zapret/tpws/protocol.c

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C
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2021-03-04 16:30:38 +05:00
#define _GNU_SOURCE
#include "protocol.h"
#include "helpers.h"
#include <string.h>
#include <ctype.h>
#include <arpa/inet.h>
#include <string.h>
const char *http_methods[] = { "GET /","POST /","HEAD /","OPTIONS /","PUT /","DELETE /","CONNECT /","TRACE /",NULL };
bool IsHttp(const uint8_t *data, size_t len)
{
const char **method;
size_t method_len;
for (method = http_methods; *method; method++)
{
method_len = strlen(*method);
if (method_len <= len && !memcmp(data, *method, method_len))
return true;
}
return false;
}
bool HttpExtractHost(const uint8_t *data, size_t len, char *host, size_t len_host)
{
const uint8_t *p, *s, *e=data+len;
p = (uint8_t*)strncasestr((char*)data, "\nHost:", len);
if (!p) return false;
p+=6;
while(p<e && (*p==' ' || *p=='\t')) p++;
s=p;
while(s<e && (*s!='\r' && *s!='\n' && *s!=' ' && *s!='\t')) s++;
if (s>p)
{
size_t slen = s-p;
if (host && len_host)
{
if (slen>=len_host) slen=len_host-1;
for(size_t i=0;i<slen;i++) host[i]=tolower(p[i]);
host[slen]=0;
}
return true;
}
return false;
}
bool IsTLSClientHello(const uint8_t *data, size_t len)
{
return len>=6 && data[0]==0x16 && data[1]==0x03 && data[2]>=0x01 && data[2]<=0x03 && data[5]==0x01 && (ntohs(*(uint16_t*)(data+3))+5)<=len;
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}
bool TLSFindExt(const uint8_t *data, size_t len, uint16_t type, const uint8_t **ext, size_t *len_ext)
{
// +0
// u8 ContentType: Handshake
// u16 Version: TLS1.0
// u16 Length
// +5
// u8 HandshakeType: ClientHello
// u24 Length
// u16 Version
// c[32] random
// u8 SessionIDLength
// <SessionID>
// u16 CipherSuitesLength
// <CipherSuites>
// u8 CompressionMethodsLength
// <CompressionMethods>
// u16 ExtensionsLength
size_t l,ll;
l = 1+2+2+1+3+2+32;
// SessionIDLength
if (len<(l+1)) return false;
ll = data[6]<<16 | data[7]<<8 | data[8]; // HandshakeProtocol length
if (len<(ll+9)) return false;
l += data[l]+1;
// CipherSuitesLength
if (len<(l+2)) return false;
l += ntohs(*(uint16_t*)(data+l))+2;
// CompressionMethodsLength
if (len<(l+1)) return false;
l += data[l]+1;
// ExtensionsLength
if (len<(l+2)) return false;
data+=l; len-=l;
l=ntohs(*(uint16_t*)data);
data+=2; len-=2;
if (l<len) return false;
uint16_t ntype=htons(type);
while(l>=4)
{
uint16_t etype=*(uint16_t*)data;
size_t elen=ntohs(*(uint16_t*)(data+2));
data+=4; l-=4;
if (l<elen) break;
if (etype==ntype)
{
if (ext && len_ext)
{
*ext = data;
*len_ext = elen;
}
return true;
}
data+=elen; l-=elen;
}
return false;
}
bool TLSHelloExtractHost(const uint8_t *data, size_t len, char *host, size_t len_host)
{
const uint8_t *ext;
size_t elen;
if (!TLSFindExt(data,len,0,&ext,&elen)) return false;
// u16 data+0 - name list length
// u8 data+2 - server name type. 0=host_name
// u16 data+3 - server name length
if (elen<5 || ext[2]!=0) return false;
size_t slen = ntohs(*(uint16_t*)(ext+3));
ext+=5; elen-=5;
if (slen<elen) return false;
if (ext && len_host)
{
if (slen>=len_host) slen=len_host-1;
for(size_t i=0;i<slen;i++) host[i]=tolower(ext[i]);
host[slen]=0;
}
return true;
}