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/* $OpenBSD: common.c,v 1.12 2004/05/06 20:29:04 deraadt Exp $ */
/*
* Copyright (c) 2000 Network Security Technologies, Inc. http://www.netsec.net
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/ppp_defs.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <net/bpf.h>
#include <errno.h>
#include <string.h>
#include <err.h>
#include <fcntl.h>
#include <unistd.h>
#include <sysexits.h>
#include <stdlib.h>
#include <md5.h>
#include "pppoe.h"
#define PPP_PROG "/usr/sbin/ppp"
int
runppp(int bpffd, u_int8_t *sysname)
{
int socks[2], fdm, fds, closeit;
pid_t pid;
if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) < 0)
return (-1);
fdm = socks[0];
fds = socks[1];
pid = fork();
if (pid < 0) {
close(fds);
close(fdm);
return (-1);
}
if (pid != 0) {
/* Parent */
close(fds);
return (fdm);
}
if (setsid() < 0)
_exit(99);
/* Child */
close(bpffd);
close(fdm);
closeit = 1;
if (fds == STDIN_FILENO)
closeit = 0;
else
dup2(fds, STDIN_FILENO);
if (fds == STDOUT_FILENO)
closeit = 0;
else
dup2(fds, STDOUT_FILENO);
if (fds == STDERR_FILENO)
closeit = 0;
else
dup2(fds, STDERR_FILENO);
if (closeit)
close(fds);
execlp(PPP_PROG, "ppp", "-direct", sysname, (char *)NULL);
perror("execlp");
_exit(1);
/*NOTREACHED*/
return (-1);
}
int
bpf_to_ppp(int pppfd, u_long len, u_int8_t *pkt)
{
int r;
u_int8_t hdr[2] = { PPP_ALLSTATIONS, PPP_UI };
struct iovec iov[2];
iov[0].iov_base = hdr;
iov[0].iov_len = sizeof(hdr);
iov[1].iov_base = pkt;
iov[1].iov_len = len;
r = writev(pppfd, iov, 2);
if (r < 0) {
if (errno == EINTR || errno == EPIPE || errno == ENOBUFS)
return (0);
return (-1);
}
return (1);
}
int
ppp_to_bpf(int bfd, int pppfd, struct ether_addr *myea,
struct ether_addr *rmea, u_int16_t id)
{
static u_int8_t *pktbuf = NULL;
struct pppoe_header ph;
struct iovec iov[5];
u_int16_t etype;
u_int8_t trash[2];
int r;
if (pktbuf == NULL) {
pktbuf = (u_int8_t *)malloc(PPPOE_MTU);
if (pktbuf == NULL)
return (-1);
}
iov[0].iov_base = trash;
iov[0].iov_len = 2;
iov[1].iov_base = pktbuf;
iov[1].iov_len = PPPOE_MTU;
r = readv(pppfd, iov, 2);
if (r <= 0)
return (-1);
r -= 2;
ph.vertype = PPPOE_VERTYPE(1, 1);
ph.code = PPPOE_CODE_SESSION;
ph.len = htons(r);
ph.sessionid = htons(id);
etype = htons(ETHERTYPE_PPPOE);
iov[0].iov_base = rmea; iov[0].iov_len = ETHER_ADDR_LEN;
iov[1].iov_base = myea; iov[1].iov_len = ETHER_ADDR_LEN;
iov[2].iov_base = &etype; iov[2].iov_len = sizeof(etype);
iov[3].iov_base = &ph; iov[3].iov_len = sizeof(ph);
iov[4].iov_base = pktbuf; iov[4].iov_len = r;
r = writev(bfd, iov, 5);
return (r == -1 && errno == ENOBUFS ? 0 : r);
}
int
send_padt(int bpffd, struct ether_addr *src_ea,
struct ether_addr *dst_ea, u_int16_t id)
{
struct iovec iov[4];
struct pppoe_header ph;
u_int16_t etype = htons(ETHERTYPE_PPPOEDISC);
iov[0].iov_base = dst_ea;
iov[0].iov_len = ETHER_ADDR_LEN;
iov[1].iov_base = src_ea;
iov[1].iov_len = ETHER_ADDR_LEN;
iov[2].iov_base = &etype;
iov[2].iov_len = sizeof(etype);
iov[3].iov_base = &ph;
iov[3].iov_len = sizeof(ph);
ph.vertype = PPPOE_VERTYPE(1, 1);
ph.code = PPPOE_CODE_PADT;
ph.len = 0;
ph.sessionid = htons(id);
return (writev(bpffd, iov, 4));
}
u_int32_t
cookie_bake(void)
{
MD5_CTX ctx;
unsigned char buf[40];
u_int32_t x, y;
x = arc4random();
MD5Init(&ctx);
MD5Update(&ctx, (unsigned char *)&x, sizeof(x));
MD5Final((unsigned char *)buf, &ctx);
bcopy(buf, &y, sizeof(y));
x = x ^ y;
bcopy(buf + 4, &y, sizeof(y));
x = x ^ y;
bcopy(buf + 8, &y, sizeof(y));
x = x ^ y;
bcopy(buf + 12, &y, sizeof(y));
x = x ^ y;
return (x);
}
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