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#define _GNU_SOURCE
#include <sys/socket.h>
#include <dlfcn.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
static int
port_is_okay(unsigned short port)
{
char *p, *q;
long l;
p = getenv("NOPORT");
while ((p != NULL) && (*p != '\0')) {
l = strtol(p, &q, 10);
if ((q == NULL) || (q == p)) {
break;
}
if ((*q == '\0') || (*q == ',')) {
if (port == l) {
errno = ECONNREFUSED;
return -1;
}
}
p = q;
p += strspn(p, ",");
}
return 0;
}
int
connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen)
{
unsigned short port;
static int (*next_connect)(int, const struct sockaddr *, socklen_t);
if (next_connect == NULL) {
next_connect = dlsym(RTLD_NEXT, "connect");
if (next_connect == NULL) {
errno = ENOSYS;
return -1;
}
}
if (getenv("NOPORT") == NULL) {
return next_connect(sockfd, addr, addrlen);
}
switch (addr->sa_family) {
case AF_INET:
port = ntohs(((struct sockaddr_in *)addr)->sin_port);
if (port_is_okay(port) != 0) {
return -1;
}
break;
case AF_INET6:
port = ntohs(((struct sockaddr_in6 *)addr)->sin6_port);
if (port_is_okay(port) != 0) {
return -1;
}
break;
default:
break;
}
return next_connect(sockfd, addr, addrlen);
}
ssize_t
sendto(int sockfd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen)
{
unsigned short port;
static int (*next_sendto)(int, const void *, size_t, int,
const struct sockaddr *, socklen_t);
if (next_sendto == NULL) {
next_sendto = dlsym(RTLD_NEXT, "sendto");
if (next_sendto == NULL) {
errno = ENOSYS;
return -1;
}
}
if (getenv("NOPORT") == NULL) {
return next_sendto(sockfd, buf, len, flags, dest_addr, addrlen);
}
if (dest_addr != NULL) {
switch (dest_addr->sa_family) {
case AF_INET:
port = ((struct sockaddr_in *)dest_addr)->sin_port;
port = ntohs(port);
if (port_is_okay(port) != 0) {
return -1;
}
break;
case AF_INET6:
port = ((struct sockaddr_in6 *)dest_addr)->sin6_port;
port = ntohs(port);
if (port_is_okay(port) != 0) {
return -1;
}
break;
default:
break;
}
}
return next_sendto(sockfd, buf, len, flags, dest_addr, addrlen);
}
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