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nfqws,tpws: snisld split

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bol-van
2024-11-09 15:53:28 +03:00
parent 6514b6f4c3
commit f0e68527ba
7 changed files with 131 additions and 48 deletions
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82
nfq/protocol.c
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@@ -7,6 +7,23 @@
#include <arpa/inet.h>
#include <string.h>
// find N level domain
static bool FindNLD(const uint8_t *dom, size_t dlen, int level, const uint8_t **p, size_t *len)
{
int i;
const uint8_t *p1,*p2;
for (i=1,p2=dom+dlen;i<level;i++)
{
for (p2--; p2>dom && *p2!='.'; p2--);
if (p2<=dom) return false;
}
for (p1=p2-1 ; p1>dom && *p1!='.'; p1--);
if (*p1=='.') p1++;
if (p) *p = p1;
if (len) *len = p2-p1;
return true;
}
const char *http_methods[] = { "GET /","POST /","HEAD /","OPTIONS /","PUT /","DELETE /","CONNECT /","TRACE /",NULL };
const char *HttpMethod(const uint8_t *data, size_t len)
{
@@ -116,17 +133,6 @@ bool HttpExtractHost(const uint8_t *data, size_t len, char *host, size_t len_hos
{
return HttpExtractHeader(data, len, "\nHost:", host, len_host);
}
const char *HttpFind2ndLevelDomain(const char *host)
{
const char *p=NULL;
if (*host)
{
for (p = host + strlen(host)-1; p>host && *p!='.'; p--);
if (*p=='.') for (p--; p>host && *p!='.'; p--);
if (*p=='.') p++;
}
return p;
}
// DPI redirects are global redirects to another domain
bool HttpReplyLooksLikeDPIRedirect(const uint8_t *data, size_t len, const char *host)
{
@@ -157,10 +163,11 @@ bool HttpReplyLooksLikeDPIRedirect(const uint8_t *data, size_t len, const char *
// somethinkg like : censor.net
// extract 2nd level domains
const char *dhost, *drhost;
if (!FindNLD((uint8_t*)host,strlen(host),2,(const uint8_t**)&dhost,NULL) || !FindNLD((uint8_t*)redirect_host,strlen(redirect_host),2,(const uint8_t**)&drhost,NULL))
return false;
const char *dhost = HttpFind2ndLevelDomain(host);
const char *drhost = HttpFind2ndLevelDomain(redirect_host);
// compare 2nd level domains
return strcasecmp(dhost, drhost)!=0;
}
size_t HttpPos(enum httpreqpos tpos_type, size_t hpos_pos, const uint8_t *http, size_t sz)
@@ -305,15 +312,24 @@ bool TLSFindExt(const uint8_t *data, size_t len, uint16_t type, const uint8_t **
if (reclen<len) len=reclen; // correct len if it has more data than the first tls record has
return TLSFindExtInHandshake(data + 5, len - 5, type, ext, len_ext, bPartialIsOK);
}
static bool TLSAdvanceToHostInSNI(const uint8_t **ext, size_t *elen, size_t *slen)
{
// 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;
*slen = pntoh16(*ext + 3);
*ext += 5; *elen -= 5;
return *slen <= *elen;
}
static bool TLSExtractHostFromExt(const uint8_t *ext, size_t elen, char *host, size_t len_host)
{
// 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 = pntoh16(ext + 3);
ext += 5; elen -= 5;
if (slen < elen) return false;
size_t slen;
if (!TLSAdvanceToHostInSNI(&ext,&elen,&slen))
return false;
if (host && len_host)
{
if (slen >= len_host) slen = len_host - 1;
@@ -338,22 +354,46 @@ bool TLSHelloExtractHostFromHandshake(const uint8_t *data, size_t len, char *hos
if (!TLSFindExtInHandshake(data, len, 0, &ext, &elen, bPartialIsOK)) return false;
return TLSExtractHostFromExt(ext, elen, host, len_host);
}
// find N level domain in SNI
static bool TLSHelloFindNLDInSNI(const uint8_t *ext, size_t elen, int level, const uint8_t **p, size_t *len)
{
size_t slen;
return TLSAdvanceToHostInSNI(&ext,&elen,&slen) && FindNLD(ext,slen,level,p,len);
}
// find the middle of second level domain (SLD) in SNI ext : www.sobaka.ru => aka.ru
// return false if SNI ext is bad or SLD is not found
static bool TLSHelloFindMiddleOfSLDInSNI(const uint8_t *ext, size_t elen, const uint8_t **p)
{
size_t len;
if (!TLSHelloFindNLDInSNI(ext,elen,2,p,&len))
return false;
// in case of one letter SLD (x.com) we split at '.' to prevent appearance of the whole SLD
*p = (len==1) ? *p+1 : *p+len/2;
return true;
}
size_t TLSPos(enum tlspos tpos_type, size_t tpos_pos, const uint8_t *tls, size_t sz, uint8_t type)
{
size_t elen;
const uint8_t *ext;
const uint8_t *ext, *p;
switch(tpos_type)
{
case tlspos_sni:
case tlspos_sniext:
if (TLSFindExt(tls,sz,0,&ext,&elen,false))
return (tpos_type==tlspos_sni) ? ext-tls+6 : ext-tls+1;
// fall through
break;
case tlspos_snisld:
if (TLSFindExt(tls,sz,0,&ext,&elen,false))
if (TLSHelloFindMiddleOfSLDInSNI(ext,elen,&p))
return p-tls;
break;
case tlspos_pos:
return tpos_pos<sz ? tpos_pos : 0;
break;
default:
return 0;
}
return tpos_pos<sz ? tpos_pos : 0;
}