR(n)) 438 return PTR_ERR(n); dst->neighbour = n; } 441 return 0; } /* * Interface to link layer: send routine and receive handler. */ /* * Create and send an arp packet. If (dest_hw == NULL), we create a broadcast * message. */ 453 void arp_send(int type, int ptype, u32 dest_ip, struct net_device *dev, u32 src_ip, unsigned char *dest_hw, unsigned char *src_hw, unsigned char *target_hw) { struct sk_buff *skb; struct arphdr *arp; unsigned char *arp_ptr; /* * No arp on this interface. */ 466 if (dev->flags&IFF_NOARP) 467 return; /* * Allocate a buffer */ skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) + dev->hard_header_len + 15, GFP_ATOMIC); 475 if (skb == NULL) 476 return; skb_reserve(skb, (dev->hard_header_len+15)&~15); skb->nh.raw = skb->data; arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4)); skb->dev = dev; skb->protocol = __constant_htons (ETH_P_ARP); 483 if (src_hw == NULL) src_hw = dev->dev_addr; 485 if (dest_hw == NULL) dest_hw = dev->broadcast; /* * Fill the device header for the ARP frame */ if (dev->hard_header && 492 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0) 493 goto out; /* * Fill out the arp protocol part. * * The arp hardware type should match the device type, except for FDDI, * which (according to RFC 1390) should always equal 1 (Ethernet). */ /* * Exceptions everywhere. AX.25 uses the AX.25 PID value not the * DIX code for the protocol. Make these device structure fields. */ 505 switch (dev->type) { 506 default: arp->ar_hrd = htons(dev->type); arp->ar_pro = __constant_htons(ETH_P_IP); 509 break; #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) case ARPHRD_AX25: arp->ar_hrd = __constant_htons(ARPHRD_AX25); arp->ar_pro = __constant_htons(AX25_P_IP); break; #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) case ARPHRD_NETROM: arp->ar_hrd = __constant_htons(ARPHRD_NETROM); arp->ar_pro = __constant_htons(AX25_P_IP); break; #endif #endif #ifdef CONFIG_FDDI case ARPHRD_FDDI: arp->ar_hrd = __constant_htons(ARPHRD_ETHER); arp->ar_pro = __constant_htons(ETH_P_IP); break; #endif #ifdef CONFIG_TR case ARPHRD_IEEE802_TR: arp->ar_hrd = __constant_htons(ARPHRD_IEEE802); arp->ar_pro = __constant_htons(ETH_P_IP); break; #endif } arp->ar_hln = dev->addr_len; arp->ar_pln = 4; arp->ar_op = htons(type); arp_ptr=(unsigned char *)(arp+1); memcpy(arp_ptr, src_hw, dev->addr_len); arp_ptr+=dev->addr_len; memcpy(arp_ptr, &src_ip,4); arp_ptr+=4; 549 if (target_hw != NULL) memcpy(arp_ptr, target_hw, dev->addr_len); 551 else memset(arp_ptr, 0, dev->addr_len); arp_ptr+=dev->addr_len; memcpy(arp_ptr, &dest_ip, 4); skb->dev = dev; dev_queue_xmit(skb); 558 return; out: kfree_skb(skb); } 564 static void parp_redo(struct sk_buff *skb) { arp_rcv(skb, skb->dev, NULL); } /* * Receive an arp request by the device layer. */ 573 int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt) { struct arphdr *arp = skb->nh.arph; unsigned char *arp_ptr= (unsigned char *)(arp+1); struct rtable *rt; unsigned char *sha, *tha; u32 sip, tip; u16 dev_type = dev->type; int addr_type; struct in_device *in_dev = in_dev_get(dev); struct neighbour *n; /* * The hardware length of the packet should match the hardware length * of the device. Similarly, the hardware types should match. The * device should be ARP-able. Also, if pln is not 4, then the lookup * is not from an IP number. We can't currently handle this, so toss * it. */ if (in_dev == NULL || arp->ar_hln != dev->addr_len || dev->flags & IFF_NOARP || skb->pkt_type == PACKET_OTHERHOST || skb->pkt_type == PACKET_LOOPBACK || 597 arp->ar_pln != 4) 598 goto out; 600 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 601 goto out_of_mem; 603 switch (dev_type) { 604 default: 605 if (arp->ar_pro != __constant_htons(ETH_P_IP)) 606 goto out; 607 if (htons(dev_type) != arp->ar_hrd) 608 goto out; 609 break; #ifdef CONFIG_NET_ETHERNET 611 case ARPHRD_ETHER: /* * ETHERNET devices will accept ARP hardware types of either * 1 (Ethernet) or 6 (IEEE 802.2). */ if (arp->ar_hrd != __constant_htons(ARPHRD_ETHER) && 617 arp->ar_hrd != __constant_htons(ARPHRD_IEEE802)) 618 goto out; 619 if (arp->ar_pro != __constant_htons(ETH_P_IP)) 620 goto out; 621 break; #endif #ifdef CONFIG_TR case ARPHRD_IEEE802_TR: /* * Token ring devices will accept ARP hardware types of either * 1 (Ethernet) or 6 (IEEE 802.2). */ if (arp->ar_hrd != __constant_htons(ARPHRD_ETHER) && arp->ar_hrd != __constant_htons(ARPHRD_IEEE802)) goto out; if (arp->ar_pro != __constant_htons(ETH_P_IP)) goto out; break; #endif #ifdef CONFIG_FDDI case ARPHRD_FDDI: /* * According to RFC 1390, FDDI devices should accept ARP hardware types * of 1 (Ethernet). However, to be more robust, we'll accept hardware * types of either 1 (Ethernet) or 6 (IEEE 802.2). */ if (arp->ar_hrd != __constant_htons(ARPHRD_ETHER) && arp->ar_hrd != __constant_htons(ARPHRD_IEEE802)) goto out; if (arp->ar_pro != __constant_htons(ETH_P_IP)) goto out; break; #endif #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) case ARPHRD_AX25: if (arp->ar_pro != __constant_htons(AX25_P_IP)) goto out; if (arp->ar_hrd != __constant_htons(ARPHRD_AX25)) goto out; break; #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) case ARPHRD_NETROM: if (arp->ar_pro != __constant_htons(AX25_P_IP)) goto out; if (arp->ar_hrd != __constant_htons(ARPHRD_NETROM)) goto out; break; #endif #endif } /* Understand only these message types */ if (arp->ar_op != __constant_htons(ARPOP_REPLY) && 671 arp->ar_op != __constant_htons(ARPOP_REQUEST)) 672 goto out; /* * Extract fields */ sha=arp_ptr; arp_ptr += dev->addr_len; memcpy(&sip, arp_ptr, 4); arp_ptr += 4; tha=arp_ptr; arp_ptr += dev->addr_len; memcpy(&tip, arp_ptr, 4); /* * Check for bad requests for 127.x.x.x and requests for multicast * addresses. If this is one such, delete it. */ 688 if (LOOPBACK(tip) || MULTICAST(tip)) 689 goto out; /* * Process entry. The idea here is we want to send a reply if it is a * request for us or if it is a request for someone else that we hold * a proxy for. We want to add an entry to our cache if it is a reply * to us or if it is a request for our address. * (The assumption for this last is that if someone is requesting our * address, they are probably intending to talk to us, so it saves time * if we cache their address. Their address is also probably not in * our cache, since ours is not in their cache.) * * Putting this another way, we only care about replies if they are to * us, in which case we add them to the cache. For requests, we care * about those for us and those for our proxies. We reply to both, * and in the case of requests for us we add the requester to the arp * cache. */ /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 709 if (sip == 0) { if (arp->ar_op == __constant_htons(ARPOP_REQUEST) && 711 inet_addr_type(tip) == RTN_LOCAL) arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr); 713 goto out; } if (arp->ar_op == __constant_htons(ARPOP_REQUEST) && 717 ip_route_input(skb, tip, sip, 0, dev) == 0) { rt = (struct rtable*)skb->dst; addr_type = rt->rt_type; 722 if (addr_type == RTN_LOCAL) { n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 724 if (n) { arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); neigh_release(n); } 728 goto out; 729 } else if (IN_DEV_FORWARD(in_dev)) { if ((rt->rt_flags&RTCF_DNAT) || (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && 732 (IN_DEV_PROXY_ARP(in_dev) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) { n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 734 if (n) neigh_release(n); if (skb->stamp.tv_sec == 0 || skb->pkt_type == PACKET_HOST || 739 in_dev->arp_parms->proxy_delay == 0) { arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 741 } else { pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); in_dev_put(in_dev); 744 return 0; } 746 goto out; } } } /* Update our ARP tables */ n = __neigh_lookup(&arp_tbl, &sip, dev, 0); #ifdef CONFIG_IP_ACCEPT_UNSOLICITED_ARP /* Unsolicited ARP is not accepted by default. It is possible, that this option should be enabled for some devices (strip is candidate) */ if (n == NULL && arp->ar_op == __constant_htons(ARPOP_REPLY) && inet_addr_type(sip) == RTN_UNICAST) n = __neigh_lookup(&arp_tbl, &sip, dev, -1); #endif 766 if (n) { int state = NUD_REACHABLE; int override = 0; /* If several different ARP replies follows back-to-back, use the FIRST one. It is possible, if several proxy agents are active. Taking the first reply prevents arp trashing and chooses the fastest router. */ 775 if (jiffies - n->updated >= n->parms->locktime) override = 1; /* Broadcast replies and request packets do not assert neighbour reachability. */ if (arp->ar_op != __constant_htons(ARPOP_REPLY) || 782 skb->pkt_type != PACKET_HOST) state = NUD_STALE; neigh_update(n, sha, state, override, 1); neigh_release(n); } out: kfree_skb(skb); 790 if (in_dev) in_dev_put(in_dev); out_of_mem: 793 return 0; } /* * User level interface (ioctl, /proc) */ /* * Set (create) an ARP cache entry. */ 806 int arp_req_set(struct arpreq *r, struct net_device * dev) { u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; struct neighbour *neigh; int err; 812 if (r->arp_flags&ATF_PUBL) { u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 814 if (mask && mask != 0xFFFFFFFF) 815 return -EINVAL; 816 if (!dev && (r->arp_flags & ATF_COM)) { dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data); 818 if (!dev) 819 return -ENODEV; } 821 if (mask) { 822 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) 823 return -ENOBUFS; 824 return 0; } 826 if (dev == NULL) { ipv4_devconf.proxy_arp = 1; 828 return 0; } 830 if (__in_dev_get(dev)) { __in_dev_get(dev)->cnf.proxy_arp = 1; 832 return 0; } 834 return -ENXIO; } 837 if (r->arp_flags & ATF_PERM) r->arp_flags |= ATF_COM; 839 if (dev == NULL) { struct rtable * rt; 841 if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0) 842 return err; dev = rt->u.dst.dev; ip_rt_put(rt); 845 if (!dev) 846 return -EINVAL; } 848 if (r->arp_ha.sa_family != dev->type) 849 return -EINVAL; neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); err = PTR_ERR(neigh); 853 if (!IS_ERR(neigh)) { unsigned state = NUD_STALE; 855 if (r->arp_flags & ATF_PERM) state = NUD_PERMANENT; err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? r->arp_ha.sa_data : NULL, state, 1, 0); neigh_release(neigh); } 861 return err; } 864 static unsigned arp_state_to_flags(struct neighbour *neigh) { unsigned flags = 0; 867 if (neigh->nud_state&NUD_PERMANENT) flags = ATF_PERM|ATF_COM; 869 else if (neigh->nud_state&NUD_VALID) flags = ATF_COM; 871 return flags; } /* * Get an ARP cache entry. */ 878 static int arp_req_get(struct arpreq *r, struct net_device *dev) { u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; struct neighbour *neigh; int err = -ENXIO; neigh = neigh_lookup(&arp_tbl, &ip, dev); 885 if (neigh) { 886 read_lock_bh(&neigh->lock); memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); r->arp_flags = arp_state_to_flags(neigh); 889 read_unlock_bh(&neigh->lock); r->arp_ha.sa_family = dev->type; strncpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); neigh_release(neigh); err = 0; } 895 return err; } 898 int arp_req_delete(struct arpreq *r, struct net_device * dev) { int err; u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; struct neighbour *neigh; 904 if (r->arp_flags & ATF_PUBL) { u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 906 if (mask == 0xFFFFFFFF) 907 return pneigh_delete(&arp_tbl, &ip, dev); 908 if (mask == 0) { 909 if (dev == NULL) { ipv4_devconf.proxy_arp = 0; 911 return 0; } 913 if (__in_dev_get(dev)) { __in_dev_get(dev)->cnf.proxy_arp = 0; 915 return 0; } 917 return -ENXIO; } 919 return -EINVAL; } 922 if (dev == NULL) { struct rtable * rt; 924 if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0) 925 return err; dev = rt->u.dst.dev; ip_rt_put(rt); 928 if (!dev) 929 return -EINVAL; } err = -ENXIO; neigh = neigh_lookup(&arp_tbl, &ip, dev); 933 if (neigh) { 934 if (neigh->nud_state&~NUD_NOARP) err = neigh_update(neigh, NULL, NUD_FAILED, 1, 0); neigh_release(neigh); } 938 return err; } /* * Handle an ARP layer I/O control request. */ 945 int arp_ioctl(unsigned int cmd, void *arg) { int err; struct arpreq r; struct net_device * dev = NULL; 951 switch(cmd) { 952 case SIOCDARP: 953 case SIOCSARP: 954 if (!capable(CAP_NET_ADMIN)) 955 return -EPERM; 956 case SIOCGARP: err = copy_from_user(&r, arg, sizeof(struct arpreq)); 958 if (err) 959 return -EFAULT; 960 break; 961 default: 962 return -EINVAL; } 965 if (r.arp_pa.sa_family != AF_INET) 966 return -EPFNOSUPPORT; if (!(r.arp_flags & ATF_PUBL) && 969 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 970 return -EINVAL; 971 if (!(r.arp_flags & ATF_NETMASK)) ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr=__constant_htonl(0xFFFFFFFFUL); rtnl_lock(); 975 if (r.arp_dev[0]) { err = -ENODEV; 977 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL) 978 goto out; /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 981 if (!r.arp_ha.sa_family) r.arp_ha.sa_family = dev->type; err = -EINVAL; 984 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 985 goto out; 986 } else if (cmd == SIOCGARP) { err = -ENODEV; 988 goto out; } 991 switch(cmd) { 992 case SIOCDARP: err = arp_req_delete(&r, dev); 994 break; 995 case SIOCSARP: err = arp_req_set(&r, dev); 997 break; 998 case SIOCGARP: err = arp_req_get(&r, dev); 1000 if (!err && copy_to_user(arg, &r, sizeof(r))) err = -EFAULT; 1002 break; } out: rtnl_unlock(); 1006 return err; } /* * Write the contents of the ARP cache to a PROCfs file. */ #ifndef CONFIG_PROC_FS static int arp_get_info(char *buffer, char **start, off_t offset, int length) { return 0; } #else #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) static char *ax2asc2(ax25_address *a, char *buf); #endif #define HBUFFERLEN 30 1020 static int arp_get_info(char *buffer, char **start, off_t offset, int length) { int len=0; off_t pos=0; int size; char hbuffer[HBUFFERLEN]; int i,j,k; const char hexbuf[] = "0123456789ABCDEF"; size = sprintf(buffer,"IP address HW type Flags HW address Mask Device\n"); pos+=size; len+=size; 1034 for(i=0; i<=NEIGH_HASHMASK; i++) { struct neighbour *n; 1036 read_lock_bh(&arp_tbl.lock); 1037 for (n=arp_tbl.hash_buckets[i]; n; n=n->next) { struct net_device *dev = n->dev; int hatype = dev->type; /* Do not confuse users "arp -a" with magic entries */ 1042 if (!(n->nud_state&~NUD_NOARP)) 1043 continue; read_lock(&n->lock); /* * Convert hardware address to XX:XX:XX:XX ... form. */ #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) ax2asc2((ax25_address *)n->ha, hbuffer); else { #endif 1055 for (k=0,j=0;k<HBUFFERLEN-3 && j<dev->addr_len;j++) { hbuffer[k++]=hexbuf[(n->ha[j]>>4)&15 ]; hbuffer[k++]=hexbuf[n->ha[j]&15 ]; hbuffer[k++]=':'; } hbuffer[--k]=0; #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) } #endif { char tbuf[16]; sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); size = sprintf(buffer+len, "%-16s 0x%-10x0x%-10x%s" " * %s\n", tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); } 1078 read_unlock(&n->lock); len += size; pos += size; 1083 if (pos <= offset) len=0; 1085 if (pos >= offset+length) { 1086 read_unlock_bh(&arp_tbl.lock); 1087 goto done; } } 1090 read_unlock_bh(&arp_tbl.lock); } 1093 for (i=0; i<=PNEIGH_HASHMASK; i++) { struct pneigh_entry *n; 1095 for (n=arp_tbl.phash_buckets[i]; n; n=n->next) { struct net_device *dev = n->dev; int hatype = dev ? dev->type : 0; { char tbuf[16]; sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key)); size = sprintf(buffer+len, "%-16s 0x%-10x0x%-10x%s" " * %s\n", tbuf, hatype, ATF_PUBL|ATF_PERM, "00:00:00:00:00:00", dev ? dev->name : "*"); } len += size; pos += size; 1114 if (pos <= offset) len=0; 1116 if (pos >= offset+length) 1117 goto done; } } done: *start = buffer+len-(pos-offset); /* Start of wanted data */ len = pos-offset; /* Start slop */ 1125 if (len>length) len = length; /* Ending slop */ 1127 if (len<0) len = 0; 1129 return len; } #endif /* Note, that it is not on notifier chain. It is necessary, that this routine was called after route cache will be flushed. */ 1137 void arp_ifdown(struct net_device *dev) { neigh_ifdown(&arp_tbl, dev); } /* * Called once on startup. */ static struct packet_type arp_packet_type = { __constant_htons(ETH_P_ARP), NULL, /* All devices */ arp_rcv, (void*)1, NULL }; 1156 void __init arp_init (void) { neigh_table_init(&arp_tbl); dev_add_pack(&arp_packet_type); proc_net_create ("arp", 0, arp_get_info); #ifdef CONFIG_SYSCTL neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, NET_IPV4_NEIGH, "ipv4"); #endif } #ifdef CONFIG_PROC_FS #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) /* * ax25 -> ASCII conversion */ char *ax2asc2(ax25_address *a, char *buf) { char c, *s; int n; for (n = 0, s = buf; n < 6; n++) { c = (a->ax25_call[n] >> 1) & 0x7F; if (c != ' ') *s++ = c; } *s++ = '-'; if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { *s++ = '1'; n -= 10; } *s++ = n + '0'; *s++ = '\0'; if (*buf == '\0' || *buf == '-') return "*"; return buf; } #endif #endif