| /* |
| * NET3: Implementation of the ICMP protocol layer. |
| * |
| * Alan Cox, <alan@lxorguk.ukuu.org.uk> |
| * |
| * 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. |
| * |
| * 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 <asm/uaccess.h> |
| #include <net/checksum.h> |
| #include <net/xfrm.h> |
| #include <net/inet_common.h> |
| #include <net/ip_fib.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 { |
| void (*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]; |
| |
| /* |
| * The ICMP socket(s). This is the most convenient way to flow control |
| * our ICMP output as well as maintain a clean interface throughout |
| * all layers. All Socketless IP sends will soon be gone. |
| * |
| * On SMP we have one ICMP socket per-cpu. |
| */ |
| static struct sock *icmp_sk(struct net *net) |
| { |
| return net->ipv4.icmp_sk[smp_processor_id()]; |
| } |
| |
| static inline struct sock *icmp_xmit_lock(struct net *net) |
| { |
| struct sock *sk; |
| |
| local_bh_disable(); |
| |
| sk = icmp_sk(net); |
| |
| 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. |
| */ |
| local_bh_enable(); |
| return NULL; |
| } |
| return sk; |
| } |
| |
| static inline void icmp_xmit_unlock(struct sock *sk) |
| { |
| spin_unlock_bh(&sk->sk_lock.slock); |
| } |
| |
| /* |
| * Send an ICMP frame. |
| */ |
| |
| static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, |
| struct flowi4 *fl4, int type, int code) |
| { |
| struct dst_entry *dst = &rt->dst; |
| bool rc = true; |
| |
| if (type > NR_ICMP_TYPES) |
| goto out; |
| |
| /* Don't limit PMTU discovery. */ |
| if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) |
| goto out; |
| |
| /* No rate limit on loopback */ |
| if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) |
| goto out; |
| |
| /* Limit if icmp type is enabled in ratemask. */ |
| if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) { |
| struct inet_peer *peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, 1); |
| rc = inet_peer_xrlim_allow(peer, |
| net->ipv4.sysctl_icmp_ratelimit); |
| 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 = (struct icmp_bxm *)from; |
| __wsum csum; |
| |
| csum = skb_copy_and_csum_bits(icmp_param->skb, |
| icmp_param->offset + offset, |
| to, len, 0); |
| |
| 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 icmp_bxm *icmp_param, |
| struct flowi4 *fl4, |
| struct ipcm_cookie *ipc, struct rtable **rt) |
| { |
| struct sock *sk; |
| struct sk_buff *skb; |
| |
| sk = icmp_sk(dev_net((*rt)->dst.dev)); |
| 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_BH(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 = 0; |
| struct sk_buff *skb1; |
| |
| skb_queue_walk(&sk->sk_write_queue, skb1) { |
| csum = csum_add(csum, skb1->csum); |
| } |
| csum = csum_partial_copy_nocheck((void *)&icmp_param->data, |
| (char *)icmph, |
| icmp_param->head_len, 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; |
| |
| if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb)) |
| return; |
| |
| sk = icmp_xmit_lock(net); |
| if (sk == NULL) |
| return; |
| inet = inet_sk(sk); |
| |
| icmp_param->data.icmph.checksum = 0; |
| |
| inet->tos = ip_hdr(skb)->tos; |
| daddr = ipc.addr = ip_hdr(skb)->saddr; |
| saddr = fib_compute_spec_dst(skb); |
| ipc.opt = NULL; |
| ipc.tx_flags = 0; |
| 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_tos = RT_TOS(ip_hdr(skb)->tos); |
| fl4.flowi4_proto = IPPROTO_ICMP; |
| security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); |
| rt = ip_route_output_key(net, &fl4); |
| if (IS_ERR(rt)) |
| goto out_unlock; |
| if (icmpv4_xrlim_allow(net, rt, &fl4, icmp_param->data.icmph.type, |
| icmp_param->data.icmph.code)) |
| icmp_push_reply(icmp_param, &fl4, &ipc, &rt); |
| ip_rt_put(rt); |
| out_unlock: |
| icmp_xmit_unlock(sk); |
| } |
| |
| 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, |
| int type, int code, |
| struct icmp_bxm *param) |
| { |
| 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_tos = RT_TOS(tos); |
| fl4->flowi4_proto = IPPROTO_ICMP; |
| fl4->fl4_icmp_type = type; |
| fl4->fl4_icmp_code = code; |
| security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4)); |
| rt = __ip_route_output_key(net, fl4); |
| 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(net, 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 */ |
| 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) |
| { |
| 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; |
| struct net *net; |
| struct sock *sk; |
| |
| if (!rt) |
| goto out; |
| net = dev_net(rt->dst.dev); |
| |
| /* |
| * 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_in->network_header + sizeof(*iph)) > skb_in->tail) |
| 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 == NULL) |
| 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; |
| } |
| } |
| |
| sk = icmp_xmit_lock(net); |
| if (sk == NULL) |
| return; |
| |
| /* |
| * 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) && |
| net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr) |
| dev = dev_get_by_index_rcu(net, rt->rt_iif); |
| |
| if (dev) |
| saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK); |
| else |
| saddr = 0; |
| rcu_read_unlock(); |
| } |
| |
| tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) | |
| IPTOS_PREC_INTERNETCONTROL) : |
| iph->tos; |
| |
| if (ip_options_echo(&icmp_param.replyopts.opt.opt, skb_in)) |
| 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; |
| ipc.addr = iph->saddr; |
| ipc.opt = &icmp_param.replyopts.opt; |
| ipc.tx_flags = 0; |
| |
| rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, |
| type, code, &icmp_param); |
| if (IS_ERR(rt)) |
| goto out_unlock; |
| |
| 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); |
| |
| 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); |
| |
| icmp_push_reply(&icmp_param, &fl4, &ipc, &rt); |
| ende: |
| ip_rt_put(rt); |
| out_unlock: |
| icmp_xmit_unlock(sk); |
| out:; |
| } |
| EXPORT_SYMBOL(icmp_send); |
| |
| |
| 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)) |
| return; |
| |
| raw_icmp_error(skb, protocol, info); |
| |
| rcu_read_lock(); |
| ipprot = rcu_dereference(inet_protos[protocol]); |
| if (ipprot && ipprot->err_handler) |
| ipprot->err_handler(skb, info); |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH. |
| */ |
| |
| static void icmp_unreach(struct sk_buff *skb) |
| { |
| 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. */ |
| goto out_err; |
| |
| if (icmph->type == 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: |
| if (ipv4_config.no_pmtu_disc) { |
| LIMIT_NETDEBUG(KERN_INFO pr_fmt("%pI4: fragmentation needed and DF set\n"), |
| &iph->daddr); |
| } else { |
| info = ntohs(icmph->un.frag.mtu); |
| if (!info) |
| goto out; |
| } |
| break; |
| case ICMP_SR_FAILED: |
| LIMIT_NETDEBUG(KERN_INFO pr_fmt("%pI4: Source Route Failed\n"), |
| &iph->daddr); |
| break; |
| default: |
| break; |
| } |
| if (icmph->code > NR_ICMP_UNREACH) |
| goto out; |
| } else if (icmph->type == ICMP_PARAMETERPROB) |
| info = ntohl(icmph->un.gateway) >> 24; |
| |
| /* |
| * 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 (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses && |
| inet_addr_type(net, 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; |
| out_err: |
| ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
| goto out; |
| } |
| |
| |
| /* |
| * Handle ICMP_REDIRECT. |
| */ |
| |
| static void icmp_redirect(struct sk_buff *skb) |
| { |
| if (skb->len < sizeof(struct iphdr)) { |
| ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS); |
| return; |
| } |
| |
| if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
| return; |
| |
| icmp_socket_deliver(skb, icmp_hdr(skb)->un.gateway); |
| } |
| |
| /* |
| * Handle ICMP_ECHO ("ping") 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. |
| * See also WRT handling of options once they are done and working. |
| */ |
| |
| static void icmp_echo(struct sk_buff *skb) |
| { |
| struct net *net; |
| |
| net = dev_net(skb_dst(skb)->dev); |
| if (!net->ipv4.sysctl_icmp_echo_ignore_all) { |
| struct icmp_bxm icmp_param; |
| |
| icmp_param.data.icmph = *icmp_hdr(skb); |
| icmp_param.data.icmph.type = ICMP_ECHOREPLY; |
| icmp_param.skb = skb; |
| icmp_param.offset = 0; |
| icmp_param.data_len = skb->len; |
| icmp_param.head_len = sizeof(struct icmphdr); |
| icmp_reply(&icmp_param, skb); |
| } |
| } |
| |
| /* |
| * 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 void icmp_timestamp(struct sk_buff *skb) |
| { |
| struct timespec tv; |
| struct icmp_bxm icmp_param; |
| /* |
| * Too short. |
| */ |
| if (skb->len < 4) |
| goto out_err; |
| |
| /* |
| * Fill in the current time as ms since midnight UT: |
| */ |
| getnstimeofday(&tv); |
| icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + |
| tv.tv_nsec / NSEC_PER_MSEC); |
| icmp_param.data.times[2] = icmp_param.data.times[1]; |
| if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4)) |
| BUG(); |
| 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); |
| out: |
| return; |
| out_err: |
| ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS); |
| goto out; |
| } |
| |
| |
| /* |
| * Handle ICMP_ADDRESS_MASK requests. (RFC950) |
| * |
| * RFC1122 (3.2.2.9). A host MUST only send replies to |
| * ADDRESS_MASK requests if it's been configured as an address mask |
| * agent. Receiving a request doesn't constitute implicit permission to |
| * act as one. Of course, implementing this correctly requires (SHOULD) |
| * a way to turn the functionality on and off. Another one for sysctl(), |
| * I guess. -- MS |
| * |
| * RFC1812 (4.3.3.9). A router MUST implement it. |
| * A router SHOULD have switch turning it on/off. |
| * This switch MUST be ON by default. |
| * |
| * Gratuitous replies, zero-source replies are not implemented, |
| * that complies with RFC. DO NOT implement them!!! All the idea |
| * of broadcast addrmask replies as specified in RFC950 is broken. |
| * The problem is that it is not uncommon to have several prefixes |
| * on one physical interface. Moreover, addrmask agent can even be |
| * not aware of existing another prefixes. |
| * If source is zero, addrmask agent cannot choose correct prefix. |
| * Gratuitous mask announcements suffer from the same problem. |
| * RFC1812 explains it, but still allows to use ADDRMASK, |
| * that is pretty silly. --ANK |
| * |
| * All these rules are so bizarre, that I removed kernel addrmask |
| * support at all. It is wrong, it is obsolete, nobody uses it in |
| * any case. --ANK |
| * |
| * Furthermore you can do it with a usermode address agent program |
| * anyway... |
| */ |
| |
| static void icmp_address(struct sk_buff *skb) |
| { |
| #if 0 |
| net_dbg_ratelimited("a guy asks for address mask. Who is it?\n"); |
| #endif |
| } |
| |
| /* |
| * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain |
| * loudly if an inconsistency is found. |
| * called with rcu_read_lock() |
| */ |
| |
| static void icmp_address_reply(struct sk_buff *skb) |
| { |
| struct rtable *rt = skb_rtable(skb); |
| struct net_device *dev = skb->dev; |
| struct in_device *in_dev; |
| struct in_ifaddr *ifa; |
| |
| if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC)) |
| return; |
| |
| in_dev = __in_dev_get_rcu(dev); |
| if (!in_dev) |
| return; |
| |
| if (in_dev->ifa_list && |
| IN_DEV_LOG_MARTIANS(in_dev) && |
| IN_DEV_FORWARD(in_dev)) { |
| __be32 _mask, *mp; |
| |
| mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask); |
| BUG_ON(mp == NULL); |
| for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) { |
| if (*mp == ifa->ifa_mask && |
| inet_ifa_match(ip_hdr(skb)->saddr, ifa)) |
| break; |
| } |
| if (!ifa) |
| net_info_ratelimited("Wrong address mask %pI4 from %s/%pI4\n", |
| mp, |
| dev->name, &ip_hdr(skb)->saddr); |
| } |
| } |
| |
| static void icmp_discard(struct sk_buff *skb) |
| { |
| } |
| |
| /* |
| * Deal with incoming ICMP packets. |
| */ |
| int icmp_rcv(struct sk_buff *skb) |
| { |
| struct icmphdr *icmph; |
| struct rtable *rt = skb_rtable(skb); |
| struct net *net = dev_net(rt->dst.dev); |
| |
| 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)) |
| 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)) |
| goto drop; |
| |
| skb_set_network_header(skb, nh); |
| } |
| |
| ICMP_INC_STATS_BH(net, ICMP_MIB_INMSGS); |
| |
| switch (skb->ip_summed) { |
| case CHECKSUM_COMPLETE: |
| if (!csum_fold(skb->csum)) |
| break; |
| /* fall through */ |
| case CHECKSUM_NONE: |
| skb->csum = 0; |
| if (__skb_checksum_complete(skb)) |
| goto error; |
| } |
| |
| if (!pskb_pull(skb, sizeof(*icmph))) |
| goto error; |
| |
| icmph = icmp_hdr(skb); |
| |
| ICMPMSGIN_INC_STATS_BH(net, icmph->type); |
| /* |
| * 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) |
| 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) && |
| net->ipv4.sysctl_icmp_echo_ignore_broadcasts) { |
| goto error; |
| } |
| if (icmph->type != ICMP_ECHO && |
| icmph->type != ICMP_TIMESTAMP && |
| icmph->type != ICMP_ADDRESS && |
| icmph->type != ICMP_ADDRESSREPLY) { |
| goto error; |
| } |
| } |
| |
| icmp_pointers[icmph->type].handler(skb); |
| |
| drop: |
| kfree_skb(skb); |
| return 0; |
| error: |
| ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
| goto drop; |
| } |
| |
| /* |
| * 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_address, |
| }, |
| [ICMP_ADDRESSREPLY] = { |
| .handler = icmp_address_reply, |
| }, |
| }; |
| |
| static void __net_exit icmp_sk_exit(struct net *net) |
| { |
| int i; |
| |
| for_each_possible_cpu(i) |
| inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]); |
| kfree(net->ipv4.icmp_sk); |
| net->ipv4.icmp_sk = NULL; |
| } |
| |
| static int __net_init icmp_sk_init(struct net *net) |
| { |
| int i, err; |
| |
| net->ipv4.icmp_sk = |
| kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); |
| if (net->ipv4.icmp_sk == NULL) |
| return -ENOMEM; |
| |
| for_each_possible_cpu(i) { |
| struct sock *sk; |
| |
| err = inet_ctl_sock_create(&sk, PF_INET, |
| SOCK_RAW, IPPROTO_ICMP, net); |
| if (err < 0) |
| goto fail; |
| |
| net->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; |
| } |
| |
| /* Control parameters for ECHO replies. */ |
| net->ipv4.sysctl_icmp_echo_ignore_all = 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; |
| |
| fail: |
| for_each_possible_cpu(i) |
| inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]); |
| kfree(net->ipv4.icmp_sk); |
| return err; |
| } |
| |
| static struct pernet_operations __net_initdata icmp_sk_ops = { |
| .init = icmp_sk_init, |
| .exit = icmp_sk_exit, |
| }; |
| |
| int __init icmp_init(void) |
| { |
| return register_pernet_subsys(&icmp_sk_ops); |
| } |