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发信人: jjk (UNIX+C+XML+?? 傻了?), 信区: Linux
标 题: datapipe小程序 guru (转寄)[转载]
发信站: 荔园晨风BBS站 (Thu Apr 25 10:25:47 2002), 转信
【 以下文字转载自 jjk 的信箱 】
【 原文由 jjk.bbs@apue.dhs.org 所发表 】
发信人: raner (毕设好无聊呀!), 信区: Linux
标 题: Re: 谁把lenx的datapipe的程序再贴一次?
发信站: BBS 水木清华站 (Wed May 6 21:14:33 1998)
【 在 scaner (S.c.a.n.e.R) 的大作中提到: 】
∶ 如题,想用的时候总是没有,呵呵.
/*
一个非常短小实用的程序, 可以非常简单的实现类似proxy的中转功能
比如, 我在mirg运行
datapipe 2222 21 159.226.23.7
以后, ftp mirg:2222就会通过mirg连接到23.7, 非常的方便
可以用datapipe层层接力, 或者用于实现简单的NAT功能, 十分好玩 :-)
The following is an interesting snippet of code I wrote recently. It
makes a data pipe between a listen port on the machine it's being run on
and a port on a remote machine. For example, running
datapipe 2222 23 your.machine.com
would create a port 2222 on the local machine that, if telnetted to, would
be the same as telnetting to port 23 on your.machine.com. This can be used
for a variety of purposes: redirect IRC connections so that identd shows
the username of the datapipe process; redirect sendmail direct connections
for the same reason; even use on a firewall machine to give access to an
internal service (ftpd, for instance). Cascaded datapipes make for
interesting traceback dilemmas. Questions and comments accepted.
Compile with:
cc -o datapipe -O datapipe.c
On boxes without strerror() (like SunOS 4.x), compile with:
cc -o datapipe -O -DSTRERROR datapipe.c
Run as:
datapipe localport remoteport remotehost
It will fork itself into the background.
/*
* Datapipe - Create a listen socket to pipe connections to another
* machine/port. 'localport' accepts connections on the machine running
* datapipe, which will connect to 'remoteport' on 'remotehost'. Fairly
* standard 500 xxxx extended errors are used if something drastic
* happens.
for a variety of purposes: redirect IRC connections so that identd shows
the username of the datapipe process; redirect sendmail direct connections
for the same reason; even use on a firewall machine to give access to an
internal service (ftpd, for instance). Cascaded datapipes make for
interesting traceback dilemmas. Questions and comments accepted.
Compile with:
cc -o datapipe -O datapipe.c
On boxes without strerror() (like SunOS 4.x), compile with:
cc -o datapipe -O -DSTRERROR datapipe.c
Run as:
datapipe localport remoteport remotehost
It will fork itself into the background.
/*
* Datapipe - Create a listen socket to pipe connections to another
* machine/port. 'localport' accepts connections on the machine running
* datapipe, which will connect to 'remoteport' on 'remotehost'. Fairly
* standard 500 xxxx extended errors are used if something drastic
* happens.
*
* (c) 1995 Todd Vierling
*
* Define STRERROR while compiling on a SunOS 4.x box
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <netdb.h>
#//include <linux/time.h>
#ifdef STRERROR
extern char *sys_errlist[];
extern int sys_nerr;
char *undef = "Undefined error";
char *strerror(error)
int error;
{
if (error > sys_nerr)
return undef;
return sys_errlist[error];
}
#endif
main(argc, argv)
int argc;
char **argv;
{
int lsock, csock, osock;
FILE *cfile;
char buf[4096];
struct sockaddr_in laddr, caddr, oaddr;
int caddrlen = sizeof(caddr);
fd_set fdsr, fdse;
struct hostent *h;
struct servent *s;
int nbyt;
unsigned long a;
unsigned short oport;
if (argc != 4) {
fprintf(stderr,"Usage: %s localport remoteport remotehost\n",argv[0]);
return 30;
}
a = inet_addr(argv[3]);
if (!(h = gethostbyname(argv[3])) &&
!(h = gethostbyaddr(&a, 4, AF_INET))) {
perror(argv[3]);
return 25;
}
oport = atol(argv[2]);
laddr.sin_port = htons((unsigned short)(atol(argv[1])));
if ((lsock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
perror("socket");
return 20;
}
laddr.sin_family = htons(AF_INET);
laddr.sin_addr.s_addr = htonl(0);
if (bind(lsock, &laddr, sizeof(laddr))) {
perror("bind");
return 20;
}
if (listen(lsock, 1)) {
perror("listen");
return 20;
}
if ((nbyt = fork()) == -1) {
perror("fork");
return 20;
}
if (nbyt > 0)
return 0;
setsid();
while ((csock = accept(lsock, &caddr, &caddrlen)) != -1) {
cfile = fdopen(csock,"r+");
if ((nbyt = fork()) == -1) {
fprintf(cfile, "500 fork: %s\n", strerror(errno));
shutdown(csock,2);
fclose(cfile);
continue;
}
if (nbyt == 0)
goto gotsock;
fclose(cfile);
while (waitpid(-1, NULL, WNOHANG) > 0);
}
return 20;
gotsock:
if ((osock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
fprintf(cfile, "500 socket: %s\n", strerror(errno));
goto quit1;
}
oaddr.sin_family = h->h_addrtype;
oaddr.sin_port = htons(oport);
memcpy(&oaddr.sin_addr, h->h_addr, h->h_length);
if (connect(osock, &oaddr, sizeof(oaddr))) {
fprintf(cfile, "500 connect: %s\n", strerror(errno));
goto quit1;
}
while (1) {
FD_ZERO(&fdsr);
FD_ZERO(&fdse);
FD_SET(csock,&fdsr);
FD_SET(csock,&fdse);
FD_SET(osock,&fdsr);
FD_SET(osock,&fdse);
if (select(20, &fdsr, NULL, &fdse, NULL) == -1) {
fprintf(cfile, "500 select: %s\n", strerror(errno));
goto quit2;
}
if (FD_ISSET(csock,&fdsr) || FD_ISSET(csock,&fdse)) {
if ((nbyt = read(csock,buf,4096)) <= 0)
goto quit2;
if ((write(osock,buf,nbyt)) <= 0)
goto quit2;
} else if (FD_ISSET(osock,&fdsr) || FD_ISSET(osock,&fdse)) {
if ((nbyt = read(osock,buf,4096)) <= 0)
goto quit2;
if ((write(csock,buf,nbyt)) <= 0)
goto quit2;
}
}
quit2:
shutdown(osock,2);
close(osock);
quit1:
fflush(cfile);
shutdown(csock,2);
quit0:
fclose(cfile);
return 0;
}
--
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※ 转寄:·UNIX编程 apue.dhs.org·[FROM: 210.39.3.50]
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