Show tap.c syntax highlighted
/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <netdb.h>
#include <string.h>
#include <netinet/in.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#define MAXREMOTE 128
struct sockaddr_in6 localaddr;
int numremote;
struct sockaddr_in6 remoteaddr[MAXREMOTE];
int sock;
int tap;
char *tapdevice;
int getaddr(const char *hostname, struct sockaddr_in6 *in)
{
struct hostent *he;
in->sin6_port = 0;
if ((he = gethostbyname2(hostname, AF_INET6)) != NULL) {
in->sin6_family = he->h_addrtype;
memcpy(in->sin6_addr.s6_addr, he->h_addr_list[0], he->h_length);
return 0;
}
if ((he = gethostbyname2(hostname, AF_INET)) != NULL) {
in->sin6_family = AF_INET6;
memset(in->sin6_addr.s6_addr, 0, 10);
in->sin6_addr.s6_addr[10] = 0;
in->sin6_addr.s6_addr[11] = 0;
memcpy(in->sin6_addr.s6_addr + 12, he->h_addr_list[0], he->h_length);
return 0;
}
return 1;
}
void handle()
{
struct pollfd pfd[2];
pfd[0].fd = tap;
pfd[0].events = POLLIN;
pfd[1].fd = sock;
pfd[1].events = POLLIN;
while (1) {
unsigned char buf[2048];
int len;
if (poll(pfd, 2, -1) <= 0) {
perror("poll");
break;
}
if (pfd[0].revents & POLLIN) {
int i;
if ((len = read(pfd[0].fd, buf, 2048)) < 0) {
perror("read");
break;
}
for (i=0;i<numremote;i++)
if (sendto(pfd[1].fd, buf+2, len-2, 0,
&remoteaddr[i],
sizeof(remoteaddr[i])) < 0) {
perror("sendto");
break;
}
}
if (pfd[1].revents & POLLIN) {
if ((len = read(pfd[1].fd, buf+2, 2046)) < 0) {
perror("read");
break;
}
if (write(pfd[0].fd, buf, len+2) < 0) {
perror("write");
break;
}
}
}
shutdown(sock, 2);
}
int main(int argc, char *argv[])
{
int i;
if (argc < 4) {
fprintf(stderr, "syntax: %s <tapdevice> <localaddr or ::> <remotename>\n", argv[0]);
return 1;
}
tapdevice = argv[1];
if (getaddr(argv[2], &localaddr)) {
fprintf (stderr, "Can't resolve local hostname/address %s\n",
argv[2]);
return 1;
}
numremote = argc - 3;
for (i=3;i<argc;i++)
if (getaddr(argv[i], &remoteaddr[i-3])) {
fprintf(stderr,
"can't resolve hostname %s\n",
argv[i]);
return 1;
}
if ((tap = open(tapdevice, O_RDWR)) < 0) {
perror("open");
return 1;
}
if ((sock = socket(AF_INET6, SOCK_RAW, 97)) < 0) {
perror("socket");
return 1;
}
if (bind(sock, &localaddr, sizeof(localaddr)) < 0) {
perror("bind");
return 1;
}
handle();
return 0;
}
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