/*
* (C)Copyright (C) 2012 by Darren Reed.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <net/if.h>
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include "ip_compat.h"
#include "ip_fil.h"
#include "ip_nat.h"
#include "ipf.h"
extern char *optarg;
typedef struct l4cfg {
struct l4cfg *l4_next;
struct ipnat l4_nat; /* NAT rule */
struct sockaddr_in l4_sin; /* remote socket to connect */
time_t l4_last; /* when we last connected */
int l4_alive; /* 1 = remote alive */
int l4_fd;
int l4_rw; /* 0 = reading, 1 = writing */
char *l4_rbuf; /* read buffer */
int l4_rsize; /* size of buffer */
int l4_rlen; /* how much used */
char *l4_wptr; /* next byte to write */
int l4_wlen; /* length yet to be written */
} l4cfg_t;
l4cfg_t *l4list = NULL;
char *response = NULL;
char *probe = NULL;
l4cfg_t template;
int frequency = 20;
int ctimeout = 1;
int rtimeout = 1;
size_t plen = 0;
size_t rlen = 0;
int natfd = -1;
int opts = 0;
#if defined(sun) && !defined(__svr4__) && !defined(__SVR4)
# define strerror(x) sys_errlist[x]
#endif
char *
copystr(char *dst, char *src)
{
register char *s, *t, c;
register int esc = 0;
for (s = src, t = dst; s && t && (c = *s++); )
if (esc) {
esc = 0;
switch (c)
{
case 'n' :
*t++ = '\n';
break;
case 'r' :
*t++ = '\r';
break;
case 't' :
*t++ = '\t';
break;
}
} else if (c != '\\')
*t++ = c;
else
esc = 1;
*t = '\0';
return(dst);
}
void
addnat(l4cfg_t *l4)
{
ipnat_t *ipn = &l4->l4_nat;
printf("Add NAT rule for %s/%#x,%u -> ", inet_ntoa(ipn->in_out[0]),
ipn->in_outmsk, ntohs(ipn->in_pmin));
printf("%s,%u\n", inet_ntoa(ipn->in_in[0]), ntohs(ipn->in_pnext));
if (!(opts & OPT_DONOTHING)) {
if (ioctl(natfd, SIOCADNAT, &ipn) == -1)
perror("ioctl(SIOCADNAT)");
}
}
void
delnat(l4cfg_t *l4)
{
ipnat_t *ipn = &l4->l4_nat;
printf("Remove NAT rule for %s/%#x,%u -> ",
inet_ntoa(ipn->in_out[0]), ipn->in_outmsk, ipn->in_pmin);
printf("%s,%u\n", inet_ntoa(ipn->in_in[0]), ipn->in_pnext);
if (!(opts & OPT_DONOTHING)) {
if (ioctl(natfd, SIOCRMNAT, &ipn) == -1)
perror("ioctl(SIOCRMNAT)");
}
}
void
connectl4(l4cfg_t *l4)
{
l4->l4_rw = 1;
l4->l4_rlen = 0;
l4->l4_wlen = plen;
if (!l4->l4_wlen) {
l4->l4_alive = 1;
addnat(l4);
} else
l4->l4_wptr = probe;
}
void
closel4(l4cfg_t *l4, int dead)
{
close(l4->l4_fd);
l4->l4_fd = -1;
l4->l4_rw = -1;
if (dead && l4->l4_alive) {
l4->l4_alive = 0;
delnat(l4);
}
}
void
connectfd(l4cfg_t *l4)
{
if (connect(l4->l4_fd, (struct sockaddr *)&l4->l4_sin,
sizeof(l4->l4_sin)) == -1) {
if (errno == EISCONN) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "Connected fd %d\n",
l4->l4_fd);
connectl4(l4);
return;
}
if (opts & OPT_VERBOSE)
fprintf(stderr, "Connect failed fd %d: %s\n",
l4->l4_fd, strerror(errno));
closel4(l4, 1);
return;
}
l4->l4_rw = 1;
}
void
writefd(l4cfg_t *l4)
{
char buf[80], *ptr;
int n, i, fd;
fd = l4->l4_fd;
if (l4->l4_rw == -2) {
connectfd(l4);
return;
}
n = l4->l4_wlen;
i = send(fd, l4->l4_wptr, n, 0);
if (i == 0 || i == -1) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "Send on fd %d failed: %s\n",
fd, strerror(errno));
closel4(l4, 1);
} else {
l4->l4_wptr += i;
l4->l4_wlen -= i;
if (l4->l4_wlen == 0)
l4->l4_rw = 0;
if (opts & OPT_VERBOSE)
fprintf(stderr, "Sent %d bytes to fd %d\n", i, fd);
}
}
void readfd(l4cfg_t *l4)
{
char buf[80], *ptr;
int n, i, fd;
fd = l4->l4_fd;
if (l4->l4_rw == -2) {
connectfd(l4);
return;
}
if (l4->l4_rsize) {
n = l4->l4_rsize - l4->l4_rlen;
ptr = l4->l4_rbuf + l4->l4_rlen;
} else {
n = sizeof(buf) - 1;
ptr = buf;
}
if (opts & OPT_VERBOSE)
fprintf(stderr, "Read %d bytes on fd %d to %p\n",
n, fd, ptr);
i = recv(fd, ptr, n, 0);
if (i == 0 || i == -1) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "Read error on fd %d: %s\n",
fd, (i == 0) ? "EOF" : strerror(errno));
closel4(l4, 1);
} else {
if (ptr == buf)
ptr[i] = '\0';
if (opts & OPT_VERBOSE)
fprintf(stderr, "%d: Read %d bytes [%*.*s]\n",
fd, i, i, i, ptr);
if (ptr != buf) {
l4->l4_rlen += i;
if (l4->l4_rlen >= l4->l4_rsize) {
if (!strncmp(response, l4->l4_rbuf,
l4->l4_rsize)) {
printf("%d: Good response\n",
fd);
if (!l4->l4_alive) {
l4->l4_alive = 1;
addnat(l4);
}
closel4(l4, 0);
} else {
if (opts & OPT_VERBOSE)
printf("%d: Bad response\n",
fd);
closel4(l4, 1);
}
}
} else if (!l4->l4_alive) {
l4->l4_alive = 1;
addnat(l4);
closel4(l4, 0);
}
}
}
int
runconfig(void)
{
int fd, opt, res, mfd, i;
struct timeval tv;
time_t now, now1;
fd_set rfd, wfd;
l4cfg_t *l4;
mfd = 0;
opt = 1;
now = time(NULL);
/*
* First, initiate connections that are closed, as required.
*/
for (l4 = l4list; l4; l4 = l4->l4_next) {
if ((l4->l4_last + frequency < now) && (l4->l4_fd == -1)) {
l4->l4_last = now;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd == -1)
continue;
setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt,
sizeof(opt));
#ifdef O_NONBLOCK
if ((res = fcntl(fd, F_GETFL, 0)) != -1)
fcntl(fd, F_SETFL, res | O_NONBLOCK);
#endif
if (opts & OPT_VERBOSE)
fprintf(stderr,
"Connecting to %s,%d (fd %d)...",
inet_ntoa(l4->l4_sin.sin_addr),
ntohs(l4->l4_sin.sin_port), fd);
if (connect(fd, (struct sockaddr *)&l4->l4_sin,
sizeof(l4->l4_sin)) == -1) {
if (errno != EINPROGRESS) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "failed\n");
perror("connect");
close(fd);
fd = -1;
} else {
if (opts & OPT_VERBOSE)
fprintf(stderr, "waiting\n");
l4->l4_rw = -2;
}
} else {
if (opts & OPT_VERBOSE)
fprintf(stderr, "connected\n");
connectl4(l4);
}
l4->l4_fd = fd;
}
}
/*
* Now look for fd's which we're expecting to read/write from.
*/
FD_ZERO(&rfd);
FD_ZERO(&wfd);
tv.tv_sec = MIN(rtimeout, ctimeout);
tv.tv_usec = 0;
for (l4 = l4list; l4; l4 = l4->l4_next)
if (l4->l4_rw == 0) {
if (now - l4->l4_last > rtimeout) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "%d: Read timeout\n",
l4->l4_fd);
closel4(l4, 1);
continue;
}
if (opts & OPT_VERBOSE)
fprintf(stderr, "Wait for read on fd %d\n",
l4->l4_fd);
FD_SET(l4->l4_fd, &rfd);
if (l4->l4_fd > mfd)
mfd = l4->l4_fd;
} else if ((l4->l4_rw == 1 && l4->l4_wlen) ||
l4->l4_rw == -2) {
if ((l4->l4_rw == -2) &&
(now - l4->l4_last > ctimeout)) {
if (opts & OPT_VERBOSE)
fprintf(stderr,
"%d: connect timeout\n",
l4->l4_fd);
closel4(l4);
continue;
}
if (opts & OPT_VERBOSE)
fprintf(stderr, "Wait for write on fd %d\n",
l4->l4_fd);
FD_SET(l4->l4_fd, &wfd);
if (l4->l4_fd > mfd)
mfd = l4->l4_fd;
}
if (opts & OPT_VERBOSE)
fprintf(stderr, "Select: max fd %d wait %d\n", mfd + 1,
tv.tv_sec);
i = select(mfd + 1, &rfd, &wfd, NULL, &tv);
if (i == -1) {
perror("select");
return(-1);
}
now1 = time(NULL);
for (l4 = l4list; (i > 0) && l4; l4 = l4->l4_next) {
if (l4->l4_fd < 0)
continue;
if (FD_ISSET(l4->l4_fd, &rfd)) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "Ready to read on fd %d\n",
l4->l4_fd);
readfd(l4);
i--;
}
if ((l4->l4_fd >= 0) && FD_ISSET(l4->l4_fd, &wfd)) {
if (opts & OPT_VERBOSE)
fprintf(stderr, "Ready to write on fd %d\n",
l4->l4_fd);
writefd(l4);
i--;
}
}
return(0);
}
int
gethostport(char *str, int lnum, u_32_t *ipp, u_short *portp)
{
struct servent *sp;
struct hostent *hp;
char *host, *port;
struct in_addr ip;
host = str;
port = strchr(host, ',');
if (port)
*port++ = '\0';
#ifdef HAVE_INET_ATON
if (ISDIGIT(*host) && inet_aton(host, &ip))
*ipp = ip.s_addr;
#else
if (ISDIGIT(*host))
*ipp = inet_addr(host);
#endif
else {
if (!(hp = gethostbyname(host))) {
fprintf(stderr, "%d: can't resolve hostname: %s\n",
lnum, host);
return(0);
}
*ipp = *(u_32_t *)hp->h_addr;
}
if (port) {
if (ISDIGIT(*port))
*portp = htons(atoi(port));
else {
sp = getservbyname(port, "tcp");
if (sp)
*portp = sp->s_port;
else {
fprintf(stderr, "%d: unknown service %s\n",
lnum, port);
return(0);
}
}
} else
*portp = 0;
return(1);
}
char *
mapfile(char *file, size_t *sizep)
{
struct stat sb;
caddr_t addr;
int fd;
fd = open(file, O_RDONLY);
if (fd == -1) {
perror("open(mapfile)");
return(NULL);
}
if (fstat(fd, &sb) == -1) {
perror("fstat(mapfile)");
close(fd);
return(NULL);
}
addr = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (addr == (caddr_t)-1) {
perror("mmap(mapfile)");
close(fd);
return(NULL);
}
close(fd);
*sizep = sb.st_size;
return(char *)addr;
}
int
readconfig(char *filename)
{
char c, buf[512], *s, *t, *errtxt = NULL, *line;
int num, err = 0;
ipnat_t *ipn;
l4cfg_t *l4;
FILE *fp;
fp = fopen(filename, "r");
if (!fp) {
perror("open(configfile)");
return(-1);
}
bzero((char *)&template, sizeof(template));
template.l4_fd = -1;
template.l4_rw = -1;
template.l4_sin.sin_family = AF_INET;
ipn = &template.l4_nat;
ipn->in_flags = IPN_TCP|IPN_ROUNDR;
ipn->in_redir = NAT_REDIRECT;
for (num = 1; fgets(buf, sizeof(buf), fp); num++) {
s = strchr(buf, '\n');
if (!s) {
fprintf(stderr, "%d: line too long\n", num);
fclose(fp);
return(-1);
}
*s = '\0';
/*
* lines which are comments
*/
s = strchr(buf, '#');
if (s)
*s = '\0';
/*
* Skip leading whitespace
*/
for (line = buf; (c = *line) && ISSPACE(c); line++)
;
if (!*line)
continue;
if (opts & OPT_VERBOSE)
fprintf(stderr, "Parsing: [%s]\n", line);
t = strtok(line, " \t");
if (!t)
continue;
if (!strcasecmp(t, "interface")) {
s = strtok(NULL, " \t");
if (s)
t = strtok(NULL, "\t");
if (!s || !t) {
errtxt = line;
err = -1;
break;
}
if (!strchr(t, ',')) {
fprintf(stderr,
"%d: local address,port missing\n",
num);
err = -1;
break;
}
strncpy(ipn->in_ifname, s, sizeof(ipn->in_ifname));
if (!gethostport(t, num, &ipn->in_outip,
&ipn->in_pmin)) {
errtxt = line;
err = -1;
break;
}
ipn->in_outmsk = 0xffffffff;
ipn->in_pmax = ipn->in_pmin;
if (opts & OPT_VERBOSE)
fprintf(stderr,
"Interface %s %s/%#x port %u\n",
ipn->in_ifname,
inet_ntoa(ipn->in_out[0]),
ipn->in_outmsk, ipn->in_pmin);
} else if (!strcasecmp(t, "remote")) {
if (!*ipn->in_ifname) {
fprintf(stderr,
"%d: ifname not set prior to remote\n",
num);
err = -1;
break;
}
s = strtok(NULL, " \t");
if (s)
t = strtok(NULL, "");
if (!s || !t || strcasecmp(s, "server")) {
errtxt = line;
err = -1;
break;
}
ipn->in_pnext = 0;
if (!gethostport(t, num, &ipn->in_inip,
&ipn->in_pnext)) {
errtxt = line;
err = -1;
break;
}
ipn->in_inmsk = 0xffffffff;
if (ipn->in_pnext == 0)
ipn->in_pnext = ipn->in_pmin;
l4 = (l4cfg_t *)malloc(sizeof(*l4));
if (!l4) {
fprintf(stderr, "%d: out of memory (%d)\n",
num, sizeof(*l4));
err = -1;
break;
}
bcopy((char *)&template, (char *)l4, sizeof(*l4));
l4->l4_sin.sin_addr = ipn->in_in[0];
l4->l4_sin.sin_port = ipn->in_pnext;
l4->l4_next = l4list;
l4list = l4;
} else if (!strcasecmp(t, "connect")) {
s = strtok(NULL, " \t");
if (s)
t = strtok(NULL, "\t");
if (!s || !t) {
errtxt = line;
err = -1;
break;
} else if (!strcasecmp(s, "timeout")) {
ctimeout = atoi(t);
if (opts & OPT_VERBOSE)
fprintf(stderr, "connect timeout %d\n",
ctimeout);
} else if (!strcasecmp(s, "frequency")) {
frequency = atoi(t);
if (opts & OPT_VERBOSE)
fprintf(stderr,
"connect frequency %d\n",
frequency);
} else {
errtxt = line;
err = -1;
break;
}
} else if (!strcasecmp(t, "probe")) {
s = strtok(NULL, " \t");
if (!s) {
errtxt = line;
err = -1;
break;
} else if (!strcasecmp(s, "string")) {
if (probe) {
fprintf(stderr,
"%d: probe already set\n",
num);
err = -1;
break;
}
t = strtok(NULL, "");
if (!t) {
fprintf(stderr,
"%d: No probe string\n", num);
err = -1;
break;
}
probe = malloc(strlen(t));
copystr(probe, t);
plen = strlen(probe);
if (opts & OPT_VERBOSE)
fprintf(stderr, "Probe string [%s]\n",
probe);
} else if (!strcasecmp(s, "file")) {
t = strtok(NULL, " \t");
if (!t) {
errtxt = line;
err = -1;
break;
}
if (probe) {
fprintf(stderr,
"%d: probe already set\n",
num);
err = -1;
break;
}
probe = mapfile(t, &plen);
if (opts & OPT_VERBOSE)
fprintf(stderr,
"Probe file %s len %u@%p\n",
t, plen, probe);
}
} else if (!strcasecmp(t, "response")) {
s = strtok(NULL, " \t");
if (!s) {
errtxt = line;
err = -1;
break;
} else if (!strcasecmp(s, "timeout")) {
t = strtok(NULL, " \t");
if (!t) {
errtxt = line;
err = -1;
break;
}
rtimeout = atoi(t);
if (opts & OPT_VERBOSE)
fprintf(stderr,
"response timeout %d\n",
rtimeout);
} else if (!strcasecmp(s, "string")) {
if (response) {
fprintf(stderr,
"%d: response already set\n",
num);
err = -1;
break;
}
response = strdup(strtok(NULL, ""));
rlen = strlen(response);
template.l4_rsize = rlen;
template.l4_rbuf = malloc(rlen);
if (opts & OPT_VERBOSE)
fprintf(stderr,
"Response string [%s]\n",
response);
} else if (!strcasecmp(s, "file")) {
t = strtok(NULL, " \t");
if (!t) {
errtxt = line;
err = -1;
break;
}
if (response) {
fprintf(stderr,
"%d: response already set\n",
num);
err = -1;
break;
}
response = mapfile(t, &rlen);
template.l4_rsize = rlen;
template.l4_rbuf = malloc(rlen);
if (opts & OPT_VERBOSE)
fprintf(stderr,
"Response file %s len %u@%p\n",
t, rlen, response);
}
} else {
errtxt = line;
err = -1;
break;
}
}
if (errtxt)
fprintf(stderr, "%d: syntax error at \"%s\"\n", num, errtxt);
fclose(fp);
return(err);
}
void
usage(char *prog)
{
fprintf(stderr, "Usage: %s -f <configfile>\n", prog);
exit(1);
}
int
main(int argc, char *argv[])
{
char *config = NULL;
int c;
while ((c = getopt(argc, argv, "f:nv")) != -1)
switch (c)
{
case 'f' :
config = optarg;
break;
case 'n' :
opts |= OPT_DONOTHING;
break;
case 'v' :
opts |= OPT_VERBOSE;
break;
}
if (config == NULL)
usage(argv[0]);
if (readconfig(config))
exit(1);
if (!l4list) {
fprintf(stderr, "No remote servers, exiting.");
exit(1);
}
if (!(opts & OPT_DONOTHING)) {
natfd = open(IPL_NAT, O_RDWR);
if (natfd == -1) {
perror("open(IPL_NAT)");
exit(1);
}
}
if (opts & OPT_VERBOSE)
fprintf(stderr, "Starting...\n");
while (runconfig() == 0)
;
}
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