/* linux/net/inet/arp.c * * 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). * * FIXME: * Experiment with better retransmit timers * Clean up the timer deletions * If you create a proxy entry set your interface address to the address * and then delete it, proxies may get out of sync with reality - check this * * 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! */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ip.h" #include "route.h" #include "protocol.h" #include "tcp.h" #include #include "sock.h" #include "arp.h" #ifdef CONFIG_AX25 #include "ax25.h" #endif /* * This structure defines the ARP mapping cache. As long as we make changes * in this structure, we keep interrupts of. But normally we can copy the * hardware address and the device pointer in a local variable and then make * any "long calls" to send a packet out. */ struct arp_table { struct arp_table *next; /* Linked entry list */ unsigned long last_used; /* For expiry */ unsigned int flags; /* Control status */ unsigned long ip; /* ip address of entry */ unsigned long mask; /* netmask - used for generalised proxy arps (tridge) */ unsigned char ha[MAX_ADDR_LEN]; /* Hardware address */ unsigned char hlen; /* Length of hardware address */ unsigned short htype; /* Type of hardware in use */ struct device *dev; /* Device the entry is tied to */ /* * The following entries are only used for unresolved hw addresses. */ struct timer_list timer; /* expire timer */ int retries; /* remaining retries */ struct sk_buff_head skb; /* list of queued packets */ }; /* * Configurable Parameters (don't touch unless you know what you are doing */ /* * If an arp request is send, ARP_RES_TIME is the timeout value until the * next request is send. */ #define ARP_RES_TIME (250*(HZ/10)) /* * The number of times an arp request is send, until the host is * considered unreachable. */ #define ARP_MAX_TRIES 3 /* * After that time, an unused entry is deleted from the arp table. */ #define ARP_TIMEOUT (600*HZ) /* * How often is the function 'arp_check_retries' called. * An entry is invalidated in the time between ARP_TIMEOUT and * (ARP_TIMEOUT+ARP_CHECK_INTERVAL). */ #define ARP_CHECK_INTERVAL (60 * HZ) enum proxy { PROXY_EXACT=0, PROXY_ANY, PROXY_NONE, }; /* Forward declarations. */ static void arp_check_expire (unsigned long); static struct arp_table *arp_lookup(unsigned long paddr, enum proxy proxy); static struct timer_list arp_timer = { NULL, NULL, ARP_CHECK_INTERVAL, 0L, &arp_check_expire }; /* * The default arp netmask is just 255.255.255.255 which means it's * a single machine entry. Only proxy entries can have other netmasks * */ #define DEF_ARP_NETMASK (~0) /* * The size of the hash table. Must be a power of two. * Maybe we should remove hashing in the future for arp and concentrate * on Patrick Schaaf's Host-Cache-Lookup... */ #define ARP_TABLE_SIZE 16 /* The ugly +1 here is to cater for proxy entries. They are put in their own list for efficiency of lookup. If you don't want to find a proxy entry then don't look in the last entry, otherwise do */ #define FULL_ARP_TABLE_SIZE (ARP_TABLE_SIZE+1) struct arp_table *arp_tables[FULL_ARP_TABLE_SIZE] = { NULL, }; /* * The last bits in the IP address are used for the cache lookup. * A special entry is used for proxy arp entries */ #define HASH(paddr) (htonl(paddr) & (ARP_TABLE_SIZE - 1)) #define PROXY_HASH ARP_TABLE_SIZE /* * Check if there are too old entries and remove them. If the ATF_PERM * flag is set, they are always left in the arp cache (permanent entry). * Note: Only fully resolved entries, which don't have any packets in * the queue, can be deleted, since ARP_TIMEOUT is much greater than * ARP_MAX_TRIES*ARP_RES_TIME. */ static void arp_check_expire(unsigned long dummy) { int i; unsigned long now = jiffies; unsigned long flags; save_flags(flags); cli(); for (i = 0; i < FULL_ARP_TABLE_SIZE; i++) { struct arp_table *entry; struct arp_table **pentry = &arp_tables[i]; while ((entry = *pentry) != NULL) { if ((now - entry->last_used) > ARP_TIMEOUT && !(entry->flags & ATF_PERM)) { *pentry = entry->next; /* remove from list */ del_timer(&entry->timer); /* Paranoia */ kfree_s(entry, sizeof(struct arp_table)); } else pentry = &entry->next; /* go to next entry */ } } restore_flags(flags); /* * Set the timer again. */ del_timer(&arp_timer); arp_timer.expires = ARP_CHECK_INTERVAL; add_timer(&arp_timer); } /* * Release all linked skb's and the memory for this entry. */ static void arp_release_entry(struct arp_table *entry) { struct sk_buff *skb; unsigned long flags; save_flags(flags); cli(); /* Release the list of `skb' pointers. */ while ((skb = skb_dequeue(&entry->skb)) != NULL) { skb_device_lock(skb); restore_flags(flags); dev_kfree_skb(skb, FREE_WRITE); } restore_flags(flags); del_timer(&entry->timer); kfree_s(entry, sizeof(struct arp_table)); return; } /* * Purge a device from the ARP queue */ int arp_device_event(unsigned long event, void *ptr) { struct device *dev=ptr; int i; unsigned long flags; if(event!=NETDEV_DOWN) return NOTIFY_DONE; /* * This is a bit OTT - maybe we need some arp semaphores instead. */ save_flags(flags); cli(); for (i = 0; i < FULL_ARP_TABLE_SIZE; i++) { struct arp_table *entry; struct arp_table **pentry = &arp_tables[i]; while ((entry = *pentry) != NULL) { if(entry->dev==dev) { *pentry = entry->next; /* remove from list */ del_timer(&entry->timer); /* Paranoia */ kfree_s(entry, sizeof(struct arp_table)); } else pentry = &entry->next; /* go to next entry */ } } restore_flags(flags); return NOTIFY_DONE; } /* * Create and send an arp packet. If (dest_hw == NULL), we create a broadcast * message. */ void arp_send(int type, int ptype, unsigned long dest_ip, struct device *dev, unsigned long src_ip, unsigned char *dest_hw, unsigned char *src_hw) { struct sk_buff *skb; struct arphdr *arp; unsigned char *arp_ptr; /* * No arp on this interface. */ if(dev->flags&IFF_NOARP) return; /* * Allocate a buffer */ skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) + dev->hard_header_len, GFP_ATOMIC); if (skb == NULL) { printk("ARP: no memory to send an arp packet\n"); return; } skb->len = sizeof(struct arphdr) + dev->hard_header_len + 2*(dev->addr_len+4); skb->arp = 1; skb->dev = dev; skb->free = 1; /* * Fill the device header for the ARP frame */ dev->hard_header(skb->data,dev,ptype,dest_hw?dest_hw:dev->broadcast,src_hw?src_hw:NULL,skb->len,skb); /* Fill out the arp protocol part. */ arp = (struct arphdr *) (skb->data + dev->hard_header_len); arp->ar_hrd = htons(dev->type); #ifdef CONFIG_AX25 arp->ar_pro = (dev->type != ARPHRD_AX25)? htons(ETH_P_IP) : htons(AX25_P_IP); #else arp->ar_pro = htons(ETH_P_IP); #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; if (dest_hw != NULL) memcpy(arp_ptr, dest_hw, dev->addr_len); else memset(arp_ptr, 0, dev->addr_len); arp_ptr+=dev->addr_len; memcpy(arp_ptr, &dest_ip, 4); dev_queue_xmit(skb, dev, 0); } /* * This function is called, if an entry is not resolved in ARP_RES_TIME. * Either resend a request, or give it up and free the entry. */ static void arp_expire_request (unsigned long arg) { struct arp_table *entry = (struct arp_table *) arg; struct arp_table **pentry; unsigned long hash; unsigned long flags; save_flags(flags); cli(); /* * Since all timeouts are handled with interrupts enabled, there is a * small chance, that this entry has just been resolved by an incoming * packet. This is the only race condition, but it is handled... */ if (entry->flags & ATF_COM) { restore_flags(flags); return; } if (--entry->retries > 0) { unsigned long ip = entry->ip; struct device *dev = entry->dev; /* Set new timer. */ del_timer(&entry->timer); entry->timer.expires = ARP_RES_TIME; add_timer(&entry->timer); restore_flags(flags); arp_send(ARPOP_REQUEST, ETH_P_ARP, ip, dev, dev->pa_addr, NULL, dev->dev_addr); return; } /* * Arp request timed out. Delete entry and all waiting packets. * If we give each entry a pointer to itself, we don't have to * loop through everything again. Maybe hash is good enough, but * I will look at it later. */ hash = HASH(entry->ip); /* proxy entries shouldn't really time out so this is really only here for completeness */ if (entry->flags & ATF_PUBL) pentry = &arp_tables[PROXY_HASH]; else pentry = &arp_tables[hash]; while (*pentry != NULL) { if (*pentry == entry) { *pentry = entry->next; /* delete from linked list */ del_timer(&entry->timer); restore_flags(flags); arp_release_entry(entry); return; } pentry = &(*pentry)->next; } restore_flags(flags); printk("Possible ARP queue corruption.\n"); /* * We should never arrive here. */ } /* * This will try to retransmit everything on the queue. */ static void arp_send_q(struct arp_table *entry, unsigned char *hw_dest) { struct sk_buff *skb; unsigned long flags; /* * Empty the entire queue, building its data up ready to send */ if(!(entry->flags&ATF_COM)) { printk("arp_send_q: incomplete entry for %s\n", in_ntoa(entry->ip)); return; } save_flags(flags); cli(); while((skb = skb_dequeue(&entry->skb)) != NULL) { IS_SKB(skb); skb_device_lock(skb); restore_flags(flags); if(!skb->dev->rebuild_header(skb->data,skb->dev,skb->raddr,skb)) { skb->arp = 1; if(skb->sk==NULL) dev_queue_xmit(skb, skb->dev, 0); else dev_queue_xmit(skb,skb->dev,skb->sk->priority); } else { /* This routine is only ever called when 'entry' is complete. Thus this can't fail. */ printk("arp_send_q: The impossible occurred. Please notify Alan.\n"); printk("arp_send_q: active entity %s\n",in_ntoa(entry->ip)); printk("arp_send_q: failed to find %s\n",in_ntoa(skb->raddr)); } } restore_flags(flags); } /* * Delete an ARP mapping entry in the cache. */ void arp_destroy(unsigned long ip_addr, int force) { int checked_proxies = 0; struct arp_table *entry; struct arp_table **pentry; unsigned long hash = HASH(ip_addr); ugly: cli(); pentry = &arp_tables[hash]; if (! *pentry) /* also check proxy entries */ pentry = &arp_tables[PROXY_HASH]; while ((entry = *pentry) != NULL) { if (entry->ip == ip_addr) { if ((entry->flags & ATF_PERM) && !force) return; *pentry = entry->next; del_timer(&entry->timer); sti(); arp_release_entry(entry); /* this would have to be cleaned up */ goto ugly; /* perhaps like this ? cli(); entry = *pentry; */ } pentry = &entry->next; if (!checked_proxies && ! *pentry) { /* ugly. we have to make sure we check proxy entries as well */ checked_proxies = 1; pentry = &arp_tables[PROXY_HASH]; } } sti(); } /* * Receive an arp request by the device layer. Maybe I rewrite it, to * use the incoming packet for the reply. The time for the current * "overhead" isn't that high... */ int arp_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *pt) { /* * We shouldn't use this type conversion. Check later. */ struct arphdr *arp = (struct arphdr *)skb->h.raw; unsigned char *arp_ptr= (unsigned char *)(arp+1); struct arp_table *entry; struct arp_table *proxy_entry; int addr_hint,hlen,htype; unsigned long hash; unsigned char ha[MAX_ADDR_LEN]; /* So we can enable ints again. */ long sip,tip; unsigned char *sha,*tha; /* * 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 (arp->ar_hln != dev->addr_len || dev->type != ntohs(arp->ar_hrd) || dev->flags & IFF_NOARP || arp->ar_pln != 4) { kfree_skb(skb, FREE_READ); return 0; } /* * Another test. * The logic here is that the protocol being looked up by arp should * match the protocol the device speaks. If it doesn't, there is a * problem, so toss the packet. */ switch(dev->type) { #ifdef CONFIG_AX25 case ARPHRD_AX25: if(arp->ar_pro != htons(AX25_P_IP)) { kfree_skb(skb, FREE_READ); return 0; } break; #endif case ARPHRD_ETHER: case ARPHRD_ARCNET: if(arp->ar_pro != htons(ETH_P_IP)) { kfree_skb(skb, FREE_READ); return 0; } break; default: printk("ARP: dev->type mangled!\n"); kfree_skb(skb, FREE_READ); return 0; } /* * Extract fields */ hlen = dev->addr_len; htype = dev->type; sha=arp_ptr; arp_ptr+=hlen; memcpy(&sip,arp_ptr,4); arp_ptr+=4; tha=arp_ptr; arp_ptr+=hlen; memcpy(&tip,arp_ptr,4); /* * Check for bad requests for 127.0.0.1. If this is one such, delete it. */ if(tip == INADDR_LOOPBACK) { kfree_skb(skb, FREE_READ); return 0; } /* * 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. */ addr_hint = ip_chk_addr(tip); if(arp->ar_op == htons(ARPOP_REPLY)) { if(addr_hint!=IS_MYADDR) { /* * Replies to other machines get tossed. */ kfree_skb(skb, FREE_READ); return 0; } /* * Fall through to code below that adds sender to cache. */ } else { /* * It is now an arp request */ /* * Only reply for the real device address or when it's in our proxy tables */ if(tip!=dev->pa_addr) { /* * To get in here, it is a request for someone else. We need to * check if that someone else is one of our proxies. If it isn't, * we can toss it. */ cli(); for(proxy_entry=arp_tables[PROXY_HASH]; proxy_entry; proxy_entry = proxy_entry->next) { /* we will respond to a proxy arp request if the masked arp table ip matches the masked tip. This allows a single proxy arp table entry to be used on a gateway machine to handle all requests for a whole network, rather than having to use a huge number of proxy arp entries and having to keep them uptodate. */ if (proxy_entry->dev != dev && proxy_entry->htype == htype && !((proxy_entry->ip^tip)&proxy_entry->mask)) break; } if (proxy_entry) { memcpy(ha, proxy_entry->ha, hlen); sti(); arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,ha); kfree_skb(skb, FREE_READ); return 0; } else { sti(); kfree_skb(skb, FREE_READ); return 0; } } else { /* * To get here, it must be an arp request for us. We need to reply. */ arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr); } } /* * Now all replies are handled. Next, anything that falls through to here * needs to be added to the arp cache, or have its entry updated if it is * there. */ hash = HASH(sip); cli(); for(entry=arp_tables[hash];entry;entry=entry->next) if(entry->ip==sip && entry->htype==htype) break; if(entry) { /* * Entry found; update it. */ memcpy(entry->ha, sha, hlen); entry->hlen = hlen; entry->last_used = jiffies; if (!(entry->flags & ATF_COM)) { /* * This entry was incomplete. Delete the retransmit timer * and switch to complete status. */ del_timer(&entry->timer); entry->flags |= ATF_COM; sti(); /* * Send out waiting packets. We might have problems, if someone is * manually removing entries right now -- entry might become invalid * underneath us. */ arp_send_q(entry, sha); } else { sti(); } } else { /* * No entry found. Need to add a new entry to the arp table. */ entry = (struct arp_table *)kmalloc(sizeof(struct arp_table),GFP_ATOMIC); if(entry == NULL) { sti(); printk("ARP: no memory for new arp entry\n"); kfree_skb(skb, FREE_READ); return 0; } entry->mask = DEF_ARP_NETMASK; entry->ip = sip; entry->hlen = hlen; entry->htype = htype; entry->flags = ATF_COM; init_timer(&entry->timer); memcpy(entry->ha, sha, hlen); entry->last_used = jiffies; entry->dev = skb->dev; skb_queue_head_init(&entry->skb); entry->next = arp_tables[hash]; arp_tables[hash] = entry; sti(); } /* * Replies have been sent, and entries have been added. All done. */ kfree_skb(skb, FREE_READ); return 0; } /* * Find an arp mapping in the cache. If not found, post a request. */ int arp_find(unsigned char *haddr, unsigned long paddr, struct device *dev, unsigned long saddr, struct sk_buff *skb) { struct arp_table *entry; unsigned long hash; #ifdef CONFIG_IP_MULTICAST unsigned long taddr; #endif switch (ip_chk_addr(paddr)) { case IS_MYADDR: printk("ARP: arp called for own IP address\n"); memcpy(haddr, dev->dev_addr, dev->addr_len); skb->arp = 1; return 0; #ifdef CONFIG_IP_MULTICAST case IS_MULTICAST: if(dev->type==ARPHRD_ETHER || dev->type==ARPHRD_IEEE802) { haddr[0]=0x01; haddr[1]=0x00; haddr[2]=0x5e; taddr=ntohl(paddr); haddr[5]=taddr&0xff; taddr=taddr>>8; haddr[4]=taddr&0xff; taddr=taddr>>8; haddr[3]=taddr&0x7f; return 0; } /* * If a device does not support multicast broadcast the stuff (eg AX.25 for now) */ #endif case IS_BROADCAST: memcpy(haddr, dev->broadcast, dev->addr_len); skb->arp = 1; return 0; } hash = HASH(paddr); cli(); /* * Find an entry */ entry = arp_lookup(paddr, PROXY_NONE); if (entry != NULL) /* It exists */ { if (!(entry->flags & ATF_COM)) { /* * A request was already send, but no reply yet. Thus * queue the packet with the previous attempt */ if (skb != NULL) { skb_queue_tail(&entry->skb, skb); skb_device_unlock(skb); } sti(); return 1; } /* * Update the record */ entry->last_used = jiffies; memcpy(haddr, entry->ha, dev->addr_len); if (skb) skb->arp = 1; sti(); return 0; } /* * Create a new unresolved entry. */ entry = (struct arp_table *) kmalloc(sizeof(struct arp_table), GFP_ATOMIC); if (entry != NULL) { entry->mask = DEF_ARP_NETMASK; entry->ip = paddr; entry->hlen = dev->addr_len; entry->htype = dev->type; entry->flags = 0; memset(entry->ha, 0, dev->addr_len); entry->dev = dev; entry->last_used = jiffies; init_timer(&entry->timer); entry->timer.function = arp_expire_request; entry->timer.data = (unsigned long)entry; entry->timer.expires = ARP_RES_TIME; entry->next = arp_tables[hash]; arp_tables[hash] = entry; add_timer(&entry->timer); entry->retries = ARP_MAX_TRIES; skb_queue_head_init(&entry->skb); if (skb != NULL) { skb_queue_tail(&entry->skb, skb); skb_device_unlock(skb); } } else { if (skb != NULL && skb->free) kfree_skb(skb, FREE_WRITE); } sti(); /* * If we didn't find an entry, we will try to send an ARP packet. */ arp_send(ARPOP_REQUEST, ETH_P_ARP, paddr, dev, saddr, NULL, dev->dev_addr); return 1; } /* * Write the contents of the ARP cache to a PROCfs file. */ #define HBUFFERLEN 30 int arp_get_info(char *buffer, char **start, off_t offset, int length) { int len=0; off_t begin=0; off_t pos=0; int size; struct arp_table *entry; char hbuffer[HBUFFERLEN]; int i,j,k; const char hexbuf[] = "0123456789ABCDEF"; size = sprintf(buffer,"IP address HW type Flags HW address Mask\n"); pos+=size; len+=size; cli(); for(i=0; inext) { /* * Convert hardware address to XX:XX:XX:XX ... form. */ #ifdef CONFIG_AX25 if(entry->htype==ARPHRD_AX25) strcpy(hbuffer,ax2asc((ax25_address *)entry->ha)); else { #endif for(k=0,j=0;khlen;j++) { hbuffer[k++]=hexbuf[ (entry->ha[j]>>4)&15 ]; hbuffer[k++]=hexbuf[ entry->ha[j]&15 ]; hbuffer[k++]=':'; } hbuffer[--k]=0; #ifdef CONFIG_AX25 } #endif size = sprintf(buffer+len, "%-17s0x%-10x0x%-10x%s", in_ntoa(entry->ip), (unsigned int)entry->htype, entry->flags, hbuffer); size += sprintf(buffer+len+size, " %-17s\n", entry->mask==DEF_ARP_NETMASK? "*":in_ntoa(entry->mask)); len+=size; pos=begin+len; if(posoffset+length) break; } } sti(); *start=buffer+(offset-begin); /* Start of wanted data */ len-=(offset-begin); /* Start slop */ if(len>length) len=length; /* Ending slop */ return len; } /* * This will find an entry in the ARP table by looking at the IP address. * If proxy is PROXY_EXACT then only exact IP matches will be allowed * for proxy entries, otherwise the netmask will be used */ static struct arp_table *arp_lookup(unsigned long paddr, enum proxy proxy) { struct arp_table *entry; unsigned long hash = HASH(paddr); for (entry = arp_tables[hash]; entry != NULL; entry = entry->next) if (entry->ip == paddr) break; /* it's possibly a proxy entry (with a netmask) */ if (!entry && proxy != PROXY_NONE) for (entry=arp_tables[PROXY_HASH]; entry != NULL; entry = entry->next) if ((proxy==PROXY_EXACT) ? (entry->ip==paddr) : !((entry->ip^paddr)&entry->mask)) break; return entry; } /* * Set (create) an ARP cache entry. */ static int arp_req_set(struct arpreq *req) { struct arpreq r; struct arp_table *entry; struct sockaddr_in *si; int htype, hlen; unsigned long ip; struct rtable *rt; memcpy_fromfs(&r, req, sizeof(r)); /* We only understand about IP addresses... */ if (r.arp_pa.sa_family != AF_INET) return -EPFNOSUPPORT; /* * Find out about the hardware type. * We have to be compatible with BSD UNIX, so we have to * assume that a "not set" value (i.e. 0) means Ethernet. */ switch (r.arp_ha.sa_family) { case ARPHRD_ETHER: htype = ARPHRD_ETHER; hlen = ETH_ALEN; break; case ARPHRD_ARCNET: htype = ARPHRD_ARCNET; hlen = 1; /* length of arcnet addresses */ break; #ifdef CONFIG_AX25 case ARPHRD_AX25: htype = ARPHRD_AX25; hlen = 7; break; #endif default: return -EPFNOSUPPORT; } si = (struct sockaddr_in *) &r.arp_pa; ip = si->sin_addr.s_addr; if (ip == 0) { printk("ARP: SETARP: requested PA is 0.0.0.0 !\n"); return -EINVAL; } /* * Is it reachable directly ? */ rt = ip_rt_route(ip, NULL, NULL); if (rt == NULL) return -ENETUNREACH; /* * Is there an existing entry for this address? */ cli(); /* * Find the entry */ entry = arp_lookup(ip, PROXY_EXACT); if (entry && (entry->flags & ATF_PUBL) != (r.arp_flags & ATF_PUBL)) { sti(); arp_destroy(ip,1); cli(); entry = NULL; } /* * Do we need to create a new entry */ if (entry == NULL) { unsigned long hash = HASH(ip); if (r.arp_flags & ATF_PUBL) hash = PROXY_HASH; entry = (struct arp_table *) kmalloc(sizeof(struct arp_table), GFP_ATOMIC); if (entry == NULL) { sti(); return -ENOMEM; } entry->ip = ip; entry->hlen = hlen; entry->htype = htype; init_timer(&entry->timer); entry->next = arp_tables[hash]; arp_tables[hash] = entry; skb_queue_head_init(&entry->skb); } /* * We now have a pointer to an ARP entry. Update it! */ memcpy(&entry->ha, &r.arp_ha.sa_data, hlen); entry->last_used = jiffies; entry->flags = r.arp_flags | ATF_COM; if ((entry->flags & ATF_PUBL) && (entry->flags & ATF_NETMASK)) { si = (struct sockaddr_in *) &r.arp_netmask; entry->mask = si->sin_addr.s_addr; } else entry->mask = DEF_ARP_NETMASK; entry->dev = rt->rt_dev; sti(); return 0; } /* * Get an ARP cache entry. */ static int arp_req_get(struct arpreq *req) { struct arpreq r; struct arp_table *entry; struct sockaddr_in *si; /* * We only understand about IP addresses... */ memcpy_fromfs(&r, req, sizeof(r)); if (r.arp_pa.sa_family != AF_INET) return -EPFNOSUPPORT; /* * Is there an existing entry for this address? */ si = (struct sockaddr_in *) &r.arp_pa; cli(); entry = arp_lookup(si->sin_addr.s_addr,PROXY_ANY); if (entry == NULL) { sti(); return -ENXIO; } /* * We found it; copy into structure. */ memcpy(r.arp_ha.sa_data, &entry->ha, entry->hlen); r.arp_ha.sa_family = entry->htype; r.arp_flags = entry->flags; sti(); /* * Copy the information back */ memcpy_tofs(req, &r, sizeof(r)); return 0; } /* * Handle an ARP layer I/O control request. */ int arp_ioctl(unsigned int cmd, void *arg) { struct arpreq r; struct sockaddr_in *si; int err; switch(cmd) { case SIOCDARP: if (!suser()) return -EPERM; err = verify_area(VERIFY_READ, arg, sizeof(struct arpreq)); if(err) return err; memcpy_fromfs(&r, arg, sizeof(r)); if (r.arp_pa.sa_family != AF_INET) return -EPFNOSUPPORT; si = (struct sockaddr_in *) &r.arp_pa; arp_destroy(si->sin_addr.s_addr, 1); return 0; case SIOCGARP: err = verify_area(VERIFY_WRITE, arg, sizeof(struct arpreq)); if(err) return err; return arp_req_get((struct arpreq *)arg); case SIOCSARP: if (!suser()) return -EPERM; err = verify_area(VERIFY_READ, arg, sizeof(struct arpreq)); if(err) return err; return arp_req_set((struct arpreq *)arg); default: return -EINVAL; } /*NOTREACHED*/ return 0; } /* * Called once on startup. */ static struct packet_type arp_packet_type = { 0, /* Should be: __constant_htons(ETH_P_ARP) - but this _doesn't_ come out constant! */ NULL, /* All devices */ arp_rcv, NULL, NULL }; static struct notifier_block arp_dev_notifier={ arp_device_event, NULL, 0 }; void arp_init (void) { /* Register the packet type */ arp_packet_type.type=htons(ETH_P_ARP); dev_add_pack(&arp_packet_type); /* Start with the regular checks for expired arp entries. */ add_timer(&arp_timer); /* Register for device down reports */ register_netdevice_notifier(&arp_dev_notifier); }