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if_faith.c revision 1.62 
      1 /*	$NetBSD: if_faith.c,v 1.62 2021/06/16 00:21:19 riastradh Exp $	*/
      2 /*	$KAME: if_faith.c,v 1.21 2001/02/20 07:59:26 itojun Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 1982, 1986, 1993
      6  *	The Regents of the University of California.  All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the University nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 /*
     33  * derived from
     34  *	@(#)if_loop.c	8.1 (Berkeley) 6/10/93
     35  * Id: if_loop.c,v 1.22 1996/06/19 16:24:10 wollman Exp
     36  */
     37 
     38 /*
     39  * IPv6-to-IPv4 TCP relay capturing interface
     40  */
     41 
     42 #include <sys/cdefs.h>
     43 __KERNEL_RCSID(0, "$NetBSD: if_faith.c,v 1.62 2021/06/16 00:21:19 riastradh Exp $");
     44 
     45 #ifdef _KERNEL_OPT
     46 #include "opt_inet.h"
     47 #endif
     48 
     49 #include <sys/param.h>
     50 #include <sys/systm.h>
     51 #include <sys/kernel.h>
     52 #include <sys/mbuf.h>
     53 #include <sys/socket.h>
     54 #include <sys/errno.h>
     55 #include <sys/ioctl.h>
     56 #include <sys/time.h>
     57 #include <sys/queue.h>
     58 #include <sys/device.h>
     59 #include <sys/module.h>
     60 #include <sys/atomic.h>
     61 
     62 #include <sys/cpu.h>
     63 
     64 #include <net/if.h>
     65 #include <net/if_types.h>
     66 #include <net/netisr.h>
     67 #include <net/route.h>
     68 #include <net/bpf.h>
     69 #include <net/if_faith.h>
     70 
     71 #ifdef	INET
     72 #include <netinet/in.h>
     73 #include <netinet/in_systm.h>
     74 #include <netinet/in_var.h>
     75 #include <netinet/ip.h>
     76 #endif
     77 
     78 #ifdef INET6
     79 #ifndef INET
     80 #include <netinet/in.h>
     81 #endif
     82 #include <netinet6/in6_var.h>
     83 #include <netinet/ip6.h>
     84 #include <netinet6/ip6_var.h>
     85 #endif
     86 
     87 #include "ioconf.h"
     88 
     89 static int	faithioctl(struct ifnet *, u_long, void *);
     90 static int	faithoutput(struct ifnet *, struct mbuf *,
     91 		            const struct sockaddr *, const struct rtentry *);
     92 static void	faithrtrequest(int, struct rtentry *,
     93 		               const struct rt_addrinfo *);
     94 
     95 static int	faith_clone_create(struct if_clone *, int);
     96 static int	faith_clone_destroy(struct ifnet *);
     97 
     98 static struct if_clone faith_cloner =
     99     IF_CLONE_INITIALIZER("faith", faith_clone_create, faith_clone_destroy);
    100 
    101 #define	FAITHMTU	1500
    102 
    103 static u_int faith_count;
    104 
    105 /* ARGSUSED */
    106 void
    107 faithattach(int count)
    108 {
    109 
    110 	/*
    111 	 * Nothing to do here, initialization is handled by the
    112 	 * module initialization code in faithinit() below).
    113 	 */
    114 }
    115 
    116 static void
    117 faithinit(void)
    118 {
    119 	if_clone_attach(&faith_cloner);
    120 }
    121 
    122 static int
    123 faithdetach(void)
    124 {
    125 	int error = 0;
    126 
    127 	if (faith_count != 0)
    128 		error = EBUSY;
    129 
    130 	if (error == 0)
    131 		if_clone_detach(&faith_cloner);
    132 
    133 	return error;
    134 }
    135 
    136 static int
    137 faith_clone_create(struct if_clone *ifc, int unit)
    138 {
    139 	struct ifnet *ifp;
    140 
    141 	ifp = if_alloc(IFT_FAITH);
    142 
    143 	if_initname(ifp, ifc->ifc_name, unit);
    144 
    145 	ifp->if_mtu = FAITHMTU;
    146 	/* Change to BROADCAST experimentaly to announce its prefix. */
    147 	ifp->if_flags = /* IFF_LOOPBACK */ IFF_BROADCAST | IFF_MULTICAST;
    148 	ifp->if_ioctl = faithioctl;
    149 	ifp->if_output = faithoutput;
    150 	ifp->if_type = IFT_FAITH;
    151 	ifp->if_hdrlen = 0;
    152 	ifp->if_addrlen = 0;
    153 	ifp->if_dlt = DLT_NULL;
    154 	if_attach(ifp);
    155 	if_alloc_sadl(ifp);
    156 	bpf_attach(ifp, DLT_NULL, sizeof(u_int));
    157 	atomic_inc_uint(&faith_count);
    158 	return (0);
    159 }
    160 
    161 int
    162 faith_clone_destroy(struct ifnet *ifp)
    163 {
    164 
    165 	bpf_detach(ifp);
    166 	if_detach(ifp);
    167 	if_free(ifp);
    168 
    169 	atomic_dec_uint(&faith_count);
    170 	return (0);
    171 }
    172 
    173 static int
    174 faithoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
    175     const struct rtentry *rt)
    176 {
    177 	pktqueue_t *pktq;
    178 	size_t pktlen;
    179 	int s, error;
    180 	uint32_t af;
    181 
    182 	if ((m->m_flags & M_PKTHDR) == 0)
    183 		panic("faithoutput no HDR");
    184 	af = dst->sa_family;
    185 	/* BPF write needs to be handled specially */
    186 	if (af == AF_UNSPEC) {
    187 		af = *(mtod(m, int *));
    188 		m_adj(m, sizeof(int));
    189 	}
    190 
    191 	bpf_mtap_af(ifp, af, m, BPF_D_OUT);
    192 
    193 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
    194 		m_freem(m);
    195 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
    196 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
    197 	}
    198 	pktlen = m->m_pkthdr.len;
    199 	if_statadd2(ifp, if_opackets, 1, if_obytes, pktlen);
    200 	switch (af) {
    201 #ifdef INET
    202 	case AF_INET:
    203 		pktq = ip_pktq;
    204 		break;
    205 #endif
    206 #ifdef INET6
    207 	case AF_INET6:
    208 		pktq = ip6_pktq;
    209 		break;
    210 #endif
    211 	default:
    212 		m_freem(m);
    213 		return EAFNOSUPPORT;
    214 	}
    215 
    216 	/* XXX do we need more sanity checks? */
    217 	KASSERT(pktq != NULL);
    218 	m_set_rcvif(m, ifp);
    219 
    220 	s = splnet();
    221 	if (__predict_true(pktq_enqueue(pktq, m, 0))) {
    222 		if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen);
    223 		error = 0;
    224 	} else {
    225 		m_freem(m);
    226 		error = ENOBUFS;
    227 	}
    228 	splx(s);
    229 
    230 	return error;
    231 }
    232 
    233 /* ARGSUSED */
    234 static void
    235 faithrtrequest(int cmd, struct rtentry *rt,
    236     const struct rt_addrinfo *info)
    237 {
    238 	if (rt)
    239 		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
    240 }
    241 
    242 /*
    243  * Process an ioctl request.
    244  */
    245 /* ARGSUSED */
    246 static int
    247 faithioctl(struct ifnet *ifp, u_long cmd, void *data)
    248 {
    249 	struct ifaddr *ifa;
    250 	struct ifreq *ifr = (struct ifreq *)data;
    251 	int error = 0;
    252 
    253 	switch (cmd) {
    254 
    255 	case SIOCINITIFADDR:
    256 		ifa = (struct ifaddr *)data;
    257 		ifa->ifa_rtrequest = faithrtrequest;
    258 		ifp->if_flags |= IFF_UP | IFF_RUNNING;
    259 		/*
    260 		 * Everything else is done at a higher level.
    261 		 */
    262 		break;
    263 
    264 	case SIOCADDMULTI:
    265 	case SIOCDELMULTI:
    266 		if (ifr == 0) {
    267 			error = EAFNOSUPPORT;		/* XXX */
    268 			break;
    269 		}
    270 		switch (ifr->ifr_addr.sa_family) {
    271 #ifdef INET
    272 		case AF_INET:
    273 			break;
    274 #endif
    275 #ifdef INET6
    276 		case AF_INET6:
    277 			break;
    278 #endif
    279 
    280 		default:
    281 			error = EAFNOSUPPORT;
    282 			break;
    283 		}
    284 		break;
    285 
    286 	default:
    287 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
    288 			error = 0;
    289 		break;
    290 	}
    291 	return (error);
    292 }
    293 
    294 #ifdef INET6
    295 /*
    296  * XXX could be slow
    297  * XXX could be layer violation to call sys/net from sys/netinet6
    298  */
    299 int
    300 faithprefix(struct in6_addr *in6)
    301 {
    302 	struct rtentry *rt;
    303 	struct sockaddr_in6 sin6;
    304 	int ret;
    305 
    306 	if (ip6_keepfaith == 0)
    307 		return 0;
    308 
    309 	memset(&sin6, 0, sizeof(sin6));
    310 	sin6.sin6_family = AF_INET6;
    311 	sin6.sin6_len = sizeof(struct sockaddr_in6);
    312 	sin6.sin6_addr = *in6;
    313 	rt = rtalloc1((struct sockaddr *)&sin6, 0);
    314 	if (rt && rt->rt_ifp && rt->rt_ifp->if_type == IFT_FAITH &&
    315 	    (rt->rt_ifp->if_flags & IFF_UP) != 0)
    316 		ret = 1;
    317 	else
    318 		ret = 0;
    319 	if (rt)
    320 		rt_unref(rt);
    321 	return ret;
    322 }
    323 #endif
    324 
    325 /*
    326  * Module infrastructure
    327  */
    328 #include "if_module.h"
    329 
    330 IF_MODULE(MODULE_CLASS_DRIVER, faith, NULL)
    331