Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 1940 insertions, 0 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
new file mode 100644
index 000000000..673a4a932
--- /dev/null
+++ b/net/ipv6/ndisc.c
@@ -0,0 +1,1940 @@
+/*
+ *	Neighbour Discovery for IPv6
+ *	Linux INET6 implementation
+ *
+ *	Authors:
+ *	Pedro Roque		<roque@di.fc.ul.pt>
+ *	Mike Shaver		<shaver@ingenia.com>
+ *
+ *	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:
+ *
+ *	Alexey I. Froloff		:	RFC6106 (DNSSL) support
+ *	Pierre Ynard			:	export userland ND options
+ *						through netlink (RDNSS support)
+ *	Lars Fenneberg			:	fixed MTU setting on receipt
+ *						of an RA.
+ *	Janos Farkas			:	kmalloc failure checks
+ *	Alexey Kuznetsov		:	state machine reworked
+ *						and moved to net/core.
+ *	Pekka Savola			:	RFC2461 validation
+ *	YOSHIFUJI Hideaki @USAGI	:	Verify ND options properly
+ */
+
+#define pr_fmt(fmt) "ICMPv6: " fmt
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/sched.h>
+#include <linux/net.h>
+#include <linux/in6.h>
+#include <linux/route.h>
+#include <linux/init.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+#ifdef CONFIG_SYSCTL
+#include <linux/sysctl.h>
+#endif
+
+#include <linux/if_addr.h>
+#include <linux/if_ether.h>
+#include <linux/if_arp.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+#include <linux/jhash.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/ndisc.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+#include <net/icmp.h>
+
+#include <net/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <net/flow.h>
+#include <net/ip6_checksum.h>
+#include <net/inet_common.h>
+#include <linux/proc_fs.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+
+static u32 ndisc_hash(const void *pkey,
+		      const struct net_device *dev,
+		      __u32 *hash_rnd);
+static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey);
+static int ndisc_constructor(struct neighbour *neigh);
+static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
+static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
+static int pndisc_constructor(struct pneigh_entry *n);
+static void pndisc_destructor(struct pneigh_entry *n);
+static void pndisc_redo(struct sk_buff *skb);
+
+static const struct neigh_ops ndisc_generic_ops = {
+	.family =		AF_INET6,
+	.solicit =		ndisc_solicit,
+	.error_report =		ndisc_error_report,
+	.output =		neigh_resolve_output,
+	.connected_output =	neigh_connected_output,
+};
+
+static const struct neigh_ops ndisc_hh_ops = {
+	.family =		AF_INET6,
+	.solicit =		ndisc_solicit,
+	.error_report =		ndisc_error_report,
+	.output =		neigh_resolve_output,
+	.connected_output =	neigh_resolve_output,
+};
+
+
+static const struct neigh_ops ndisc_direct_ops = {
+	.family =		AF_INET6,
+	.output =		neigh_direct_output,
+	.connected_output =	neigh_direct_output,
+};
+
+struct neigh_table nd_tbl = {
+	.family =	AF_INET6,
+	.key_len =	sizeof(struct in6_addr),
+	.protocol =	cpu_to_be16(ETH_P_IPV6),
+	.hash =		ndisc_hash,
+	.key_eq =	ndisc_key_eq,
+	.constructor =	ndisc_constructor,
+	.pconstructor =	pndisc_constructor,
+	.pdestructor =	pndisc_destructor,
+	.proxy_redo =	pndisc_redo,
+	.id =		"ndisc_cache",
+	.parms = {
+		.tbl			= &nd_tbl,
+		.reachable_time		= ND_REACHABLE_TIME,
+		.data = {
+			[NEIGH_VAR_MCAST_PROBES] = 3,
+			[NEIGH_VAR_UCAST_PROBES] = 3,
+			[NEIGH_VAR_RETRANS_TIME] = ND_RETRANS_TIMER,
+			[NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME,
+			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
+			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
+			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
+			[NEIGH_VAR_PROXY_QLEN] = 64,
+			[NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
+			[NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
+		},
+	},
+	.gc_interval =	  30 * HZ,
+	.gc_thresh1 =	 128,
+	.gc_thresh2 =	 512,
+	.gc_thresh3 =	1024,
+};
+EXPORT_SYMBOL_GPL(nd_tbl);
+
+void __ndisc_fill_addr_option(struct sk_buff *skb, int type, void *data,
+			      int data_len, int pad)
+{
+	int space = __ndisc_opt_addr_space(data_len, pad);
+	u8 *opt = skb_put(skb, space);
+
+	opt[0] = type;
+	opt[1] = space>>3;
+
+	memset(opt + 2, 0, pad);
+	opt   += pad;
+	space -= pad;
+
+	memcpy(opt+2, data, data_len);
+	data_len += 2;
+	opt += data_len;
+	space -= data_len;
+	if (space > 0)
+		memset(opt, 0, space);
+}
+EXPORT_SYMBOL_GPL(__ndisc_fill_addr_option);
+
+static inline void ndisc_fill_addr_option(struct sk_buff *skb, int type,
+					  void *data, u8 icmp6_type)
+{
+	__ndisc_fill_addr_option(skb, type, data, skb->dev->addr_len,
+				 ndisc_addr_option_pad(skb->dev->type));
+	ndisc_ops_fill_addr_option(skb->dev, skb, icmp6_type);
+}
+
+static inline void ndisc_fill_redirect_addr_option(struct sk_buff *skb,
+						   void *ha,
+						   const u8 *ops_data)
+{
+	ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, ha, NDISC_REDIRECT);
+	ndisc_ops_fill_redirect_addr_option(skb->dev, skb, ops_data);
+}
+
+static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur,
+					    struct nd_opt_hdr *end)
+{
+	int type;
+	if (!cur || !end || cur >= end)
+		return NULL;
+	type = cur->nd_opt_type;
+	do {
+		cur = ((void *)cur) + (cur->nd_opt_len << 3);
+	} while (cur < end && cur->nd_opt_type != type);
+	return cur <= end && cur->nd_opt_type == type ? cur : NULL;
+}
+
+static inline int ndisc_is_useropt(const struct net_device *dev,
+				   struct nd_opt_hdr *opt)
+{
+	return opt->nd_opt_type == ND_OPT_RDNSS ||
+		opt->nd_opt_type == ND_OPT_DNSSL ||
+		ndisc_ops_is_useropt(dev, opt->nd_opt_type);
+}
+
+static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev,
+					     struct nd_opt_hdr *cur,
+					     struct nd_opt_hdr *end)
+{
+	if (!cur || !end || cur >= end)
+		return NULL;
+	do {
+		cur = ((void *)cur) + (cur->nd_opt_len << 3);
+	} while (cur < end && !ndisc_is_useropt(dev, cur));
+	return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL;
+}
+
+struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
+					  u8 *opt, int opt_len,
+					  struct ndisc_options *ndopts)
+{
+	struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;
+
+	if (!nd_opt || opt_len < 0 || !ndopts)
+		return NULL;
+	memset(ndopts, 0, sizeof(*ndopts));
+	while (opt_len) {
+		int l;
+		if (opt_len < sizeof(struct nd_opt_hdr))
+			return NULL;
+		l = nd_opt->nd_opt_len << 3;
+		if (opt_len < l || l == 0)
+			return NULL;
+		if (ndisc_ops_parse_options(dev, nd_opt, ndopts))
+			goto next_opt;
+		switch (nd_opt->nd_opt_type) {
+		case ND_OPT_SOURCE_LL_ADDR:
+		case ND_OPT_TARGET_LL_ADDR:
+		case ND_OPT_MTU:
+		case ND_OPT_NONCE:
+		case ND_OPT_REDIRECT_HDR:
+			if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
+				ND_PRINTK(2, warn,
+					  "%s: duplicated ND6 option found: type=%d\n",
+					  __func__, nd_opt->nd_opt_type);
+			} else {
+				ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
+			}
+			break;
+		case ND_OPT_PREFIX_INFO:
+			ndopts->nd_opts_pi_end = nd_opt;
+			if (!ndopts->nd_opt_array[nd_opt->nd_opt_type])
+				ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
+			break;
+#ifdef CONFIG_IPV6_ROUTE_INFO
+		case ND_OPT_ROUTE_INFO:
+			ndopts->nd_opts_ri_end = nd_opt;
+			if (!ndopts->nd_opts_ri)
+				ndopts->nd_opts_ri = nd_opt;
+			break;
+#endif
+		default:
+			if (ndisc_is_useropt(dev, nd_opt)) {
+				ndopts->nd_useropts_end = nd_opt;
+				if (!ndopts->nd_useropts)
+					ndopts->nd_useropts = nd_opt;
+			} else {
+				/*
+				 * Unknown options must be silently ignored,
+				 * to accommodate future extension to the
+				 * protocol.
+				 */
+				ND_PRINTK(2, notice,
+					  "%s: ignored unsupported option; type=%d, len=%d\n",
+					  __func__,
+					  nd_opt->nd_opt_type,
+					  nd_opt->nd_opt_len);
+			}
+		}
+next_opt:
+		opt_len -= l;
+		nd_opt = ((void *)nd_opt) + l;
+	}
+	return ndopts;
+}
+
+int ndisc_mc_map(const struct in6_addr *addr, char *buf, struct net_device *dev, int dir)
+{
+	switch (dev->type) {
+	case ARPHRD_ETHER:
+	case ARPHRD_IEEE802:	/* Not sure. Check it later. --ANK */
+	case ARPHRD_FDDI:
+		ipv6_eth_mc_map(addr, buf);
+		return 0;
+	case ARPHRD_ARCNET:
+		ipv6_arcnet_mc_map(addr, buf);
+		return 0;
+	case ARPHRD_INFINIBAND:
+		ipv6_ib_mc_map(addr, dev->broadcast, buf);
+		return 0;
+	case ARPHRD_IPGRE:
+		return ipv6_ipgre_mc_map(addr, dev->broadcast, buf);
+	default:
+		if (dir) {
+			memcpy(buf, dev->broadcast, dev->addr_len);
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+EXPORT_SYMBOL(ndisc_mc_map);
+
+static u32 ndisc_hash(const void *pkey,
+		      const struct net_device *dev,
+		      __u32 *hash_rnd)
+{
+	return ndisc_hashfn(pkey, dev, hash_rnd);
+}
+
+static bool ndisc_key_eq(const struct neighbour *n, const void *pkey)
+{
+	return neigh_key_eq128(n, pkey);
+}
+
+static int ndisc_constructor(struct neighbour *neigh)
+{
+	struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key;
+	struct net_device *dev = neigh->dev;
+	struct inet6_dev *in6_dev;
+	struct neigh_parms *parms;
+	bool is_multicast = ipv6_addr_is_multicast(addr);
+
+	in6_dev = in6_dev_get(dev);
+	if (!in6_dev) {
+		return -EINVAL;
+	}
+
+	parms = in6_dev->nd_parms;
+	__neigh_parms_put(neigh->parms);
+	neigh->parms = neigh_parms_clone(parms);
+
+	neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST;
+	if (!dev->header_ops) {
+		neigh->nud_state = NUD_NOARP;
+		neigh->ops = &ndisc_direct_ops;
+		neigh->output = neigh_direct_output;
+	} else {
+		if (is_multicast) {
+			neigh->nud_state = NUD_NOARP;
+			ndisc_mc_map(addr, neigh->ha, dev, 1);
+		} else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
+			neigh->nud_state = NUD_NOARP;
+			memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
+			if (dev->flags&IFF_LOOPBACK)
+				neigh->type = RTN_LOCAL;
+		} else if (dev->flags&IFF_POINTOPOINT) {
+			neigh->nud_state = NUD_NOARP;
+			memcpy(neigh->ha, dev->broadcast, dev->addr_len);
+		}
+		if (dev->header_ops->cache)
+			neigh->ops = &ndisc_hh_ops;
+		else
+			neigh->ops = &ndisc_generic_ops;
+		if (neigh->nud_state&NUD_VALID)
+			neigh->output = neigh->ops->connected_output;
+		else
+			neigh->output = neigh->ops->output;
+	}
+	in6_dev_put(in6_dev);
+	return 0;
+}
+
+static int pndisc_constructor(struct pneigh_entry *n)
+{
+	struct in6_addr *addr = (struct in6_addr *)&n->key;
+	struct in6_addr maddr;
+	struct net_device *dev = n->dev;
+
+	if (!dev || !__in6_dev_get(dev))
+		return -EINVAL;
+	addrconf_addr_solict_mult(addr, &maddr);
+	ipv6_dev_mc_inc(dev, &maddr);
+	return 0;
+}
+
+static void pndisc_destructor(struct pneigh_entry *n)
+{
+	struct in6_addr *addr = (struct in6_addr *)&n->key;
+	struct in6_addr maddr;
+	struct net_device *dev = n->dev;
+
+	if (!dev || !__in6_dev_get(dev))
+		return;
+	addrconf_addr_solict_mult(addr, &maddr);
+	ipv6_dev_mc_dec(dev, &maddr);
+}
+
+static struct sk_buff *ndisc_alloc_skb(struct net_device *dev,
+				       int len)
+{
+	int hlen = LL_RESERVED_SPACE(dev);
+	int tlen = dev->needed_tailroom;
+	struct sock *sk = dev_net(dev)->ipv6.ndisc_sk;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC);
+	if (!skb) {
+		ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n",
+			  __func__);
+		return NULL;
+	}
+
+	skb->protocol = htons(ETH_P_IPV6);
+	skb->dev = dev;
+
+	skb_reserve(skb, hlen + sizeof(struct ipv6hdr));
+	skb_reset_transport_header(skb);
+
+	/* Manually assign socket ownership as we avoid calling
+	 * sock_alloc_send_pskb() to bypass wmem buffer limits
+	 */
+	skb_set_owner_w(skb, sk);
+
+	return skb;
+}
+
+static void ip6_nd_hdr(struct sk_buff *skb,
+		       const struct in6_addr *saddr,
+		       const struct in6_addr *daddr,
+		       int hop_limit, int len)
+{
+	struct ipv6hdr *hdr;
+	struct inet6_dev *idev;
+	unsigned tclass;
+
+	rcu_read_lock();
+	idev = __in6_dev_get(skb->dev);
+	tclass = idev ? idev->cnf.ndisc_tclass : 0;
+	rcu_read_unlock();
+
+	skb_push(skb, sizeof(*hdr));
+	skb_reset_network_header(skb);
+	hdr = ipv6_hdr(skb);
+
+	ip6_flow_hdr(hdr, tclass, 0);
+
+	hdr->payload_len = htons(len);
+	hdr->nexthdr = IPPROTO_ICMPV6;
+	hdr->hop_limit = hop_limit;
+
+	hdr->saddr = *saddr;
+	hdr->daddr = *daddr;
+}
+
+static void ndisc_send_skb(struct sk_buff *skb,
+			   const struct in6_addr *daddr,
+			   const struct in6_addr *saddr)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct net *net = dev_net(skb->dev);
+	struct sock *sk = net->ipv6.ndisc_sk;
+	struct inet6_dev *idev;
+	int err;
+	struct icmp6hdr *icmp6h = icmp6_hdr(skb);
+	u8 type;
+
+	type = icmp6h->icmp6_type;
+
+	if (!dst) {
+		struct flowi6 fl6;
+		int oif = skb->dev->ifindex;
+
+		icmpv6_flow_init(sk, &fl6, type, saddr, daddr, oif);
+		dst = icmp6_dst_alloc(skb->dev, &fl6);
+		if (IS_ERR(dst)) {
+			kfree_skb(skb);
+			return;
+		}
+
+		skb_dst_set(skb, dst);
+	}
+
+	icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, skb->len,
+					      IPPROTO_ICMPV6,
+					      csum_partial(icmp6h,
+							   skb->len, 0));
+
+	ip6_nd_hdr(skb, saddr, daddr, inet6_sk(sk)->hop_limit, skb->len);
+
+	rcu_read_lock();
+	idev = __in6_dev_get(dst->dev);
+	IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
+
+	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+		      net, sk, skb, NULL, dst->dev,
+		      dst_output);
+	if (!err) {
+		ICMP6MSGOUT_INC_STATS(net, idev, type);
+		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
+	}
+
+	rcu_read_unlock();
+}
+
+void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
+		   const struct in6_addr *solicited_addr,
+		   bool router, bool solicited, bool override, bool inc_opt)
+{
+	struct sk_buff *skb;
+	struct in6_addr tmpaddr;
+	struct inet6_ifaddr *ifp;
+	const struct in6_addr *src_addr;
+	struct nd_msg *msg;
+	int optlen = 0;
+
+	/* for anycast or proxy, solicited_addr != src_addr */
+	ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1);
+	if (ifp) {
+		src_addr = solicited_addr;
+		if (ifp->flags & IFA_F_OPTIMISTIC)
+			override = false;
+		inc_opt |= ifp->idev->cnf.force_tllao;
+		in6_ifa_put(ifp);
+	} else {
+		if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
+				       inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs,
+				       &tmpaddr))
+			return;
+		src_addr = &tmpaddr;
+	}
+
+	if (!dev->addr_len)
+		inc_opt = false;
+	if (inc_opt)
+		optlen += ndisc_opt_addr_space(dev,
+					       NDISC_NEIGHBOUR_ADVERTISEMENT);
+
+	skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
+	if (!skb)
+		return;
+
+	msg = skb_put(skb, sizeof(*msg));
+	*msg = (struct nd_msg) {
+		.icmph = {
+			.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,
+			.icmp6_router = router,
+			.icmp6_solicited = solicited,
+			.icmp6_override = override,
+		},
+		.target = *solicited_addr,
+	};
+
+	if (inc_opt)
+		ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
+				       dev->dev_addr,
+				       NDISC_NEIGHBOUR_ADVERTISEMENT);
+
+	ndisc_send_skb(skb, daddr, src_addr);
+}
+
+static void ndisc_send_unsol_na(struct net_device *dev)
+{
+	struct inet6_dev *idev;
+	struct inet6_ifaddr *ifa;
+
+	idev = in6_dev_get(dev);
+	if (!idev)
+		return;
+
+	read_lock_bh(&idev->lock);
+	list_for_each_entry(ifa, &idev->addr_list, if_list) {
+		/* skip tentative addresses until dad completes */
+		if (ifa->flags & IFA_F_TENTATIVE &&
+		    !(ifa->flags & IFA_F_OPTIMISTIC))
+			continue;
+
+		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr,
+			      /*router=*/ !!idev->cnf.forwarding,
+			      /*solicited=*/ false, /*override=*/ true,
+			      /*inc_opt=*/ true);
+	}
+	read_unlock_bh(&idev->lock);
+
+	in6_dev_put(idev);
+}
+
+void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
+		   const struct in6_addr *daddr, const struct in6_addr *saddr,
+		   u64 nonce)
+{
+	struct sk_buff *skb;
+	struct in6_addr addr_buf;
+	int inc_opt = dev->addr_len;
+	int optlen = 0;
+	struct nd_msg *msg;
+
+	if (!saddr) {
+		if (ipv6_get_lladdr(dev, &addr_buf,
+				   (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)))
+			return;
+		saddr = &addr_buf;
+	}
+
+	if (ipv6_addr_any(saddr))
+		inc_opt = false;
+	if (inc_opt)
+		optlen += ndisc_opt_addr_space(dev,
+					       NDISC_NEIGHBOUR_SOLICITATION);
+	if (nonce != 0)
+		optlen += 8;
+
+	skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
+	if (!skb)
+		return;
+
+	msg = skb_put(skb, sizeof(*msg));
+	*msg = (struct nd_msg) {
+		.icmph = {
+			.icmp6_type = NDISC_NEIGHBOUR_SOLICITATION,
+		},
+		.target = *solicit,
+	};
+
+	if (inc_opt)
+		ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
+				       dev->dev_addr,
+				       NDISC_NEIGHBOUR_SOLICITATION);
+	if (nonce != 0) {
+		u8 *opt = skb_put(skb, 8);
+
+		opt[0] = ND_OPT_NONCE;
+		opt[1] = 8 >> 3;
+		memcpy(opt + 2, &nonce, 6);
+	}
+
+	ndisc_send_skb(skb, daddr, saddr);
+}
+
+void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr,
+		   const struct in6_addr *daddr)
+{
+	struct sk_buff *skb;
+	struct rs_msg *msg;
+	int send_sllao = dev->addr_len;
+	int optlen = 0;
+
+#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
+	/*
+	 * According to section 2.2 of RFC 4429, we must not
+	 * send router solicitations with a sllao from
+	 * optimistic addresses, but we may send the solicitation
+	 * if we don't include the sllao.  So here we check
+	 * if our address is optimistic, and if so, we
+	 * suppress the inclusion of the sllao.
+	 */
+	if (send_sllao) {
+		struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr,
+							   dev, 1);
+		if (ifp) {
+			if (ifp->flags & IFA_F_OPTIMISTIC)  {
+				send_sllao = 0;
+			}
+			in6_ifa_put(ifp);
+		} else {
+			send_sllao = 0;
+		}
+	}
+#endif
+	if (send_sllao)
+		optlen += ndisc_opt_addr_space(dev, NDISC_ROUTER_SOLICITATION);
+
+	skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
+	if (!skb)
+		return;
+
+	msg = skb_put(skb, sizeof(*msg));
+	*msg = (struct rs_msg) {
+		.icmph = {
+			.icmp6_type = NDISC_ROUTER_SOLICITATION,
+		},
+	};
+
+	if (send_sllao)
+		ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
+				       dev->dev_addr,
+				       NDISC_ROUTER_SOLICITATION);
+
+	ndisc_send_skb(skb, daddr, saddr);
+}
+
+
+static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb)
+{
+	/*
+	 *	"The sender MUST return an ICMP
+	 *	 destination unreachable"
+	 */
+	dst_link_failure(skb);
+	kfree_skb(skb);
+}
+
+/* Called with locked neigh: either read or both */
+
+static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
+{
+	struct in6_addr *saddr = NULL;
+	struct in6_addr mcaddr;
+	struct net_device *dev = neigh->dev;
+	struct in6_addr *target = (struct in6_addr *)&neigh->primary_key;
+	int probes = atomic_read(&neigh->probes);
+
+	if (skb && ipv6_chk_addr_and_flags(dev_net(dev), &ipv6_hdr(skb)->saddr,
+					   dev, false, 1,
+					   IFA_F_TENTATIVE|IFA_F_OPTIMISTIC))
+		saddr = &ipv6_hdr(skb)->saddr;
+	probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
+	if (probes < 0) {
+		if (!(neigh->nud_state & NUD_VALID)) {
+			ND_PRINTK(1, dbg,
+				  "%s: trying to ucast probe in NUD_INVALID: %pI6\n",
+				  __func__, target);
+		}
+		ndisc_send_ns(dev, target, target, saddr, 0);
+	} else if ((probes -= NEIGH_VAR(neigh->parms, APP_PROBES)) < 0) {
+		neigh_app_ns(neigh);
+	} else {
+		addrconf_addr_solict_mult(target, &mcaddr);
+		ndisc_send_ns(dev, target, &mcaddr, saddr, 0);
+	}
+}
+
+static int pndisc_is_router(const void *pkey,
+			    struct net_device *dev)
+{
+	struct pneigh_entry *n;
+	int ret = -1;
+
+	read_lock_bh(&nd_tbl.lock);
+	n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev);
+	if (n)
+		ret = !!(n->flags & NTF_ROUTER);
+	read_unlock_bh(&nd_tbl.lock);
+
+	return ret;
+}
+
+void ndisc_update(const struct net_device *dev, struct neighbour *neigh,
+		  const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type,
+		  struct ndisc_options *ndopts)
+{
+	neigh_update(neigh, lladdr, new, flags, 0);
+	/* report ndisc ops about neighbour update */
+	ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts);
+}
+
+static void ndisc_recv_ns(struct sk_buff *skb)
+{
+	struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
+	const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
+	const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
+	u8 *lladdr = NULL;
+	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
+				    offsetof(struct nd_msg, opt));
+	struct ndisc_options ndopts;
+	struct net_device *dev = skb->dev;
+	struct inet6_ifaddr *ifp;
+	struct inet6_dev *idev = NULL;
+	struct neighbour *neigh;
+	int dad = ipv6_addr_any(saddr);
+	bool inc;
+	int is_router = -1;
+	u64 nonce = 0;
+
+	if (skb->len < sizeof(struct nd_msg)) {
+		ND_PRINTK(2, warn, "NS: packet too short\n");
+		return;
+	}
+
+	if (ipv6_addr_is_multicast(&msg->target)) {
+		ND_PRINTK(2, warn, "NS: multicast target address\n");
+		return;
+	}
+
+	/*
+	 * RFC2461 7.1.1:
+	 * DAD has to be destined for solicited node multicast address.
+	 */
+	if (dad && !ipv6_addr_is_solict_mult(daddr)) {
+		ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n");
+		return;
+	}
+
+	if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
+		ND_PRINTK(2, warn, "NS: invalid ND options\n");
+		return;
+	}
+
+	if (ndopts.nd_opts_src_lladdr) {
+		lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
+		if (!lladdr) {
+			ND_PRINTK(2, warn,
+				  "NS: invalid link-layer address length\n");
+			return;
+		}
+
+		/* RFC2461 7.1.1:
+		 *	If the IP source address is the unspecified address,
+		 *	there MUST NOT be source link-layer address option
+		 *	in the message.
+		 */
+		if (dad) {
+			ND_PRINTK(2, warn,
+				  "NS: bad DAD packet (link-layer address option)\n");
+			return;
+		}
+	}
+	if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1)
+		memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6);
+
+	inc = ipv6_addr_is_multicast(daddr);
+
+	ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
+	if (ifp) {
+have_ifp:
+		if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
+			if (dad) {
+				if (nonce != 0 && ifp->dad_nonce == nonce) {
+					u8 *np = (u8 *)&nonce;
+					/* Matching nonce if looped back */
+					ND_PRINTK(2, notice,
+						  "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n",
+						  ifp->idev->dev->name,
+						  &ifp->addr, np);
+					goto out;
+				}
+				/*
+				 * We are colliding with another node
+				 * who is doing DAD
+				 * so fail our DAD process
+				 */
+				addrconf_dad_failure(skb, ifp);
+				return;
+			} else {
+				/*
+				 * This is not a dad solicitation.
+				 * If we are an optimistic node,
+				 * we should respond.
+				 * Otherwise, we should ignore it.
+				 */
+				if (!(ifp->flags & IFA_F_OPTIMISTIC))
+					goto out;
+			}
+		}
+
+		idev = ifp->idev;
+	} else {
+		struct net *net = dev_net(dev);
+
+		/* perhaps an address on the master device */
+		if (netif_is_l3_slave(dev)) {
+			struct net_device *mdev;
+
+			mdev = netdev_master_upper_dev_get_rcu(dev);
+			if (mdev) {
+				ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1);
+				if (ifp)
+					goto have_ifp;
+			}
+		}
+
+		idev = in6_dev_get(dev);
+		if (!idev) {
+			/* XXX: count this drop? */
+			return;
+		}
+
+		if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
+		    (idev->cnf.forwarding &&
+		     (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
+		     (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
+			if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
+			    skb->pkt_type != PACKET_HOST &&
+			    inc &&
+			    NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) {
+				/*
+				 * for anycast or proxy,
+				 * sender should delay its response
+				 * by a random time between 0 and
+				 * MAX_ANYCAST_DELAY_TIME seconds.
+				 * (RFC2461) -- yoshfuji
+				 */
+				struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
+				if (n)
+					pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
+				goto out;
+			}
+		} else
+			goto out;
+	}
+
+	if (is_router < 0)
+		is_router = idev->cnf.forwarding;
+
+	if (dad) {
+		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target,
+			      !!is_router, false, (ifp != NULL), true);
+		goto out;
+	}
+
+	if (inc)
+		NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast);
+	else
+		NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast);
+
+	/*
+	 *	update / create cache entry
+	 *	for the source address
+	 */
+	neigh = __neigh_lookup(&nd_tbl, saddr, dev,
+			       !inc || lladdr || !dev->addr_len);
+	if (neigh)
+		ndisc_update(dev, neigh, lladdr, NUD_STALE,
+			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
+			     NEIGH_UPDATE_F_OVERRIDE,
+			     NDISC_NEIGHBOUR_SOLICITATION, &ndopts);
+	if (neigh || !dev->header_ops) {
+		ndisc_send_na(dev, saddr, &msg->target, !!is_router,
+			      true, (ifp != NULL && inc), inc);
+		if (neigh)
+			neigh_release(neigh);
+	}
+
+out:
+	if (ifp)
+		in6_ifa_put(ifp);
+	else
+		in6_dev_put(idev);
+}
+
+static void ndisc_recv_na(struct sk_buff *skb)
+{
+	struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
+	struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
+	const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
+	u8 *lladdr = NULL;
+	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
+				    offsetof(struct nd_msg, opt));
+	struct ndisc_options ndopts;
+	struct net_device *dev = skb->dev;
+	struct inet6_dev *idev = __in6_dev_get(dev);
+	struct inet6_ifaddr *ifp;
+	struct neighbour *neigh;
+
+	if (skb->len < sizeof(struct nd_msg)) {
+		ND_PRINTK(2, warn, "NA: packet too short\n");
+		return;
+	}
+
+	if (ipv6_addr_is_multicast(&msg->target)) {
+		ND_PRINTK(2, warn, "NA: target address is multicast\n");
+		return;
+	}
+
+	if (ipv6_addr_is_multicast(daddr) &&
+	    msg->icmph.icmp6_solicited) {
+		ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n");
+		return;
+	}
+
+	/* For some 802.11 wireless deployments (and possibly other networks),
+	 * there will be a NA proxy and unsolicitd packets are attacks
+	 * and thus should not be accepted.
+	 */
+	if (!msg->icmph.icmp6_solicited && idev &&
+	    idev->cnf.drop_unsolicited_na)
+		return;
+
+	if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
+		ND_PRINTK(2, warn, "NS: invalid ND option\n");
+		return;
+	}
+	if (ndopts.nd_opts_tgt_lladdr) {
+		lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
+		if (!lladdr) {
+			ND_PRINTK(2, warn,
+				  "NA: invalid link-layer address length\n");
+			return;
+		}
+	}
+	ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
+	if (ifp) {
+		if (skb->pkt_type != PACKET_LOOPBACK
+		    && (ifp->flags & IFA_F_TENTATIVE)) {
+				addrconf_dad_failure(skb, ifp);
+				return;
+		}
+		/* What should we make now? The advertisement
+		   is invalid, but ndisc specs say nothing
+		   about it. It could be misconfiguration, or
+		   an smart proxy agent tries to help us :-)
+
+		   We should not print the error if NA has been
+		   received from loopback - it is just our own
+		   unsolicited advertisement.
+		 */
+		if (skb->pkt_type != PACKET_LOOPBACK)
+			ND_PRINTK(1, warn,
+				  "NA: %pM advertised our address %pI6c on %s!\n",
+				  eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name);
+		in6_ifa_put(ifp);
+		return;
+	}
+	neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
+
+	if (neigh) {
+		u8 old_flags = neigh->flags;
+		struct net *net = dev_net(dev);
+
+		if (neigh->nud_state & NUD_FAILED)
+			goto out;
+
+		/*
+		 * Don't update the neighbor cache entry on a proxy NA from
+		 * ourselves because either the proxied node is off link or it
+		 * has already sent a NA to us.
+		 */
+		if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
+		    net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
+		    pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
+			/* XXX: idev->cnf.proxy_ndp */
+			goto out;
+		}
+
+		ndisc_update(dev, neigh, lladdr,
+			     msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE,
+			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
+			     (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
+			     NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
+			     (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0),
+			     NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts);
+
+		if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
+			/*
+			 * Change: router to host
+			 */
+			rt6_clean_tohost(dev_net(dev),  saddr);
+		}
+
+out:
+		neigh_release(neigh);
+	}
+}
+
+static void ndisc_recv_rs(struct sk_buff *skb)
+{
+	struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb);
+	unsigned long ndoptlen = skb->len - sizeof(*rs_msg);
+	struct neighbour *neigh;
+	struct inet6_dev *idev;
+	const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
+	struct ndisc_options ndopts;
+	u8 *lladdr = NULL;
+
+	if (skb->len < sizeof(*rs_msg))
+		return;
+
+	idev = __in6_dev_get(skb->dev);
+	if (!idev) {
+		ND_PRINTK(1, err, "RS: can't find in6 device\n");
+		return;
+	}
+
+	/* Don't accept RS if we're not in router mode */
+	if (!idev->cnf.forwarding)
+		goto out;
+
+	/*
+	 * Don't update NCE if src = ::;
+	 * this implies that the source node has no ip address assigned yet.
+	 */
+	if (ipv6_addr_any(saddr))
+		goto out;
+
+	/* Parse ND options */
+	if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts)) {
+		ND_PRINTK(2, notice, "NS: invalid ND option, ignored\n");
+		goto out;
+	}
+
+	if (ndopts.nd_opts_src_lladdr) {
+		lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
+					     skb->dev);
+		if (!lladdr)
+			goto out;
+	}
+
+	neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
+	if (neigh) {
+		ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
+			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
+			     NEIGH_UPDATE_F_OVERRIDE|
+			     NEIGH_UPDATE_F_OVERRIDE_ISROUTER,
+			     NDISC_ROUTER_SOLICITATION, &ndopts);
+		neigh_release(neigh);
+	}
+out:
+	return;
+}
+
+static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
+{
+	struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	struct nduseroptmsg *ndmsg;
+	struct net *net = dev_net(ra->dev);
+	int err;
+	int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
+				    + (opt->nd_opt_len << 3));
+	size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));
+
+	skb = nlmsg_new(msg_size, GFP_ATOMIC);
+	if (!skb) {
+		err = -ENOBUFS;
+		goto errout;
+	}
+
+	nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
+	if (!nlh) {
+		goto nla_put_failure;
+	}
+
+	ndmsg = nlmsg_data(nlh);
+	ndmsg->nduseropt_family = AF_INET6;
+	ndmsg->nduseropt_ifindex = ra->dev->ifindex;
+	ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
+	ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
+	ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;
+
+	memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);
+
+	if (nla_put_in6_addr(skb, NDUSEROPT_SRCADDR, &ipv6_hdr(ra)->saddr))
+		goto nla_put_failure;
+	nlmsg_end(skb, nlh);
+
+	rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC);
+	return;
+
+nla_put_failure:
+	nlmsg_free(skb);
+	err = -EMSGSIZE;
+errout:
+	rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
+}
+
+static void ndisc_router_discovery(struct sk_buff *skb)
+{
+	struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
+	struct neighbour *neigh = NULL;
+	struct inet6_dev *in6_dev;
+	struct fib6_info *rt = NULL;
+	struct net *net;
+	int lifetime;
+	struct ndisc_options ndopts;
+	int optlen;
+	unsigned int pref = 0;
+	__u32 old_if_flags;
+	bool send_ifinfo_notify = false;
+
+	__u8 *opt = (__u8 *)(ra_msg + 1);
+
+	optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) -
+		sizeof(struct ra_msg);
+
+	ND_PRINTK(2, info,
+		  "RA: %s, dev: %s\n",
+		  __func__, skb->dev->name);
+	if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
+		ND_PRINTK(2, warn, "RA: source address is not link-local\n");
+		return;
+	}
+	if (optlen < 0) {
+		ND_PRINTK(2, warn, "RA: packet too short\n");
+		return;
+	}
+
+#ifdef CONFIG_IPV6_NDISC_NODETYPE
+	if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
+		ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
+		return;
+	}
+#endif
+
+	/*
+	 *	set the RA_RECV flag in the interface
+	 */
+
+	in6_dev = __in6_dev_get(skb->dev);
+	if (!in6_dev) {
+		ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
+			  skb->dev->name);
+		return;
+	}
+
+	if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) {
+		ND_PRINTK(2, warn, "RA: invalid ND options\n");
+		return;
+	}
+
+	if (!ipv6_accept_ra(in6_dev)) {
+		ND_PRINTK(2, info,
+			  "RA: %s, did not accept ra for dev: %s\n",
+			  __func__, skb->dev->name);
+		goto skip_linkparms;
+	}
+
+#ifdef CONFIG_IPV6_NDISC_NODETYPE
+	/* skip link-specific parameters from interior routers */
+	if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
+		ND_PRINTK(2, info,
+			  "RA: %s, nodetype is NODEFAULT, dev: %s\n",
+			  __func__, skb->dev->name);
+		goto skip_linkparms;
+	}
+#endif
+
+	if (in6_dev->if_flags & IF_RS_SENT) {
+		/*
+		 *	flag that an RA was received after an RS was sent
+		 *	out on this interface.
+		 */
+		in6_dev->if_flags |= IF_RA_RCVD;
+	}
+
+	/*
+	 * Remember the managed/otherconf flags from most recently
+	 * received RA message (RFC 2462) -- yoshfuji
+	 */
+	old_if_flags = in6_dev->if_flags;
+	in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
+				IF_RA_OTHERCONF)) |
+				(ra_msg->icmph.icmp6_addrconf_managed ?
+					IF_RA_MANAGED : 0) |
+				(ra_msg->icmph.icmp6_addrconf_other ?
+					IF_RA_OTHERCONF : 0);
+
+	if (old_if_flags != in6_dev->if_flags)
+		send_ifinfo_notify = true;
+
+	if (!in6_dev->cnf.accept_ra_defrtr) {
+		ND_PRINTK(2, info,
+			  "RA: %s, defrtr is false for dev: %s\n",
+			  __func__, skb->dev->name);
+		goto skip_defrtr;
+	}
+
+	/* Do not accept RA with source-addr found on local machine unless
+	 * accept_ra_from_local is set to true.
+	 */
+	net = dev_net(in6_dev->dev);
+	if (!in6_dev->cnf.accept_ra_from_local &&
+	    ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
+		ND_PRINTK(2, info,
+			  "RA from local address detected on dev: %s: default router ignored\n",
+			  skb->dev->name);
+		goto skip_defrtr;
+	}
+
+	lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
+
+#ifdef CONFIG_IPV6_ROUTER_PREF
+	pref = ra_msg->icmph.icmp6_router_pref;
+	/* 10b is handled as if it were 00b (medium) */
+	if (pref == ICMPV6_ROUTER_PREF_INVALID ||
+	    !in6_dev->cnf.accept_ra_rtr_pref)
+		pref = ICMPV6_ROUTER_PREF_MEDIUM;
+#endif
+
+	rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev);
+
+	if (rt) {
+		neigh = ip6_neigh_lookup(&rt->fib6_nh.nh_gw,
+					 rt->fib6_nh.nh_dev, NULL,
+					  &ipv6_hdr(skb)->saddr);
+		if (!neigh) {
+			ND_PRINTK(0, err,
+				  "RA: %s got default router without neighbour\n",
+				  __func__);
+			fib6_info_release(rt);
+			return;
+		}
+	}
+	if (rt && lifetime == 0) {
+		ip6_del_rt(net, rt);
+		rt = NULL;
+	}
+
+	ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, for dev: %s\n",
+		  rt, lifetime, skb->dev->name);
+	if (!rt && lifetime) {
+		ND_PRINTK(3, info, "RA: adding default router\n");
+
+		rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
+					 skb->dev, pref);
+		if (!rt) {
+			ND_PRINTK(0, err,
+				  "RA: %s failed to add default route\n",
+				  __func__);
+			return;
+		}
+
+		neigh = ip6_neigh_lookup(&rt->fib6_nh.nh_gw,
+					 rt->fib6_nh.nh_dev, NULL,
+					  &ipv6_hdr(skb)->saddr);
+		if (!neigh) {
+			ND_PRINTK(0, err,
+				  "RA: %s got default router without neighbour\n",
+				  __func__);
+			fib6_info_release(rt);
+			return;
+		}
+		neigh->flags |= NTF_ROUTER;
+	} else if (rt) {
+		rt->fib6_flags = (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
+	}
+
+	if (rt)
+		fib6_set_expires(rt, jiffies + (HZ * lifetime));
+	if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&
+	    ra_msg->icmph.icmp6_hop_limit) {
+		if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {
+			in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
+			fib6_metric_set(rt, RTAX_HOPLIMIT,
+					ra_msg->icmph.icmp6_hop_limit);
+		} else {
+			ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n");
+		}
+	}
+
+skip_defrtr:
+
+	/*
+	 *	Update Reachable Time and Retrans Timer
+	 */
+
+	if (in6_dev->nd_parms) {
+		unsigned long rtime = ntohl(ra_msg->retrans_timer);
+
+		if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
+			rtime = (rtime*HZ)/1000;
+			if (rtime < HZ/10)
+				rtime = HZ/10;
+			NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime);
+			in6_dev->tstamp = jiffies;
+			send_ifinfo_notify = true;
+		}
+
+		rtime = ntohl(ra_msg->reachable_time);
+		if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
+			rtime = (rtime*HZ)/1000;
+
+			if (rtime < HZ/10)
+				rtime = HZ/10;
+
+			if (rtime != NEIGH_VAR(in6_dev->nd_parms, BASE_REACHABLE_TIME)) {
+				NEIGH_VAR_SET(in6_dev->nd_parms,
+					      BASE_REACHABLE_TIME, rtime);
+				NEIGH_VAR_SET(in6_dev->nd_parms,
+					      GC_STALETIME, 3 * rtime);
+				in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
+				in6_dev->tstamp = jiffies;
+				send_ifinfo_notify = true;
+			}
+		}
+	}
+
+	/*
+	 *	Send a notify if RA changed managed/otherconf flags or timer settings
+	 */
+	if (send_ifinfo_notify)
+		inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
+
+skip_linkparms:
+
+	/*
+	 *	Process options.
+	 */
+
+	if (!neigh)
+		neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr,
+				       skb->dev, 1);
+	if (neigh) {
+		u8 *lladdr = NULL;
+		if (ndopts.nd_opts_src_lladdr) {
+			lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
+						     skb->dev);
+			if (!lladdr) {
+				ND_PRINTK(2, warn,
+					  "RA: invalid link-layer address length\n");
+				goto out;
+			}
+		}
+		ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
+			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
+			     NEIGH_UPDATE_F_OVERRIDE|
+			     NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
+			     NEIGH_UPDATE_F_ISROUTER,
+			     NDISC_ROUTER_ADVERTISEMENT, &ndopts);
+	}
+
+	if (!ipv6_accept_ra(in6_dev)) {
+		ND_PRINTK(2, info,
+			  "RA: %s, accept_ra is false for dev: %s\n",
+			  __func__, skb->dev->name);
+		goto out;
+	}
+
+#ifdef CONFIG_IPV6_ROUTE_INFO
+	if (!in6_dev->cnf.accept_ra_from_local &&
+	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+			  in6_dev->dev, 0)) {
+		ND_PRINTK(2, info,
+			  "RA from local address detected on dev: %s: router info ignored.\n",
+			  skb->dev->name);
+		goto skip_routeinfo;
+	}
+
+	if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
+		struct nd_opt_hdr *p;
+		for (p = ndopts.nd_opts_ri;
+		     p;
+		     p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
+			struct route_info *ri = (struct route_info *)p;
+#ifdef CONFIG_IPV6_NDISC_NODETYPE
+			if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
+			    ri->prefix_len == 0)
+				continue;
+#endif
+			if (ri->prefix_len == 0 &&
+			    !in6_dev->cnf.accept_ra_defrtr)
+				continue;
+			if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
+				continue;
+			if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
+				continue;
+			rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
+				      &ipv6_hdr(skb)->saddr);
+		}
+	}
+
+skip_routeinfo:
+#endif
+
+#ifdef CONFIG_IPV6_NDISC_NODETYPE
+	/* skip link-specific ndopts from interior routers */
+	if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
+		ND_PRINTK(2, info,
+			  "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n",
+			  __func__, skb->dev->name);
+		goto out;
+	}
+#endif
+
+	if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
+		struct nd_opt_hdr *p;
+		for (p = ndopts.nd_opts_pi;
+		     p;
+		     p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
+			addrconf_prefix_rcv(skb->dev, (u8 *)p,
+					    (p->nd_opt_len) << 3,
+					    ndopts.nd_opts_src_lladdr != NULL);
+		}
+	}
+
+	if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
+		__be32 n;
+		u32 mtu;
+
+		memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
+		mtu = ntohl(n);
+
+		if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
+			ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
+		} else if (in6_dev->cnf.mtu6 != mtu) {
+			in6_dev->cnf.mtu6 = mtu;
+			fib6_metric_set(rt, RTAX_MTU, mtu);
+			rt6_mtu_change(skb->dev, mtu);
+		}
+	}
+
+	if (ndopts.nd_useropts) {
+		struct nd_opt_hdr *p;
+		for (p = ndopts.nd_useropts;
+		     p;
+		     p = ndisc_next_useropt(skb->dev, p,
+					    ndopts.nd_useropts_end)) {
+			ndisc_ra_useropt(skb, p);
+		}
+	}
+
+	if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
+		ND_PRINTK(2, warn, "RA: invalid RA options\n");
+	}
+out:
+	fib6_info_release(rt);
+	if (neigh)
+		neigh_release(neigh);
+}
+
+static void ndisc_redirect_rcv(struct sk_buff *skb)
+{
+	u8 *hdr;
+	struct ndisc_options ndopts;
+	struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
+	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
+				    offsetof(struct rd_msg, opt));
+
+#ifdef CONFIG_IPV6_NDISC_NODETYPE
+	switch (skb->ndisc_nodetype) {
+	case NDISC_NODETYPE_HOST:
+	case NDISC_NODETYPE_NODEFAULT:
+		ND_PRINTK(2, warn,
+			  "Redirect: from host or unauthorized router\n");
+		return;
+	}
+#endif
+
+	if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
+		ND_PRINTK(2, warn,
+			  "Redirect: source address is not link-local\n");
+		return;
+	}
+
+	if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
+		return;
+
+	if (!ndopts.nd_opts_rh) {
+		ip6_redirect_no_header(skb, dev_net(skb->dev),
+					skb->dev->ifindex, 0);
+		return;
+	}
+
+	hdr = (u8 *)ndopts.nd_opts_rh;
+	hdr += 8;
+	if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
+		return;
+
+	icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
+}
+
+static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
+					   struct sk_buff *orig_skb,
+					   int rd_len)
+{
+	u8 *opt = skb_put(skb, rd_len);
+
+	memset(opt, 0, 8);
+	*(opt++) = ND_OPT_REDIRECT_HDR;
+	*(opt++) = (rd_len >> 3);
+	opt += 6;
+
+	skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt,
+		      rd_len - 8);
+}
+
+void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
+{
+	struct net_device *dev = skb->dev;
+	struct net *net = dev_net(dev);
+	struct sock *sk = net->ipv6.ndisc_sk;
+	int optlen = 0;
+	struct inet_peer *peer;
+	struct sk_buff *buff;
+	struct rd_msg *msg;
+	struct in6_addr saddr_buf;
+	struct rt6_info *rt;
+	struct dst_entry *dst;
+	struct flowi6 fl6;
+	int rd_len;
+	u8 ha_buf[MAX_ADDR_LEN], *ha = NULL,
+	   ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
+	bool ret;
+
+	if (netif_is_l3_master(skb->dev)) {
+		dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
+		if (!dev)
+			return;
+	}
+
+	if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
+		ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
+			  dev->name);
+		return;
+	}
+
+	if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
+	    ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
+		ND_PRINTK(2, warn,
+			  "Redirect: target address is not link-local unicast\n");
+		return;
+	}
+
+	icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT,
+			 &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);
+
+	dst = ip6_route_output(net, NULL, &fl6);
+	if (dst->error) {
+		dst_release(dst);
+		return;
+	}
+	dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
+	if (IS_ERR(dst))
+		return;
+
+	rt = (struct rt6_info *) dst;
+
+	if (rt->rt6i_flags & RTF_GATEWAY) {
+		ND_PRINTK(2, warn,
+			  "Redirect: destination is not a neighbour\n");
+		goto release;
+	}
+	peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1);
+	ret = inet_peer_xrlim_allow(peer, 1*HZ);
+	if (peer)
+		inet_putpeer(peer);
+	if (!ret)
+		goto release;
+
+	if (dev->addr_len) {
+		struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target);
+		if (!neigh) {
+			ND_PRINTK(2, warn,
+				  "Redirect: no neigh for target address\n");
+			goto release;
+		}
+
+		read_lock_bh(&neigh->lock);
+		if (neigh->nud_state & NUD_VALID) {
+			memcpy(ha_buf, neigh->ha, dev->addr_len);
+			read_unlock_bh(&neigh->lock);
+			ha = ha_buf;
+			optlen += ndisc_redirect_opt_addr_space(dev, neigh,
+								ops_data_buf,
+								&ops_data);
+		} else
+			read_unlock_bh(&neigh->lock);
+
+		neigh_release(neigh);
+	}
+
+	rd_len = min_t(unsigned int,
+		       IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
+		       skb->len + 8);
+	rd_len &= ~0x7;
+	optlen += rd_len;
+
+	buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
+	if (!buff)
+		goto release;
+
+	msg = skb_put(buff, sizeof(*msg));
+	*msg = (struct rd_msg) {
+		.icmph = {
+			.icmp6_type = NDISC_REDIRECT,
+		},
+		.target = *target,
+		.dest = ipv6_hdr(skb)->daddr,
+	};
+
+	/*
+	 *	include target_address option
+	 */
+
+	if (ha)
+		ndisc_fill_redirect_addr_option(buff, ha, ops_data);
+
+	/*
+	 *	build redirect option and copy skb over to the new packet.
+	 */
+
+	if (rd_len)
+		ndisc_fill_redirect_hdr_option(buff, skb, rd_len);
+
+	skb_dst_set(buff, dst);
+	ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf);
+	return;
+
+release:
+	dst_release(dst);
+}
+
+static void pndisc_redo(struct sk_buff *skb)
+{
+	ndisc_recv_ns(skb);
+	kfree_skb(skb);
+}
+
+static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
+{
+	struct inet6_dev *idev = __in6_dev_get(skb->dev);
+
+	if (!idev)
+		return true;
+	if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
+	    idev->cnf.suppress_frag_ndisc) {
+		net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
+		return true;
+	}
+	return false;
+}
+
+int ndisc_rcv(struct sk_buff *skb)
+{
+	struct nd_msg *msg;
+
+	if (ndisc_suppress_frag_ndisc(skb))
+		return 0;
+
+	if (skb_linearize(skb))
+		return 0;
+
+	msg = (struct nd_msg *)skb_transport_header(skb);
+
+	__skb_push(skb, skb->data - skb_transport_header(skb));
+
+	if (ipv6_hdr(skb)->hop_limit != 255) {
+		ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n",
+			  ipv6_hdr(skb)->hop_limit);
+		return 0;
+	}
+
+	if (msg->icmph.icmp6_code != 0) {
+		ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
+			  msg->icmph.icmp6_code);
+		return 0;
+	}
+
+	switch (msg->icmph.icmp6_type) {
+	case NDISC_NEIGHBOUR_SOLICITATION:
+		memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
+		ndisc_recv_ns(skb);
+		break;
+
+	case NDISC_NEIGHBOUR_ADVERTISEMENT:
+		ndisc_recv_na(skb);
+		break;
+
+	case NDISC_ROUTER_SOLICITATION:
+		ndisc_recv_rs(skb);
+		break;
+
+	case NDISC_ROUTER_ADVERTISEMENT:
+		ndisc_router_discovery(skb);
+		break;
+
+	case NDISC_REDIRECT:
+		ndisc_redirect_rcv(skb);
+		break;
+	}
+
+	return 0;
+}
+
+static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct netdev_notifier_change_info *change_info;
+	struct net *net = dev_net(dev);
+	struct inet6_dev *idev;
+
+	switch (event) {
+	case NETDEV_CHANGEADDR:
+		neigh_changeaddr(&nd_tbl, dev);
+		fib6_run_gc(0, net, false);
+		/* fallthrough */
+	case NETDEV_UP:
+		idev = in6_dev_get(dev);
+		if (!idev)
+			break;
+		if (idev->cnf.ndisc_notify ||
+		    net->ipv6.devconf_all->ndisc_notify)
+			ndisc_send_unsol_na(dev);
+		in6_dev_put(idev);
+		break;
+	case NETDEV_CHANGE:
+		change_info = ptr;
+		if (change_info->flags_changed & IFF_NOARP)
+			neigh_changeaddr(&nd_tbl, dev);
+		break;
+	case NETDEV_DOWN:
+		neigh_ifdown(&nd_tbl, dev);
+		fib6_run_gc(0, net, false);
+		break;
+	case NETDEV_NOTIFY_PEERS:
+		ndisc_send_unsol_na(dev);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ndisc_netdev_notifier = {
+	.notifier_call = ndisc_netdev_event,
+	.priority = ADDRCONF_NOTIFY_PRIORITY - 5,
+};
+
+#ifdef CONFIG_SYSCTL
+static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
+					 const char *func, const char *dev_name)
+{
+	static char warncomm[TASK_COMM_LEN];
+	static int warned;
+	if (strcmp(warncomm, current->comm) && warned < 5) {
+		strcpy(warncomm, current->comm);
+		pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n",
+			warncomm, func,
+			dev_name, ctl->procname,
+			dev_name, ctl->procname);
+		warned++;
+	}
+}
+
+int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct net_device *dev = ctl->extra1;
+	struct inet6_dev *idev;
+	int ret;
+
+	if ((strcmp(ctl->procname, "retrans_time") == 0) ||
+	    (strcmp(ctl->procname, "base_reachable_time") == 0))
+		ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
+
+	if (strcmp(ctl->procname, "retrans_time") == 0)
+		ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos);
+
+	else if (strcmp(ctl->procname, "base_reachable_time") == 0)
+		ret = neigh_proc_dointvec_jiffies(ctl, write,
+						  buffer, lenp, ppos);
+
+	else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
+		 (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
+		ret = neigh_proc_dointvec_ms_jiffies(ctl, write,
+						     buffer, lenp, ppos);
+	else
+		ret = -1;
+
+	if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
+		if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
+			idev->nd_parms->reachable_time =
+					neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
+		idev->tstamp = jiffies;
+		inet6_ifinfo_notify(RTM_NEWLINK, idev);
+		in6_dev_put(idev);
+	}
+	return ret;
+}
+
+
+#endif
+
+static int __net_init ndisc_net_init(struct net *net)
+{
+	struct ipv6_pinfo *np;
+	struct sock *sk;
+	int err;
+
+	err = inet_ctl_sock_create(&sk, PF_INET6,
+				   SOCK_RAW, IPPROTO_ICMPV6, net);
+	if (err < 0) {
+		ND_PRINTK(0, err,
+			  "NDISC: Failed to initialize the control socket (err %d)\n",
+			  err);
+		return err;
+	}
+
+	net->ipv6.ndisc_sk = sk;
+
+	np = inet6_sk(sk);
+	np->hop_limit = 255;
+	/* Do not loopback ndisc messages */
+	np->mc_loop = 0;
+
+	return 0;
+}
+
+static void __net_exit ndisc_net_exit(struct net *net)
+{
+	inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
+}
+
+static struct pernet_operations ndisc_net_ops = {
+	.init = ndisc_net_init,
+	.exit = ndisc_net_exit,
+};
+
+int __init ndisc_init(void)
+{
+	int err;
+
+	err = register_pernet_subsys(&ndisc_net_ops);
+	if (err)
+		return err;
+	/*
+	 * Initialize the neighbour table
+	 */
+	neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
+
+#ifdef CONFIG_SYSCTL
+	err = neigh_sysctl_register(NULL, &nd_tbl.parms,
+				    ndisc_ifinfo_sysctl_change);
+	if (err)
+		goto out_unregister_pernet;
+out:
+#endif
+	return err;
+
+#ifdef CONFIG_SYSCTL
+out_unregister_pernet:
+	unregister_pernet_subsys(&ndisc_net_ops);
+	goto out;
+#endif
+}
+
+int __init ndisc_late_init(void)
+{
+	return register_netdevice_notifier(&ndisc_netdev_notifier);
+}
+
+void ndisc_late_cleanup(void)
+{
+	unregister_netdevice_notifier(&ndisc_netdev_notifier);
+}
+
+void ndisc_cleanup(void)
+{
+#ifdef CONFIG_SYSCTL
+	neigh_sysctl_unregister(&nd_tbl.parms);
+#endif
+	neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
+	unregister_pernet_subsys(&ndisc_net_ops);
+}