/* $NetBSD: if_tun.c,v 1.14 1994/06/29 06:36:25 cgd Exp $ */ /* * Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk> * Nottingham University 1987. * * This source may be freely distributed, however I would be interested * in any changes that are made. * * This driver takes packets off the IP i/f and hands them up to a * user process to have its wicked way with. This driver has it's * roots in a similar driver written by Phil Cockcroft (formerly) at * UCL. This driver is based much more on read/write/poll mode of * operation though. * * $FreeBSD$ */ #include "opt_inet.h" #include "opt_mac.h" #include <sys/param.h> #include <sys/proc.h> #include <sys/systm.h> #include <sys/mac.h> #include <sys/mbuf.h> #include <sys/module.h> #include <sys/socket.h> #include <sys/filio.h> #include <sys/sockio.h> #include <sys/ttycom.h> #include <sys/poll.h> #include <sys/signalvar.h> #include <sys/filedesc.h> #include <sys/kernel.h> #include <sys/sysctl.h> #include <sys/conf.h> #include <sys/uio.h> #include <sys/vnode.h> #include <sys/malloc.h> #include <machine/bus.h> /* XXX Shouldn't really be required ! */ #include <sys/rman.h> #include <net/if.h> #include <net/if_types.h> #include <net/route.h> #include <net/intrq.h> #ifdef INET #include <netinet/in.h> #endif #include <net/bpf.h> #include <net/if_tunvar.h> #include <net/if_tun.h> #define TUNDEBUG if (tundebug) printf #define TUNNAME "tun" #define TUN_MAXUNIT 0x7fff /* ifp->if_unit is only 15 bits */ static MALLOC_DEFINE(M_TUN, TUNNAME, "Tunnel Interface"); static int tundebug = 0; static struct tun_softc *tunhead = NULL; static struct rman tununits; static udev_t tunbasedev = NOUDEV; SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, ""); static void tunclone(void *arg, char *name, int namelen, dev_t *dev); static void tuncreate(dev_t dev); static int tunifioctl(struct ifnet *, u_long, caddr_t); static int tuninit(struct ifnet *); static int tunmodevent(module_t, int, void *); static int tunoutput(struct ifnet *, struct mbuf *, struct sockaddr *, struct rtentry *rt); static void tunstart(struct ifnet *); static d_open_t tunopen; static d_close_t tunclose; static d_read_t tunread; static d_write_t tunwrite; static d_ioctl_t tunioctl; static d_poll_t tunpoll; #define CDEV_MAJOR 52 static struct cdevsw tun_cdevsw = { /* open */ tunopen, /* close */ tunclose, /* read */ tunread, /* write */ tunwrite, /* ioctl */ tunioctl, /* poll */ tunpoll, /* mmap */ nommap, /* strategy */ nostrategy, /* name */ TUNNAME, /* maj */ CDEV_MAJOR, /* dump */ nodump, /* psize */ nopsize, /* flags */ 0, }; static void tunclone(void *arg, char *name, int namelen, dev_t *dev) { struct resource *r; int err; int u; if (*dev != NODEV) return; if (strcmp(name, TUNNAME) == 0) { r = rman_reserve_resource(&tununits, 0, TUN_MAXUNIT, 1, RF_ALLOCATED | RF_ACTIVE, NULL); u = rman_get_start(r); err = rman_release_resource(r); KASSERT(err == 0, ("Unexpected failure releasing resource")); *dev = makedev(CDEV_MAJOR, unit2minor(u)); if ((*dev)->si_flags & SI_NAMED) return; /* Already make_dev()d */ } else if (dev_stdclone(name, NULL, TUNNAME, &u) != 1) return; /* Don't recognise the name */ *dev = make_dev(&tun_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, "tun%d", u); /* * All devices depend on tunbasedev so that we can simply * destroy_dev() this device at module unload time to get * rid of all our make_dev()d resources. */ if (tunbasedev == NOUDEV) tunbasedev = (*dev)->si_udev; else { (*dev)->si_flags |= SI_CHEAPCLONE; dev_depends(udev2dev(tunbasedev, 0), *dev); } } static int tunmodevent(module_t mod, int type, void *data) { static eventhandler_tag tag; struct tun_softc *tp; dev_t dev; int err; switch (type) { case MOD_LOAD: tag = EVENTHANDLER_REGISTER(dev_clone, tunclone, 0, 1000); if (tag == NULL) return (ENOMEM); if (!devfs_present) { err = cdevsw_add(&tun_cdevsw); if (err != 0) { EVENTHANDLER_DEREGISTER(dev_clone, tag); return (err); } } tununits.rm_type = RMAN_ARRAY; tununits.rm_descr = "open if_tun units"; err = rman_init(&tununits); if (err != 0) { cdevsw_remove(&tun_cdevsw); EVENTHANDLER_DEREGISTER(dev_clone, tag); return (err); } err = rman_manage_region(&tununits, 0, TUN_MAXUNIT); if (err != 0) { printf("%s: tununits: rman_manage_region: Failed %d\n", TUNNAME, err); rman_fini(&tununits); cdevsw_remove(&tun_cdevsw); EVENTHANDLER_DEREGISTER(dev_clone, tag); return (err); } break; case MOD_UNLOAD: err = rman_fini(&tununits); if (err != 0) return (err); EVENTHANDLER_DEREGISTER(dev_clone, tag); while (tunhead != NULL) { KASSERT((tunhead->tun_flags & TUN_OPEN) == 0, ("tununits is out of sync - unit %d", tunhead->tun_if.if_unit)); tp = tunhead; dev = makedev(tun_cdevsw.d_maj, unit2minor(tp->tun_if.if_unit)); KASSERT(dev->si_drv1 == tp, ("Bad makedev result")); tunhead = tp->next; bpfdetach(&tp->tun_if); if_detach(&tp->tun_if); KASSERT(dev->si_flags & SI_NAMED, ("Missing make_dev")); free(tp, M_TUN); } /* * Destroying tunbasedev results in all of our make_dev()s * conveniently going away. */ if (tunbasedev != NOUDEV) destroy_dev(udev2dev(tunbasedev, 0)); if (!devfs_present) cdevsw_remove(&tun_cdevsw); break; } return 0; } static moduledata_t tun_mod = { "if_tun", tunmodevent, 0 }; DECLARE_MODULE(if_tun, tun_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); static void tunstart(struct ifnet *ifp) { struct tun_softc *tp = ifp->if_softc; if (tp->tun_flags & TUN_RWAIT) { tp->tun_flags &= ~TUN_RWAIT; wakeup((caddr_t)tp); } if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio) pgsigio(&tp->tun_sigio, SIGIO, 0); selwakeup(&tp->tun_rsel); } static void tuncreate(dev_t dev) { struct tun_softc *sc; struct ifnet *ifp; if (!(dev->si_flags & SI_NAMED)) dev = make_dev(&tun_cdevsw, minor(dev), UID_UUCP, GID_DIALER, 0600, "tun%d", dev2unit(dev)); MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK | M_ZERO); sc->tun_flags = TUN_INITED; sc->next = tunhead; tunhead = sc; ifp = &sc->tun_if; ifp->if_unit = dev2unit(dev); ifp->if_name = TUNNAME; ifp->if_mtu = TUNMTU; ifp->if_ioctl = tunifioctl; ifp->if_output = tunoutput; ifp->if_start = tunstart; ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST; ifp->if_type = IFT_PPP; ifp->if_snd.ifq_maxlen = ifqmaxlen; ifp->if_softc = sc; if_attach(ifp); bpfattach(ifp, DLT_NULL, sizeof(u_int)); dev->si_drv1 = sc; } static int tunopen(dev_t dev, int flag, int mode, struct thread *td) { struct resource *r; struct ifnet *ifp; struct tun_softc *tp; int unit; unit = dev2unit(dev); if (unit > TUN_MAXUNIT) return (ENXIO); r = rman_reserve_resource(&tununits, unit, unit, 1, RF_ALLOCATED | RF_ACTIVE, NULL); if (r == NULL) return (EBUSY); dev->si_flags &= ~SI_CHEAPCLONE; tp = dev->si_drv1; if (!tp) { tuncreate(dev); tp = dev->si_drv1; } KASSERT(!(tp->tun_flags & TUN_OPEN), ("Resource & flags out-of-sync")); tp->r_unit = r; tp->tun_pid = td->td_proc->p_pid; ifp = &tp->tun_if; tp->tun_flags |= TUN_OPEN; TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit); return (0); } /* * tunclose - close the device - mark i/f down & delete * routing info */ static int tunclose(dev_t dev, int foo, int bar, struct thread *td) { struct tun_softc *tp; struct ifnet *ifp; int s; int err; tp = dev->si_drv1; ifp = &tp->tun_if; KASSERT(tp->r_unit, ("Unit %d not marked open", ifp->if_unit)); tp->tun_flags &= ~TUN_OPEN; tp->tun_pid = 0; /* * junk all pending output */ IF_DRAIN(&ifp->if_snd); if (ifp->if_flags & IFF_UP) { s = splimp(); if_down(ifp); splx(s); } if (ifp->if_flags & IFF_RUNNING) { register struct ifaddr *ifa; s = splimp(); /* find internet addresses and delete routes */ TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) if (ifa->ifa_addr->sa_family == AF_INET) rtinit(ifa, (int)RTM_DELETE, tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0); ifp->if_flags &= ~IFF_RUNNING; splx(s); } funsetown(&tp->tun_sigio); selwakeup(&tp->tun_rsel); TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit); err = rman_release_resource(tp->r_unit); KASSERT(err == 0, ("Unit %d failed to release", ifp->if_unit)); return (0); } static int tuninit(struct ifnet *ifp) { struct tun_softc *tp = ifp->if_softc; register struct ifaddr *ifa; int error = 0; TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit); ifp->if_flags |= IFF_UP | IFF_RUNNING; getmicrotime(&ifp->if_lastchange); for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa; ifa = TAILQ_NEXT(ifa, ifa_link)) { if (ifa->ifa_addr == NULL) error = EFAULT; /* XXX: Should maybe return straight off? */ else { #ifdef INET if (ifa->ifa_addr->sa_family == AF_INET) { struct sockaddr_in *si; si = (struct sockaddr_in *)ifa->ifa_addr; if (si->sin_addr.s_addr) tp->tun_flags |= TUN_IASET; si = (struct sockaddr_in *)ifa->ifa_dstaddr; if (si && si->sin_addr.s_addr) tp->tun_flags |= TUN_DSTADDR; } #endif } } return (error); } /* * Process an ioctl request. */ static int tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data) { struct ifreq *ifr = (struct ifreq *)data; struct tun_softc *tp = ifp->if_softc; struct ifstat *ifs; int error = 0, s; s = splimp(); switch(cmd) { case SIOCGIFSTATUS: ifs = (struct ifstat *)data; if (tp->tun_pid) sprintf(ifs->ascii + strlen(ifs->ascii), "\tOpened by PID %d\n", tp->tun_pid); break; case SIOCSIFADDR: error = tuninit(ifp); TUNDEBUG("%s%d: address set, error=%d\n", ifp->if_name, ifp->if_unit, error); break; case SIOCSIFDSTADDR: error = tuninit(ifp); TUNDEBUG("%s%d: destination address set, error=%d\n", ifp->if_name, ifp->if_unit, error); break; case SIOCSIFMTU: ifp->if_mtu = ifr->ifr_mtu; TUNDEBUG("%s%d: mtu set\n", ifp->if_name, ifp->if_unit); break; case SIOCSIFFLAGS: case SIOCADDMULTI: case SIOCDELMULTI: break; default: error = EINVAL; } splx(s); return (error); } /* * tunoutput - queue packets from higher level ready to put out. */ static int tunoutput( struct ifnet *ifp, struct mbuf *m0, struct sockaddr *dst, struct rtentry *rt) { struct tun_softc *tp = ifp->if_softc; #ifdef MAC int error; #endif TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit); #ifdef MAC error = mac_check_ifnet_transmit(ifp, m0); if (error) { m_freem(m0); return (error); } #endif if ((tp->tun_flags & TUN_READY) != TUN_READY) { TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, ifp->if_unit, tp->tun_flags); m_freem (m0); return (EHOSTDOWN); } if ((ifp->if_flags & IFF_UP) != IFF_UP) { m_freem (m0); return (EHOSTDOWN); } /* BPF write needs to be handled specially */ if (dst->sa_family == AF_UNSPEC) { dst->sa_family = *(mtod(m0, int *)); m0->m_len -= sizeof(int); m0->m_pkthdr.len -= sizeof(int); m0->m_data += sizeof(int); } if (ifp->if_bpf) { /* * We need to prepend the address family as * a four byte field. Cons up a dummy header * to pacify bpf. This is safe because bpf * will only read from the mbuf (i.e., it won't * try to free it or keep a pointer to it). */ struct mbuf m; uint32_t af = dst->sa_family; m.m_next = m0; m.m_len = 4; m.m_data = (char *)⁡ BPF_MTAP(ifp, &m); } /* prepend sockaddr? this may abort if the mbuf allocation fails */ if (tp->tun_flags & TUN_LMODE) { /* allocate space for sockaddr */ M_PREPEND(m0, dst->sa_len, M_DONTWAIT); /* if allocation failed drop packet */ if (m0 == NULL) { ifp->if_iqdrops++; ifp->if_oerrors++; return (ENOBUFS); } else { bcopy(dst, m0->m_data, dst->sa_len); } } if (tp->tun_flags & TUN_IFHEAD) { /* Prepend the address family */ M_PREPEND(m0, 4, M_DONTWAIT); /* if allocation failed drop packet */ if (m0 == NULL) { ifp->if_iqdrops++; ifp->if_oerrors++; return (ENOBUFS); } else *(u_int32_t *)m0->m_data = htonl(dst->sa_family); } else { #ifdef INET if (dst->sa_family != AF_INET) #endif { m_freem(m0); return (EAFNOSUPPORT); } } if (! IF_HANDOFF(&ifp->if_snd, m0, ifp)) { ifp->if_collisions++; return (ENOBUFS); } ifp->if_opackets++; return (0); } /* * the cdevsw interface is now pretty minimal. */ static int tunioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td) { int s; int error; struct tun_softc *tp = dev->si_drv1; struct tuninfo *tunp; switch (cmd) { case TUNSIFINFO: tunp = (struct tuninfo *)data; if (tunp->mtu < IF_MINMTU) return (EINVAL); if (tp->tun_if.if_mtu != tunp->mtu && (error = suser(td)) != 0) return (error); tp->tun_if.if_mtu = tunp->mtu; tp->tun_if.if_type = tunp->type; tp->tun_if.if_baudrate = tunp->baudrate; break; case TUNGIFINFO: tunp = (struct tuninfo *)data; tunp->mtu = tp->tun_if.if_mtu; tunp->type = tp->tun_if.if_type; tunp->baudrate = tp->tun_if.if_baudrate; break; case TUNSDEBUG: tundebug = *(int *)data; break; case TUNGDEBUG: *(int *)data = tundebug; break; case TUNSLMODE: if (*(int *)data) { tp->tun_flags |= TUN_LMODE; tp->tun_flags &= ~TUN_IFHEAD; } else tp->tun_flags &= ~TUN_LMODE; break; case TUNSIFHEAD: if (*(int *)data) { tp->tun_flags |= TUN_IFHEAD; tp->tun_flags &= ~TUN_LMODE; } else tp->tun_flags &= ~TUN_IFHEAD; break; case TUNGIFHEAD: *(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0; break; case TUNSIFMODE: /* deny this if UP */ if (tp->tun_if.if_flags & IFF_UP) return(EBUSY); switch (*(int *)data & ~IFF_MULTICAST) { case IFF_POINTOPOINT: case IFF_BROADCAST: tp->tun_if.if_flags &= ~(IFF_BROADCAST|IFF_POINTOPOINT|IFF_MULTICAST); tp->tun_if.if_flags |= *(int *)data; break; default: return(EINVAL); } break; case TUNSIFPID: tp->tun_pid = curthread->td_proc->p_pid; break; case FIONBIO: break; case FIOASYNC: if (*(int *)data) tp->tun_flags |= TUN_ASYNC; else tp->tun_flags &= ~TUN_ASYNC; break; case FIONREAD: s = splimp(); if (tp->tun_if.if_snd.ifq_head) { struct mbuf *mb = tp->tun_if.if_snd.ifq_head; for( *(int *)data = 0; mb != 0; mb = mb->m_next) *(int *)data += mb->m_len; } else *(int *)data = 0; splx(s); break; case FIOSETOWN: return (fsetown(*(int *)data, &tp->tun_sigio)); case FIOGETOWN: *(int *)data = fgetown(&tp->tun_sigio); return (0); /* This is deprecated, FIOSETOWN should be used instead. */ case TIOCSPGRP: return (fsetown(-(*(int *)data), &tp->tun_sigio)); /* This is deprecated, FIOGETOWN should be used instead. */ case TIOCGPGRP: *(int *)data = -fgetown(&tp->tun_sigio); return (0); default: return (ENOTTY); } return (0); } /* * The cdevsw read interface - reads a packet at a time, or at * least as much of a packet as can be read. */ static int tunread(dev_t dev, struct uio *uio, int flag) { struct tun_softc *tp = dev->si_drv1; struct ifnet *ifp = &tp->tun_if; struct mbuf *m; int error=0, len, s; TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit); if ((tp->tun_flags & TUN_READY) != TUN_READY) { TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, ifp->if_unit, tp->tun_flags); return (EHOSTDOWN); } tp->tun_flags &= ~TUN_RWAIT; s = splimp(); do { IF_DEQUEUE(&ifp->if_snd, m); if (m == NULL) { if (flag & IO_NDELAY) { splx(s); return (EWOULDBLOCK); } tp->tun_flags |= TUN_RWAIT; if((error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1), "tunread", 0)) != 0) { splx(s); return (error); } } } while (m == NULL); splx(s); while (m && uio->uio_resid > 0 && error == 0) { len = min(uio->uio_resid, m->m_len); if (len != 0) error = uiomove(mtod(m, caddr_t), len, uio); m = m_free(m); } if (m) { TUNDEBUG("%s%d: Dropping mbuf\n", ifp->if_name, ifp->if_unit); m_freem(m); } return (error); } /* * the cdevsw write interface - an atomic write is a packet - or else! */ static int tunwrite(dev_t dev, struct uio *uio, int flag) { struct tun_softc *tp = dev->si_drv1; struct ifnet *ifp = &tp->tun_if; struct mbuf *top, **mp, *m; int error=0, tlen, mlen; uint32_t family; TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit); if ((ifp->if_flags & IFF_UP) != IFF_UP) /* ignore silently */ return (0); if (uio->uio_resid == 0) return (0); if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) { TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit, uio->uio_resid); return (EIO); } tlen = uio->uio_resid; /* get a header mbuf */ MGETHDR(m, M_DONTWAIT, MT_DATA); if (m == NULL) return (ENOBUFS); mlen = MHLEN; top = 0; mp = ⊤ while (error == 0 && uio->uio_resid > 0) { m->m_len = min(mlen, uio->uio_resid); error = uiomove(mtod (m, caddr_t), m->m_len, uio); *mp = m; mp = &m->m_next; if (uio->uio_resid > 0) { MGET (m, M_DONTWAIT, MT_DATA); if (m == 0) { error = ENOBUFS; break; } mlen = MLEN; } } if (error) { if (top) m_freem (top); ifp->if_ierrors++; return (error); } top->m_pkthdr.len = tlen; top->m_pkthdr.rcvif = ifp; #ifdef MAC mac_create_mbuf_from_ifnet(ifp, top); #endif if (ifp->if_bpf) { if (tp->tun_flags & TUN_IFHEAD) { /* * Conveniently, we already have a 4-byte address * family prepended to our packet ! * Inconveniently, it's in the wrong byte order ! */ if ((top = m_pullup(top, sizeof(family))) == NULL) return (ENOBUFS); *mtod(top, u_int32_t *) = ntohl(*mtod(top, u_int32_t *)); BPF_MTAP(ifp, top); *mtod(top, u_int32_t *) = htonl(*mtod(top, u_int32_t *)); } else { /* * We need to prepend the address family as * a four byte field. Cons up a dummy header * to pacify bpf. This is safe because bpf * will only read from the mbuf (i.e., it won't * try to free it or keep a pointer to it). */ struct mbuf m; uint32_t af = AF_INET; m.m_next = top; m.m_len = 4; m.m_data = (char *)⁡ BPF_MTAP(ifp, &m); } } if (tp->tun_flags & TUN_IFHEAD) { if (top->m_len < sizeof(family) && (top = m_pullup(top, sizeof(family))) == NULL) return (ENOBUFS); family = ntohl(*mtod(top, u_int32_t *)); m_adj(top, sizeof(family)); } else family = AF_INET; ifp->if_ibytes += top->m_pkthdr.len; ifp->if_ipackets++; return (family_enqueue(family, top)); } /* * tunpoll - the poll interface, this is only useful on reads * really. The write detect always returns true, write never blocks * anyway, it either accepts the packet or drops it. */ static int tunpoll(dev_t dev, int events, struct thread *td) { int s; struct tun_softc *tp = dev->si_drv1; struct ifnet *ifp = &tp->tun_if; int revents = 0; s = splimp(); TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit); if (events & (POLLIN | POLLRDNORM)) { if (ifp->if_snd.ifq_len > 0) { TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name, ifp->if_unit, ifp->if_snd.ifq_len); revents |= events & (POLLIN | POLLRDNORM); } else { TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name, ifp->if_unit); selrecord(td, &tp->tun_rsel); } } if (events & (POLLOUT | POLLWRNORM)) revents |= events & (POLLOUT | POLLWRNORM); splx(s); return (revents); }