[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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3 U6 d; Z- X7 c, A0 y* ~/ N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
struct sock4req1
# `" p' M! t) m4 h/ s{
char VN;
; E3 b4 b$ P' ~; O$ r8 J4 [char CD;
unsigned short Port;
! G( {. A( S' u! nunsigned long IPAddr;
char other[1];
};
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struct sock4ans1
{
' h6 f7 Y. }9 n- J/ T3 ychar VN;
char CD;
, S- A% ?! {. [! H9 z% X* P/ B};
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struct sock5req1
{
( e% i# G! n: echar Ver;
char nMethods;
char Methods[255];
};
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struct sock5ans1
" n9 a9 p/ `. R' c1 m& a1 g0 {{
1 _! m$ Z  m. M% I  ]  Achar Ver;
char Method;
};
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6 P8 y6 m1 e' N3 e% fstruct sock5req2
{
; C# I; f; @" C/ A: k0 d5 vchar Ver;
: A1 b* }2 G2 a& a: o( ~, Ychar Cmd;
char Rsv;
& J1 ~# b% q, e' S# V  `char Atyp;
char other[1];
};
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) s) J2 W% e4 `struct sock5ans2
{
char Ver;
char Rep;
char Rsv;
' h, Z9 [: w$ u9 I0 h' Ochar Atyp;
char other[1];
6 u! B5 p& L5 n, T};
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+ ~4 S4 e, b  u/ R: G# Z: Ostruct authreq
{
! s: {  B! V" tchar Ver;
char Ulen;
char Name[255];
2 @8 F( S1 i" s9 R* q+ A% \0 Y& U+ _char PLen;
char Pass[255];
};
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0 e* G+ y  p: y- k4 {$ |struct authans
9 C' W0 X/ l+ ?4 O9 y{
char Ver;
* ]. U1 W9 v1 ]5 Q$ I' b% Gchar Status;
. v+ j+ q5 W% j8 i};
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//通过Socks4方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
! i. E4 h. v4 J3 I{
m_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
; V, `+ h2 X  W4 L+ t7 H4 dreturn FALSE;
( k( k7 o4 ^) \( c6 Y}
3 f6 U) g; u& f3 y1 @' Z- zchar buff[100];
2 E% k" ^% i- H2 @  y  T6 ~memset(buff,0,100);
struct sock4req1 *m_proxyreq;
+ F$ i+ c: z( n* D# A' |! [m_proxyreq = (struct sock4req1 *)buff;
m_proxyreq->VN = 4;
m_proxyreq->CD = 1;
m_proxyreq-&gtort = ntohs(GetPort());
4 [6 |4 L: m4 V8 T! \9 a# Rm_proxyreq->IPAddr = inet_addr(GetServerHostName());
ClientSock.Send(buff,9);
9 K" ]( I$ p* F- W3 ystruct sock4ans1 *m_proxyans;
8 n% ]& l% t! Q9 R! Zm_proxyans = (struct sock4ans1 *)buff;
memset(buff,0,100);
ClientSock.Receive(buff,100);
if(m_proxyans->VN != 0 || m_proxyans->CD != 90)
6 I- B% A2 \" N/ T{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
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//通过Socks5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];
struct sock5req1 *m_proxyreq1;
' q. N: S( N5 X3 X8 M8 }) j8 @$ ]m_proxyreq1 = (struct sock5req1 *)buff;
% ?( A2 {1 \, {m_proxyreq1->Ver = 5;
m_proxyreq1->nMethods = 2;
1 F; c5 b& K7 D5 U& I# S  g! Km_proxyreq1->Methods[0] = 0;
  ?! Y$ h# P: R* i0 f/ _+ @* lm_proxyreq1->Methods[1] = 2;
0 o# u/ G* E3 z$ p# o( UClientSock.Send(buff,4);
struct sock5ans1 *m_proxyans1;
1 h( I1 l. u: nm_proxyans1 = (struct sock5ans1 *)buff;
memset(buff,0,600);
6 S, F' F* ?# z, C+ ]# ^* }ClientSock.Receive(buff,600);
if(m_proxyans1->Ver != 5 || (m_proxyans1->Method!=0 && m_proxyans1->Method!=2))
& Y, A0 b/ n5 Z( U% c; O5 x( s{
( _' e- `7 ~/ _0 Um_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
if(m_proxyans1->Method == 2)
{
% j0 Z1 z: T# b. X1 B2 Z& a$ T1 sint nUserLen = strlen(g_ProxyInfo.m_strProxyUser);
int nPassLen = strlen(g_ProxyInfo.m_strProxyPass);
3 Y5 m. r) k% [  wstruct authreq *m_authreq;
3 R- Y- T2 F, R2 G5 U2 _1 |& E/ Rm_authreq = (struct authreq *)buff;
; C5 C2 `5 T& vm_authreq->Ver = 1;
& N  g8 [9 `" {0 um_authreq->Ulen = nUserLen;
, e) S5 C. }* Mstrcpy(m_authreq->Name,g_ProxyInfo.m_strProxyUser);
m_authreq-&gtLen = nPassLen;
: |( i% K, e$ g3 H! b3 X5 Q4 V0 Dstrcpy(m_authreq-&gtass,g_ProxyInfo.m_strProxyPass);
' d5 h4 z2 V9 F% F- v3 M$ gClientSock.Send(buff,513);
1 @1 u" e3 L0 W% K  \struct authans *m_authans;
m_authans = (struct authans *)buff;
memset(buff,0,600);
ClientSock.Receive(buff,600);
8 [4 U) i0 L* [if(m_authans->Ver != 1 || m_authans->Status != 0)
{
( _7 y$ ~, F3 ~8 D! b7 q# o* S8 fm_sError = _T("代理服务器用户验证不成功!");
$ A' _, q' d; gClientSock.Close();
+ \% Y& P) e& ]4 Ireturn FALSE;
}
}
struct sock5req2 *m_proxyreq2;
# J, S+ _0 p9 R7 @6 A5 ~m_proxyreq2 = (struct sock5req2 *)buff;
m_proxyreq2->Ver = 5;
3 k+ R6 D" S8 ?$ O) |/ Um_proxyreq2->Cmd = 1;
m_proxyreq2->Rsv = 0;
m_proxyreq2->Atyp = 1;
unsigned long tmpLong = inet_addr(GetServerHostName());
/ N9 E2 A+ w0 Dunsigned short port = ntohs(GetPort());
memcpy(m_proxyreq2->other,&tmpLong,4);
+ A$ x: n8 y: tmemcpy(m_proxyreq2->other+4,&port,2);
7 ~1 a8 h7 H: [$ m" |- R- K) ?( T+ hClientSock.Send(buff,sizeof(struct sock5req2)+5);
# r. Q/ a. X( E' w4 h- ]2 {struct sock5ans2 *m_proxyans2;
$ ~4 y/ h/ w4 \/ V0 x5 T/ _memset(buff,0,600);
5 J* ~# [: @6 x/ D, A3 }m_proxyans2 = (struct sock5ans2 *)buff;
' p6 I0 A5 K: RClientSock.Receive(buff,600);
+ S( Q% w" L+ H- @$ B+ pif(m_proxyans2->Ver != 5 || m_proxyans2->Rep != 0)
{
m_sError = _T("通过代理连接主站不成功!");
/ x' @* X! c. r5 p* o9 w) S1 FClientSock.Close();
. V/ [  U, j" V; t% e. e9 nreturn FALSE;
}
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//通过HTTP方式代理
# l4 @. b% m0 g4 Q6 Z: v# ~if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
{
m_sError = _T("不能连接到代理服务器!");
7 |' t7 A9 P. L: u( HClientSock.Close();
$ Y! O5 F! o$ X* areturn FALSE;
3 S% C. G, [; z6 g, f, A, y}
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
memset(buff,0,600);
ClientSock.Receive(buff,600);
* i  u* U4 R" _9 c2 O" @if(strstr(buff, "HTTP/1.0 200 Connection established") == NULL) //连接不成功
$ C' C9 ]; v' T- }6 m{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
6 F; }: T4 O7 f! J, M5 Zreturn FALSE;
2 R2 v# Z; S3 z$ y7 I}
/ K/ s+ w" `/ |, E+ g; n2 E" }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。