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Import of userspace SLIP implementation.

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bg- 2006-08-02 14:40:47 +00:00
parent 4eee7b8bf4
commit c94a70e0b3
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/*
* Copyright (c) 2001, Adam Dunkels.
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* 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.
*
* This file is part of the uIP TCP/IP stack.
*
* $Id: tunslip.c,v 1.1 2006/08/02 14:40:47 bg- Exp $
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <err.h>
int ssystem(const char *fmt, ...)
__attribute__((__format__ (__printf__, 1, 2)));
void write_to_serial(int outfd, void *inbuf, int len);
//#define PROGRESS(s) fprintf(stderr, s)
#define PROGRESS(s) do { } while (0)
struct ip {
u_int8_t ip_vhl; /* version and header length */
#define IP_V4 0x40
#define IP_V 0xf0
#define IP_HL 0x0f
u_int8_t ip_tos; /* type of service */
u_int16_t ip_len; /* total length */
u_int16_t ip_id; /* identification */
u_int16_t ip_off; /* fragment offset field */
#define IP_RF 0x8000 /* reserved fragment flag */
#define IP_DF 0x4000 /* dont fragment flag */
#define IP_MF 0x2000 /* more fragments flag */
#define IP_OFFMASK 0x1fff /* mask for fragmenting bits */
u_int8_t ip_ttl; /* time to live */
u_int8_t ip_p; /* protocol */
u_int16_t ip_sum; /* checksum */
u_int32_t ip_src, ip_dst; /* source and dest address */
u_int16_t uh_sport; /* source port */
u_int16_t uh_dport; /* destination port */
u_int16_t uh_ulen; /* udp length */
u_int16_t uh_sum; /* udp checksum */
};
int check_ip(const struct ip *ip, unsigned ip_len);
u_int16_t ip4sum(u_int16_t sum, const void *_p, u_int16_t len);
struct dhcp_msg {
u_int8_t op, htype, hlen, hops;
u_int8_t xid[4];
u_int16_t secs, flags;
u_int8_t ciaddr[4];
u_int8_t yiaddr[4];
u_int8_t siaddr[4];
u_int8_t giaddr[4];
u_int8_t chaddr[16];
#define DHCP_BASE_LEN (4*7 + 16)
u_int8_t sname[64];
u_int8_t file[128];
#define DHCP_HOLE_LEN (64 + 128)
#define DHCP_MSG_LEN (DHCP_BASE_LEN + DHCP_HOLE_LEN)
u_int8_t options[312];
};
struct dhcp_light_msg {
u_int8_t op, htype, hlen, hops;
u_int8_t xid[4];
u_int16_t secs, flags;
u_int8_t ciaddr[4];
u_int8_t yiaddr[4];
u_int8_t siaddr[4];
u_int8_t giaddr[4];
u_int8_t chaddr[16];
#define DHCP_LIGHT_MSG_LEN (4*7 + 16)
u_int8_t options[312];
};
#define DHCP_OPTION_SUBNET_MASK 1
#define DHCP_OPTION_ROUTER 3
#define DHCP_OPTION_DNS_SERVER 6
#define DHCP_OPTION_REQ_IPADDR 50
#define DHCP_OPTION_LEASE_TIME 51
#define DHCP_OPTION_MSG_TYPE 53
#define DHCP_OPTION_SERVER_ID 54
#define DHCP_OPTION_REQ_LIST 55
#define DHCP_OPTION_AGENT 82
#define DHCP_OPTION_SUBNET_SELECTION 118
#define DHCP_OPTION_END 255
/* DHCP_OPTION_AGENT, Relay Agent Information option subtypes: */
#define RAI_CIRCUIT_ID 1
#define RAI_REMOTE_ID 2
#define RAI_AGENT_ID 3
#define RAI_SUBNET_SELECTION 5
#define DHCPDISCOVER 1
#define DHCPOFFER 2
#define DHCPREQUEST 3
#define DHCPDECLINE 4
#define DHCPACK 5
#define DHCPNAK 6
#define DHCPRELEASE 7
#define BOOTP_BROADCAST 0x8000
#define BOOTPS 67
#define BOOTPC 68
#define BOOTREQUEST 1
#define BOOTREPLY 2
in_addr_t giaddr;
in_addr_t netaddr;
in_addr_t circuit_addr;
struct sockaddr_in dhaddr;
int dhsock = -1;
void
relay_dhcp_to_server(struct ip *ip, int len)
{
struct dhcp_light_msg *inm;
struct dhcp_msg m;
int n;
u_int8_t *optptr;
inm = (void*)(((u_int8_t*)ip) + 20 + 8); /* Skip over IP&UDP headers. */
if (inm->op != BOOTREQUEST) {
return;
}
inm->flags = ntohs(BOOTP_BROADCAST);
memcpy(&m, inm, DHCP_BASE_LEN);
memset(&m.sname, 0x0, DHCP_HOLE_LEN);
memcpy(&m.options, &inm->options, len - 20 - 8 - DHCP_BASE_LEN);
n = (len - 20 - 8) + DHCP_HOLE_LEN; /* +HOLE -IP&UDP headers. */
/*
* Ideally we would like to use the Relay Agent information option
* (RFC3046) together with the Link Selection sub-option (RFC3527)
* to ensure that addresses are allocated for this
* subnet. Unfortunately ISC-DHCPD does not currently implement
* RFC3527 and some other mechanism must be used. For this reason
* this implementation in addition uses the DHCP option for subnet
* selection (RFC3011) which is really not intended to be used by
* relays.
*
* Find DHCP_OPTION_END and add the new option here.
*/
optptr = &m.options[n - DHCP_BASE_LEN - DHCP_HOLE_LEN - 1];
{
*optptr++ = DHCP_OPTION_SUBNET_SELECTION; /* RFC3011 */
*optptr++ = 4;
memcpy(optptr, &netaddr, 4); optptr += 4;
n += 4 + 2;
}
{
*optptr++ = DHCP_OPTION_AGENT; /* RFC3046 */
*optptr++ = 18; /* Sum of all suboptions below! */
*optptr++ = RAI_SUBNET_SELECTION; /* RFC3527 */
*optptr++ = 4;
memcpy(optptr, &netaddr, 4); optptr += 4;
*optptr++ = RAI_CIRCUIT_ID;
*optptr++ = 4;
memcpy(optptr, &circuit_addr, 4); optptr += 4;
*optptr++ = RAI_AGENT_ID;
*optptr++ = 4;
memcpy(optptr, &giaddr, 4); optptr += 4;
n += 18 + 2; /* Sum of all suboptions + 2! */
}
/* And finally put back the END. */
*optptr++ = DHCP_OPTION_END;
m.hops++;
memcpy(m.giaddr, &giaddr, sizeof(m.giaddr));
if (n != sendto(dhsock, &m, n, 0x0/*flags*/,
(struct sockaddr *)&dhaddr, sizeof(dhaddr)))
err(1, "sendto relay failed");
}
static u_int16_t ip_id;
void
relay_dhcp_to_client(int slipfd)
{
struct dhcp_msg inm;
struct {
struct ip ip;
struct dhcp_light_msg m;
} pkt;
int n, optlen, ip_len, udp_len;
u_int8_t *p, *t, *end;
u_int16_t sum;
u_int8_t op, msg_type = 0;
struct in_addr yiaddr;
memset(&inm.options, 0x0, sizeof(inm.options));
n = recv(dhsock, &inm, sizeof(inm), 0x0/*flags*/);
if (inm.op != BOOTREPLY) {
return;
}
memcpy(&yiaddr, inm.yiaddr, sizeof(inm.yiaddr));
memcpy(&pkt.m, &inm, DHCP_BASE_LEN);
pkt.m.hops++;
memset(pkt.m.giaddr, 0x0, sizeof(pkt.m.giaddr));
/*
* Copy options we would like to send to client.
*/
memcpy(pkt.m.options, inm.options, 4); /* Magic cookie */
end = &inm.op + n;
p = inm.options + 4; /* Magic cookie */
t = pkt.m.options + 4; /* Magic cookie */
while (p < end) {
op = p[0];
switch (op) {
case DHCP_OPTION_END:
goto done;
case DHCP_OPTION_MSG_TYPE:
msg_type = p[2];
case DHCP_OPTION_SUBNET_MASK:
case DHCP_OPTION_ROUTER:
case DHCP_OPTION_LEASE_TIME:
case DHCP_OPTION_SERVER_ID: /* Copy these options */
memcpy(t, p, p[1] + 2);
t += p[1] + 2;
p += p[1] + 2;
break;
case DHCP_OPTION_DNS_SERVER: /* Only copy first server */
memcpy(t, p, 4/**/ + 2);
t += 4/**/ + 2;
p += p[1] + 2;
break;
default: /* Ignore these options */
/* printf("option type %d len %d\n", op, p[1]); */
p += p[1] + 2;
continue;
}
}
done:
if (op == DHCP_OPTION_END) {
*t++ = op; *p++;
}
optlen = t - pkt.m.options;
ip_len = 20 + 8 + DHCP_BASE_LEN + optlen;
udp_len = 8 + DHCP_BASE_LEN + optlen;
pkt.ip.ip_vhl = 0x45; /* IPv4 and hdrlen=5*4 */
pkt.ip.ip_tos = 0;
pkt.ip.ip_len = htons(ip_len);
pkt.ip.ip_id = htons(ip_id++);
pkt.ip.ip_off = 0;
pkt.ip.ip_ttl = 64;
pkt.ip.ip_p = 17; /* proto UDP */
pkt.ip.ip_sum = 0;
pkt.ip.ip_src = giaddr;
if (inm.flags & htons(BOOTP_BROADCAST)) /* check bcast bit */
pkt.ip.ip_dst = 0xffffffff; /* 255.255.255.255 */
else
pkt.ip.ip_dst = yiaddr.s_addr;
pkt.ip.uh_sport = htons(BOOTPS);
pkt.ip.uh_dport = htons(BOOTPC);
pkt.ip.uh_ulen = htons(udp_len);
pkt.ip.uh_sum = 0;
pkt.ip.ip_sum = ~htons(ip4sum(0, &pkt.ip, 20));
sum = 17 + udp_len;
sum = ip4sum(sum, &pkt.ip.ip_src, 8);
sum = ip4sum(sum, &pkt.ip.uh_sport, udp_len);
if (sum != 0xffff)
pkt.ip.uh_sum = ~htons(sum);
else
pkt.ip.uh_sum = 0xffff;
write_to_serial(slipfd, &pkt, ip_len);
if (msg_type == DHCPACK) {
printf("DHCPACK %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x IP %s\n",
pkt.m.chaddr[0], pkt.m.chaddr[1], pkt.m.chaddr[2], pkt.m.chaddr[3],
pkt.m.chaddr[4], pkt.m.chaddr[5], pkt.m.chaddr[6], pkt.m.chaddr[7],
inet_ntoa(yiaddr));
/* ssystem("arp -s %s auto pub only", inet_ntoa(yiaddr)); */
}
}
/*
* Internet checksum in host byte order.
*/
u_int16_t
ip4sum(u_int16_t sum, const void *_p, u_int16_t len)
{
u_int16_t t;
const u_int8_t *p = _p;
const u_int8_t *end = p + len;
while(p < (end-1)) {
t = (p[0] << 8) + p[1];
sum += t;
if (sum < t) sum++;
p += 2;
}
if(p < end) {
t = (p[0] << 8) + 0;
sum += t;
if (sum < t) sum++;
}
return sum;
}
int
check_ip(const struct ip *ip, unsigned ip_len)
{
u_int16_t sum, ip_hl;
/* Check IP version and length. */
if((ip->ip_vhl & IP_V) != IP_V4)
return -1;
if(ntohs(ip->ip_len) > ip_len)
return -2;
if(ntohs(ip->ip_len) < ip_len)
return -3;
/* Check IP header. */
ip_hl = 4*(ip->ip_vhl & IP_HL);
sum = ip4sum(0, ip, ip_hl);
if(sum != 0xffff && sum != 0x0)
return -4;
if(ip->ip_p == 6 || ip->ip_p == 17) { /* Check TCP or UDP header. */
u_int16_t tcp_len = ip_len - ip_hl;
/* Sum pseudoheader. */
sum = ip->ip_p + tcp_len; /* proto and len, no carry */
sum = ip4sum(sum, &ip->ip_src, 8); /* src and dst */
/* Sum TCP/UDP header and data. */
sum = ip4sum(sum, (u_int8_t*)ip + ip_hl, tcp_len);
/* Failed checksum test? */
if (sum != 0xffff && sum != 0x0) {
if (ip->ip_p == 6) { /* TCP == 6 */
return -5;
} else { /* UDP */
/* Deal with disabled UDP checksums. */
if (ip->uh_sum != 0)
return -6;
}
}
} else if (ip->ip_p == 1) { /* ICMP */
u_int16_t icmp_len = ip_len - ip_hl;
sum = ip4sum(0, (u_int8_t*)ip + ip_hl, icmp_len);
if(sum != 0xffff && sum != 0x0)
return -7;
}
return 0;
}
int
is_sensible_string(const unsigned char *s, int len)
{
int i;
for(i = 1; i < len; i++)
if (s[i] == 0 || s[i] == '\r' || s[i] == '\n' || s[i] == '\t')
continue;
else if (s[i] < ' ' || '~' < s[i])
return 0;
return 1;
}
int
ssystem(const char *fmt, ...) __attribute__((__format__ (__printf__, 1, 2)));
int
ssystem(const char *fmt, ...)
{
char cmd[128];
va_list ap;
va_start(ap, fmt);
vsnprintf(cmd, sizeof(cmd), fmt, ap);
va_end(ap);
printf("%s\n", cmd);
return system(cmd);
}
#define SLIP_END 0300
#define SLIP_ESC 0333
#define SLIP_ESC_END 0334
#define SLIP_ESC_ESC 0335
/*
* Read from serial, when we have a packet write it to tun. No output
* buffering, input buffered by stdio.
*/
void
serial_to_tun(FILE *inslip, int outfd)
{
static union {
unsigned char inbuf[2000];
struct ip iphdr;
} uip;
static int inbufptr = 0;
int ret;
unsigned char c;
read_more:
if(inbufptr >= sizeof(uip.inbuf)) {
inbufptr = 0;
}
ret = fread(&c, 1, 1, inslip);
if(ret == -1) err(1, "serial_to_tun: read");
if(ret == 0) {
clearerr(inslip);
return;
fprintf(stderr, "serial_to_tun: EOF\n");
exit(1);
}
/* fprintf(stderr, ".");*/
switch(c) {
case SLIP_END:
if(inbufptr > 0) {
/*
* Sanity checks.
*/
#define DEBUG_LINE_MARKER '\r'
int ecode;
ecode = check_ip(&uip.iphdr, inbufptr);
if(ecode < 0) {
/*
* If sensible ASCII string, print it as debug info!
*/
if (uip.inbuf[0] == DEBUG_LINE_MARKER)
fwrite(uip.inbuf + 1, inbufptr - 1, 1, stderr);
else if (is_sensible_string(uip.inbuf, inbufptr))
fwrite(uip.inbuf, inbufptr, 1, stderr);
else
fprintf(stderr,
"serial_to_tun: drop packet len=%d ecode=%d\n",
inbufptr, ecode);
inbufptr = 0;
break;
}
PROGRESS("s");
if (dhsock != -1) {
struct ip *ip = (void *)uip.inbuf;
if (ip->ip_p == 17 && ip->ip_dst == 0xffffffff /* UDP and broadcast */
&& ip->uh_sport == ntohs(BOOTPC) && ip->uh_dport == ntohs(BOOTPS)){
relay_dhcp_to_server(ip, inbufptr);
inbufptr = 0;
}
}
if(write(outfd, uip.inbuf, inbufptr) != inbufptr) err(1, "serial_to_tun: write");
inbufptr = 0;
}
break;
case SLIP_ESC:
if(fread(&c, 1, 1, inslip) != 1) {
clearerr(inslip);
/* Put ESC back and give up! */
ungetc(SLIP_ESC, inslip);
return;
}
switch(c) {
case SLIP_ESC_END:
c = SLIP_END;
break;
case SLIP_ESC_ESC:
c = SLIP_ESC;
break;
}
/* FALLTHROUGH */
default:
uip.inbuf[inbufptr++] = c;
break;
}
goto read_more;
}
unsigned char slip_buf[2000];
int slip_end, slip_begin;
void
slip_send(int fd, unsigned char c)
{
if (slip_end >= sizeof(slip_buf))
err(1, "slip_send overflow");
slip_buf[slip_end] = c;
slip_end++;
}
int
slip_empty()
{
return slip_end == 0;
}
void
slip_flushbuf(int fd)
{
int n;
if (slip_empty())
return;
n = write(fd, slip_buf + slip_begin, (slip_end - slip_begin));
if (n == -1 && errno != EAGAIN)
err(1, "slip_flushbuf write failed");
else if (n == -1)
PROGRESS("Q"); /* Outqueueis full! */
else {
slip_begin += n;
if (slip_begin == slip_end)
slip_begin = slip_end = 0;
}
}
void
write_to_serial(int outfd, void *inbuf, int len)
{
u_int8_t *p = inbuf;
int i, ecode;
struct ip *iphdr = inbuf;
/*
* Sanity checks.
*/
ecode = check_ip(inbuf, len);
if(ecode < 0) {
fprintf(stderr, "tun_to_serial: drop packet %d\n", ecode);
return;
}
if (iphdr->ip_id == 0) {
iphdr->ip_id = htons(ip_id++);
iphdr->ip_sum = 0;
iphdr->ip_sum = ~htons(ip4sum(0, iphdr, 20));
ecode = check_ip(inbuf, len);
if(ecode < 0) {
fprintf(stderr, "tun_to_serial: drop packet %d\n", ecode);
return;
}
}
/* It would be ``nice'' to send a SLIP_END here but it's not
* really necessary.
*/
/* slip_send(outfd, SLIP_END); */
for(i = 0; i < len; i++) {
switch(p[i]) {
case SLIP_END:
slip_send(outfd, SLIP_ESC);
slip_send(outfd, SLIP_ESC_END);
break;
case SLIP_ESC:
slip_send(outfd, SLIP_ESC);
slip_send(outfd, SLIP_ESC_ESC);
break;
default:
slip_send(outfd, p[i]);
break;
}
}
slip_send(outfd, SLIP_END);
PROGRESS("t");
}
/*
* Read from tun, write to slip.
*/
void
tun_to_serial(int infd, int outfd)
{
static union {
unsigned char inbuf[2000];
struct ip iphdr;
} uip;
int size;
if((size = read(infd, uip.inbuf, 2000)) == -1) err(1, "tun_to_serial: read");
write_to_serial(outfd, uip.inbuf, size);
}
#define BAUDRATE B57600
//#define BAUDRATE B38400
//#define BAUDRATE B19200
void
stty_telos(int fd)
{
struct termios tty;
speed_t speed = BAUDRATE;
int i;
if(tcflush(fd, TCIOFLUSH) == -1) err(1, "tcflush");
if(tcgetattr(fd, &tty) == -1) err(1, "tcgetattr");
cfmakeraw(&tty);
/* Nonblocking read. */
tty.c_cc[VTIME] = 0;
tty.c_cc[VMIN] = 0;
tty.c_cflag &= ~CRTSCTS;
tty.c_cflag &= ~HUPCL;
tty.c_cflag &= ~CLOCAL;
cfsetispeed(&tty, speed);
cfsetospeed(&tty, speed);
if(tcsetattr(fd, TCSAFLUSH, &tty) == -1) err(1, "tcsetattr");
#if 1
/* Nonblocking read and write. */
/* if(fcntl(fd, F_SETFL, O_NONBLOCK) == -1) err(1, "fcntl"); */
tty.c_cflag |= CLOCAL;
if(tcsetattr(fd, TCSAFLUSH, &tty) == -1) err(1, "tcsetattr");
i = TIOCM_DTR;
if(ioctl(fd, TIOCMBIS, &i) == -1) err(1, "ioctl");
#endif
usleep(10*1000); /* Wait for hardware 10ms. */
/* Flush input and output buffers. */
if(tcflush(fd, TCIOFLUSH) == -1) err(1, "tcflush");
}
#ifdef linux
#include <linux/if.h>
#include <linux/if_tun.h>
int
tun_alloc(char *dev)
{
struct ifreq ifr;
int fd, err;
if( (fd = open("/dev/net/tun", O_RDWR)) < 0 )
return -1;
memset(&ifr, 0, sizeof(ifr));
/* Flags: IFF_TUN - TUN device (no Ethernet headers)
* IFF_TAP - TAP device
*
* IFF_NO_PI - Do not provide packet information
*/
ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
if(*dev != 0)
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
if((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
close(fd);
return err;
}
strcpy(dev, ifr.ifr_name);
return fd;
}
#else
int
tun_alloc(char *dev)
{
char t[32];
strcpy(t, "/dev/");
strcat(t, dev);
return open(t, O_RDWR);
}
#endif
char tundev[32] = { "tun0" };
const char *ipaddr;
const char *netmask;
void
cleanup(int signo)
{
fprintf(stderr, "signal %d\n", signo);
#ifdef linux
#else
ssystem("sysctl net.inet.ip.forwarding=0");
/* ssystem("arp -d %s", ipaddr); */
ssystem("ifconfig %s delete", tundev);
#endif
exit(0);
}
void
ifconf(const char *tundev, const char *ipaddr, const char *netmask)
{
#ifdef linux
struct in_addr netname;
netname.s_addr = inet_addr(ipaddr) & inet_addr(netmask);
ssystem("ifconfig %s inet `hostname` up", tundev);
ssystem("route add -net %s netmask %s dev %s",
inet_ntoa(netname), netmask, tundev);
#else
ssystem("ifconfig %s inet `hostname` %s netmask %s up",
tundev, ipaddr, netmask);
ssystem("route add -net %s -netmask %s -interface %s",
ipaddr, netmask, tundev);
/* ssystem("arp -s %s auto pub only", ipaddr); */
ssystem("sysctl net.inet.ip.forwarding=1");
#endif /* !linux */
ssystem("ifconfig %s\n", tundev);
}
int
main(int argc, char **argv)
{
int tunfd, slipfd, maxfd;
int ret;
fd_set rset, wset;
FILE *inslip;
const char *siodev;
u_int16_t myport = BOOTPS, dhport = BOOTPS;
ip_id = getpid() * time(NULL);
if (argc != 3 && argc != 4)
err(1, "usage: tunslip ipaddress netmask [dhcp-server]");
ipaddr = argv[1];
netmask = argv[2];
circuit_addr = inet_addr(ipaddr);
netaddr = inet_addr(ipaddr) & inet_addr(netmask);
/*
* Set up DHCP relay agent socket and find the address of this relay
* agent.
*/
if (argc == 4) {
struct sockaddr_in myaddr;
socklen_t len;
in_addr_t a;
if (strchr(argv[3], ':') != NULL) {
dhport = atoi(strchr(argv[3], ':') + 1);
myport = dhport + 1;
*strchr(argv[3], ':') = '\0';
}
a = inet_addr(argv[3]);
if (a == -1)
err(1, "illegal dhcp-server address");
#ifndef linux
dhaddr.sin_len = sizeof(dhaddr);
#endif
dhaddr.sin_family = AF_INET;
dhaddr.sin_port = htons(dhport);
dhaddr.sin_addr.s_addr = a;
dhsock = socket(AF_INET, SOCK_DGRAM, 0);
if (dhsock < 0)
err (1, "socket");
memset(&myaddr, 0x0, sizeof(myaddr));
#ifndef linux
myaddr.sin_len = sizeof(myaddr);
#endif
myaddr.sin_family = AF_INET;
myaddr.sin_addr.s_addr = INADDR_ANY;
myaddr.sin_port = htons(myport);
if (bind(dhsock, (struct sockaddr *)&myaddr, sizeof(myaddr)) < 0)
err(1, "bind dhcp-relay");
if (connect(dhsock, (struct sockaddr *)&dhaddr, sizeof(dhaddr)) < 0)
err(1, "connect to dhcp-server");
len = sizeof(myaddr);
if (getsockname(dhsock, (struct sockaddr *)&myaddr, &len) < 0)
err(1, "getsockname dhsock");
giaddr = myaddr.sin_addr.s_addr;
/*
* Don't want connected socket.
*/
close(dhsock);
dhsock = socket(AF_INET, SOCK_DGRAM, 0);
if (dhsock < 0)
err (1, "socket");
myaddr.sin_family = AF_INET;
myaddr.sin_addr.s_addr = INADDR_ANY;
myaddr.sin_port = htons(myport);
if (bind(dhsock, (struct sockaddr *)&myaddr, sizeof(myaddr)) < 0)
err(1, "bind dhcp-relay");
fprintf(stderr, "DHCP server at %s:%d\n", argv[3], dhport);
}
{
static const char *siodevs[] = {
"/dev/ttyUSB0", "/dev/ucom0", "/dev/cuaU0"
};
int i;
for(i = 0; i < 3; i++) {
siodev = siodevs[i];
slipfd = open(siodev, O_RDWR | O_NONBLOCK);
if (slipfd != -1)
break;
}
if (slipfd == -1) err(1, "can't open slipdev");
}
fprintf(stderr, "slip started on ``%s''\n", siodev);
stty_telos(slipfd);
slip_send(slipfd, SLIP_END);
inslip = fdopen(slipfd, "r");
if(inslip == NULL) err(1, "main: fdopen");
tunfd = tun_alloc(tundev);
if(tunfd == -1) err(1, "main: open");
fprintf(stderr, "opened device ``/dev/%s''\n", tundev);
signal(SIGHUP, cleanup);
signal(SIGTERM, cleanup);
signal(SIGINT, cleanup);
ifconf(tundev, ipaddr, netmask);
while(1) {
maxfd = 0;
FD_ZERO(&rset);
FD_ZERO(&wset);
if (!slip_empty()) /* Anything to flush? */
FD_SET(slipfd, &wset);
FD_SET(slipfd, &rset); /* Read from slip ASAP! */
if(slipfd > maxfd) maxfd = slipfd;
/* We only have one packet at a time queued for slip output. */
if(slip_empty()) {
FD_SET(tunfd, &rset);
if(tunfd > maxfd) maxfd = tunfd;
if(dhsock != -1) {
FD_SET(dhsock, &rset);
if(dhsock > maxfd) maxfd = dhsock;
}
}
ret = select(maxfd + 1, &rset, &wset, NULL, NULL);
if(ret == -1)
err(1, "select");
else if(ret > 0) {
if(FD_ISSET(slipfd, &rset))
serial_to_tun(inslip, tunfd);
if(FD_ISSET(slipfd, &wset))
slip_flushbuf(slipfd);
if(slip_empty() && FD_ISSET(tunfd, &rset)) {
tun_to_serial(tunfd, slipfd);
slip_flushbuf(slipfd);
}
if(dhsock != -1 && slip_empty() && FD_ISSET(dhsock, &rset)) {
relay_dhcp_to_client(slipfd);
slip_flushbuf(slipfd);
}
} else
err(1, "select");
}
}