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/*
* Internet Control Message Protocol (ICMPv6)
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* $Id: icmp.c,v 1.38 2002/02/08 03:57:19 davem Exp $
*
* Based on net/ipv4/icmp.c
*
* RFC 1885
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
/*
* Changes:
*
* Andi Kleen : exception handling
* Andi Kleen add rate limits. never reply to a icmp.
* add more length checks and other fixes.
* yoshfuji : ensure to sent parameter problem for
* fragments.
* YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
* Randy Dunlap and
* YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
* Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/netfilter.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/icmpv6.h>
#include <net/ip.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/protocol.h>
#include <net/raw.h>
#include <net/rawv6.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/icmp.h>
#include <asm/uaccess.h>
#include <asm/system.h>
DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics) __read_mostly;
/*
* The ICMP socket(s). This is the most convenient way to flow control
* our ICMP output as well as maintain a clean interface throughout
* all layers. All Socketless IP sends will soon be gone.
*
* On SMP we have one ICMP socket per-cpu.
*/
static DEFINE_PER_CPU(struct socket *, __icmpv6_socket) = NULL;
#define icmpv6_socket __get_cpu_var(__icmpv6_socket)
static int icmpv6_rcv(struct sk_buff **pskb);
static struct inet6_protocol icmpv6_protocol = {
.handler = icmpv6_rcv,
.flags = INET6_PROTO_FINAL,
};
static __inline__ int icmpv6_xmit_lock(void)
{
local_bh_disable();
if (unlikely(!spin_trylock(&icmpv6_socket->sk->sk_lock.slock))) {
/* This can happen if the output path (f.e. SIT or
* ip6ip6 tunnel) signals dst_link_failure() for an
* outgoing ICMP6 packet.
*/
local_bh_enable();
return 1;
}
return 0;
}
static __inline__ void icmpv6_xmit_unlock(void)
{
spin_unlock_bh(&icmpv6_socket->sk->sk_lock.slock);
}
/*
* Slightly more convenient version of icmpv6_send.
*/
void icmpv6_param_prob(struct sk_buff *skb, int code, int pos)
{
icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
kfree_skb(skb);
}
/*
* Figure out, may we reply to this packet with icmp error.
*
* We do not reply, if:
* - it was icmp error message.
* - it is truncated, so that it is known, that protocol is ICMPV6
* (i.e. in the middle of some exthdr)
*
* --ANK (980726)
*/
static int is_ineligible(struct sk_buff *skb)
{
int ptr = (u8*)(skb->nh.ipv6h+1) - skb->data;
int len = skb->len - ptr;
__u8 nexthdr = skb->nh.ipv6h->nexthdr;
if (len < 0)
return 1;
ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr);
if (ptr < 0)
return 0;
if (nexthdr == IPPROTO_ICMPV6) {
u8 _type, *tp;
tp = skb_header_pointer(skb,
ptr+offsetof(struct icmp6hdr, icmp6_type),
sizeof(_type), &_type);
if (tp == NULL ||
!(*tp & ICMPV6_INFOMSG_MASK))
return 1;
}
return 0;
}
static int sysctl_icmpv6_time = 1*HZ;
/*
* Check the ICMP output rate limit
*/
static inline int icmpv6_xrlim_allow(struct sock *sk, int type,
struct flowi *fl)
{
struct dst_entry *dst;
int res = 0;
/* Informational messages are not limited. */
if (type & ICMPV6_INFOMSG_MASK)
return 1;
/* Do not limit pmtu discovery, it would break it. */
if (type == ICMPV6_PKT_TOOBIG)
return 1;
/*
* Look up the output route.
* XXX: perhaps the expire for routing entries cloned by
* this lookup should be more aggressive (not longer than timeout).
*/
dst = ip6_route_output(sk, fl);
if (dst->error) {
IP6_INC_STATS(IPSTATS_MIB_OUTNOROUTES);
} else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
res = 1;
} else {
struct rt6_info *rt = (struct rt6_info *)dst;
int tmo = sysctl_icmpv6_time;
/* Give more bandwidth to wider prefixes. */
if (rt->rt6i_dst.plen < 128)
tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
res = xrlim_allow(dst, tmo);
}
dst_release(dst);
return res;
}
/*
* an inline helper for the "simple" if statement below
* checks if parameter problem report is caused by an
* unrecognized IPv6 option that has the Option Type
* highest-order two bits set to 10
*/
static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
{
u8 _optval, *op;
offset += skb->nh.raw - skb->data;
op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
if (op == NULL)
return 1;
return (*op & 0xC0) == 0x80;
}
static int icmpv6_push_pending_frames(struct sock *sk, struct flowi *fl, struct icmp6hdr *thdr, int len)
{
struct sk_buff *skb;
struct icmp6hdr *icmp6h;
int err = 0;
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