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#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <unistd.h>
#include <poll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
static const char *name;
typedef struct
{
int sock_fd;
const char *remote_host;
const char *remote_port;
} ThreadArg;
static void Error(const char *call)
{
fprintf(stderr, "%s:", name);
perror(call);
exit(EXIT_FAILURE);
}
static int Connect(const char *n, const char *p)
{
struct addrinfo *addr, *addr_p;
struct addrinfo hints = {0};
int status;
int sock = -1;
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
status = getaddrinfo(n, p, &hints, &addr);
if (status)
{
fprintf(stderr, "%s: %s\n", name, gai_strerror(status));
exit(EXIT_FAILURE);
}
for(addr_p = addr; addr_p && sock == -1; addr_p = addr_p->ai_next)
{
sock = socket(addr_p->ai_family,
addr_p->ai_socktype,
addr_p->ai_protocol);
if (sock != -1)
{
if (connect(sock, addr_p->ai_addr, addr_p->ai_addrlen) == -1)
{
close(sock);
sock = -1;
}
}
}
if (sock == -1)
{
fprintf(stderr, "%s: Failed to connect to %s:%s\n", name, n, p);
exit(EXIT_FAILURE);
}
return sock;
}
static int Server(int p)
{
struct sockaddr_in addr;
int sock_fd;
if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
Error("socket");
}
/* Bind port to address
*/
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=INADDR_ANY;
addr.sin_port=htons(p);
if (bind(sock_fd,(void*)&addr,sizeof(addr))==-1)
{
Error("bind");
}
if (listen(sock_fd,5)==-1)
{
Error("listen");
}
return sock_fd;
}
static void *ThreadCode(void *arg)
{
int fd;
ThreadArg *ta = arg;
struct pollfd fds[2] = {0};
int done = 0;
fd = Connect(ta->remote_host, ta->remote_port);
fds[0].fd = ta->sock_fd;
fds[0].events = POLLRDNORM;
fds[1].fd = fd;
fds[1].events = POLLRDNORM;
while(!done)
{
int f;
if (poll(fds, 2, -1) == -1)
{
Error("poll");
}
for(int f = 0; f < 2; f++)
{
if (fds[f].revents & POLLRDNORM)
{
char buff[1024];
int rd;
if ((rd = read(fds[f].fd, buff, sizeof buff)) < 1)
{
done = 1;
}
else
{
write(fds[f ^ 1].fd, buff, rd);
}
}
}
}
close(ta->sock_fd);
close(fd);
free(ta);
return NULL;
}
int main(int argc, char *argv[])
{
struct sockaddr_in addr;
char buff[1025];
int len;
socklen_t addrlen;
int sock_fd;
int connect_fd;
name=argv[0];
if (argc != 4)
{
fprintf(stderr,"%s: usage %s local_port remote_address remote_port\n",
name, name);
exit(1);
}
sock_fd = Server((short)atoi(argv[1]));
printf("%s: socket bound\n",name);
while(1)
{
pthread_t thread;
ThreadArg *arg;
printf("%s: accepting\n",name);
if ((connect_fd=accept(sock_fd,NULL,0))==-1)
{
Error("accept");
}
if (!(arg = malloc(sizeof *arg)))
{
Error("malloc");
}
arg->sock_fd = connect_fd;
arg->remote_host = argv[2];
arg->remote_port = argv[3];
pthread_create(&thread, NULL, ThreadCode, arg);
pthread_detach(thread);
}
return EXIT_SUCCESS;
}
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