diff options
Diffstat (limited to 'net/ipv4/arp.c')
| -rw-r--r-- | net/ipv4/arp.c | 749 |
1 files changed, 408 insertions, 341 deletions
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 4429b013f269..7f3863daaa40 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* linux/net/ipv4/arp.c * * Copyright (C) 1994 by Florian La Roche @@ -7,11 +8,6 @@ * 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 @@ -113,6 +109,8 @@ #include <net/arp.h> #include <net/ax25.h> #include <net/netrom.h> +#include <net/dst_metadata.h> +#include <net/ip_tunnels.h> #include <linux/uaccess.h> @@ -122,10 +120,12 @@ * 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 int arp_is_multicast(const void *pkey); static const struct neigh_ops arp_generic_ops = { .family = AF_INET, @@ -149,35 +149,33 @@ static const struct neigh_ops arp_direct_ops = { .connected_output = neigh_direct_output, }; -static const 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, -}; - 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, + .is_multicast = arp_is_multicast, .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_bytes = 64*1024, - .ucast_probes = 3, - .mcast_probes = 3, - .anycast_delay = 1 * HZ, - .proxy_delay = (8 * HZ) / 10, - .proxy_qlen = 64, - .locktime = 1 * 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_INTERVAL_PROBE_TIME_MS] = 5 * HZ, + [NEIGH_VAR_GC_STALETIME] = 60 * HZ, + [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_DEFAULT, + [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, @@ -214,24 +212,34 @@ static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd) { - return arp_hashfn(*(u32 *)pkey, dev, *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; + __be32 addr; struct net_device *dev = neigh->dev; struct in_device *in_dev; struct neigh_parms *parms; + u32 inaddr_any = INADDR_ANY; + + if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len); + addr = *(__be32 *)neigh->primary_key; rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); - if (in_dev == NULL) { + if (!in_dev) { rcu_read_unlock(); return -EINVAL; } - neigh->type = inet_addr_type(dev_net(dev), addr); + neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr); parms = in_dev->arp_parms; __neigh_parms_put(neigh->parms); @@ -258,35 +266,6 @@ static int arp_constructor(struct neighbour *neigh) 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 IS_ENABLED(CONFIG_AX25) - case ARPHRD_AX25: -#if IS_ENABLED(CONFIG_NETROM) - case ARPHRD_NETROM: -#endif - neigh->ops = &arp_broken_ops; - neigh->output = neigh->ops->output; - return 0; -#else - break; -#endif - } -#endif if (neigh->type == RTN_MULTICAST) { neigh->nud_state = NUD_NOARP; arp_mc_map(addr, neigh->ha, dev, 1); @@ -315,9 +294,42 @@ static int arp_constructor(struct neighbour *neigh) static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) { dst_link_failure(skb); - kfree_skb(skb); + kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_FAILED); } +/* Create and send an arp packet. */ +static void arp_send_dst(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 dst_entry *dst) +{ + struct sk_buff *skb; + + /* 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; + + skb_dst_set(skb, dst_clone(dst)); + arp_xmit(skb); +} + +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) +{ + arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw, + target_hw, NULL); +} +EXPORT_SYMBOL(arp_send); + static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) { __be32 saddr = 0; @@ -326,6 +338,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) __be32 target = *(__be32 *)neigh->primary_key; int probes = atomic_read(&neigh->probes); struct in_device *in_dev; + struct dst_entry *dst = NULL; rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); @@ -336,7 +349,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { default: case 0: /* By default announce any local IP */ - if (skb && inet_addr_type(dev_net(dev), + if (skb && inet_addr_type_dev_table(dev_net(dev), dev, ip_hdr(skb)->saddr) == RTN_LOCAL) saddr = ip_hdr(skb)->saddr; break; @@ -344,7 +357,8 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) if (!skb) break; saddr = ip_hdr(skb)->saddr; - if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { + if (inet_addr_type_dev_table(dev_net(dev), dev, + saddr) == RTN_LOCAL) { /* saddr should be known to target */ if (inet_addr_onlink(in_dev, target, saddr)) break; @@ -359,28 +373,29 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) if (!saddr) saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); - probes -= neigh->parms->ucast_probes; + probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); if (probes < 0) { - if (!(neigh->nud_state & NUD_VALID)) + if (!(READ_ONCE(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->parms->app_probes; + probes -= NEIGH_VAR(neigh->parms, APP_PROBES); if (probes < 0) { -#ifdef CONFIG_ARPD neigh_app_ns(neigh); -#endif return; } } - arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, - dst_hw, dev->dev_addr, NULL); + if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE)) + dst = skb_dst(skb); + arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, + dst_hw, dev->dev_addr, NULL, dst); } 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)) { @@ -399,6 +414,7 @@ static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) case 3: /* Do not reply for scope host addresses */ sip = 0; scope = RT_SCOPE_LINK; + in_dev = NULL; break; case 4: /* Reserved */ case 5: @@ -410,7 +426,27 @@ static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) default: return 0; } - return !inet_confirm_addr(in_dev, sip, tip, scope); + return !inet_confirm_addr(net, in_dev, sip, tip, scope); +} + +static int arp_accept(struct in_device *in_dev, __be32 sip) +{ + struct net *net = dev_net(in_dev->dev); + int scope = RT_SCOPE_LINK; + + switch (IN_DEV_ARP_ACCEPT(in_dev)) { + case 0: /* Don't create new entries from garp */ + return 0; + case 1: /* Create new entries from garp */ + return 1; + case 2: /* Create a neighbor in the arp table only if sip + * is in the same subnet as an address configured + * on the interface that received the garp message + */ + return !!inet_confirm_addr(net, in_dev, sip, 0, scope); + default: + return 0; + } } static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) @@ -420,82 +456,18 @@ static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) /*unsigned long now; */ struct net *net = dev_net(dev); - rt = ip_route_output(net, sip, tip, 0, 0); + rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev), + RT_SCOPE_UNIVERSE); if (IS_ERR(rt)) return 1; if (rt->dst.dev != dev) { - NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); + __NET_INC_STATS(net, 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, - __be32 paddr, struct net_device *dev) -{ - switch (addr_hint) { - case RTN_LOCAL: - pr_debug("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; - __be32 paddr; - struct neighbour *n; - - if (!skb_dst(skb)) { - pr_debug("arp_find is called with dst==NULL\n"); - kfree_skb(skb); - return 1; - } - - paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr); - if (arp_set_predefined(inet_addr_type(dev_net(dev), 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) { - neigh_ha_snapshot(haddr, n, dev); - neigh_release(n); - return 0; - } - neigh_release(n); - } else - kfree_skb(skb); - return 1; -} -EXPORT_SYMBOL(arp_find); - -/* END OF OBSOLETE FUNCTIONS */ - /* * Check if we can use proxy ARP for this path */ @@ -567,7 +539,7 @@ static inline int arp_fwd_pvlan(struct in_device *in_dev, */ /* - * Create an arp packet. If (dest_hw == NULL), we create a broadcast + * 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, @@ -587,17 +559,17 @@ struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, */ skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); - if (skb == NULL) + if (!skb) return NULL; skb_reserve(skb, hlen); skb_reset_network_header(skb); - arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); + arp = skb_put(skb, arp_hdr_len(dev)); skb->dev = dev; skb->protocol = htons(ETH_P_ARP); - if (src_hw == NULL) + if (!src_hw) src_hw = dev->dev_addr; - if (dest_hw == NULL) + if (!dest_hw) dest_hw = dev->broadcast; /* @@ -661,7 +633,7 @@ struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, break; #endif default: - if (target_hw != NULL) + if (target_hw) memcpy(arp_ptr, target_hw, dev->addr_len); else memset(arp_ptr, 0, dev->addr_len); @@ -677,47 +649,56 @@ out: } EXPORT_SYMBOL(arp_create); +static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + return dev_queue_xmit(skb); +} + /* * Send an arp packet. */ void arp_xmit(struct sk_buff *skb) { + rcu_read_lock(); /* Send it off, maybe filter it using firewalling first. */ - NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); + NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, + dev_net_rcu(skb->dev), NULL, skb, NULL, skb->dev, + arp_xmit_finish); + rcu_read_unlock(); } 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) +static bool arp_is_garp(struct net *net, struct net_device *dev, + int *addr_type, __be16 ar_op, + __be32 sip, __be32 tip, + unsigned char *sha, unsigned char *tha) { - struct sk_buff *skb; + bool is_garp = tip == sip; - /* - * No arp on this interface. + /* Gratuitous ARP _replies_ also require target hwaddr to be + * the same as source. */ - - 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); + if (is_garp && ar_op == htons(ARPOP_REPLY)) + is_garp = + /* IPv4 over IEEE 1394 doesn't provide target + * hardware address field in its ARP payload. + */ + tha && + !memcmp(tha, sha, dev->addr_len); + + if (is_garp) { + *addr_type = inet_addr_type_dev_table(net, dev, sip); + if (*addr_type != RTN_UNICAST) + is_garp = false; + } + return is_garp; } -EXPORT_SYMBOL(arp_send); /* * Process an arp request. */ -static int arp_process(struct sk_buff *skb) +static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) { struct net_device *dev = skb->dev; struct in_device *in_dev = __in_dev_get_rcu(dev); @@ -725,18 +706,20 @@ static int arp_process(struct sk_buff *skb) unsigned char *arp_ptr; struct rtable *rt; unsigned char *sha; + unsigned char *tha = NULL; __be32 sip, tip; u16 dev_type = dev->type; int addr_type; struct neighbour *n; - struct net *net = dev_net(dev); + struct dst_entry *reply_dst = NULL; + bool is_garp = false; /* arp_rcv below verifies the ARP header and verifies the device * is ARP'able. */ - if (in_dev == NULL) - goto out; + if (!in_dev) + goto out_free_skb; arp = arp_hdr(skb); @@ -744,7 +727,7 @@ static int arp_process(struct sk_buff *skb) default: if (arp->ar_pro != htons(ETH_P_IP) || htons(dev_type) != arp->ar_hrd) - goto out; + goto out_free_skb; break; case ARPHRD_ETHER: case ARPHRD_FDDI: @@ -761,17 +744,17 @@ static int arp_process(struct sk_buff *skb) if ((arp->ar_hrd != htons(ARPHRD_ETHER) && arp->ar_hrd != htons(ARPHRD_IEEE802)) || arp->ar_pro != htons(ETH_P_IP)) - goto out; + goto out_free_skb; break; case ARPHRD_AX25: if (arp->ar_pro != htons(AX25_P_IP) || arp->ar_hrd != htons(ARPHRD_AX25)) - goto out; + goto out_free_skb; break; case ARPHRD_NETROM: if (arp->ar_pro != htons(AX25_P_IP) || arp->ar_hrd != htons(ARPHRD_NETROM)) - goto out; + goto out_free_skb; break; } @@ -779,7 +762,7 @@ static int arp_process(struct sk_buff *skb) if (arp->ar_op != htons(ARPOP_REPLY) && arp->ar_op != htons(ARPOP_REQUEST)) - goto out; + goto out_free_skb; /* * Extract fields @@ -795,6 +778,7 @@ static int arp_process(struct sk_buff *skb) break; #endif default: + tha = arp_ptr; arp_ptr += dev->addr_len; } memcpy(&tip, arp_ptr, 4); @@ -804,7 +788,15 @@ static int arp_process(struct sk_buff *skb) */ if (ipv4_is_multicast(tip) || (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) - goto out; + goto out_free_skb; + + /* + * For some 802.11 wireless deployments (and possibly other networks), + * there will be an ARP proxy and gratuitous ARP frames are attacks + * and thus should not be accepted. + */ + if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP)) + goto out_free_skb; /* * Special case: We must set Frame Relay source Q.922 address @@ -829,14 +821,19 @@ static int arp_process(struct sk_buff *skb) * cache. */ + if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb)) + reply_dst = (struct dst_entry *) + iptunnel_metadata_reply(skb_metadata_dst(skb), + GFP_ATOMIC); + /* 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 && + inet_addr_type_dev_table(net, dev, 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; + arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, + sha, dev->dev_addr, sha, reply_dst); + goto out_consume_skb; } if (arp->ar_op == htons(ARPOP_REQUEST) && @@ -854,35 +851,37 @@ static int arp_process(struct sk_buff *skb) 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); + arp_send_dst(ARPOP_REPLY, ETH_P_ARP, + sip, dev, tip, sha, + dev->dev_addr, sha, + reply_dst); neigh_release(n); } } - goto out; + goto out_consume_skb; } 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)))) { + pneigh_lookup(&arp_tbl, net, &tip, dev)))) { 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 || - in_dev->arp_parms->proxy_delay == 0) { - arp_send(ARPOP_REPLY, ETH_P_ARP, sip, - dev, tip, sha, dev->dev_addr, - sha); + NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { + arp_send_dst(ARPOP_REPLY, ETH_P_ARP, + sip, dev, tip, sha, + dev->dev_addr, sha, + reply_dst); } else { pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); - return 0; + goto out_free_dst; } - goto out; + goto out_consume_skb; } } } @@ -891,15 +890,25 @@ static int arp_process(struct sk_buff *skb) n = __neigh_lookup(&arp_tbl, &sip, dev, 0); - if (IN_DEV_ARP_ACCEPT(in_dev)) { + addr_type = -1; + if (n || arp_accept(in_dev, sip)) { + is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op, + sip, tip, sha, tha); + } + + if (arp_accept(in_dev, sip)) { /* 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) || - (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && - inet_addr_type(net, sip) == RTN_UNICAST) + if (!n && + (is_garp || + (arp->ar_op == htons(ARPOP_REPLY) && + (addr_type == RTN_UNICAST || + (addr_type < 0 && + /* postpone calculation to as late as possible */ + inet_addr_type_dev_table(net, dev, sip) == + RTN_UNICAST))))) n = __neigh_lookup(&arp_tbl, &sip, dev, 1); } @@ -912,7 +921,10 @@ static int arp_process(struct sk_buff *skb) agents are active. Taking the first reply prevents arp trashing and chooses the fastest router. */ - override = time_after(jiffies, n->updated + n->parms->locktime); + override = time_after(jiffies, + n->updated + + NEIGH_VAR(n->parms, LOCKTIME)) || + is_garp; /* Broadcast replies and request packets do not assert neighbour reachability. @@ -921,20 +933,31 @@ static int arp_process(struct sk_buff *skb) skb->pkt_type != PACKET_HOST) state = NUD_STALE; neigh_update(n, sha, state, - override ? NEIGH_UPDATE_F_OVERRIDE : 0); + override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0); neigh_release(n); } -out: +out_consume_skb: consume_skb(skb); - return 0; + +out_free_dst: + dst_release(reply_dst); + return NET_RX_SUCCESS; + +out_free_skb: + kfree_skb(skb); + return NET_RX_DROP; } static void parp_redo(struct sk_buff *skb) { - arp_process(skb); + arp_process(dev_net(skb->dev), NULL, skb); } +static int arp_is_multicast(const void *pkey) +{ + return ipv4_is_multicast(*((__be32 *)pkey)); +} /* * Receive an arp request from the device layer. @@ -943,51 +966,110 @@ static void parp_redo(struct sk_buff *skb) static int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) { + enum skb_drop_reason drop_reason; 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 freeskb; + 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))) + drop_reason = pskb_may_pull_reason(skb, arp_hdr_len(dev)); + if (drop_reason != SKB_NOT_DROPPED_YET) goto freeskb; arp = arp_hdr(skb); - if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) + if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) { + drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; goto freeskb; + } memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); - return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); + return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, + dev_net(dev), NULL, skb, dev, NULL, + arp_process); +consumeskb: + consume_skb(skb); + return NET_RX_SUCCESS; freeskb: - kfree_skb(skb); + kfree_skb_reason(skb, drop_reason); out_of_mem: - return 0; + return NET_RX_DROP; } /* * User level interface (ioctl) */ +static struct net_device *arp_req_dev_by_name(struct net *net, struct arpreq *r, + bool getarp) +{ + struct net_device *dev; + + if (getarp) + dev = dev_get_by_name_rcu(net, r->arp_dev); + else + dev = __dev_get_by_name(net, r->arp_dev); + if (!dev) + return ERR_PTR(-ENODEV); + + /* Mmmm... It is wrong... ARPHRD_NETROM == 0 */ + if (!r->arp_ha.sa_family) + r->arp_ha.sa_family = dev->type; + + if ((r->arp_flags & ATF_COM) && r->arp_ha.sa_family != dev->type) + return ERR_PTR(-EINVAL); + + return dev; +} + +static struct net_device *arp_req_dev(struct net *net, struct arpreq *r) +{ + struct net_device *dev; + struct rtable *rt; + __be32 ip; + + if (r->arp_dev[0]) + return arp_req_dev_by_name(net, r, false); + + if (r->arp_flags & ATF_PUBL) + return NULL; + + ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; + + rt = ip_route_output(net, ip, 0, 0, 0, RT_SCOPE_LINK); + if (IS_ERR(rt)) + return ERR_CAST(rt); + + dev = rt->dst.dev; + ip_rt_put(rt); + + if (!dev) + return ERR_PTR(-EINVAL); + + return dev; +} + /* * Set (create) an ARP cache entry. */ static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) { - if (dev == NULL) { + 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); + if (__in_dev_get_rtnl_net(dev)) { + IN_DEV_CONF_SET(__in_dev_get_rtnl_net(dev), PROXY_ARP, on); return 0; } return -ENXIO; @@ -996,49 +1078,37 @@ static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 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, + dev = dev_getbyhwaddr(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) == NULL) - return -ENOBUFS; - return 0; + __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; + + return pneigh_create(&arp_tbl, net, &ip, dev, 0, 0, false); } return arp_req_set_proxy(net, dev, 1); } -static int arp_req_set(struct net *net, struct arpreq *r, - struct net_device *dev) +static int arp_req_set(struct net *net, struct arpreq *r) { - __be32 ip; struct neighbour *neigh; + struct net_device *dev; + __be32 ip; int err; + dev = arp_req_dev(net, r); + if (IS_ERR(dev)) + return PTR_ERR(dev); + 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 == NULL) { - 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: @@ -1060,16 +1130,22 @@ static int arp_req_set(struct net *net, struct arpreq *r, break; } + ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; + 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) + + if (r->arp_flags & ATF_PERM) { + r->arp_flags |= ATF_COM; 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_UPDATE_F_ADMIN, 0); neigh_release(neigh); } return err; @@ -1089,77 +1165,96 @@ static unsigned int arp_state_to_flags(struct neighbour *neigh) * Get an ARP cache entry. */ -static int arp_req_get(struct arpreq *r, struct net_device *dev) +static int arp_req_get(struct net *net, struct arpreq *r) { __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; struct neighbour *neigh; - int err = -ENXIO; + struct net_device *dev; + + if (!r->arp_dev[0]) + return -ENODEV; + + dev = arp_req_dev_by_name(net, r, true); + if (IS_ERR(dev)) + return PTR_ERR(dev); 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)); + if (!neigh) + return -ENXIO; + + if (READ_ONCE(neigh->nud_state) & NUD_NOARP) { neigh_release(neigh); - err = 0; + return -ENXIO; } - return err; + + read_lock_bh(&neigh->lock); + memcpy(r->arp_ha.sa_data, neigh->ha, + min(dev->addr_len, sizeof(r->arp_ha.sa_data))); + r->arp_flags = arp_state_to_flags(neigh); + read_unlock_bh(&neigh->lock); + + neigh_release(neigh); + + r->arp_ha.sa_family = dev->type; + netdev_copy_name(dev, r->arp_dev); + + return 0; } -int arp_invalidate(struct net_device *dev, __be32 ip) +int arp_invalidate(struct net_device *dev, __be32 ip, bool force) { struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); int err = -ENXIO; + struct neigh_table *tbl = &arp_tbl; if (neigh) { - if (neigh->nud_state & ~NUD_NOARP) + if ((READ_ONCE(neigh->nud_state) & NUD_VALID) && !force) { + neigh_release(neigh); + return 0; + } + + if (READ_ONCE(neigh->nud_state) & ~NUD_NOARP) err = neigh_update(neigh, NULL, NUD_FAILED, NEIGH_UPDATE_F_OVERRIDE| - NEIGH_UPDATE_F_ADMIN); + NEIGH_UPDATE_F_ADMIN, 0); + spin_lock_bh(&tbl->lock); neigh_release(neigh); + neigh_remove_one(neigh); + spin_unlock_bh(&tbl->lock); } return err; } -EXPORT_SYMBOL(arp_invalidate); 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) { + __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; - if (mask) - return -EINVAL; + return pneigh_delete(&arp_tbl, net, &ip, dev); + } return arp_req_set_proxy(net, dev, 0); } -static int arp_req_delete(struct net *net, struct arpreq *r, - struct net_device *dev) +static int arp_req_delete(struct net *net, struct arpreq *r) { + struct net_device *dev; __be32 ip; + dev = arp_req_dev(net, r); + if (IS_ERR(dev)) + return PTR_ERR(dev); + 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 == NULL) { - 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); + + return arp_invalidate(dev, ip, true); } /* @@ -1168,15 +1263,16 @@ static int arp_req_delete(struct net *net, struct arpreq *r, int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) { - int err; struct arpreq r; - struct net_device *dev = NULL; + __be32 *netmask; + int err; switch (cmd) { case SIOCDARP: case SIOCSARP: if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; + fallthrough; case SIOCGARP: err = copy_from_user(&r, arg, sizeof(struct arpreq)); if (err) @@ -1192,42 +1288,34 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) if (!(r.arp_flags & ATF_PUBL) && (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) return -EINVAL; + + netmask = &((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr; 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 == 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; - } + *netmask = htonl(0xFFFFFFFFUL); + else if (*netmask && *netmask != htonl(0xFFFFFFFFUL)) + return -EINVAL; switch (cmd) { case SIOCDARP: - err = arp_req_delete(net, &r, dev); + rtnl_net_lock(net); + err = arp_req_delete(net, &r); + rtnl_net_unlock(net); break; case SIOCSARP: - err = arp_req_set(net, &r, dev); + rtnl_net_lock(net); + err = arp_req_set(net, &r); + rtnl_net_unlock(net); break; case SIOCGARP: - err = arp_req_get(&r, dev); + rcu_read_lock(); + err = arp_req_get(net, &r); + rcu_read_unlock(); + + if (!err && copy_to_user(arg, &r, sizeof(r))) + err = -EFAULT; break; } -out: - rtnl_unlock(); - if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) - err = -EFAULT; + return err; } @@ -1236,6 +1324,8 @@ static int arp_netdev_event(struct notifier_block *this, unsigned long event, { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct netdev_notifier_change_info *change_info; + struct in_device *in_dev; + bool evict_nocarrier; switch (event) { case NETDEV_CHANGEADDR: @@ -1246,6 +1336,15 @@ static int arp_netdev_event(struct notifier_block *this, unsigned long event, change_info = ptr; if (change_info->flags_changed & IFF_NOARP) neigh_changeaddr(&arp_tbl, dev); + + in_dev = __in_dev_get_rtnl(dev); + if (!in_dev) + evict_nocarrier = true; + else + evict_nocarrier = IN_DEV_ARP_EVICT_NOCARRIER(in_dev); + + if (evict_nocarrier && !netif_carrier_ok(dev)) + neigh_carrier_down(&arp_tbl, dev); break; default: break; @@ -1277,28 +1376,13 @@ static struct packet_type arp_packet_type __read_mostly = { .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, "ipv4", 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) +static void ax2asc2(ax25_address *a, char *buf) { char c, *s; int n; @@ -1320,10 +1404,10 @@ static char *ax2asc2(ax25_address *a, char *buf) *s++ = n + '0'; *s++ = '\0'; - if (*buf == '\0' || *buf == '-') - return "*"; - - return buf; + if (*buf == '\0' || *buf == '-') { + buf[0] = '*'; + buf[1] = '\0'; + } } #endif /* CONFIG_AX25 */ @@ -1357,7 +1441,7 @@ static void arp_format_neigh_entry(struct seq_file *seq, } #endif sprintf(tbuf, "%pI4", n->primary_key); - seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", + seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n", tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); read_unlock(&n->lock); } @@ -1400,33 +1484,18 @@ static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 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, -}; - +#endif /* CONFIG_PROC_FS */ static int __net_init arp_net_init(struct net *net) { - if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) + if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops, + sizeof(struct neigh_seq_state))) return -ENOMEM; return 0; } @@ -1441,16 +1510,14 @@ static struct pernet_operations arp_net_ops = { .exit = arp_net_exit, }; -static int __init arp_proc_init(void) +void __init arp_init(void) { - return register_pernet_subsys(&arp_net_ops); -} + neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl); -#else /* CONFIG_PROC_FS */ - -static int __init arp_proc_init(void) -{ - return 0; + dev_add_pack(&arp_packet_type); + register_pernet_subsys(&arp_net_ops); +#ifdef CONFIG_SYSCTL + neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); +#endif + register_netdevice_notifier(&arp_netdev_notifier); } - -#endif /* CONFIG_PROC_FS */ |