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icmp.c
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icmp.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Internet Control Message Protocol (ICMPv6)
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <[email protected]>
*
* Based on net/ipv4/icmp.c
*
* RFC 1885
*/
/*
* 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
*/
#define pr_fmt(fmt) "IPv6: " fmt
#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/sockios.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/netfilter.h>
#include <linux/slab.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/ping.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 <net/xfrm.h>
#include <net/inet_common.h>
#include <net/dsfield.h>
#include <net/l3mdev.h>
#include <linux/uaccess.h>
/*
* The ICMP socket(s). This is the most convenient way to flow control
* our ICMP output as well as maintain a clean interface throughout
* all layers. All Socketless IP sends will soon be gone.
*
* On SMP we have one ICMP socket per-cpu.
*/
static struct sock *icmpv6_sk(struct net *net)
{
return this_cpu_read(*net->ipv6.icmp_sk);
}
static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
/* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
struct net *net = dev_net(skb->dev);
if (type == ICMPV6_PKT_TOOBIG)
ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0, sock_net_uid(net, NULL));
else if (type == NDISC_REDIRECT)
ip6_redirect(skb, net, skb->dev->ifindex, 0,
sock_net_uid(net, NULL));
if (!(type & ICMPV6_INFOMSG_MASK))
if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
ping_err(skb, offset, ntohl(info));
return 0;
}
static int icmpv6_rcv(struct sk_buff *skb);
static const struct inet6_protocol icmpv6_protocol = {
.handler = icmpv6_rcv,
.err_handler = icmpv6_err,
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};
/* Called with BH disabled */
static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
{
struct sock *sk;
sk = icmpv6_sk(net);
if (unlikely(!spin_trylock(&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.
*/
return NULL;
}
return sk;
}
static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
{
spin_unlock(&sk->sk_lock.slock);
}
/*
* 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 bool is_ineligible(const struct sk_buff *skb)
{
int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
int len = skb->len - ptr;
__u8 nexthdr = ipv6_hdr(skb)->nexthdr;
__be16 frag_off;
if (len < 0)
return true;
ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
if (ptr < 0)
return false;
if (nexthdr == IPPROTO_ICMPV6) {
u8 _type, *tp;
tp = skb_header_pointer(skb,
ptr+offsetof(struct icmp6hdr, icmp6_type),
sizeof(_type), &_type);
/* Based on RFC 8200, Section 4.5 Fragment Header, return
* false if this is a fragment packet with no icmp header info.
*/
if (!tp && frag_off != 0)
return false;
else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
return true;
}
return false;
}
static bool icmpv6_mask_allow(struct net *net, int type)
{
if (type > ICMPV6_MSG_MAX)
return true;
/* Limit if icmp type is set in ratemask. */
if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask))
return true;
return false;
}
static bool icmpv6_global_allow(struct net *net, int type)
{
if (icmpv6_mask_allow(net, type))
return true;
if (icmp_global_allow())
return true;
return false;
}
/*
* Check the ICMP output rate limit
*/
static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
struct flowi6 *fl6)
{
struct net *net = sock_net(sk);
struct dst_entry *dst;
bool res = false;
if (icmpv6_mask_allow(net, type))
return true;
/*
* 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(net, sk, fl6);
if (dst->error) {
IP6_INC_STATS(net, ip6_dst_idev(dst),
IPSTATS_MIB_OUTNOROUTES);
} else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
res = true;
} else {
struct rt6_info *rt = (struct rt6_info *)dst;
int tmo = net->ipv6.sysctl.icmpv6_time;
struct inet_peer *peer;
/* Give more bandwidth to wider prefixes. */
if (rt->rt6i_dst.plen < 128)
tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1);
res = inet_peer_xrlim_allow(peer, tmo);
if (peer)
inet_putpeer(peer);
}
dst_release(dst);
return res;
}
static bool icmpv6_rt_has_prefsrc(struct sock *sk, u8 type,
struct flowi6 *fl6)
{
struct net *net = sock_net(sk);
struct dst_entry *dst;
bool res = false;
dst = ip6_route_output(net, sk, fl6);
if (!dst->error) {
struct rt6_info *rt = (struct rt6_info *)dst;
struct in6_addr prefsrc;
rt6_get_prefsrc(rt, &prefsrc);
res = !ipv6_addr_any(&prefsrc);
}
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 bool opt_unrec(struct sk_buff *skb, __u32 offset)
{
u8 _optval, *op;
offset += skb_network_offset(skb);
op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
if (!op)
return true;
return (*op & 0xC0) == 0x80;
}
void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
struct icmp6hdr *thdr, int len)
{
struct sk_buff *skb;
struct icmp6hdr *icmp6h;
skb = skb_peek(&sk->sk_write_queue);
if (!skb)
return;
icmp6h = icmp6_hdr(skb);
memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
icmp6h->icmp6_cksum = 0;
if (skb_queue_len(&sk->sk_write_queue) == 1) {
skb->csum = csum_partial(icmp6h,
sizeof(struct icmp6hdr), skb->csum);
icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
&fl6->daddr,
len, fl6->flowi6_proto,
skb->csum);
} else {
__wsum tmp_csum = 0;
skb_queue_walk(&sk->sk_write_queue, skb) {
tmp_csum = csum_add(tmp_csum, skb->csum);
}
tmp_csum = csum_partial(icmp6h,
sizeof(struct icmp6hdr), tmp_csum);
icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
&fl6->daddr,
len, fl6->flowi6_proto,
tmp_csum);
}
ip6_push_pending_frames(sk);
}
struct icmpv6_msg {
struct sk_buff *skb;
int offset;
uint8_t type;
};
static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
{
struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
struct sk_buff *org_skb = msg->skb;
__wsum csum;
csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
to, len);
skb->csum = csum_block_add(skb->csum, csum, odd);
if (!(msg->type & ICMPV6_INFOMSG_MASK))
nf_ct_attach(skb, org_skb);
return 0;
}
#if IS_ENABLED(CONFIG_IPV6_MIP6)
static void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt)
{
struct ipv6hdr *iph = ipv6_hdr(skb);
struct ipv6_destopt_hao *hao;
struct in6_addr tmp;
int off;
if (opt->dsthao) {
off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
if (likely(off >= 0)) {
hao = (struct ipv6_destopt_hao *)
(skb_network_header(skb) + off);
tmp = iph->saddr;
iph->saddr = hao->addr;
hao->addr = tmp;
}
}
}
#else
static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {}
#endif
static struct dst_entry *icmpv6_route_lookup(struct net *net,
struct sk_buff *skb,
struct sock *sk,
struct flowi6 *fl6)
{
struct dst_entry *dst, *dst2;
struct flowi6 fl2;
int err;
err = ip6_dst_lookup(net, sk, &dst, fl6);
if (err)
return ERR_PTR(err);
/*
* We won't send icmp if the destination is known
* anycast.
*/
if (ipv6_anycast_destination(dst, &fl6->daddr)) {
net_dbg_ratelimited("icmp6_send: acast source\n");
dst_release(dst);
return ERR_PTR(-EINVAL);
}
/* No need to clone since we're just using its address. */
dst2 = dst;
dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
if (!IS_ERR(dst)) {
if (dst != dst2)
return dst;
} else {
if (PTR_ERR(dst) == -EPERM)
dst = NULL;
else
return dst;
}
err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
if (err)
goto relookup_failed;
err = ip6_dst_lookup(net, sk, &dst2, &fl2);
if (err)
goto relookup_failed;
dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
if (!IS_ERR(dst2)) {
dst_release(dst);
dst = dst2;
} else {
err = PTR_ERR(dst2);
if (err == -EPERM) {
dst_release(dst);
return dst2;
} else
goto relookup_failed;
}
relookup_failed:
if (dst)
return dst;
return ERR_PTR(err);
}
static struct net_device *icmp6_dev(const struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
/* for local traffic to local address, skb dev is the loopback
* device. Check if there is a dst attached to the skb and if so
* get the real device index. Same is needed for replies to a link
* local address on a device enslaved to an L3 master device
*/
if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) {
const struct rt6_info *rt6 = skb_rt6_info(skb);
if (rt6)
dev = rt6->rt6i_idev->dev;
}
return dev;
}
static int icmp6_iif(const struct sk_buff *skb)
{
return icmp6_dev(skb)->ifindex;
}
/*
* Send an ICMP message in response to a packet in error
*/
void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
const struct in6_addr *force_saddr,
const struct inet6_skb_parm *parm)
{
struct inet6_dev *idev = NULL;
struct ipv6hdr *hdr = ipv6_hdr(skb);
struct sock *sk;
struct net *net;
struct ipv6_pinfo *np;
const struct in6_addr *saddr = NULL;
struct dst_entry *dst;
struct icmp6hdr tmp_hdr;
struct flowi6 fl6;
struct icmpv6_msg msg;
struct ipcm6_cookie ipc6;
int iif = 0;
int addr_type = 0;
int len;
u32 mark;
if ((u8 *)hdr < skb->head ||
(skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
return;
if (!skb->dev)
return;
net = dev_net(skb->dev);
mark = IP6_REPLY_MARK(net, skb->mark);
/*
* Make sure we respect the rules
* i.e. RFC 1885 2.4(e)
* Rule (e.1) is enforced by not using icmp6_send
* in any code that processes icmp errors.
*/
addr_type = ipv6_addr_type(&hdr->daddr);
if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
saddr = &hdr->daddr;
/*
* Dest addr check
*/
if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
if (type != ICMPV6_PKT_TOOBIG &&
!(type == ICMPV6_PARAMPROB &&
code == ICMPV6_UNK_OPTION &&
(opt_unrec(skb, info))))
return;
saddr = NULL;
}
addr_type = ipv6_addr_type(&hdr->saddr);
/*
* Source addr check
*/
if (__ipv6_addr_needs_scope_id(addr_type)) {
iif = icmp6_iif(skb);
} else {
/*
* The source device is used for looking up which routing table
* to use for sending an ICMP error.
*/
iif = l3mdev_master_ifindex(skb->dev);
}
/*
* Must not send error if the source does not uniquely
* identify a single node (RFC2463 Section 2.4).
* We check unspecified / multicast addresses here,
* and anycast addresses will be checked later.
*/
if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
&hdr->saddr, &hdr->daddr);
return;
}
/*
* Never answer to a ICMP packet.
*/
if (is_ineligible(skb)) {
net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
&hdr->saddr, &hdr->daddr);
return;
}
/* Needed by both icmp_global_allow and icmpv6_xmit_lock */
local_bh_disable();
/* Check global sysctl_icmp_msgs_per_sec ratelimit */
if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type))
goto out_bh_enable;
mip6_addr_swap(skb, parm);
sk = icmpv6_xmit_lock(net);
if (!sk)
goto out_bh_enable;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_ICMPV6;
fl6.daddr = hdr->saddr;
if (force_saddr)
saddr = force_saddr;
if (saddr) {
fl6.saddr = *saddr;
} else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) {
/* select a more meaningful saddr from input if */
struct net_device *in_netdev;
in_netdev = dev_get_by_index(net, parm->iif);
if (in_netdev) {
ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr,
inet6_sk(sk)->srcprefs,
&fl6.saddr);
dev_put(in_netdev);
}
}
fl6.flowi6_mark = mark;
fl6.flowi6_oif = iif;
fl6.fl6_icmp_type = type;
fl6.fl6_icmp_code = code;
fl6.flowi6_uid = sock_net_uid(net, NULL);
fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
np = inet6_sk(sk);
if (!icmpv6_xrlim_allow(sk, type, &fl6))
goto out;
tmp_hdr.icmp6_type = type;
tmp_hdr.icmp6_code = code;
tmp_hdr.icmp6_cksum = 0;
tmp_hdr.icmp6_pointer = htonl(info);
if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
fl6.flowi6_oif = np->mcast_oif;
else if (!fl6.flowi6_oif)
fl6.flowi6_oif = np->ucast_oif;
ipcm6_init_sk(&ipc6, np);
ipc6.sockc.mark = mark;
fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
dst = icmpv6_route_lookup(net, skb, sk, &fl6);
if (IS_ERR(dst))
goto out;
ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
msg.skb = skb;
msg.offset = skb_network_offset(skb);
msg.type = type;
len = skb->len - msg.offset;
len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
if (len < 0) {
net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
&hdr->saddr, &hdr->daddr);
goto out_dst_release;
}
rcu_read_lock();
idev = __in6_dev_get(skb->dev);
if (ip6_append_data(sk, icmpv6_getfrag, &msg,
len + sizeof(struct icmp6hdr),
sizeof(struct icmp6hdr),
&ipc6, &fl6, (struct rt6_info *)dst,
MSG_DONTWAIT)) {
ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
ip6_flush_pending_frames(sk);
} else {
icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
len + sizeof(struct icmp6hdr));
}
rcu_read_unlock();
out_dst_release:
dst_release(dst);
out:
icmpv6_xmit_unlock(sk);
out_bh_enable:
local_bh_enable();
}
EXPORT_SYMBOL(icmp6_send);
/* Slightly more convenient version of icmp6_send.
*/
void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
{
icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb));
kfree_skb(skb);
}
/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
* if sufficient data bytes are available
* @nhs is the size of the tunnel header(s) :
* Either an IPv4 header for SIT encap
* an IPv4 header + GRE header for GRE encap
*/
int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
unsigned int data_len)
{
struct in6_addr temp_saddr;
struct rt6_info *rt;
struct sk_buff *skb2;
u32 info = 0;
if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
return 1;
/* RFC 4884 (partial) support for ICMP extensions */
if (data_len < 128 || (data_len & 7) || skb->len < data_len)
data_len = 0;
skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
if (!skb2)
return 1;
skb_dst_drop(skb2);
skb_pull(skb2, nhs);
skb_reset_network_header(skb2);
rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0,
skb, 0);
if (rt && rt->dst.dev)
skb2->dev = rt->dst.dev;
ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
if (data_len) {
/* RFC 4884 (partial) support :
* insert 0 padding at the end, before the extensions
*/
__skb_push(skb2, nhs);
skb_reset_network_header(skb2);
memmove(skb2->data, skb2->data + nhs, data_len - nhs);
memset(skb2->data + data_len - nhs, 0, nhs);
/* RFC 4884 4.5 : Length is measured in 64-bit words,
* and stored in reserved[0]
*/
info = (data_len/8) << 24;
}
if (type == ICMP_TIME_EXCEEDED)
icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
info, &temp_saddr, IP6CB(skb2));
else
icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
info, &temp_saddr, IP6CB(skb2));
if (rt)
ip6_rt_put(rt);
kfree_skb(skb2);
return 0;
}
EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
static void icmpv6_echo_reply(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
struct sock *sk;
struct inet6_dev *idev;
struct ipv6_pinfo *np;
const struct in6_addr *saddr = NULL;
struct icmp6hdr *icmph = icmp6_hdr(skb);
struct icmp6hdr tmp_hdr;
struct flowi6 fl6;
struct icmpv6_msg msg;
struct dst_entry *dst;
struct ipcm6_cookie ipc6;
u32 mark = IP6_REPLY_MARK(net, skb->mark);
bool acast;
if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&
net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
return;
saddr = &ipv6_hdr(skb)->daddr;
acast = ipv6_anycast_destination(skb_dst(skb), saddr);
if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast)
return;
if (!ipv6_unicast_destination(skb) &&
!(net->ipv6.sysctl.anycast_src_echo_reply && acast))
saddr = NULL;
memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
memset(&fl6, 0, sizeof(fl6));
if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb));
fl6.flowi6_proto = IPPROTO_ICMPV6;
fl6.daddr = ipv6_hdr(skb)->saddr;
if (saddr)
fl6.saddr = *saddr;
fl6.flowi6_oif = icmp6_iif(skb);
fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
fl6.flowi6_mark = mark;
fl6.flowi6_uid = sock_net_uid(net, NULL);
security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
local_bh_disable();
sk = icmpv6_xmit_lock(net);
if (!sk)
goto out_bh_enable;
np = inet6_sk(sk);
if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
fl6.flowi6_oif = np->mcast_oif;
else if (!fl6.flowi6_oif)
fl6.flowi6_oif = np->ucast_oif;
if (ip6_dst_lookup(net, sk, &dst, &fl6))
goto out;
dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
if (IS_ERR(dst))
goto out;
/* Check the ratelimit */
if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) ||
!icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6))
goto out_dst_release;
idev = __in6_dev_get(skb->dev);
msg.skb = skb;
msg.offset = 0;
msg.type = ICMPV6_ECHO_REPLY;
ipcm6_init_sk(&ipc6, np);
ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
ipc6.sockc.mark = mark;
if (ip6_append_data(sk, icmpv6_getfrag, &msg,
skb->len + sizeof(struct icmp6hdr),
sizeof(struct icmp6hdr), &ipc6, &fl6,
(struct rt6_info *)dst, MSG_DONTWAIT)) {
__ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
ip6_flush_pending_frames(sk);
} else {
icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
skb->len + sizeof(struct icmp6hdr));
}
out_dst_release:
dst_release(dst);
out:
icmpv6_xmit_unlock(sk);
out_bh_enable:
local_bh_enable();
}
void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
{
const struct inet6_protocol *ipprot;
int inner_offset;
__be16 frag_off;
u8 nexthdr;
struct net *net = dev_net(skb->dev);
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto out;
nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
if (ipv6_ext_hdr(nexthdr)) {
/* now skip over extension headers */
inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
&nexthdr, &frag_off);
if (inner_offset < 0)
goto out;
} else {
inner_offset = sizeof(struct ipv6hdr);
}
/* Checkin header including 8 bytes of inner protocol header. */
if (!pskb_may_pull(skb, inner_offset+8))
goto out;
/* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
Without this we will not able f.e. to make source routed
pmtu discovery.
Corresponding argument (opt) to notifiers is already added.
--ANK (980726)
*/
ipprot = rcu_dereference(inet6_protos[nexthdr]);
if (ipprot && ipprot->err_handler)
ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
return;
out:
__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
}
/*
* Handle icmp messages
*/
static int icmpv6_rcv(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
struct net_device *dev = icmp6_dev(skb);
struct inet6_dev *idev = __in6_dev_get(dev);
const struct in6_addr *saddr, *daddr;
struct icmp6hdr *hdr;
u8 type;
bool success = false;
if (!xfrm6_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_no_count;
if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
goto drop_no_count;
nh = skb_network_offset(skb);
skb_set_network_header(skb, sizeof(*hdr));
if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
goto drop_no_count;
skb_set_network_header(skb, nh);
}
__ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS);
saddr = &ipv6_hdr(skb)->saddr;
daddr = &ipv6_hdr(skb)->daddr;
if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
saddr, daddr);
goto csum_error;
}
if (!pskb_pull(skb, sizeof(*hdr)))
goto discard_it;
hdr = icmp6_hdr(skb);
type = hdr->icmp6_type;
ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type);
switch (type) {
case ICMPV6_ECHO_REQUEST:
if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)
icmpv6_echo_reply(skb);
break;
case ICMPV6_ECHO_REPLY:
success = ping_rcv(skb);
break;
case ICMPV6_EXT_ECHO_REPLY:
success = ping_rcv(skb);
break;
case ICMPV6_PKT_TOOBIG:
/* BUGGG_FUTURE: if packet contains rthdr, we cannot update
standard destination cache. Seems, only "advanced"
destination cache will allow to solve this problem
--ANK (980726)
*/
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto discard_it;
hdr = icmp6_hdr(skb);
/* to notify */
fallthrough;
case ICMPV6_DEST_UNREACH:
case ICMPV6_TIME_EXCEED:
case ICMPV6_PARAMPROB:
icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
break;
case NDISC_ROUTER_SOLICITATION:
case NDISC_ROUTER_ADVERTISEMENT:
case NDISC_NEIGHBOUR_SOLICITATION:
case NDISC_NEIGHBOUR_ADVERTISEMENT:
case NDISC_REDIRECT:
ndisc_rcv(skb);
break;
case ICMPV6_MGM_QUERY:
igmp6_event_query(skb);
return 0;
case ICMPV6_MGM_REPORT:
igmp6_event_report(skb);
return 0;
case ICMPV6_MGM_REDUCTION:
case ICMPV6_NI_QUERY:
case ICMPV6_NI_REPLY:
case ICMPV6_MLD2_REPORT:
case ICMPV6_DHAAD_REQUEST:
case ICMPV6_DHAAD_REPLY:
case ICMPV6_MOBILE_PREFIX_SOL:
case ICMPV6_MOBILE_PREFIX_ADV:
break;
default:
/* informational */
if (type & ICMPV6_INFOMSG_MASK)
break;
net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
saddr, daddr);
/*
* error of unknown type.
* must pass to upper level
*/
icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
}
/* until the v6 path can be better sorted assume failure and
* preserve the status quo behaviour for the rest of the paths to here
*/
if (success)
consume_skb(skb);
else
kfree_skb(skb);
return 0;
csum_error:
__ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
discard_it:
__ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
drop_no_count:
kfree_skb(skb);
return 0;
}