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#include <stddef.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include "ip_misc.h"
#define Export
/*
* Open a TCP connection to port REMOTE_PORT on host REMOTE_HOST.
* If LOCAL_HOST is not NULL, the local end of the connection is
* bound to that address. If LOCAL_PORT is not NULL, the local
* end of the connection is bound to that port.
* Hosts may be given as either a numeric IP address or as a host
* names. Ports may be given as either a decimal port number, or
* as a symbolic service name.
*
* Returns the file descriptor for the connection, or negative on
* errors.
*/
Export int
tcp_open(const char *remote_host,
const char *remote_port,
const char *local_host,
const char *local_port)
{
struct sockaddr_in server;
struct sockaddr_in local;
struct hostent * he;
int s;
#define ERRORRET(n) do { int e=errno;close(s);errno=e;return (n);} while (0)
if (remote_host == NULL || remote_port == NULL)
{
errno = EINVAL;
return -1;
}
if ((s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
return -1;
if (local_host || local_port)
{
if (get_inaddr(&local, local_host, local_port, "tcp") < 0)
ERRORRET(-1);
if (bind(s, (struct sockaddr*)&local, sizeof local) < 0)
ERRORRET(-1);
}
/* Get port */
if (get_inaddr(&server, NULL, remote_port, "tcp") < 0)
ERRORRET(-1);
/* Check for numerical IP address */
server.sin_addr.s_addr = inet_addr(remote_host);
if (server.sin_addr.s_addr != (unsigned long)-1)
{
if (connect(s, (struct sockaddr*)&server, sizeof server) < 0)
ERRORRET(-1);
return s;
}
/* Not numerical address, then it should be a host name.
* gethostbyname() it and try all the hosts addresses.
*/
if ((he = gethostbyname(remote_host)) == NULL)
ERRORRET(-1);
assert(he->h_addrtype == AF_INET);
assert(he->h_length == sizeof server.sin_addr.s_addr);
server.sin_family = he->h_addrtype;
{
char **a = he->h_addr_list;
while (*a)
{
memcpy(&server.sin_addr, *a, sizeof server.sin_addr);
if (connect(s, (struct sockaddr*)&server, sizeof server) >= 0)
return s;
a++;
}
}
ERRORRET(-1);
}
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