[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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/ p9 x$ U0 M$ ]+ _, n# H正文
. J# U4 D9 \. g3 D7 b. Z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
{
char VN;
/ g" L" Z4 T2 E/ U% v- Tchar CD;
3 J7 T; C  s( W, Punsigned short Port;
unsigned long IPAddr;
! T# M  X8 g6 q0 [4 ?; Rchar other[1];
};
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struct sock4ans1
8 y! n$ I/ s- ]" _9 v( q5 H{
3 K9 N7 W8 s9 ]  X' y: x) bchar VN;
char CD;
, p0 W- u8 \$ a6 _  Y8 y};
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struct sock5req1
4 N+ I5 K! f1 z. w' P( H{
; X8 C! p9 x- d% I+ Ichar Ver;
) a) q& Y# J( L# @$ ]; b6 c+ D% mchar nMethods;
char Methods[255];
};
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struct sock5ans1
{
. _3 T( v/ l' R& Y' R6 z/ Fchar Ver;
char Method;
$ t% E1 L' D, m};
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struct sock5req2
{
char Ver;
+ {- X" }- s7 {' Mchar Cmd;
% R+ j5 A; I! Tchar Rsv;
' i' b' }$ H/ E$ C& x, e4 dchar Atyp;
. e% J2 e2 S* q# Nchar other[1];
$ W5 q% w/ c# }& B" o( u9 E1 I};
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struct sock5ans2
3 m, e, i3 O" k0 ~7 `- [6 J. i{
char Ver;
2 `& ?# w/ |7 F1 B; \( E/ V3 @. Wchar Rep;
0 J$ B' K% @0 I9 V' p( w' Rchar Rsv;
char Atyp;
char other[1];
};
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struct authreq
{
" p' o6 ]8 _% f7 l, \- q& r8 Rchar Ver;
char Ulen;
( b: b  g3 K" u3 {& @$ _: Fchar Name[255];
char PLen;
8 X" G: y2 j0 x2 jchar Pass[255];
};
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8 c" J0 o+ S* B7 b- tstruct authans
! N3 b8 A  G) P7 |9 M) h+ `6 b/ D{
char Ver;
! t* h# W& }6 {char Status;
};
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//通过Socks4方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
( Y3 g  o! m" a& A{
m_sError = _T("不能连接到代理服务器!");
/ I4 q) O. P7 z+ M- a8 t$ y/ @ClientSock.Close();
return FALSE;
}
char buff[100];
3 b5 j; Q- [; [* H8 U2 m+ w4 I  _memset(buff,0,100);
struct sock4req1 *m_proxyreq;
8 S5 L+ p& d' I" ^m_proxyreq = (struct sock4req1 *)buff;
' k- k. T7 g( o4 i% K' Z- N/ ]m_proxyreq->VN = 4;
m_proxyreq->CD = 1;
, r* c1 u+ W/ Wm_proxyreq-&gtort = ntohs(GetPort());
m_proxyreq->IPAddr = inet_addr(GetServerHostName());
ClientSock.Send(buff,9);
struct sock4ans1 *m_proxyans;
6 Z5 }& v* N: N& Bm_proxyans = (struct sock4ans1 *)buff;
+ W# S3 g7 X2 f7 X% \memset(buff,0,100);
3 Y9 @; Z# L$ |6 z) O# \8 x+ K5 gClientSock.Receive(buff,100);
if(m_proxyans->VN != 0 || m_proxyans->CD != 90)
  r' d; ^1 @8 j$ `& ?{
! N) I% s% ~4 _4 U2 Fm_sError = _T("通过代理连接主站不成功!");
# r9 M2 y( _. f) }ClientSock.Close();
return FALSE;
. q0 A& g7 O3 _8 u; s9 Y; ^) j}
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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;
m_proxyreq1 = (struct sock5req1 *)buff;
m_proxyreq1->Ver = 5;
. g8 o, J: _: I4 n/ @" ~% rm_proxyreq1->nMethods = 2;
m_proxyreq1->Methods[0] = 0;
  \8 v4 z! O7 Z1 O' D2 k, ^$ ^m_proxyreq1->Methods[1] = 2;
ClientSock.Send(buff,4);
3 `$ J. C- K/ k: w& f; [# ?" Ostruct sock5ans1 *m_proxyans1;
& Y! J1 N: E: S& a) c$ pm_proxyans1 = (struct sock5ans1 *)buff;
2 h% z5 d6 C$ o; {$ Amemset(buff,0,600);
ClientSock.Receive(buff,600);
  v+ R: e3 S6 b5 lif(m_proxyans1->Ver != 5 || (m_proxyans1->Method!=0 && m_proxyans1->Method!=2))
. [! y) J7 V3 S* n% P% x{
m_sError = _T("通过代理连接主站不成功!");
( u; w4 V9 a; B9 M: t5 zClientSock.Close();
return FALSE;
}
if(m_proxyans1->Method == 2)
{
int nUserLen = strlen(g_ProxyInfo.m_strProxyUser);
. [2 l1 N& f; j4 k6 h) x9 A% _int nPassLen = strlen(g_ProxyInfo.m_strProxyPass);
struct authreq *m_authreq;
m_authreq = (struct authreq *)buff;
! Q0 Y" q: C: }, |" B. Jm_authreq->Ver = 1;
1 s# Z4 s6 h$ t& S2 ]m_authreq->Ulen = nUserLen;
strcpy(m_authreq->Name,g_ProxyInfo.m_strProxyUser);
m_authreq-&gtLen = nPassLen;
$ }% N/ a1 n% ]9 v! {) ~strcpy(m_authreq-&gtass,g_ProxyInfo.m_strProxyPass);
# W, ~! v. d+ X. cClientSock.Send(buff,513);
) d8 }% w$ N0 J3 L& ?" \struct authans *m_authans;
m_authans = (struct authans *)buff;
5 ~& g- n! @3 Fmemset(buff,0,600);
ClientSock.Receive(buff,600);
7 D" j) [+ @, |! Sif(m_authans->Ver != 1 || m_authans->Status != 0)
+ o8 M+ q9 D3 {) H# B( X4 L+ w( y  K{
4 p& \$ G( Z. e! ]! H% nm_sError = _T("代理服务器用户验证不成功!");
ClientSock.Close();
6 {- E" G. |) t% L( h8 J; z& R" j# Jreturn FALSE;
}
! R3 S0 ?, y. h% z0 g, A/ D}
7 i1 n+ D- G( I, z$ y8 zstruct sock5req2 *m_proxyreq2;
m_proxyreq2 = (struct sock5req2 *)buff;
0 ~6 F% W" N  Lm_proxyreq2->Ver = 5;
" ]7 ]& _6 l$ \8 Tm_proxyreq2->Cmd = 1;
4 P2 f( x$ V7 s) K/ `9 z% Mm_proxyreq2->Rsv = 0;
m_proxyreq2->Atyp = 1;
unsigned long tmpLong = inet_addr(GetServerHostName());
unsigned short port = ntohs(GetPort());
memcpy(m_proxyreq2->other,&tmpLong,4);
memcpy(m_proxyreq2->other+4,&port,2);
ClientSock.Send(buff,sizeof(struct sock5req2)+5);
) {# v% s- d$ K# sstruct sock5ans2 *m_proxyans2;
: ^8 _, \# r8 e7 u, h2 m. jmemset(buff,0,600);
1 w! {& ]) e& K" z  um_proxyans2 = (struct sock5ans2 *)buff;
; K4 j9 J. Y/ o" ?; `+ |# N% ^ClientSock.Receive(buff,600);
if(m_proxyans2->Ver != 5 || m_proxyans2->Rep != 0)
5 {! e0 a& ^6 w! x3 L# o# B{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
; X5 X. p  i/ J9 l}
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9 e# \& H: V+ w( q/ q, p# Z//通过HTTP方式代理
: J( _# f* O, [3 z5 `/ Cif( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
) W! M9 ~1 [7 Z* l' w* y* ^4 U6 ]$ s{
+ Q" R+ v, S: v: w1 em_sError = _T("不能连接到代理服务器!");
" X* B( ?( `$ `2 q( r( ]ClientSock.Close();
return FALSE;
0 V' @" i. A  c; {}
char buff[600];
( p" a' H( O/ q) i3 z7 Psprintf( 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);
* C& w0 f5 ]  d3 A' |0 J, E6 hClientSock.Receive(buff,600);
if(strstr(buff, "HTTP/1.0 200 Connection established") == NULL) //连接不成功
' l5 h% |) O( X/ q/ \  }{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
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。