16615247828

Committed 30 Jul 2025 06:33AM UTC coverage: 65.845% (-0.03%) from 65.87%

Build # 16615247828

Build Type

Pull #15942

github

Committed by

web-flow

Commit Message

Merge 3e4243857 into 4a7b6a621

Pull Request Pull Request #15942: Optimize reload-zones logic to reduce thread scheduling times

Run Details

42051 of 92438 branches covered (45.49%)

Branch coverage included in aggregate %.

4 of 4 new or added lines in 1 file covered. (100.0%)

48 existing lines in 12 files now uncovered.

127942 of 165732 relevant lines covered (77.2%)

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77.02

/pdns/stubresolver.cc

#include <sys/stat.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "logger.hh"
#include "arguments.hh"
#include "version.hh"
#include "misc.hh"

#include "sstuff.hh"
#include "dnswriter.hh"
#include "dns_random.hh"
#include "namespaces.hh"
#include "statbag.hh"
#include "stubresolver.hh"
#include "ednsoptions.hh"
#include "ednssubnet.hh"

#define LOCAL_RESOLV_CONF_PATH "/etc/resolv.conf"
// don't stat() for local resolv.conf more than once every INTERVAL secs.
#define LOCAL_RESOLV_CONF_MAX_CHECK_INTERVAL 60

// s_resolversForStub contains the ComboAddresses that are used by
// stubDoResolve
static SharedLockGuarded<vector<ComboAddress>> s_resolversForStub;
static bool s_stubResolvConfigured = false;

// /etc/resolv.conf last modification time
static time_t s_localResolvConfMtime = 0;
static time_t s_localResolvConfLastCheck = 0;

static string logPrefix = "[stub-resolver] ";

/*
 * Returns false if no resolvers are configured, while emitting a warning about this
 */
bool resolversDefined()
{
  if (s_resolversForStub.read_lock()->empty()) {
    g_log << Logger::Warning << logPrefix << "No upstream resolvers configured, stub resolving (including secpoll and ALIAS) impossible." << endl;
    return false;
  }
  return true;
}

/*
 * Parse /etc/resolv.conf and add those nameservers to s_resolversForStub
 */
static void parseLocalResolvConf_locked(vector<ComboAddress>& resolversForStub, const time_t& now)
{
  struct stat statResult{};
  s_localResolvConfLastCheck = now;

  if (stat(LOCAL_RESOLV_CONF_PATH, &statResult) != -1) {
    if (statResult.st_mtime != s_localResolvConfMtime) {
      std::vector<ComboAddress> resolvers = getResolvers(LOCAL_RESOLV_CONF_PATH);

      s_localResolvConfMtime = statResult.st_mtime;

      if (resolvers.empty()) {
        return;
      }

      resolversForStub = std::move(resolvers);
    }
  }
}

static void parseLocalResolvConf()
{
  const time_t now = time(nullptr);
  if ((s_localResolvConfLastCheck + LOCAL_RESOLV_CONF_MAX_CHECK_INTERVAL) > now) {
    return;
  }

  parseLocalResolvConf_locked(*(s_resolversForStub.write_lock()), now);
}

/*
 * Fill the s_resolversForStub vector with addresses for the upstream resolvers.
 * First, parse the `resolver` configuration option for IP addresses to use.
 * If that doesn't work, parse /etc/resolv.conf and add those nameservers to
 * s_resolversForStub.
 *
 * mainthread() calls this so you don't have to.
 */
void stubParseResolveConf()
{
  if (::arg().mustDo("resolver")) {
    auto resolversForStub = s_resolversForStub.write_lock();
    vector<string> parts;
    stringtok(parts, ::arg()["resolver"], " ,\t");
    for (const auto& addr : parts) {
      resolversForStub->push_back(ComboAddress(addr, 53));
    }
  }

  if (s_resolversForStub.read_lock()->empty()) {
    parseLocalResolvConf();
  }
  // Emit a warning if there are no stubs.
  resolversDefined();
  s_stubResolvConfigured = true;
}

// s_resolversForStub contains the ComboAddresses that are used to resolve the
int stubDoResolve(const DNSName& qname, uint16_t qtype, vector<DNSZoneRecord>& ret, const EDNSSubnetOpts* d_eso)
{
  // ensure resolver gets always configured
  if (!s_stubResolvConfigured) {
    stubParseResolveConf();
  }
  // only check if resolvers come from local resolv.conf in the first place
  if (s_localResolvConfMtime != 0) {
    parseLocalResolvConf();
  }
  if (!resolversDefined()) {
    return RCode::ServFail;
  }

  auto resolversForStub = s_resolversForStub.read_lock();
  vector<uint8_t> packet;

  DNSPacketWriter packetWriter(packet, qname, qtype);
  packetWriter.getHeader()->id = dns_random_uint16();
  packetWriter.getHeader()->rd = 1;

  if (d_eso != nullptr) {
    // pass along EDNS subnet from client if given - issue #5469
    string origECSOptionStr = d_eso->makeOptString();
    DNSPacketWriter::optvect_t opts;
    opts.emplace_back(EDNSOptionCode::ECS, origECSOptionStr);
    packetWriter.addOpt(512, 0, 0, opts);
    packetWriter.commit();
  }

  string queryNameType = qname.toString() + "|" + QType(qtype).toString();
  string msg = "Doing stub resolving for '" + queryNameType + "', using resolvers: ";
  for (const auto& server : *resolversForStub) {
    msg += server.toString() + ", ";
  }
  g_log << Logger::Debug << logPrefix << msg.substr(0, msg.length() - 2) << endl;

  for (const ComboAddress& dest : *resolversForStub) {
    Socket sock(dest.sin4.sin_family, SOCK_DGRAM);
    sock.setNonBlocking();
    sock.connect(dest);
    sock.send(string(packet.begin(), packet.end()));

    string reply;

    // error handled after this
    (void)waitForData(sock.getHandle(), 2, 0);
    try {
    retry:
      sock.read(reply); // this calls recv
      if (reply.size() > sizeof(struct dnsheader)) {
        struct dnsheader dHeader{};
        memcpy(&dHeader, reply.c_str(), sizeof(dHeader));
        if (dHeader.id != packetWriter.getHeader()->id) {
          goto retry;
        }
      }
    }
    catch (...) {
      continue;
    }
    MOADNSParser mdp(false, reply);
    if (mdp.d_header.rcode == RCode::ServFail) {
      continue;
    }

    for (const auto& answer : mdp.d_answers) {
      if (answer.d_place == 1 && answer.d_type == qtype) {
        DNSZoneRecord zrr;
        zrr.dr = answer;
        zrr.auth = true;
        ret.push_back(zrr);
      }
    }
    g_log << Logger::Debug << logPrefix << "Question for '" << queryNameType << "' got answered by " << dest.toString() << endl;
    return mdp.d_header.rcode;
  }
  return RCode::ServFail;
}

int stubDoResolve(const DNSName& qname, uint16_t qtype, vector<DNSRecord>& ret, const EDNSSubnetOpts* d_eso)
{
  vector<DNSZoneRecord> ret2;
  int res = stubDoResolve(qname, qtype, ret2, d_eso);
  for (const auto& record : ret2) {
    ret.push_back(record.dr);
  }
  return res;
}

1	#include <sys/stat.h>
2
3	#ifdef HAVE_CONFIG_H
4	#include "config.h"
5	#endif
6
7	#include "logger.hh"
8	#include "arguments.hh"
9	#include "version.hh"
10	#include "misc.hh"
11
12	#include "sstuff.hh"
13	#include "dnswriter.hh"
14	#include "dns_random.hh"
15	#include "namespaces.hh"
16	#include "statbag.hh"
17	#include "stubresolver.hh"
18	#include "ednsoptions.hh"
19	#include "ednssubnet.hh"
20
21	#define LOCAL_RESOLV_CONF_PATH "/etc/resolv.conf"	178✔
22	// don't stat() for local resolv.conf more than once every INTERVAL secs.
23	#define LOCAL_RESOLV_CONF_MAX_CHECK_INTERVAL 60	178✔
24
25	// s_resolversForStub contains the ComboAddresses that are used by
26	// stubDoResolve
27	static SharedLockGuarded<vector<ComboAddress>> s_resolversForStub;
28	static bool s_stubResolvConfigured = false;
29
30	// /etc/resolv.conf last modification time
31	static time_t s_localResolvConfMtime = 0;
32	static time_t s_localResolvConfLastCheck = 0;
33
34	static string logPrefix = "[stub-resolver] ";
35
36	/*
37	* Returns false if no resolvers are configured, while emitting a warning about this
38	*/
39	bool resolversDefined()
40	{	520✔
41	if (s_resolversForStub.read_lock()->empty()) {	520!
42	g_log << Logger::Warning << logPrefix << "No upstream resolvers configured, stub resolving (including secpoll and ALIAS) impossible." << endl;	×
43	return false;	×
44	}	×
45	return true;	520✔
46	}	520✔
47
48	/*
49	* Parse /etc/resolv.conf and add those nameservers to s_resolversForStub
50	*/
51	static void parseLocalResolvConf_locked(vector<ComboAddress>& resolversForStub, const time_t& now)
52	{	89✔
53	struct stat statResult{};	89✔
54	s_localResolvConfLastCheck = now;	89✔
55
56	if (stat(LOCAL_RESOLV_CONF_PATH, &statResult) != -1) {	89!
57	if (statResult.st_mtime != s_localResolvConfMtime) {	89!
58	std::vector<ComboAddress> resolvers = getResolvers(LOCAL_RESOLV_CONF_PATH);	89✔
59
60	s_localResolvConfMtime = statResult.st_mtime;	89✔
61
62	if (resolvers.empty()) {	89!
63	return;	×
64	}	×
65
66	resolversForStub = std::move(resolvers);	89✔
67	}	89✔
68	}	89✔
69	}	89✔
70
71	static void parseLocalResolvConf()
72	{	178✔
73	const time_t now = time(nullptr);	178✔
74	if ((s_localResolvConfLastCheck + LOCAL_RESOLV_CONF_MAX_CHECK_INTERVAL) > now) {	178✔
75	return;	89✔
76	}	89✔
77
78	parseLocalResolvConf_locked(*(s_resolversForStub.write_lock()), now);	89✔
79	}	89✔
80
81	/*
82	* Fill the s_resolversForStub vector with addresses for the upstream resolvers.
83	* First, parse the `resolver` configuration option for IP addresses to use.
84	* If that doesn't work, parse /etc/resolv.conf and add those nameservers to
85	* s_resolversForStub.
86	*
87	* mainthread() calls this so you don't have to.
88	*/
89	void stubParseResolveConf()
90	{	172✔
91	if (::arg().mustDo("resolver")) {	172✔
92	auto resolversForStub = s_resolversForStub.write_lock();	83✔
93	vector<string> parts;	83✔
94	stringtok(parts, ::arg()["resolver"], " ,\t");	83✔
95	for (const auto& addr : parts) {	83✔
96	resolversForStub->push_back(ComboAddress(addr, 53));	83✔
97	}	83✔
98	}	83✔
99
100	if (s_resolversForStub.read_lock()->empty()) {	172✔
101	parseLocalResolvConf();	89✔
102	}	89✔
103	// Emit a warning if there are no stubs.
104	resolversDefined();	172✔
105	s_stubResolvConfigured = true;	172✔
106	}	172✔
107
108	// s_resolversForStub contains the ComboAddresses that are used to resolve the
109	int stubDoResolve(const DNSName& qname, uint16_t qtype, vector<DNSZoneRecord>& ret, const EDNSSubnetOpts* d_eso)
110	{	348✔
111	// ensure resolver gets always configured
112	if (!s_stubResolvConfigured) {	348!
113	stubParseResolveConf();	×
114	}	×
115	// only check if resolvers come from local resolv.conf in the first place
116	if (s_localResolvConfMtime != 0) {	348✔
117	parseLocalResolvConf();	89✔
118	}	89✔
119	if (!resolversDefined()) {	348!
120	return RCode::ServFail;	×
121	}	×
122
123	auto resolversForStub = s_resolversForStub.read_lock();	348✔
124	vector<uint8_t> packet;	348✔
125
126	DNSPacketWriter packetWriter(packet, qname, qtype);	348✔
127	packetWriter.getHeader()->id = dns_random_uint16();	348✔
128	packetWriter.getHeader()->rd = 1;	348✔
129
130	if (d_eso != nullptr) {	348!
131	// pass along EDNS subnet from client if given - issue #5469
132	string origECSOptionStr = d_eso->makeOptString();	×
133	DNSPacketWriter::optvect_t opts;	×
134	opts.emplace_back(EDNSOptionCode::ECS, origECSOptionStr);	×
135	packetWriter.addOpt(512, 0, 0, opts);	×
136	packetWriter.commit();	×
137	}	×
138
139	string queryNameType = qname.toString() + "\|" + QType(qtype).toString();	348✔
140	string msg = "Doing stub resolving for '" + queryNameType + "', using resolvers: ";	348✔
141	for (const auto& server : *resolversForStub) {	348✔
142	msg += server.toString() + ", ";	348✔
143	}	348✔
144	g_log << Logger::Debug << logPrefix << msg.substr(0, msg.length() - 2) << endl;	348✔
145
146	for (const ComboAddress& dest : *resolversForStub) {	348!
147	Socket sock(dest.sin4.sin_family, SOCK_DGRAM);	348✔
148	sock.setNonBlocking();	348✔
149	sock.connect(dest);	348✔
150	sock.send(string(packet.begin(), packet.end()));	348✔
151
152	string reply;	348✔
153
154	// error handled after this
155	(void)waitForData(sock.getHandle(), 2, 0);	348✔
156	try {	348✔
157	retry:	348✔
158	sock.read(reply); // this calls recv	348✔
159	if (reply.size() > sizeof(struct dnsheader)) {	348!
160	struct dnsheader dHeader{};	348✔
161	memcpy(&dHeader, reply.c_str(), sizeof(dHeader));	348✔
162	if (dHeader.id != packetWriter.getHeader()->id) {	348!
163	goto retry;	×
164	}	×
165	}	348✔
166	}	348✔
167	catch (...) {	348✔
UNCOV 168	continue;	×
UNCOV 169	}	×
170	MOADNSParser mdp(false, reply);	348✔
171	if (mdp.d_header.rcode == RCode::ServFail) {	348!
172	continue;	×
173	}	×
174
175	for (const auto& answer : mdp.d_answers) {	348✔
176	if (answer.d_place == 1 && answer.d_type == qtype) {	348!
177	DNSZoneRecord zrr;	176✔
178	zrr.dr = answer;	176✔
179	zrr.auth = true;	176✔
180	ret.push_back(zrr);	176✔
181	}	176✔
182	}	348✔
183	g_log << Logger::Debug << logPrefix << "Question for '" << queryNameType << "' got answered by " << dest.toString() << endl;	348✔
184	return mdp.d_header.rcode;	348✔
185	}	348✔
UNCOV 186	return RCode::ServFail;	×
187	}	348✔
188
189	int stubDoResolve(const DNSName& qname, uint16_t qtype, vector<DNSRecord>& ret, const EDNSSubnetOpts* d_eso)
190	{	172✔
191	vector<DNSZoneRecord> ret2;	172✔
192	int res = stubDoResolve(qname, qtype, ret2, d_eso);	172✔
193	for (const auto& record : ret2) {	172!
194	ret.push_back(record.dr);	×
195	}	×
196	return res;	172✔
197	}	172✔

PowerDNS / pdns / 16615247828

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