text: /*-
   * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the project nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  /*-
   * Copyright (c) 1982, 1986, 1988, 1993
   *	The Regents of the University of California.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	@(#)raw_ip.c	8.2 (Berkeley) 1/4/94
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: releng/11.0/sys/netinet6/raw_ip6.c 298075 2016-04-15 17:30:33Z pfg $");
  
  #include "opt_ipsec.h"
  #include "opt_inet6.h"
  
  #include <sys/param.h>
  #include <sys/errno.h>
  #include <sys/jail.h>
  #include <sys/kernel.h>
  #include <sys/lock.h>
  #include <sys/malloc.h>
  #include <sys/mbuf.h>
  #include <sys/priv.h>
  #include <sys/proc.h>
  #include <sys/protosw.h>
  #include <sys/signalvar.h>
  #include <sys/socket.h>
  #include <sys/socketvar.h>
  #include <sys/sx.h>
  #include <sys/syslog.h>
  
  #include <net/if.h>
  #include <net/if_var.h>
  #include <net/if_types.h>
  #include <net/route.h>
  #include <net/vnet.h>
  
  #include <netinet/in.h>
  #include <netinet/in_var.h>
  #include <netinet/in_systm.h>
  #include <netinet/in_pcb.h>
  
  #include <netinet/icmp6.h>
  #include <netinet/ip6.h>
  #include <netinet/ip_var.h>
  #include <netinet6/ip6protosw.h>
  #include <netinet6/ip6_mroute.h>
  #include <netinet6/in6_pcb.h>
  #include <netinet6/ip6_var.h>
  #include <netinet6/nd6.h>
  #include <netinet6/raw_ip6.h>
  #include <netinet6/scope6_var.h>
  #include <netinet6/send.h>
  
  #ifdef IPSEC
  #include <netipsec/ipsec.h>
  #include <netipsec/ipsec6.h>
  #endif /* IPSEC */
  
  #include <machine/stdarg.h>
  
  #define	satosin6(sa)	((struct sockaddr_in6 *)(sa))
  #define	ifatoia6(ifa)	((struct in6_ifaddr *)(ifa))
  
  /*
   * Raw interface to IP6 protocol.
   */
  
  VNET_DECLARE(struct inpcbhead, ripcb);
  VNET_DECLARE(struct inpcbinfo, ripcbinfo);
  #define	V_ripcb				VNET(ripcb)
  #define	V_ripcbinfo			VNET(ripcbinfo)
  
  extern u_long	rip_sendspace;
  extern u_long	rip_recvspace;
  
  VNET_PCPUSTAT_DEFINE(struct rip6stat, rip6stat);
  VNET_PCPUSTAT_SYSINIT(rip6stat);
  
  #ifdef VIMAGE
  VNET_PCPUSTAT_SYSUNINIT(rip6stat);
  #endif /* VIMAGE */
  
  /*
   * Hooks for multicast routing. They all default to NULL, so leave them not
   * initialized and rely on BSS being set to 0.
   */
  
  /*
   * The socket used to communicate with the multicast routing daemon.
   */
  VNET_DEFINE(struct socket *, ip6_mrouter);
  
  /*
   * The various mrouter functions.
   */
  int (*ip6_mrouter_set)(struct socket *, struct sockopt *);
  int (*ip6_mrouter_get)(struct socket *, struct sockopt *);
  int (*ip6_mrouter_done)(void);
  int (*ip6_mforward)(struct ip6_hdr *, struct ifnet *, struct mbuf *);
  int (*mrt6_ioctl)(u_long, caddr_t);
  
  /*
   * Setup generic address and protocol structures for raw_input routine, then
   * pass them along with mbuf chain.
   */
  int
  rip6_input(struct mbuf **mp, int *offp, int proto)
  {
  	struct ifnet *ifp;
  	struct mbuf *m = *mp;
  	register struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  	register struct inpcb *in6p;
  	struct inpcb *last = NULL;
  	struct mbuf *opts = NULL;
  	struct sockaddr_in6 fromsa;
  
  	RIP6STAT_INC(rip6s_ipackets);
  
  	init_sin6(&fromsa, m); /* general init */
  
  	ifp = m->m_pkthdr.rcvif;
  
  	INP_INFO_RLOCK(&V_ripcbinfo);
  	LIST_FOREACH(in6p, &V_ripcb, inp_list) {
  		/* XXX inp locking */
  		if ((in6p->inp_vflag & INP_IPV6) == 0)
  			continue;
  		if (in6p->inp_ip_p &&
  		    in6p->inp_ip_p != proto)
  			continue;
  		if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr) &&
  		    !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst))
  			continue;
  		if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr) &&
  		    !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src))
  			continue;
  		if (jailed_without_vnet(in6p->inp_cred)) {
  			/*
  			 * Allow raw socket in jail to receive multicast;
  			 * assume process had PRIV_NETINET_RAW at attach,
  			 * and fall through into normal filter path if so.
  			 */
  			if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
  			    prison_check_ip6(in6p->inp_cred,
  			    &ip6->ip6_dst) != 0)
  				continue;
  		}
  		INP_RLOCK(in6p);
  		if (in6p->in6p_cksum != -1) {
  			RIP6STAT_INC(rip6s_isum);
  			if (in6_cksum(m, proto, *offp,
  			    m->m_pkthdr.len - *offp)) {
  				INP_RUNLOCK(in6p);
  				RIP6STAT_INC(rip6s_badsum);
  				continue;
  			}
  		}
  		/*
  		 * If this raw socket has multicast state, and we
  		 * have received a multicast, check if this socket
  		 * should receive it, as multicast filtering is now
  		 * the responsibility of the transport layer.
  		 */
  		if (in6p->in6p_moptions &&
  		    IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  			/*
  			 * If the incoming datagram is for MLD, allow it
  			 * through unconditionally to the raw socket.
  			 *
  			 * Use the M_RTALERT_MLD flag to check for MLD
  			 * traffic without having to inspect the mbuf chain
  			 * more deeply, as all MLDv1/v2 host messages MUST
  			 * contain the Router Alert option.
  			 *
  			 * In the case of MLDv1, we may not have explicitly
  			 * joined the group, and may have set IFF_ALLMULTI
  			 * on the interface. im6o_mc_filter() may discard
  			 * control traffic we actually need to see.
  			 *
  			 * Userland multicast routing daemons should continue
  			 * filter the control traffic appropriately.
  			 */
  			int blocked;
  
  			blocked = MCAST_PASS;
  			if ((m->m_flags & M_RTALERT_MLD) == 0) {
  				struct sockaddr_in6 mcaddr;
  
  				bzero(&mcaddr, sizeof(struct sockaddr_in6));
  				mcaddr.sin6_len = sizeof(struct sockaddr_in6);
  				mcaddr.sin6_family = AF_INET6;
  				mcaddr.sin6_addr = ip6->ip6_dst;
  
  				blocked = im6o_mc_filter(in6p->in6p_moptions,
  				    ifp,
  				    (struct sockaddr *)&mcaddr,
  				    (struct sockaddr *)&fromsa);
  			}
  			if (blocked != MCAST_PASS) {
  				IP6STAT_INC(ip6s_notmember);
  				INP_RUNLOCK(in6p);
  				continue;
  			}
  		}
  		if (last != NULL) {
  			struct mbuf *n = m_copy(m, 0, (int)M_COPYALL);
  
  #ifdef IPSEC
  			/*
  			 * Check AH/ESP integrity.
  			 */
  			if (n && ipsec6_in_reject(n, last)) {
  				m_freem(n);
  				/* Do not inject data into pcb. */
  			} else
  #endif /* IPSEC */
  			if (n) {
  				if (last->inp_flags & INP_CONTROLOPTS ||
  				    last->inp_socket->so_options & SO_TIMESTAMP)
  					ip6_savecontrol(last, n, &opts);
  				/* strip intermediate headers */
  				m_adj(n, *offp);
  				if (sbappendaddr(&last->inp_socket->so_rcv,
  						(struct sockaddr *)&fromsa,
  						 n, opts) == 0) {
  					m_freem(n);
  					if (opts)
  						m_freem(opts);
  					RIP6STAT_INC(rip6s_fullsock);
  				} else
  					sorwakeup(last->inp_socket);
  				opts = NULL;
  			}
  			INP_RUNLOCK(last);
  		}
  		last = in6p;
  	}
  	INP_INFO_RUNLOCK(&V_ripcbinfo);
  #ifdef IPSEC
  	/*
  	 * Check AH/ESP integrity.
  	 */
  	if ((last != NULL) && ipsec6_in_reject(m, last)) {
  		m_freem(m);
  		IP6STAT_DEC(ip6s_delivered);
  		/* Do not inject data into pcb. */
  		INP_RUNLOCK(last);
  	} else
  #endif /* IPSEC */
  	if (last != NULL) {
  		if (last->inp_flags & INP_CONTROLOPTS ||
  		    last->inp_socket->so_options & SO_TIMESTAMP)
  			ip6_savecontrol(last, m, &opts);
  		/* Strip intermediate headers. */
  		m_adj(m, *offp);
  		if (sbappendaddr(&last->inp_socket->so_rcv,
  		    (struct sockaddr *)&fromsa, m, opts) == 0) {
  			m_freem(m);
  			if (opts)
  				m_freem(opts);
  			RIP6STAT_INC(rip6s_fullsock);
  		} else
  			sorwakeup(last->inp_socket);
  		INP_RUNLOCK(last);
  	} else {
  		RIP6STAT_INC(rip6s_nosock);
  		if (m->m_flags & M_MCAST)
  			RIP6STAT_INC(rip6s_nosockmcast);
  		if (proto == IPPROTO_NONE)
  			m_freem(m);
  		else {
  			char *prvnxtp = ip6_get_prevhdr(m, *offp); /* XXX */
  			icmp6_error(m, ICMP6_PARAM_PROB,
  			    ICMP6_PARAMPROB_NEXTHEADER,
  			    prvnxtp - mtod(m, char *));
  		}
  		IP6STAT_DEC(ip6s_delivered);
  	}
  	return (IPPROTO_DONE);
  }
  
  void
  rip6_ctlinput(int cmd, struct sockaddr *sa, void *d)
  {
  	struct ip6_hdr *ip6;
  	struct mbuf *m;
  	int off = 0;
  	struct ip6ctlparam *ip6cp = NULL;
  	const struct sockaddr_in6 *sa6_src = NULL;
  	void *cmdarg;
  	struct inpcb *(*notify)(struct inpcb *, int) = in6_rtchange;
  
  	if (sa->sa_family != AF_INET6 ||
  	    sa->sa_len != sizeof(struct sockaddr_in6))
  		return;
  
  	if ((unsigned)cmd >= PRC_NCMDS)
  		return;
  	if (PRC_IS_REDIRECT(cmd))
  		notify = in6_rtchange, d = NULL;
  	else if (cmd == PRC_HOSTDEAD)
  		d = NULL;
  	else if (inet6ctlerrmap[cmd] == 0)
  		return;
  
  	/*
  	 * If the parameter is from icmp6, decode it.
  	 */
  	if (d != NULL) {
  		ip6cp = (struct ip6ctlparam *)d;
  		m = ip6cp->ip6c_m;
  		ip6 = ip6cp->ip6c_ip6;
  		off = ip6cp->ip6c_off;
  		cmdarg = ip6cp->ip6c_cmdarg;
  		sa6_src = ip6cp->ip6c_src;
  	} else {
  		m = NULL;
  		ip6 = NULL;
  		cmdarg = NULL;
  		sa6_src = &sa6_any;
  	}
  
  	(void) in6_pcbnotify(&V_ripcbinfo, sa, 0,
  	    (const struct sockaddr *)sa6_src, 0, cmd, cmdarg, notify);
  }
  
  /*
   * Generate IPv6 header and pass packet to ip6_output.  Tack on options user
   * may have setup with control call.
   */
  int
  rip6_output(struct mbuf *m, struct socket *so, ...)
  {
  	struct mbuf *control;
  	struct m_tag *mtag;
  	struct sockaddr_in6 *dstsock;
  	struct in6_addr *dst;
  	struct ip6_hdr *ip6;
  	struct inpcb *in6p;
  	u_int	plen = m->m_pkthdr.len;
  	int error = 0;
  	struct ip6_pktopts opt, *optp;
  	struct ifnet *oifp = NULL;
  	int type = 0, code = 0;		/* for ICMPv6 output statistics only */
  	int scope_ambiguous = 0;
  	int use_defzone = 0;
  	int hlim = 0;
  	struct in6_addr in6a;
  	va_list ap;
  
  	va_start(ap, so);
  	dstsock = va_arg(ap, struct sockaddr_in6 *);
  	control = va_arg(ap, struct mbuf *);
  	va_end(ap);
  
  	in6p = sotoinpcb(so);
  	INP_WLOCK(in6p);
  
  	dst = &dstsock->sin6_addr;
  	if (control != NULL) {
  		if ((error = ip6_setpktopts(control, &opt,
  		    in6p->in6p_outputopts, so->so_cred,
  		    so->so_proto->pr_protocol)) != 0) {
  			goto bad;
  		}
  		optp = &opt;
  	} else
  		optp = in6p->in6p_outputopts;
  
  	/*
  	 * Check and convert scope zone ID into internal form.
  	 *
  	 * XXX: we may still need to determine the zone later.
  	 */
  	if (!(so->so_state & SS_ISCONNECTED)) {
  		if (!optp || !optp->ip6po_pktinfo ||
  		    !optp->ip6po_pktinfo->ipi6_ifindex)
  			use_defzone = V_ip6_use_defzone;
  		if (dstsock->sin6_scope_id == 0 && !use_defzone)
  			scope_ambiguous = 1;
  		if ((error = sa6_embedscope(dstsock, use_defzone)) != 0)
  			goto bad;
  	}
  
  	/*
  	 * For an ICMPv6 packet, we should know its type and code to update
  	 * statistics.
  	 */
  	if (so->so_proto->pr_protocol == IPPROTO_ICMPV6) {
  		struct icmp6_hdr *icmp6;
  		if (m->m_len < sizeof(struct icmp6_hdr) &&
  		    (m = m_pullup(m, sizeof(struct icmp6_hdr))) == NULL) {
  			error = ENOBUFS;
  			goto bad;
  		}
  		icmp6 = mtod(m, struct icmp6_hdr *);
  		type = icmp6->icmp6_type;
  		code = icmp6->icmp6_code;
  	}
  
  	M_PREPEND(m, sizeof(*ip6), M_NOWAIT);
  	if (m == NULL) {
  		error = ENOBUFS;
  		goto bad;
  	}
  	ip6 = mtod(m, struct ip6_hdr *);
  
  	/*
  	 * Source address selection.
  	 */
  	error = in6_selectsrc_socket(dstsock, optp, in6p, so->so_cred,
  	    scope_ambiguous, &in6a, &hlim);
  
  	if (error)
  		goto bad;
  	error = prison_check_ip6(in6p->inp_cred, &in6a);
  	if (error != 0)
  		goto bad;
  	ip6->ip6_src = in6a;
  
  	ip6->ip6_dst = dstsock->sin6_addr;
  
  	/*
  	 * Fill in the rest of the IPv6 header fields.
  	 */
  	ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
  	    (in6p->inp_flow & IPV6_FLOWINFO_MASK);
  	ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
  	    (IPV6_VERSION & IPV6_VERSION_MASK);
  
  	/*
  	 * ip6_plen will be filled in ip6_output, so not fill it here.
  	 */
  	ip6->ip6_nxt = in6p->inp_ip_p;
  	ip6->ip6_hlim = hlim;
  
  	if (so->so_proto->pr_protocol == IPPROTO_ICMPV6 ||
  	    in6p->in6p_cksum != -1) {
  		struct mbuf *n;
  		int off;
  		u_int16_t *p;
  
  		/* Compute checksum. */
  		if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
  			off = offsetof(struct icmp6_hdr, icmp6_cksum);
  		else
  			off = in6p->in6p_cksum;
  		if (plen < off + 1) {
  			error = EINVAL;
  			goto bad;
  		}
  		off += sizeof(struct ip6_hdr);
  
  		n = m;
  		while (n && n->m_len <= off) {
  			off -= n->m_len;
  			n = n->m_next;
  		}
  		if (!n)
  			goto bad;
  		p = (u_int16_t *)(mtod(n, caddr_t) + off);
  		*p = 0;
  		*p = in6_cksum(m, ip6->ip6_nxt, sizeof(*ip6), plen);
  	}
  
  	/*
  	 * Send RA/RS messages to user land for protection, before sending
  	 * them to rtadvd/rtsol.
  	 */
  	if ((send_sendso_input_hook != NULL) &&
  	    so->so_proto->pr_protocol == IPPROTO_ICMPV6) {
  		switch (type) {
  		case ND_ROUTER_ADVERT:
  		case ND_ROUTER_SOLICIT:
  			mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
  				sizeof(unsigned short), M_NOWAIT);
  			if (mtag == NULL)
  				goto bad;
  			m_tag_prepend(m, mtag);
  		}
  	}
  
  	error = ip6_output(m, optp, NULL, 0, in6p->in6p_moptions, &oifp, in6p);
  	if (so->so_proto->pr_protocol == IPPROTO_ICMPV6) {
  		if (oifp)
  			icmp6_ifoutstat_inc(oifp, type, code);
  		ICMP6STAT_INC(icp6s_outhist[type]);
  	} else
  		RIP6STAT_INC(rip6s_opackets);
  
  	goto freectl;
  
   bad:
  	if (m)
  		m_freem(m);
  
   freectl:
  	if (control != NULL) {
  		ip6_clearpktopts(&opt, -1);
  		m_freem(control);
  	}
  	INP_WUNLOCK(in6p);
  	return (error);
  }
  
  /*
   * Raw IPv6 socket option processing.
   */
  int
  rip6_ctloutput(struct socket *so, struct sockopt *sopt)
  {
  	struct inpcb *inp;
  	int error;
  
  	if (sopt->sopt_level == IPPROTO_ICMPV6)
  		/*
  		 * XXX: is it better to call icmp6_ctloutput() directly
  		 * from protosw?
  		 */
  		return (icmp6_ctloutput(so, sopt));
  	else if (sopt->sopt_level != IPPROTO_IPV6) {
  		if (sopt->sopt_level == SOL_SOCKET &&
  		    sopt->sopt_name == SO_SETFIB) {
  			inp = sotoinpcb(so);
  			INP_WLOCK(inp);
  			inp->inp_inc.inc_fibnum = so->so_fibnum;
  			INP_WUNLOCK(inp);
  			return (0);
  		}
  		return (EINVAL);
  	}
  
  	error = 0;
  
  	switch (sopt->sopt_dir) {
  	case SOPT_GET:
  		switch (sopt->sopt_name) {
  		case MRT6_INIT:
  		case MRT6_DONE:
  		case MRT6_ADD_MIF:
  		case MRT6_DEL_MIF:
  		case MRT6_ADD_MFC:
  		case MRT6_DEL_MFC:
  		case MRT6_PIM:
  			error = ip6_mrouter_get ?  ip6_mrouter_get(so, sopt) :
  			    EOPNOTSUPP;
  			break;
  		case IPV6_CHECKSUM:
  			error = ip6_raw_ctloutput(so, sopt);
  			break;
  		default:
  			error = ip6_ctloutput(so, sopt);
  			break;
  		}
  		break;
  
  	case SOPT_SET:
  		switch (sopt->sopt_name) {
  		case MRT6_INIT:
  		case MRT6_DONE:
  		case MRT6_ADD_MIF:
  		case MRT6_DEL_MIF:
  		case MRT6_ADD_MFC:
  		case MRT6_DEL_MFC:
  		case MRT6_PIM:
  			error = ip6_mrouter_set ?  ip6_mrouter_set(so, sopt) :
  			    EOPNOTSUPP;
  			break;
  		case IPV6_CHECKSUM:
  			error = ip6_raw_ctloutput(so, sopt);
  			break;
  		default:
  			error = ip6_ctloutput(so, sopt);
  			break;
  		}
  		break;
  	}
  
  	return (error);
  }
  
  static int
  rip6_attach(struct socket *so, int proto, struct thread *td)
  {
  	struct inpcb *inp;
  	struct icmp6_filter *filter;
  	int error;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp == NULL, ("rip6_attach: inp != NULL"));
  
  	error = priv_check(td, PRIV_NETINET_RAW);
  	if (error)
  		return (error);
  	error = soreserve(so, rip_sendspace, rip_recvspace);
  	if (error)
  		return (error);
  	filter = malloc(sizeof(struct icmp6_filter), M_PCB, M_NOWAIT);
  	if (filter == NULL)
  		return (ENOMEM);
  	INP_INFO_WLOCK(&V_ripcbinfo);
  	error = in_pcballoc(so, &V_ripcbinfo);
  	if (error) {
  		INP_INFO_WUNLOCK(&V_ripcbinfo);
  		free(filter, M_PCB);
  		return (error);
  	}
  	inp = (struct inpcb *)so->so_pcb;
  	INP_INFO_WUNLOCK(&V_ripcbinfo);
  	inp->inp_vflag |= INP_IPV6;
  	inp->inp_ip_p = (long)proto;
  	inp->in6p_hops = -1;	/* use kernel default */
  	inp->in6p_cksum = -1;
  	inp->in6p_icmp6filt = filter;
  	ICMP6_FILTER_SETPASSALL(inp->in6p_icmp6filt);
  	INP_WUNLOCK(inp);
  	return (0);
  }
  
  static void
  rip6_detach(struct socket *so)
  {
  	struct inpcb *inp;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_detach: inp == NULL"));
  
  	if (so == V_ip6_mrouter && ip6_mrouter_done)
  		ip6_mrouter_done();
  	/* xxx: RSVP */
  	INP_INFO_WLOCK(&V_ripcbinfo);
  	INP_WLOCK(inp);
  	free(inp->in6p_icmp6filt, M_PCB);
  	in_pcbdetach(inp);
  	in_pcbfree(inp);
  	INP_INFO_WUNLOCK(&V_ripcbinfo);
  }
  
  /* XXXRW: This can't ever be called. */
  static void
  rip6_abort(struct socket *so)
  {
  	struct inpcb *inp;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_abort: inp == NULL"));
  
  	soisdisconnected(so);
  }
  
  static void
  rip6_close(struct socket *so)
  {
  	struct inpcb *inp;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_close: inp == NULL"));
  
  	soisdisconnected(so);
  }
  
  static int
  rip6_disconnect(struct socket *so)
  {
  	struct inpcb *inp;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_disconnect: inp == NULL"));
  
  	if ((so->so_state & SS_ISCONNECTED) == 0)
  		return (ENOTCONN);
  	inp->in6p_faddr = in6addr_any;
  	rip6_abort(so);
  	return (0);
  }
  
  static int
  rip6_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
  {
  	struct inpcb *inp;
  	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)nam;
  	struct ifaddr *ifa = NULL;
  	int error = 0;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_bind: inp == NULL"));
  
  	if (nam->sa_len != sizeof(*addr))
  		return (EINVAL);
  	if ((error = prison_check_ip6(td->td_ucred, &addr->sin6_addr)) != 0)
  		return (error);
  	if (TAILQ_EMPTY(&V_ifnet) || addr->sin6_family != AF_INET6)
  		return (EADDRNOTAVAIL);
  	if ((error = sa6_embedscope(addr, V_ip6_use_defzone)) != 0)
  		return (error);
  
  	if (!IN6_IS_ADDR_UNSPECIFIED(&addr->sin6_addr) &&
  	    (ifa = ifa_ifwithaddr((struct sockaddr *)addr)) == NULL)
  		return (EADDRNOTAVAIL);
  	if (ifa != NULL &&
  	    ((struct in6_ifaddr *)ifa)->ia6_flags &
  	    (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY|
  	     IN6_IFF_DETACHED|IN6_IFF_DEPRECATED)) {
  		ifa_free(ifa);
  		return (EADDRNOTAVAIL);
  	}
  	if (ifa != NULL)
  		ifa_free(ifa);
  	INP_INFO_WLOCK(&V_ripcbinfo);
  	INP_WLOCK(inp);
  	inp->in6p_laddr = addr->sin6_addr;
  	INP_WUNLOCK(inp);
  	INP_INFO_WUNLOCK(&V_ripcbinfo);
  	return (0);
  }
  
  static int
  rip6_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
  {
  	struct inpcb *inp;
  	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)nam;
  	struct in6_addr in6a;
  	int error = 0, scope_ambiguous = 0;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_connect: inp == NULL"));
  
  	if (nam->sa_len != sizeof(*addr))
  		return (EINVAL);
  	if (TAILQ_EMPTY(&V_ifnet))
  		return (EADDRNOTAVAIL);
  	if (addr->sin6_family != AF_INET6)
  		return (EAFNOSUPPORT);
  
  	/*
  	 * Application should provide a proper zone ID or the use of default
  	 * zone IDs should be enabled.  Unfortunately, some applications do
  	 * not behave as it should, so we need a workaround.  Even if an
  	 * appropriate ID is not determined, we'll see if we can determine
  	 * the outgoing interface.  If we can, determine the zone ID based on
  	 * the interface below.
  	 */
  	if (addr->sin6_scope_id == 0 && !V_ip6_use_defzone)
  		scope_ambiguous = 1;
  	if ((error = sa6_embedscope(addr, V_ip6_use_defzone)) != 0)
  		return (error);
  
  	INP_INFO_WLOCK(&V_ripcbinfo);
  	INP_WLOCK(inp);
  	/* Source address selection. XXX: need pcblookup? */
  	error = in6_selectsrc_socket(addr, inp->in6p_outputopts,
  	    inp, so->so_cred, scope_ambiguous, &in6a, NULL);
  	if (error) {
  		INP_WUNLOCK(inp);
  		INP_INFO_WUNLOCK(&V_ripcbinfo);
  		return (error);
  	}
  
  	inp->in6p_faddr = addr->sin6_addr;
  	inp->in6p_laddr = in6a;
  	soisconnected(so);
  	INP_WUNLOCK(inp);
  	INP_INFO_WUNLOCK(&V_ripcbinfo);
  	return (0);
  }
  
  static int
  rip6_shutdown(struct socket *so)
  {
  	struct inpcb *inp;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_shutdown: inp == NULL"));
  
  	INP_WLOCK(inp);
  	socantsendmore(so);
  	INP_WUNLOCK(inp);
  	return (0);
  }
  
  static int
  rip6_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
      struct mbuf *control, struct thread *td)
  {
  	struct inpcb *inp;
  	struct sockaddr_in6 tmp;
  	struct sockaddr_in6 *dst;
  	int ret;
  
  	inp = sotoinpcb(so);
  	KASSERT(inp != NULL, ("rip6_send: inp == NULL"));
  
  	/* Always copy sockaddr to avoid overwrites. */
  	/* Unlocked read. */
  	if (so->so_state & SS_ISCONNECTED) {
  		if (nam) {
  			m_freem(m);
  			return (EISCONN);
  		}
  		/* XXX */
  		bzero(&tmp, sizeof(tmp));
  		tmp.sin6_family = AF_INET6;
  		tmp.sin6_len = sizeof(struct sockaddr_in6);
  		INP_RLOCK(inp);
  		bcopy(&inp->in6p_faddr, &tmp.sin6_addr,
  		    sizeof(struct in6_addr));
  		INP_RUNLOCK(inp);
  		dst = &tmp;
  	} else {
  		if (nam == NULL) {
  			m_freem(m);
  			return (ENOTCONN);
  		}
  		if (nam->sa_len != sizeof(struct sockaddr_in6)) {
  			m_freem(m);
  			return (EINVAL);
  		}
  		tmp = *(struct sockaddr_in6 *)nam;
  		dst = &tmp;
  
  		if (dst->sin6_family == AF_UNSPEC) {
  			/*
  			 * XXX: we allow this case for backward
  			 * compatibility to buggy applications that
  			 * rely on old (and wrong) kernel behavior.
  			 */
  			log(LOG_INFO, "rip6 SEND: address family is "
  			    "unspec. Assume AF_INET6\n");
  			dst->sin6_family = AF_INET6;
  		} else if (dst->sin6_family != AF_INET6) {
  			m_freem(m);
  			return(EAFNOSUPPORT);
  		}
  	}
  	ret = rip6_output(m, so, dst, control);
  	return (ret);
  }
  
  struct pr_usrreqs rip6_usrreqs = {
  	.pru_abort =		rip6_abort,
  	.pru_attach =		rip6_attach,
  	.pru_bind =		rip6_bind,
  	.pru_connect =		rip6_connect,
  	.pru_control =		in6_control,
  	.pru_detach =		rip6_detach,
  	.pru_disconnect =	rip6_disconnect,
  	.pru_peeraddr =		in6_getpeeraddr,
  	.pru_send =		rip6_send,
  	.pru_shutdown =		rip6_shutdown,
  	.pru_sockaddr =		in6_getsockaddr,
  	.pru_close =		rip6_close,
  };
  