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Commit | Line | Data |
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12c86877 | 1 | /* |
12471842 PL |
2 | * This file is part of PowerDNS or dnsdist. |
3 | * Copyright -- PowerDNS.COM B.V. and its contributors | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of version 2 of the GNU General Public License as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * In addition, for the avoidance of any doubt, permission is granted to | |
10 | * link this program with OpenSSL and to (re)distribute the binaries | |
11 | * produced as the result of such linking. | |
12 | * | |
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 | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
21 | */ | |
870a0fe4 AT |
22 | #ifdef HAVE_CONFIG_H |
23 | #include "config.h" | |
24 | #endif | |
379ab445 | 25 | #include "packetcache.hh" |
b636533b | 26 | #include "utility.hh" |
12c86877 | 27 | #include "dnsproxy.hh" |
5c409fa2 | 28 | #include "pdnsexception.hh" |
12c86877 BH |
29 | #include <sys/types.h> |
30 | #include <errno.h> | |
31 | #include "dns.hh" | |
32 | #include "logger.hh" | |
33 | #include "statbag.hh" | |
d2116c15 | 34 | #include "dns_random.hh" |
c4e084f2 | 35 | #include "stubresolver.hh" |
c4e084f2 | 36 | #include "arguments.hh" |
12c86877 BH |
37 | |
38 | extern StatBag S; | |
12c86877 BH |
39 | |
40 | DNSProxy::DNSProxy(const string &remote) | |
41 | { | |
12c86877 BH |
42 | pthread_mutex_init(&d_lock,0); |
43 | d_resanswers=S.getPointer("recursing-answers"); | |
44 | d_resquestions=S.getPointer("recursing-questions"); | |
45 | d_udpanswers=S.getPointer("udp-answers"); | |
2b78726c PL |
46 | |
47 | vector<string> addresses; | |
48 | stringtok(addresses, remote, " ,\t"); | |
40c9a111 RG |
49 | d_remote = ComboAddress(addresses[0], 53); |
50 | ||
51 | if((d_sock=socket(d_remote.sin4.sin_family, SOCK_DGRAM,0))<0) { | |
3f81d239 | 52 | throw PDNSException(string("socket: ")+strerror(errno)); |
40c9a111 RG |
53 | } |
54 | ||
c0cc6559 | 55 | ComboAddress local; |
40c9a111 | 56 | if(d_remote.sin4.sin_family==AF_INET) { |
c0cc6559 | 57 | local = ComboAddress("0.0.0.0"); |
40c9a111 RG |
58 | } |
59 | else { | |
c0cc6559 | 60 | local = ComboAddress("::"); |
40c9a111 | 61 | } |
c0cc6559 | 62 | |
40c9a111 | 63 | unsigned int n=0; |
12c86877 | 64 | for(;n<10;n++) { |
d2116c15 | 65 | local.sin4.sin_port = htons(10000+dns_random(50000)); |
12c86877 | 66 | |
c0cc6559 | 67 | if(::bind(d_sock, (struct sockaddr *)&local, local.getSocklen()) >= 0) |
12c86877 BH |
68 | break; |
69 | } | |
70 | if(n==10) { | |
3897b9e1 | 71 | closesocket(d_sock); |
12c86877 | 72 | d_sock=-1; |
3f81d239 | 73 | throw PDNSException(string("binding dnsproxy socket: ")+strerror(errno)); |
12c86877 BH |
74 | } |
75 | ||
40c9a111 RG |
76 | if(connect(d_sock, (sockaddr *)&d_remote, d_remote.getSocklen())<0) { |
77 | throw PDNSException("Unable to UDP connect to remote nameserver "+d_remote.toStringWithPort()+": "+stringerror()); | |
78 | } | |
12c86877 | 79 | |
d2116c15 | 80 | d_xor=dns_random(0xffff); |
e6a9dde5 | 81 | g_log<<Logger::Error<<"DNS Proxy launched, local port "<<ntohs(local.sin4.sin_port)<<", remote "<<d_remote.toStringWithPort()<<endl; |
12c86877 BH |
82 | } |
83 | ||
84 | void DNSProxy::go() | |
85 | { | |
86 | pthread_t tid; | |
87 | pthread_create(&tid,0,&launchhelper,this); | |
88 | } | |
89 | ||
d59b894d | 90 | //! look up qname aname with r->qtype, plonk it in the answer section of 'r' with name target |
561434a6 | 91 | bool DNSProxy::completePacket(DNSPacket *r, const DNSName& target,const DNSName& aname) |
d59b894d | 92 | { |
c4e084f2 | 93 | if(r->d_tcp) { |
c4e084f2 PD |
94 | vector<DNSZoneRecord> ips; |
95 | int ret1 = 0, ret2 = 0; | |
96 | ||
97 | if(r->qtype == QType::A || r->qtype == QType::ANY) | |
98 | ret1 = stubDoResolve(target, QType::A, ips); | |
99 | if(r->qtype == QType::AAAA || r->qtype == QType::ANY) | |
100 | ret2 = stubDoResolve(target, QType::AAAA, ips); | |
101 | ||
102 | if(ret1 != RCode::NoError || ret2 != RCode::NoError) { | |
e6a9dde5 | 103 | g_log<<Logger::Error<<"Error resolving for ALIAS "<<target<<", returning SERVFAIL"<<endl; |
c4e084f2 PD |
104 | } |
105 | ||
106 | for (auto &ip : ips) | |
107 | { | |
108 | ip.dr.d_name = target; | |
109 | r->addRecord(ip); | |
110 | } | |
111 | ||
112 | uint16_t len=htons(r->getString().length()); | |
113 | string buffer((const char*)&len, 2); | |
114 | buffer.append(r->getString()); | |
115 | writen2WithTimeout(r->getSocket(), buffer.c_str(), buffer.length(), ::arg().asNum("tcp-idle-timeout")); | |
116 | ||
117 | return true; | |
118 | } | |
119 | ||
d59b894d | 120 | uint16_t id; |
121 | { | |
122 | Lock l(&d_lock); | |
123 | id=getID_locked(); | |
124 | ||
125 | ConntrackEntry ce; | |
126 | ce.id = r->d.id; | |
127 | ce.remote = r->d_remote; | |
128 | ce.outsock = r->getSocket(); | |
129 | ce.created = time( NULL ); | |
130 | ce.qtype = r->qtype.getCode(); | |
561434a6 | 131 | ce.qname = target; |
d59b894d | 132 | ce.anyLocal = r->d_anyLocal; |
133 | ce.complete = r; | |
134 | ce.aname=aname; | |
135 | d_conntrack[id]=ce; | |
136 | } | |
137 | ||
138 | vector<uint8_t> packet; | |
139 | DNSPacketWriter pw(packet, target, r->qtype.getCode()); | |
140 | pw.getHeader()->rd=true; | |
141 | pw.getHeader()->id=id ^ d_xor; | |
142 | ||
143 | if(send(d_sock,&packet[0], packet.size() , 0)<0) { // zoom | |
e6a9dde5 | 144 | g_log<<Logger::Error<<"Unable to send a packet to our recursing backend: "<<stringerror()<<endl; |
d59b894d | 145 | } |
146 | ||
147 | return true; | |
148 | ||
149 | } | |
150 | ||
151 | ||
12c86877 BH |
152 | /** This finds us an unused or stale ID. Does not actually clean the contents */ |
153 | int DNSProxy::getID_locked() | |
154 | { | |
155 | map_t::iterator i; | |
156 | for(int n=0;;++n) { | |
157 | i=d_conntrack.find(n); | |
158 | if(i==d_conntrack.end()) { | |
159 | return n; | |
160 | } | |
161 | else if(i->second.created<time(0)-60) { | |
d59b894d | 162 | if(i->second.created) { |
e6a9dde5 | 163 | g_log<<Logger::Warning<<"Recursive query for remote "<< |
85db02c5 | 164 | i->second.remote.toStringWithPort()<<" with internal id "<<n<< |
4957a608 | 165 | " was not answered by backend within timeout, reusing id"<<endl; |
d59b894d | 166 | delete i->second.complete; |
bb6e54fe | 167 | S.inc("recursion-unanswered"); |
d59b894d | 168 | } |
12c86877 BH |
169 | return n; |
170 | } | |
171 | } | |
172 | } | |
173 | ||
174 | void DNSProxy::mainloop(void) | |
175 | { | |
176 | try { | |
177 | char buffer[1500]; | |
a683e8bd | 178 | ssize_t len; |
12c86877 | 179 | |
65d8e171 KN |
180 | struct msghdr msgh; |
181 | struct iovec iov; | |
182 | char cbuf[256]; | |
40c9a111 | 183 | ComboAddress fromaddr; |
65d8e171 | 184 | |
12c86877 | 185 | for(;;) { |
40c9a111 RG |
186 | socklen_t fromaddrSize = sizeof(fromaddr); |
187 | len=recvfrom(d_sock, buffer, sizeof(buffer),0, (struct sockaddr*) &fromaddr, &fromaddrSize); // answer from our backend | |
a683e8bd | 188 | if(len<(ssize_t)sizeof(dnsheader)) { |
4957a608 | 189 | if(len<0) |
e6a9dde5 | 190 | g_log<<Logger::Error<<"Error receiving packet from recursor backend: "<<stringerror()<<endl; |
4957a608 | 191 | else if(len==0) |
e6a9dde5 | 192 | g_log<<Logger::Error<<"Error receiving packet from recursor backend, EOF"<<endl; |
4957a608 | 193 | else |
e6a9dde5 | 194 | g_log<<Logger::Error<<"Short packet from recursor backend, "<<len<<" bytes"<<endl; |
4957a608 BH |
195 | |
196 | continue; | |
12c86877 | 197 | } |
40c9a111 | 198 | if (fromaddr != d_remote) { |
e6a9dde5 | 199 | g_log<<Logger::Error<<"Got answer from unexpected host "<<fromaddr.toStringWithPort()<<" instead of our recursor backend "<<d_remote.toStringWithPort()<<endl; |
40c9a111 RG |
200 | continue; |
201 | } | |
12c86877 BH |
202 | (*d_resanswers)++; |
203 | (*d_udpanswers)++; | |
88c1bc50 | 204 | dnsheader d; |
caa6eefa | 205 | memcpy(&d,buffer,sizeof(d)); |
12c86877 | 206 | { |
4957a608 | 207 | Lock l(&d_lock); |
bf549564 | 208 | #if BYTE_ORDER == BIG_ENDIAN |
4957a608 BH |
209 | // this is needed because spoof ID down below does not respect the native byteorder |
210 | d.id = ( 256 * (uint16_t)buffer[1] ) + (uint16_t)buffer[0]; | |
a899e13a | 211 | #endif |
4957a608 BH |
212 | map_t::iterator i=d_conntrack.find(d.id^d_xor); |
213 | if(i==d_conntrack.end()) { | |
e6a9dde5 | 214 | g_log<<Logger::Error<<"Discarding untracked packet from recursor backend with id "<<(d.id^d_xor)<< |
abc1d928 | 215 | ". Conntrack table size="<<d_conntrack.size()<<endl; |
4957a608 BH |
216 | continue; |
217 | } | |
218 | else if(i->second.created==0) { | |
e6a9dde5 | 219 | g_log<<Logger::Error<<"Received packet from recursor backend with id "<<(d.id^d_xor)<<" which is a duplicate"<<endl; |
4957a608 BH |
220 | continue; |
221 | } | |
d59b894d | 222 | |
4957a608 BH |
223 | d.id=i->second.id; |
224 | memcpy(buffer,&d,sizeof(d)); // commit spoofed id | |
225 | ||
27c0050c | 226 | DNSPacket p(false),q(false); |
a683e8bd RG |
227 | p.parse(buffer,(size_t)len); |
228 | q.parse(buffer,(size_t)len); | |
7de6b0d5 BH |
229 | |
230 | if(p.qtype.getCode() != i->second.qtype || p.qdomain != i->second.qname) { | |
e6a9dde5 | 231 | g_log<<Logger::Error<<"Discarding packet from recursor backend with id "<<(d.id^d_xor)<< |
c348fec2 | 232 | ", qname or qtype mismatch ("<<p.qtype.getCode()<<" v " <<i->second.qtype<<", "<<p.qdomain<<" v "<<i->second.qname<<")"<<endl; |
7de6b0d5 BH |
233 | continue; |
234 | } | |
f5310162 | 235 | |
65d8e171 KN |
236 | /* Set up iov and msgh structures. */ |
237 | memset(&msgh, 0, sizeof(struct msghdr)); | |
d59b894d | 238 | string reply; // needs to be alive at time of sendmsg! |
239 | if(i->second.complete) { | |
240 | ||
27c0050c | 241 | MOADNSParser mdp(false, p.getString()); |
d59b894d | 242 | // cerr<<"Got completion, "<<mdp.d_answers.size()<<" answers, rcode: "<<mdp.d_header.rcode<<endl; |
243 | for(MOADNSParser::answers_t::const_iterator j=mdp.d_answers.begin(); j!=mdp.d_answers.end(); ++j) { | |
244 | // cerr<<"comp: "<<(int)j->first.d_place-1<<" "<<j->first.d_label<<" " << DNSRecordContent::NumberToType(j->first.d_type)<<" "<<j->first.d_content->getZoneRepresentation()<<endl; | |
e693ff5a | 245 | if(j->first.d_place == DNSResourceRecord::ANSWER || (j->first.d_place == DNSResourceRecord::AUTHORITY && j->first.d_type == QType::SOA)) { |
d59b894d | 246 | |
65d2032b | 247 | if(j->first.d_type == i->second.qtype || (i->second.qtype == QType::ANY && (j->first.d_type == QType::A || j->first.d_type == QType::AAAA))) { |
90ba52e0 | 248 | DNSZoneRecord dzr; |
249 | dzr.dr.d_name=i->second.aname; | |
250 | dzr.dr.d_type = j->first.d_type; | |
251 | dzr.dr.d_ttl=j->first.d_ttl; | |
252 | dzr.dr.d_place= j->first.d_place; | |
253 | dzr.dr.d_content=j->first.d_content; | |
254 | i->second.complete->addRecord(dzr); | |
d59b894d | 255 | } |
256 | } | |
257 | } | |
258 | i->second.complete->setRcode(mdp.d_header.rcode); | |
259 | reply=i->second.complete->getString(); | |
260 | iov.iov_base = (void*)reply.c_str(); | |
261 | iov.iov_len = reply.length(); | |
262 | delete i->second.complete; | |
263 | i->second.complete=0; | |
264 | } | |
265 | else { | |
266 | iov.iov_base = buffer; | |
267 | iov.iov_len = len; | |
268 | } | |
65d8e171 KN |
269 | msgh.msg_iov = &iov; |
270 | msgh.msg_iovlen = 1; | |
271 | msgh.msg_name = (struct sockaddr*)&i->second.remote; | |
272 | msgh.msg_namelen = i->second.remote.getSocklen(); | |
3eae691f | 273 | msgh.msg_control=NULL; |
65d8e171 KN |
274 | |
275 | if(i->second.anyLocal) { | |
fbe2a2e0 | 276 | addCMsgSrcAddr(&msgh, cbuf, i->second.anyLocal.get_ptr(), 0); |
f5310162 | 277 | } |
76511d0d | 278 | if(sendmsg(i->second.outsock, &msgh, 0) < 0) |
e6a9dde5 | 279 | g_log<<Logger::Warning<<"dnsproxy.cc: Error sending reply with sendmsg (socket="<<i->second.outsock<<"): "<<strerror(errno)<<endl; |
4957a608 | 280 | |
4957a608 | 281 | i->second.created=0; |
12c86877 BH |
282 | } |
283 | } | |
284 | } | |
3f81d239 | 285 | catch(PDNSException &ae) { |
e6a9dde5 | 286 | g_log<<Logger::Error<<"Fatal error in DNS proxy: "<<ae.reason<<endl; |
12c86877 | 287 | } |
adc10f99 | 288 | catch(std::exception &e) { |
e6a9dde5 | 289 | g_log<<Logger::Error<<"Communicator thread died because of STL error: "<<e.what()<<endl; |
12c86877 BH |
290 | } |
291 | catch( ... ) | |
292 | { | |
e6a9dde5 | 293 | g_log << Logger::Error << "Caught unknown exception." << endl; |
12c86877 | 294 | } |
e6a9dde5 | 295 | g_log<<Logger::Error<<"Exiting because DNS proxy failed"<<endl; |
5bd2ea7b | 296 | _exit(1); |
12c86877 | 297 | } |
732d9faa AT |
298 | |
299 | DNSProxy::~DNSProxy() { | |
a7b68ae7 RG |
300 | if (d_sock>-1) { |
301 | try { | |
302 | closesocket(d_sock); | |
303 | } | |
304 | catch(const PDNSException& e) { | |
305 | } | |
306 | } | |
307 | ||
732d9faa AT |
308 | d_sock=-1; |
309 | } |