--- /dev/null
+/* linux/net/ipv4/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).
+ *
+ * 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
+ * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/capability.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/inetdevice.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/fddidevice.h>
+#include <linux/if_arp.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/slab.h>
+#ifdef CONFIG_SYSCTL
+#include <linux/sysctl.h>
+#endif
+
+#include <net/net_namespace.h>
+#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>
+#include <net/ax25.h>
+#include <net/netrom.h>
+
+#include <linux/uaccess.h>
+
+#include <linux/netfilter_arp.h>
+
+/*
+ * Interface to generic neighbour cache.
+ */
+static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
+static bool arp_key_eq(const struct neighbour *n, const void *pkey);
+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 const 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,
+};
+
+static const 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,
+};
+
+static const struct neigh_ops arp_direct_ops = {
+ .family = AF_INET,
+ .output = neigh_direct_output,
+ .connected_output = neigh_direct_output,
+};
+
+struct neigh_table arp_tbl = {
+ .family = AF_INET,
+ .key_len = 4,
+ .protocol = cpu_to_be16(ETH_P_IP),
+ .hash = arp_hash,
+ .key_eq = arp_key_eq,
+ .constructor = arp_constructor,
+ .proxy_redo = parp_redo,
+ .id = "arp_cache",
+ .parms = {
+ .tbl = &arp_tbl,
+ .reachable_time = 30 * HZ,
+ .data = {
+ [NEIGH_VAR_MCAST_PROBES] = 3,
+ [NEIGH_VAR_UCAST_PROBES] = 3,
+ [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
+ [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
+ [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
+ [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
+ [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
+ [NEIGH_VAR_PROXY_QLEN] = 64,
+ [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
+ [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
+ [NEIGH_VAR_LOCKTIME] = 1 * HZ,
+ },
+ },
+ .gc_interval = 30 * HZ,
+ .gc_thresh1 = 128,
+ .gc_thresh2 = 512,
+ .gc_thresh3 = 1024,
+};
+EXPORT_SYMBOL(arp_tbl);
+
+int arp_mc_map(__be32 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_INFINIBAND:
+ ip_ib_mc_map(addr, dev->broadcast, haddr);
+ return 0;
+ case ARPHRD_IPGRE:
+ ip_ipgre_mc_map(addr, dev->broadcast, 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_rnd)
+{
+ return arp_hashfn(pkey, dev, hash_rnd);
+}
+
+static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
+{
+ return neigh_key_eq32(neigh, pkey);
+}
+
+static int arp_constructor(struct neighbour *neigh)
+{
+ __be32 addr = *(__be32 *)neigh->primary_key;
+ struct net_device *dev = neigh->dev;
+ struct in_device *in_dev;
+ struct neigh_parms *parms;
+
+ rcu_read_lock();
+ in_dev = __in_dev_get_rcu(dev);
+ if (!in_dev) {
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ neigh->type = inet_addr_type(dev_net(dev), addr);
+
+ parms = in_dev->arp_parms;
+ __neigh_parms_put(neigh->parms);
+ neigh->parms = neigh_parms_clone(parms);
+ rcu_read_unlock();
+
+ if (!dev->header_ops) {
+ neigh->nud_state = NUD_NOARP;
+ neigh->ops = &arp_direct_ops;
+ neigh->output = neigh_direct_output;
+ } 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 (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->header_ops->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)
+{
+ __be32 saddr = 0;
+ u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
+ struct net_device *dev = neigh->dev;
+ __be32 target = *(__be32 *)neigh->primary_key;
+ int probes = atomic_read(&neigh->probes);
+ struct in_device *in_dev;
+
+ rcu_read_lock();
+ in_dev = __in_dev_get_rcu(dev);
+ if (!in_dev) {
+ rcu_read_unlock();
+ return;
+ }
+ switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
+ default:
+ case 0: /* By default announce any local IP */
+ if (skb && inet_addr_type(dev_net(dev),
+ ip_hdr(skb)->saddr) == RTN_LOCAL)
+ saddr = ip_hdr(skb)->saddr;
+ break;
+ case 1: /* Restrict announcements of saddr in same subnet */
+ if (!skb)
+ break;
+ saddr = ip_hdr(skb)->saddr;
+ if (inet_addr_type(dev_net(dev), 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;
+ }
+ rcu_read_unlock();
+
+ if (!saddr)
+ saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
+
+ probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
+ if (probes < 0) {
+ if (!(neigh->nud_state & NUD_VALID))
+ pr_debug("trying to ucast probe in NUD_INVALID\n");
+ neigh_ha_snapshot(dst_ha, neigh, dev);
+ dst_hw = dst_ha;
+ } else {
+ probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
+ if (probes < 0) {
+ neigh_app_ns(neigh);
+ return;
+ }
+ }
+
+ arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
+ dst_hw, dev->dev_addr, NULL);
+}
+
+static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
+{
+ struct net *net = dev_net(in_dev->dev);
+ 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;
+ in_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(net, in_dev, sip, tip, scope);
+}
+
+static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
+{
+ struct rtable *rt;
+ int flag = 0;
+ /*unsigned long now; */
+ struct net *net = dev_net(dev);
+
+ rt = ip_route_output(net, sip, tip, 0, 0);
+ if (IS_ERR(rt))
+ return 1;
+ if (rt->dst.dev != dev) {
+ NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
+ flag = 1;
+ }
+ ip_rt_put(rt);
+ return flag;
+}
+
+/*
+ * Check if we can use proxy ARP for this path
+ */
+static inline int arp_fwd_proxy(struct in_device *in_dev,
+ struct net_device *dev, struct rtable *rt)
+{
+ struct in_device *out_dev;
+ int imi, omi = -1;
+
+ if (rt->dst.dev == dev)
+ return 0;
+
+ if (!IN_DEV_PROXY_ARP(in_dev))
+ return 0;
+ imi = IN_DEV_MEDIUM_ID(in_dev);
+ if (imi == 0)
+ return 1;
+ if (imi == -1)
+ return 0;
+
+ /* place to check for proxy_arp for routes */
+
+ out_dev = __in_dev_get_rcu(rt->dst.dev);
+ if (out_dev)
+ omi = IN_DEV_MEDIUM_ID(out_dev);
+
+ return omi != imi && omi != -1;
+}
+
+/*
+ * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
+ *
+ * RFC3069 supports proxy arp replies back to the same interface. This
+ * is done to support (ethernet) switch features, like RFC 3069, where
+ * the individual ports are not allowed to communicate with each
+ * other, BUT they are allowed to talk to the upstream router. As
+ * described in RFC 3069, it is possible to allow these hosts to
+ * communicate through the upstream router, by proxy_arp'ing.
+ *
+ * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
+ *
+ * This technology is known by different names:
+ * In RFC 3069 it is called VLAN Aggregation.
+ * Cisco and Allied Telesyn call it Private VLAN.
+ * Hewlett-Packard call it Source-Port filtering or port-isolation.
+ * Ericsson call it MAC-Forced Forwarding (RFC Draft).
+ *
+ */
+static inline int arp_fwd_pvlan(struct in_device *in_dev,
+ struct net_device *dev, struct rtable *rt,
+ __be32 sip, __be32 tip)
+{
+ /* Private VLAN is only concerned about the same ethernet segment */
+ if (rt->dst.dev != dev)
+ return 0;
+
+ /* Don't reply on self probes (often done by windowz boxes)*/
+ if (sip == tip)
+ return 0;
+
+ if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
+ return 1;
+ else
+ return 0;
+}
+
+/*
+ * Interface to link layer: send routine and receive handler.
+ */
+
+/*
+ * Create an arp packet. If dest_hw is not set, we create a broadcast
+ * message.
+ */
+struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
+ struct net_device *dev, __be32 src_ip,
+ const unsigned char *dest_hw,
+ const unsigned char *src_hw,
+ const unsigned char *target_hw)
+{
+ struct sk_buff *skb;
+ struct arphdr *arp;
+ unsigned char *arp_ptr;
+ int hlen = LL_RESERVED_SPACE(dev);
+ int tlen = dev->needed_tailroom;
+
+ /*
+ * Allocate a buffer
+ */
+
+ skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
+ if (!skb)
+ return NULL;
+
+ skb_reserve(skb, hlen);
+ skb_reset_network_header(skb);
+ arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
+ skb->dev = dev;
+ skb->protocol = htons(ETH_P_ARP);
+ if (!src_hw)
+ src_hw = dev->dev_addr;
+ if (!dest_hw)
+ dest_hw = dev->broadcast;
+
+ /*
+ * Fill the device header for the ARP frame
+ */
+ if (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 IS_ENABLED(CONFIG_AX25)
+ case ARPHRD_AX25:
+ arp->ar_hrd = htons(ARPHRD_AX25);
+ arp->ar_pro = htons(AX25_P_IP);
+ break;
+
+#if IS_ENABLED(CONFIG_NETROM)
+ case ARPHRD_NETROM:
+ arp->ar_hrd = htons(ARPHRD_NETROM);
+ arp->ar_pro = htons(AX25_P_IP);
+ break;
+#endif
+#endif
+
+#if IS_ENABLED(CONFIG_FDDI)
+ case ARPHRD_FDDI:
+ arp->ar_hrd = htons(ARPHRD_ETHER);
+ 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;
+
+ switch (dev->type) {
+#if IS_ENABLED(CONFIG_FIREWIRE_NET)
+ case ARPHRD_IEEE1394:
+ break;
+#endif
+ default:
+ if (target_hw)
+ 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;
+}
+EXPORT_SYMBOL(arp_create);
+
+/*
+ * Send an arp packet.
+ */
+void arp_xmit(struct sk_buff *skb)
+{
+ /* Send it off, maybe filter it using firewalling first. */
+ NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, NULL, skb,
+ NULL, skb->dev, dev_queue_xmit_sk);
+}
+EXPORT_SYMBOL(arp_xmit);
+
+/*
+ * Create and send an arp packet.
+ */
+void arp_send(int type, int ptype, __be32 dest_ip,
+ struct net_device *dev, __be32 src_ip,
+ const unsigned char *dest_hw, const unsigned char *src_hw,
+ const 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)
+ return;
+
+ arp_xmit(skb);
+}
+EXPORT_SYMBOL(arp_send);
+
+/*
+ * Process an arp request.
+ */
+
+static int arp_process(struct sock *sk, struct sk_buff *skb)
+{
+ struct net_device *dev = skb->dev;
+ struct in_device *in_dev = __in_dev_get_rcu(dev);
+ struct arphdr *arp;
+ unsigned char *arp_ptr;
+ struct rtable *rt;
+ unsigned char *sha;
+ __be32 sip, tip;
+ u16 dev_type = dev->type;
+ int addr_type;
+ struct neighbour *n;
+ struct net *net = dev_net(dev);
+ bool is_garp = false;
+
+ /* arp_rcv below verifies the ARP header and verifies the device
+ * is ARP'able.
+ */
+
+ if (!in_dev)
+ goto out;
+
+ arp = arp_hdr(skb);
+
+ switch (dev_type) {
+ default:
+ if (arp->ar_pro != htons(ETH_P_IP) ||
+ htons(dev_type) != arp->ar_hrd)
+ goto out;
+ break;
+ case ARPHRD_ETHER:
+ case ARPHRD_FDDI:
+ case ARPHRD_IEEE802:
+ /*
+ * ETHERNET, 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;
+ case ARPHRD_AX25:
+ if (arp->ar_pro != htons(AX25_P_IP) ||
+ arp->ar_hrd != htons(ARPHRD_AX25))
+ goto out;
+ break;
+ case ARPHRD_NETROM:
+ if (arp->ar_pro != htons(AX25_P_IP) ||
+ arp->ar_hrd != htons(ARPHRD_NETROM))
+ goto out;
+ break;
+ }
+
+ /* 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;
+ switch (dev_type) {
+#if IS_ENABLED(CONFIG_FIREWIRE_NET)
+ case ARPHRD_IEEE1394:
+ break;
+#endif
+ default:
+ 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 (ipv4_is_multicast(tip) ||
+ (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(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(net, tip) == RTN_LOCAL &&
+ !arp_ignore(in_dev, sip, tip))
+ arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
+ dev->dev_addr, sha);
+ goto out;
+ }
+
+ if (arp->ar_op == htons(ARPOP_REQUEST) &&
+ ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
+
+ rt = skb_rtable(skb);
+ addr_type = rt->rt_type;
+
+ if (addr_type == RTN_LOCAL) {
+ int dont_send;
+
+ dont_send = arp_ignore(in_dev, sip, tip);
+ if (!dont_send && IN_DEV_ARPFILTER(in_dev))
+ dont_send = arp_filter(sip, tip, dev);
+ if (!dont_send) {
+ n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
+ if (n) {
+ 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 (addr_type == RTN_UNICAST &&
+ (arp_fwd_proxy(in_dev, dev, rt) ||
+ arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
+ (rt->dst.dev != dev &&
+ pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
+ n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
+ if (n)
+ neigh_release(n);
+
+ if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
+ skb->pkt_type == PACKET_HOST ||
+ NEIGH_VAR(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);
+ return 0;
+ }
+ goto out;
+ }
+ }
+ }
+
+ /* Update our ARP tables */
+
+ n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
+
+ if (IN_DEV_ARP_ACCEPT(in_dev)) {
+ /* Unsolicited ARP is not accepted by default.
+ It is possible, that this option should be enabled for some
+ devices (strip is candidate)
+ */
+ is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
+ inet_addr_type(net, sip) == RTN_UNICAST;
+
+ if (!n &&
+ ((arp->ar_op == htons(ARPOP_REPLY) &&
+ inet_addr_type(net, sip) == RTN_UNICAST) || is_garp))
+ n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
+ }
+
+ 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 +
+ NEIGH_VAR(n->parms, LOCKTIME)) ||
+ is_garp;
+
+ /* 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:
+ consume_skb(skb);
+ return 0;
+}
+
+static void parp_redo(struct sk_buff *skb)
+{
+ arp_process(NULL, skb);
+}
+
+
+/*
+ * Receive an arp request from the device layer.
+ */
+
+static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
+ struct packet_type *pt, struct net_device *orig_dev)
+{
+ const struct arphdr *arp;
+
+ /* do not tweak dropwatch on an ARP we will ignore */
+ if (dev->flags & IFF_NOARP ||
+ skb->pkt_type == PACKET_OTHERHOST ||
+ skb->pkt_type == PACKET_LOOPBACK)
+ goto consumeskb;
+
+ skb = skb_share_check(skb, GFP_ATOMIC);
+ if (!skb)
+ goto out_of_mem;
+
+ /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
+ if (!pskb_may_pull(skb, arp_hdr_len(dev)))
+ goto freeskb;
+
+ arp = arp_hdr(skb);
+ if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
+ goto freeskb;
+
+ memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
+
+ return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, NULL, skb,
+ dev, NULL, arp_process);
+
+consumeskb:
+ consume_skb(skb);
+ return 0;
+freeskb:
+ kfree_skb(skb);
+out_of_mem:
+ return 0;
+}
+
+/*
+ * User level interface (ioctl)
+ */
+
+/*
+ * Set (create) an ARP cache entry.
+ */
+
+static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
+{
+ if (!dev) {
+ IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
+ return 0;
+ }
+ if (__in_dev_get_rtnl(dev)) {
+ IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
+ return 0;
+ }
+ return -ENXIO;
+}
+
+static int arp_req_set_public(struct net *net, struct arpreq *r,
+ struct net_device *dev)
+{
+ __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
+ __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
+
+ if (mask && mask != htonl(0xFFFFFFFF))
+ return -EINVAL;
+ if (!dev && (r->arp_flags & ATF_COM)) {
+ dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
+ r->arp_ha.sa_data);
+ if (!dev)
+ return -ENODEV;
+ }
+ if (mask) {
+ if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
+ return -ENOBUFS;
+ return 0;
+ }
+
+ return arp_req_set_proxy(net, dev, 1);
+}
+
+static int arp_req_set(struct net *net, struct arpreq *r,
+ struct net_device *dev)
+{
+ __be32 ip;
+ struct neighbour *neigh;
+ int err;
+
+ if (r->arp_flags & ATF_PUBL)
+ return arp_req_set_public(net, r, dev);
+
+ ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
+ if (r->arp_flags & ATF_PERM)
+ r->arp_flags |= ATF_COM;
+ if (!dev) {
+ struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
+
+ if (IS_ERR(rt))
+ return PTR_ERR(rt);
+ dev = rt->dst.dev;
+ ip_rt_put(rt);
+ if (!dev)
+ return -EINVAL;
+ }
+ switch (dev->type) {
+#if IS_ENABLED(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 int 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 int arp_state_to_flags(struct neighbour *neigh)
+{
+ if (neigh->nud_state&NUD_PERMANENT)
+ return ATF_PERM | ATF_COM;
+ else if (neigh->nud_state&NUD_VALID)
+ return ATF_COM;
+ else
+ return 0;
+}
+
+/*
+ * Get an ARP cache entry.
+ */
+
+static int arp_req_get(struct arpreq *r, struct net_device *dev)
+{
+ __be32 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_invalidate(struct net_device *dev, __be32 ip)
+{
+ struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
+ int err = -ENXIO;
+
+ 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;
+}
+
+static int arp_req_delete_public(struct net *net, struct arpreq *r,
+ struct net_device *dev)
+{
+ __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
+ __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
+
+ if (mask == htonl(0xFFFFFFFF))
+ return pneigh_delete(&arp_tbl, net, &ip, dev);
+
+ if (mask)
+ return -EINVAL;
+
+ return arp_req_set_proxy(net, dev, 0);
+}
+
+static int arp_req_delete(struct net *net, struct arpreq *r,
+ struct net_device *dev)
+{
+ __be32 ip;
+
+ if (r->arp_flags & ATF_PUBL)
+ return arp_req_delete_public(net, r, dev);
+
+ ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
+ if (!dev) {
+ struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
+ if (IS_ERR(rt))
+ return PTR_ERR(rt);
+ dev = rt->dst.dev;
+ ip_rt_put(rt);
+ if (!dev)
+ return -EINVAL;
+ }
+ return arp_invalidate(dev, ip);
+}
+
+/*
+ * Handle an ARP layer I/O control request.
+ */
+
+int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
+{
+ int err;
+ struct arpreq r;
+ struct net_device *dev = NULL;
+
+ switch (cmd) {
+ case SIOCDARP:
+ case SIOCSARP:
+ if (!ns_capable(net->user_ns, 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;
+ dev = __dev_get_by_name(net, r.arp_dev);
+ if (!dev)
+ 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(net, &r, dev);
+ break;
+ case SIOCSARP:
+ err = arp_req_set(net, &r, dev);
+ break;
+ case SIOCGARP:
+ err = arp_req_get(&r, dev);
+ break;
+ }
+out:
+ rtnl_unlock();
+ if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
+ err = -EFAULT;
+ return err;
+}
+
+static int arp_netdev_event(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct netdev_notifier_change_info *change_info;
+
+ switch (event) {
+ case NETDEV_CHANGEADDR:
+ neigh_changeaddr(&arp_tbl, dev);
+ rt_cache_flush(dev_net(dev));
+ break;
+ case NETDEV_CHANGE:
+ change_info = ptr;
+ if (change_info->flags_changed & IFF_NOARP)
+ neigh_changeaddr(&arp_tbl, dev);
+ 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 __read_mostly = {
+ .type = cpu_to_be16(ETH_P_ARP),
+ .func = arp_rcv,
+};
+
+static int arp_proc_init(void);
+
+void __init arp_init(void)
+{
+ neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
+
+ dev_add_pack(&arp_packet_type);
+ arp_proc_init();
+#ifdef CONFIG_SYSCTL
+ neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
+#endif
+ register_netdevice_notifier(&arp_netdev_notifier);
+}
+
+#ifdef CONFIG_PROC_FS
+#if IS_ENABLED(CONFIG_AX25)
+
+/* ------------------------------------------------------------------------ */
+/*
+ * 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++ = '-';
+ n = (a->ax25_call[6] >> 1) & 0x0F;
+ if (n > 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];
+ 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 IS_ENABLED(CONFIG_AX25)
+ 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++] = hex_asc_hi(n->ha[j]);
+ hbuffer[k++] = hex_asc_lo(n->ha[j]);
+ hbuffer[k++] = ':';
+ }
+ if (k != 0)
+ --k;
+ hbuffer[k] = 0;
+#if IS_ENABLED(CONFIG_AX25)
+ }
+#endif
+ sprintf(tbuf, "%pI4", 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, "%pI4", 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 const 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)
+{
+ return seq_open_net(inode, file, &arp_seq_ops,
+ sizeof(struct neigh_seq_state));
+}
+
+static const struct file_operations arp_seq_fops = {
+ .owner = THIS_MODULE,
+ .open = arp_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release_net,
+};
+
+
+static int __net_init arp_net_init(struct net *net)
+{
+ if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops))
+ return -ENOMEM;
+ return 0;
+}
+
+static void __net_exit arp_net_exit(struct net *net)
+{
+ remove_proc_entry("arp", net->proc_net);
+}
+
+static struct pernet_operations arp_net_ops = {
+ .init = arp_net_init,
+ .exit = arp_net_exit,
+};
+
+static int __init arp_proc_init(void)
+{
+ return register_pernet_subsys(&arp_net_ops);
+}
+
+#else /* CONFIG_PROC_FS */
+
+static int __init arp_proc_init(void)
+{
+ return 0;
+}
+
+#endif /* CONFIG_PROC_FS */
Code Review / kvmfornfv.git / blobdiff