1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
/*
* smtpallow.c - ld_preload for hacking with connect() !
*
* Copyright (C) 1994,1995 Ian Jackson <ian@davenant.greenend.org.uk>
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 3,
* or (at your option) any later version.
*
* This is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this file; if not, consult the Free Software
* Foundation's website at www.fsf.org, or the GNU Project website at
* www.gnu.org.
*/
#include <syscall.h>
#include <sys/socketcall.h>
#include <netinet/in.h>
#include <string.h>
_syscall2(long,socketcall,int,call,unsigned long *,args);
int real_connect(int sockfd, const struct sockaddr *saddr, int addrlen)
{
unsigned long args[3];
args[0] = sockfd;
args[1] = (unsigned long)saddr;
args[2] = addrlen;
return socketcall(SYS_CONNECT, args);
}
int connect(int fd, const struct sockaddr *them_any, int addrlen) {
struct sockaddr_in *them= (struct sockaddr_in*)them_any;
int r,l,i;
struct sockaddr_in us;
if (addrlen == sizeof(us) &&
them->sin_family == AF_INET &&
them->sin_port == htons(25)) {
memset(&us,0,sizeof(us));
us.sin_port= 0;
us.sin_family= AF_INET;
us.sin_addr.s_addr= INADDR_ANY;
r= getsockname(fd,(struct sockaddr*)&us,&l);
if (r<0 && errno != EINVAL) return r;
if (!ntohs(us.sin_port)) {
for (i=1023; i>0; i--) {
us.sin_port= htons(i);
if (!bind(fd,(struct sockaddr*)&us,sizeof(us))) break;
if (errno != EADDRINUSE) return -1;
}
if (!i) return -1;
} else if (r<0) return r;
}
return real_connect(fd,them_any,addrlen);
}
|
