[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
4 t3 W0 a7 H* I& I3 D: wwwww.chin aitpower.comJZM2iofLWRmFIxU68q4I3qxHU
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
{
char VN;
char CD;
2 [' |" f' h& K5 o: r$ g: P: ~unsigned short Port;
7 d, ]6 Q6 V! V, f6 vunsigned long IPAddr;
char other[1];
};
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% |. J" v# |7 D8 m& g+ Rstruct sock4ans1
{
  _' }- v# c/ m, ]3 pchar VN;
7 ~+ n' z7 s7 N5 o' achar CD;
};
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struct sock5req1
9 ~9 S- B- m1 c8 ^8 m$ S{
char Ver;
char nMethods;
7 o/ Q' N. ]+ |# I" [char Methods[255];
};
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, W% e2 c( H6 Z8 `struct sock5ans1
) W, r, f. V7 |& g{
! F' s( a1 a  R  p% _$ A1 Q, k' H7 Gchar Ver;
char Method;
};
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/ v7 [3 ]! t/ bstruct sock5req2
{
char Ver;
char Cmd;
char Rsv;
char Atyp;
char other[1];
};
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$ g, g- ?5 f; _4 n5 N0 C" {; istruct sock5ans2
  A% {# T: ]6 A, ~5 i{
char Ver;
( Z3 A' }' r2 ^/ i+ U" J* O( _" Mchar Rep;
  N5 c. t+ d/ j+ L/ y) q& Ichar Rsv;
char Atyp;
char other[1];
};
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struct authreq
{
char Ver;
; t  Z8 f5 Z/ vchar Ulen;
/ w2 ?0 C  ?- wchar Name[255];
char PLen;
char Pass[255];
1 l' @+ }: i5 U  z  G0 l' T: T/ ?# y};
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# z* @  y+ d4 f" O# W: X+ u) p* Ostruct authans
9 B2 F: ?9 @5 t9 b: F{
char Ver;
char Status;
  ^6 h1 t+ P! H. E- b) f- L, X};
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//通过Socks4方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
  h$ H" K0 o2 Y4 \) [{
- A$ ]3 S. |8 K' n/ fm_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
return FALSE;
) J1 _0 t% L) B9 p/ L8 q) L1 R}
$ V  k8 @) L2 @) r2 ochar buff[100];
* h& r1 i" e0 y, z; Hmemset(buff,0,100);
) [) E* e2 l! A" ]struct sock4req1 *m_proxyreq;
m_proxyreq = (struct sock4req1 *)buff;
% V# f9 z# J: I$ n9 om_proxyreq->VN = 4;
5 N, T) Q9 t; D3 n! K, am_proxyreq->CD = 1;
! B- B- L1 x0 m7 v# h( m# i' Cm_proxyreq-&gtort = ntohs(GetPort());
m_proxyreq->IPAddr = inet_addr(GetServerHostName());
ClientSock.Send(buff,9);
7 s* [( W1 \+ vstruct sock4ans1 *m_proxyans;
# }6 d+ {7 m2 o( T% p9 y) Pm_proxyans = (struct sock4ans1 *)buff;
; Y  o+ Q0 s" w/ u  _( bmemset(buff,0,100);
8 v9 ~0 J; {1 v0 r9 I% X" b$ o& MClientSock.Receive(buff,100);
if(m_proxyans->VN != 0 || m_proxyans->CD != 90)
  H+ g. z$ A" A1 b3 S: A{
m_sError = _T("通过代理连接主站不成功!");
& `2 D% b3 S) t9 [ClientSock.Close();
, h) V- {( V( w. R' zreturn FALSE;
}
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//通过Socks5方式代理
  m1 j* P- h4 B6 O0 l/ Wif( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
0 U. v8 H- y% _0 K{
! j) @/ L: h* w6 v: N5 Lm_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
# G* A0 h5 ^" |! U: G7 d8 J7 creturn FALSE;
}
char buff[600];
% B5 Y: M- h7 t1 xstruct sock5req1 *m_proxyreq1;
+ n1 a/ e/ j+ t+ C3 m8 V# Gm_proxyreq1 = (struct sock5req1 *)buff;
1 g3 X! ~" g+ h6 dm_proxyreq1->Ver = 5;
" n( p' L+ a; ]" Y  z  w$ gm_proxyreq1->nMethods = 2;
m_proxyreq1->Methods[0] = 0;
m_proxyreq1->Methods[1] = 2;
0 r& }' @6 `. G2 H: ?- FClientSock.Send(buff,4);
3 ]1 ^' i7 u" |1 C% ^9 @6 W4 x, M4 dstruct sock5ans1 *m_proxyans1;
m_proxyans1 = (struct sock5ans1 *)buff;
2 S2 F" V  n5 umemset(buff,0,600);
ClientSock.Receive(buff,600);
if(m_proxyans1->Ver != 5 || (m_proxyans1->Method!=0 && m_proxyans1->Method!=2))
3 `# Z) y# g9 W; a. _- N6 h{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
& m; i% t6 ^! l2 }! Ureturn FALSE;
# t9 ]" j* @' E}
# ?4 k& C3 c* l% D# a! S9 Gif(m_proxyans1->Method == 2)
5 ?* B6 ~% ^) K5 w" @. R9 C{
int nUserLen = strlen(g_ProxyInfo.m_strProxyUser);
int nPassLen = strlen(g_ProxyInfo.m_strProxyPass);
% ?" p) L. ~2 U4 u5 m2 O0 S8 Vstruct authreq *m_authreq;
! N& h4 |2 s$ \$ Qm_authreq = (struct authreq *)buff;
m_authreq->Ver = 1;
+ g5 G6 c. N  J/ D6 U# ym_authreq->Ulen = nUserLen;
5 o) A( s% e1 k% u  }1 Istrcpy(m_authreq->Name,g_ProxyInfo.m_strProxyUser);
m_authreq-&gtLen = nPassLen;
strcpy(m_authreq-&gtass,g_ProxyInfo.m_strProxyPass);
+ a: f" u. e2 Z. b1 V; A, J+ \4 _+ d. tClientSock.Send(buff,513);
struct authans *m_authans;
7 _0 f+ ?' P  ^m_authans = (struct authans *)buff;
+ I2 E  f2 k7 C: @0 c7 w5 A" H# v8 Omemset(buff,0,600);
9 \0 m8 _( `' ^+ i1 Q7 n* @$ \& F8 LClientSock.Receive(buff,600);
: `$ j0 L5 f* V0 jif(m_authans->Ver != 1 || m_authans->Status != 0)
{
* B3 g8 g/ E9 j2 @m_sError = _T("代理服务器用户验证不成功!");
ClientSock.Close();
8 N$ j! h+ E4 F0 Y$ c/ yreturn FALSE;
}
" }( g& z3 Z* @, S# K( |# Y. m) q}
  i- V$ y* c) z* nstruct sock5req2 *m_proxyreq2;
m_proxyreq2 = (struct sock5req2 *)buff;
m_proxyreq2->Ver = 5;
m_proxyreq2->Cmd = 1;
m_proxyreq2->Rsv = 0;
' C- L( N5 d! ~5 l. F; R3 o) D" f% y* Ym_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);
5 P: R, [( o# w9 Tstruct sock5ans2 *m_proxyans2;
2 o% C9 W6 |8 v/ u/ c% Q. N0 Lmemset(buff,0,600);
9 ^+ f# H) x' X2 y( fm_proxyans2 = (struct sock5ans2 *)buff;
* X! q/ Y7 |4 n- Q* FClientSock.Receive(buff,600);
# n1 K! {3 j* ?# f( A" Rif(m_proxyans2->Ver != 5 || m_proxyans2->Rep != 0)
{
$ z% j$ g( H  o4 _m_sError = _T("通过代理连接主站不成功!");
' ~) c7 ^- S6 h$ l; H5 w. {  J  DClientSock.Close();
2 l$ i. N% C& `5 @" {+ sreturn FALSE;
, _- Q1 g( \. X) M) S  M. V}
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//通过HTTP方式代理
: ?% t8 _: f3 u/ y1 x, P( ?2 _7 Eif( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
& Y2 j! ^) R3 L( q# m1 g# U{
& K7 s; Y3 k  [! k1 [% z" }) Km_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
return FALSE;
}
; q  t3 q7 u/ a* W, Bchar 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);
; P4 o5 G' c0 a/ b& a5 `  _( ?) u4 BClientSock.Receive(buff,600);
if(strstr(buff, "HTTP/1.0 200 Connection established") == NULL) //连接不成功
& b, T" m2 T/ q3 e{
+ K& @. e, v6 c, F3 G' Mm_sError = _T("通过代理连接主站不成功!");
5 }8 L+ E0 e; f- M1 YClientSock.Close();
return FALSE;
2 B7 }9 E" r; `) T9 \, o}
; b* @7 _; M- K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。