[收藏]穿透代理服务器编程

天云上人

  作者 allfresh
  k. f  U; g% f4 U5 R% G' Q文章原始出处 www.allfresh.net/program/proxy.htm
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+ ^) z2 k1 ]' y9 ~8 \- X- A7 w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 ~) Z4 x: P! _! cstruct sock4req1
0 y4 i; f( E0 Y/ p  m7 {{
# ]9 _7 s" g, p5 j* ~& Mchar VN;
6 ?8 l7 p" ~# o( P" t5 Wchar CD;
; |7 |% }5 p1 @' V. q5 c+ K( ?5 {unsigned short Port;
7 w0 j+ j) X( V2 Funsigned long IPAddr;
char other[1];
};
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struct sock4ans1
2 }! {, {! ^& B{
char VN;
3 |0 d# i3 B1 {! H' `# G  m2 Schar CD;
5 }) U& T/ K# T( J8 \- ^- Y};
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+ v6 Q; ]5 [  u5 X; J" q$ |struct sock5req1
{
char Ver;
char nMethods;
char Methods[255];
! _% b7 y. v8 C' c5 I& s3 |" W};
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! c$ V8 ]! `. ]) Zstruct sock5ans1
; a  U$ Z$ s2 J7 H) _: ~! K- C5 y$ L, x{
3 r; F/ y, g. _8 X6 ]char Ver;
# I+ q2 s& I  _. _7 L6 ~char Method;
$ z8 @; w) b! E5 N};
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struct sock5req2
{
7 f: c' h0 H, D2 s* \char Ver;
char Cmd;
char Rsv;
: d' |( m9 X, @) q: J! y+ Ochar Atyp;
: ^1 _+ M# R& e( f. hchar other[1];
( @! z3 j: n# l+ v, C};
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; c# u. W9 j& Y. J0 Zstruct sock5ans2
{
char Ver;
char Rep;
& r. [: ^' r9 l. ]8 Uchar Rsv;
' D% q1 z# b0 S; K: p! Tchar Atyp;
: B5 A# c0 y5 ~+ x" S: H/ pchar other[1];
};
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! g% j9 A6 Q8 [$ L& B# K5 B' a. Q4 ostruct authreq
{
char Ver;
char Ulen;
char Name[255];
" R8 Q' \8 ~# b' L! rchar PLen;
: K" J1 ~7 B9 C$ X4 achar Pass[255];
};
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struct authans
- c. q0 v+ M! M  S4 b7 y{
char Ver;
char Status;
};
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//通过Socks4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;
2 l9 z  C- D5 \+ r, a& Z9 ^; ]}
7 ~2 Q2 i9 X* }' T7 Lchar buff[100];
& U9 o* p" a2 Zmemset(buff,0,100);
struct sock4req1 *m_proxyreq;
$ @7 V+ Q; b; q- R  r0 Im_proxyreq = (struct sock4req1 *)buff;
m_proxyreq->VN = 4;
3 b* O7 Y+ }. w8 @m_proxyreq->CD = 1;
m_proxyreq-&gtort = ntohs(GetPort());
m_proxyreq->IPAddr = inet_addr(GetServerHostName());
& h! J7 G( _  `5 jClientSock.Send(buff,9);
struct sock4ans1 *m_proxyans;
m_proxyans = (struct sock4ans1 *)buff;
memset(buff,0,100);
: b; }9 e  o7 u: ~; qClientSock.Receive(buff,100);
if(m_proxyans->VN != 0 || m_proxyans->CD != 90)
; \+ O' x  `7 W4 z, e{
m_sError = _T("通过代理连接主站不成功!");
) h0 }" m" X+ z+ G! i( LClientSock.Close();
, r7 e4 o7 _4 K% g) ~. Hreturn 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!");
9 U- I. S+ G! B3 o' DClientSock.Close();
6 @* P8 s( `' ?2 `) Z- Rreturn FALSE;
}
char buff[600];
( _6 @. N% x" {4 A3 q7 Kstruct sock5req1 *m_proxyreq1;
8 u2 P1 K6 ?1 Om_proxyreq1 = (struct sock5req1 *)buff;
! w* q3 n4 W. Jm_proxyreq1->Ver = 5;
m_proxyreq1->nMethods = 2;
& C. r; L9 _- K0 _3 h! e+ r+ Nm_proxyreq1->Methods[0] = 0;
m_proxyreq1->Methods[1] = 2;
ClientSock.Send(buff,4);
6 ?6 Y6 S9 C) [0 G1 Nstruct sock5ans1 *m_proxyans1;
m_proxyans1 = (struct sock5ans1 *)buff;
memset(buff,0,600);
ClientSock.Receive(buff,600);
if(m_proxyans1->Ver != 5 || (m_proxyans1->Method!=0 && m_proxyans1->Method!=2))
5 m! J1 a8 s$ L$ b' h; q0 m{
' o; s6 v& k3 l3 y+ um_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
/ |2 M* W; G( I, B}
' |% V# U8 Y# _; @5 T  Wif(m_proxyans1->Method == 2)
{
int nUserLen = strlen(g_ProxyInfo.m_strProxyUser);
  N' D& B( R0 |% d( ]+ d9 Nint nPassLen = strlen(g_ProxyInfo.m_strProxyPass);
7 I" x$ F6 w. _struct authreq *m_authreq;
2 @# v" S: y! k. \7 {m_authreq = (struct authreq *)buff;
m_authreq->Ver = 1;
) T: h) x0 e5 u; n1 i& bm_authreq->Ulen = nUserLen;
3 T- K! |  A6 g& ]$ i: tstrcpy(m_authreq->Name,g_ProxyInfo.m_strProxyUser);
m_authreq-&gtLen = nPassLen;
strcpy(m_authreq-&gtass,g_ProxyInfo.m_strProxyPass);
ClientSock.Send(buff,513);
$ N2 Z$ o3 l( G- f. G. o& zstruct authans *m_authans;
0 N  Y" S' ], Q6 zm_authans = (struct authans *)buff;
memset(buff,0,600);
1 R5 y5 G8 v$ ^& IClientSock.Receive(buff,600);
if(m_authans->Ver != 1 || m_authans->Status != 0)
" X3 ^3 w  A2 T8 N% c& t8 O7 ~{
m_sError = _T("代理服务器用户验证不成功!");
ClientSock.Close();
return FALSE;
, P1 Q1 b6 u* e! r4 Y, K. a7 p}
}
% o( s5 e) H) U  ~, `8 Rstruct sock5req2 *m_proxyreq2;
; |1 A* v: q  y* k3 d: F, Km_proxyreq2 = (struct sock5req2 *)buff;
: I5 n. n- g5 N0 S$ nm_proxyreq2->Ver = 5;
8 p- ]- f. _  |1 t5 vm_proxyreq2->Cmd = 1;
m_proxyreq2->Rsv = 0;
m_proxyreq2->Atyp = 1;
! Z( x, d, ^) m$ x. m4 Funsigned long tmpLong = inet_addr(GetServerHostName());
# z: Z+ Q9 K% Y/ H; L1 Sunsigned short port = ntohs(GetPort());
memcpy(m_proxyreq2->other,&tmpLong,4);
memcpy(m_proxyreq2->other+4,&port,2);
ClientSock.Send(buff,sizeof(struct sock5req2)+5);
* d/ V+ I7 [' Sstruct sock5ans2 *m_proxyans2;
" a9 ^+ C4 o8 O# r- Y  mmemset(buff,0,600);
3 D8 J; X! H0 U+ H1 Z% cm_proxyans2 = (struct sock5ans2 *)buff;
5 k" {( v! ?+ r) l% t7 ~$ R, qClientSock.Receive(buff,600);
if(m_proxyans2->Ver != 5 || m_proxyans2->Rep != 0)
{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
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: ?0 j$ _4 Y# F$ c
* r; j' m( [9 w/ b2 f4 Y8 }7 Q//通过HTTP方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
" D5 K- b& ^( F- A+ n) O{
m_sError = _T("不能连接到代理服务器!");
5 |( r  G0 }+ O: YClientSock.Close();
! s/ ~, a( C7 nreturn FALSE;
. N4 F+ N4 ^2 d}
, n9 ?" h2 I6 n7 \& s2 d* G- Hchar 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
/ o5 R( ~, J3 D, p! J0 J! c. O2 fmemset(buff,0,600);
$ d5 ]& L1 ?6 J; {) S5 u/ l) z/ RClientSock.Receive(buff,600);
) j) {0 P! [2 m9 y0 `7 rif(strstr(buff, "HTTP/1.0 200 Connection established") == NULL) //连接不成功
{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
2 ?, F  f0 A- I$ Q/ G" 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。