cregit-Linux how code gets into the kernel

Release 4.11 net/ipv6/icmp.c

Directory: net/ipv6
/*
 *      Internet Control Message Protocol (ICMPv6)
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *
 *      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
 */


#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 inline struct sock *icmpv6_sk(struct net *net)
{
	return net->ipv6.icmp_sk[smp_processor_id()];
}


Contributors
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Denis V. Lunev2496.00%375.00%


David S. Miller14.00%125.00%


Total25100.00%4100.00%






static void 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, 0, 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));
}


Contributors
PersonTokensPropCommitsCommitProp
Steffen Klassert7653.15%120.00%


Lorenzo Colitti5941.26%240.00%


Duan Jiong53.50%120.00%


Hannes Frederic Sowa32.10%120.00%


Total143100.00%5100.00%



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);
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)1254.55%116.67%


Denis V. Lunev627.27%233.33%


David S. Miller29.09%116.67%


Jesper Dangaard Brouer14.55%116.67%


Arnaldo Carvalho de Melo14.55%116.67%


Total22100.00%6100.00%



/*
 * 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);
		if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
			return true;
	}
	return false;
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)5739.31%222.22%


Linus Torvalds4933.79%111.11%


David S. Miller1913.10%111.11%


Jesse Gross64.14%111.11%


Arnaldo Carvalho de Melo64.14%111.11%


Eric Dumazet64.14%111.11%


Ian Morris10.69%111.11%


Hideaki Yoshifuji / 吉藤英明10.69%111.11%


Total145100.00%9100.00%






static bool icmpv6_mask_allow(int type)
{
	/* Informational messages are not limited. */
	if (type & ICMPV6_INFOMSG_MASK)
		return true;

	/* Do not limit pmtu discovery, it would break it. */
	if (type == ICMPV6_PKT_TOOBIG)
		return true;

	return false;
}


Contributors
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Jesper Dangaard Brouer32100.00%1100.00%


Total32100.00%1100.00%






static bool icmpv6_global_allow(int type)
{
	if (icmpv6_mask_allow(type))
		return true;

	if (icmp_global_allow())
		return true;

	return false;
}


Contributors
PersonTokensPropCommitsCommitProp
Jesper Dangaard Brouer30100.00%1100.00%


Total30100.00%1100.00%



/*
 * 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(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;
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)12862.14%420.00%


David S. Miller3516.99%420.00%


Hideaki Yoshifuji / 吉藤英明104.85%420.00%


Benjamin Thery94.37%15.00%


Jesper Dangaard Brouer83.88%15.00%


Daniel Lezcano62.91%210.00%


Eric Dumazet52.43%15.00%


Martin KaFai Lau20.97%15.00%


Denis V. Lunev20.97%15.00%


Brian Haley10.49%15.00%


Total206100.00%20100.00%



/*
 *      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;
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2337.10%228.57%


David S. Miller1930.65%114.29%


Linus Torvalds1422.58%114.29%


Arnaldo Carvalho de Melo34.84%114.29%


Eric Dumazet23.23%114.29%


Ian Morris11.61%114.29%


Total62100.00%7100.00%






int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
			       struct icmp6hdr *thdr, int len)
{
	struct sk_buff *skb;
	struct icmp6hdr *icmp6h;
	int err = 0;

	skb = skb_peek(&sk->sk_write_queue);
	if (!skb)
		goto out;

	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);
out:
	return err;
}


Contributors
PersonTokensPropCommitsCommitProp
Kazunori Miyazawa16474.89%110.00%


Linus Torvalds (pre-git)2210.05%220.00%


David S. Miller188.22%220.00%


Arnaldo Carvalho de Melo62.74%220.00%


Ian Morris52.28%220.00%


Al Viro41.83%110.00%


Total219100.00%10100.00%




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 = 0;

	csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
				      to, len, csum);
	skb->csum = csum_block_add(skb->csum, csum, odd);
	if (!(msg->type & ICMPV6_INFOMSG_MASK))
		nf_ct_attach(skb, org_skb);
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Kazunori Miyazawa7467.89%125.00%


Yasuyuki Kozakai1816.51%125.00%


David S. Miller1614.68%125.00%


Al Viro10.92%125.00%


Total109100.00%4100.00%



#if IS_ENABLED(CONFIG_IPV6_MIP6)



static void mip6_addr_swap(struct sk_buff *skb)
{
	struct ipv6hdr *iph = ipv6_hdr(skb);
	struct inet6_skb_parm *opt = IP6CB(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;
		}
	}
}

Contributors
PersonTokensPropCommitsCommitProp
Masahide Nakamura10291.89%125.00%


Arnaldo Carvalho de Melo65.41%250.00%


Alexey Dobriyan32.70%125.00%


Total111100.00%4100.00%



#else



static inline void mip6_addr_swap(struct sk_buff *skb) {}

Contributors
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Masahide Nakamura11100.00%1100.00%


Total11100.00%1100.00%



#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);
}


Contributors
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David S. Miller27695.17%337.50%


Martin KaFai Lau72.41%112.50%


Roopa Prabhu41.38%112.50%


Pravin B Shelar10.34%112.50%


Stephen Hemminger10.34%112.50%


Joe Perches10.34%112.50%


Total290100.00%8100.00%



/*
 *      Send an ICMP message in response to a packet in error
 */



static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
		       const struct in6_addr *force_saddr)
{
	struct net *net = dev_net(skb->dev);
	struct inet6_dev *idev = NULL;
	struct ipv6hdr *hdr = ipv6_hdr(skb);
	struct sock *sk;
	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 sockcm_cookie sockc_unused = {0};
	struct ipcm6_cookie ipc6;
	int iif = 0;
	int addr_type = 0;
	int len;
	int err = 0;
	u32 mark = IP6_REPLY_MARK(net, skb->mark);

	if ((u8 *)hdr < skb->head ||
	    (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
		return;

	/*
         *      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 = skb->dev->ifindex;
	else {
		dst = skb_dst(skb);
		iif = l3mdev_master_ifindex(dst ? dst->dev : 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 (!icmpv6_global_allow(type))
		goto out_bh_enable;

	mip6_addr_swap(skb);

	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;
	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);
	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));

	sk = icmpv6_xmit_lock(net);
	if (!sk)
		goto out_bh_enable;

	sk->sk_mark = mark;
	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;

	ipc6.tclass = np->tclass;
	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);
	ipc6.dontfrag = np->dontfrag;
	ipc6.opt = NULL;

	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);

	err = ip6_append_data(sk, icmpv6_getfrag, &msg,
			      len + sizeof(struct icmp6hdr),
			      sizeof(struct icmp6hdr),
			      &ipc6, &fl6, (struct rt6_info *)dst,
			      MSG_DONTWAIT, &sockc_unused);
	if (err) {
		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
		ip6_flush_pending_frames(sk);
	} else {
		err = 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();
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)23727.65%79.72%


Kazunori Miyazawa16018.67%11.39%


David S. Miller758.75%79.72%


Lorenzo Colitti414.78%34.17%


Björn Mork333.85%11.39%


Eric Dumazet323.73%56.94%


Hannes Frederic Sowa273.15%34.17%


David Ahern252.92%34.17%


Jesper Dangaard Brouer242.80%22.78%


Wei Wang222.57%11.39%


Hideaki Yoshifuji / 吉藤英明212.45%79.72%


Herbert Xu161.87%11.39%


Erich E. Hoover161.87%11.39%


François-Xavier Le Bail141.63%22.78%


Linus Torvalds121.40%34.17%


Arnaldo Carvalho de Melo111.28%34.17%


Benjamin Thery111.28%11.39%


Soheil Hassas Yeganeh101.17%11.39%


Denis V. Lunev101.17%34.17%


Randy Dunlap91.05%11.39%


Venkat Yekkirala70.82%11.39%


Simon Horman60.70%11.39%


Yasuyuki Kozakai60.70%11.39%


Alexey Dobriyan50.58%22.78%


Masahide Nakamura50.58%11.39%


Jan Oravec40.47%11.39%


Brian Haley30.35%22.78%


Joe Perches30.35%11.39%


Andi Kleen30.35%11.39%


Pravin B Shelar30.35%11.39%


Ville Nuorvala20.23%11.39%


Ian Morris20.23%22.78%


Daniel Lezcano20.23%11.39%


Total857100.00%72100.00%



/* 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);
	kfree_skb(skb);
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar2985.29%133.33%


Hideaki Yoshifuji / 吉藤英明38.82%133.33%


Eric Dumazet25.88%133.33%


Total34100.00%3100.00%



/* 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, 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);
	else
		icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
			   info, &temp_saddr);
	if (rt)
		ip6_rt_put(rt);

	kfree_skb(skb2);

	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
Eric Dumazet299100.00%3100.00%


Total299100.00%3100.00%




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;
	int err = 0;
	u32 mark = IP6_REPLY_MARK(net, skb->mark);
	struct sockcm_cookie sockc_unused = {0};

	saddr = &ipv6_hdr(skb)->daddr;

	if (!ipv6_unicast_destination(skb) &&
	    !(net->ipv6.sysctl.anycast_src_echo_reply &&
	      ipv6_anycast_destination(skb_dst(skb), saddr)))
		saddr =