added ipv6 detection on windows for built-in resolver

[lcore.git] / dnscore.pas

diff --git a/dnscore.pas b/dnscore.pas
old mode 100755 (executable)
new mode 100644 (file)
index ef4c2f1..7cbb828
--- a/dnscore.pas
+++ b/dnscore.pas
@@ -28,7 +28,7 @@
   when a packet is received the application should put the packet in\r
   recvbuf/recvbuflen , set state.parsepacket and call state_process again\r
 \r
   when a packet is received the application should put the packet in\r
   recvbuf/recvbuflen , set state.parsepacket and call state_process again\r
 \r

-  once the app gets action_done it can determine sucess or failure in the\r
+  once the app gets action_done it can determine success or failure in the\r

   following ways.\r
 \r
   on failure state.resultstr will be an empty string and state.resultbin will\r
   following ways.\r
 \r
   on failure state.resultstr will be an empty string and state.resultbin will\r


@@ -60,7 +60,7 @@ unit dnscore;
 \r
 interface\r
 \r
 \r
 interface\r
 \r

-uses binipstuff,classes,pgtypes;\r
+uses binipstuff,classes,pgtypes,lcorernd;\r

 \r
 var usewindns : boolean = {$ifdef win32}true{$else}false{$endif};\r
 {hint to users of this unit that they should use windows dns instead.\r
 \r
 var usewindns : boolean = {$ifdef win32}true{$else}false{$endif};\r
 {hint to users of this unit that they should use windows dns instead.\r


@@ -82,6 +82,11 @@ can be set by apps as desired
 }\r
 var useaf:integer = useaf_default;\r
 \r
 }\r
 var useaf:integer = useaf_default;\r
 \r

+{\r
+(temporarily) use a different nameserver, regardless of the dnsserverlist\r
+}\r
+var overridednsserver:ansistring;\r
+\r

 const\r
   maxnamelength=127;\r
   maxnamefieldlen=63;\r
 const\r
   maxnamelength=127;\r
   maxnamefieldlen=63;\r


@@ -93,12 +98,14 @@ const
   querytype_a=1;\r
   querytype_cname=5;\r
   querytype_aaaa=28;\r
   querytype_a=1;\r
   querytype_cname=5;\r
   querytype_aaaa=28;\r

+  querytype_a6=38;\r

   querytype_ptr=12;\r
   querytype_ns=2;\r
   querytype_soa=6;\r
   querytype_mx=15;\r
   querytype_ptr=12;\r
   querytype_ns=2;\r
   querytype_soa=6;\r
   querytype_mx=15;\r

-\r
-  maxrecursion=10;\r
+  querytype_txt=16;\r
+  querytype_spf=99;\r
+  maxrecursion=50;\r

   maxrrofakind=20;\r
 \r
   retryafter=300000; //microseconds must be less than one second;\r
   maxrrofakind=20;\r
 \r
   retryafter=300000; //microseconds must be less than one second;\r


@@ -118,16 +125,16 @@ type
   tdnsstate=record\r
     id:word;\r
     recursioncount:integer;\r
   tdnsstate=record\r
     id:word;\r
     recursioncount:integer;\r

-    queryname:string;\r
+    queryname:ansistring;\r

     requesttype:word;\r
     parsepacket:boolean;\r
     requesttype:word;\r
     parsepacket:boolean;\r

-    resultstr:string;\r
+    resultstr:ansistring;\r

     resultbin:tbinip;\r
     resultlist:tbiniplist;\r
     resultaction:integer;\r
     numrr1:array[0..3] of integer;\r
     numrr2:integer;\r
     resultbin:tbinip;\r
     resultlist:tbiniplist;\r
     resultaction:integer;\r
     numrr1:array[0..3] of integer;\r
     numrr2:integer;\r

-    rrdata:string;\r
+    rrdata:ansistring;\r

     sendpacketlen:integer;\r
     sendpacket:tdnspacket;\r
     recvpacketlen:integer;\r
     sendpacketlen:integer;\r
     sendpacket:tdnspacket;\r
     recvpacketlen:integer;\r


@@ -158,29 +165,25 @@ type
 //function buildrequest(const name:string;var packet:tdnspacket;requesttype:word):integer;\r
 \r
 //returns the DNS name used to reverse look up an IP, such as 4.3.2.1.in-addr.arpa for 1.2.3.4\r
 //function buildrequest(const name:string;var packet:tdnspacket;requesttype:word):integer;\r
 \r
 //returns the DNS name used to reverse look up an IP, such as 4.3.2.1.in-addr.arpa for 1.2.3.4\r

-function makereversename(const binip:tbinip):string;\r
+function makereversename(const binip:tbinip):ansistring;\r

 \r
 \r

-procedure setstate_request_init(const name:string;var state:tdnsstate);\r
+procedure setstate_request_init(const name:ansistring;var state:tdnsstate);\r

 \r
 //set up state for a foward lookup. A family value of AF_INET6 will give only\r
 \r
 //set up state for a foward lookup. A family value of AF_INET6 will give only\r

-//ipv6 results. Any other value will give ipv4 results in preference and ipv6\r
-//results if ipv4 results are not available;\r
-procedure setstate_forward(const name:string;var state:tdnsstate;family:integer);\r
+//ipv6 results. Any other value will give only ipv4 results\r
+procedure setstate_forward(const name:ansistring;var state:tdnsstate;family:integer);\r

 \r
 procedure setstate_reverse(const binip:tbinip;var state:tdnsstate);\r
 procedure setstate_failure(var state:tdnsstate);\r
 //procedure setstate_return(const rrp:trrpointer;len:integer;var state:tdnsstate);\r
 \r
 \r
 procedure setstate_reverse(const binip:tbinip;var state:tdnsstate);\r
 procedure setstate_failure(var state:tdnsstate);\r
 //procedure setstate_return(const rrp:trrpointer;len:integer;var state:tdnsstate);\r
 \r

+//for custom raw lookups such as TXT, as desired by the user\r
+procedure setstate_custom(const name:ansistring; requesttype:integer; var state:tdnsstate);\r

 \r
 procedure state_process(var state:tdnsstate);\r
 \r
 //function decodename(const packet:tdnspacket;len,start,recursion:integer;var numread:integer):string;\r
 \r
 \r
 procedure state_process(var state:tdnsstate);\r
 \r
 //function decodename(const packet:tdnspacket;len,start,recursion:integer;var numread:integer):string;\r
 \r

-//presumablly this is exported to allow more secure random functions\r
-//to be substituted?\r
-var randomfunction:function:integer;\r
-\r
-\r

 procedure populatednsserverlist;\r
 procedure cleardnsservercache;\r
 \r
 procedure populatednsserverlist;\r
 procedure cleardnsservercache;\r
 \r


@@ -188,36 +191,70 @@ var
   dnsserverlist : tstringlist;\r
 //  currentdnsserverno : integer;\r
 \r
   dnsserverlist : tstringlist;\r
 //  currentdnsserverno : integer;\r
 \r

-function getcurrentsystemnameserver(var id:integer) :string;\r
+\r
+//getcurrentsystemnameserver returns the nameserver the app should use and sets\r
+//id to the id of that nameserver. id should later be used to report how laggy\r
+//the servers response was and if it was timed out.\r
+function getcurrentsystemnameserver(var id:integer) :ansistring;\r
+procedure reportlag(id:integer;lag:integer); //lag should be in microseconds and should be -1 to report a timeout\r

 \r
 //var\r
 //  unixnameservercache:string;\r
 { $endif}\r
 \r
 \r
 \r
 //var\r
 //  unixnameservercache:string;\r
 { $endif}\r
 \r
 \r

-procedure reportlag(id:integer;lag:integer); //lag should be in microseconds and should be -1 to report a timeout\r
+{$ifdef ipv6}\r
+function getv6localips:tbiniplist;\r
+procedure initpreferredmode;\r
+\r
+var\r
+  preferredmodeinited:boolean;\r
+\r
+{$endif}\r
+\r

 var\r
 var\r

-  failurereason:string;\r
+  failurereason:ansistring;\r
+\r
+function getquerytype(s:ansistring):integer;\r

 \r
 implementation\r
 \r
 uses\r
   {$ifdef win32}\r
 \r
 implementation\r
 \r
 uses\r
   {$ifdef win32}\r

-    windows,\r
+    windows,winsock,\r

   {$endif}\r
 \r
   sysutils;\r
 \r
   {$endif}\r
 \r
   sysutils;\r
 \r

-function buildrequest(const name:string;var packet:tdnspacket;requesttype:word):integer;\r
+\r
+\r
+function getquerytype(s:ansistring):integer;\r
+begin\r
+  s := uppercase(s);\r
+  result := 0;\r
+  if (s = 'A') then result := querytype_a else\r
+  if (s = 'CNAME') then result := querytype_cname else\r
+  if (s = 'AAAA') then result := querytype_aaaa else\r
+  if (s = 'PTR') then result := querytype_ptr else\r
+  if (s = 'NS') then result := querytype_ns else\r
+  if (s = 'MX') then result := querytype_mx else\r
+  if (s = 'A6') then result := querytype_a6 else\r
+  if (s = 'TXT') then result := querytype_txt else\r
+  if (s = 'SOA') then result := querytype_soa else\r
+  if (s = 'SPF') then result := querytype_spf;\r
+end;\r
+\r
+function buildrequest(const name:ansistring;var packet:tdnspacket;requesttype:word):integer;\r

 var\r
   a,b:integer;\r
 var\r
   a,b:integer;\r

-  s:string;\r
+  s:ansistring;\r

   arr:array[0..sizeof(packet)-1] of byte absolute packet;\r
 begin\r
  { writeln('buildrequest: name: ',name);}\r
   result := 0;\r
   fillchar(packet,sizeof(packet),0);\r
   arr:array[0..sizeof(packet)-1] of byte absolute packet;\r
 begin\r
  { writeln('buildrequest: name: ',name);}\r
   result := 0;\r
   fillchar(packet,sizeof(packet),0);\r

-  if assigned(randomfunction) then packet.id := (randomfunction and $ffff) else packet.id := random(65536);\r
+  packet.id := randominteger($10000);\r
+\r

   packet.flags := htons($0100);\r
   packet.rrcount[0] := htons($0001);\r
 \r
   packet.flags := htons($0100);\r
   packet.rrcount[0] := htons($0001);\r
 \r


@@ -252,9 +289,9 @@ begin
   arr[result-4] := requesttype shr 8;\r
 end;\r
 \r
   arr[result-4] := requesttype shr 8;\r
 end;\r
 \r

-function makereversename(const binip:tbinip):string;\r
+function makereversename(const binip:tbinip):ansistring;\r

 var\r
 var\r

-  name:string;\r
+  name:ansistring;\r

   a,b:integer;\r
 begin\r
   name := '';\r
   a,b:integer;\r
 begin\r
   name := '';\r


@@ -286,10 +323,10 @@ doesnt read beyond len.
 empty result + non null failurereason: failure\r
 empty result + null failurereason: internal use\r
 }\r
 empty result + non null failurereason: failure\r
 empty result + null failurereason: internal use\r
 }\r

-function decodename(const packet:tdnspacket;len,start,recursion:integer;var numread:integer):string;\r
+function decodename(const packet:tdnspacket;len,start,recursion:integer;var numread:integer):ansistring;\r

 var\r
   arr:array[0..sizeof(packet)-1] of byte absolute packet;\r
 var\r
   arr:array[0..sizeof(packet)-1] of byte absolute packet;\r

-  s:string;\r
+  s:ansistring;\r

   a,b:integer;\r
 begin\r
   numread := 0;\r
   a,b:integer;\r
 begin\r
   numread := 0;\r


@@ -330,7 +367,7 @@ begin
           failurereason := 'decoding name: got out of range2';\r
           exit;\r
         end;\r
           failurereason := 'decoding name: got out of range2';\r
           exit;\r
         end;\r

-        result := result + char(arr[a]);\r
+        result := result + ansichar(arr[a]);\r

       end;\r
       inc(numread,b+1);\r
 \r
       end;\r
       inc(numread,b+1);\r
 \r


@@ -348,6 +385,14 @@ end;
 \r
 {==============================================================================}\r
 \r
 \r
 {==============================================================================}\r
 \r

+function getrawfromrr(const rrp:trrpointer;len:integer):ansistring;\r
+begin\r
+  setlength(result,htons(trr(rrp.p^).datalen));\r
+  uniquestring(result);\r
+  move(trr(rrp.p^).data,result[1],length(result));\r
+end;\r
+\r
+\r

 function getipfromrr(const rrp:trrpointer;len:integer):tbinip;\r
 begin\r
   fillchar(result,sizeof(result),0);\r
 function getipfromrr(const rrp:trrpointer;len:integer):tbinip;\r
 begin\r
   fillchar(result,sizeof(result),0);\r


@@ -379,6 +424,16 @@ begin
     querytype_a{$ifdef ipv6},querytype_aaaa{$endif}: begin\r
       state.resultbin := getipfromrr(rrp,len);\r
     end;\r
     querytype_a{$ifdef ipv6},querytype_aaaa{$endif}: begin\r
       state.resultbin := getipfromrr(rrp,len);\r
     end;\r

+    querytype_txt:begin\r
+      {TXT returns a raw string}\r
+      state.resultstr := copy(getrawfromrr(rrp,len),2,9999);\r
+      fillchar(state.resultbin,sizeof(state.resultbin),0);\r
+    end;\r
+    querytype_mx:begin\r
+      {MX is a name after a 16 bits word}\r
+      state.resultstr := decodename(state.recvpacket,state.recvpacketlen,taddrint(rrp.p)-taddrint(@state.recvpacket)+12,0,a);\r
+      fillchar(state.resultbin,sizeof(state.resultbin),0);\r
+    end;\r

   else\r
     {other reply types (PTR, MX) return a hostname}\r
     state.resultstr := decodename(state.recvpacket,state.recvpacketlen,taddrint(rrp.p)-taddrint(@state.recvpacket)+10,0,a);\r
   else\r
     {other reply types (PTR, MX) return a hostname}\r
     state.resultstr := decodename(state.recvpacket,state.recvpacketlen,taddrint(rrp.p)-taddrint(@state.recvpacket)+10,0,a);\r


@@ -386,7 +441,7 @@ begin
   end;\r
 end;\r
 \r
   end;\r
 end;\r
 \r

-procedure setstate_request_init(const name:string;var state:tdnsstate);\r
+procedure setstate_request_init(const name:ansistring;var state:tdnsstate);\r

 begin\r
   {destroy things properly}\r
   state.resultstr := '';\r
 begin\r
   {destroy things properly}\r
   state.resultstr := '';\r


@@ -397,7 +452,7 @@ begin
   state.parsepacket := false;\r
 end;\r
 \r
   state.parsepacket := false;\r
 end;\r
 \r

-procedure setstate_forward(const name:string;var state:tdnsstate;family:integer);\r
+procedure setstate_forward(const name:ansistring;var state:tdnsstate;family:integer);\r

 begin\r
   setstate_request_init(name,state);\r
   state.forwardfamily := family;\r
 begin\r
   setstate_request_init(name,state);\r
   state.forwardfamily := family;\r


@@ -413,6 +468,13 @@ begin
   state.requesttype := querytype_ptr;\r
 end;\r
 \r
   state.requesttype := querytype_ptr;\r
 end;\r
 \r

+procedure setstate_custom(const name:ansistring; requesttype:integer; var state:tdnsstate);\r
+begin\r
+  setstate_request_init(name,state);\r
+  state.requesttype := requesttype;\r
+end;\r
+\r
+\r

 procedure setstate_failure(var state:tdnsstate);\r
 begin\r
   state.resultstr := '';\r
 procedure setstate_failure(var state:tdnsstate);\r
 begin\r
   state.resultstr := '';\r


@@ -516,23 +578,7 @@ begin
 \r
     {no cnames found, no items of correct type found}\r
     if state.forwardfamily <> 0 then goto failure;\r
 \r
     {no cnames found, no items of correct type found}\r
     if state.forwardfamily <> 0 then goto failure;\r

-{$ifdef ipv6}\r
-    if (state.requesttype = querytype_a) then begin\r
-      {v6 only: in case of forward, look for AAAA in alternative section}\r
-      for a := state.numrr1[0]+state.numrr1[1]+state.numrr1[2] to (state.numrr2-1) do begin\r
-        rrptemp := @state.rrdata[1+a*sizeof(trrpointer)];\r
-        rrtemp := rrptemp.p;\r
-        b := rrptemp.len;\r
-        if rrtemp.requesttype = querytype_aaaa then begin\r
-          setstate_return(rrptemp^,b,state);\r
-          exit;\r
-        end;\r
-      end;\r
-      {no AAAA's found in alternative, do a recursive lookup for them}\r
-      state.requesttype := querytype_aaaa;\r
-      goto recursed;\r
-    end;\r
-{$endif}\r
+\r

     goto failure;\r
 recursed:\r
     {here it needs recursed lookup}\r
     goto failure;\r
 recursed:\r
     {here it needs recursed lookup}\r


@@ -580,18 +626,18 @@ end;
   type\r
     tip_addr_string=packed record\r
       Next :pointer;\r
   type\r
     tip_addr_string=packed record\r
       Next :pointer;\r

-      IpAddress : array[0..15] of char;\r
-      ipmask    : array[0..15] of char;\r
+      IpAddress : array[0..15] of ansichar;\r
+      ipmask    : array[0..15] of ansichar;\r

       context   : dword;\r
     end;\r
     pip_addr_string=^tip_addr_string;\r
     tFIXED_INFO=packed record\r
       context   : dword;\r
     end;\r
     pip_addr_string=^tip_addr_string;\r
     tFIXED_INFO=packed record\r

-       HostName         : array[0..MAX_HOSTNAME_LEN-1] of char;\r
-       DomainName       : array[0..MAX_DOMAIN_NAME_LEN-1] of char;\r
+       HostName         : array[0..MAX_HOSTNAME_LEN-1] of ansichar;\r
+       DomainName       : array[0..MAX_DOMAIN_NAME_LEN-1] of ansichar;\r

        currentdnsserver : pip_addr_string;\r
        dnsserverlist    : tip_addr_string;\r
        nodetype         : longint;\r
        currentdnsserver : pip_addr_string;\r
        dnsserverlist    : tip_addr_string;\r
        nodetype         : longint;\r

-       ScopeId          : array[0..MAX_SCOPE_ID_LEN + 4] of char;\r
+       ScopeId          : array[0..MAX_SCOPE_ID_LEN + 4] of ansichar;\r

        enablerouting    : longbool;\r
        enableproxy      : longbool;\r
        enabledns        : longbool;\r
        enablerouting    : longbool;\r
        enableproxy      : longbool;\r
        enabledns        : longbool;\r


@@ -610,7 +656,7 @@ var
     currentdnsserver : pip_addr_string;\r
   {$else}\r
     t:textfile;\r
     currentdnsserver : pip_addr_string;\r
   {$else}\r
     t:textfile;\r

-    s:string;\r
+    s:ansistring;\r

     a:integer;\r
   {$endif}\r
 begin\r
     a:integer;\r
   {$endif}\r
 begin\r


@@ -671,7 +717,7 @@ begin
   end;\r
 end;\r
 \r
   end;\r
 end;\r
 \r

-function getcurrentsystemnameserver(var id:integer):string;\r
+function getcurrentsystemnameserver(var id:integer):ansistring;\r

 var\r
   counter : integer;\r
 \r
 var\r
   counter : integer;\r
 \r


@@ -703,6 +749,100 @@ begin
 \r
 end;\r
 \r
 \r
 end;\r
 \r

+\r
+\r
+{$ifdef ipv6}\r
+\r
+{$ifdef linux}\r
+function getv6localips:tbiniplist;\r
+var\r
+  t:textfile;\r
+  s,s2:ansistring;\r
+  ip:tbinip;\r
+  a:integer;\r
+begin\r
+  result := biniplist_new;\r
+\r
+  assignfile(t,'/proc/net/if_inet6');\r
+  {$i-}reset(t);{$i+}\r
+  if ioresult <> 0 then exit; {none found, return empty list}\r
+\r
+  while not eof(t) do begin\r
+    readln(t,s);\r
+    s2 := '';\r
+    for a := 0 to 7 do begin\r
+      if (s2 <> '') then s2 := s2 + ':';\r
+      s2 := s2 + copy(s,(a shl 2)+1,4);\r
+    end;\r
+    ipstrtobin(s2,ip);\r
+    if ip.family <> 0 then biniplist_add(result,ip);\r
+  end;\r
+  closefile(t);\r
+end;\r
+\r
+{$else}\r
+\r
+{the following code's purpose is to determine what IP windows would come from, to reach an IP\r
+it can be abused to find if there's any global v6 IPs, getaddrinfo seems unreliable (not working on XP atleast)\r
+}\r
+const\r
+  SIO_ROUTING_INTERFACE_QUERY = $c8000014;\r
+  function WSAIoctl(s: TSocket; code:integer; const Buf; len: Integer; var output; outlen:integer; var outreturned: Integer; overlapped:pointer; completion: pointer): Integer; stdcall; external 'ws2_32.dll' name 'WSAIoctl';\r
+\r
+function getlocalipforip(const ip:tbinip):tbinip;\r
+var\r
+  handle:integer;\r
+  a,b:integer;\r
+  inaddrv,inaddrv2:tinetsockaddrv;\r
+  srcx:winsock.tsockaddr absolute inaddrv2;\r
+begin\r
+  makeinaddrv(ip,'0',inaddrv);\r
+  handle := Socket(inaddrv.inaddr.family,SOCK_DGRAM,IPPROTO_UDP);\r
+  if WSAIoctl(handle, SIO_ROUTING_INTERFACE_QUERY, inaddrv, sizeof(inaddrv), inaddrv2, sizeof(inaddrv2), a, nil, nil) <> 0\r
+  then raise exception.create('getlocalipforip failed with error: '+inttostr(wsagetlasterror));\r
+  result := inaddrvtobinip(inaddrv2);\r
+  closesocket(handle);\r
+end;\r
+\r
+function getv6localips:tbiniplist;\r
+begin\r
+  result := biniplist_new;\r
+  {this IP is chosen because it's the first normal global v6 IP that has no special purpose}\r
+  biniplist_add(result,getlocalipforip(ipstrtobinf('2001:200::')));\r
+end;\r
+{$endif}\r
+\r
+procedure initpreferredmode;\r
+var\r
+  l:tbiniplist;\r
+  a:integer;\r
+  ip:tbinip;\r
+  ipmask_global,ipmask_6to4,ipmask_teredo:tbinip;\r
+\r
+begin\r
+  if preferredmodeinited then exit;\r
+  if useaf <> useaf_default then exit;\r
+  l := getv6localips;\r
+  if biniplist_getcount(l) = 0 then exit;\r
+  useaf := useaf_preferv4;\r
+  ipstrtobin('2000::',ipmask_global);\r
+  ipstrtobin('2001::',ipmask_teredo);\r
+  ipstrtobin('2002::',ipmask_6to4);\r
+  {if there is any v6 IP which is globally routable and not 6to4 and not teredo, prefer v6}\r
+  for a := biniplist_getcount(l)-1 downto 0 do begin\r
+    ip := biniplist_get(l,a);\r
+    if not comparebinipmask(ip,ipmask_global,3) then continue;\r
+    if comparebinipmask(ip,ipmask_teredo,32) then continue;\r
+    if comparebinipmask(ip,ipmask_6to4,16) then continue;\r
+    useaf := useaf_preferv6;\r
+    preferredmodeinited := true;\r
+    exit;\r
+  end;\r
+end;\r
+\r
+{$endif}\r
+\r
+\r

 {  quick and dirty description of dns packet structure to aid writing and\r
    understanding of parser code, refer to appropriate RFCs for proper specs\r
 - all words are network order\r
 {  quick and dirty description of dns packet structure to aid writing and\r
    understanding of parser code, refer to appropriate RFCs for proper specs\r
 - all words are network order\r