/* $NetBSD: nit.c,v 1.2 2018/04/07 22:37:29 christos Exp $ */
/* nit.c
Network Interface Tap (NIT) network interface code, by Ted Lemon
with one crucial tidbit of help from Stu Grossmen. */
/*
* Copyright (c) 2004-2017 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1996-2003 by Internet Software Consortium
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Internet Systems Consortium, Inc.
* 950 Charter Street
* Redwood City, CA 94063
* <info@isc.org>
* https://www.isc.org/
*
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: nit.c,v 1.2 2018/04/07 22:37:29 christos Exp $");
#include "dhcpd.h"
#if defined (USE_NIT_SEND) || defined (USE_NIT_RECEIVE)
#include <sys/ioctl.h>
#include <sys/uio.h>
#include <sys/time.h>
#include <net/nit.h>
#include <net/nit_if.h>
#include <net/nit_pf.h>
#include <net/nit_buf.h>
#include <sys/stropts.h>
#include <net/packetfilt.h>
#include <netinet/in_systm.h>
#include "includes/netinet/ip.h"
#include "includes/netinet/udp.h"
#include "includes/netinet/if_ether.h"
/* Reinitializes the specified interface after an address change. This
is not required for packet-filter APIs. */
#ifdef USE_NIT_SEND
void if_reinitialize_send (info)
struct interface_info *info;
{
}
#endif
#ifdef USE_NIT_RECEIVE
void if_reinitialize_receive (info)
struct interface_info *info;
{
}
#endif
/* Called by get_interface_list for each interface that's discovered.
Opens a packet filter for each interface and adds it to the select
mask. */
int if_register_nit (info)
struct interface_info *info;
{
int sock;
char filename[50];
struct ifreq ifr;
struct strioctl sio;
/* Open a NIT device */
sock = open ("/dev/nit", O_RDWR);
if (sock < 0)
log_fatal ("Can't open NIT device for %s: %m", info -> name);
/* Set the NIT device to point at this interface. */
sio.ic_cmd = NIOCBIND;
sio.ic_len = sizeof *(info -> ifp);
sio.ic_dp = (char *)(info -> ifp);
sio.ic_timout = INFTIM;
if (ioctl (sock, I_STR, &sio) < 0)
log_fatal ("Can't attach interface %s to nit device: %m",
info -> name);
/* Get the low-level address... */
sio.ic_cmd = SIOCGIFADDR;
sio.ic_len = sizeof ifr;
sio.ic_dp = (char *)𝔦
sio.ic_timout = INFTIM;
if (ioctl (sock, I_STR, &sio) < 0)
log_fatal ("Can't get physical layer address for %s: %m",
info -> name);
/* XXX code below assumes ethernet interface! */
info -> hw_address.hlen = 7;
info -> hw_address.hbuf [0] = ARPHRD_ETHER;
memcpy (&info -> hw_address.hbuf [1],
ifr.ifr_ifru.ifru_addr.sa_data, 6);
if (ioctl (sock, I_PUSH, "pf") < 0)
log_fatal ("Can't push packet filter onto NIT for %s: %m",
info -> name);
return sock;
}
#endif /* USE_NIT_SEND || USE_NIT_RECEIVE */
#ifdef USE_NIT_SEND
void if_register_send (info)
struct interface_info *info;
{
/* If we're using the nit API for sending and receiving,
we don't need to register this interface twice. */
#ifndef USE_NIT_RECEIVE
struct packetfilt pf;
struct strioctl sio;
info -> wfdesc = if_register_nit (info);
pf.Pf_Priority = 0;
pf.Pf_FilterLen = 1;
pf.Pf_Filter [0] = ENF_PUSHZERO;
/* Set up an NIT filter that rejects everything... */
sio.ic_cmd = NIOCSETF;
sio.ic_len = sizeof pf;
sio.ic_dp = (char *)&pf;
sio.ic_timout = INFTIM;
if (ioctl (info -> wfdesc, I_STR, &sio) < 0)
log_fatal ("Can't set NIT filter: %m");
#else
info -> wfdesc = info -> rfdesc;
#endif
if (!quiet_interface_discovery)
log_info ("Sending on NIT/%s%s%s",
print_hw_addr (info -> hw_address.hbuf [0],
info -> hw_address.hlen - 1,
&info -> hw_address.hbuf [1]),
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
void if_deregister_send (info)
struct interface_info *info;
{
/* If we're using the nit API for sending and receiving,
we don't need to register this interface twice. */
#ifndef USE_NIT_RECEIVE
close (info -> wfdesc);
#endif
info -> wfdesc = -1;
if (!quiet_interface_discovery)
log_info ("Disabling output on NIT/%s%s%s",
print_hw_addr (info -> hw_address.hbuf [0],
info -> hw_address.hlen - 1,
&info -> hw_address.hbuf [1]),
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
#endif /* USE_NIT_SEND */
#ifdef USE_NIT_RECEIVE
/* Packet filter program...
XXX Changes to the filter program may require changes to the constant
offsets used in if_register_send to patch the NIT program! XXX */
#if defined(RELAY_PORT)
#error "Relay port is not yet supported for NIT"
#endif
void if_register_receive (info)
struct interface_info *info;
{
int flag = 1;
u_int32_t x;
struct packetfilt pf;
struct strioctl sio;
u_int16_t addr [2];
struct timeval t;
/* Open a NIT device and hang it on this interface... */
info -> rfdesc = if_register_nit (info);
/* Set the snap length to 0, which means always take the whole
packet. */
x = 0;
if (ioctl (info -> rfdesc, NIOCSSNAP, &x) < 0)
log_fatal ("Can't set NIT snap length on %s: %m", info -> name);
/* Set the stream to byte stream mode */
if (ioctl (info -> rfdesc, I_SRDOPT, RMSGN) != 0)
log_info ("I_SRDOPT failed on %s: %m", info -> name);
#if 0
/* Push on the chunker... */
if (ioctl (info -> rfdesc, I_PUSH, "nbuf") < 0)
log_fatal ("Can't push chunker onto NIT STREAM: %m");
/* Set the timeout to zero. */
t.tv_sec = 0;
t.tv_usec = 0;
if (ioctl (info -> rfdesc, NIOCSTIME, &t) < 0)
log_fatal ("Can't set chunk timeout: %m");
#endif
/* Ask for no header... */
x = 0;
if (ioctl (info -> rfdesc, NIOCSFLAGS, &x) < 0)
log_fatal ("Can't set NIT flags on %s: %m", info -> name);
/* Set up the NIT filter program. */
/* XXX Unlike the BPF filter program, this one won't work if the
XXX IP packet is fragmented or if there are options on the IP
XXX header. */
pf.Pf_Priority = 0;
pf.Pf_FilterLen = 0;
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 6;
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
pf.Pf_Filter [pf.Pf_FilterLen++] = htons (ETHERTYPE_IP);
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT;
pf.Pf_Filter [pf.Pf_FilterLen++] = htons (IPPROTO_UDP);
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 11;
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_AND;
pf.Pf_Filter [pf.Pf_FilterLen++] = htons (0xFF);
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_CAND;
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 18;
pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
pf.Pf_Filter [pf.Pf_FilterLen++] = *libdhcp_callbacks.local_port;
/* Install the filter... */
sio.ic_cmd = NIOCSETF;
sio.ic_len = sizeof pf;
sio.ic_dp = (char *)&pf;
sio.ic_timout = INFTIM;
if (ioctl (info -> rfdesc, I_STR, &sio) < 0)
log_fatal ("Can't set NIT filter on %s: %m", info -> name);
if (!quiet_interface_discovery)
log_info ("Listening on NIT/%s%s%s",
print_hw_addr (info -> hw_address.hbuf [0],
info -> hw_address.hlen - 1,
&info -> hw_address.hbuf [1]),
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
void if_deregister_receive (info)
struct interface_info *info;
{
/* If we're using the nit API for sending and receiving,
we don't need to register this interface twice. */
close (info -> rfdesc);
info -> rfdesc = -1;
if (!quiet_interface_discovery)
log_info ("Disabling input on NIT/%s%s%s",
print_hw_addr (info -> hw_address.hbuf [0],
info -> hw_address.hlen - 1,
&info -> hw_address.hbuf [1]),
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
#endif /* USE_NIT_RECEIVE */
#ifdef USE_NIT_SEND
ssize_t send_packet (interface, packet, raw, len, from, to, hto)
struct interface_info *interface;
struct packet *packet;
struct dhcp_packet *raw;
size_t len;
struct in_addr from;
struct sockaddr_in *to;
struct hardware *hto;
{
unsigned hbufp, ibufp;
double hh [16];
double ih [1536 / sizeof (double)];
unsigned char *buf = (unsigned char *)ih;
struct sockaddr *junk;
struct strbuf ctl, data;
struct sockaddr_in foo;
int result;
if (!strcmp (interface -> name, "fallback"))
return send_fallback (interface, packet, raw,
len, from, to, hto);
if (hto == NULL && interface->anycast_mac_addr.hlen)
hto = &interface->anycast_mac_addr;
/* Start with the sockaddr struct... */
junk = (struct sockaddr *)&hh [0];
hbufp = (((unsigned char *)&junk -> sa_data [0]) -
(unsigned char *)&hh[0]);
ibufp = 0;
/* Assemble the headers... */
assemble_hw_header (interface, (unsigned char *)junk, &hbufp, hto);
assemble_udp_ip_header (interface, buf, &ibufp,
from.s_addr, to -> sin_addr.s_addr,
to -> sin_port, (unsigned char *)raw, len);
/* Copy the data into the buffer (yuk). */
memcpy (buf + ibufp, raw, len);
/* Set up the sockaddr structure... */
#if USE_SIN_LEN
junk -> sa_len = hbufp - 2; /* XXX */
#endif
junk -> sa_family = AF_UNSPEC;
/* Set up the msg_buf structure... */
ctl.buf = (char *)&hh [0];
ctl.maxlen = ctl.len = hbufp;
data.buf = (char *)&ih [0];
data.maxlen = data.len = ibufp + len;
result = putmsg (interface -> wfdesc, &ctl, &data, 0);
if (result < 0)
log_error ("send_packet: %m");
return result;
}
#endif /* USE_NIT_SEND */
#ifdef USE_NIT_RECEIVE
ssize_t receive_packet (interface, buf, len, from, hfrom)
struct interface_info *interface;
unsigned char *buf;
size_t len;
struct sockaddr_in *from;
struct hardware *hfrom;
{
int nread;
int length = 0;
int offset = 0;
unsigned char ibuf [1536];
int bufix = 0;
unsigned paylen;
length = read (interface -> rfdesc, ibuf, sizeof ibuf);
if (length <= 0)
return length;
/* Decode the physical header... */
offset = decode_hw_header (interface, ibuf, bufix, hfrom);
/* If a physical layer checksum failed (dunno of any
physical layer that supports this, but WTH), skip this
packet. */
if (offset < 0) {
return 0;
}
bufix += offset;
length -= offset;
/* Decode the IP and UDP headers... */
offset = decode_udp_ip_header (interface, ibuf, bufix,
from, length, &paylen, 1);
/* If the IP or UDP checksum was bad, skip the packet... */
if (offset < 0)
return 0;
bufix += offset;
length -= offset;
if (length < paylen)
log_fatal("Internal inconsistency at %s:%d.", MDL);
/* Copy out the data in the packet... */
memcpy(buf, &ibuf[bufix], paylen);
return paylen;
}
int can_unicast_without_arp (ip)
struct interface_info *ip;
{
return 1;
}
int can_receive_unicast_unconfigured (ip)
struct interface_info *ip;
{
return 1;
}
int supports_multiple_interfaces (ip)
struct interface_info *ip;
{
return 1;
}
void maybe_setup_fallback ()
{
isc_result_t status;
struct interface_info *fbi = (struct interface_info *)0;
if (setup_fallback (&fbi, MDL)) {
if_register_fallback (fbi);
status = omapi_register_io_object ((omapi_object_t *)fbi,
if_readsocket, 0,
fallback_discard, 0, 0);
if (status != ISC_R_SUCCESS)
log_fatal ("Can't register I/O handle for %s: %s",
fbi -> name, isc_result_totext (status));
interface_dereference (&fbi, MDL);
}
}
#endif