text: /*
   *	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);
  }
  
  static 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;
  			usin->sin6_addr = flowlabel->dst;
  		}
  	}
  
  	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, &np->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(&np->rcv_saddr) ||
  		    ipv6_mapped_addr_any(&np->rcv_saddr)) {
  			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
  					       &np->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;
  		}
  	}
  
  	np->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 = np->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;
  	fl6.flowi6_uid = sock_i_uid(sk);
  
  	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, true);
  	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(&np->rcv_saddr)) {
  		np->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, &np->daddr) ?
  		      &np->daddr : NULL,
  #ifdef CONFIG_IPV6_SUBTREES
  		      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
  		      &np->saddr :
  #endif
  		      NULL);
  
  	sk->sk_state = TCP_ESTABLISHED;
  out:
  	fl6_sock_release(flowlabel);
  	return err;
  }
  
  int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
  {
  	int res;
  
  	lock_sock(sk);
  	res = __ip6_datagram_connect(sk, uaddr, addr_len);
  	release_sock(sk);
  	return res;
  }
  EXPORT_SYMBOL_GPL(ip6_datagram_connect);
  
  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);
  }
  
  /*
   *	Handle MSG_ERRQUEUE
   */
  int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct sock_exterr_skb *serr;
  	struct sk_buff *skb, *skb2;
  	struct sockaddr_in6 *sin;
  	struct {
  		struct sock_extended_err ee;
  		struct sockaddr_in6	 offender;
  	} errhdr;
  	int err;
  	int copied;
  
  	err = -EAGAIN;
  	skb = skb_dequeue(&sk->sk_error_queue);
  	if (skb == NULL)
  		goto out;
  
  	copied = skb->len;
  	if (copied > len) {
  		msg->msg_flags |= MSG_TRUNC;
  		copied = len;
  	}
  	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
  	if (err)
  		goto out_free_skb;
  
  	sock_recv_timestamp(msg, sk, skb);
  
  	serr = SKB_EXT_ERR(skb);
  
  	sin = (struct sockaddr_in6 *)msg->msg_name;
  	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;
  		}
  	}
  
  	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
  	sin = &errhdr.offender;
  	memset(sin, 0, sizeof(*sin));
  
  	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
  		sin->sin6_family = AF_INET6;
  		if (skb->protocol == htons(ETH_P_IPV6)) {
  			sin->sin6_addr = ipv6_hdr(skb)->saddr;
  			if (np->rxopt.all)
  				ip6_datagram_recv_ctl(sk, msg, skb);
  			sin->sin6_scope_id =
  				ipv6_iface_scope_id(&sin->sin6_addr,
  						    IP6CB(skb)->iif);
  		} else {
  			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
  					       &sin->sin6_addr);
  			if (inet_sk(sk)->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;
  
  	/* Reset and regenerate socket error */
  	spin_lock_bh(&sk->sk_error_queue.lock);
  	sk->sk_err = 0;
  	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
  		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
  		spin_unlock_bh(&sk->sk_error_queue.lock);
  		sk->sk_error_report(sk);
  	} else {
  		spin_unlock_bh(&sk->sk_error_queue.lock);
  	}
  
  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 sockaddr_in6 *sin;
  	struct ip6_mtuinfo mtu_info;
  	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_iovec(skb, 0, msg->msg_iov, copied);
  	if (err)
  		goto out_free_skb;
  
  	sock_recv_timestamp(msg, sk, skb);
  
  	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
  
  	sin = (struct sockaddr_in6 *)msg->msg_name;
  	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;
  }
  
  
  int ip6_datagram_recv_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.rxinfo) {
  		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_PKTINFO, sizeof(src_info), &src_info);
  	}
  
  	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);
  		}
  	}
  	return 0;
  }
  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 (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
  		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))
  					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:
  			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
  				       cmsg->cmsg_type);
  			err = -EINVAL;
  			goto exit_f;
  		}
  	}
  
  exit_f:
  	return err;
  }
  EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
  