1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384138513861387138813891390139113921393139413951396139713981399140014011402140314041405140614071408140914101411141214131414141514161417141814191420142114221423142414251426142714281429143014311432143314341435143614371438143914401441144214431444144514461447144814491450145114521453145414551456145714581459146014611462146314641465146614671468146914701471147214731474147514761477147814791480148114821483148414851486148714881489149014911492149314941495149614971498149915001501150215031504150515061507 |
- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * NET3: Implementation of the ICMP protocol layer.
- *
- * Alan Cox, <[email protected]>
- *
- * Some of the function names and the icmp unreach table for this
- * module were derived from [icmp.c 1.0.11 06/02/93] by
- * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
- * Other than that this module is a complete rewrite.
- *
- * Fixes:
- * Clemens Fruhwirth : introduce global icmp rate limiting
- * with icmp type masking ability instead
- * of broken per type icmp timeouts.
- * Mike Shaver : RFC1122 checks.
- * Alan Cox : Multicast ping reply as self.
- * Alan Cox : Fix atomicity lockup in ip_build_xmit
- * call.
- * Alan Cox : Added 216,128 byte paths to the MTU
- * code.
- * Martin Mares : RFC1812 checks.
- * Martin Mares : Can be configured to follow redirects
- * if acting as a router _without_ a
- * routing protocol (RFC 1812).
- * Martin Mares : Echo requests may be configured to
- * be ignored (RFC 1812).
- * Martin Mares : Limitation of ICMP error message
- * transmit rate (RFC 1812).
- * Martin Mares : TOS and Precedence set correctly
- * (RFC 1812).
- * Martin Mares : Now copying as much data from the
- * original packet as we can without
- * exceeding 576 bytes (RFC 1812).
- * Willy Konynenberg : Transparent proxying support.
- * Keith Owens : RFC1191 correction for 4.2BSD based
- * path MTU bug.
- * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
- * valid (RFC 1812).
- * Andi Kleen : Check all packet lengths properly
- * and moved all kfree_skb() up to
- * icmp_rcv.
- * Andi Kleen : Move the rate limit bookkeeping
- * into the dest entry and use a token
- * bucket filter (thanks to ANK). Make
- * the rates sysctl configurable.
- * Yu Tianli : Fixed two ugly bugs in icmp_send
- * - IP option length was accounted wrongly
- * - ICMP header length was not accounted
- * at all.
- * Tristan Greaves : Added sysctl option to ignore bogus
- * broadcast responses from broken routers.
- *
- * To Fix:
- *
- * - Should use skb_pull() instead of all the manual checking.
- * This would also greatly simply some upper layer error handlers. --AK
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/module.h>
- #include <linux/types.h>
- #include <linux/jiffies.h>
- #include <linux/kernel.h>
- #include <linux/fcntl.h>
- #include <linux/socket.h>
- #include <linux/in.h>
- #include <linux/inet.h>
- #include <linux/inetdevice.h>
- #include <linux/netdevice.h>
- #include <linux/string.h>
- #include <linux/netfilter_ipv4.h>
- #include <linux/slab.h>
- #include <net/snmp.h>
- #include <net/ip.h>
- #include <net/route.h>
- #include <net/protocol.h>
- #include <net/icmp.h>
- #include <net/tcp.h>
- #include <net/udp.h>
- #include <net/raw.h>
- #include <net/ping.h>
- #include <linux/skbuff.h>
- #include <net/sock.h>
- #include <linux/errno.h>
- #include <linux/timer.h>
- #include <linux/init.h>
- #include <linux/uaccess.h>
- #include <net/checksum.h>
- #include <net/xfrm.h>
- #include <net/inet_common.h>
- #include <net/ip_fib.h>
- #include <net/l3mdev.h>
- /*
- * Build xmit assembly blocks
- */
- struct icmp_bxm {
- struct sk_buff *skb;
- int offset;
- int data_len;
- struct {
- struct icmphdr icmph;
- __be32 times[3];
- } data;
- int head_len;
- struct ip_options_data replyopts;
- };
- /* An array of errno for error messages from dest unreach. */
- /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
- const struct icmp_err icmp_err_convert[] = {
- {
- .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
- .fatal = 0,
- },
- {
- .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
- .fatal = 0,
- },
- {
- .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
- .fatal = 1,
- },
- {
- .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
- .fatal = 1,
- },
- {
- .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
- .fatal = 0,
- },
- {
- .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
- .fatal = 0,
- },
- {
- .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
- .fatal = 1,
- },
- {
- .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
- .fatal = 1,
- },
- {
- .errno = ENONET, /* ICMP_HOST_ISOLATED */
- .fatal = 1,
- },
- {
- .errno = ENETUNREACH, /* ICMP_NET_ANO */
- .fatal = 1,
- },
- {
- .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
- .fatal = 1,
- },
- {
- .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
- .fatal = 0,
- },
- {
- .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
- .fatal = 0,
- },
- {
- .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
- .fatal = 1,
- },
- {
- .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
- .fatal = 1,
- },
- {
- .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
- .fatal = 1,
- },
- };
- EXPORT_SYMBOL(icmp_err_convert);
- /*
- * ICMP control array. This specifies what to do with each ICMP.
- */
- struct icmp_control {
- enum skb_drop_reason (*handler)(struct sk_buff *skb);
- short error; /* This ICMP is classed as an error message */
- };
- static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
- static DEFINE_PER_CPU(struct sock *, ipv4_icmp_sk);
- /* Called with BH disabled */
- static inline struct sock *icmp_xmit_lock(struct net *net)
- {
- struct sock *sk;
- sk = this_cpu_read(ipv4_icmp_sk);
- if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
- /* This can happen if the output path signals a
- * dst_link_failure() for an outgoing ICMP packet.
- */
- return NULL;
- }
- sock_net_set(sk, net);
- return sk;
- }
- static inline void icmp_xmit_unlock(struct sock *sk)
- {
- sock_net_set(sk, &init_net);
- spin_unlock(&sk->sk_lock.slock);
- }
- int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
- int sysctl_icmp_msgs_burst __read_mostly = 50;
- static struct {
- spinlock_t lock;
- u32 credit;
- u32 stamp;
- } icmp_global = {
- .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock),
- };
- /**
- * icmp_global_allow - Are we allowed to send one more ICMP message ?
- *
- * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec.
- * Returns false if we reached the limit and can not send another packet.
- * Note: called with BH disabled
- */
- bool icmp_global_allow(void)
- {
- u32 credit, delta, incr = 0, now = (u32)jiffies;
- bool rc = false;
- /* Check if token bucket is empty and cannot be refilled
- * without taking the spinlock. The READ_ONCE() are paired
- * with the following WRITE_ONCE() in this same function.
- */
- if (!READ_ONCE(icmp_global.credit)) {
- delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ);
- if (delta < HZ / 50)
- return false;
- }
- spin_lock(&icmp_global.lock);
- delta = min_t(u32, now - icmp_global.stamp, HZ);
- if (delta >= HZ / 50) {
- incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ;
- if (incr)
- WRITE_ONCE(icmp_global.stamp, now);
- }
- credit = min_t(u32, icmp_global.credit + incr,
- READ_ONCE(sysctl_icmp_msgs_burst));
- if (credit) {
- /* We want to use a credit of one in average, but need to randomize
- * it for security reasons.
- */
- credit = max_t(int, credit - prandom_u32_max(3), 0);
- rc = true;
- }
- WRITE_ONCE(icmp_global.credit, credit);
- spin_unlock(&icmp_global.lock);
- return rc;
- }
- EXPORT_SYMBOL(icmp_global_allow);
- static bool icmpv4_mask_allow(struct net *net, int type, int code)
- {
- if (type > NR_ICMP_TYPES)
- return true;
- /* Don't limit PMTU discovery. */
- if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
- return true;
- /* Limit if icmp type is enabled in ratemask. */
- if (!((1 << type) & READ_ONCE(net->ipv4.sysctl_icmp_ratemask)))
- return true;
- return false;
- }
- static bool icmpv4_global_allow(struct net *net, int type, int code)
- {
- if (icmpv4_mask_allow(net, type, code))
- return true;
- if (icmp_global_allow())
- return true;
- return false;
- }
- /*
- * Send an ICMP frame.
- */
- static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
- struct flowi4 *fl4, int type, int code)
- {
- struct dst_entry *dst = &rt->dst;
- struct inet_peer *peer;
- bool rc = true;
- int vif;
- if (icmpv4_mask_allow(net, type, code))
- goto out;
- /* No rate limit on loopback */
- if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
- goto out;
- vif = l3mdev_master_ifindex(dst->dev);
- peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
- rc = inet_peer_xrlim_allow(peer,
- READ_ONCE(net->ipv4.sysctl_icmp_ratelimit));
- if (peer)
- inet_putpeer(peer);
- out:
- return rc;
- }
- /*
- * Maintain the counters used in the SNMP statistics for outgoing ICMP
- */
- void icmp_out_count(struct net *net, unsigned char type)
- {
- ICMPMSGOUT_INC_STATS(net, type);
- ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
- }
- /*
- * Checksum each fragment, and on the first include the headers and final
- * checksum.
- */
- static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
- struct sk_buff *skb)
- {
- struct icmp_bxm *icmp_param = from;
- __wsum csum;
- csum = skb_copy_and_csum_bits(icmp_param->skb,
- icmp_param->offset + offset,
- to, len);
- skb->csum = csum_block_add(skb->csum, csum, odd);
- if (icmp_pointers[icmp_param->data.icmph.type].error)
- nf_ct_attach(skb, icmp_param->skb);
- return 0;
- }
- static void icmp_push_reply(struct sock *sk,
- struct icmp_bxm *icmp_param,
- struct flowi4 *fl4,
- struct ipcm_cookie *ipc, struct rtable **rt)
- {
- struct sk_buff *skb;
- if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
- icmp_param->data_len+icmp_param->head_len,
- icmp_param->head_len,
- ipc, rt, MSG_DONTWAIT) < 0) {
- __ICMP_INC_STATS(sock_net(sk), ICMP_MIB_OUTERRORS);
- ip_flush_pending_frames(sk);
- } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
- struct icmphdr *icmph = icmp_hdr(skb);
- __wsum csum;
- struct sk_buff *skb1;
- csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
- (char *)icmph,
- icmp_param->head_len);
- skb_queue_walk(&sk->sk_write_queue, skb1) {
- csum = csum_add(csum, skb1->csum);
- }
- icmph->checksum = csum_fold(csum);
- skb->ip_summed = CHECKSUM_NONE;
- ip_push_pending_frames(sk, fl4);
- }
- }
- /*
- * Driving logic for building and sending ICMP messages.
- */
- static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
- {
- struct ipcm_cookie ipc;
- struct rtable *rt = skb_rtable(skb);
- struct net *net = dev_net(rt->dst.dev);
- struct flowi4 fl4;
- struct sock *sk;
- struct inet_sock *inet;
- __be32 daddr, saddr;
- u32 mark = IP4_REPLY_MARK(net, skb->mark);
- int type = icmp_param->data.icmph.type;
- int code = icmp_param->data.icmph.code;
- if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb))
- return;
- /* Needed by both icmp_global_allow and icmp_xmit_lock */
- local_bh_disable();
- /* global icmp_msgs_per_sec */
- if (!icmpv4_global_allow(net, type, code))
- goto out_bh_enable;
- sk = icmp_xmit_lock(net);
- if (!sk)
- goto out_bh_enable;
- inet = inet_sk(sk);
- icmp_param->data.icmph.checksum = 0;
- ipcm_init(&ipc);
- inet->tos = ip_hdr(skb)->tos;
- ipc.sockc.mark = mark;
- daddr = ipc.addr = ip_hdr(skb)->saddr;
- saddr = fib_compute_spec_dst(skb);
- if (icmp_param->replyopts.opt.opt.optlen) {
- ipc.opt = &icmp_param->replyopts.opt;
- if (ipc.opt->opt.srr)
- daddr = icmp_param->replyopts.opt.opt.faddr;
- }
- memset(&fl4, 0, sizeof(fl4));
- fl4.daddr = daddr;
- fl4.saddr = saddr;
- fl4.flowi4_mark = mark;
- fl4.flowi4_uid = sock_net_uid(net, NULL);
- fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
- fl4.flowi4_proto = IPPROTO_ICMP;
- fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev);
- security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4));
- rt = ip_route_output_key(net, &fl4);
- if (IS_ERR(rt))
- goto out_unlock;
- if (icmpv4_xrlim_allow(net, rt, &fl4, type, code))
- icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt);
- ip_rt_put(rt);
- out_unlock:
- icmp_xmit_unlock(sk);
- out_bh_enable:
- local_bh_enable();
- }
- /*
- * The device used for looking up which routing table to use for sending an ICMP
- * error is preferably the source whenever it is set, which should ensure the
- * icmp error can be sent to the source host, else lookup using the routing
- * table of the destination device, else use the main routing table (index 0).
- */
- static struct net_device *icmp_get_route_lookup_dev(struct sk_buff *skb)
- {
- struct net_device *route_lookup_dev = NULL;
- if (skb->dev)
- route_lookup_dev = skb->dev;
- else if (skb_dst(skb))
- route_lookup_dev = skb_dst(skb)->dev;
- return route_lookup_dev;
- }
- static struct rtable *icmp_route_lookup(struct net *net,
- struct flowi4 *fl4,
- struct sk_buff *skb_in,
- const struct iphdr *iph,
- __be32 saddr, u8 tos, u32 mark,
- int type, int code,
- struct icmp_bxm *param)
- {
- struct net_device *route_lookup_dev;
- struct rtable *rt, *rt2;
- struct flowi4 fl4_dec;
- int err;
- memset(fl4, 0, sizeof(*fl4));
- fl4->daddr = (param->replyopts.opt.opt.srr ?
- param->replyopts.opt.opt.faddr : iph->saddr);
- fl4->saddr = saddr;
- fl4->flowi4_mark = mark;
- fl4->flowi4_uid = sock_net_uid(net, NULL);
- fl4->flowi4_tos = RT_TOS(tos);
- fl4->flowi4_proto = IPPROTO_ICMP;
- fl4->fl4_icmp_type = type;
- fl4->fl4_icmp_code = code;
- route_lookup_dev = icmp_get_route_lookup_dev(skb_in);
- fl4->flowi4_oif = l3mdev_master_ifindex(route_lookup_dev);
- security_skb_classify_flow(skb_in, flowi4_to_flowi_common(fl4));
- rt = ip_route_output_key_hash(net, fl4, skb_in);
- if (IS_ERR(rt))
- return rt;
- /* No need to clone since we're just using its address. */
- rt2 = rt;
- rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
- flowi4_to_flowi(fl4), NULL, 0);
- if (!IS_ERR(rt)) {
- if (rt != rt2)
- return rt;
- } else if (PTR_ERR(rt) == -EPERM) {
- rt = NULL;
- } else
- return rt;
- err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
- if (err)
- goto relookup_failed;
- if (inet_addr_type_dev_table(net, route_lookup_dev,
- fl4_dec.saddr) == RTN_LOCAL) {
- rt2 = __ip_route_output_key(net, &fl4_dec);
- if (IS_ERR(rt2))
- err = PTR_ERR(rt2);
- } else {
- struct flowi4 fl4_2 = {};
- unsigned long orefdst;
- fl4_2.daddr = fl4_dec.saddr;
- rt2 = ip_route_output_key(net, &fl4_2);
- if (IS_ERR(rt2)) {
- err = PTR_ERR(rt2);
- goto relookup_failed;
- }
- /* Ugh! */
- orefdst = skb_in->_skb_refdst; /* save old refdst */
- skb_dst_set(skb_in, NULL);
- err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
- RT_TOS(tos), rt2->dst.dev);
- dst_release(&rt2->dst);
- rt2 = skb_rtable(skb_in);
- skb_in->_skb_refdst = orefdst; /* restore old refdst */
- }
- if (err)
- goto relookup_failed;
- rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst,
- flowi4_to_flowi(&fl4_dec), NULL,
- XFRM_LOOKUP_ICMP);
- if (!IS_ERR(rt2)) {
- dst_release(&rt->dst);
- memcpy(fl4, &fl4_dec, sizeof(*fl4));
- rt = rt2;
- } else if (PTR_ERR(rt2) == -EPERM) {
- if (rt)
- dst_release(&rt->dst);
- return rt2;
- } else {
- err = PTR_ERR(rt2);
- goto relookup_failed;
- }
- return rt;
- relookup_failed:
- if (rt)
- return rt;
- return ERR_PTR(err);
- }
- /*
- * Send an ICMP message in response to a situation
- *
- * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
- * MAY send more (we do).
- * MUST NOT change this header information.
- * MUST NOT reply to a multicast/broadcast IP address.
- * MUST NOT reply to a multicast/broadcast MAC address.
- * MUST reply to only the first fragment.
- */
- void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
- const struct ip_options *opt)
- {
- struct iphdr *iph;
- int room;
- struct icmp_bxm icmp_param;
- struct rtable *rt = skb_rtable(skb_in);
- struct ipcm_cookie ipc;
- struct flowi4 fl4;
- __be32 saddr;
- u8 tos;
- u32 mark;
- struct net *net;
- struct sock *sk;
- if (!rt)
- goto out;
- if (rt->dst.dev)
- net = dev_net(rt->dst.dev);
- else if (skb_in->dev)
- net = dev_net(skb_in->dev);
- else
- goto out;
- /*
- * Find the original header. It is expected to be valid, of course.
- * Check this, icmp_send is called from the most obscure devices
- * sometimes.
- */
- iph = ip_hdr(skb_in);
- if ((u8 *)iph < skb_in->head ||
- (skb_network_header(skb_in) + sizeof(*iph)) >
- skb_tail_pointer(skb_in))
- goto out;
- /*
- * No replies to physical multicast/broadcast
- */
- if (skb_in->pkt_type != PACKET_HOST)
- goto out;
- /*
- * Now check at the protocol level
- */
- if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
- goto out;
- /*
- * Only reply to fragment 0. We byte re-order the constant
- * mask for efficiency.
- */
- if (iph->frag_off & htons(IP_OFFSET))
- goto out;
- /*
- * If we send an ICMP error to an ICMP error a mess would result..
- */
- if (icmp_pointers[type].error) {
- /*
- * We are an error, check if we are replying to an
- * ICMP error
- */
- if (iph->protocol == IPPROTO_ICMP) {
- u8 _inner_type, *itp;
- itp = skb_header_pointer(skb_in,
- skb_network_header(skb_in) +
- (iph->ihl << 2) +
- offsetof(struct icmphdr,
- type) -
- skb_in->data,
- sizeof(_inner_type),
- &_inner_type);
- if (!itp)
- goto out;
- /*
- * Assume any unknown ICMP type is an error. This
- * isn't specified by the RFC, but think about it..
- */
- if (*itp > NR_ICMP_TYPES ||
- icmp_pointers[*itp].error)
- goto out;
- }
- }
- /* Needed by both icmp_global_allow and icmp_xmit_lock */
- local_bh_disable();
- /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless
- * incoming dev is loopback. If outgoing dev change to not be
- * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow)
- */
- if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) &&
- !icmpv4_global_allow(net, type, code))
- goto out_bh_enable;
- sk = icmp_xmit_lock(net);
- if (!sk)
- goto out_bh_enable;
- /*
- * Construct source address and options.
- */
- saddr = iph->daddr;
- if (!(rt->rt_flags & RTCF_LOCAL)) {
- struct net_device *dev = NULL;
- rcu_read_lock();
- if (rt_is_input_route(rt) &&
- READ_ONCE(net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr))
- dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
- if (dev)
- saddr = inet_select_addr(dev, iph->saddr,
- RT_SCOPE_LINK);
- else
- saddr = 0;
- rcu_read_unlock();
- }
- tos = icmp_pointers[type].error ? (RT_TOS(iph->tos) |
- IPTOS_PREC_INTERNETCONTROL) :
- iph->tos;
- mark = IP4_REPLY_MARK(net, skb_in->mark);
- if (__ip_options_echo(net, &icmp_param.replyopts.opt.opt, skb_in, opt))
- goto out_unlock;
- /*
- * Prepare data for ICMP header.
- */
- icmp_param.data.icmph.type = type;
- icmp_param.data.icmph.code = code;
- icmp_param.data.icmph.un.gateway = info;
- icmp_param.data.icmph.checksum = 0;
- icmp_param.skb = skb_in;
- icmp_param.offset = skb_network_offset(skb_in);
- inet_sk(sk)->tos = tos;
- ipcm_init(&ipc);
- ipc.addr = iph->saddr;
- ipc.opt = &icmp_param.replyopts.opt;
- ipc.sockc.mark = mark;
- rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
- type, code, &icmp_param);
- if (IS_ERR(rt))
- goto out_unlock;
- /* peer icmp_ratelimit */
- if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code))
- goto ende;
- /* RFC says return as much as we can without exceeding 576 bytes. */
- room = dst_mtu(&rt->dst);
- if (room > 576)
- room = 576;
- room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
- room -= sizeof(struct icmphdr);
- /* Guard against tiny mtu. We need to include at least one
- * IP network header for this message to make any sense.
- */
- if (room <= (int)sizeof(struct iphdr))
- goto ende;
- icmp_param.data_len = skb_in->len - icmp_param.offset;
- if (icmp_param.data_len > room)
- icmp_param.data_len = room;
- icmp_param.head_len = sizeof(struct icmphdr);
- /* if we don't have a source address at this point, fall back to the
- * dummy address instead of sending out a packet with a source address
- * of 0.0.0.0
- */
- if (!fl4.saddr)
- fl4.saddr = htonl(INADDR_DUMMY);
- icmp_push_reply(sk, &icmp_param, &fl4, &ipc, &rt);
- ende:
- ip_rt_put(rt);
- out_unlock:
- icmp_xmit_unlock(sk);
- out_bh_enable:
- local_bh_enable();
- out:;
- }
- EXPORT_SYMBOL(__icmp_send);
- #if IS_ENABLED(CONFIG_NF_NAT)
- #include <net/netfilter/nf_conntrack.h>
- void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info)
- {
- struct sk_buff *cloned_skb = NULL;
- struct ip_options opts = { 0 };
- enum ip_conntrack_info ctinfo;
- struct nf_conn *ct;
- __be32 orig_ip;
- ct = nf_ct_get(skb_in, &ctinfo);
- if (!ct || !(ct->status & IPS_SRC_NAT)) {
- __icmp_send(skb_in, type, code, info, &opts);
- return;
- }
- if (skb_shared(skb_in))
- skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC);
- if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head ||
- (skb_network_header(skb_in) + sizeof(struct iphdr)) >
- skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in,
- skb_network_offset(skb_in) + sizeof(struct iphdr))))
- goto out;
- orig_ip = ip_hdr(skb_in)->saddr;
- ip_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.ip;
- __icmp_send(skb_in, type, code, info, &opts);
- ip_hdr(skb_in)->saddr = orig_ip;
- out:
- consume_skb(cloned_skb);
- }
- EXPORT_SYMBOL(icmp_ndo_send);
- #endif
- static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
- {
- const struct iphdr *iph = (const struct iphdr *)skb->data;
- const struct net_protocol *ipprot;
- int protocol = iph->protocol;
- /* Checkin full IP header plus 8 bytes of protocol to
- * avoid additional coding at protocol handlers.
- */
- if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) {
- __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
- return;
- }
- raw_icmp_error(skb, protocol, info);
- ipprot = rcu_dereference(inet_protos[protocol]);
- if (ipprot && ipprot->err_handler)
- ipprot->err_handler(skb, info);
- }
- static bool icmp_tag_validation(int proto)
- {
- bool ok;
- rcu_read_lock();
- ok = rcu_dereference(inet_protos[proto])->icmp_strict_tag_validation;
- rcu_read_unlock();
- return ok;
- }
- /*
- * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEEDED, ICMP_QUENCH, and
- * ICMP_PARAMETERPROB.
- */
- static enum skb_drop_reason icmp_unreach(struct sk_buff *skb)
- {
- enum skb_drop_reason reason = SKB_NOT_DROPPED_YET;
- const struct iphdr *iph;
- struct icmphdr *icmph;
- struct net *net;
- u32 info = 0;
- net = dev_net(skb_dst(skb)->dev);
- /*
- * Incomplete header ?
- * Only checks for the IP header, there should be an
- * additional check for longer headers in upper levels.
- */
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
- goto out_err;
- icmph = icmp_hdr(skb);
- iph = (const struct iphdr *)skb->data;
- if (iph->ihl < 5) { /* Mangled header, drop. */
- reason = SKB_DROP_REASON_IP_INHDR;
- goto out_err;
- }
- switch (icmph->type) {
- case ICMP_DEST_UNREACH:
- switch (icmph->code & 15) {
- case ICMP_NET_UNREACH:
- case ICMP_HOST_UNREACH:
- case ICMP_PROT_UNREACH:
- case ICMP_PORT_UNREACH:
- break;
- case ICMP_FRAG_NEEDED:
- /* for documentation of the ip_no_pmtu_disc
- * values please see
- * Documentation/networking/ip-sysctl.rst
- */
- switch (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) {
- default:
- net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n",
- &iph->daddr);
- break;
- case 2:
- goto out;
- case 3:
- if (!icmp_tag_validation(iph->protocol))
- goto out;
- fallthrough;
- case 0:
- info = ntohs(icmph->un.frag.mtu);
- }
- break;
- case ICMP_SR_FAILED:
- net_dbg_ratelimited("%pI4: Source Route Failed\n",
- &iph->daddr);
- break;
- default:
- break;
- }
- if (icmph->code > NR_ICMP_UNREACH)
- goto out;
- break;
- case ICMP_PARAMETERPROB:
- info = ntohl(icmph->un.gateway) >> 24;
- break;
- case ICMP_TIME_EXCEEDED:
- __ICMP_INC_STATS(net, ICMP_MIB_INTIMEEXCDS);
- if (icmph->code == ICMP_EXC_FRAGTIME)
- goto out;
- break;
- }
- /*
- * Throw it at our lower layers
- *
- * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
- * header.
- * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
- * transport layer.
- * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
- * transport layer.
- */
- /*
- * Check the other end isn't violating RFC 1122. Some routers send
- * bogus responses to broadcast frames. If you see this message
- * first check your netmask matches at both ends, if it does then
- * get the other vendor to fix their kit.
- */
- if (!READ_ONCE(net->ipv4.sysctl_icmp_ignore_bogus_error_responses) &&
- inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
- net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
- &ip_hdr(skb)->saddr,
- icmph->type, icmph->code,
- &iph->daddr, skb->dev->name);
- goto out;
- }
- icmp_socket_deliver(skb, info);
- out:
- return reason;
- out_err:
- __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
- return reason ?: SKB_DROP_REASON_NOT_SPECIFIED;
- }
- /*
- * Handle ICMP_REDIRECT.
- */
- static enum skb_drop_reason icmp_redirect(struct sk_buff *skb)
- {
- if (skb->len < sizeof(struct iphdr)) {
- __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
- return SKB_DROP_REASON_PKT_TOO_SMALL;
- }
- if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
- /* there aught to be a stat */
- return SKB_DROP_REASON_NOMEM;
- }
- icmp_socket_deliver(skb, ntohl(icmp_hdr(skb)->un.gateway));
- return SKB_NOT_DROPPED_YET;
- }
- /*
- * Handle ICMP_ECHO ("ping") and ICMP_EXT_ECHO ("PROBE") requests.
- *
- * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
- * requests.
- * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
- * included in the reply.
- * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
- * echo requests, MUST have default=NOT.
- * RFC 8335: 8 MUST have a config option to enable/disable ICMP
- * Extended Echo Functionality, MUST be disabled by default
- * See also WRT handling of options once they are done and working.
- */
- static enum skb_drop_reason icmp_echo(struct sk_buff *skb)
- {
- struct icmp_bxm icmp_param;
- struct net *net;
- net = dev_net(skb_dst(skb)->dev);
- /* should there be an ICMP stat for ignored echos? */
- if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all))
- return SKB_NOT_DROPPED_YET;
- icmp_param.data.icmph = *icmp_hdr(skb);
- icmp_param.skb = skb;
- icmp_param.offset = 0;
- icmp_param.data_len = skb->len;
- icmp_param.head_len = sizeof(struct icmphdr);
- if (icmp_param.data.icmph.type == ICMP_ECHO)
- icmp_param.data.icmph.type = ICMP_ECHOREPLY;
- else if (!icmp_build_probe(skb, &icmp_param.data.icmph))
- return SKB_NOT_DROPPED_YET;
- icmp_reply(&icmp_param, skb);
- return SKB_NOT_DROPPED_YET;
- }
- /* Helper for icmp_echo and icmpv6_echo_reply.
- * Searches for net_device that matches PROBE interface identifier
- * and builds PROBE reply message in icmphdr.
- *
- * Returns false if PROBE responses are disabled via sysctl
- */
- bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
- {
- struct icmp_ext_hdr *ext_hdr, _ext_hdr;
- struct icmp_ext_echo_iio *iio, _iio;
- struct net *net = dev_net(skb->dev);
- struct net_device *dev;
- char buff[IFNAMSIZ];
- u16 ident_len;
- u8 status;
- if (!READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
- return false;
- /* We currently only support probing interfaces on the proxy node
- * Check to ensure L-bit is set
- */
- if (!(ntohs(icmphdr->un.echo.sequence) & 1))
- return false;
- /* Clear status bits in reply message */
- icmphdr->un.echo.sequence &= htons(0xFF00);
- if (icmphdr->type == ICMP_EXT_ECHO)
- icmphdr->type = ICMP_EXT_ECHOREPLY;
- else
- icmphdr->type = ICMPV6_EXT_ECHO_REPLY;
- ext_hdr = skb_header_pointer(skb, 0, sizeof(_ext_hdr), &_ext_hdr);
- /* Size of iio is class_type dependent.
- * Only check header here and assign length based on ctype in the switch statement
- */
- iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr), &_iio);
- if (!ext_hdr || !iio)
- goto send_mal_query;
- if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr) ||
- ntohs(iio->extobj_hdr.length) > sizeof(_iio))
- goto send_mal_query;
- ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr);
- iio = skb_header_pointer(skb, sizeof(_ext_hdr),
- sizeof(iio->extobj_hdr) + ident_len, &_iio);
- if (!iio)
- goto send_mal_query;
- status = 0;
- dev = NULL;
- switch (iio->extobj_hdr.class_type) {
- case ICMP_EXT_ECHO_CTYPE_NAME:
- if (ident_len >= IFNAMSIZ)
- goto send_mal_query;
- memset(buff, 0, sizeof(buff));
- memcpy(buff, &iio->ident.name, ident_len);
- dev = dev_get_by_name(net, buff);
- break;
- case ICMP_EXT_ECHO_CTYPE_INDEX:
- if (ident_len != sizeof(iio->ident.ifindex))
- goto send_mal_query;
- dev = dev_get_by_index(net, ntohl(iio->ident.ifindex));
- break;
- case ICMP_EXT_ECHO_CTYPE_ADDR:
- if (ident_len < sizeof(iio->ident.addr.ctype3_hdr) ||
- ident_len != sizeof(iio->ident.addr.ctype3_hdr) +
- iio->ident.addr.ctype3_hdr.addrlen)
- goto send_mal_query;
- switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) {
- case ICMP_AFI_IP:
- if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr))
- goto send_mal_query;
- dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr);
- break;
- #if IS_ENABLED(CONFIG_IPV6)
- case ICMP_AFI_IP6:
- if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr))
- goto send_mal_query;
- dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev);
- dev_hold(dev);
- break;
- #endif
- default:
- goto send_mal_query;
- }
- break;
- default:
- goto send_mal_query;
- }
- if (!dev) {
- icmphdr->code = ICMP_EXT_CODE_NO_IF;
- return true;
- }
- /* Fill bits in reply message */
- if (dev->flags & IFF_UP)
- status |= ICMP_EXT_ECHOREPLY_ACTIVE;
- if (__in_dev_get_rcu(dev) && __in_dev_get_rcu(dev)->ifa_list)
- status |= ICMP_EXT_ECHOREPLY_IPV4;
- if (!list_empty(&rcu_dereference(dev->ip6_ptr)->addr_list))
- status |= ICMP_EXT_ECHOREPLY_IPV6;
- dev_put(dev);
- icmphdr->un.echo.sequence |= htons(status);
- return true;
- send_mal_query:
- icmphdr->code = ICMP_EXT_CODE_MAL_QUERY;
- return true;
- }
- EXPORT_SYMBOL_GPL(icmp_build_probe);
- /*
- * Handle ICMP Timestamp requests.
- * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
- * SHOULD be in the kernel for minimum random latency.
- * MUST be accurate to a few minutes.
- * MUST be updated at least at 15Hz.
- */
- static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb)
- {
- struct icmp_bxm icmp_param;
- /*
- * Too short.
- */
- if (skb->len < 4)
- goto out_err;
- /*
- * Fill in the current time as ms since midnight UT:
- */
- icmp_param.data.times[1] = inet_current_timestamp();
- icmp_param.data.times[2] = icmp_param.data.times[1];
- BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));
- icmp_param.data.icmph = *icmp_hdr(skb);
- icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
- icmp_param.data.icmph.code = 0;
- icmp_param.skb = skb;
- icmp_param.offset = 0;
- icmp_param.data_len = 0;
- icmp_param.head_len = sizeof(struct icmphdr) + 12;
- icmp_reply(&icmp_param, skb);
- return SKB_NOT_DROPPED_YET;
- out_err:
- __ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
- return SKB_DROP_REASON_PKT_TOO_SMALL;
- }
- static enum skb_drop_reason icmp_discard(struct sk_buff *skb)
- {
- /* pretend it was a success */
- return SKB_NOT_DROPPED_YET;
- }
- /*
- * Deal with incoming ICMP packets.
- */
- int icmp_rcv(struct sk_buff *skb)
- {
- enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
- struct rtable *rt = skb_rtable(skb);
- struct net *net = dev_net(rt->dst.dev);
- struct icmphdr *icmph;
- if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
- struct sec_path *sp = skb_sec_path(skb);
- int nh;
- if (!(sp && sp->xvec[sp->len - 1]->props.flags &
- XFRM_STATE_ICMP)) {
- reason = SKB_DROP_REASON_XFRM_POLICY;
- goto drop;
- }
- if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
- goto drop;
- nh = skb_network_offset(skb);
- skb_set_network_header(skb, sizeof(*icmph));
- if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN,
- skb)) {
- reason = SKB_DROP_REASON_XFRM_POLICY;
- goto drop;
- }
- skb_set_network_header(skb, nh);
- }
- __ICMP_INC_STATS(net, ICMP_MIB_INMSGS);
- if (skb_checksum_simple_validate(skb))
- goto csum_error;
- if (!pskb_pull(skb, sizeof(*icmph)))
- goto error;
- icmph = icmp_hdr(skb);
- ICMPMSGIN_INC_STATS(net, icmph->type);
- /* Check for ICMP Extended Echo (PROBE) messages */
- if (icmph->type == ICMP_EXT_ECHO) {
- /* We can't use icmp_pointers[].handler() because it is an array of
- * size NR_ICMP_TYPES + 1 (19 elements) and PROBE has code 42.
- */
- reason = icmp_echo(skb);
- goto reason_check;
- }
- if (icmph->type == ICMP_EXT_ECHOREPLY) {
- reason = ping_rcv(skb);
- goto reason_check;
- }
- /*
- * 18 is the highest 'known' ICMP type. Anything else is a mystery
- *
- * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
- * discarded.
- */
- if (icmph->type > NR_ICMP_TYPES) {
- reason = SKB_DROP_REASON_UNHANDLED_PROTO;
- goto error;
- }
- /*
- * Parse the ICMP message
- */
- if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
- /*
- * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
- * silently ignored (we let user decide with a sysctl).
- * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
- * discarded if to broadcast/multicast.
- */
- if ((icmph->type == ICMP_ECHO ||
- icmph->type == ICMP_TIMESTAMP) &&
- READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_broadcasts)) {
- reason = SKB_DROP_REASON_INVALID_PROTO;
- goto error;
- }
- if (icmph->type != ICMP_ECHO &&
- icmph->type != ICMP_TIMESTAMP &&
- icmph->type != ICMP_ADDRESS &&
- icmph->type != ICMP_ADDRESSREPLY) {
- reason = SKB_DROP_REASON_INVALID_PROTO;
- goto error;
- }
- }
- reason = icmp_pointers[icmph->type].handler(skb);
- reason_check:
- if (!reason) {
- consume_skb(skb);
- return NET_RX_SUCCESS;
- }
- drop:
- kfree_skb_reason(skb, reason);
- return NET_RX_DROP;
- csum_error:
- reason = SKB_DROP_REASON_ICMP_CSUM;
- __ICMP_INC_STATS(net, ICMP_MIB_CSUMERRORS);
- error:
- __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
- goto drop;
- }
- static bool ip_icmp_error_rfc4884_validate(const struct sk_buff *skb, int off)
- {
- struct icmp_extobj_hdr *objh, _objh;
- struct icmp_ext_hdr *exth, _exth;
- u16 olen;
- exth = skb_header_pointer(skb, off, sizeof(_exth), &_exth);
- if (!exth)
- return false;
- if (exth->version != 2)
- return true;
- if (exth->checksum &&
- csum_fold(skb_checksum(skb, off, skb->len - off, 0)))
- return false;
- off += sizeof(_exth);
- while (off < skb->len) {
- objh = skb_header_pointer(skb, off, sizeof(_objh), &_objh);
- if (!objh)
- return false;
- olen = ntohs(objh->length);
- if (olen < sizeof(_objh))
- return false;
- off += olen;
- if (off > skb->len)
- return false;
- }
- return true;
- }
- void ip_icmp_error_rfc4884(const struct sk_buff *skb,
- struct sock_ee_data_rfc4884 *out,
- int thlen, int off)
- {
- int hlen;
- /* original datagram headers: end of icmph to payload (skb->data) */
- hlen = -skb_transport_offset(skb) - thlen;
- /* per rfc 4884: minimal datagram length of 128 bytes */
- if (off < 128 || off < hlen)
- return;
- /* kernel has stripped headers: return payload offset in bytes */
- off -= hlen;
- if (off + sizeof(struct icmp_ext_hdr) > skb->len)
- return;
- out->len = off;
- if (!ip_icmp_error_rfc4884_validate(skb, off))
- out->flags |= SO_EE_RFC4884_FLAG_INVALID;
- }
- EXPORT_SYMBOL_GPL(ip_icmp_error_rfc4884);
- int icmp_err(struct sk_buff *skb, u32 info)
- {
- struct iphdr *iph = (struct iphdr *)skb->data;
- int offset = iph->ihl<<2;
- struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset);
- int type = icmp_hdr(skb)->type;
- int code = icmp_hdr(skb)->code;
- struct net *net = dev_net(skb->dev);
- /*
- * Use ping_err to handle all icmp errors except those
- * triggered by ICMP_ECHOREPLY which sent from kernel.
- */
- if (icmph->type != ICMP_ECHOREPLY) {
- ping_err(skb, offset, info);
- return 0;
- }
- if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
- ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ICMP);
- else if (type == ICMP_REDIRECT)
- ipv4_redirect(skb, net, 0, IPPROTO_ICMP);
- return 0;
- }
- /*
- * This table is the definition of how we handle ICMP.
- */
- static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
- [ICMP_ECHOREPLY] = {
- .handler = ping_rcv,
- },
- [1] = {
- .handler = icmp_discard,
- .error = 1,
- },
- [2] = {
- .handler = icmp_discard,
- .error = 1,
- },
- [ICMP_DEST_UNREACH] = {
- .handler = icmp_unreach,
- .error = 1,
- },
- [ICMP_SOURCE_QUENCH] = {
- .handler = icmp_unreach,
- .error = 1,
- },
- [ICMP_REDIRECT] = {
- .handler = icmp_redirect,
- .error = 1,
- },
- [6] = {
- .handler = icmp_discard,
- .error = 1,
- },
- [7] = {
- .handler = icmp_discard,
- .error = 1,
- },
- [ICMP_ECHO] = {
- .handler = icmp_echo,
- },
- [9] = {
- .handler = icmp_discard,
- .error = 1,
- },
- [10] = {
- .handler = icmp_discard,
- .error = 1,
- },
- [ICMP_TIME_EXCEEDED] = {
- .handler = icmp_unreach,
- .error = 1,
- },
- [ICMP_PARAMETERPROB] = {
- .handler = icmp_unreach,
- .error = 1,
- },
- [ICMP_TIMESTAMP] = {
- .handler = icmp_timestamp,
- },
- [ICMP_TIMESTAMPREPLY] = {
- .handler = icmp_discard,
- },
- [ICMP_INFO_REQUEST] = {
- .handler = icmp_discard,
- },
- [ICMP_INFO_REPLY] = {
- .handler = icmp_discard,
- },
- [ICMP_ADDRESS] = {
- .handler = icmp_discard,
- },
- [ICMP_ADDRESSREPLY] = {
- .handler = icmp_discard,
- },
- };
- static int __net_init icmp_sk_init(struct net *net)
- {
- /* Control parameters for ECHO replies. */
- net->ipv4.sysctl_icmp_echo_ignore_all = 0;
- net->ipv4.sysctl_icmp_echo_enable_probe = 0;
- net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
- /* Control parameter - ignore bogus broadcast responses? */
- net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
- /*
- * Configurable global rate limit.
- *
- * ratelimit defines tokens/packet consumed for dst->rate_token
- * bucket ratemask defines which icmp types are ratelimited by
- * setting it's bit position.
- *
- * default:
- * dest unreachable (3), source quench (4),
- * time exceeded (11), parameter problem (12)
- */
- net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
- net->ipv4.sysctl_icmp_ratemask = 0x1818;
- net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
- return 0;
- }
- static struct pernet_operations __net_initdata icmp_sk_ops = {
- .init = icmp_sk_init,
- };
- int __init icmp_init(void)
- {
- int err, i;
- for_each_possible_cpu(i) {
- struct sock *sk;
- err = inet_ctl_sock_create(&sk, PF_INET,
- SOCK_RAW, IPPROTO_ICMP, &init_net);
- if (err < 0)
- return err;
- per_cpu(ipv4_icmp_sk, i) = sk;
- /* Enough space for 2 64K ICMP packets, including
- * sk_buff/skb_shared_info struct overhead.
- */
- sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
- /*
- * Speedup sock_wfree()
- */
- sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
- inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
- }
- return register_pernet_subsys(&icmp_sk_ops);
- }
|