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7c673cae
FG
1// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
2// vim: ts=8 sw=2 smarttab
3/*
4 * Ceph - scalable distributed file system
5 *
6 * Copyright (C) 2016 SUSE LINUX GmbH
7 *
8 * This is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License version 2.1, as published by the Free Software
11 * Foundation. See file COPYING.
12 *
13 */
14
7c673cae 15#include <arpa/inet.h>
7c673cae 16
224ce89b 17#include "include/scope_guard.h"
7c673cae 18#include "dns_resolve.h"
7c673cae 19#include "common/debug.h"
7c673cae
FG
20
21#define dout_subsys ceph_subsys_
22
23using namespace std;
24
25namespace ceph {
26
27#ifdef HAVE_RES_NQUERY
28
29int ResolvHWrapper::res_nquery(res_state s, const char *hostname, int cls,
30 int type, u_char *buf, int bufsz) {
31 return ::res_nquery(s, hostname, cls, type, buf, bufsz);
32}
33
34int ResolvHWrapper::res_nsearch(res_state s, const char *hostname, int cls,
35 int type, u_char *buf, int bufsz) {
36 return ::res_nsearch(s, hostname, cls, type, buf, bufsz);
37}
38
39#else
40
41int ResolvHWrapper::res_query(const char *hostname, int cls,
42 int type, u_char *buf, int bufsz) {
43 return ::res_query(hostname, cls, type, buf, bufsz);
44}
45
46int ResolvHWrapper::res_search(const char *hostname, int cls,
47 int type, u_char *buf, int bufsz) {
48 return ::res_search(hostname, cls, type, buf, bufsz);
49}
50
51#endif
52
53DNSResolver::~DNSResolver()
54{
55#ifdef HAVE_RES_NQUERY
56 list<res_state>::iterator iter;
57 for (iter = states.begin(); iter != states.end(); ++iter) {
58 struct __res_state *s = *iter;
59 delete s;
60 }
61#endif
62 delete resolv_h;
63}
64
65#ifdef HAVE_RES_NQUERY
66int DNSResolver::get_state(CephContext *cct, res_state *ps)
67{
68 lock.Lock();
69 if (!states.empty()) {
70 res_state s = states.front();
71 states.pop_front();
72 lock.Unlock();
73 *ps = s;
74 return 0;
75 }
76 lock.Unlock();
77 struct __res_state *s = new struct __res_state;
78 s->options = 0;
79 if (res_ninit(s) < 0) {
80 delete s;
81 lderr(cct) << "ERROR: failed to call res_ninit()" << dendl;
82 return -EINVAL;
83 }
84 *ps = s;
85 return 0;
86}
87
88void DNSResolver::put_state(res_state s)
89{
90 Mutex::Locker l(lock);
91 states.push_back(s);
92}
93#endif
94
95int DNSResolver::resolve_cname(CephContext *cct, const string& hostname,
96 string *cname, bool *found)
97{
98 *found = false;
99
100#ifdef HAVE_RES_NQUERY
101 res_state res;
102 int r = get_state(cct, &res);
103 if (r < 0) {
104 return r;
105 }
224ce89b
WB
106 auto put_state = make_scope_guard([res, this] {
107 this->put_state(res);
108 });
7c673cae
FG
109#endif
110
7c673cae
FG
111#define LARGE_ENOUGH_DNS_BUFSIZE 1024
112 unsigned char buf[LARGE_ENOUGH_DNS_BUFSIZE];
113
114#define MAX_FQDN_SIZE 255
115 char host[MAX_FQDN_SIZE + 1];
116 const char *origname = hostname.c_str();
117 unsigned char *pt, *answer;
118 unsigned char *answend;
119 int len;
120
121#ifdef HAVE_RES_NQUERY
122 len = resolv_h->res_nquery(res, origname, ns_c_in, ns_t_cname, buf, sizeof(buf));
123#else
124 {
125# ifndef HAVE_THREAD_SAFE_RES_QUERY
126 Mutex::Locker l(lock);
127# endif
128 len = resolv_h->res_query(origname, ns_c_in, ns_t_cname, buf, sizeof(buf));
129 }
130#endif
131 if (len < 0) {
132 lderr(cct) << "res_query() failed" << dendl;
224ce89b 133 return 0;
7c673cae
FG
134 }
135
136 answer = buf;
137 pt = answer + NS_HFIXEDSZ;
138 answend = answer + len;
139
140 /* read query */
141 if ((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
142 lderr(cct) << "ERROR: dn_expand() failed" << dendl;
224ce89b 143 return -EINVAL;
7c673cae
FG
144 }
145 pt += len;
146
147 if (pt + 4 > answend) {
148 lderr(cct) << "ERROR: bad reply" << dendl;
224ce89b 149 return -EIO;
7c673cae
FG
150 }
151
152 int type;
153 NS_GET16(type, pt);
154
155 if (type != ns_t_cname) {
156 lderr(cct) << "ERROR: failed response type: type=" << type <<
157 " (was expecting " << ns_t_cname << ")" << dendl;
224ce89b 158 return -EIO;
7c673cae
FG
159 }
160
161 pt += NS_INT16SZ; /* class */
162
163 /* read answer */
164 if ((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
224ce89b 165 return 0;
7c673cae
FG
166 }
167 pt += len;
168 ldout(cct, 20) << "name=" << host << dendl;
169
170 if (pt + 10 > answend) {
171 lderr(cct) << "ERROR: bad reply" << dendl;
224ce89b 172 return -EIO;
7c673cae
FG
173 }
174
175 NS_GET16(type, pt);
176 pt += NS_INT16SZ; /* class */
177 pt += NS_INT32SZ; /* ttl */
178 pt += NS_INT16SZ; /* size */
179
180 if ((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
224ce89b 181 return 0;
7c673cae
FG
182 }
183 ldout(cct, 20) << "cname host=" << host << dendl;
184 *cname = host;
185
186 *found = true;
224ce89b 187 return 0;
7c673cae
FG
188}
189
190
191int DNSResolver::resolve_ip_addr(CephContext *cct, const string& hostname,
192 entity_addr_t *addr) {
193
194#ifdef HAVE_RES_NQUERY
195 res_state res;
196 int r = get_state(cct, &res);
197 if (r < 0) {
198 return r;
199 }
b32b8144
FG
200 auto put_state = make_scope_guard([res, this] {
201 this->put_state(res);
202 });
7c673cae
FG
203 return this->resolve_ip_addr(cct, &res, hostname, addr);
204#else
205 return this->resolve_ip_addr(cct, NULL, hostname, addr);
206#endif
207
208}
209
210int DNSResolver::resolve_ip_addr(CephContext *cct, res_state *res, const string& hostname,
211 entity_addr_t *addr) {
212
213 u_char nsbuf[NS_PACKETSZ];
214 int len;
215
216
217#ifdef HAVE_RES_NQUERY
218 len = resolv_h->res_nquery(*res, hostname.c_str(), ns_c_in, ns_t_a, nsbuf, sizeof(nsbuf));
219#else
220 {
221# ifndef HAVE_THREAD_SAFE_RES_QUERY
222 Mutex::Locker l(lock);
223# endif
224 len = resolv_h->res_query(hostname.c_str(), ns_c_in, ns_t_a, nsbuf, sizeof(nsbuf));
225 }
226#endif
227 if (len < 0) {
228 lderr(cct) << "res_query() failed" << dendl;
229 return len;
230 }
231 else if (len == 0) {
232 ldout(cct, 20) << "no address found for hostname " << hostname << dendl;
233 return -1;
234 }
235
236 ns_msg handle;
237 ns_initparse(nsbuf, len, &handle);
238
239 if (ns_msg_count(handle, ns_s_an) == 0) {
240 ldout(cct, 20) << "no address found for hostname " << hostname << dendl;
241 return -1;
242 }
243
244 ns_rr rr;
245 int r;
246 if ((r = ns_parserr(&handle, ns_s_an, 0, &rr)) < 0) {
247 lderr(cct) << "error while parsing DNS record" << dendl;
248 return r;
249 }
250
251 char addr_buf[64];
252 memset(addr_buf, 0, sizeof(addr_buf));
253 inet_ntop(AF_INET, ns_rr_rdata(rr), addr_buf, sizeof(addr_buf));
254 if (!addr->parse(addr_buf)) {
255 lderr(cct) << "failed to parse address '" << (const char *)ns_rr_rdata(rr)
256 << "'" << dendl;
257 return -1;
258 }
259
260 return 0;
261}
262
263int DNSResolver::resolve_srv_hosts(CephContext *cct, const string& service_name,
224ce89b
WB
264 const SRV_Protocol trans_protocol,
265 map<string, DNSResolver::Record> *srv_hosts) {
7c673cae
FG
266 return this->resolve_srv_hosts(cct, service_name, trans_protocol, "", srv_hosts);
267}
268
269int DNSResolver::resolve_srv_hosts(CephContext *cct, const string& service_name,
270 const SRV_Protocol trans_protocol, const string& domain,
224ce89b 271 map<string, DNSResolver::Record> *srv_hosts) {
7c673cae
FG
272
273#ifdef HAVE_RES_NQUERY
274 res_state res;
275 int r = get_state(cct, &res);
276 if (r < 0) {
277 return r;
278 }
224ce89b
WB
279 auto put_state = make_scope_guard([res, this] {
280 this->put_state(res);
281 });
7c673cae
FG
282#endif
283
7c673cae
FG
284 u_char nsbuf[NS_PACKETSZ];
285 int num_hosts;
286
287 string proto_str = srv_protocol_to_str(trans_protocol);
288 string query_str = "_"+service_name+"._"+proto_str+(domain.empty() ? ""
289 : "."+domain);
290 int len;
291
292#ifdef HAVE_RES_NQUERY
293 len = resolv_h->res_nsearch(res, query_str.c_str(), ns_c_in, ns_t_srv, nsbuf,
294 sizeof(nsbuf));
295#else
296 {
297# ifndef HAVE_THREAD_SAFE_RES_QUERY
298 Mutex::Locker l(lock);
299# endif
300 len = resolv_h->res_search(query_str.c_str(), ns_c_in, ns_t_srv, nsbuf,
301 sizeof(nsbuf));
302 }
303#endif
304 if (len < 0) {
224ce89b
WB
305 lderr(cct) << "failed for service " << query_str << dendl;
306 return len;
7c673cae
FG
307 }
308 else if (len == 0) {
309 ldout(cct, 20) << "No hosts found for service " << query_str << dendl;
224ce89b 310 return 0;
7c673cae
FG
311 }
312
313 ns_msg handle;
314
315 ns_initparse(nsbuf, len, &handle);
316
317 num_hosts = ns_msg_count (handle, ns_s_an);
318 if (num_hosts == 0) {
319 ldout(cct, 20) << "No hosts found for service " << query_str << dendl;
224ce89b 320 return 0;
7c673cae
FG
321 }
322
323 ns_rr rr;
324 char full_target[NS_MAXDNAME];
325
326 for (int i = 0; i < num_hosts; i++) {
327 int r;
328 if ((r = ns_parserr(&handle, ns_s_an, i, &rr)) < 0) {
329 lderr(cct) << "Error while parsing DNS record" << dendl;
224ce89b 330 return r;
7c673cae
FG
331 }
332
333 string full_srv_name = ns_rr_name(rr);
334 string protocol = "_" + proto_str;
335 string srv_domain = full_srv_name.substr(full_srv_name.find(protocol)
336 + protocol.length());
337
224ce89b
WB
338 auto rdata = ns_rr_rdata(rr);
339 uint16_t priority = ns_get16(rdata); rdata += NS_INT16SZ;
340 rdata += NS_INT16SZ; // weight
341 uint16_t port = ns_get16(rdata); rdata += NS_INT16SZ;
7c673cae
FG
342 memset(full_target, 0, sizeof(full_target));
343 ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
224ce89b 344 rdata, full_target, sizeof(full_target));
7c673cae
FG
345
346 entity_addr_t addr;
347#ifdef HAVE_RES_NQUERY
348 r = this->resolve_ip_addr(cct, &res, full_target, &addr);
349#else
350 r = this->resolve_ip_addr(cct, NULL, full_target, &addr);
351#endif
352
353 if (r == 0) {
354 addr.set_port(port);
355 string target = full_target;
224ce89b
WB
356 auto end = target.find(srv_domain);
357 if (end == target.npos) {
358 lderr(cct) << "resolved target not in search domain: "
359 << target << " / " << srv_domain << dendl;
360 return -EINVAL;
361 }
362 target = target.substr(0, end);
363 (*srv_hosts)[target] = {priority, addr};
7c673cae 364 }
7c673cae 365 }
224ce89b 366 return 0;
7c673cae
FG
367}
368
369}