net/ipv6/datagram.c - linux - Git at Google

 /*
  *	common UDP/RAW code
  *	Linux INET6 implementation
  *
  *	Authors:
  *	Pedro Roque		<roque@di.fc.ul.pt>
  *
  *	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.
  */

 #include <linux/capability.h>
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/interrupt.h>
 #include <linux/socket.h>
 #include <linux/sockios.h>
 #include <linux/in6.h>
 #include <linux/ipv6.h>
 #include <linux/route.h>
 #include <linux/slab.h>
 #include <linux/export.h>

 #include <net/ipv6.h>
 #include <net/ndisc.h>
 #include <net/addrconf.h>
 #include <net/transp_v6.h>
 #include <net/ip6_route.h>
 #include <net/tcp_states.h>
 #include <net/dsfield.h>

 #include <linux/errqueue.h>
 #include <asm/uaccess.h>

 static bool ipv6_mapped_addr_any(const struct in6_addr *a)
 {
 	return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
 }

 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 {
 	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
 	struct inet_sock	*inet = inet_sk(sk);
 	struct ipv6_pinfo	*np = inet6_sk(sk);
 	struct in6_addr	*daddr, *final_p, final;
 	struct dst_entry	*dst;
 	struct flowi6		fl6;
 	struct ip6_flowlabel	*flowlabel = NULL;
 	struct ipv6_txoptions	*opt;
 	int			addr_type;
 	int			err;

 	if (usin->sin6_family == AF_INET) {
 		if (__ipv6_only_sock(sk))
 			return -EAFNOSUPPORT;
 		err = ip4_datagram_connect(sk, uaddr, addr_len);
 		goto ipv4_connected;
 	}

 	if (addr_len < SIN6_LEN_RFC2133)
 		return -EINVAL;

 	if (usin->sin6_family != AF_INET6)
 		return -EAFNOSUPPORT;

 	memset(&fl6, 0, sizeof(fl6));
 	if (np->sndflow) {
 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 			if (flowlabel == NULL)
 				return -EINVAL;
 		}
 	}

 	addr_type = ipv6_addr_type(&usin->sin6_addr);

 	if (addr_type == IPV6_ADDR_ANY) {
 		/*
 		 *	connect to self
 		 */
 		usin->sin6_addr.s6_addr[15] = 0x01;
 	}

 	daddr = &usin->sin6_addr;

 	if (addr_type == IPV6_ADDR_MAPPED) {
 		struct sockaddr_in sin;

 		if (__ipv6_only_sock(sk)) {
 			err = -ENETUNREACH;
 			goto out;
 		}
 		sin.sin_family = AF_INET;
 		sin.sin_addr.s_addr = daddr->s6_addr32[3];
 		sin.sin_port = usin->sin6_port;

 		err = ip4_datagram_connect(sk,
 					   (struct sockaddr *) &sin,
 					   sizeof(sin));

 ipv4_connected:
 		if (err)
 			goto out;

 		ipv6_addr_set_v4mapped(inet->inet_daddr, &sk->sk_v6_daddr);

 		if (ipv6_addr_any(&np->saddr) ||
 		    ipv6_mapped_addr_any(&np->saddr))
 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);

 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr) ||
 		    ipv6_mapped_addr_any(&sk->sk_v6_rcv_saddr)) {
 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
 					       &sk->sk_v6_rcv_saddr);
 			if (sk->sk_prot->rehash)
 				sk->sk_prot->rehash(sk);
 		}

 		goto out;
 	}

 	if (__ipv6_addr_needs_scope_id(addr_type)) {
 		if (addr_len >= sizeof(struct sockaddr_in6) &&
 		    usin->sin6_scope_id) {
 			if (sk->sk_bound_dev_if &&
 			    sk->sk_bound_dev_if != usin->sin6_scope_id) {
 				err = -EINVAL;
 				goto out;
 			}
 			sk->sk_bound_dev_if = usin->sin6_scope_id;
 		}

 		if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
 			sk->sk_bound_dev_if = np->mcast_oif;

 		/* Connect to link-local address requires an interface */
 		if (!sk->sk_bound_dev_if) {
 			err = -EINVAL;
 			goto out;
 		}
 	}

 	sk->sk_v6_daddr = *daddr;
 	np->flow_label = fl6.flowlabel;

 	inet->inet_dport = usin->sin6_port;

 	/*
 	 *	Check for a route to destination an obtain the
 	 *	destination cache for it.
 	 */

 	fl6.flowi6_proto = sk->sk_protocol;
 	fl6.daddr = sk->sk_v6_daddr;
 	fl6.saddr = np->saddr;
 	fl6.flowi6_oif = sk->sk_bound_dev_if;
 	fl6.flowi6_mark = sk->sk_mark;
 	fl6.fl6_dport = inet->inet_dport;
 	fl6.fl6_sport = inet->inet_sport;

 	if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
 		fl6.flowi6_oif = np->mcast_oif;

 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));

 	opt = flowlabel ? flowlabel->opt : np->opt;
 	final_p = fl6_update_dst(&fl6, opt, &final);

 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 	err = 0;
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		goto out;
 	}

 	/* source address lookup done in ip6_dst_lookup */

 	if (ipv6_addr_any(&np->saddr))
 		np->saddr = fl6.saddr;

 	if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
 		sk->sk_v6_rcv_saddr = fl6.saddr;
 		inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 		if (sk->sk_prot->rehash)
 			sk->sk_prot->rehash(sk);
 	}

 	ip6_dst_store(sk, dst,
 		      ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
 		      &sk->sk_v6_daddr : NULL,
 #ifdef CONFIG_IPV6_SUBTREES
 		      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
 		      &np->saddr :
 #endif
 		      NULL);

 	sk->sk_state = TCP_ESTABLISHED;
 	ip6_set_txhash(sk);
 out:
 	fl6_sock_release(flowlabel);
 	return err;
 }
 EXPORT_SYMBOL_GPL(ip6_datagram_connect);

 int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *uaddr,
 				 int addr_len)
 {
 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, uaddr);
 	if (sin6->sin6_family != AF_INET6)
 		return -EAFNOSUPPORT;
 	return ip6_datagram_connect(sk, uaddr, addr_len);
 }
 EXPORT_SYMBOL_GPL(ip6_datagram_connect_v6_only);

 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 		     __be16 port, u32 info, u8 *payload)
 {
 	struct ipv6_pinfo *np  = inet6_sk(sk);
 	struct icmp6hdr *icmph = icmp6_hdr(skb);
 	struct sock_exterr_skb *serr;

 	if (!np->recverr)
 		return;

 	skb = skb_clone(skb, GFP_ATOMIC);
 	if (!skb)
 		return;

 	skb->protocol = htons(ETH_P_IPV6);

 	serr = SKB_EXT_ERR(skb);
 	serr->ee.ee_errno = err;
 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
 	serr->ee.ee_type = icmph->icmp6_type;
 	serr->ee.ee_code = icmph->icmp6_code;
 	serr->ee.ee_pad = 0;
 	serr->ee.ee_info = info;
 	serr->ee.ee_data = 0;
 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
 				  skb_network_header(skb);
 	serr->port = port;

 	__skb_pull(skb, payload - skb->data);
 	skb_reset_transport_header(skb);

 	if (sock_queue_err_skb(sk, skb))
 		kfree_skb(skb);
 }

 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct sock_exterr_skb *serr;
 	struct ipv6hdr *iph;
 	struct sk_buff *skb;

 	if (!np->recverr)
 		return;

 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 	if (!skb)
 		return;

 	skb->protocol = htons(ETH_P_IPV6);

 	skb_put(skb, sizeof(struct ipv6hdr));
 	skb_reset_network_header(skb);
 	iph = ipv6_hdr(skb);
 	iph->daddr = fl6->daddr;

 	serr = SKB_EXT_ERR(skb);
 	serr->ee.ee_errno = err;
 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
 	serr->ee.ee_type = 0;
 	serr->ee.ee_code = 0;
 	serr->ee.ee_pad = 0;
 	serr->ee.ee_info = info;
 	serr->ee.ee_data = 0;
 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
 	serr->port = fl6->fl6_dport;

 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 	skb_reset_transport_header(skb);

 	if (sock_queue_err_skb(sk, skb))
 		kfree_skb(skb);
 }

 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct ipv6hdr *iph;
 	struct sk_buff *skb;
 	struct ip6_mtuinfo *mtu_info;

 	if (!np->rxopt.bits.rxpmtu)
 		return;

 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 	if (!skb)
 		return;

 	skb_put(skb, sizeof(struct ipv6hdr));
 	skb_reset_network_header(skb);
 	iph = ipv6_hdr(skb);
 	iph->daddr = fl6->daddr;

 	mtu_info = IP6CBMTU(skb);

 	mtu_info->ip6m_mtu = mtu;
 	mtu_info->ip6m_addr.sin6_family = AF_INET6;
 	mtu_info->ip6m_addr.sin6_port = 0;
 	mtu_info->ip6m_addr.sin6_flowinfo = 0;
 	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
 	mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;

 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 	skb_reset_transport_header(skb);

 	skb = xchg(&np->rxpmtu, skb);
 	kfree_skb(skb);
 }

 static void ip6_datagram_prepare_pktinfo_errqueue(struct sk_buff *skb)
 {
 	int ifindex = skb->dev ? skb->dev->ifindex : -1;

 	if (skb->protocol == htons(ETH_P_IPV6))
 		IP6CB(skb)->iif = ifindex;
 	else
 		PKTINFO_SKB_CB(skb)->ipi_ifindex = ifindex;
 }

 /*
  *	Handle MSG_ERRQUEUE
  */
 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct sock_exterr_skb *serr;
 	struct sk_buff *skb;
 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
 	struct {
 		struct sock_extended_err ee;
 		struct sockaddr_in6	 offender;
 	} errhdr;
 	int err;
 	int copied;

 	err = -EAGAIN;
 	skb = sock_dequeue_err_skb(sk);
 	if (skb == NULL)
 		goto out;

 	copied = skb->len;
 	if (copied > len) {
 		msg->msg_flags |= MSG_TRUNC;
 		copied = len;
 	}
 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
 	if (err)
 		goto out_free_skb;

 	sock_recv_timestamp(msg, sk, skb);

 	serr = SKB_EXT_ERR(skb);

 	if (sin) {
 		const unsigned char *nh = skb_network_header(skb);
 		sin->sin6_family = AF_INET6;
 		sin->sin6_flowinfo = 0;
 		sin->sin6_port = serr->port;
 		if (skb->protocol == htons(ETH_P_IPV6)) {
 			const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),
 								  struct ipv6hdr, daddr);
 			sin->sin6_addr = ip6h->daddr;
 			if (np->sndflow)
 				sin->sin6_flowinfo = ip6_flowinfo(ip6h);
 			sin->sin6_scope_id =
 				ipv6_iface_scope_id(&sin->sin6_addr,
 						    IP6CB(skb)->iif);
 		} else {
 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
 					       &sin->sin6_addr);
 			sin->sin6_scope_id = 0;
 		}
 		*addr_len = sizeof(*sin);
 	}

 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
 	sin = &errhdr.offender;
 	sin->sin6_family = AF_UNSPEC;
 	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
 		sin->sin6_family = AF_INET6;
 		sin->sin6_flowinfo = 0;
 		sin->sin6_port = 0;
 		if (np->rxopt.all) {
 			if (serr->ee.ee_origin != SO_EE_ORIGIN_ICMP &&
 			    serr->ee.ee_origin != SO_EE_ORIGIN_ICMP6)
 				ip6_datagram_prepare_pktinfo_errqueue(skb);
 			ip6_datagram_recv_common_ctl(sk, msg, skb);
 		}
 		if (skb->protocol == htons(ETH_P_IPV6)) {
 			sin->sin6_addr = ipv6_hdr(skb)->saddr;
 			if (np->rxopt.all)
 				ip6_datagram_recv_specific_ctl(sk, msg, skb);
 			sin->sin6_scope_id =
 				ipv6_iface_scope_id(&sin->sin6_addr,
 						    IP6CB(skb)->iif);
 		} else {
 			struct inet_sock *inet = inet_sk(sk);

 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
 					       &sin->sin6_addr);
 			sin->sin6_scope_id = 0;
 			if (inet->cmsg_flags)
 				ip_cmsg_recv(msg, skb);
 		}
 	}

 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);

 	/* Now we could try to dump offended packet options */

 	msg->msg_flags |= MSG_ERRQUEUE;
 	err = copied;

 out_free_skb:
 	kfree_skb(skb);
 out:
 	return err;
 }
 EXPORT_SYMBOL_GPL(ipv6_recv_error);

 /*
  *	Handle IPV6_RECVPATHMTU
  */
 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
 		     int *addr_len)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct sk_buff *skb;
 	struct ip6_mtuinfo mtu_info;
 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
 	int err;
 	int copied;

 	err = -EAGAIN;
 	skb = xchg(&np->rxpmtu, NULL);
 	if (skb == NULL)
 		goto out;

 	copied = skb->len;
 	if (copied > len) {
 		msg->msg_flags |= MSG_TRUNC;
 		copied = len;
 	}
 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
 	if (err)
 		goto out_free_skb;

 	sock_recv_timestamp(msg, sk, skb);

 	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));

 	if (sin) {
 		sin->sin6_family = AF_INET6;
 		sin->sin6_flowinfo = 0;
 		sin->sin6_port = 0;
 		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
 		sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
 		*addr_len = sizeof(*sin);
 	}

 	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);

 	err = copied;

 out_free_skb:
 	kfree_skb(skb);
 out:
 	return err;
 }


 void ip6_datagram_recv_common_ctl(struct sock *sk, struct msghdr *msg,
 				 struct sk_buff *skb)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	bool is_ipv6 = skb->protocol == htons(ETH_P_IPV6);

 	if (np->rxopt.bits.rxinfo) {
 		struct in6_pktinfo src_info;

 		if (is_ipv6) {
 			src_info.ipi6_ifindex = IP6CB(skb)->iif;
 			src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 		} else {
 			src_info.ipi6_ifindex =
 				PKTINFO_SKB_CB(skb)->ipi_ifindex;
 			ipv6_addr_set_v4mapped(ip_hdr(skb)->daddr,
 					       &src_info.ipi6_addr);
 		}

 		if (src_info.ipi6_ifindex >= 0)
 			put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO,
 				 sizeof(src_info), &src_info);
 	}
 }

 void ip6_datagram_recv_specific_ctl(struct sock *sk, struct msghdr *msg,
 				    struct sk_buff *skb)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct inet6_skb_parm *opt = IP6CB(skb);
 	unsigned char *nh = skb_network_header(skb);

 	if (np->rxopt.bits.rxhlim) {
 		int hlim = ipv6_hdr(skb)->hop_limit;
 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
 	}

 	if (np->rxopt.bits.rxtclass) {
 		int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
 	}

 	if (np->rxopt.bits.rxflow) {
 		__be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
 		if (flowinfo)
 			put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
 	}

 	/* HbH is allowed only once */
 	if (np->rxopt.bits.hopopts && opt->hop) {
 		u8 *ptr = nh + opt->hop;
 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
 	}

 	if (opt->lastopt &&
 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
 		/*
 		 * Silly enough, but we need to reparse in order to
 		 * report extension headers (except for HbH)
 		 * in order.
 		 *
 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
 		 * (and WILL NOT be) defined because
 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
 		 */
 		unsigned int off = sizeof(struct ipv6hdr);
 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;

 		while (off <= opt->lastopt) {
 			unsigned int len;
 			u8 *ptr = nh + off;

 			switch (nexthdr) {
 			case IPPROTO_DSTOPTS:
 				nexthdr = ptr[0];
 				len = (ptr[1] + 1) << 3;
 				if (np->rxopt.bits.dstopts)
 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
 				break;
 			case IPPROTO_ROUTING:
 				nexthdr = ptr[0];
 				len = (ptr[1] + 1) << 3;
 				if (np->rxopt.bits.srcrt)
 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
 				break;
 			case IPPROTO_AH:
 				nexthdr = ptr[0];
 				len = (ptr[1] + 2) << 2;
 				break;
 			default:
 				nexthdr = ptr[0];
 				len = (ptr[1] + 1) << 3;
 				break;
 			}

 			off += len;
 		}
 	}

 	/* socket options in old style */
 	if (np->rxopt.bits.rxoinfo) {
 		struct in6_pktinfo src_info;

 		src_info.ipi6_ifindex = opt->iif;
 		src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
 	}
 	if (np->rxopt.bits.rxohlim) {
 		int hlim = ipv6_hdr(skb)->hop_limit;
 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
 	}
 	if (np->rxopt.bits.ohopopts && opt->hop) {
 		u8 *ptr = nh + opt->hop;
 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
 	}
 	if (np->rxopt.bits.odstopts && opt->dst0) {
 		u8 *ptr = nh + opt->dst0;
 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 	}
 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
 	}
 	if (np->rxopt.bits.odstopts && opt->dst1) {
 		u8 *ptr = nh + opt->dst1;
 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 	}
 	if (np->rxopt.bits.rxorigdstaddr) {
 		struct sockaddr_in6 sin6;
 		__be16 *ports = (__be16 *) skb_transport_header(skb);

 		if (skb_transport_offset(skb) + 4 <= skb->len) {
 			/* All current transport protocols have the port numbers in the
 			 * first four bytes of the transport header and this function is
 			 * written with this assumption in mind.
 			 */

 			sin6.sin6_family = AF_INET6;
 			sin6.sin6_addr = ipv6_hdr(skb)->daddr;
 			sin6.sin6_port = ports[1];
 			sin6.sin6_flowinfo = 0;
 			sin6.sin6_scope_id =
 				ipv6_iface_scope_id(&ipv6_hdr(skb)->daddr,
 						    opt->iif);

 			put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
 		}
 	}
 }

 void ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
 			  struct sk_buff *skb)
 {
 	ip6_datagram_recv_common_ctl(sk, msg, skb);
 	ip6_datagram_recv_specific_ctl(sk, msg, skb);
 }
 EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);

 int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
 			  struct msghdr *msg, struct flowi6 *fl6,
 			  struct ipv6_txoptions *opt,
 			  int *hlimit, int *tclass, int *dontfrag)
 {
 	struct in6_pktinfo *src_info;
 	struct cmsghdr *cmsg;
 	struct ipv6_rt_hdr *rthdr;
 	struct ipv6_opt_hdr *hdr;
 	int len;
 	int err = 0;

 	for_each_cmsghdr(cmsg, msg) {
 		int addr_type;

 		if (!CMSG_OK(msg, cmsg)) {
 			err = -EINVAL;
 			goto exit_f;
 		}

 		if (cmsg->cmsg_level != SOL_IPV6)
 			continue;

 		switch (cmsg->cmsg_type) {
 		case IPV6_PKTINFO:
 		case IPV6_2292PKTINFO:
 		    {
 			struct net_device *dev = NULL;

 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);

 			if (src_info->ipi6_ifindex) {
 				if (fl6->flowi6_oif &&
 				    src_info->ipi6_ifindex != fl6->flowi6_oif)
 					return -EINVAL;
 				fl6->flowi6_oif = src_info->ipi6_ifindex;
 			}

 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);

 			rcu_read_lock();
 			if (fl6->flowi6_oif) {
 				dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 				if (!dev) {
 					rcu_read_unlock();
 					return -ENODEV;
 				}
 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
 				rcu_read_unlock();
 				return -EINVAL;
 			}

 			if (addr_type != IPV6_ADDR_ANY) {
 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
 				if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
 				    !ipv6_chk_addr(net, &src_info->ipi6_addr,
 						   strict ? dev : NULL, 0) &&
 				    !ipv6_chk_acast_addr_src(net, dev,
 							     &src_info->ipi6_addr))
 					err = -EINVAL;
 				else
 					fl6->saddr = src_info->ipi6_addr;
 			}

 			rcu_read_unlock();

 			if (err)
 				goto exit_f;

 			break;
 		    }

 		case IPV6_FLOWINFO:
 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
 				if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
 					err = -EINVAL;
 					goto exit_f;
 				}
 			}
 			fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
 			break;

 		case IPV6_2292HOPOPTS:
 		case IPV6_HOPOPTS:
 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 			len = ((hdr->hdrlen + 1) << 3);
 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
 				err = -EINVAL;
 				goto exit_f;
 			}
 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 				err = -EPERM;
 				goto exit_f;
 			}
 			opt->opt_nflen += len;
 			opt->hopopt = hdr;
 			break;

 		case IPV6_2292DSTOPTS:
 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 			len = ((hdr->hdrlen + 1) << 3);
 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
 				err = -EINVAL;
 				goto exit_f;
 			}
 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 				err = -EPERM;
 				goto exit_f;
 			}
 			if (opt->dst1opt) {
 				err = -EINVAL;
 				goto exit_f;
 			}
 			opt->opt_flen += len;
 			opt->dst1opt = hdr;
 			break;

 		case IPV6_DSTOPTS:
 		case IPV6_RTHDRDSTOPTS:
 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 			len = ((hdr->hdrlen + 1) << 3);
 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
 				err = -EINVAL;
 				goto exit_f;
 			}
 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 				err = -EPERM;
 				goto exit_f;
 			}
 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
 				opt->opt_flen += len;
 				opt->dst1opt = hdr;
 			} else {
 				opt->opt_nflen += len;
 				opt->dst0opt = hdr;
 			}
 			break;

 		case IPV6_2292RTHDR:
 		case IPV6_RTHDR:
 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);

 			switch (rthdr->type) {
 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 			case IPV6_SRCRT_TYPE_2:
 				if (rthdr->hdrlen != 2 ||
 				    rthdr->segments_left != 1) {
 					err = -EINVAL;
 					goto exit_f;
 				}
 				break;
 #endif
 			default:
 				err = -EINVAL;
 				goto exit_f;
 			}

 			len = ((rthdr->hdrlen + 1) << 3);

 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			/* segments left must also match */
 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			opt->opt_nflen += len;
 			opt->srcrt = rthdr;

 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);

 				opt->opt_nflen += dsthdrlen;
 				opt->dst0opt = opt->dst1opt;
 				opt->dst1opt = NULL;
 				opt->opt_flen -= dsthdrlen;
 			}

 			break;

 		case IPV6_2292HOPLIMIT:
 		case IPV6_HOPLIMIT:
 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			*hlimit = *(int *)CMSG_DATA(cmsg);
 			if (*hlimit < -1 || *hlimit > 0xff) {
 				err = -EINVAL;
 				goto exit_f;
 			}

 			break;

 		case IPV6_TCLASS:
 		    {
 			int tc;

 			err = -EINVAL;
 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 				goto exit_f;

 			tc = *(int *)CMSG_DATA(cmsg);
 			if (tc < -1 || tc > 0xff)
 				goto exit_f;

 			err = 0;
 			*tclass = tc;

 			break;
 		    }

 		case IPV6_DONTFRAG:
 		    {
 			int df;

 			err = -EINVAL;
 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 				goto exit_f;

 			df = *(int *)CMSG_DATA(cmsg);
 			if (df < 0 || df > 1)
 				goto exit_f;

 			err = 0;
 			*dontfrag = df;

 			break;
 		    }
 		default:
 			net_dbg_ratelimited("invalid cmsg type: %d\n",
 					    cmsg->cmsg_type);
 			err = -EINVAL;
 			goto exit_f;
 		}
 	}

 exit_f:
 	return err;
 }
 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);

 void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
 			     __u16 srcp, __u16 destp, int bucket)
 {
 	const struct in6_addr *dest, *src;

 	dest  = &sp->sk_v6_daddr;
 	src   = &sp->sk_v6_rcv_saddr;
 	seq_printf(seq,
 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d\n",
 		   bucket,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
 		   dest->s6_addr32[0], dest->s6_addr32[1],
 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
 		   sp->sk_state,
 		   sk_wmem_alloc_get(sp),
 		   sk_rmem_alloc_get(sp),
 		   0, 0L, 0,
 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
 		   0,
 		   sock_i_ino(sp),
 		   atomic_read(&sp->sk_refcnt), sp,
 		   atomic_read(&sp->sk_drops));
 }
	/*
	* common UDP/RAW code
	* Linux INET6 implementation
	*
	* Authors:
	* Pedro Roque <roque@di.fc.ul.pt>
	*
	* 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.
	*/

	#include <linux/capability.h>
	#include <linux/errno.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/interrupt.h>
	#include <linux/socket.h>
	#include <linux/sockios.h>
	#include <linux/in6.h>
	#include <linux/ipv6.h>
	#include <linux/route.h>
	#include <linux/slab.h>
	#include <linux/export.h>

	#include <net/ipv6.h>
	#include <net/ndisc.h>
	#include <net/addrconf.h>
	#include <net/transp_v6.h>
	#include <net/ip6_route.h>
	#include <net/tcp_states.h>
	#include <net/dsfield.h>

	#include <linux/errqueue.h>
	#include <asm/uaccess.h>

	static bool ipv6_mapped_addr_any(const struct in6_addr *a)
	{
	return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
	}

	int ip6_datagram_connect(struct sock sk, struct sockaddr uaddr, int addr_len)
	{
	struct sockaddr_in6 usin = (struct sockaddr_in6 ) uaddr;
	struct inet_sock *inet = inet_sk(sk);
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct in6_addr daddr, final_p, final;
	struct dst_entry *dst;
	struct flowi6 fl6;
	struct ip6_flowlabel *flowlabel = NULL;
	struct ipv6_txoptions *opt;
	int addr_type;
	int err;

	if (usin->sin6_family == AF_INET) {
	if (__ipv6_only_sock(sk))
	return -EAFNOSUPPORT;
	err = ip4_datagram_connect(sk, uaddr, addr_len);
	goto ipv4_connected;
	}

	if (addr_len < SIN6_LEN_RFC2133)
	return -EINVAL;

	if (usin->sin6_family != AF_INET6)
	return -EAFNOSUPPORT;

	memset(&fl6, 0, sizeof(fl6));
	if (np->sndflow) {
	fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
	if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
	flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
	if (flowlabel == NULL)
	return -EINVAL;
	}
	}

	addr_type = ipv6_addr_type(&usin->sin6_addr);

	if (addr_type == IPV6_ADDR_ANY) {
	/*
	* connect to self
	*/
	usin->sin6_addr.s6_addr[15] = 0x01;
	}

	daddr = &usin->sin6_addr;

	if (addr_type == IPV6_ADDR_MAPPED) {
	struct sockaddr_in sin;

	if (__ipv6_only_sock(sk)) {
	err = -ENETUNREACH;
	goto out;
	}
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = daddr->s6_addr32[3];
	sin.sin_port = usin->sin6_port;

	err = ip4_datagram_connect(sk,
	(struct sockaddr *) &sin,
	sizeof(sin));

	ipv4_connected:
	if (err)
	goto out;

	ipv6_addr_set_v4mapped(inet->inet_daddr, &sk->sk_v6_daddr);

	if (ipv6_addr_any(&np->saddr) \|\|
	ipv6_mapped_addr_any(&np->saddr))
	ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);

	if (ipv6_addr_any(&sk->sk_v6_rcv_saddr) \|\|
	ipv6_mapped_addr_any(&sk->sk_v6_rcv_saddr)) {
	ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
	&sk->sk_v6_rcv_saddr);
	if (sk->sk_prot->rehash)
	sk->sk_prot->rehash(sk);
	}

	goto out;
	}

	if (__ipv6_addr_needs_scope_id(addr_type)) {
	if (addr_len >= sizeof(struct sockaddr_in6) &&
	usin->sin6_scope_id) {
	if (sk->sk_bound_dev_if &&
	sk->sk_bound_dev_if != usin->sin6_scope_id) {
	err = -EINVAL;
	goto out;
	}
	sk->sk_bound_dev_if = usin->sin6_scope_id;
	}

	if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
	sk->sk_bound_dev_if = np->mcast_oif;

	/* Connect to link-local address requires an interface */
	if (!sk->sk_bound_dev_if) {
	err = -EINVAL;
	goto out;
	}
	}

	sk->sk_v6_daddr = *daddr;
	np->flow_label = fl6.flowlabel;

	inet->inet_dport = usin->sin6_port;

	/*
	* Check for a route to destination an obtain the
	* destination cache for it.
	*/

	fl6.flowi6_proto = sk->sk_protocol;
	fl6.daddr = sk->sk_v6_daddr;
	fl6.saddr = np->saddr;
	fl6.flowi6_oif = sk->sk_bound_dev_if;
	fl6.flowi6_mark = sk->sk_mark;
	fl6.fl6_dport = inet->inet_dport;
	fl6.fl6_sport = inet->inet_sport;

	if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
	fl6.flowi6_oif = np->mcast_oif;

	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));

	opt = flowlabel ? flowlabel->opt : np->opt;
	final_p = fl6_update_dst(&fl6, opt, &final);

	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
	err = 0;
	if (IS_ERR(dst)) {
	err = PTR_ERR(dst);
	goto out;
	}

	/* source address lookup done in ip6_dst_lookup */

	if (ipv6_addr_any(&np->saddr))
	np->saddr = fl6.saddr;

	if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
	sk->sk_v6_rcv_saddr = fl6.saddr;
	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
	if (sk->sk_prot->rehash)
	sk->sk_prot->rehash(sk);
	}

	ip6_dst_store(sk, dst,
	ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
	&sk->sk_v6_daddr : NULL,
	#ifdef CONFIG_IPV6_SUBTREES
	ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
	&np->saddr :
	#endif
	NULL);

	sk->sk_state = TCP_ESTABLISHED;
	ip6_set_txhash(sk);
	out:
	fl6_sock_release(flowlabel);
	return err;
	}
	EXPORT_SYMBOL_GPL(ip6_datagram_connect);

	int ip6_datagram_connect_v6_only(struct sock sk, struct sockaddr uaddr,
	int addr_len)
	{
	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, uaddr);
	if (sin6->sin6_family != AF_INET6)
	return -EAFNOSUPPORT;
	return ip6_datagram_connect(sk, uaddr, addr_len);
	}
	EXPORT_SYMBOL_GPL(ip6_datagram_connect_v6_only);

	void ipv6_icmp_error(struct sock sk, struct sk_buff skb, int err,
	__be16 port, u32 info, u8 *payload)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct icmp6hdr *icmph = icmp6_hdr(skb);
	struct sock_exterr_skb *serr;

	if (!np->recverr)
	return;

	skb = skb_clone(skb, GFP_ATOMIC);
	if (!skb)
	return;

	skb->protocol = htons(ETH_P_IPV6);

	serr = SKB_EXT_ERR(skb);
	serr->ee.ee_errno = err;
	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
	serr->ee.ee_type = icmph->icmp6_type;
	serr->ee.ee_code = icmph->icmp6_code;
	serr->ee.ee_pad = 0;
	serr->ee.ee_info = info;
	serr->ee.ee_data = 0;
	serr->addr_offset = (u8 )&(((struct ipv6hdr )(icmph + 1))->daddr) -
	skb_network_header(skb);
	serr->port = port;

	__skb_pull(skb, payload - skb->data);
	skb_reset_transport_header(skb);

	if (sock_queue_err_skb(sk, skb))
	kfree_skb(skb);
	}

	void ipv6_local_error(struct sock sk, int err, struct flowi6 fl6, u32 info)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sock_exterr_skb *serr;
	struct ipv6hdr *iph;
	struct sk_buff *skb;

	if (!np->recverr)
	return;

	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
	if (!skb)
	return;

	skb->protocol = htons(ETH_P_IPV6);

	skb_put(skb, sizeof(struct ipv6hdr));
	skb_reset_network_header(skb);
	iph = ipv6_hdr(skb);
	iph->daddr = fl6->daddr;

	serr = SKB_EXT_ERR(skb);
	serr->ee.ee_errno = err;
	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
	serr->ee.ee_type = 0;
	serr->ee.ee_code = 0;
	serr->ee.ee_pad = 0;
	serr->ee.ee_info = info;
	serr->ee.ee_data = 0;
	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
	serr->port = fl6->fl6_dport;

	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
	skb_reset_transport_header(skb);

	if (sock_queue_err_skb(sk, skb))
	kfree_skb(skb);
	}

	void ipv6_local_rxpmtu(struct sock sk, struct flowi6 fl6, u32 mtu)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct ipv6hdr *iph;
	struct sk_buff *skb;
	struct ip6_mtuinfo *mtu_info;

	if (!np->rxopt.bits.rxpmtu)
	return;

	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
	if (!skb)
	return;

	skb_put(skb, sizeof(struct ipv6hdr));
	skb_reset_network_header(skb);
	iph = ipv6_hdr(skb);
	iph->daddr = fl6->daddr;

	mtu_info = IP6CBMTU(skb);

	mtu_info->ip6m_mtu = mtu;
	mtu_info->ip6m_addr.sin6_family = AF_INET6;
	mtu_info->ip6m_addr.sin6_port = 0;
	mtu_info->ip6m_addr.sin6_flowinfo = 0;
	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
	mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;

	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
	skb_reset_transport_header(skb);

	skb = xchg(&np->rxpmtu, skb);
	kfree_skb(skb);
	}

	static void ip6_datagram_prepare_pktinfo_errqueue(struct sk_buff *skb)
	{
	int ifindex = skb->dev ? skb->dev->ifindex : -1;

	if (skb->protocol == htons(ETH_P_IPV6))
	IP6CB(skb)->iif = ifindex;
	else
	PKTINFO_SKB_CB(skb)->ipi_ifindex = ifindex;
	}

	/*
	* Handle MSG_ERRQUEUE
	*/
	int ipv6_recv_error(struct sock sk, struct msghdr msg, int len, int *addr_len)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sock_exterr_skb *serr;
	struct sk_buff *skb;
	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
	struct {
	struct sock_extended_err ee;
	struct sockaddr_in6 offender;
	} errhdr;
	int err;
	int copied;

	err = -EAGAIN;
	skb = sock_dequeue_err_skb(sk);
	if (skb == NULL)
	goto out;

	copied = skb->len;
	if (copied > len) {
	msg->msg_flags \|= MSG_TRUNC;
	copied = len;
	}
	err = skb_copy_datagram_msg(skb, 0, msg, copied);
	if (err)
	goto out_free_skb;

	sock_recv_timestamp(msg, sk, skb);

	serr = SKB_EXT_ERR(skb);

	if (sin) {
	const unsigned char *nh = skb_network_header(skb);
	sin->sin6_family = AF_INET6;
	sin->sin6_flowinfo = 0;
	sin->sin6_port = serr->port;
	if (skb->protocol == htons(ETH_P_IPV6)) {
	const struct ipv6hdr ip6h = container_of((struct in6_addr )(nh + serr->addr_offset),
	struct ipv6hdr, daddr);
	sin->sin6_addr = ip6h->daddr;
	if (np->sndflow)
	sin->sin6_flowinfo = ip6_flowinfo(ip6h);
	sin->sin6_scope_id =
	ipv6_iface_scope_id(&sin->sin6_addr,
	IP6CB(skb)->iif);
	} else {
	ipv6_addr_set_v4mapped((__be32 )(nh + serr->addr_offset),
	&sin->sin6_addr);
	sin->sin6_scope_id = 0;
	}
	addr_len = sizeof(sin);
	}

	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
	sin = &errhdr.offender;
	sin->sin6_family = AF_UNSPEC;
	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
	sin->sin6_family = AF_INET6;
	sin->sin6_flowinfo = 0;
	sin->sin6_port = 0;
	if (np->rxopt.all) {
	if (serr->ee.ee_origin != SO_EE_ORIGIN_ICMP &&
	serr->ee.ee_origin != SO_EE_ORIGIN_ICMP6)
	ip6_datagram_prepare_pktinfo_errqueue(skb);
	ip6_datagram_recv_common_ctl(sk, msg, skb);
	}
	if (skb->protocol == htons(ETH_P_IPV6)) {
	sin->sin6_addr = ipv6_hdr(skb)->saddr;
	if (np->rxopt.all)
	ip6_datagram_recv_specific_ctl(sk, msg, skb);
	sin->sin6_scope_id =
	ipv6_iface_scope_id(&sin->sin6_addr,
	IP6CB(skb)->iif);
	} else {
	struct inet_sock *inet = inet_sk(sk);

	ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
	&sin->sin6_addr);
	sin->sin6_scope_id = 0;
	if (inet->cmsg_flags)
	ip_cmsg_recv(msg, skb);
	}
	}

	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);

	/* Now we could try to dump offended packet options */

	msg->msg_flags \|= MSG_ERRQUEUE;
	err = copied;

	out_free_skb:
	kfree_skb(skb);
	out:
	return err;
	}
	EXPORT_SYMBOL_GPL(ipv6_recv_error);

	/*
	* Handle IPV6_RECVPATHMTU
	*/
	int ipv6_recv_rxpmtu(struct sock sk, struct msghdr msg, int len,
	int *addr_len)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sk_buff *skb;
	struct ip6_mtuinfo mtu_info;
	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
	int err;
	int copied;

	err = -EAGAIN;
	skb = xchg(&np->rxpmtu, NULL);
	if (skb == NULL)
	goto out;

	copied = skb->len;
	if (copied > len) {
	msg->msg_flags \|= MSG_TRUNC;
	copied = len;
	}
	err = skb_copy_datagram_msg(skb, 0, msg, copied);
	if (err)
	goto out_free_skb;

	sock_recv_timestamp(msg, sk, skb);

	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));

	if (sin) {
	sin->sin6_family = AF_INET6;
	sin->sin6_flowinfo = 0;
	sin->sin6_port = 0;
	sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
	sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
	addr_len = sizeof(sin);
	}

	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);

	err = copied;

	out_free_skb:
	kfree_skb(skb);
	out:
	return err;
	}


	void ip6_datagram_recv_common_ctl(struct sock sk, struct msghdr msg,
	struct sk_buff *skb)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	bool is_ipv6 = skb->protocol == htons(ETH_P_IPV6);

	if (np->rxopt.bits.rxinfo) {
	struct in6_pktinfo src_info;

	if (is_ipv6) {
	src_info.ipi6_ifindex = IP6CB(skb)->iif;
	src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
	} else {
	src_info.ipi6_ifindex =
	PKTINFO_SKB_CB(skb)->ipi_ifindex;
	ipv6_addr_set_v4mapped(ip_hdr(skb)->daddr,
	&src_info.ipi6_addr);
	}

	if (src_info.ipi6_ifindex >= 0)
	put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO,
	sizeof(src_info), &src_info);
	}
	}

	void ip6_datagram_recv_specific_ctl(struct sock sk, struct msghdr msg,
	struct sk_buff *skb)
	{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct inet6_skb_parm *opt = IP6CB(skb);
	unsigned char *nh = skb_network_header(skb);

	if (np->rxopt.bits.rxhlim) {
	int hlim = ipv6_hdr(skb)->hop_limit;
	put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
	}

	if (np->rxopt.bits.rxtclass) {
	int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
	put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
	}

	if (np->rxopt.bits.rxflow) {
	__be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
	if (flowinfo)
	put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
	}

	/* HbH is allowed only once */
	if (np->rxopt.bits.hopopts && opt->hop) {
	u8 *ptr = nh + opt->hop;
	put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
	}

	if (opt->lastopt &&
	(np->rxopt.bits.dstopts \|\| np->rxopt.bits.srcrt)) {
	/*
	* Silly enough, but we need to reparse in order to
	* report extension headers (except for HbH)
	* in order.
	*
	* Also note that IPV6_RECVRTHDRDSTOPTS is NOT
	* (and WILL NOT be) defined because
	* IPV6_RECVDSTOPTS is more generic. --yoshfuji
	*/
	unsigned int off = sizeof(struct ipv6hdr);
	u8 nexthdr = ipv6_hdr(skb)->nexthdr;

	while (off <= opt->lastopt) {
	unsigned int len;
	u8 *ptr = nh + off;

	switch (nexthdr) {
	case IPPROTO_DSTOPTS:
	nexthdr = ptr[0];
	len = (ptr[1] + 1) << 3;
	if (np->rxopt.bits.dstopts)
	put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
	break;
	case IPPROTO_ROUTING:
	nexthdr = ptr[0];
	len = (ptr[1] + 1) << 3;
	if (np->rxopt.bits.srcrt)
	put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
	break;
	case IPPROTO_AH:
	nexthdr = ptr[0];
	len = (ptr[1] + 2) << 2;
	break;
	default:
	nexthdr = ptr[0];
	len = (ptr[1] + 1) << 3;
	break;
	}

	off += len;
	}
	}

	/* socket options in old style */
	if (np->rxopt.bits.rxoinfo) {
	struct in6_pktinfo src_info;

	src_info.ipi6_ifindex = opt->iif;
	src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
	put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
	}
	if (np->rxopt.bits.rxohlim) {
	int hlim = ipv6_hdr(skb)->hop_limit;
	put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
	}
	if (np->rxopt.bits.ohopopts && opt->hop) {
	u8 *ptr = nh + opt->hop;
	put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
	}
	if (np->rxopt.bits.odstopts && opt->dst0) {
	u8 *ptr = nh + opt->dst0;
	put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
	}
	if (np->rxopt.bits.osrcrt && opt->srcrt) {
	struct ipv6_rt_hdr rthdr = (struct ipv6_rt_hdr )(nh + opt->srcrt);
	put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
	}
	if (np->rxopt.bits.odstopts && opt->dst1) {
	u8 *ptr = nh + opt->dst1;
	put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
	}
	if (np->rxopt.bits.rxorigdstaddr) {
	struct sockaddr_in6 sin6;
	__be16 ports = (__be16 ) skb_transport_header(skb);

	if (skb_transport_offset(skb) + 4 <= skb->len) {
	/* All current transport protocols have the port numbers in the
	* first four bytes of the transport header and this function is
	* written with this assumption in mind.
	*/

	sin6.sin6_family = AF_INET6;
	sin6.sin6_addr = ipv6_hdr(skb)->daddr;
	sin6.sin6_port = ports[1];
	sin6.sin6_flowinfo = 0;
	sin6.sin6_scope_id =
	ipv6_iface_scope_id(&ipv6_hdr(skb)->daddr,
	opt->iif);

	put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
	}
	}
	}

	void ip6_datagram_recv_ctl(struct sock sk, struct msghdr msg,
	struct sk_buff *skb)
	{
	ip6_datagram_recv_common_ctl(sk, msg, skb);
	ip6_datagram_recv_specific_ctl(sk, msg, skb);
	}
	EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);

	int ip6_datagram_send_ctl(struct net net, struct sock sk,
	struct msghdr msg, struct flowi6 fl6,
	struct ipv6_txoptions *opt,
	int hlimit, int tclass, int *dontfrag)
	{
	struct in6_pktinfo *src_info;
	struct cmsghdr *cmsg;
	struct ipv6_rt_hdr *rthdr;
	struct ipv6_opt_hdr *hdr;
	int len;
	int err = 0;

	for_each_cmsghdr(cmsg, msg) {
	int addr_type;

	if (!CMSG_OK(msg, cmsg)) {
	err = -EINVAL;
	goto exit_f;
	}

	if (cmsg->cmsg_level != SOL_IPV6)
	continue;

	switch (cmsg->cmsg_type) {
	case IPV6_PKTINFO:
	case IPV6_2292PKTINFO:
	{
	struct net_device *dev = NULL;

	if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
	err = -EINVAL;
	goto exit_f;
	}

	src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);

	if (src_info->ipi6_ifindex) {
	if (fl6->flowi6_oif &&
	src_info->ipi6_ifindex != fl6->flowi6_oif)
	return -EINVAL;
	fl6->flowi6_oif = src_info->ipi6_ifindex;
	}

	addr_type = __ipv6_addr_type(&src_info->ipi6_addr);

	rcu_read_lock();
	if (fl6->flowi6_oif) {
	dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
	if (!dev) {
	rcu_read_unlock();
	return -ENODEV;
	}
	} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
	rcu_read_unlock();
	return -EINVAL;
	}

	if (addr_type != IPV6_ADDR_ANY) {
	int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
	if (!(inet_sk(sk)->freebind \|\| inet_sk(sk)->transparent) &&
	!ipv6_chk_addr(net, &src_info->ipi6_addr,
	strict ? dev : NULL, 0) &&
	!ipv6_chk_acast_addr_src(net, dev,
	&src_info->ipi6_addr))
	err = -EINVAL;
	else
	fl6->saddr = src_info->ipi6_addr;
	}

	rcu_read_unlock();

	if (err)
	goto exit_f;

	break;
	}

	case IPV6_FLOWINFO:
	if (cmsg->cmsg_len < CMSG_LEN(4)) {
	err = -EINVAL;
	goto exit_f;
	}

	if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
	if ((fl6->flowlabel^(__be32 )CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
	err = -EINVAL;
	goto exit_f;
	}
	}
	fl6->flowlabel = IPV6_FLOWINFO_MASK & (__be32 )CMSG_DATA(cmsg);
	break;

	case IPV6_2292HOPOPTS:
	case IPV6_HOPOPTS:
	if (opt->hopopt \|\| cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
	err = -EINVAL;
	goto exit_f;
	}

	hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
	len = ((hdr->hdrlen + 1) << 3);
	if (cmsg->cmsg_len < CMSG_LEN(len)) {
	err = -EINVAL;
	goto exit_f;
	}
	if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
	err = -EPERM;
	goto exit_f;
	}
	opt->opt_nflen += len;
	opt->hopopt = hdr;
	break;

	case IPV6_2292DSTOPTS:
	if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
	err = -EINVAL;
	goto exit_f;
	}

	hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
	len = ((hdr->hdrlen + 1) << 3);
	if (cmsg->cmsg_len < CMSG_LEN(len)) {
	err = -EINVAL;
	goto exit_f;
	}
	if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
	err = -EPERM;
	goto exit_f;
	}
	if (opt->dst1opt) {
	err = -EINVAL;
	goto exit_f;
	}
	opt->opt_flen += len;
	opt->dst1opt = hdr;
	break;

	case IPV6_DSTOPTS:
	case IPV6_RTHDRDSTOPTS:
	if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
	err = -EINVAL;
	goto exit_f;
	}

	hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
	len = ((hdr->hdrlen + 1) << 3);
	if (cmsg->cmsg_len < CMSG_LEN(len)) {
	err = -EINVAL;
	goto exit_f;
	}
	if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
	err = -EPERM;
	goto exit_f;
	}
	if (cmsg->cmsg_type == IPV6_DSTOPTS) {
	opt->opt_flen += len;
	opt->dst1opt = hdr;
	} else {
	opt->opt_nflen += len;
	opt->dst0opt = hdr;
	}
	break;

	case IPV6_2292RTHDR:
	case IPV6_RTHDR:
	if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
	err = -EINVAL;
	goto exit_f;
	}

	rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);

	switch (rthdr->type) {
	#if IS_ENABLED(CONFIG_IPV6_MIP6)
	case IPV6_SRCRT_TYPE_2:
	if (rthdr->hdrlen != 2 \|\|
	rthdr->segments_left != 1) {
	err = -EINVAL;
	goto exit_f;
	}
	break;
	#endif
	default:
	err = -EINVAL;
	goto exit_f;
	}

	len = ((rthdr->hdrlen + 1) << 3);

	if (cmsg->cmsg_len < CMSG_LEN(len)) {
	err = -EINVAL;
	goto exit_f;
	}

	/* segments left must also match */
	if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
	err = -EINVAL;
	goto exit_f;
	}

	opt->opt_nflen += len;
	opt->srcrt = rthdr;

	if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
	int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);

	opt->opt_nflen += dsthdrlen;
	opt->dst0opt = opt->dst1opt;
	opt->dst1opt = NULL;
	opt->opt_flen -= dsthdrlen;
	}

	break;

	case IPV6_2292HOPLIMIT:
	case IPV6_HOPLIMIT:
	if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
	err = -EINVAL;
	goto exit_f;
	}

	hlimit = (int *)CMSG_DATA(cmsg);
	if (hlimit < -1 \|\| hlimit > 0xff) {
	err = -EINVAL;
	goto exit_f;
	}

	break;

	case IPV6_TCLASS:
	{
	int tc;

	err = -EINVAL;
	if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
	goto exit_f;

	tc = (int )CMSG_DATA(cmsg);
	if (tc < -1 \|\| tc > 0xff)
	goto exit_f;

	err = 0;
	*tclass = tc;

	break;
	}

	case IPV6_DONTFRAG:
	{
	int df;

	err = -EINVAL;
	if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
	goto exit_f;

	df = (int )CMSG_DATA(cmsg);
	if (df < 0 \|\| df > 1)
	goto exit_f;

	err = 0;
	*dontfrag = df;

	break;
	}
	default:
	net_dbg_ratelimited("invalid cmsg type: %d\n",
	cmsg->cmsg_type);
	err = -EINVAL;
	goto exit_f;
	}
	}

	exit_f:
	return err;
	}
	EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);

	void ip6_dgram_sock_seq_show(struct seq_file seq, struct sock sp,
	__u16 srcp, __u16 destp, int bucket)
	{
	const struct in6_addr dest, src;

	dest = &sp->sk_v6_daddr;
	src = &sp->sk_v6_rcv_saddr;
	seq_printf(seq,
	"%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
	"%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d\n",
	bucket,
	src->s6_addr32[0], src->s6_addr32[1],
	src->s6_addr32[2], src->s6_addr32[3], srcp,
	dest->s6_addr32[0], dest->s6_addr32[1],
	dest->s6_addr32[2], dest->s6_addr32[3], destp,
	sp->sk_state,
	sk_wmem_alloc_get(sp),
	sk_rmem_alloc_get(sp),
	0, 0L, 0,
	from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
	0,
	sock_i_ino(sp),
	atomic_read(&sp->sk_refcnt), sp,
	atomic_read(&sp->sk_drops));
	}