Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1510 insertions, 0 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
new file mode 100644
index 0000000000..b8607763d1
--- /dev/null
+++ b/net/ipv4/icmp.c
@@ -0,0 +1,1510 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	NET3:	Implementation of the ICMP protocol layer.
+ *
+ *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
+ *
+ *	Some of the function names and the icmp unreach table for this
+ *	module were derived from [icmp.c 1.0.11 06/02/93] by
+ *	Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
+ *	Other than that this module is a complete rewrite.
+ *
+ *	Fixes:
+ *	Clemens Fruhwirth	:	introduce global icmp rate limiting
+ *					with icmp type masking ability instead
+ *					of broken per type icmp timeouts.
+ *		Mike Shaver	:	RFC1122 checks.
+ *		Alan Cox	:	Multicast ping reply as self.
+ *		Alan Cox	:	Fix atomicity lockup in ip_build_xmit
+ *					call.
+ *		Alan Cox	:	Added 216,128 byte paths to the MTU
+ *					code.
+ *		Martin Mares	:	RFC1812 checks.
+ *		Martin Mares	:	Can be configured to follow redirects
+ *					if acting as a router _without_ a
+ *					routing protocol (RFC 1812).
+ *		Martin Mares	:	Echo requests may be configured to
+ *					be ignored (RFC 1812).
+ *		Martin Mares	:	Limitation of ICMP error message
+ *					transmit rate (RFC 1812).
+ *		Martin Mares	:	TOS and Precedence set correctly
+ *					(RFC 1812).
+ *		Martin Mares	:	Now copying as much data from the
+ *					original packet as we can without
+ *					exceeding 576 bytes (RFC 1812).
+ *	Willy Konynenberg	:	Transparent proxying support.
+ *		Keith Owens	:	RFC1191 correction for 4.2BSD based
+ *					path MTU bug.
+ *		Thomas Quinot	:	ICMP Dest Unreach codes up to 15 are
+ *					valid (RFC 1812).
+ *		Andi Kleen	:	Check all packet lengths properly
+ *					and moved all kfree_skb() up to
+ *					icmp_rcv.
+ *		Andi Kleen	:	Move the rate limit bookkeeping
+ *					into the dest entry and use a token
+ *					bucket filter (thanks to ANK). Make
+ *					the rates sysctl configurable.
+ *		Yu Tianli	:	Fixed two ugly bugs in icmp_send
+ *					- IP option length was accounted wrongly
+ *					- ICMP header length was not accounted
+ *					  at all.
+ *              Tristan Greaves :       Added sysctl option to ignore bogus
+ *              			broadcast responses from broken routers.
+ *
+ * To Fix:
+ *
+ *	- Should use skb_pull() instead of all the manual checking.
+ *	  This would also greatly simply some upper layer error handlers. --AK
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/fcntl.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/inetdevice.h>
+#include <linux/netdevice.h>
+#include <linux/string.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/slab.h>
+#include <net/snmp.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <net/protocol.h>
+#include <net/icmp.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+#include <net/raw.h>
+#include <net/ping.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <net/checksum.h>
+#include <net/xfrm.h>
+#include <net/inet_common.h>
+#include <net/ip_fib.h>
+#include <net/l3mdev.h>
+
+/*
+ *	Build xmit assembly blocks
+ */
+
+struct icmp_bxm {
+	struct sk_buff *skb;
+	int offset;
+	int data_len;
+
+	struct {
+		struct icmphdr icmph;
+		__be32	       times[3];
+	} data;
+	int head_len;
+	struct ip_options_data replyopts;
+};
+
+/* An array of errno for error messages from dest unreach. */
+/* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
+
+const struct icmp_err icmp_err_convert[] = {
+	{
+		.errno = ENETUNREACH,	/* ICMP_NET_UNREACH */
+		.fatal = 0,
+	},
+	{
+		.errno = EHOSTUNREACH,	/* ICMP_HOST_UNREACH */
+		.fatal = 0,
+	},
+	{
+		.errno = ENOPROTOOPT	/* ICMP_PROT_UNREACH */,
+		.fatal = 1,
+	},
+	{
+		.errno = ECONNREFUSED,	/* ICMP_PORT_UNREACH */
+		.fatal = 1,
+	},
+	{
+		.errno = EMSGSIZE,	/* ICMP_FRAG_NEEDED */
+		.fatal = 0,
+	},
+	{
+		.errno = EOPNOTSUPP,	/* ICMP_SR_FAILED */
+		.fatal = 0,
+	},
+	{
+		.errno = ENETUNREACH,	/* ICMP_NET_UNKNOWN */
+		.fatal = 1,
+	},
+	{
+		.errno = EHOSTDOWN,	/* ICMP_HOST_UNKNOWN */
+		.fatal = 1,
+	},
+	{
+		.errno = ENONET,	/* ICMP_HOST_ISOLATED */
+		.fatal = 1,
+	},
+	{
+		.errno = ENETUNREACH,	/* ICMP_NET_ANO	*/
+		.fatal = 1,
+	},
+	{
+		.errno = EHOSTUNREACH,	/* ICMP_HOST_ANO */
+		.fatal = 1,
+	},
+	{
+		.errno = ENETUNREACH,	/* ICMP_NET_UNR_TOS */
+		.fatal = 0,
+	},
+	{
+		.errno = EHOSTUNREACH,	/* ICMP_HOST_UNR_TOS */
+		.fatal = 0,
+	},
+	{
+		.errno = EHOSTUNREACH,	/* ICMP_PKT_FILTERED */
+		.fatal = 1,
+	},
+	{
+		.errno = EHOSTUNREACH,	/* ICMP_PREC_VIOLATION */
+		.fatal = 1,
+	},
+	{
+		.errno = EHOSTUNREACH,	/* ICMP_PREC_CUTOFF */
+		.fatal = 1,
+	},
+};
+EXPORT_SYMBOL(icmp_err_convert);
+
+/*
+ *	ICMP control array. This specifies what to do with each ICMP.
+ */
+
+struct icmp_control {
+	enum skb_drop_reason (*handler)(struct sk_buff *skb);
+	short   error;		/* This ICMP is classed as an error message */
+};
+
+static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
+
+static DEFINE_PER_CPU(struct sock *, ipv4_icmp_sk);
+
+/* Called with BH disabled */
+static inline struct sock *icmp_xmit_lock(struct net *net)
+{
+	struct sock *sk;
+
+	sk = this_cpu_read(ipv4_icmp_sk);
+
+	if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
+		/* This can happen if the output path signals a
+		 * dst_link_failure() for an outgoing ICMP packet.
+		 */
+		return NULL;
+	}
+	sock_net_set(sk, net);
+	return sk;
+}
+
+static inline void icmp_xmit_unlock(struct sock *sk)
+{
+	sock_net_set(sk, &init_net);
+	spin_unlock(&sk->sk_lock.slock);
+}
+
+int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
+int sysctl_icmp_msgs_burst __read_mostly = 50;
+
+static struct {
+	spinlock_t	lock;
+	u32		credit;
+	u32		stamp;
+} icmp_global = {
+	.lock		= __SPIN_LOCK_UNLOCKED(icmp_global.lock),
+};
+
+/**
+ * icmp_global_allow - Are we allowed to send one more ICMP message ?
+ *
+ * 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
+ */
+bool icmp_global_allow(void)
+{
+	u32 credit, delta, incr = 0, now = (u32)jiffies;
+	bool rc = false;
+
+	/* Check if token bucket is empty and cannot be refilled
+	 * without taking the spinlock. The READ_ONCE() are paired
+	 * with the following WRITE_ONCE() in this same function.
+	 */
+	if (!READ_ONCE(icmp_global.credit)) {
+		delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ);
+		if (delta < HZ / 50)
+			return false;
+	}
+
+	spin_lock(&icmp_global.lock);
+	delta = min_t(u32, now - icmp_global.stamp, HZ);
+	if (delta >= HZ / 50) {
+		incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ;
+		if (incr)
+			WRITE_ONCE(icmp_global.stamp, now);
+	}
+	credit = min_t(u32, icmp_global.credit + incr,
+		       READ_ONCE(sysctl_icmp_msgs_burst));
+	if (credit) {
+		/* We want to use a credit of one in average, but need to randomize
+		 * it for security reasons.
+		 */
+		credit = max_t(int, credit - get_random_u32_below(3), 0);
+		rc = true;
+	}
+	WRITE_ONCE(icmp_global.credit, credit);
+	spin_unlock(&icmp_global.lock);
+	return rc;
+}
+EXPORT_SYMBOL(icmp_global_allow);
+
+static bool icmpv4_mask_allow(struct net *net, int type, int code)
+{
+	if (type > NR_ICMP_TYPES)
+		return true;
+
+	/* Don't limit PMTU discovery. */
+	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
+		return true;
+
+	/* Limit if icmp type is enabled in ratemask. */
+	if (!((1 << type) & READ_ONCE(net->ipv4.sysctl_icmp_ratemask)))
+		return true;
+
+	return false;
+}
+
+static bool icmpv4_global_allow(struct net *net, int type, int code)
+{
+	if (icmpv4_mask_allow(net, type, code))
+		return true;
+
+	if (icmp_global_allow())
+		return true;
+
+	__ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL);
+	return false;
+}
+
+/*
+ *	Send an ICMP frame.
+ */
+
+static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
+			       struct flowi4 *fl4, int type, int code)
+{
+	struct dst_entry *dst = &rt->dst;
+	struct inet_peer *peer;
+	bool rc = true;
+	int vif;
+
+	if (icmpv4_mask_allow(net, type, code))
+		goto out;
+
+	/* No rate limit on loopback */
+	if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
+		goto out;
+
+	vif = l3mdev_master_ifindex(dst->dev);
+	peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
+	rc = inet_peer_xrlim_allow(peer,
+				   READ_ONCE(net->ipv4.sysctl_icmp_ratelimit));
+	if (peer)
+		inet_putpeer(peer);
+out:
+	if (!rc)
+		__ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST);
+	return rc;
+}
+
+/*
+ *	Maintain the counters used in the SNMP statistics for outgoing ICMP
+ */
+void icmp_out_count(struct net *net, unsigned char type)
+{
+	ICMPMSGOUT_INC_STATS(net, type);
+	ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
+}
+
+/*
+ *	Checksum each fragment, and on the first include the headers and final
+ *	checksum.
+ */
+static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
+			  struct sk_buff *skb)
+{
+	struct icmp_bxm *icmp_param = from;
+	__wsum csum;
+
+	csum = skb_copy_and_csum_bits(icmp_param->skb,
+				      icmp_param->offset + offset,
+				      to, len);
+
+	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 sock *sk,
+			    struct icmp_bxm *icmp_param,
+			    struct flowi4 *fl4,
+			    struct ipcm_cookie *ipc, struct rtable **rt)
+{
+	struct sk_buff *skb;
+
+	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(sk, 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) &&
+		    READ_ONCE(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);
+	/* Guard against tiny mtu. We need to include at least one
+	 * IP network header for this message to make any sense.
+	 */
+	if (room <= (int)sizeof(struct iphdr))
+		goto ende;
+
+	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(sk, &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 enum skb_drop_reason icmp_unreach(struct sk_buff *skb)
+{
+	enum skb_drop_reason reason = SKB_NOT_DROPPED_YET;
+	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. */
+		reason = SKB_DROP_REASON_IP_INHDR;
+		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 (READ_ONCE(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 (!READ_ONCE(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 reason;
+out_err:
+	__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
+	return reason ?: SKB_DROP_REASON_NOT_SPECIFIED;
+}
+
+
+/*
+ *	Handle ICMP_REDIRECT.
+ */
+
+static enum skb_drop_reason icmp_redirect(struct sk_buff *skb)
+{
+	if (skb->len < sizeof(struct iphdr)) {
+		__ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
+		return SKB_DROP_REASON_PKT_TOO_SMALL;
+	}
+
+	if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
+		/* there aught to be a stat */
+		return SKB_DROP_REASON_NOMEM;
+	}
+
+	icmp_socket_deliver(skb, ntohl(icmp_hdr(skb)->un.gateway));
+	return SKB_NOT_DROPPED_YET;
+}
+
+/*
+ *	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 enum skb_drop_reason 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 (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all))
+		return SKB_NOT_DROPPED_YET;
+
+	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 SKB_NOT_DROPPED_YET;
+
+	icmp_reply(&icmp_param, skb);
+	return SKB_NOT_DROPPED_YET;
+}
+
+/*	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 (!READ_ONCE(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 enum skb_drop_reason 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 SKB_NOT_DROPPED_YET;
+
+out_err:
+	__ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
+	return SKB_DROP_REASON_PKT_TOO_SMALL;
+}
+
+static enum skb_drop_reason icmp_discard(struct sk_buff *skb)
+{
+	/* pretend it was a success */
+	return SKB_NOT_DROPPED_YET;
+}
+
+/*
+ *	Deal with incoming ICMP packets.
+ */
+int icmp_rcv(struct sk_buff *skb)
+{
+	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
+	struct rtable *rt = skb_rtable(skb);
+	struct net *net = dev_net(rt->dst.dev);
+	struct icmphdr *icmph;
+
+	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)) {
+			reason = SKB_DROP_REASON_XFRM_POLICY;
+			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)) {
+			reason = SKB_DROP_REASON_XFRM_POLICY;
+			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.
+		 */
+		reason = icmp_echo(skb);
+		goto reason_check;
+	}
+
+	if (icmph->type == ICMP_EXT_ECHOREPLY) {
+		reason = ping_rcv(skb);
+		goto reason_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) {
+		reason = SKB_DROP_REASON_UNHANDLED_PROTO;
+		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) &&
+		    READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_broadcasts)) {
+			reason = SKB_DROP_REASON_INVALID_PROTO;
+			goto error;
+		}
+		if (icmph->type != ICMP_ECHO &&
+		    icmph->type != ICMP_TIMESTAMP &&
+		    icmph->type != ICMP_ADDRESS &&
+		    icmph->type != ICMP_ADDRESSREPLY) {
+			reason = SKB_DROP_REASON_INVALID_PROTO;
+			goto error;
+		}
+	}
+
+	reason = icmp_pointers[icmph->type].handler(skb);
+reason_check:
+	if (!reason)  {
+		consume_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+drop:
+	kfree_skb_reason(skb, reason);
+	return NET_RX_DROP;
+csum_error:
+	reason = SKB_DROP_REASON_ICMP_CSUM;
+	__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 int __net_init icmp_sk_init(struct net *net)
+{
+	/* 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;
+}
+
+static struct pernet_operations __net_initdata icmp_sk_ops = {
+       .init = icmp_sk_init,
+};
+
+int __init icmp_init(void)
+{
+	int err, i;
+
+	for_each_possible_cpu(i) {
+		struct sock *sk;
+
+		err = inet_ctl_sock_create(&sk, PF_INET,
+					   SOCK_RAW, IPPROTO_ICMP, &init_net);
+		if (err < 0)
+			return err;
+
+		per_cpu(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;
+	}
+	return register_pernet_subsys(&icmp_sk_ops);
+}