294 lines
8.7 KiB
C
294 lines
8.7 KiB
C
/* lpf.c
|
|
|
|
Linux packet filter code, contributed by Brian Murrel at Interlinx
|
|
Support Services in Vancouver, B.C. */
|
|
|
|
/*
|
|
* Copyright (c) 1995, 1996, 1998, 1999
|
|
* The Internet Software Consortium. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of The Internet Software Consortium nor the names
|
|
* of its contributors may be used to endorse or promote products derived
|
|
* from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
|
|
* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
|
|
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
|
|
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
|
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
|
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* This software has been written for the Internet Software Consortium
|
|
* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
|
|
* Enterprises. To learn more about the Internet Software Consortium,
|
|
* see ``http://www.vix.com/isc''. To learn more about Vixie
|
|
* Enterprises, see ``http://www.vix.com''.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char copyright[] =
|
|
"$Id: lpf.c,v 1.1.2.6 1999/02/23 22:09:55 mellon Exp $ Copyright (c) 1995, 1996, 1998, 1999 The Internet Software Consortium. All rights reserved.\n";
|
|
#endif /* not lint */
|
|
|
|
#include "dhcpd.h"
|
|
#if defined (USE_LPF_SEND) || defined (USE_LPF_RECEIVE)
|
|
#include <sys/ioctl.h>
|
|
#include <sys/uio.h>
|
|
|
|
#include <asm/types.h>
|
|
#include <linux/filter.h>
|
|
#include <linux/if_ether.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_LPF_SEND
|
|
void if_reinitialize_send (info)
|
|
struct interface_info *info;
|
|
{
|
|
}
|
|
#endif
|
|
|
|
#ifdef USE_LPF_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_lpf (info)
|
|
struct interface_info *info;
|
|
{
|
|
int sock;
|
|
char filename[50];
|
|
int b;
|
|
struct sockaddr sa;
|
|
|
|
/* Make an LPF socket. */
|
|
if ((sock = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ALL))) < 0) {
|
|
if (errno == ENOPROTOOPT || errno == EPROTONOSUPPORT ||
|
|
errno == ESOCKTNOSUPPORT || errno == EPFNOSUPPORT ||
|
|
errno == EAFNOSUPPORT)
|
|
error ("socket: %m - make sure %s %s!",
|
|
"CONFIG_PACKET and CONFIG_FILTER are defined",
|
|
"in your kernel configuration");
|
|
error("Open a socket for LPF: %m");
|
|
}
|
|
|
|
/* Bind to the interface name */
|
|
memset (&sa, 0, sizeof sa);
|
|
sa.sa_family = AF_PACKET;
|
|
strncpy (sa.sa_data, (const char *)info -> ifp, sizeof sa.sa_data);
|
|
if (bind (sock, &sa, sizeof sa)) {
|
|
if (errno == ENOPROTOOPT || errno == EPROTONOSUPPORT ||
|
|
errno == ESOCKTNOSUPPORT || errno == EPFNOSUPPORT ||
|
|
errno == EAFNOSUPPORT)
|
|
error ("socket: %m - make sure %s %s!",
|
|
"CONFIG_PACKET and CONFIG_FILTER are defined",
|
|
"in your kernel configuration");
|
|
error("Bind socket to interface: %m");
|
|
}
|
|
|
|
return sock;
|
|
}
|
|
#endif /* USE_LPF_SEND || USE_LPF_RECEIVE */
|
|
|
|
#ifdef USE_LPF_SEND
|
|
void if_register_send (info)
|
|
struct interface_info *info;
|
|
{
|
|
/* If we're using the lpf API for sending and receiving,
|
|
we don't need to register this interface twice. */
|
|
#ifndef USE_LPF_RECEIVE
|
|
info -> wfdesc = if_register_lpf (info, interface);
|
|
#else
|
|
info -> wfdesc = info -> rfdesc;
|
|
#endif
|
|
if (!quiet_interface_discovery)
|
|
note ("Sending on LPF/%s/%s%s%s",
|
|
info -> name,
|
|
print_hw_addr (info -> hw_address.htype,
|
|
info -> hw_address.hlen,
|
|
info -> hw_address.haddr),
|
|
(info -> shared_network ? "/" : ""),
|
|
(info -> shared_network ?
|
|
info -> shared_network -> name : ""));
|
|
}
|
|
#endif /* USE_LPF_SEND */
|
|
|
|
#ifdef USE_LPF_RECEIVE
|
|
/* Defined in bpf.c. We can't extern these in dhcpd.h without pulling
|
|
in bpf includes... */
|
|
extern struct sock_filter dhcp_bpf_filter [];
|
|
extern int dhcp_bpf_filter_len;
|
|
|
|
void if_register_receive (info)
|
|
struct interface_info *info;
|
|
{
|
|
struct sock_fprog p;
|
|
|
|
/* Open a LPF device and hang it on this interface... */
|
|
info -> rfdesc = if_register_lpf (info);
|
|
|
|
/* Set up the bpf filter program structure. This is defined in
|
|
bpf.c */
|
|
p.len = dhcp_bpf_filter_len;
|
|
p.filter = dhcp_bpf_filter;
|
|
|
|
/* Patch the server port into the LPF program...
|
|
XXX changes to filter program may require changes
|
|
to the insn number(s) used below! XXX */
|
|
dhcp_bpf_filter [8].k = ntohs (local_port);
|
|
|
|
if (setsockopt (info -> rfdesc, SOL_SOCKET, SO_ATTACH_FILTER, &p,
|
|
sizeof p) < 0) {
|
|
if (errno == ENOPROTOOPT || errno == EPROTONOSUPPORT ||
|
|
errno == ESOCKTNOSUPPORT || errno == EPFNOSUPPORT ||
|
|
errno == EAFNOSUPPORT)
|
|
error ("socket: %m - make sure %s %s!",
|
|
"CONFIG_PACKET and CONFIG_FILTER are defined",
|
|
"in your kernel configuration");
|
|
error ("Can't install packet filter program: %m");
|
|
}
|
|
if (!quiet_interface_discovery)
|
|
note ("Listening on LPF/%s/%s%s%s",
|
|
info -> name,
|
|
print_hw_addr (info -> hw_address.htype,
|
|
info -> hw_address.hlen,
|
|
info -> hw_address.haddr),
|
|
(info -> shared_network ? "/" : ""),
|
|
(info -> shared_network ?
|
|
info -> shared_network -> name : ""));
|
|
}
|
|
#endif /* USE_LPF_RECEIVE */
|
|
|
|
#ifdef USE_LPF_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;
|
|
{
|
|
int bufp = 0;
|
|
unsigned char buf [1500];
|
|
struct sockaddr sa;
|
|
int result;
|
|
|
|
if (!strcmp (interface -> name, "fallback"))
|
|
return send_fallback (interface, packet, raw,
|
|
len, from, to, hto);
|
|
|
|
/* Assemble the headers... */
|
|
assemble_hw_header (interface, buf, &bufp, hto);
|
|
assemble_udp_ip_header (interface, buf, &bufp, from.s_addr,
|
|
to -> sin_addr.s_addr, to -> sin_port,
|
|
(unsigned char *)raw, len);
|
|
memcpy (buf + bufp, raw, len);
|
|
|
|
/* For some reason, SOCK_PACKET sockets can't be connected,
|
|
so we have to do a sentdo every time. */
|
|
memset (&sa, 0, sizeof sa);
|
|
sa.sa_family = AF_PACKET;
|
|
strncpy (sa.sa_data,
|
|
(const char *)interface -> ifp, sizeof sa.sa_data);
|
|
|
|
result = sendto (interface -> wfdesc, buf, bufp + len, 0,
|
|
&sa, sizeof sa);
|
|
if (result < 0)
|
|
warn ("send_packet: %m");
|
|
return result;
|
|
}
|
|
#endif /* USE_LPF_SEND */
|
|
|
|
#ifdef USE_LPF_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 [1500];
|
|
int bufix = 0;
|
|
|
|
length = read (interface -> rfdesc, ibuf, sizeof ibuf);
|
|
if (length <= 0)
|
|
return length;
|
|
|
|
bufix = 0;
|
|
/* 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, (unsigned char *)0, length);
|
|
|
|
/* If the IP or UDP checksum was bad, skip the packet... */
|
|
if (offset < 0)
|
|
return 0;
|
|
|
|
bufix += offset;
|
|
length -= offset;
|
|
|
|
/* Copy out the data in the packet... */
|
|
memcpy (buf, &ibuf [bufix], length);
|
|
return length;
|
|
}
|
|
|
|
int can_unicast_without_arp ()
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
void maybe_setup_fallback ()
|
|
{
|
|
struct interface_info *fbi;
|
|
fbi = setup_fallback ();
|
|
if (fbi) {
|
|
if_register_fallback (fbi);
|
|
add_protocol ("fallback", fallback_interface -> wfdesc,
|
|
fallback_discard, fallback_interface);
|
|
}
|
|
}
|
|
#endif
|