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      1 /*	$NetBSD: if_faith.c,v 1.64 2024/09/07 06:17:37 andvar 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 1.64 2024/09/07 06:17:37 andvar 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/route.h>
     67 #include <net/bpf.h>
     68 #include <net/if_faith.h>
     69 
     70 #ifdef	INET
     71 #include <netinet/in.h>
     72 #include <netinet/in_systm.h>
     73 #include <netinet/in_var.h>
     74 #include <netinet/ip.h>
     75 #endif
     76 
     77 #ifdef INET6
     78 #ifndef INET
     79 #include <netinet/in.h>
     80 #endif
     81 #include <netinet6/in6_var.h>
     82 #include <netinet/ip6.h>
     83 #include <netinet6/ip6_var.h>
     84 #endif
     85 
     86 #include "ioconf.h"
     87 
     88 static int	faithioctl(struct ifnet *, u_long, void *);
     89 static int	faithoutput(struct ifnet *, struct mbuf *,
     90 		            const struct sockaddr *, const struct rtentry *);
     91 static void	faithrtrequest(int, struct rtentry *,
     92 		               const struct rt_addrinfo *);
     93 
     94 static int	faith_clone_create(struct if_clone *, int);
     95 static int	faith_clone_destroy(struct ifnet *);
     96 
     97 static struct if_clone faith_cloner =
     98     IF_CLONE_INITIALIZER("faith", faith_clone_create, faith_clone_destroy);
     99 
    100 #define	FAITHMTU	1500
    101 
    102 static u_int faith_count;
    103 
    104 /* ARGSUSED */
    105 void
    106 faithattach(int count)
    107 {
    108 
    109 	/*
    110 	 * Nothing to do here, initialization is handled by the
    111 	 * module initialization code in faithinit() below).
    112 	 */
    113 }
    114 
    115 static void
    116 faithinit(void)
    117 {
    118 	if_clone_attach(&faith_cloner);
    119 }
    120 
    121 static int
    122 faithdetach(void)
    123 {
    124 	int error = 0;
    125 
    126 	if (faith_count != 0)
    127 		error = EBUSY;
    128 
    129 	if (error == 0)
    130 		if_clone_detach(&faith_cloner);
    131 
    132 	return error;
    133 }
    134 
    135 static int
    136 faith_clone_create(struct if_clone *ifc, int unit)
    137 {
    138 	struct ifnet *ifp;
    139 
    140 	ifp = if_alloc(IFT_FAITH);
    141 
    142 	if_initname(ifp, ifc->ifc_name, unit);
    143 
    144 	ifp->if_mtu = FAITHMTU;
    145 	/* Change to BROADCAST experimentally to announce its prefix. */
    146 	ifp->if_flags = /* IFF_LOOPBACK */ IFF_BROADCAST | IFF_MULTICAST;
    147 	ifp->if_ioctl = faithioctl;
    148 	ifp->if_output = faithoutput;
    149 	ifp->if_type = IFT_FAITH;
    150 	ifp->if_hdrlen = 0;
    151 	ifp->if_addrlen = 0;
    152 	ifp->if_dlt = DLT_NULL;
    153 	if_attach(ifp);
    154 	if_alloc_sadl(ifp);
    155 	bpf_attach(ifp, DLT_NULL, sizeof(u_int));
    156 	atomic_inc_uint(&faith_count);
    157 	return (0);
    158 }
    159 
    160 int
    161 faith_clone_destroy(struct ifnet *ifp)
    162 {
    163 
    164 	bpf_detach(ifp);
    165 	if_detach(ifp);
    166 	if_free(ifp);
    167 
    168 	atomic_dec_uint(&faith_count);
    169 	return (0);
    170 }
    171 
    172 static int
    173 faithoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
    174     const struct rtentry *rt)
    175 {
    176 	pktqueue_t *pktq;
    177 	size_t pktlen;
    178 	int s, error;
    179 	uint32_t af;
    180 
    181 	if ((m->m_flags & M_PKTHDR) == 0)
    182 		panic("faithoutput no HDR");
    183 	af = dst->sa_family;
    184 	/* BPF write needs to be handled specially */
    185 	if (af == AF_UNSPEC) {
    186 		af = *(mtod(m, int *));
    187 		m_adj(m, sizeof(int));
    188 	}
    189 
    190 	bpf_mtap_af(ifp, af, m, BPF_D_OUT);
    191 
    192 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
    193 		m_freem(m);
    194 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
    195 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
    196 	}
    197 	pktlen = m->m_pkthdr.len;
    198 	if_statadd2(ifp, if_opackets, 1, if_obytes, pktlen);
    199 	switch (af) {
    200 #ifdef INET
    201 	case AF_INET:
    202 		pktq = ip_pktq;
    203 		break;
    204 #endif
    205 #ifdef INET6
    206 	case AF_INET6:
    207 		pktq = ip6_pktq;
    208 		break;
    209 #endif
    210 	default:
    211 		m_freem(m);
    212 		return EAFNOSUPPORT;
    213 	}
    214 
    215 	/* XXX do we need more sanity checks? */
    216 	KASSERT(pktq != NULL);
    217 	m_set_rcvif(m, ifp);
    218 
    219 	s = splnet();
    220 	if (__predict_true(pktq_enqueue(pktq, m, 0))) {
    221 		if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen);
    222 		error = 0;
    223 	} else {
    224 		m_freem(m);
    225 		error = ENOBUFS;
    226 	}
    227 	splx(s);
    228 
    229 	return error;
    230 }
    231 
    232 /* ARGSUSED */
    233 static void
    234 faithrtrequest(int cmd, struct rtentry *rt,
    235     const struct rt_addrinfo *info)
    236 {
    237 	if (rt)
    238 		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
    239 }
    240 
    241 /*
    242  * Process an ioctl request.
    243  */
    244 /* ARGSUSED */
    245 static int
    246 faithioctl(struct ifnet *ifp, u_long cmd, void *data)
    247 {
    248 	struct ifaddr *ifa;
    249 	struct ifreq *ifr = (struct ifreq *)data;
    250 	int error = 0;
    251 
    252 	switch (cmd) {
    253 
    254 	case SIOCINITIFADDR:
    255 		ifa = (struct ifaddr *)data;
    256 		ifa->ifa_rtrequest = faithrtrequest;
    257 		ifp->if_flags |= IFF_UP | IFF_RUNNING;
    258 		/*
    259 		 * Everything else is done at a higher level.
    260 		 */
    261 		break;
    262 
    263 	case SIOCADDMULTI:
    264 	case SIOCDELMULTI:
    265 		if (ifr == 0) {
    266 			error = EAFNOSUPPORT;		/* XXX */
    267 			break;
    268 		}
    269 		switch (ifr->ifr_addr.sa_family) {
    270 #ifdef INET
    271 		case AF_INET:
    272 			break;
    273 #endif
    274 #ifdef INET6
    275 		case AF_INET6:
    276 			break;
    277 #endif
    278 
    279 		default:
    280 			error = EAFNOSUPPORT;
    281 			break;
    282 		}
    283 		break;
    284 
    285 	default:
    286 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
    287 			error = 0;
    288 		break;
    289 	}
    290 	return (error);
    291 }
    292 
    293 #ifdef INET6
    294 /*
    295  * XXX could be slow
    296  * XXX could be layer violation to call sys/net from sys/netinet6
    297  */
    298 int
    299 faithprefix(struct in6_addr *in6)
    300 {
    301 	struct rtentry *rt;
    302 	struct sockaddr_in6 sin6;
    303 	int ret;
    304 
    305 	if (ip6_keepfaith == 0)
    306 		return 0;
    307 
    308 	memset(&sin6, 0, sizeof(sin6));
    309 	sin6.sin6_family = AF_INET6;
    310 	sin6.sin6_len = sizeof(struct sockaddr_in6);
    311 	sin6.sin6_addr = *in6;
    312 	rt = rtalloc1((struct sockaddr *)&sin6, 0);
    313 	if (rt && rt->rt_ifp && rt->rt_ifp->if_type == IFT_FAITH &&
    314 	    (rt->rt_ifp->if_flags & IFF_UP) != 0)
    315 		ret = 1;
    316 	else
    317 		ret = 0;
    318 	if (rt)
    319 		rt_unref(rt);
    320 	return ret;
    321 }
    322 #endif
    323 
    324 /*
    325  * Module infrastructure
    326  */
    327 #include "if_module.h"
    328 
    329 IF_MODULE(MODULE_CLASS_DRIVER, faith, NULL)
    330