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1516 lines
37 KiB
1516 lines
37 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* NET3: Implementation of the ICMP protocol layer. |
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* |
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* Alan Cox, <[email protected]> |
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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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|
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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 <linux/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/l3mdev.h> |
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|
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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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|
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static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1]; |
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|
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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_read(*net->ipv4.icmp_sk); |
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} |
|
|
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/* Called with BH disabled */ |
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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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|
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sk = icmp_sk(net); |
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|
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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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return NULL; |
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} |
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return sk; |
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} |
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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(&sk->sk_lock.slock); |
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} |
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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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|
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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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/** |
|
* icmp_global_allow - Are we allowed to send one more ICMP message ? |
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* |
|
* 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 |
|
*/ |
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bool icmp_global_allow(void) |
|
{ |
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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. The READ_ONCE() are paired |
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* with the following WRITE_ONCE() in this same function. |
|
*/ |
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if (!READ_ONCE(icmp_global.credit)) { |
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delta = min_t(u32, now - READ_ONCE(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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|
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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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WRITE_ONCE(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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/* We want to use a credit of one in average, but need to randomize |
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* it for security reasons. |
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*/ |
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credit = max_t(int, credit - prandom_u32_max(3), 0); |
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rc = true; |
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} |
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WRITE_ONCE(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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static bool icmpv4_mask_allow(struct net *net, int type, int code) |
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{ |
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if (type > NR_ICMP_TYPES) |
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return true; |
|
|
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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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return true; |
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|
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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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return true; |
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|
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return false; |
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} |
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|
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static bool icmpv4_global_allow(struct net *net, int type, int code) |
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{ |
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if (icmpv4_mask_allow(net, type, code)) |
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return true; |
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|
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if (icmp_global_allow()) |
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return true; |
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|
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return false; |
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} |
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|
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/* |
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* Send an ICMP frame. |
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*/ |
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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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struct inet_peer *peer; |
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bool rc = true; |
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int vif; |
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|
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if (icmpv4_mask_allow(net, type, code)) |
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goto out; |
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|
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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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|
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vif = l3mdev_master_ifindex(dst->dev); |
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peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1); |
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rc = inet_peer_xrlim_allow(peer, net->ipv4.sysctl_icmp_ratelimit); |
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if (peer) |
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inet_putpeer(peer); |
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out: |
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return rc; |
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} |
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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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/* |
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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, |
|
icmp_param->offset + offset, |
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to, len); |
|
|
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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, |
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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(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(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) && |
|
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); |
|
|
|
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(&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 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; |
|
|
|
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 (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 (!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(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(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, ntohl(icmp_hdr(skb)->un.gateway)); |
|
return true; |
|
} |
|
|
|
/* |
|
* 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 bool 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 (net->ipv4.sysctl_icmp_echo_ignore_all) |
|
return true; |
|
|
|
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 true; |
|
|
|
icmp_reply(&icmp_param, skb); |
|
return true; |
|
} |
|
|
|
/* 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 (!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 bool 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 true; |
|
|
|
out_err: |
|
__ICMP_INC_STATS(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(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. |
|
*/ |
|
success = icmp_echo(skb); |
|
goto success_check; |
|
} |
|
|
|
if (icmph->type == ICMP_EXT_ECHOREPLY) { |
|
success = ping_rcv(skb); |
|
goto success_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) |
|
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); |
|
success_check: |
|
if (success) { |
|
consume_skb(skb); |
|
return NET_RX_SUCCESS; |
|
} |
|
|
|
drop: |
|
kfree_skb(skb); |
|
return NET_RX_DROP; |
|
csum_error: |
|
__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 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_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; |
|
|
|
fail: |
|
icmp_sk_exit(net); |
|
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); |
|
}
|
|
|