![David Ahern](/assets/img/avatar_default.png)
Currently inet_addr_type and inet_dev_addr_type expect local addresses to be in the local table. With the VRF device local routes for devices associated with a VRF will be in the table associated with the VRF. Provide an alternate inet_addr lookup to use a specific table rather than defaulting to the local table. inet_addr_type_dev_table keeps the same semantics as inet_addr_type but if the passed in device is enslaved to a VRF then the table for that VRF is used for the lookup. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1225 lines
29 KiB
C
1225 lines
29 KiB
C
/*
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* NET3: Implementation of the ICMP protocol layer.
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*
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* Alan Cox, <alan@lxorguk.ukuu.org.uk>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Some of the function names and the icmp unreach table for this
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* module were derived from [icmp.c 1.0.11 06/02/93] by
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* Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
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* Other than that this module is a complete rewrite.
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*
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* Fixes:
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* Clemens Fruhwirth : introduce global icmp rate limiting
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* with icmp type masking ability instead
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* of broken per type icmp timeouts.
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* Mike Shaver : RFC1122 checks.
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* Alan Cox : Multicast ping reply as self.
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* Alan Cox : Fix atomicity lockup in ip_build_xmit
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* call.
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* Alan Cox : Added 216,128 byte paths to the MTU
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* code.
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* Martin Mares : RFC1812 checks.
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* Martin Mares : Can be configured to follow redirects
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* if acting as a router _without_ a
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* routing protocol (RFC 1812).
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* Martin Mares : Echo requests may be configured to
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* be ignored (RFC 1812).
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* Martin Mares : Limitation of ICMP error message
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* transmit rate (RFC 1812).
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* Martin Mares : TOS and Precedence set correctly
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* (RFC 1812).
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* Martin Mares : Now copying as much data from the
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* original packet as we can without
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* exceeding 576 bytes (RFC 1812).
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* Willy Konynenberg : Transparent proxying support.
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* Keith Owens : RFC1191 correction for 4.2BSD based
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* path MTU bug.
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* Thomas Quinot : ICMP Dest Unreach codes up to 15 are
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* valid (RFC 1812).
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* Andi Kleen : Check all packet lengths properly
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* and moved all kfree_skb() up to
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* icmp_rcv.
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* Andi Kleen : Move the rate limit bookkeeping
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* into the dest entry and use a token
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* bucket filter (thanks to ANK). Make
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* the rates sysctl configurable.
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* Yu Tianli : Fixed two ugly bugs in icmp_send
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* - IP option length was accounted wrongly
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* - ICMP header length was not accounted
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* at all.
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* Tristan Greaves : Added sysctl option to ignore bogus
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* broadcast responses from broken routers.
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*
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* To Fix:
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*
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* - Should use skb_pull() instead of all the manual checking.
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* This would also greatly simply some upper layer error handlers. --AK
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/fcntl.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <linux/inetdevice.h>
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#include <linux/netdevice.h>
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#include <linux/string.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/slab.h>
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#include <net/snmp.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <net/protocol.h>
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#include <net/icmp.h>
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#include <net/tcp.h>
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#include <net/udp.h>
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#include <net/raw.h>
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#include <net/ping.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <linux/errno.h>
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#include <linux/timer.h>
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#include <linux/init.h>
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#include <asm/uaccess.h>
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#include <net/checksum.h>
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#include <net/xfrm.h>
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#include <net/inet_common.h>
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#include <net/ip_fib.h>
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#include <net/vrf.h>
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/*
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* Build xmit assembly blocks
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*/
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struct icmp_bxm {
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struct sk_buff *skb;
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int offset;
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int data_len;
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struct {
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struct icmphdr icmph;
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__be32 times[3];
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} data;
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int head_len;
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struct ip_options_data replyopts;
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};
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/* An array of errno for error messages from dest unreach. */
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/* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
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const struct icmp_err icmp_err_convert[] = {
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{
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.errno = ENETUNREACH, /* ICMP_NET_UNREACH */
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.fatal = 0,
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},
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{
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.errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
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.fatal = 0,
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},
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{
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.errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
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.fatal = 1,
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},
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{
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.errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
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.fatal = 1,
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},
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{
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.errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
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.fatal = 0,
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},
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{
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.errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
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.fatal = 0,
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},
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{
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.errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
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.fatal = 1,
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},
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{
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.errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
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.fatal = 1,
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},
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{
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.errno = ENONET, /* ICMP_HOST_ISOLATED */
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.fatal = 1,
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},
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{
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.errno = ENETUNREACH, /* ICMP_NET_ANO */
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.fatal = 1,
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},
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{
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.errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
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.fatal = 1,
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},
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{
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.errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
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.fatal = 0,
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},
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{
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.errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
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.fatal = 0,
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},
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{
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.errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
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.fatal = 1,
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},
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{
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.errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
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.fatal = 1,
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},
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{
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.errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
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.fatal = 1,
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},
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};
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EXPORT_SYMBOL(icmp_err_convert);
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/*
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* ICMP control array. This specifies what to do with each ICMP.
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*/
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struct icmp_control {
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bool (*handler)(struct sk_buff *skb);
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short error; /* This ICMP is classed as an error message */
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};
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static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
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/*
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* The ICMP socket(s). This is the most convenient way to flow control
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* our ICMP output as well as maintain a clean interface throughout
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* all layers. All Socketless IP sends will soon be gone.
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*
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* On SMP we have one ICMP socket per-cpu.
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*/
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static struct sock *icmp_sk(struct net *net)
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{
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return *this_cpu_ptr(net->ipv4.icmp_sk);
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}
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static inline struct sock *icmp_xmit_lock(struct net *net)
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{
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struct sock *sk;
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local_bh_disable();
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sk = icmp_sk(net);
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if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
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/* This can happen if the output path signals a
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* dst_link_failure() for an outgoing ICMP packet.
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*/
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local_bh_enable();
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return NULL;
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}
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return sk;
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}
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static inline void icmp_xmit_unlock(struct sock *sk)
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{
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spin_unlock_bh(&sk->sk_lock.slock);
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}
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int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
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int sysctl_icmp_msgs_burst __read_mostly = 50;
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static struct {
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spinlock_t lock;
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u32 credit;
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u32 stamp;
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} icmp_global = {
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.lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock),
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};
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/**
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* icmp_global_allow - Are we allowed to send one more ICMP message ?
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*
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* Uses a token bucket to limit our ICMP messages to sysctl_icmp_msgs_per_sec.
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* Returns false if we reached the limit and can not send another packet.
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* Note: called with BH disabled
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*/
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bool icmp_global_allow(void)
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{
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u32 credit, delta, incr = 0, now = (u32)jiffies;
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bool rc = false;
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/* Check if token bucket is empty and cannot be refilled
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* without taking the spinlock.
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*/
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if (!icmp_global.credit) {
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delta = min_t(u32, now - icmp_global.stamp, HZ);
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if (delta < HZ / 50)
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return false;
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}
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spin_lock(&icmp_global.lock);
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delta = min_t(u32, now - icmp_global.stamp, HZ);
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if (delta >= HZ / 50) {
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incr = sysctl_icmp_msgs_per_sec * delta / HZ ;
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if (incr)
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icmp_global.stamp = now;
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}
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credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst);
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if (credit) {
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credit--;
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rc = true;
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}
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icmp_global.credit = credit;
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spin_unlock(&icmp_global.lock);
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return rc;
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}
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EXPORT_SYMBOL(icmp_global_allow);
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/*
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* Send an ICMP frame.
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*/
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static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
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struct flowi4 *fl4, int type, int code)
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{
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struct dst_entry *dst = &rt->dst;
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bool rc = true;
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if (type > NR_ICMP_TYPES)
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goto out;
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/* Don't limit PMTU discovery. */
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if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
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goto out;
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/* No rate limit on loopback */
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if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
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goto out;
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/* Limit if icmp type is enabled in ratemask. */
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if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask))
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goto out;
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rc = false;
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if (icmp_global_allow()) {
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struct inet_peer *peer;
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peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, 1);
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rc = inet_peer_xrlim_allow(peer,
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net->ipv4.sysctl_icmp_ratelimit);
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if (peer)
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inet_putpeer(peer);
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}
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out:
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return rc;
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}
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/*
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* Maintain the counters used in the SNMP statistics for outgoing ICMP
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*/
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void icmp_out_count(struct net *net, unsigned char type)
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{
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ICMPMSGOUT_INC_STATS(net, type);
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ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
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}
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/*
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* Checksum each fragment, and on the first include the headers and final
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* checksum.
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*/
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static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
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struct sk_buff *skb)
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{
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struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
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__wsum csum;
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csum = skb_copy_and_csum_bits(icmp_param->skb,
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icmp_param->offset + offset,
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to, len, 0);
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skb->csum = csum_block_add(skb->csum, csum, odd);
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if (icmp_pointers[icmp_param->data.icmph.type].error)
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nf_ct_attach(skb, icmp_param->skb);
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return 0;
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}
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static void icmp_push_reply(struct icmp_bxm *icmp_param,
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struct flowi4 *fl4,
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struct ipcm_cookie *ipc, struct rtable **rt)
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{
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struct sock *sk;
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struct sk_buff *skb;
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sk = icmp_sk(dev_net((*rt)->dst.dev));
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if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
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icmp_param->data_len+icmp_param->head_len,
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icmp_param->head_len,
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ipc, rt, MSG_DONTWAIT) < 0) {
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ICMP_INC_STATS_BH(sock_net(sk), ICMP_MIB_OUTERRORS);
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ip_flush_pending_frames(sk);
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} else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
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struct icmphdr *icmph = icmp_hdr(skb);
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__wsum csum = 0;
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struct sk_buff *skb1;
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skb_queue_walk(&sk->sk_write_queue, skb1) {
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csum = csum_add(csum, skb1->csum);
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}
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csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
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(char *)icmph,
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icmp_param->head_len, csum);
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icmph->checksum = csum_fold(csum);
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skb->ip_summed = CHECKSUM_NONE;
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ip_push_pending_frames(sk, fl4);
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}
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}
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/*
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* Driving logic for building and sending ICMP messages.
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*/
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static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
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{
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struct ipcm_cookie ipc;
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struct rtable *rt = skb_rtable(skb);
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struct net *net = dev_net(rt->dst.dev);
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struct flowi4 fl4;
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struct sock *sk;
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struct inet_sock *inet;
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__be32 daddr, saddr;
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u32 mark = IP4_REPLY_MARK(net, skb->mark);
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if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb))
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return;
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sk = icmp_xmit_lock(net);
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if (!sk)
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return;
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inet = inet_sk(sk);
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icmp_param->data.icmph.checksum = 0;
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inet->tos = ip_hdr(skb)->tos;
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sk->sk_mark = mark;
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daddr = ipc.addr = ip_hdr(skb)->saddr;
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saddr = fib_compute_spec_dst(skb);
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ipc.opt = NULL;
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ipc.tx_flags = 0;
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ipc.ttl = 0;
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ipc.tos = -1;
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if (icmp_param->replyopts.opt.opt.optlen) {
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ipc.opt = &icmp_param->replyopts.opt;
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if (ipc.opt->opt.srr)
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daddr = icmp_param->replyopts.opt.opt.faddr;
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}
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memset(&fl4, 0, sizeof(fl4));
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fl4.daddr = daddr;
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fl4.saddr = saddr;
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fl4.flowi4_mark = mark;
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fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
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fl4.flowi4_proto = IPPROTO_ICMP;
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fl4.flowi4_oif = vrf_master_ifindex_rcu(skb->dev) ? : skb->dev->ifindex;
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security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
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rt = ip_route_output_key(net, &fl4);
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if (IS_ERR(rt))
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goto out_unlock;
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if (icmpv4_xrlim_allow(net, rt, &fl4, icmp_param->data.icmph.type,
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icmp_param->data.icmph.code))
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icmp_push_reply(icmp_param, &fl4, &ipc, &rt);
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ip_rt_put(rt);
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out_unlock:
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icmp_xmit_unlock(sk);
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}
|
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|
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static struct rtable *icmp_route_lookup(struct net *net,
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struct flowi4 *fl4,
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struct sk_buff *skb_in,
|
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const struct iphdr *iph,
|
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__be32 saddr, u8 tos, u32 mark,
|
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int type, int code,
|
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struct icmp_bxm *param)
|
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{
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struct rtable *rt, *rt2;
|
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struct flowi4 fl4_dec;
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int err;
|
|
|
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memset(fl4, 0, sizeof(*fl4));
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fl4->daddr = (param->replyopts.opt.opt.srr ?
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param->replyopts.opt.opt.faddr : iph->saddr);
|
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fl4->saddr = saddr;
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fl4->flowi4_mark = mark;
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fl4->flowi4_tos = RT_TOS(tos);
|
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fl4->flowi4_proto = IPPROTO_ICMP;
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fl4->fl4_icmp_type = type;
|
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fl4->fl4_icmp_code = code;
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fl4->flowi4_oif = vrf_master_ifindex_rcu(skb_in->dev) ? : skb_in->dev->ifindex;
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|
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security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4));
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rt = __ip_route_output_key(net, fl4);
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if (IS_ERR(rt))
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return rt;
|
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|
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/* No need to clone since we're just using its address. */
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rt2 = rt;
|
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|
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rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
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flowi4_to_flowi(fl4), NULL, 0);
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if (!IS_ERR(rt)) {
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if (rt != rt2)
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return rt;
|
|
} else if (PTR_ERR(rt) == -EPERM) {
|
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rt = NULL;
|
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} else
|
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return rt;
|
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|
|
err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
|
|
if (err)
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goto relookup_failed;
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|
|
if (inet_addr_type_dev_table(net, skb_in->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)
|
|
{
|
|
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;
|
|
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_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;
|
|
}
|
|
}
|
|
|
|
icmp_param = kmalloc(sizeof(*icmp_param), GFP_ATOMIC);
|
|
if (!icmp_param)
|
|
return;
|
|
|
|
sk = icmp_xmit_lock(net);
|
|
if (!sk)
|
|
goto out_free;
|
|
|
|
/*
|
|
* 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, inet_iif(skb_in));
|
|
|
|
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;
|
|
mark = IP4_REPLY_MARK(net, skb_in->mark);
|
|
|
|
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;
|
|
sk->sk_mark = mark;
|
|
ipc.addr = iph->saddr;
|
|
ipc.opt = &icmp_param->replyopts.opt;
|
|
ipc.tx_flags = 0;
|
|
ipc.ttl = 0;
|
|
ipc.tos = -1;
|
|
|
|
rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
|
|
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_free:
|
|
kfree(icmp_param);
|
|
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)) {
|
|
ICMP_INC_STATS_BH(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_EXCEED, ICMP_QUENCH, and
|
|
* ICMP_PARAMETERPROB.
|
|
*/
|
|
|
|
static bool 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:
|
|
/* for documentation of the ip_no_pmtu_disc
|
|
* values please see
|
|
* Documentation/networking/ip-sysctl.txt
|
|
*/
|
|
switch (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;
|
|
/* fall through */
|
|
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;
|
|
} 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_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 true;
|
|
out_err:
|
|
ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
|
|
return false;
|
|
}
|
|
|
|
|
|
/*
|
|
* Handle ICMP_REDIRECT.
|
|
*/
|
|
|
|
static bool icmp_redirect(struct sk_buff *skb)
|
|
{
|
|
if (skb->len < sizeof(struct iphdr)) {
|
|
ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
|
|
return false;
|
|
}
|
|
|
|
if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
|
|
/* there aught to be a stat */
|
|
return false;
|
|
}
|
|
|
|
icmp_socket_deliver(skb, icmp_hdr(skb)->un.gateway);
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* 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 bool 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);
|
|
}
|
|
/* should there be an ICMP stat for ignored echos? */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* 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 bool 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);
|
|
return true;
|
|
|
|
out_err:
|
|
ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
|
|
return false;
|
|
}
|
|
|
|
static bool icmp_discard(struct sk_buff *skb)
|
|
{
|
|
/* pretend it was a success */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
bool success;
|
|
|
|
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);
|
|
|
|
if (skb_checksum_simple_validate(skb))
|
|
goto csum_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;
|
|
}
|
|
}
|
|
|
|
success = icmp_pointers[icmph->type].handler(skb);
|
|
|
|
if (success) {
|
|
consume_skb(skb);
|
|
return 0;
|
|
}
|
|
|
|
drop:
|
|
kfree_skb(skb);
|
|
return 0;
|
|
csum_error:
|
|
ICMP_INC_STATS_BH(net, ICMP_MIB_CSUMERRORS);
|
|
error:
|
|
ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
|
|
goto drop;
|
|
}
|
|
|
|
void 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;
|
|
}
|
|
|
|
if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
|
|
ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ICMP, 0);
|
|
else if (type == ICMP_REDIRECT)
|
|
ipv4_redirect(skb, net, 0, 0, IPPROTO_ICMP, 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 void __net_exit icmp_sk_exit(struct net *net)
|
|
{
|
|
int i;
|
|
|
|
for_each_possible_cpu(i)
|
|
inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i));
|
|
free_percpu(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 = alloc_percpu(struct sock *);
|
|
if (!net->ipv4.icmp_sk)
|
|
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;
|
|
|
|
*per_cpu_ptr(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(*per_cpu_ptr(net->ipv4.icmp_sk, i));
|
|
free_percpu(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);
|
|
}
|