WouterVanNifterick
I know it is not perfect
Just took a c file i found on my computer and ... a mess
/*
- $Id: simple-tcp-proxy.c,v 1.11 2006/08/03 20:30:48 wessels Exp $ */ #include <stdio.h> //#include <unistd.h> #include <stdlib.h> #include <errno.h> //#include <netdb.h> #include <string.h> #include <signal.h> #include <assert.h> //#include <syslog.h> //#include <err.h>
/*#include <sys/types.h> #include <sys/select.h> #include <sys/file.h> #include <sys/ioctl.h> #include <sys/param.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/ftp.h> #include <arpa/inet.h> #include <arpa/telnet.h> */ #define BUF_SIZE 4096
char client_hostname[64];
void cleanup(int sig) { // syslog(LOG_NOTICE, "Cleaning up..."); exit(0); }
void sigreap(int sig) { int status; pid_t p; signal(SIGCHLD, sigreap); while ((p = waitpid(-1, &status, WNOHANG)) > 0); /* no debugging in signal handler! */ }
void set_nonblock(int fd) { int fl; int x; fl = fcntl(fd, F_GETFL, 0); if (fl < 0) { syslog(LOG_ERR, "fcntl F_GETFL: FD %d: %s", fd, strerror(errno)); exit(1); } x = fcntl(fd, F_SETFL, fl | O_NONBLOCK); if (x < 0) { syslog(LOG_ERR, "fcntl F_SETFL: FD %d: %s", fd, strerror(errno)); exit(1); } }
int create_server_sock(char *addr, int port) { int addrlen, s, on = 1, x; static struct sockaddr_in client_addr;
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0)
err(1, "socket");
addrlen = sizeof(client_addr);
memset(&client_addr, '\0', addrlen);
client_addr.sin_family = AF_INET;
client_addr.sin_addr.s_addr = inet_addr(addr);
client_addr.sin_port = htons(port);
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, 4);
x = bind(s, (struct sockaddr *) &client_addr, addrlen);
if (x < 0)
err(1, "bind %s:%d", addr, port);
x = listen(s, 5);
if (x < 0)
err(1, "listen %s:%d", addr, port);
// syslog(LOG_NOTICE, "listening on %s port %d", addr, port);
return s;
}
int open_remote_host(char *host, int port) { struct sockaddr_in rem_addr; int len, s, x; struct hostent *H; int on = 1;
H = gethostbyname(host);
if (!H)
return (-2);
len = sizeof(rem_addr);
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0)
return s;
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, 4);
len = sizeof(rem_addr);
memset(&rem_addr, '\0', len);
rem_addr.sin_family = AF_INET;
memcpy(&rem_addr.sin_addr, H->h_addr, H->h_length);
rem_addr.sin_port = htons(port);
x = connect(s, (struct sockaddr *) &rem_addr, len);
if (x < 0) {
close(s);
return x;
}
set_nonblock(s);
return s;
}
int get_hinfo_from_sockaddr(struct sockaddr_in addr, int len, char *fqdn) { struct hostent *hostinfo;
hostinfo = gethostbyaddr((char *) &addr.sin_addr.s_addr, len, AF_INET);
if (!hostinfo) {
sprintf(fqdn, "%s", inet_ntoa(addr.sin_addr));
return 0;
}
if (hostinfo && fqdn)
sprintf(fqdn, "%s [%s]", hostinfo->h_name, inet_ntoa(addr.sin_addr));
return 0;
}
int wait_for_connection(int s) { static int newsock, len; static struct sockaddr_in peer;
len = sizeof(struct sockaddr);
syslog(LOG_INFO, "calling accept FD %d", s);
newsock = accept(s, (struct sockaddr *) &peer, &len);
/* dump_sockaddr (peer, len); */
if (newsock < 0) {
if (errno != EINTR) {
// syslog(LOG_NOTICE, "accept FD %d: %s", s, strerror(errno)); return -1; } } get_hinfo_from_sockaddr(peer, len, client_hostname); set_nonblock(newsock); return (newsock); }
int mywrite(int fd, char *buf, int *len) { int x = write(fd, buf, *len); if (x < 0) return x; if (x == 0) return x; if (x != *len) memmove(buf, buf+x, (*len)-x); *len -= x; return x; }
void service_client(int cfd, int sfd) { int maxfd; char *sbuf; char *cbuf; int x, n; int cbo = 0; int sbo = 0; fd_set R;
sbuf = malloc(BUF_SIZE);
cbuf = malloc(BUF_SIZE);
maxfd = cfd > sfd ? cfd : sfd;
maxfd++;
while (1) {
struct timeval to;
if (cbo) {
if (mywrite(sfd, cbuf, &cbo) < 0 && errno != EWOULDBLOCK) {
// syslog(LOG_ERR, "write %d: %s", sfd, strerror(errno)); exit(1); } } if (sbo) { if (mywrite(cfd, sbuf, &sbo) < 0 && errno != EWOULDBLOCK) { // syslog(LOG_ERR, "write %d: %s", cfd, strerror(errno)); exit(1); } } FD_ZERO(&R); if (cbo < BUF_SIZE) FD_SET(cfd, &R); if (sbo < BUF_SIZE) FD_SET(sfd, &R); to.tv_sec = 0; to.tv_usec = 1000; x = select(maxfd+1, &R, 0, 0, &to); if (x > 0) { if (FD_ISSET(cfd, &R)) { n = read(cfd, cbuf+cbo, BUF_SIZE-cbo); syslog(LOG_INFO, "read %d bytes from CLIENT (%d)", n, cfd); if (n > 0) { cbo += n; } else { close(cfd); close(sfd); // syslog(LOG_INFO, "exiting"); _exit(0); } } if (FD_ISSET(sfd, &R)) { n = read(sfd, sbuf+sbo, BUF_SIZE-sbo); syslog(LOG_INFO, "read %d bytes from SERVER (%d)", n, sfd); if (n > 0) { sbo += n; } else { close(sfd); close(cfd); syslog(LOG_INFO, "exiting"); _exit(0); } } } else if (x < 0 && errno != EINTR) { syslog(LOG_NOTICE, "select: %s", strerror(errno)); close(sfd); close(cfd); syslog(LOG_NOTICE, "exiting"); _exit(0); } } }
int main(int argc, char *argv[]) { char *localaddr = NULL; int localport = -1; char *remoteaddr = NULL; int remoteport = -1; int client = -1; int server = -1; int master_sock = -1;
if (5 != argc) {
fprintf(stderr, "usage: %s laddr lport rhost rport\n", argv[0]);
exit(1);
}
localaddr = strdup(argv[1]);
localport = atoi(argv[2]);
remoteaddr = strdup(argv[3]);
remoteport = atoi(argv[4]);
assert(localaddr);
assert(localport > 0);
assert(remoteaddr);
assert(remoteport > 0);
openlog(argv[0], LOG_PID, LOG_LOCAL4);
signal(SIGINT, cleanup);
signal(SIGCHLD, sigreap);
master_sock = create_server_sock(localaddr, localport);
for (;;) {
if ((client = wait_for_connection(master_sock)) < 0)
continue;
if ((server = open_remote_host(remoteaddr, remoteport)) < 0) {
close(client);
client = -1;
continue;
}
if (0 == fork()) {
/* child */
syslog(LOG_NOTICE, "connection from %s fd=%d", client_hostname, client);
syslog(LOG_INFO, "connected to %s:%d fd=%d", remoteaddr, remoteport, server);
close(master_sock);
service_client(client, server);
abort();
}
close(client);
client = -1;
close(server);
server = -1;
}
}
It was a bit difficult to copy/paste the code from your comment, but I found the original here: https://raw.githubusercontent.com/wessels/simple-tcp-proxy/master/simple-tcp-proxy.c
Using the latest version I get reasonable results.. I mean, you'll have to hand-edit some stuff, and this seems to be linux-oriented code, but but 90% of the code conversion job is done.
If there are specific errors that you'd like to be fixed, please specify what you think the converter could do better and I'll look into it.
