NetBSD/sys/net/if_tun.c

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/*
* Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk>
* Nottingham University 1987.
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*
* 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 it's 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/select mode of
* operation though.
*
* $Id: if_tun.c,v 1.10 1994/02/28 07:16:10 andrew Exp $
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*/
#include "tun.h"
#if NTUN > 0
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/buf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <sys/select.h>
#include <sys/file.h>
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#include <machine/cpu.h>
#include <net/if.h>
#include <net/netisr.h>
#include <net/route.h>
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#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
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#endif
#ifdef NS
#include <netns/ns.h>
#include <netns/ns_if.h>
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#endif
#include "bpfilter.h"
#if NBPFILTER > 0
#include <sys/time.h>
#include <net/bpf.h>
#endif
#include <net/if_tun.h>
#define TUNDEBUG if (tundebug) printf
int tundebug = 0;
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struct tun_softc tunctl[NTUN];
extern int ifqmaxlen;
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int tunopen __P((dev_t, int, int, struct proc *));
int tunclose __P((dev_t, int));
int tunoutput __P((struct ifnet *, struct mbuf *, struct sockaddr *));
int tunread __P((dev_t, struct uio *));
int tunwrite __P((dev_t, struct uio *));
int tuncioctl __P((dev_t, int, caddr_t, int));
int tunioctl __P((struct ifnet *, int, caddr_t, int));
int tunselect __P((dev_t, int));
void tunattach __P((int));
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static int tuninit __P((int));
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void
tunattach(unused)
int unused;
{
register int i;
struct ifnet *ifp;
struct sockaddr_in *sin;
for (i = 0; i < NTUN; i++) {
tunctl[i].tun_flags = TUN_INITED;
ifp = &tunctl[i].tun_if;
ifp->if_unit = i;
ifp->if_name = "tun";
ifp->if_mtu = TUNMTU;
ifp->if_ioctl = tunioctl;
ifp->if_output = tunoutput;
ifp->if_flags = IFF_POINTOPOINT;
ifp->if_snd.ifq_maxlen = ifqmaxlen;
ifp->if_collisions = 0;
ifp->if_ierrors = 0;
ifp->if_oerrors = 0;
ifp->if_ipackets = 0;
ifp->if_opackets = 0;
if_attach(ifp);
#if NBPFILTER > 0
bpfattach(&tunctl[i].tun_bpf, ifp, DLT_NULL, sizeof(u_int));
#endif
}
}
/*
* tunnel open - must be superuser & the device must be
* configured in
*/
int
tunopen(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
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{
struct ifnet *ifp;
struct tun_softc *tp;
register int unit, error;
if (error = suser(p->p_ucred, &p->p_acflag))
return (error);
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if ((unit = minor(dev)) >= NTUN)
return (ENXIO);
tp = &tunctl[unit];
if (tp->tun_flags & TUN_OPEN)
return ENXIO;
ifp = &tp->tun_if;
tp->tun_flags |= TUN_OPEN;
TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit);
return (0);
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}
/*
* tunclose - close the device - mark i/f down & delete
* routing info
*/
int
tunclose(dev, flag)
dev_t dev;
int flag;
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{
register int unit = minor(dev), s;
struct tun_softc *tp = &tunctl[unit];
struct ifnet *ifp = &tp->tun_if;
struct mbuf *m;
tp->tun_flags &= ~TUN_OPEN;
/*
* junk all pending output
*/
do {
s = splimp();
IF_DEQUEUE(&ifp->if_snd, m);
splx(s);
if (m)
m_freem(m);
} while (m);
if (ifp->if_flags & IFF_UP) {
s = splimp();
if_down(ifp);
if (ifp->if_flags & IFF_RUNNING) {
rtinit(ifp->if_addrlist, (int)RTM_DELETE,
tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
}
splx(s);
}
tp->tun_pgrp = 0;
selwakeup(&tp->tun_rsel);
TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit);
return (0);
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}
static int
tuninit(unit)
int unit;
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{
struct tun_softc *tp = &tunctl[unit];
struct ifnet *ifp = &tp->tun_if;
register struct ifaddr *ifa;
TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit);
ifp->if_flags |= IFF_UP | IFF_RUNNING;
for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
struct sockaddr_in *si;
si = (struct sockaddr_in *)ifa->ifa_addr;
if (si && 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;
}
return 0;
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}
/*
* Process an ioctl request.
*/
int
tunioctl(ifp, cmd, data, flag)
struct ifnet *ifp;
int cmd;
caddr_t data;
int flag;
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{
struct tun_softc *tp = &tunctl[ifp->if_unit];
int error = 0, s;
s = splimp();
switch(cmd) {
case SIOCSIFADDR:
tuninit(ifp->if_unit);
break;
case SIOCSIFDSTADDR:
tp->tun_flags |= TUN_DSTADDR;
TUNDEBUG("%s%d: destination address set\n", ifp->if_name,
ifp->if_unit);
break;
default:
error = EINVAL;
}
splx(s);
return (error);
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}
/*
* tunoutput - queue packets from higher level ready to put out.
*/
int
tunoutput(ifp, m0, dst)
struct ifnet *ifp;
struct mbuf *m0;
struct sockaddr *dst;
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{
struct tun_softc *tp = &tunctl[ifp->if_unit];
struct proc *p;
int s;
TUNDEBUG ("%s%d: tunoutput\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);
m_freem (m0);
return EHOSTDOWN;
}
#if NBPFILTER > 0
if (tp->tun_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;
u_int af = dst->sa_family;
m.m_next = m0;
m.m_len = 4;
m.m_data = (char *)&af;
bpf_mtap(tp->tun_bpf, &m);
}
#endif
switch(dst->sa_family) {
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#ifdef INET
case AF_INET:
s = splimp();
if (IF_QFULL(&ifp->if_snd)) {
IF_DROP(&ifp->if_snd);
m_freem(m0);
splx(s);
ifp->if_collisions++;
return (ENOBUFS);
}
IF_ENQUEUE(&ifp->if_snd, m0);
splx(s);
ifp->if_opackets++;
break;
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#endif
default:
m_freem(m0);
return EAFNOSUPPORT;
}
if (tp->tun_flags & TUN_RWAIT) {
tp->tun_flags &= ~TUN_RWAIT;
wakeup((caddr_t)tp);
}
if (tp->tun_flags & TUN_ASYNC && tp->tun_pgrp) {
if (tp->tun_pgrp > 0)
gsignal(tp->tun_pgrp, SIGIO);
else if (p = pfind(-tp->tun_pgrp))
psignal(p, SIGIO);
}
selwakeup(&tp->tun_rsel);
return 0;
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}
/*
* the cdevsw interface is now pretty minimal.
*/
int
tuncioctl(dev, cmd, data, flag)
dev_t dev;
int cmd;
caddr_t data;
int flag;
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{
int unit = minor(dev), s;
struct tun_softc *tp = &tunctl[unit];
switch (cmd) {
case TUNSDEBUG:
tundebug = *(int *)data;
break;
case TUNGDEBUG:
*(int *)data = tundebug;
break;
case FIONBIO:
if (*(int *)data)
tp->tun_flags |= TUN_NBIO;
else
tp->tun_flags &= ~TUN_NBIO;
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)
*(int *)data = tp->tun_if.if_snd.ifq_head->m_len;
else
*(int *)data = 0;
splx(s);
break;
case TIOCSPGRP:
tp->tun_pgrp = *(int *)data;
break;
case TIOCGPGRP:
*(int *)data = tp->tun_pgrp;
break;
default:
return (ENOTTY);
}
return (0);
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}
/*
* The cdevsw read interface - reads a packet at a time, or at
* least as much of a packet as can be read.
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*/
int
tunread(dev, uio)
dev_t dev;
struct uio *uio;
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{
int unit = minor(dev);
struct tun_softc *tp = &tunctl[unit];
struct ifnet *ifp = &tp->tun_if;
struct mbuf *m, *m0;
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, m0);
if (m0 == 0) {
if (tp->tun_flags & TUN_NBIO) {
splx(s);
return EWOULDBLOCK;
}
tp->tun_flags |= TUN_RWAIT;
tsleep((caddr_t)tp, PZERO + 1, "tunread", 0);
}
} while (m0 == 0);
splx(s);
while (m0 && uio->uio_resid > 0 && error == 0) {
len = MIN(uio->uio_resid, m0->m_len);
if (len == 0)
break;
error = uiomove(mtod(m0, caddr_t), len, uio);
MFREE(m0, m);
m0 = m;
}
if (m0) {
TUNDEBUG("Dropping mbuf\n");
m_freem(m0);
}
return error;
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}
/*
* the cdevsw write interface - an atomic write is a packet - or else!
*/
int
tunwrite(dev, uio)
dev_t dev;
struct uio *uio;
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{
int unit = minor (dev);
struct ifnet *ifp = &tunctl[unit].tun_if;
struct mbuf *top, **mp, *m;
int error=0, s, tlen, mlen;
TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
if (uio->uio_resid < 0 || uio->uio_resid > TUNMTU) {
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 = &top;
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);
return error;
}
top->m_pkthdr.len = tlen;
top->m_pkthdr.rcvif = ifp;
#if NBPFILTER > 0
if (tunctl[unit].tun_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;
u_int af = AF_INET;
m.m_next = top;
m.m_len = 4;
m.m_data = (char *)&af;
bpf_mtap(tunctl[unit].tun_bpf, &m);
}
#endif
s = splimp();
if (IF_QFULL (&ipintrq)) {
IF_DROP(&ipintrq);
splx(s);
ifp->if_collisions++;
m_freem(top);
return ENOBUFS;
}
IF_ENQUEUE(&ipintrq, top);
splx(s);
ifp->if_ipackets++;
schednetisr(NETISR_IP);
return error;
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}
/*
* tunselect - the select 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.
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*/
int
tunselect(dev, rw)
dev_t dev;
int rw;
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{
int unit = minor(dev), s;
struct tun_softc *tp = &tunctl[unit];
struct ifnet *ifp = &tp->tun_if;
s = splimp();
TUNDEBUG("%s%d: tunselect\n", ifp->if_name, ifp->if_unit);
switch (rw) {
case FREAD:
if (ifp->if_snd.ifq_len > 0) {
splx(s);
TUNDEBUG("%s%d: tunselect q=%d\n", ifp->if_name,
ifp->if_unit, ifp->if_snd.ifq_len);
return 1;
}
selrecord(curproc, &tp->tun_rsel);
break;
case FWRITE:
splx(s);
return 1;
}
splx(s);
TUNDEBUG("%s%d: tunselect waiting\n", ifp->if_name, ifp->if_unit);
return 0;
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}
#endif /* NTUN */