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e14f094b BH |
1 | /* |
2 | PowerDNS Versatile Database Driven Nameserver | |
a5c1b943 | 3 | Copyright (C) 2002 - 2015 PowerDNS.COM BV |
e14f094b BH |
4 | |
5 | This program is free software; you can redistribute it and/or modify | |
d0166f4a BH |
6 | it under the terms of the GNU General Public License version 2 as |
7 | published by the Free Software Foundation | |
e14f094b | 8 | |
f782fe38 MH |
9 | Additionally, the license of this program contains a special |
10 | exception which allows to distribute the program in binary form when | |
11 | it is linked against OpenSSL. | |
12 | ||
e14f094b BH |
13 | This program is distributed in the hope that it will be useful, |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
06bd9ccf | 20 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
e14f094b | 21 | */ |
705f31ae BH |
22 | |
23 | ||
870a0fe4 AT |
24 | #ifdef HAVE_CONFIG_H |
25 | #include "config.h" | |
26 | #endif | |
36c5ee42 | 27 | #include "utility.hh" |
e14f094b | 28 | #include "lwres.hh" |
e14f094b | 29 | #include <iostream> |
81883dcc | 30 | #include "dnsrecords.hh" |
e14f094b BH |
31 | #include <errno.h> |
32 | #include "misc.hh" | |
33 | #include <algorithm> | |
34 | #include <sstream> | |
35 | #include <cstring> | |
36 | #include <string> | |
37 | #include <vector> | |
e14f094b BH |
38 | #include "dns.hh" |
39 | #include "qtype.hh" | |
5c409fa2 | 40 | #include "pdnsexception.hh" |
e14f094b | 41 | #include "arguments.hh" |
5c633640 BH |
42 | #include "sstuff.hh" |
43 | #include "syncres.hh" | |
ea634573 BH |
44 | #include "dnswriter.hh" |
45 | #include "dnsparser.hh" | |
aab4adb0 | 46 | #include "logger.hh" |
51e2144e | 47 | #include "dns_random.hh" |
263f6a5a | 48 | #include <boost/scoped_array.hpp> |
51e2144e | 49 | #include <boost/algorithm/string.hpp> |
12ce523e | 50 | #include "validate-recursor.hh" |
c4443ccb | 51 | #include "ednssubnet.hh" |
51e2144e | 52 | |
81883dcc BH |
53 | //! returns -2 for OS limits error, -1 for permanent error that has to do with remote **transport**, 0 for timeout, 1 for success |
54 | /** lwr is only filled out in case 1 was returned, and even when returning 1 for 'success', lwr might contain DNS errors | |
55 | Never throws! | |
56 | */ | |
376effcf | 57 | int asyncresolve(const ComboAddress& ip, const DNSName& domain, int type, bool doTCP, bool sendRDQuery, int EDNS0Level, struct timeval* now, boost::optional<Netmask>& srcmask, LWResult *lwr) |
e14f094b | 58 | { |
a683e8bd RG |
59 | size_t len; |
60 | size_t bufsize=g_outgoingEDNSBufsize; | |
263f6a5a | 61 | scoped_array<unsigned char> buf(new unsigned char[bufsize]); |
ea634573 | 62 | vector<uint8_t> vpacket; |
51e2144e | 63 | // string mapped0x20=dns0x20(domain); |
ea634573 BH |
64 | DNSPacketWriter pw(vpacket, domain, type); |
65 | ||
c1d73d94 | 66 | pw.getHeader()->rd=sendRDQuery; |
51e2144e | 67 | pw.getHeader()->id=dns_random(0xffff); |
5a7d2a18 PL |
68 | /* RFC 6840 section 5.9: |
69 | * This document further specifies that validating resolvers SHOULD set | |
70 | * the CD bit on every upstream query. This is regardless of whether | |
71 | * the CD bit was set on the incoming query [...] | |
72 | * | |
73 | * sendRDQuery is only true if the qname is part of a forward-zone-recurse (or | |
74 | * set in the forward-zone-file), so we use this as an indicator for it being | |
75 | * an "upstream query". To stay true to "dnssec=off means 3.X behaviour", we | |
76 | * only set +CD on forwarded query in any mode other than dnssec=off. | |
77 | */ | |
e7b18884 | 78 | pw.getHeader()->cd=(sendRDQuery && g_dnssecmode != DNSSECMode::Off); |
5a7d2a18 | 79 | |
81883dcc | 80 | string ping; |
7bb598a0 | 81 | bool weWantEDNSSubnet=false; |
a2e0174c | 82 | if(EDNS0Level) { |
81883dcc | 83 | DNSPacketWriter::optvect_t opts; |
376effcf | 84 | if(srcmask) { |
85 | EDNSSubnetOpts eo; | |
86 | eo.source = *srcmask; | |
bf4ab707 | 87 | // cout<<"Adding request mask: "<<eo.source.toString()<<endl; |
376effcf | 88 | opts.push_back(make_pair(8, makeEDNSSubnetOptsString(eo))); |
89 | srcmask=boost::optional<Netmask>(); // this is also our return value | |
7bb598a0 | 90 | weWantEDNSSubnet=true; |
376effcf | 91 | } |
93d4a890 | 92 | |
12ce523e | 93 | pw.addOpt(g_outgoingEDNSBufsize, 0, g_dnssecmode == DNSSECMode::Off ? 0 : EDNSOpts::DNSSECOK, opts); |
2188dcc3 BH |
94 | pw.commit(); |
95 | } | |
81883dcc | 96 | lwr->d_rcode = 0; |
81883dcc | 97 | lwr->d_haveEDNS = false; |
eefd15f9 BH |
98 | int ret; |
99 | ||
100 | DTime dt; | |
4c4765c1 | 101 | dt.set(); |
102 | *now=dt.getTimeval(); | |
263f6a5a | 103 | errno=0; |
5c633640 | 104 | if(!doTCP) { |
4ef015cd | 105 | int queryfd; |
996c89cc BH |
106 | if(ip.sin4.sin_family==AF_INET6) |
107 | g_stats.ipv6queries++; | |
108 | ||
a683e8bd | 109 | if((ret=asendto((const char*)&*vpacket.begin(), vpacket.size(), 0, ip, pw.getHeader()->id, |
232f0877 | 110 | domain, type, &queryfd)) < 0) { |
998a4334 | 111 | return ret; // passes back the -2 EMFILE |
5c633640 BH |
112 | } |
113 | ||
114 | // sleep until we see an answer to this, interface to mtasker | |
115 | ||
263f6a5a | 116 | ret=arecvfrom(reinterpret_cast<char *>(buf.get()), bufsize-1,0, ip, &len, pw.getHeader()->id, |
232f0877 | 117 | domain, type, queryfd, now); |
e14f094b | 118 | } |
5c633640 | 119 | else { |
998a4334 | 120 | try { |
93f4e5ce | 121 | Socket s(ip.sin4.sin_family, SOCK_STREAM); |
fdf05fd4 | 122 | |
998a4334 | 123 | s.setNonBlocking(); |
1652a63e | 124 | ComboAddress local = getQueryLocalAddress(ip.sin4.sin_family, 0); |
3ac2a2ab | 125 | |
5a38281c | 126 | s.bind(local); |
4957a608 | 127 | |
fdf05fd4 BH |
128 | ComboAddress remote = ip; |
129 | remote.sin4.sin_port = htons(53); | |
130 | s.connect(remote); | |
998a4334 | 131 | |
263f6a5a BH |
132 | uint16_t tlen=htons(vpacket.size()); |
133 | char *lenP=(char*)&tlen; | |
998a4334 BH |
134 | const char *msgP=(const char*)&*vpacket.begin(); |
135 | string packet=string(lenP, lenP+2)+string(msgP, msgP+vpacket.size()); | |
136 | ||
137 | ret=asendtcp(packet, &s); | |
138 | if(!(ret>0)) | |
4957a608 | 139 | return ret; |
998a4334 BH |
140 | |
141 | packet.clear(); | |
825fa717 | 142 | ret=arecvtcp(packet, 2, &s, false); |
998a4334 | 143 | if(!(ret > 0)) |
4957a608 | 144 | return ret; |
998a4334 | 145 | |
a683e8bd | 146 | memcpy(&tlen, packet.c_str(), sizeof(tlen)); |
263f6a5a | 147 | len=ntohs(tlen); // switch to the 'len' shared with the rest of the function |
998a4334 | 148 | |
825fa717 | 149 | ret=arecvtcp(packet, len, &s, false); |
998a4334 | 150 | if(!(ret > 0)) |
4957a608 | 151 | return ret; |
998a4334 | 152 | |
263f6a5a | 153 | if(len > bufsize) { |
4957a608 BH |
154 | bufsize=len; |
155 | scoped_array<unsigned char> narray(new unsigned char[bufsize]); | |
156 | buf.swap(narray); | |
998a4334 | 157 | } |
263f6a5a BH |
158 | memcpy(buf.get(), packet.c_str(), len); |
159 | ||
998a4334 BH |
160 | ret=1; |
161 | } | |
162 | catch(NetworkError& ne) { | |
163 | ret = -2; // OS limits error | |
66ab6a63 | 164 | } |
5c633640 | 165 | } |
998a4334 | 166 | |
81883dcc | 167 | |
26de3092 BH |
168 | lwr->d_usec=dt.udiff(); |
169 | *now=dt.getTimeval(); | |
170 | ||
263f6a5a BH |
171 | if(ret <= 0) // includes 'timeout' |
172 | return ret; | |
e14f094b | 173 | |
e325f20c | 174 | lwr->d_records.clear(); |
c836dc19 | 175 | try { |
f1f85f12 | 176 | lwr->d_tcbit=0; |
263f6a5a BH |
177 | MOADNSParser mdp((const char*)buf.get(), len); |
178 | lwr->d_aabit=mdp.d_header.aa; | |
179 | lwr->d_tcbit=mdp.d_header.tc; | |
180 | lwr->d_rcode=mdp.d_header.rcode; | |
181 | ||
81883dcc BH |
182 | if(mdp.d_header.rcode == RCode::FormErr && mdp.d_qname.empty() && mdp.d_qtype == 0 && mdp.d_qclass == 0) { |
183 | return 1; // this is "success", the error is set in lwr->d_rcode | |
184 | } | |
185 | ||
e325f20c | 186 | if(domain != mdp.d_qname) { |
c5c066bf | 187 | if(!mdp.d_qname.empty() && domain.toString().find((char)0) == string::npos /* ugly */) {// embedded nulls are too noisy, plus empty domains are too |
4957a608 | 188 | L<<Logger::Notice<<"Packet purporting to come from remote server "<<ip.toString()<<" contained wrong answer: '" << domain << "' != '" << mdp.d_qname << "'" << endl; |
01608dca | 189 | } |
284aa5c2 | 190 | // unexpected count has already been done @ pdns_recursor.cc |
2353fffa BH |
191 | goto out; |
192 | } | |
e325f20c | 193 | |
194 | for(const auto& a : mdp.d_answers) | |
195 | lwr->d_records.push_back(a.first); | |
81883dcc BH |
196 | |
197 | EDNSOpts edo; | |
57769f13 | 198 | if(EDNS0Level > 0 && getEDNSOpts(mdp, &edo)) { |
81883dcc | 199 | lwr->d_haveEDNS = true; |
376effcf | 200 | |
7bb598a0 | 201 | if(weWantEDNSSubnet) { |
202 | for(const auto& opt : edo.d_options) { | |
203 | if(opt.first==8) { | |
204 | EDNSSubnetOpts reso; | |
205 | if(getEDNSSubnetOptsFromString(opt.second, &reso)) { | |
206 | // cerr<<"EDNS Subnet response: "<<reso.source.toString()<<", scope: "<<reso.scope.toString()<<", family = "<<reso.scope.getNetwork().sin4.sin_family<<endl; | |
207 | if(reso.scope.getBits()) | |
208 | srcmask = reso.scope; | |
209 | } | |
210 | } | |
211 | } | |
376effcf | 212 | } |
81883dcc BH |
213 | } |
214 | ||
263f6a5a | 215 | return 1; |
c836dc19 | 216 | } |
fdbf35ac | 217 | catch(std::exception &mde) { |
aab4adb0 | 218 | if(::arg().mustDo("log-common-errors")) |
263f6a5a | 219 | L<<Logger::Notice<<"Unable to parse packet from remote server "<<ip.toString()<<": "<<mde.what()<<endl; |
81883dcc BH |
220 | lwr->d_rcode = RCode::FormErr; |
221 | g_stats.serverParseError++; | |
222 | return 1; // success - oddly enough | |
aab4adb0 | 223 | } |
c836dc19 | 224 | catch(...) { |
ad1bb608 | 225 | L<<Logger::Notice<<"Unknown error parsing packet from remote server"<<endl; |
c836dc19 | 226 | } |
263f6a5a | 227 | |
aab4adb0 | 228 | g_stats.serverParseError++; |
263f6a5a | 229 | |
2353fffa | 230 | out: |
81883dcc BH |
231 | if(!lwr->d_rcode) |
232 | lwr->d_rcode=RCode::ServFail; | |
263f6a5a BH |
233 | |
234 | return -1; | |
e14f094b BH |
235 | } |
236 |