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/* 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.
*/
#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 = {
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;
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)
{
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;
return hash_val;
}
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);
if (in_dev == NULL)
return -EINVAL;
neigh->type = inet_addr_type(addr);
if (in_dev->arp_parms)
neigh->parms = in_dev->arp_parms;
in_dev_put(in_dev);
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;
u8 *dst_ha = NULL;
struct net_device *dev = neigh->dev;
u32 target = *(u32*)neigh->primary_key;
int probes = atomic_read(&neigh->probes);
if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL)
saddr = skb->nh.iph->saddr;
else
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_filter(__u32 sip, __u32 tip, struct net_device *dev)
{
struct rtable *rt;
int flag = 0;
/*unsigned long now; */
if (ip_route_output(&rt, sip, tip, 0, 0) < 0)
return 1;
if (rt->u.dst.dev != dev) {
NET_INC_STATS_BH(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(
#ifdef CONFIG_ATM_CLIP
dev->type == ARPHRD_ATM ? &clip_tbl :
#endif
&arp_tbl, &nexthop, dev);
if (IS_ERR(n))
return PTR_ERR(n);
dst->neighbour = n;
}
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.
*/
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.
*/
if (dev->flags&IFF_NOARP)
return;
/*
* Allocate a buffer
*/
skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4)
+ dev->hard_header_len + 15, GFP_ATOMIC);
if (skb == NULL)
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);
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 = __constant_htons(ETH_P_IP);
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;
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);
dev_queue_xmit(skb);
return;
out:
kfree_skb(skb);
}
static void parp_redo(struct sk_buff *skb)
{
arp_rcv(skb, skb->dev, NULL);
}
/*
* Receive an arp request by the device layer.
*/
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 ||
arp->ar_pln != 4)
goto out;
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
goto out_of_mem;
if (skb_is_nonlinear(skb)) {
if (skb_linearize(skb, GFP_ATOMIC) != 0)
goto freeskb;
arp = skb->nh.arph;
arp_ptr= (unsigned char *)(arp+1);
}
switch (dev_type) {
default:
if (arp->ar_pro != __constant_htons(ETH_P_IP))
goto out;
if (htons(dev_type) != arp->ar_hrd)
goto out;
break;
#ifdef CONFIG_NET_ETHERNET
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) &&
arp->ar_hrd != __constant_htons(ARPHRD_IEEE802))
goto out;
if (arp->ar_pro != __constant_htons(ETH_P_IP))
goto out;
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
#ifdef CONFIG_NET_FC
case ARPHRD_IEEE802:
/*
* According to RFC 2625, Fibre Channel devices (which are IEEE
* 802 devices) should accept ARP hardware types of 6 (IEEE 802)
* and 1 (Ethernet).
*/
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) &&
arp->ar_op != __constant_htons(ARPOP_REQUEST))
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.
*/
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 == __constant_htons(ARPOP_REQUEST) &&
inet_addr_type(tip) == RTN_LOCAL)
arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr);
goto out;
}
if (arp->ar_op == __constant_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 (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 &&
(IN_DEV_PROXY_ARP(in_dev) || 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 == 0 ||
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 == __constant_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 = 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.
*/
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) ||
skb->pkt_type != PACKET_HOST)
state = NUD_STALE;
neigh_update(n, sha, state, override, 1);
neigh_release(n);
}
out:
if (in_dev)
in_dev_put(in_dev);
freeskb:
kfree_skb(skb);
out_of_mem:
return 0;
}
/*
* User level interface (ioctl, /proc)
*/
/*
* Set (create) an ARP cache entry.
*/
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 rtable * rt;
if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
return err;
dev = rt->u.dst.dev;
ip_rt_put(rt);
if (!dev)
return -EINVAL;
}
if (r->arp_ha.sa_family != dev->type)
return -EINVAL;
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, 1, 0);
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;
strncpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
neigh_release(neigh);
err = 0;
}
return err;
}
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 rtable * rt;
if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 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, 1, 0);
neigh_release(neigh);
}
return err;
}
/*
* Handle an ARP layer I/O control request.
*/
int arp_ioctl(unsigned int cmd, void *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=__constant_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;
}
/*
* 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
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;
for(i=0; i<=NEIGH_HASHMASK; i++) {
struct neighbour *n;
read_lock_bh(&arp_tbl.lock);
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 */
if (!(n->nud_state&~NUD_NOARP))
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
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);
}
read_unlock(&n->lock);
len += size;
pos += size;
if (pos <= offset)
len=0;
if (pos >= offset+length) {
read_unlock_bh(&arp_tbl.lock);
goto done;
}
}
read_unlock_bh(&arp_tbl.lock);
}
for (i=0; i<=PNEIGH_HASHMASK; i++) {
struct pneigh_entry *n;
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;
if (pos <= offset)
len=0;
if (pos >= offset+length)
goto done;
}
}
done:
*start = buffer+len-(pos-offset); /* Start of wanted data */
len = pos-offset; /* Start slop */
if (len>length)
len = length; /* Ending slop */
if (len<0)
len = 0;
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.
*/
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,
data: (void*) 1, /* understand shared skbs */
};
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
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