text: /*-
   * Copyright (c) 2009-2010 Ana Kukec <anchie@FreeBSD.org>
   * 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.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #include <sys/param.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/mbuf.h>
  #include <sys/module.h>
  #include <sys/priv.h>
  #include <sys/protosw.h>
  #include <sys/sdt.h>
  #include <sys/systm.h>
  #include <sys/socket.h>
  #include <sys/sockstate.h>
  #include <sys/sockbuf.h>
  #include <sys/socketvar.h>
  #include <sys/types.h>
  
  #include <net/route.h>
  #include <net/if.h>
  #include <net/if_var.h>
  #include <net/vnet.h>
  
  #include <netinet/in.h>
  #include <netinet/in_kdtrace.h>
  #include <netinet/ip_var.h>
  #include <netinet/ip6.h>
  #include <netinet/icmp6.h>
  
  #include <netinet6/in6_var.h>
  #include <netinet6/nd6.h>
  #include <netinet6/scope6_var.h>
  #include <netinet6/send.h>
  
  static MALLOC_DEFINE(M_SEND, "send", "Secure Neighbour Discovery");
  
  /*
   * The socket used to communicate with the SeND daemon.
   */
  static VNET_DEFINE(struct socket *, send_so);
  #define	V_send_so	VNET(send_so)
  
  u_long	send_sendspace	= 8 * (1024 + sizeof(struct sockaddr_send));
  u_long	send_recvspace	= 9216;
  
  struct mtx	send_mtx;
  #define SEND_LOCK_INIT()	mtx_init(&send_mtx, "send_mtx", NULL, MTX_DEF)
  #define SEND_LOCK()		mtx_lock(&send_mtx)
  #define SEND_UNLOCK()		mtx_unlock(&send_mtx)
  #define SEND_LOCK_DESTROY()     mtx_destroy(&send_mtx)
  
  static int
  send_attach(struct socket *so, int proto, struct thread *td)
  {
  	int error;
  
  	SEND_LOCK();
  	if (V_send_so != NULL) {
  		SEND_UNLOCK();
  		return (EEXIST);
  	}
  
  	error = priv_check(td, PRIV_NETINET_RAW);
  	if (error) {
  		SEND_UNLOCK();
  		return(error);
  	}
  
  	if (proto != IPPROTO_SEND) {
  		SEND_UNLOCK();
  		return (EPROTONOSUPPORT);
  	}
  	error = soreserve(so, send_sendspace, send_recvspace);
  	if (error) {
  		SEND_UNLOCK();
  		return(error);
  	}
  
  	V_send_so = so;
  	SEND_UNLOCK();
  
  	return (0);
  }
  
  static int
  send_output(struct mbuf *m, struct ifnet *ifp, int direction)
  {
  	struct ip6_hdr *ip6;
  	struct sockaddr_in6 dst;
  	struct icmp6_hdr *icmp6;
  	int icmp6len;
  
  	/*
  	 * Receive incoming (SeND-protected) or outgoing traffic
  	 * (SeND-validated) from the SeND user space application.
  	 */
  
  	switch (direction) {
  	case SND_IN:
  		if (m->m_len < (sizeof(struct ip6_hdr) +
  		    sizeof(struct icmp6_hdr))) {
  			m = m_pullup(m, sizeof(struct ip6_hdr) +
  			    sizeof(struct icmp6_hdr));
  			if (!m)
  				return (ENOBUFS);
  		}
  
  		/* Before passing off the mbuf record the proper interface. */
  		m->m_pkthdr.rcvif = ifp;
  
  		if (m->m_flags & M_PKTHDR)
  			icmp6len = m->m_pkthdr.len - sizeof(struct ip6_hdr);
  		else
  			panic("Doh! not the first mbuf.");
  
  		ip6 = mtod(m, struct ip6_hdr *);
  		icmp6 = (struct icmp6_hdr *)(ip6 + 1);
  
  		/*
  		 * Output the packet as icmp6.c:icpm6_input() would do.
  		 * The mbuf is always consumed, so we do not have to
  		 * care about that.
  		 */
  		switch (icmp6->icmp6_type) {
  		case ND_NEIGHBOR_SOLICIT:
  			nd6_ns_input(m, sizeof(struct ip6_hdr), icmp6len);
  			break;
  		case ND_NEIGHBOR_ADVERT:
  			nd6_na_input(m, sizeof(struct ip6_hdr), icmp6len);
  			break;
  		case ND_REDIRECT:
  			icmp6_redirect_input(m, sizeof(struct ip6_hdr));
  			break;
  		case ND_ROUTER_SOLICIT:
  			nd6_rs_input(m, sizeof(struct ip6_hdr), icmp6len);
  			break;
  		case ND_ROUTER_ADVERT:
  			nd6_ra_input(m, sizeof(struct ip6_hdr), icmp6len);
  			break;
  		default:
  			m_freem(m);
  			return (ENOSYS);
  		}
  		return (0);
  
  	case SND_OUT:
  		if (m->m_len < sizeof(struct ip6_hdr)) {
  			m = m_pullup(m, sizeof(struct ip6_hdr));
  			if (!m)
  				return (ENOBUFS);
  		}
  		ip6 = mtod(m, struct ip6_hdr *);
  		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
  			m->m_flags |= M_MCAST;
  
  		bzero(&dst, sizeof(dst));
  		dst.sin6_family = AF_INET6;
  		dst.sin6_len = sizeof(dst);
  		dst.sin6_addr = ip6->ip6_dst;
  
  		m_clrprotoflags(m);	/* Avoid confusing lower layers. */
  
  		IP_PROBE(send, NULL, NULL, ip6, ifp, NULL, ip6);
  
  		/*
  		 * Output the packet as nd6.c:nd6_output_lle() would do.
  		 * The mbuf is always consumed, so we do not have to care
  		 * about that.
  		 * XXX-BZ as we added data, what about fragmenting,
  		 * if now needed?
  		 */
  		int error;
  		error = ((*ifp->if_output)(ifp, m, (struct sockaddr *)&dst,
  		    NULL));
  		if (error)
  			error = ENOENT;
  		return (error);
  
  	default:
  		panic("%s: direction %d neither SND_IN nor SND_OUT.",
  		     __func__, direction);
  	}
  }
  
  /*
   * Receive a SeND message from user space to be either send out by the kernel
   * or, with SeND ICMPv6 options removed, to be further processed by the icmp6
   * input path.
   */
  static int
  send_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
      struct mbuf *control, struct thread *td)
  {
  	struct sockaddr_send *sendsrc;
  	struct ifnet *ifp;
  	int error;
  
  	KASSERT(V_send_so == so, ("%s: socket %p not send socket %p",
  		__func__, so, V_send_so));
  
  	sendsrc = (struct sockaddr_send *)nam;
  	ifp = ifnet_byindex_ref(sendsrc->send_ifidx);
  	if (ifp == NULL) {
  		error = ENETUNREACH;
  		goto err;
  	}
  
  	error = send_output(m, ifp, sendsrc->send_direction);
  	if_rele(ifp);
  	m = NULL;
  
  err:
  	if (m != NULL)
  		m_freem(m);
  	return (error);
  }
  
  static void
  send_close(struct socket *so)
  {
  
  	SEND_LOCK();
  	if (V_send_so)
  		V_send_so = NULL;
  	SEND_UNLOCK();
  }
  
  /*
   * Send a SeND message to user space, that was either received and has to be
   * validated or was about to be send out and has to be handled by the SEND
   * daemon adding SeND ICMPv6 options.
   */
  static int
  send_input(struct mbuf *m, struct ifnet *ifp, int direction, int msglen __unused)
  {
  	struct ip6_hdr *ip6;
  	struct sockaddr_send sendsrc;
  
  	SEND_LOCK();
  	if (V_send_so == NULL) {
  		SEND_UNLOCK();
  		return (-1);
  	}
  
  	/*
  	 * Make sure to clear any possible internally embedded scope before
  	 * passing the packet to user space for SeND cryptographic signature
  	 * validation to succeed.
  	 */
  	ip6 = mtod(m, struct ip6_hdr *);
  	in6_clearscope(&ip6->ip6_src);
  	in6_clearscope(&ip6->ip6_dst);
  
  	bzero(&sendsrc, sizeof(sendsrc));
  	sendsrc.send_len = sizeof(sendsrc);
  	sendsrc.send_family = AF_INET6;
  	sendsrc.send_direction = direction;
  	sendsrc.send_ifidx = ifp->if_index;
  
  	/*
  	 * Send incoming or outgoing traffic to user space either to be
  	 * protected (outgoing) or validated (incoming) according to rfc3971.
  	 */
  	SOCKBUF_LOCK(&V_send_so->so_rcv);
  	if (sbappendaddr_locked(&V_send_so->so_rcv,
  	    (struct sockaddr *)&sendsrc, m, NULL) == 0) {
  		SOCKBUF_UNLOCK(&V_send_so->so_rcv);
  		/* XXX stats. */
  		m_freem(m);
  	} else {
  		sorwakeup_locked(V_send_so);
  	}
  
  	SEND_UNLOCK();
  	return (0);
  }
  
  struct pr_usrreqs send_usrreqs = {
  	.pru_attach =		send_attach,
  	.pru_send =		send_send,
  	.pru_detach =		send_close
  };
  struct protosw send_protosw = {
  	.pr_type =		SOCK_RAW,
  	.pr_flags =		PR_ATOMIC|PR_ADDR,
  	.pr_protocol =		IPPROTO_SEND,
  	.pr_usrreqs =		&send_usrreqs
  };
  
  static int
  send_modevent(module_t mod, int type, void *unused)
  {
  #ifdef __notyet__
  	VNET_ITERATOR_DECL(vnet_iter);
  #endif
  	int error;
  
  	switch (type) {
  	case MOD_LOAD:
  		SEND_LOCK_INIT();
  
  		error = pf_proto_register(PF_INET6, &send_protosw);
  		if (error != 0) {
  			printf("%s:%d: MOD_LOAD pf_proto_register(): %d\n",
  			   __func__, __LINE__, error);
  			SEND_LOCK_DESTROY();
  			break;
  		}
  		send_sendso_input_hook = send_input;
  		break;
  	case MOD_UNLOAD:
  		/* Do not allow unloading w/o locking. */
  		return (EBUSY);
  #ifdef __notyet__
  		VNET_LIST_RLOCK_NOSLEEP();
  		SEND_LOCK();
  		VNET_FOREACH(vnet_iter) {
  			CURVNET_SET(vnet_iter);
  			if (V_send_so != NULL) {
  				CURVNET_RESTORE();
  				SEND_UNLOCK();
  				VNET_LIST_RUNLOCK_NOSLEEP();
  				return (EBUSY);
  			}
  			CURVNET_RESTORE();
  		}
  		SEND_UNLOCK();
  		VNET_LIST_RUNLOCK_NOSLEEP();
  		error = pf_proto_unregister(PF_INET6, IPPROTO_SEND, SOCK_RAW);
  		if (error == 0)
  			SEND_LOCK_DESTROY();
  		send_sendso_input_hook = NULL;
  		break;
  #endif
  	default:
  		error = 0;
  		break;
  	}
  
  	return (error);
  }
  
  static moduledata_t sendmod = {
  	"send",
  	send_modevent,
  	0
  };
  
  DECLARE_MODULE(send, sendmod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
  