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HttpUtils.pm: better parsing of DNS answers (Forum #53309)
git-svn-id: https://svn.fhem.de/fhem/trunk@11459 2b470e98-0d58-463d-a4d8-8e2adae1ed80
This commit is contained in:
rudolfkoenig
parent
3509e3e6f3
commit
f7327d99c1
@ -102,8 +102,25 @@ HttpUtils_File($)
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return (1, undef, $data);
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}
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sub ip2str($) { return sprintf("%d.%d.%d.%d", unpack("C*", shift)); }
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my %HU_dnsCache;
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sub
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HttpUtils_dnsParse($$)
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{
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my ($a, $ql) = @_;
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return "wrong message ID" if(unpack("H*",substr($a,0,2)) ne "7072");
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while(length($a) >= $ql+16) {
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return (undef, substr($a,$ql+12,4), unpack("N",substr($a,$ql+6,4)))
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if(unpack("N",substr($a,$ql+2,4)) == 0x10001);
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$ql += 12+unpack("n",substr($a,$ql+10));
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}
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return "No A record found";
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}
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# { HttpUtils_gethostbyname({timeout=>4}, "google.com", sub(){my($h,$e,$a)=@_;;
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# fhem("trigger global ".($e ? "ERR:$e": ("IP:".ip2str($a)))) }) }
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sub
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HttpUtils_gethostbyname($$$)
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{
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my ($hash, $host, $fn) = @_;
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@ -116,60 +133,64 @@ HttpUtils_gethostbyname($$$)
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my $dnsServer = AttrVal("global", "dnsServer", undef);
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if(!$dnsServer) {
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my @addr = gethostbyname($host); # blocking version
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my $err = ($addr[0] ? undef : "gethostbyname $host failed");
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$fn->($hash, $err, $addr[4]);
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my $iaddr = inet_aton($host);
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my $err;
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if(!defined($iaddr)) {
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my @addr = gethostbyname($host); # This is still blocking
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$err = ($addr[0] ? undef : "gethostbyname $host failed");
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$iaddr = $addr[4];
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}
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$fn->($hash, $err, $iaddr);
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return;
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}
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my $now = gettimeofday(); # check the cache
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return $fn->($hash, undef, $HU_dnsCache{$host}{addr})
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return $fn->($hash, undef, $HU_dnsCache{$host}{addr}) # check the cache
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if($HU_dnsCache{$host} &&
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$HU_dnsCache{$host}{TS}+$HU_dnsCache{$host}{TTL} > $now);
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$HU_dnsCache{$host}{TS}+$HU_dnsCache{$host}{TTL} > gettimeofday());
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# Direct DNS Query via UDP
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my $c = IO::Socket::INET->new(Proto=>'udp', PeerAddr=>"$dnsServer:53");
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return $fn->($hash, "Cant create UDP socket:$!", undef) if(!$c);
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my %dh = ( conn=>$c, FD=>$c->fileno(), NAME=>"DNS",
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addr=>$dnsServer, callback=>$hash->{callback} );
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my %timerHash = ( hash => \%dh );
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my %dh = ( conn=>$c, FD=>$c->fileno(), NAME=>"DNS",
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addr=>$dnsServer, callback=>$fn );
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my %timerHash = ( hash => \%dh );
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my $bhost = join("", map { pack("CA*",length($_),$_) } split(/\./, $host));
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my $qry = pack("nnnnnn", 0x7072,0x0100,1,0,0,0) . $bhost . pack("Cnn", 0,1,1);
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my $ql = length($qry);
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my $ret = syswrite $dh{conn}, $qry;
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if(!$ret || $ret != $ql) {
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my $err = $!;
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HttpUtils_Close(\%dh);
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return $fn->($hash, "DNS write error: $err", undef);
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}
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my $dnsTo = 0.25;
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$dh{directReadFn} = sub() { # Parse the answer
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RemoveInternalTimer(\%timerHash);
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my $buf;
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my $len = sysread($dh{conn},$buf,65536);
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HttpUtils_Close(\%dh);
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# Log 1, "DNS ANSWER $len:".unpack("H*", $buf);
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return $fn->($hash, "DNS: Cannot resolve $host", undef)
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if(unpack("n",substr($buf,6,2)) == 0);
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return $fn->($hash, "DNS: Short answer for $host", undef)
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if($len < $ql+16);
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return $fn->($hash, "DNS: Wrong answer for $host", undef)
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if(unpack("H*",substr($buf,$ql+2,4)) ne "00010001" || # Type A + IP
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unpack("n",substr($buf,$ql+10,2)) != 4);
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my $ttl = unpack("N",substr($buf,$ql+6,4));
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my $addr = substr($buf,$ql+12,4);
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Log 4, "DNS result for $host: ".unpack("H*",$addr).", ttl:$ttl";
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$HU_dnsCache{$host}{TS} = $now;
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Log 5, "DNS ANSWER $len:".unpack("H*", $buf);
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my ($err, $addr, $ttl) = HttpUtils_dnsParse($buf,$ql);
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return $fn->($hash, "DNS: $err", undef) if($err);
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Log 4, "DNS result for $host: ".ip2str($addr).", ttl:$ttl";
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$HU_dnsCache{$host}{TS} = gettimeofday();
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$HU_dnsCache{$host}{TTL} = $ttl;
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$HU_dnsCache{$host}{addr} = $addr;
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return $fn->($hash, undef, $addr);
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};
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$selectlist{\%dh} = \%dh;
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InternalTimer(gettimeofday()+($hash->{timeout}/2),
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"HttpUtils_ReadErr",\%timerHash,0);
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my $dnsQuery;
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$dnsQuery = sub()
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{
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$dnsTo *= 2;
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return HttpUtils_Err(\%timerHash, "DNS") if($dnsTo > $hash->{timeout}/2);
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my $ret = syswrite $dh{conn}, $qry;
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if(!$ret || $ret != $ql) {
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my $err = $!;
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HttpUtils_Close(\%dh);
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return $fn->($hash, "DNS write error: $err", undef);
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}
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InternalTimer(gettimeofday()+$dnsTo, $dnsQuery, \%timerHash, 0);
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};
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$dnsQuery->();
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}
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@ -600,11 +621,8 @@ HttpUtils_ParseAnswer($$)
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# noshutdown(1),shutdown(0),httpversion("1.0"),ignoreredirects(0)
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# method($data ? "POST" : "GET"),keepalive(0),sslargs({})
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# Example:
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# HttpUtils_NonblockingGet({
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# url=>"http://192.168.178.112:8888/fhem",
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# myParam=>7,
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# callback=>sub($$$){ Log 1,"$_[0]->{myParam} ERR:$_[1] DATA:$_[2]" }
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# })
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# HttpUtils_NonblockingGet({ url=>"http://www.google.de/", myParam=>7,
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# callback=>sub($$$){ Log 1,"$_[0]->{myParam} ERR:$_[1] DATA:$_[2]" } })
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sub
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HttpUtils_NonblockingGet($)
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{
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