diff options
Diffstat (limited to 'net/ipv4/arp.c')
| -rw-r--r-- | net/ipv4/arp.c | 1425 |
1 files changed, 1425 insertions, 0 deletions
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c new file mode 100644 index 00000000000..a642fd61285 --- /dev/null +++ b/net/ipv4/arp.c @@ -0,0 +1,1425 @@ +/* linux/net/inet/arp.c + * + * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem 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. + * Krzysztof Halasa: Added Frame Relay ARP support. + * Arnaldo C. Melo : convert /proc/net/arp to seq_file + * Shmulik Hen: Split arp_send to arp_create and + * arp_xmit so intermediate drivers like + * bonding can change the skb before + * sending (e.g. insert 8021q tag). + * Harald Welte : convert to make use of jenkins hash + */ + +#include <linux/module.h> +#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/seq_file.h> +#include <linux/stat.h> +#include <linux/init.h> +#include <linux/net.h> +#include <linux/rcupdate.h> +#include <linux/jhash.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 +#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) +#include <net/atmclip.h> +struct neigh_table *clip_tbl_hook; +#endif + +#include <asm/system.h> +#include <asm/uaccess.h> + +#include <linux/netfilter_arp.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 = { + .family = AF_INET, + .solicit = arp_solicit, + .error_report = arp_error_report, + .output = neigh_resolve_output, + .connected_output = neigh_connected_output, + .hh_output = dev_queue_xmit, + .queue_xmit = dev_queue_xmit, +}; + +static struct neigh_ops arp_hh_ops = { + .family = AF_INET, + .solicit = arp_solicit, + .error_report = arp_error_report, + .output = neigh_resolve_output, + .connected_output = neigh_resolve_output, + .hh_output = dev_queue_xmit, + .queue_xmit = dev_queue_xmit, +}; + +static struct neigh_ops arp_direct_ops = { + .family = AF_INET, + .output = dev_queue_xmit, + .connected_output = dev_queue_xmit, + .hh_output = dev_queue_xmit, + .queue_xmit = dev_queue_xmit, +}; + +struct neigh_ops arp_broken_ops = { + .family = AF_INET, + .solicit = arp_solicit, + .error_report = arp_error_report, + .output = neigh_compat_output, + .connected_output = neigh_compat_output, + .hh_output = dev_queue_xmit, + .queue_xmit = dev_queue_xmit, +}; + +struct neigh_table arp_tbl = { + .family = AF_INET, + .entry_size = sizeof(struct neighbour) + 4, + .key_len = 4, + .hash = arp_hash, + .constructor = arp_constructor, + .proxy_redo = parp_redo, + .id = "arp_cache", + .parms = { + .tbl = &arp_tbl, + .base_reachable_time = 30 * HZ, + .retrans_time = 1 * HZ, + .gc_staletime = 60 * HZ, + .reachable_time = 30 * HZ, + .delay_probe_time = 5 * HZ, + .queue_len = 3, + .ucast_probes = 3, + .mcast_probes = 3, + .anycast_delay = 1 * HZ, + .proxy_delay = (8 * HZ) / 10, + .proxy_qlen = 64, + .locktime = 1 * HZ, + }, + .gc_interval = 30 * HZ, + .gc_thresh1 = 128, + .gc_thresh2 = 512, + .gc_thresh3 = 1024, +}; + +int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir) +{ + switch (dev->type) { + case ARPHRD_ETHER: + case ARPHRD_FDDI: + case ARPHRD_IEEE802: + ip_eth_mc_map(addr, haddr); + return 0; + case ARPHRD_IEEE802_TR: + ip_tr_mc_map(addr, haddr); + return 0; + case ARPHRD_INFINIBAND: + ip_ib_mc_map(addr, haddr); + return 0; + default: + if (dir) { + memcpy(haddr, dev->broadcast, dev->addr_len); + return 0; + } + } + return -EINVAL; +} + + +static u32 arp_hash(const void *pkey, const struct net_device *dev) +{ + return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd); +} + +static int arp_constructor(struct neighbour *neigh) +{ + u32 addr = *(u32*)neigh->primary_key; + struct net_device *dev = neigh->dev; + struct in_device *in_dev; + struct neigh_parms *parms; + + neigh->type = inet_addr_type(addr); + + rcu_read_lock(); + in_dev = rcu_dereference(__in_dev_get(dev)); + if (in_dev == NULL) { + rcu_read_unlock(); + return -EINVAL; + } + + parms = in_dev->arp_parms; + __neigh_parms_put(neigh->parms); + neigh->parms = neigh_parms_clone(parms); + rcu_read_unlock(); + + if (dev->hard_header == NULL) { + neigh->nud_state = NUD_NOARP; + neigh->ops = &arp_direct_ops; + neigh->output = neigh->ops->queue_xmit; + } 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. + */ + switch (dev->type) { + default: + break; + 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 + if (neigh->type == RTN_MULTICAST) { + neigh->nud_state = NUD_NOARP; + arp_mc_map(addr, neigh->ha, dev, 1); + } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { + neigh->nud_state = NUD_NOARP; + memcpy(neigh->ha, dev->dev_addr, dev->addr_len); + } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { + neigh->nud_state = NUD_NOARP; + memcpy(neigh->ha, dev->broadcast, dev->addr_len); + } + if (dev->hard_header_cache) + neigh->ops = &arp_hh_ops; + else + neigh->ops = &arp_generic_ops; + if (neigh->nud_state&NUD_VALID) + neigh->output = neigh->ops->connected_output; + else + neigh->output = neigh->ops->output; + } + return 0; +} + +static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) +{ + dst_link_failure(skb); + kfree_skb(skb); +} + +static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) +{ + u32 saddr = 0; + u8 *dst_ha = NULL; + struct net_device *dev = neigh->dev; + u32 target = *(u32*)neigh->primary_key; + int probes = atomic_read(&neigh->probes); + struct in_device *in_dev = in_dev_get(dev); + + if (!in_dev) + return; + + switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { + default: + case 0: /* By default announce any local IP */ + if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL) + saddr = skb->nh.iph->saddr; + break; + case 1: /* Restrict announcements of saddr in same subnet */ + if (!skb) + break; + saddr = skb->nh.iph->saddr; + if (inet_addr_type(saddr) == RTN_LOCAL) { + /* saddr should be known to target */ + if (inet_addr_onlink(in_dev, target, saddr)) + break; + } + saddr = 0; + break; + case 2: /* Avoid secondary IPs, get a primary/preferred one */ + break; + } + + if (in_dev) + in_dev_put(in_dev); + if (!saddr) + saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); + + if ((probes -= neigh->parms->ucast_probes) < 0) { + if (!(neigh->nud_state&NUD_VALID)) + printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); + dst_ha = neigh->ha; + read_lock_bh(&neigh->lock); + } else if ((probes -= neigh->parms->app_probes) < 0) { +#ifdef CONFIG_ARPD + neigh_app_ns(neigh); +#endif + return; + } + + arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, + dst_ha, dev->dev_addr, NULL); + if (dst_ha) + read_unlock_bh(&neigh->lock); +} + +static int arp_ignore(struct in_device *in_dev, struct net_device *dev, + u32 sip, u32 tip) +{ + int scope; + + switch (IN_DEV_ARP_IGNORE(in_dev)) { + case 0: /* Reply, the tip is already validated */ + return 0; + case 1: /* Reply only if tip is configured on the incoming interface */ + sip = 0; + scope = RT_SCOPE_HOST; + break; + case 2: /* + * Reply only if tip is configured on the incoming interface + * and is in same subnet as sip + */ + scope = RT_SCOPE_HOST; + break; + case 3: /* Do not reply for scope host addresses */ + sip = 0; + scope = RT_SCOPE_LINK; + dev = NULL; + break; + case 4: /* Reserved */ + case 5: + case 6: + case 7: + return 0; + case 8: /* Do not reply */ + return 1; + default: + return 0; + } + return !inet_confirm_addr(dev, sip, tip, scope); +} + +static int arp_filter(__u32 sip, __u32 tip, struct net_device *dev) +{ + struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip, + .saddr = tip } } }; + struct rtable *rt; + int flag = 0; + /*unsigned long now; */ + + if (ip_route_output_key(&rt, &fl) < 0) + return 1; + if (rt->u.dst.dev != dev) { + NET_INC_STATS_BH(LINUX_MIB_ARPFILTER); + flag = 1; + } + ip_rt_put(rt); + return flag; +} + +/* 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 + */ + +static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev) +{ + switch (addr_hint) { + case RTN_LOCAL: + printk(KERN_DEBUG "ARP: arp called for own IP address\n"); + memcpy(haddr, dev->dev_addr, dev->addr_len); + return 1; + case RTN_MULTICAST: + arp_mc_map(paddr, haddr, dev, 1); + return 1; + case RTN_BROADCAST: + memcpy(haddr, dev->broadcast, dev->addr_len); + return 1; + } + return 0; +} + + +int arp_find(unsigned char *haddr, struct sk_buff *skb) +{ + struct net_device *dev = skb->dev; + u32 paddr; + struct neighbour *n; + + if (!skb->dst) { + printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); + kfree_skb(skb); + return 1; + } + + paddr = ((struct rtable*)skb->dst)->rt_gateway; + + if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev)) + return 0; + + n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); + + if (n) { + n->used = jiffies; + if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { + read_lock_bh(&n->lock); + memcpy(haddr, n->ha, dev->addr_len); + read_unlock_bh(&n->lock); + neigh_release(n); + return 0; + } + neigh_release(n); + } else + kfree_skb(skb); + return 1; +} + +/* END OF OBSOLETE FUNCTIONS */ + +int arp_bind_neighbour(struct dst_entry *dst) +{ + struct net_device *dev = dst->dev; + struct neighbour *n = dst->neighbour; + + if (dev == NULL) + return -EINVAL; + if (n == NULL) { + u32 nexthop = ((struct rtable*)dst)->rt_gateway; + if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) + nexthop = 0; + n = __neigh_lookup_errno( +#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) + dev->type == ARPHRD_ATM ? clip_tbl_hook : +#endif + &arp_tbl, &nexthop, dev); + if (IS_ERR(n)) + return PTR_ERR(n); + dst->neighbour = n; + } + return 0; +} + +/* + * Check if we can use proxy ARP for this path + */ + +static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt) +{ + struct in_device *out_dev; + int imi, omi = -1; + + if (!IN_DEV_PROXY_ARP(in_dev)) + return 0; + + if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0) + return 1; + if (imi == -1) + return 0; + + /* place to check for proxy_arp for routes */ + + if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) { + omi = IN_DEV_MEDIUM_ID(out_dev); + in_dev_put(out_dev); + } + return (omi != imi && omi != -1); +} + +/* + * Interface to link layer: send routine and receive handler. + */ + +/* + * Create an arp packet. If (dest_hw == NULL), we create a broadcast + * message. + */ +struct sk_buff *arp_create(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; + + /* + * Allocate a buffer + */ + + skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) + + LL_RESERVED_SPACE(dev), GFP_ATOMIC); + if (skb == NULL) + return NULL; + + skb_reserve(skb, LL_RESERVED_SPACE(dev)); + skb->nh.raw = skb->data; + arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4)); + skb->dev = dev; + skb->protocol = htons(ETH_P_ARP); + if (src_hw == NULL) + src_hw = dev->dev_addr; + if (dest_hw == NULL) + dest_hw = dev->broadcast; + + /* + * Fill the device header for the ARP frame + */ + if (dev->hard_header && + dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0) + 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. + */ + switch (dev->type) { + default: + arp->ar_hrd = htons(dev->type); + arp->ar_pro = htons(ETH_P_IP); + break; + +#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) + case ARPHRD_AX25: + arp->ar_hrd = htons(ARPHRD_AX25); + arp->ar_pro = htons(AX25_P_IP); + break; + +#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) + case ARPHRD_NETROM: + arp->ar_hrd = htons(ARPHRD_NETROM); + arp->ar_pro = htons(AX25_P_IP); + break; +#endif +#endif + +#ifdef CONFIG_FDDI + case ARPHRD_FDDI: + arp->ar_hrd = htons(ARPHRD_ETHER); + arp->ar_pro = htons(ETH_P_IP); + break; +#endif +#ifdef CONFIG_TR + case ARPHRD_IEEE802_TR: + arp->ar_hrd = htons(ARPHRD_IEEE802); + arp->ar_pro = 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; + if (target_hw != NULL) + memcpy(arp_ptr, target_hw, dev->addr_len); + else + memset(arp_ptr, 0, dev->addr_len); + arp_ptr+=dev->addr_len; + memcpy(arp_ptr, &dest_ip, 4); + + return skb; + +out: + kfree_skb(skb); + return NULL; +} + +/* + * Send an arp packet. + */ +void arp_xmit(struct sk_buff *skb) +{ + /* Send it off, maybe filter it using firewalling first. */ + NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); +} + +/* + * Create and send an arp packet. + */ +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; + + /* + * No arp on this interface. + */ + + if (dev->flags&IFF_NOARP) + return; + + skb = arp_create(type, ptype, dest_ip, dev, src_ip, + dest_hw, src_hw, target_hw); + if (skb == NULL) { + return; + } + + arp_xmit(skb); +} + +static void parp_redo(struct sk_buff *skb) +{ + nf_reset(skb); + arp_rcv(skb, skb->dev, NULL); +} + +/* + * Process an arp request. + */ + +static int arp_process(struct sk_buff *skb) +{ + struct net_device *dev = skb->dev; + struct in_device *in_dev = in_dev_get(dev); + struct arphdr *arp; + unsigned char *arp_ptr; + struct rtable *rt; + unsigned char *sha, *tha; + u32 sip, tip; + u16 dev_type = dev->type; + int addr_type; + struct neighbour *n; + + /* arp_rcv below verifies the ARP header and verifies the device + * is ARP'able. + */ + + if (in_dev == NULL) + goto out; + + arp = skb->nh.arph; + + switch (dev_type) { + default: + if (arp->ar_pro != htons(ETH_P_IP) || + htons(dev_type) != arp->ar_hrd) + goto out; + break; +#ifdef CONFIG_NET_ETHERNET + case ARPHRD_ETHER: +#endif +#ifdef CONFIG_TR + case ARPHRD_IEEE802_TR: +#endif +#ifdef CONFIG_FDDI + case ARPHRD_FDDI: +#endif +#ifdef CONFIG_NET_FC + case ARPHRD_IEEE802: +#endif +#if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \ + defined(CONFIG_FDDI) || defined(CONFIG_NET_FC) + /* + * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 + * devices, according to RFC 2625) devices will accept ARP + * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). + * This is the case also of FDDI, where the RFC 1390 says that + * FDDI devices should accept ARP hardware of (1) Ethernet, + * however, to be more robust, we'll accept both 1 (Ethernet) + * or 6 (IEEE 802.2) + */ + if ((arp->ar_hrd != htons(ARPHRD_ETHER) && + arp->ar_hrd != htons(ARPHRD_IEEE802)) || + arp->ar_pro != htons(ETH_P_IP)) + goto out; + break; +#endif +#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) + case ARPHRD_AX25: + if (arp->ar_pro != htons(AX25_P_IP) || + arp->ar_hrd != htons(ARPHRD_AX25)) + goto out; + break; +#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) + case ARPHRD_NETROM: + if (arp->ar_pro != htons(AX25_P_IP) || + arp->ar_hrd != htons(ARPHRD_NETROM)) + goto out; + break; +#endif +#endif + } + + /* Understand only these message types */ + + if (arp->ar_op != htons(ARPOP_REPLY) && + arp->ar_op != htons(ARPOP_REQUEST)) + goto out; + +/* + * Extract fields + */ + arp_ptr= (unsigned char *)(arp+1); + 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. + */ + if (LOOPBACK(tip) || MULTICAST(tip)) + goto out; + +/* + * Special case: We must set Frame Relay source Q.922 address + */ + if (dev_type == ARPHRD_DLCI) + sha = dev->broadcast; + +/* + * 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) */ + if (sip == 0) { + if (arp->ar_op == htons(ARPOP_REQUEST) && + inet_addr_type(tip) == RTN_LOCAL && + !arp_ignore(in_dev,dev,sip,tip)) + arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr); + goto out; + } + + if (arp->ar_op == htons(ARPOP_REQUEST) && + ip_route_input(skb, tip, sip, 0, dev) == 0) { + + rt = (struct rtable*)skb->dst; + addr_type = rt->rt_type; + + if (addr_type == RTN_LOCAL) { + n = neigh_event_ns(&arp_tbl, sha, &sip, dev); + if (n) { + int dont_send = 0; + + if (!dont_send) + dont_send |= arp_ignore(in_dev,dev,sip,tip); + if (!dont_send && IN_DEV_ARPFILTER(in_dev)) + dont_send |= arp_filter(sip,tip,dev); + if (!dont_send) + arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); + + neigh_release(n); + } + goto out; + } else if (IN_DEV_FORWARD(in_dev)) { + if ((rt->rt_flags&RTCF_DNAT) || + (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && + (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) { + n = neigh_event_ns(&arp_tbl, sha, &sip, dev); + if (n) + neigh_release(n); + + if (skb->stamp.tv_sec == LOCALLY_ENQUEUED || + skb->pkt_type == PACKET_HOST || + in_dev->arp_parms->proxy_delay == 0) { + arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); + } else { + pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); + in_dev_put(in_dev); + return 0; + } + 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 == htons(ARPOP_REPLY) && + inet_addr_type(sip) == RTN_UNICAST) + n = __neigh_lookup(&arp_tbl, &sip, dev, -1); +#endif + + if (n) { + int state = NUD_REACHABLE; + int override; + + /* 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. + */ + override = time_after(jiffies, n->updated + n->parms->locktime); + + /* Broadcast replies and request packets + do not assert neighbour reachability. + */ + if (arp->ar_op != htons(ARPOP_REPLY) || + skb->pkt_type != PACKET_HOST) + state = NUD_STALE; + neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0); + neigh_release(n); + } + +out: + if (in_dev) + in_dev_put(in_dev); + kfree_skb(skb); + return 0; +} + + +/* + * Receive an arp request from the device layer. + */ + +int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt) +{ + struct arphdr *arp; + + /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ + if (!pskb_may_pull(skb, (sizeof(struct arphdr) + + (2 * dev->addr_len) + + (2 * sizeof(u32))))) + goto freeskb; + + arp = skb->nh.arph; + if (arp->ar_hln != dev->addr_len || + dev->flags & IFF_NOARP || + skb->pkt_type == PACKET_OTHERHOST || + skb->pkt_type == PACKET_LOOPBACK || + arp->ar_pln != 4) + goto freeskb; + + if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) + goto out_of_mem; + + return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); + +freeskb: + kfree_skb(skb); +out_of_mem: + return 0; +} + +/* + * User level interface (ioctl) + */ + +/* + * Set (create) an ARP cache entry. + */ + +static 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; + + if (r->arp_flags&ATF_PUBL) { + u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; + if (mask && mask != 0xFFFFFFFF) + return -EINVAL; + if (!dev && (r->arp_flags & ATF_COM)) { + dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data); + if (!dev) + return -ENODEV; + } + if (mask) { + if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) + return -ENOBUFS; + return 0; + } + if (dev == NULL) { + ipv4_devconf.proxy_arp = 1; + return 0; + } + if (__in_dev_get(dev)) { + __in_dev_get(dev)->cnf.proxy_arp = 1; + return 0; + } + return -ENXIO; + } + + if (r->arp_flags & ATF_PERM) + r->arp_flags |= ATF_COM; + if (dev == NULL) { + struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, + .tos = RTO_ONLINK } } }; + struct rtable * rt; + if ((err = ip_route_output_key(&rt, &fl)) != 0) + return err; + dev = rt->u.dst.dev; + ip_rt_put(rt); + if (!dev) + return -EINVAL; + } + switch (dev->type) { +#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 (r->arp_ha.sa_family != ARPHRD_FDDI && + r->arp_ha.sa_family != ARPHRD_ETHER && + r->arp_ha.sa_family != ARPHRD_IEEE802) + return -EINVAL; + break; +#endif + default: + if (r->arp_ha.sa_family != dev->type) + return -EINVAL; + break; + } + + neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); + err = PTR_ERR(neigh); + if (!IS_ERR(neigh)) { + unsigned state = NUD_STALE; + 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, + NEIGH_UPDATE_F_OVERRIDE| + NEIGH_UPDATE_F_ADMIN); + neigh_release(neigh); + } + return err; +} + +static unsigned arp_state_to_flags(struct neighbour *neigh) +{ + unsigned flags = 0; + if (neigh->nud_state&NUD_PERMANENT) + flags = ATF_PERM|ATF_COM; + else if (neigh->nud_state&NUD_VALID) + flags = ATF_COM; + return flags; +} + +/* + * Get an ARP cache entry. + */ + +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); + if (neigh) { + read_lock_bh(&neigh->lock); + memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); + r->arp_flags = arp_state_to_flags(neigh); + read_unlock_bh(&neigh->lock); + r->arp_ha.sa_family = dev->type; + strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); + neigh_release(neigh); + err = 0; + } + return err; +} + +static 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; + + if (r->arp_flags & ATF_PUBL) { + u32 mask = + ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; + if (mask == 0xFFFFFFFF) + return pneigh_delete(&arp_tbl, &ip, dev); + if (mask == 0) { + if (dev == NULL) { + ipv4_devconf.proxy_arp = 0; + return 0; + } + if (__in_dev_get(dev)) { + __in_dev_get(dev)->cnf.proxy_arp = 0; + return 0; + } + return -ENXIO; + } + return -EINVAL; + } + + if (dev == NULL) { + struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, + .tos = RTO_ONLINK } } }; + struct rtable * rt; + if ((err = ip_route_output_key(&rt, &fl)) != 0) + return err; + dev = rt->u.dst.dev; + ip_rt_put(rt); + if (!dev) + return -EINVAL; + } + err = -ENXIO; + neigh = neigh_lookup(&arp_tbl, &ip, dev); + if (neigh) { + if (neigh->nud_state&~NUD_NOARP) + err = neigh_update(neigh, NULL, NUD_FAILED, + NEIGH_UPDATE_F_OVERRIDE| + NEIGH_UPDATE_F_ADMIN); + neigh_release(neigh); + } + return err; +} + +/* + * Handle an ARP layer I/O control request. + */ + +int arp_ioctl(unsigned int cmd, void __user *arg) +{ + int err; + struct arpreq r; + struct net_device *dev = NULL; + + switch (cmd) { + case SIOCDARP: + case SIOCSARP: + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + case SIOCGARP: + err = copy_from_user(&r, arg, sizeof(struct arpreq)); + if (err) + return -EFAULT; + break; + default: + return -EINVAL; + } + + if (r.arp_pa.sa_family != AF_INET) + return -EPFNOSUPPORT; + + if (!(r.arp_flags & ATF_PUBL) && + (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) + return -EINVAL; + if (!(r.arp_flags & ATF_NETMASK)) + ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = + htonl(0xFFFFFFFFUL); + rtnl_lock(); + if (r.arp_dev[0]) { + err = -ENODEV; + if ((dev = __dev_get_by_name(r.arp_dev)) == NULL) + goto out; + + /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ + if (!r.arp_ha.sa_family) + r.arp_ha.sa_family = dev->type; + err = -EINVAL; + if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) + goto out; + } else if (cmd == SIOCGARP) { + err = -ENODEV; + goto out; + } + + switch(cmd) { + case SIOCDARP: + err = arp_req_delete(&r, dev); + break; + case SIOCSARP: + err = arp_req_set(&r, dev); + break; + case SIOCGARP: + err = arp_req_get(&r, dev); + if (!err && copy_to_user(arg, &r, sizeof(r))) + err = -EFAULT; + break; + } +out: + rtnl_unlock(); + return err; +} + +static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) +{ + struct net_device *dev = ptr; + + switch (event) { + case NETDEV_CHANGEADDR: + neigh_changeaddr(&arp_tbl, dev); + rt_cache_flush(0); + break; + default: + break; + } + + return NOTIFY_DONE; +} + +static struct notifier_block arp_netdev_notifier = { + .notifier_call = arp_netdev_event, +}; + +/* Note, that it is not on notifier chain. + It is necessary, that this routine was called after route cache will be + flushed. + */ +void arp_ifdown(struct net_device *dev) +{ + neigh_ifdown(&arp_tbl, dev); +} + + +/* + * Called once on startup. + */ + +static struct packet_type arp_packet_type = { + .type = __constant_htons(ETH_P_ARP), + .func = arp_rcv, +}; + +static int arp_proc_init(void); + +void __init arp_init(void) +{ + neigh_table_init(&arp_tbl); + + dev_add_pack(&arp_packet_type); + arp_proc_init(); +#ifdef CONFIG_SYSCTL + neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, + NET_IPV4_NEIGH, "ipv4", NULL, NULL); +#endif + register_netdevice_notifier(&arp_netdev_notifier); +} + +#ifdef CONFIG_PROC_FS +#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) + +/* ------------------------------------------------------------------------ */ +/* + * ax25 -> ASCII conversion + */ +static 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 /* CONFIG_AX25 */ + +#define HBUFFERLEN 30 + +static void arp_format_neigh_entry(struct seq_file *seq, + struct neighbour *n) +{ + char hbuffer[HBUFFERLEN]; + const char hexbuf[] = "0123456789ABCDEF"; + int k, j; + char tbuf[16]; + struct net_device *dev = n->dev; + int hatype = dev->type; + + 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 + 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 + sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); + seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", + tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); + read_unlock(&n->lock); +} + +static void arp_format_pneigh_entry(struct seq_file *seq, + struct pneigh_entry *n) +{ + 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)); + seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", + tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", + dev ? dev->name : "*"); +} + +static int arp_seq_show(struct seq_file *seq, void *v) +{ + if (v == SEQ_START_TOKEN) { + seq_puts(seq, "IP address HW type Flags " + "HW address Mask Device\n"); + } else { + struct neigh_seq_state *state = seq->private; + + if (state->flags & NEIGH_SEQ_IS_PNEIGH) + arp_format_pneigh_entry(seq, v); + else + arp_format_neigh_entry(seq, v); + } + + return 0; +} + +static void *arp_seq_start(struct seq_file *seq, loff_t *pos) +{ + /* Don't want to confuse "arp -a" w/ magic entries, + * so we tell the generic iterator to skip NUD_NOARP. + */ + return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); +} + +/* ------------------------------------------------------------------------ */ + +static struct seq_operations arp_seq_ops = { + .start = arp_seq_start, + .next = neigh_seq_next, + .stop = neigh_seq_stop, + .show = arp_seq_show, +}; + +static int arp_seq_open(struct inode *inode, struct file *file) +{ + struct seq_file *seq; + int rc = -ENOMEM; + struct neigh_seq_state *s = kmalloc(sizeof(*s), GFP_KERNEL); + + if (!s) + goto out; + + memset(s, 0, sizeof(*s)); + rc = seq_open(file, &arp_seq_ops); + if (rc) + goto out_kfree; + + seq = file->private_data; + seq->private = s; +out: + return rc; +out_kfree: + kfree(s); + goto out; +} + +static struct file_operations arp_seq_fops = { + .owner = THIS_MODULE, + .open = arp_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; + +static int __init arp_proc_init(void) +{ + if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops)) + return -ENOMEM; + return 0; +} + +#else /* CONFIG_PROC_FS */ + +static int __init arp_proc_init(void) +{ + return 0; +} + +#endif /* CONFIG_PROC_FS */ + +EXPORT_SYMBOL(arp_broken_ops); +EXPORT_SYMBOL(arp_find); +EXPORT_SYMBOL(arp_rcv); +EXPORT_SYMBOL(arp_create); +EXPORT_SYMBOL(arp_xmit); +EXPORT_SYMBOL(arp_send); +EXPORT_SYMBOL(arp_tbl); + +#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) +EXPORT_SYMBOL(clip_tbl_hook); +#endif |