[收藏]穿透代理服务器编程

天云上人

  作者 allfresh
文章原始出处 www.allfresh.net/program/proxy.htm
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" S5 G# K4 e6 X' G正文
在网络程序设计过程中，我们经常要与各种类型的代理服务器打交道，比如在企业内部网通过代理去访问Internet网上的服务器等等，一般代理服务器支持几种常见的代理协议标准，如Socks4,Socks5,Http代理，其中Socks5需要用户验证，代理相对复杂。我在查阅RFC文档和相关资料后，特总结一些TCP协议穿透代理服务器的程序片断，希望对大家有所帮助。
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//使用到的结构
4 _, b" K( v% zstruct sock4req1
* g5 P- V1 g, b1 U* M; L) v! b. j: i{
char VN;
char CD;
unsigned short Port;
unsigned long IPAddr;
char other[1];
};
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8 i, k; M# a; ?6 I, Istruct sock4ans1
& ~$ L) R1 G/ b- ~7 i* y0 r{
" S5 W* }& Z3 W7 nchar VN;
; K' B# s% {/ @7 r& W5 Uchar CD;
};
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# r+ u  G  w+ f2 vstruct sock5req1
{
4 d4 g, V4 b, V3 n2 Jchar Ver;
char nMethods;
char Methods[255];
};
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struct sock5ans1
) n% H" a- V8 c: [; G) h* w" _6 ^3 ~{
char Ver;
char Method;
};
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struct sock5req2
+ n7 H# Y- X. y" ]1 K{
/ M/ Z' q; P' X, gchar Ver;
5 i- l( H# v" F* i: _2 zchar Cmd;
char Rsv;
char Atyp;
char other[1];
};
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( K2 o" D" }' W9 @" qstruct sock5ans2
2 C7 ^+ t" X- R4 f; |. Q* S{
char Ver;
char Rep;
7 f$ G  _1 T* `% W" O, }# X0 Bchar Rsv;
char Atyp;
char other[1];
* ~  `& t$ H! s; F+ V/ Z$ v};
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4 C6 z; H1 m# n. Y& N) T4 p7 qstruct authreq
{
7 X; L, N4 i6 V; v$ `" ~char Ver;
7 Q4 T* {, }6 H- C& |5 g" qchar Ulen;
char Name[255];
char PLen;
char Pass[255];
2 E# L# l; b- s& u0 E# m};
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& g0 b& r9 n/ s& P) S& G! V+ bstruct authans
{
char Ver;
char Status;
5 x( R7 K8 G1 W4 N* p# x. T};
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//通过Socks4方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
; n; w/ q. u0 \. x9 `; N{
m_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
6 i" H6 z- B& O9 {: Q  Q. Jreturn FALSE;
}
" v( {+ ~) q' dchar buff[100];
memset(buff,0,100);
struct sock4req1 *m_proxyreq;
m_proxyreq = (struct sock4req1 *)buff;
& s3 b4 O1 O* E, |) B( s3 \1 Vm_proxyreq->VN = 4;
m_proxyreq->CD = 1;
m_proxyreq-&gtort = ntohs(GetPort());
m_proxyreq->IPAddr = inet_addr(GetServerHostName());
3 r# c2 m" x; a; E# [ClientSock.Send(buff,9);
struct sock4ans1 *m_proxyans;
( D: q, N5 r+ T: A: wm_proxyans = (struct sock4ans1 *)buff;
0 B5 G5 n# v! e5 ~% m1 y& `memset(buff,0,100);
ClientSock.Receive(buff,100);
7 o) _( [6 @7 w# R( }if(m_proxyans->VN != 0 || m_proxyans->CD != 90)
{
" N1 L. x8 [# p" s* H- qm_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
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6 ^+ {% l/ S5 ]1 x' I: p  R, ^  j% S  m
//通过Socks5方式代理
" s0 @+ V8 N7 K. bif( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
{
m_sError = _T("不能连接到代理服务器!");
+ U/ B. Z  g- iClientSock.Close();
  O! X2 |* ?; m7 B# k2 N( z. @% r0 ]return FALSE;
}
- b0 v4 `+ d- J2 X9 W- m6 @' k/ Ochar buff[600];
struct sock5req1 *m_proxyreq1;
m_proxyreq1 = (struct sock5req1 *)buff;
m_proxyreq1->Ver = 5;
m_proxyreq1->nMethods = 2;
) A* A% J* j2 M- fm_proxyreq1->Methods[0] = 0;
m_proxyreq1->Methods[1] = 2;
" o+ d/ g4 O; ~8 x, }9 VClientSock.Send(buff,4);
" G. G/ \( Z5 E7 Estruct sock5ans1 *m_proxyans1;
m_proxyans1 = (struct sock5ans1 *)buff;
+ D# Z% P% Q5 C+ A/ ~+ Umemset(buff,0,600);
/ W# U; s+ X* h. _7 Q+ DClientSock.Receive(buff,600);
- H/ w: j( u9 M' O4 j- e) E7 Iif(m_proxyans1->Ver != 5 || (m_proxyans1->Method!=0 && m_proxyans1->Method!=2))
/ I4 A5 H/ K% x1 P{
m_sError = _T("通过代理连接主站不成功!");
( t# F9 @0 ?- r: b6 MClientSock.Close();
& |1 `. O+ U, Lreturn FALSE;
}
if(m_proxyans1->Method == 2)
{
int nUserLen = strlen(g_ProxyInfo.m_strProxyUser);
, }; i" B, C& cint nPassLen = strlen(g_ProxyInfo.m_strProxyPass);
struct authreq *m_authreq;
3 X  A1 E5 X. j2 Z* ]m_authreq = (struct authreq *)buff;
m_authreq->Ver = 1;
m_authreq->Ulen = nUserLen;
strcpy(m_authreq->Name,g_ProxyInfo.m_strProxyUser);
4 [: O9 l# C- K& ]# [' ?. ~8 Tm_authreq-&gtLen = nPassLen;
strcpy(m_authreq-&gtass,g_ProxyInfo.m_strProxyPass);
3 p6 H* K- z0 a0 ^3 r; ^" Z6 ~( PClientSock.Send(buff,513);
4 g' R+ D! v: J% C7 pstruct authans *m_authans;
m_authans = (struct authans *)buff;
memset(buff,0,600);
ClientSock.Receive(buff,600);
  d- C1 o  R! Oif(m_authans->Ver != 1 || m_authans->Status != 0)
{
; }( X6 j  l) B3 G% |9 n1 lm_sError = _T("代理服务器用户验证不成功!");
; i( ?( u5 c# Q2 ?; n; qClientSock.Close();
  ^! N6 G; d. treturn FALSE;
1 Q- V& b% l* H  W}
}
3 N0 I( k0 G" \6 K2 G2 Q( jstruct sock5req2 *m_proxyreq2;
m_proxyreq2 = (struct sock5req2 *)buff;
m_proxyreq2->Ver = 5;
m_proxyreq2->Cmd = 1;
m_proxyreq2->Rsv = 0;
m_proxyreq2->Atyp = 1;
unsigned long tmpLong = inet_addr(GetServerHostName());
unsigned short port = ntohs(GetPort());
memcpy(m_proxyreq2->other,&tmpLong,4);
8 K" a. O% ^! c, h$ [: gmemcpy(m_proxyreq2->other+4,&port,2);
ClientSock.Send(buff,sizeof(struct sock5req2)+5);
struct sock5ans2 *m_proxyans2;
! ?* u& Q3 T6 Smemset(buff,0,600);
m_proxyans2 = (struct sock5ans2 *)buff;
4 ]. n. a, d7 I' H, @+ MClientSock.Receive(buff,600);
if(m_proxyans2->Ver != 5 || m_proxyans2->Rep != 0)
, ~& M( `$ y3 p, W( `. i' Y{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
8 R# r- K7 W8 s3 c# v* z" y4 k7 Creturn FALSE;
}
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2 r2 h3 u9 S' O3 i; O$ o9 Zwwww.chin aitpower.comJZM2iofLWRmFIxU68q4I3qxHU

//通过HTTP方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
{
m_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
return FALSE;
}
char buff[600];
sprintf( buff, "%s%s:%d%s","CONNECT ",GetServerHostName(),GetPort()," HTTP/1.1\r\nUser-Agent: MyApp/0.1\r\n\r\n");
ClientSock.Send(buff,strlen(buff)); //发送请求
) ]5 h8 \, q* J: j" o  kmemset(buff,0,600);
" K/ A1 a  B8 C  D# \+ a! yClientSock.Receive(buff,600);
if(strstr(buff, "HTTP/1.0 200 Connection established") == NULL) //连接不成功
{
0 ?8 N/ h* p" R% ~1 H4 Qm_sError = _T("通过代理连接主站不成功!");
" m* Y* {/ q3 D2 q: tClientSock.Close();
2 H" c& z) w2 ?' T8 Greturn FALSE;
. Z" `8 ?5 q  E1 k8 L$ [}
我们一般先与代理服务器连通，然后向代理服务器发送代理验证的用户名和密码(如果需要,如Socks5代理)，验证成功后，再向代理服务器发送需要连接的目的地址和端口。以上代码仅用于TCP连接，如果在内部网侦听或通过UDP协议发送信息，可查阅RFC1829等文档资料。