[ceph.git] / ceph / src / common / dns_resolve.cc

// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
 * Ceph - scalable distributed file system
 *
 * Copyright (C) 2016 SUSE LINUX GmbH
 *
 * This is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software
 * Foundation.  See file COPYING.
 *
 */

#include <arpa/inet.h>

#include "include/scope_guard.h"
#include "dns_resolve.h"
#include "common/debug.h"

#define dout_subsys ceph_subsys_

using namespace std;

namespace ceph {

#ifdef HAVE_RES_NQUERY

int ResolvHWrapper::res_nquery(res_state s, const char *hostname, int cls,
    int type, u_char *buf, int bufsz) {
  return ::res_nquery(s, hostname, cls, type, buf, bufsz);
}

int ResolvHWrapper::res_nsearch(res_state s, const char *hostname, int cls,
    int type, u_char *buf, int bufsz) {
  return ::res_nsearch(s, hostname, cls, type, buf, bufsz);
}

#else

int ResolvHWrapper::res_query(const char *hostname, int cls,
    int type, u_char *buf, int bufsz) {
  return ::res_query(hostname, cls, type, buf, bufsz);
}

int ResolvHWrapper::res_search(const char *hostname, int cls,
    int type, u_char *buf, int bufsz) {
  return ::res_search(hostname, cls, type, buf, bufsz);
}

#endif

DNSResolver::~DNSResolver()
{
#ifdef HAVE_RES_NQUERY
  list<res_state>::iterator iter;
  for (iter = states.begin(); iter != states.end(); ++iter) {
    struct __res_state *s = *iter;
    delete s;
  }
#endif
  delete resolv_h;
}

#ifdef HAVE_RES_NQUERY
int DNSResolver::get_state(CephContext *cct, res_state *ps)
{
  lock.Lock();
  if (!states.empty()) {
    res_state s = states.front();
    states.pop_front();
    lock.Unlock();
    *ps = s;
    return 0;
  }
  lock.Unlock();
  struct __res_state *s = new struct __res_state;
  s->options = 0;
  if (res_ninit(s) < 0) {
    delete s;
    lderr(cct) << "ERROR: failed to call res_ninit()" << dendl;
    return -EINVAL;
  }
  *ps = s;
  return 0;
}

void DNSResolver::put_state(res_state s)
{
  Mutex::Locker l(lock);
  states.push_back(s);
}
#endif

int DNSResolver::resolve_cname(CephContext *cct, const string& hostname,
    string *cname, bool *found)
{
  *found = false;

#ifdef HAVE_RES_NQUERY
  res_state res;
  int r = get_state(cct, &res);
  if (r < 0) {
    return r;
  }
  auto put_state = make_scope_guard([res, this] {
      this->put_state(res);
    });
#endif

#define LARGE_ENOUGH_DNS_BUFSIZE 1024
  unsigned char buf[LARGE_ENOUGH_DNS_BUFSIZE];

#define MAX_FQDN_SIZE 255
  char host[MAX_FQDN_SIZE + 1];
  const char *origname = hostname.c_str();
  unsigned char *pt, *answer;
  unsigned char *answend;
  int len;

#ifdef HAVE_RES_NQUERY
  len = resolv_h->res_nquery(res, origname, ns_c_in, ns_t_cname, buf, sizeof(buf));
#else
  {
# ifndef HAVE_THREAD_SAFE_RES_QUERY
    Mutex::Locker l(lock);
# endif
    len = resolv_h->res_query(origname, ns_c_in, ns_t_cname, buf, sizeof(buf));
  }
#endif
  if (len < 0) {
    lderr(cct) << "res_query() failed" << dendl;
    return 0;
  }

  answer = buf;
  pt = answer + NS_HFIXEDSZ;
  answend = answer + len;

  /* read query */
  if ((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
    lderr(cct) << "ERROR: dn_expand() failed" << dendl;
    return -EINVAL;
  }
  pt += len;

  if (pt + 4 > answend) {
    lderr(cct) << "ERROR: bad reply" << dendl;
    return -EIO;
  }

  int type;
  NS_GET16(type, pt);

  if (type != ns_t_cname) {
    lderr(cct) << "ERROR: failed response type: type=" << type <<
      " (was expecting " << ns_t_cname << ")" << dendl;
    return -EIO;
  }

  pt += NS_INT16SZ; /* class */

  /* read answer */
  if ((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
    return 0;
  }
  pt += len;
  ldout(cct, 20) << "name=" << host << dendl;

  if (pt + 10 > answend) {
    lderr(cct) << "ERROR: bad reply" << dendl;
    return -EIO;
  }

  NS_GET16(type, pt);
  pt += NS_INT16SZ; /* class */
  pt += NS_INT32SZ; /* ttl */
  pt += NS_INT16SZ; /* size */

  if ((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
    return 0;
  }
  ldout(cct, 20) << "cname host=" << host << dendl;
  *cname = host;

  *found = true;
  return 0;
}


int DNSResolver::resolve_ip_addr(CephContext *cct, const string& hostname,
    entity_addr_t *addr) {

#ifdef HAVE_RES_NQUERY
  res_state res;
  int r = get_state(cct, &res);
  if (r < 0) {
    return r;
  }
  return this->resolve_ip_addr(cct, &res, hostname, addr);
#else
  return this->resolve_ip_addr(cct, NULL, hostname, addr);
#endif

}

int DNSResolver::resolve_ip_addr(CephContext *cct, res_state *res, const string& hostname, 
    entity_addr_t *addr) {

  u_char nsbuf[NS_PACKETSZ];
  int len;


#ifdef HAVE_RES_NQUERY
  len = resolv_h->res_nquery(*res, hostname.c_str(), ns_c_in, ns_t_a, nsbuf, sizeof(nsbuf));
#else
  {
# ifndef HAVE_THREAD_SAFE_RES_QUERY
    Mutex::Locker l(lock);
# endif
    len = resolv_h->res_query(hostname.c_str(), ns_c_in, ns_t_a, nsbuf, sizeof(nsbuf));
  }
#endif
  if (len < 0) {
    lderr(cct) << "res_query() failed" << dendl;
    return len;
  }
  else if (len == 0) {
    ldout(cct, 20) << "no address found for hostname " << hostname << dendl;
    return -1;
  }

  ns_msg handle;
  ns_initparse(nsbuf, len, &handle);

  if (ns_msg_count(handle, ns_s_an) == 0) {
    ldout(cct, 20) << "no address found for hostname " << hostname << dendl;
    return -1;
  }

  ns_rr rr;
  int r;
  if ((r = ns_parserr(&handle, ns_s_an, 0, &rr)) < 0) {
      lderr(cct) << "error while parsing DNS record" << dendl;
      return r;
  }

  char addr_buf[64];
  memset(addr_buf, 0, sizeof(addr_buf));
  inet_ntop(AF_INET, ns_rr_rdata(rr), addr_buf, sizeof(addr_buf));
  if (!addr->parse(addr_buf)) {
      lderr(cct) << "failed to parse address '" << (const char *)ns_rr_rdata(rr) 
        << "'" << dendl;
      return -1;
  }

  return 0;
}

int DNSResolver::resolve_srv_hosts(CephContext *cct, const string& service_name, 
    const SRV_Protocol trans_protocol,
    map<string, DNSResolver::Record> *srv_hosts) {
  return this->resolve_srv_hosts(cct, service_name, trans_protocol, "", srv_hosts);
}

int DNSResolver::resolve_srv_hosts(CephContext *cct, const string& service_name, 
    const SRV_Protocol trans_protocol, const string& domain,
    map<string, DNSResolver::Record> *srv_hosts) {

#ifdef HAVE_RES_NQUERY
  res_state res;
  int r = get_state(cct, &res);
  if (r < 0) {
    return r;
  }
  auto put_state = make_scope_guard([res, this] {
      this->put_state(res);
    });
#endif

  u_char nsbuf[NS_PACKETSZ];
  int num_hosts;

  string proto_str = srv_protocol_to_str(trans_protocol);
  string query_str = "_"+service_name+"._"+proto_str+(domain.empty() ? ""
      : "."+domain);
  int len;

#ifdef HAVE_RES_NQUERY
  len = resolv_h->res_nsearch(res, query_str.c_str(), ns_c_in, ns_t_srv, nsbuf,
      sizeof(nsbuf));
#else
  {
# ifndef HAVE_THREAD_SAFE_RES_QUERY
    Mutex::Locker l(lock);
# endif
    len = resolv_h->res_search(query_str.c_str(), ns_c_in, ns_t_srv, nsbuf,
        sizeof(nsbuf));
  }
#endif
  if (len < 0) {
    lderr(cct) << "failed for service " << query_str << dendl;
    return len;
  }
  else if (len == 0) {
    ldout(cct, 20) << "No hosts found for service " << query_str << dendl;
    return 0;
  }

  ns_msg handle;

  ns_initparse(nsbuf, len, &handle);

  num_hosts = ns_msg_count (handle, ns_s_an);
  if (num_hosts == 0) {
    ldout(cct, 20) << "No hosts found for service " << query_str << dendl;
    return 0;
  }

  ns_rr rr;
  char full_target[NS_MAXDNAME];

  for (int i = 0; i < num_hosts; i++) {
    int r;
    if ((r = ns_parserr(&handle, ns_s_an, i, &rr)) < 0) {
      lderr(cct) << "Error while parsing DNS record" << dendl;
      return r;
    }

    string full_srv_name = ns_rr_name(rr);
    string protocol = "_" + proto_str;
    string srv_domain = full_srv_name.substr(full_srv_name.find(protocol)
        + protocol.length());

    auto rdata = ns_rr_rdata(rr);
    uint16_t priority = ns_get16(rdata); rdata += NS_INT16SZ;
    rdata += NS_INT16SZ;	// weight
    uint16_t port = ns_get16(rdata); rdata += NS_INT16SZ;
    memset(full_target, 0, sizeof(full_target));
    ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
                       rdata, full_target, sizeof(full_target));

    entity_addr_t addr;
#ifdef HAVE_RES_NQUERY
    r = this->resolve_ip_addr(cct, &res, full_target, &addr);
#else
    r = this->resolve_ip_addr(cct, NULL, full_target, &addr);
#endif

    if (r == 0) {
      addr.set_port(port);
      string target = full_target;
      auto end = target.find(srv_domain);
      if (end == target.npos) {
	lderr(cct) << "resolved target not in search domain: "
		   << target << " / " << srv_domain << dendl;
	return -EINVAL;
      }
      target = target.substr(0, end);
      (*srv_hosts)[target] = {priority, addr};
    }
  }
  return 0;
}

}
Commit	Line	Data
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
	23	using namespace std;
	24
	25	namespace ceph {
	26
	27	#ifdef HAVE_RES_NQUERY
	28
	29	int 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
	34	int 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
	41	int 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
	46	int 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
	53	DNSResolver::~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
	66	int 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
88	void DNSResolver::put_state(res_state s)
89	{
90	Mutex::Locker l(lock);
91	states.push_back(s);
92	}
93	#endif
94
95	int 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
7c673cae FG	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
	191	int 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	}
	200	return this->resolve_ip_addr(cct, &res, hostname, addr);
	201	#else
	202	return this->resolve_ip_addr(cct, NULL, hostname, addr);
	203	#endif
	204
	205	}
	206
	207	int DNSResolver::resolve_ip_addr(CephContext cct, res_state res, const string& hostname,
	208	entity_addr_t *addr) {
	209
	210	u_char nsbuf[NS_PACKETSZ];
	211	int len;
	212
	213
	214	#ifdef HAVE_RES_NQUERY
	215	len = resolv_h->res_nquery(*res, hostname.c_str(), ns_c_in, ns_t_a, nsbuf, sizeof(nsbuf));
	216	#else
	217	{
	218	# ifndef HAVE_THREAD_SAFE_RES_QUERY
	219	Mutex::Locker l(lock);
	220	# endif
	221	len = resolv_h->res_query(hostname.c_str(), ns_c_in, ns_t_a, nsbuf, sizeof(nsbuf));
	222	}
	223	#endif
	224	if (len < 0) {
	225	lderr(cct) << "res_query() failed" << dendl;
	226	return len;
	227	}
	228	else if (len == 0) {
	229	ldout(cct, 20) << "no address found for hostname " << hostname << dendl;
	230	return -1;
	231	}
	232
	233	ns_msg handle;
	234	ns_initparse(nsbuf, len, &handle);
	235
	236	if (ns_msg_count(handle, ns_s_an) == 0) {
	237	ldout(cct, 20) << "no address found for hostname " << hostname << dendl;
	238	return -1;
	239	}
	240
	241	ns_rr rr;
	242	int r;
	243	if ((r = ns_parserr(&handle, ns_s_an, 0, &rr)) < 0) {
	244	lderr(cct) << "error while parsing DNS record" << dendl;
	245	return r;
	246	}
	247
	248	char addr_buf[64];
	249	memset(addr_buf, 0, sizeof(addr_buf));
	250	inet_ntop(AF_INET, ns_rr_rdata(rr), addr_buf, sizeof(addr_buf));
	251	if (!addr->parse(addr_buf)) {
252	lderr(cct) << "failed to parse address '" << (const char *)ns_rr_rdata(rr)
253	<< "'" << dendl;
254	return -1;
255	}
256
257	return 0;
258	}
259
260	int DNSResolver::resolve_srv_hosts(CephContext *cct, const string& service_name,
224ce89b WB	261	const SRV_Protocol trans_protocol,
224ce89b WB	262	map<string, DNSResolver::Record> *srv_hosts) {
7c673cae FG	263	return this->resolve_srv_hosts(cct, service_name, trans_protocol, "", srv_hosts);
	264	}
	265
	266	int DNSResolver::resolve_srv_hosts(CephContext *cct, const string& service_name,
	267	const SRV_Protocol trans_protocol, const string& domain,
224ce89b	268	map<string, DNSResolver::Record> *srv_hosts) {
7c673cae FG	269
	270	#ifdef HAVE_RES_NQUERY
	271	res_state res;
	272	int r = get_state(cct, &res);
	273	if (r < 0) {
	274	return r;
	275	}
224ce89b WB	276	auto put_state = make_scope_guard([res, this] {
	277	this->put_state(res);
	278	});
7c673cae FG	279	#endif
7c673cae FG	280
7c673cae FG	281	u_char nsbuf[NS_PACKETSZ];
	282	int num_hosts;
	283
	284	string proto_str = srv_protocol_to_str(trans_protocol);
	285	string query_str = "_"+service_name+"._"+proto_str+(domain.empty() ? ""
	286	: "."+domain);
	287	int len;
	288
	289	#ifdef HAVE_RES_NQUERY
	290	len = resolv_h->res_nsearch(res, query_str.c_str(), ns_c_in, ns_t_srv, nsbuf,
	291	sizeof(nsbuf));
	292	#else
	293	{
	294	# ifndef HAVE_THREAD_SAFE_RES_QUERY
	295	Mutex::Locker l(lock);
	296	# endif
	297	len = resolv_h->res_search(query_str.c_str(), ns_c_in, ns_t_srv, nsbuf,
	298	sizeof(nsbuf));
	299	}
	300	#endif
	301	if (len < 0) {
224ce89b WB	302	lderr(cct) << "failed for service " << query_str << dendl;
224ce89b WB	303	return len;
7c673cae FG	304	}
	305	else if (len == 0) {
	306	ldout(cct, 20) << "No hosts found for service " << query_str << dendl;
224ce89b	307	return 0;
7c673cae FG	308	}
	309
	310	ns_msg handle;
	311
	312	ns_initparse(nsbuf, len, &handle);
	313
	314	num_hosts = ns_msg_count (handle, ns_s_an);
	315	if (num_hosts == 0) {
	316	ldout(cct, 20) << "No hosts found for service " << query_str << dendl;
224ce89b	317	return 0;
7c673cae FG	318	}
	319
	320	ns_rr rr;
	321	char full_target[NS_MAXDNAME];
	322
	323	for (int i = 0; i < num_hosts; i++) {
	324	int r;
	325	if ((r = ns_parserr(&handle, ns_s_an, i, &rr)) < 0) {
	326	lderr(cct) << "Error while parsing DNS record" << dendl;
224ce89b	327	return r;
7c673cae FG	328	}
	329
	330	string full_srv_name = ns_rr_name(rr);
	331	string protocol = "_" + proto_str;
	332	string srv_domain = full_srv_name.substr(full_srv_name.find(protocol)
	333	+ protocol.length());
	334
224ce89b WB	335	auto rdata = ns_rr_rdata(rr);
	336	uint16_t priority = ns_get16(rdata); rdata += NS_INT16SZ;
	337	rdata += NS_INT16SZ; // weight
	338	uint16_t port = ns_get16(rdata); rdata += NS_INT16SZ;
7c673cae FG	339	memset(full_target, 0, sizeof(full_target));
7c673cae FG	340	ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
224ce89b	341	rdata, full_target, sizeof(full_target));
7c673cae FG	342
	343	entity_addr_t addr;
	344	#ifdef HAVE_RES_NQUERY
	345	r = this->resolve_ip_addr(cct, &res, full_target, &addr);
	346	#else
	347	r = this->resolve_ip_addr(cct, NULL, full_target, &addr);
	348	#endif
	349
	350	if (r == 0) {
	351	addr.set_port(port);
	352	string target = full_target;
224ce89b WB	353	auto end = target.find(srv_domain);
	354	if (end == target.npos) {
	355	lderr(cct) << "resolved target not in search domain: "
	356	<< target << " / " << srv_domain << dendl;
	357	return -EINVAL;
	358	}
	359	target = target.substr(0, end);
	360	(*srv_hosts)[target] = {priority, addr};
7c673cae	361	}
7c673cae	362	}
224ce89b	363	return 0;
7c673cae FG	364	}
	365
	366	}