/*
- * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
+ * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
*
* Squid software is distributed under GPLv2+ license and includes
* contributions from numerous individuals and organizations.
/* DEBUG: section 78 DNS lookups; interacts with dns/rfc1035.cc */
#include "squid.h"
+#include "base/CodeContext.h"
#include "base/InstanceId.h"
#include "base/RunnersRegistry.h"
#include "comm.h"
"Bad OPT Version or TSIG Signature Failure"
};
-typedef struct _ns ns;
-
typedef struct _sp sp;
class idns_query
CBDATA_CLASS(idns_query);
public:
- idns_query() {
+ idns_query():
+ codeContext(CodeContext::Current())
+ {
callback = nullptr;
memset(&query, 0, sizeof(query));
*buf = 0;
struct timeval sent_t;
struct timeval queue_t;
dlink_node lru;
+
IDNSCB *callback;
void *callback_data = nullptr;
+ CodeContext::Pointer codeContext; ///< requestor's context
+
int attempt = 0;
int rcode = 0;
idns_query *queue = nullptr;
CBDATA_CLASS(nsvc);
public:
- explicit nsvc(int nsv) : ns(nsv), msg(new MemBuf()), queue(new MemBuf()) {}
+ explicit nsvc(size_t nsv) : ns(nsv), msg(new MemBuf()), queue(new MemBuf()) {}
~nsvc();
- int ns = 0;
+ size_t ns = 0;
Comm::ConnectionPointer conn;
unsigned short msglen = 0;
int read_msglen = 0;
CBDATA_CLASS_INIT(nsvc);
-struct _ns {
+class ns
+{
+public:
Ip::Address S;
- int nqueries;
- int nreplies;
+ int nqueries = 0;
+ int nreplies = 0;
#if WHEN_EDNS_RESPONSES_ARE_PARSED
- int last_seen_edns;
+ int last_seen_edns = 0;
#endif
- bool mDNSResolver;
- nsvc *vc;
+ bool mDNSResolver = false;
+ nsvc *vc = nullptr;
};
namespace Dns
int queries;
};
-static ns *nameservers = NULL;
+static std::vector<ns> nameservers;
static sp *searchpath = NULL;
-static int nns = 0;
-static int nns_alloc = 0;
static int nns_mdns_count = 0;
static int npc = 0;
static int npc_alloc = 0;
static void idnsAddNameserver(const char *buf);
static void idnsAddMDNSNameservers();
static void idnsAddPathComponent(const char *buf);
-static void idnsFreeNameservers(void);
static void idnsFreeSearchpath(void);
static bool idnsParseNameservers(void);
static bool idnsParseResolvConf(void);
static CLCB idnsVCClosed;
static unsigned short idnsQueryID(void);
static void idnsSendSlaveAAAAQuery(idns_query *q);
+static void idnsCallbackOnEarlyError(IDNSCB *callback, void *cbdata, const char *error);
static void
idnsCheckMDNS(idns_query *q)
// mDNS resolver addresses are explicit multicast group IPs
if (Ip::EnableIpv6) {
idnsAddNameserver("FF02::FB");
- nameservers[nns-1].S.port(5353);
- nameservers[nns-1].mDNSResolver = true;
+ nameservers.back().S.port(5353);
+ nameservers.back().mDNSResolver = true;
++nns_mdns_count;
}
idnsAddNameserver("224.0.0.251");
- nameservers[nns-1].S.port(5353);
- nameservers[nns-1].mDNSResolver = true;
+ nameservers.back().S.port(5353);
+ nameservers.back().mDNSResolver = true;
++nns_mdns_count;
}
return;
}
- if (nns == nns_alloc) {
- int oldalloc = nns_alloc;
- ns *oldptr = nameservers;
-
- if (nns_alloc == 0)
- nns_alloc = 2;
- else
- nns_alloc <<= 1;
-
- nameservers = (ns *)xcalloc(nns_alloc, sizeof(*nameservers));
-
- if (oldptr && oldalloc)
- memcpy(nameservers, oldptr, oldalloc * sizeof(*nameservers));
-
- if (oldptr)
- safe_free(oldptr);
- }
-
- assert(nns < nns_alloc);
+ nameservers.emplace_back(ns());
A.port(NS_DEFAULTPORT);
- nameservers[nns].S = A;
+ nameservers.back().S = A;
#if WHEN_EDNS_RESPONSES_ARE_PARSED
- nameservers[nns].last_seen_edns = RFC1035_DEFAULT_PACKET_SZ;
+ nameservers.back().last_seen_edns = RFC1035_DEFAULT_PACKET_SZ;
// TODO generate a test packet to probe this NS from EDNS size and ability.
#endif
- debugs(78, 3, "idnsAddNameserver: Added nameserver #" << nns << " (" << A << ")");
- ++nns;
+ debugs(78, 3, "Added nameserver #" << nameservers.size()-1 << " (" << A << ")");
}
static void
++npc;
}
-static void
-idnsFreeNameservers(void)
-{
- safe_free(nameservers);
- nns = nns_alloc = 0;
-}
-
static void
idnsFreeSearchpath(void)
{
storeAppendPrintf(sentry, "IP ADDRESS # QUERIES # REPLIES Type\n");
storeAppendPrintf(sentry, "---------------------------------------------- --------- --------- --------\n");
- for (i = 0; i < nns; ++i) {
+ for (const auto &server : nameservers) {
storeAppendPrintf(sentry, "%-45s %9d %9d %s\n", /* Let's take the maximum: (15 IPv4/45 IPv6) */
- nameservers[i].S.toStr(buf,MAX_IPSTRLEN),
- nameservers[i].nqueries,
- nameservers[i].nreplies,
- nameservers[i].mDNSResolver?"multicast":"recurse");
+ server.S.toStr(buf,MAX_IPSTRLEN),
+ server.nqueries,
+ server.nreplies,
+ server.mDNSResolver?"multicast":"recurse");
}
storeAppendPrintf(sentry, "\nRcode Matrix:\n");
if (status != Comm::OK || !conn) {
char buf[MAX_IPSTRLEN] = "";
- if (vc->ns < nns)
+ if (vc->ns < nameservers.size())
nameservers[vc->ns].S.toStr(buf,MAX_IPSTRLEN);
debugs(78, DBG_IMPORTANT, HERE << "Failed to connect to nameserver " << buf << " using TCP.");
return;
{
delete queue;
delete msg;
- if (ns < nns) // XXX: idnsShutdownAndFreeState may have freed nameservers[]
+ if (ns < nameservers.size()) // XXX: idnsShutdownAndFreeState may have freed nameservers[]
nameservers[ns].vc = NULL;
}
static void
-idnsInitVC(int nsv)
+idnsInitVC(size_t nsv)
{
+ assert(nsv < nameservers.size());
nsvc *vc = new nsvc(nsv);
- assert(nsv < nns);
assert(vc->conn == NULL); // MUST be NULL from the construction process!
nameservers[nsv].vc = vc;
}
static void
-idnsSendQueryVC(idns_query * q, int nsn)
+idnsSendQueryVC(idns_query * q, size_t nsn)
{
- assert(nsn < nns);
+ assert(nsn < nameservers.size());
if (nameservers[nsn].vc == NULL)
idnsInitVC(nsn);
return;
}
- if (nns <= 0) {
+ if (nameservers.empty()) {
debugs(78, DBG_IMPORTANT, "WARNING: idnsSendQuery: Can't send query, no DNS nameservers known!");
return;
}
assert(q->lru.prev == NULL);
int x = -1, y = -1;
- int nsn;
+ size_t nsn;
+ const auto nsCount = nameservers.size();
do {
// only use mDNS resolvers for mDNS compatible queries
if (!q->permit_mdns)
- nsn = nns_mdns_count + q->nsends % (nns-nns_mdns_count);
+ nsn = nns_mdns_count + q->nsends % (nsCount - nns_mdns_count);
else
- nsn = q->nsends % nns;
+ nsn = q->nsends % nsCount;
if (q->need_vc) {
idnsSendQueryVC(q, nsn);
if (x < 0 && nameservers[nsn].S.isIPv4())
debugs(50, DBG_IMPORTANT, MYNAME << "FD " << DnsSocketA << ": sendto: " << xstrerr(xerrno));
- } while ( (x<0 && y<0) && q->nsends % nns != 0);
+ } while ( (x<0 && y<0) && q->nsends % nsCount != 0);
if (y > 0) {
fd_bytes(DnsSocketB, y, FD_WRITE);
static int
idnsFromKnownNameserver(Ip::Address const &from)
{
- int i;
-
- for (i = 0; i < nns; ++i) {
+ for (int i = 0; static_cast<size_t>(i) < nameservers.size(); ++i) {
if (nameservers[i].S != from)
continue;
return id;
}
-static void
-idnsCallback(idns_query *q, const char *error)
+/// \returns whether master or associated queries are still waiting for replies
+static bool
+idnsStillPending(const idns_query *master)
{
- IDNSCB *callback;
- void *cbdata;
+ assert(!master->master); // we were given the master transaction
+ for (const idns_query *qi = master; qi; qi = qi->slave) {
+ if (qi->pending)
+ return true;
+ }
+ return false;
+}
- if (error)
- q->error = error;
+static std::ostream &
+operator <<(std::ostream &os, const idns_query &answered)
+{
+ if (answered.error)
+ os << "error \"" << answered.error << "\"";
+ else
+ os << answered.ancount << " records";
+ return os;
+}
- if (q->master)
- q = q->master;
+static void
+idnsCallbackOnEarlyError(IDNSCB *callback, void *cbdata, const char *error)
+{
+ // A cbdataReferenceValid() check asserts on unlocked cbdata: Early errors,
+ // by definition, happen before we store/cbdataReference() cbdata.
+ debugs(78, 6, "\"" << error << "\" for " << cbdata);
+ callback(cbdata, nullptr, 0, "Internal error", true); // hide error details
+}
- // If any of our subqueries are still pending then wait for them to complete before continuing
- for (idns_query *q2 = q; q2; q2 = q2->slave) {
- if (q2->pending) {
- return;
- }
- }
+/// safely sends one set of DNS records (or an error) to the caller
+static bool
+idnsCallbackOneWithAnswer(IDNSCB *callback, void *cbdata, const idns_query &answered, const bool lastAnswer)
+{
+ if (!cbdataReferenceValid(cbdata))
+ return false;
+ const rfc1035_rr *records = answered.message ? answered.message->answer : nullptr;
+ debugs(78, 6, (lastAnswer ? "last " : "") << answered << " for " << cbdata);
+ callback(cbdata, records, answered.ancount, answered.error, lastAnswer);
+ return true;
+}
- /* Merge results */
- rfc1035_message *message = q->message;
- q->message = NULL;
- int n = q->ancount;
- error = q->error;
-
- while ( idns_query *q2 = q->slave ) {
- debugs(78, 6, HERE << "Merging DNS results " << q->name << " A has " << n << " RR, AAAA has " << q2->ancount << " RR");
- q->slave = q2->slave;
- q2->slave = NULL;
- if ( !q2->error ) {
- if (n > 0) {
- // two sets of RR need merging
- rfc1035_rr *result = (rfc1035_rr*) xmalloc( sizeof(rfc1035_rr)*(n + q2->ancount) );
- if (Config.dns.v4_first) {
- memcpy(result, message->answer, (sizeof(rfc1035_rr)*n) );
- memcpy(result+n, q2->message->answer, (sizeof(rfc1035_rr)*q2->ancount) );
- } else {
- memcpy(result, q2->message->answer, (sizeof(rfc1035_rr)*q2->ancount) );
- memcpy(result+q2->ancount, message->answer, (sizeof(rfc1035_rr)*n) );
- }
- n += q2->ancount;
- // HACK WARNING, the answer rr:s have been copied in-place to
- // result, do not free them here
- safe_free(message->answer);
- safe_free(q2->message->answer);
- message->answer = result;
- message->ancount += q2->message->ancount;
- } else {
- // first response empty or failed, just use the second
- rfc1035MessageDestroy(&message);
- message = q2->message;
- q2->message = NULL;
- n = q2->ancount;
- error = NULL;
- }
- }
- delete q2;
+static void
+idnsCallbackNewCallerWithOldAnswers(IDNSCB *callback, void *cbdata, const idns_query * const master)
+{
+ const bool lastAnswer = false;
+ // iterate all queries to act on answered ones
+ for (auto query = master; query; query = query->slave) {
+ if (query->pending)
+ continue; // no answer yet
+ // no CallBack(CodeContext...) -- we always run in requestor's context
+ if (!idnsCallbackOneWithAnswer(callback, cbdata, *query, lastAnswer))
+ break; // the caller disappeared
}
+}
- debugs(78, 6, HERE << "Sending " << n << " (" << (error ? error : "OK") << ") DNS results to caller.");
-
- callback = q->callback;
- q->callback = NULL;
- const rfc1035_rr *answers = message ? message->answer : NULL;
-
- if (cbdataReferenceValidDone(q->callback_data, &cbdata))
- callback(cbdata, answers, n, error);
+static void
+idnsCallbackAllCallersWithNewAnswer(const idns_query * const answered, const bool lastAnswer)
+{
+ debugs(78, 8, (lastAnswer ? "last " : "") << *answered);
+ const auto master = answered->master ? answered->master : answered;
+ // iterate all queued lookup callers
+ for (auto looker = master; looker; looker = looker->queue) {
+ CallBack(looker->codeContext, [&] {
+ (void)idnsCallbackOneWithAnswer(looker->callback, looker->callback_data,
+ *answered, lastAnswer);
+ });
+ }
+}
- while (q->queue) {
- idns_query *q2 = q->queue;
- q->queue = q2->queue;
- q2->queue = NULL;
+static void
+idnsCallback(idns_query *q, const char *error)
+{
+ if (error)
+ q->error = error;
- callback = q2->callback;
- q2->callback = NULL;
+ auto master = q->master ? q->master : q;
- if (cbdataReferenceValidDone(q2->callback_data, &cbdata))
- callback(cbdata, answers, n, error);
+ const bool lastAnswer = !idnsStillPending(master);
+ idnsCallbackAllCallersWithNewAnswer(q, lastAnswer);
- delete q2;
- }
+ if (!lastAnswer)
+ return; // wait for more answers
- if (q->hash.key) {
- hash_remove_link(idns_lookup_hash, &q->hash);
- q->hash.key = NULL;
+ if (master->hash.key) {
+ hash_remove_link(idns_lookup_hash, &master->hash);
+ master->hash.key = nullptr;
}
- rfc1035MessageDestroy(&message);
- delete q;
+ delete master;
}
static void
// the altered NS was limiting the whole group.
max_shared_edns = q->edns_seen;
// may be limited by one of the others still
- for (int i = 0; i < nns; ++i)
- max_shared_edns = min(max_shared_edns, nameservers[i].last_seen_edns);
+ for (const auto &server : nameservers)
+ max_shared_edns = min(max_shared_edns, server.last_seen_edns);
} else {
nameservers[from_ns].last_seen_edns = q->edns_seen;
// maybe reduce the global limit downwards to accomodate this NS
idns_query *q;
event_queued = 0;
- if (0 == nns)
+ if (nameservers.empty())
/* name servers went away; reconfiguring or shutting down */
return;
+ const auto nsCount = nameservers.size();
for (n = lru_list.tail; n; n = p) {
p = n->prev;
break;
/* Query timer still running? */
- if ((time_msec_t)tvSubMsec(q->sent_t, current_time) < (Config.Timeout.idns_retransmit * 1 << ((q->nsends - 1) / nns))) {
+ if ((time_msec_t)tvSubMsec(q->sent_t, current_time) < (Config.Timeout.idns_retransmit * 1 << ((q->nsends - 1) / nsCount))) {
dlinkDelete(&q->lru, &lru_list);
q->queue_t = current_time;
dlinkAdd(q, &q->lru, &lru_list);
return;
}
- assert(vc->ns < nns);
+ assert(vc->ns < nameservers.size());
debugs(78, 3, HERE << conn << ": received " << vc->msg->contentSize() << " bytes via TCP from " << nameservers[vc->ns].S << ".");
idnsGrokReply(vc->msg->buf, vc->msg->contentSize(), vc->ns);
static int init = 0;
if (DnsSocketA < 0 && DnsSocketB < 0) {
- Ip::Address addrV6; // since we don't want to alter Config.Addrs.udp_* and dont have one of our own.
+ Ip::Address addrV6; // since we do not want to alter Config.Addrs.udp_* and do not have one of our own.
if (!Config.Addrs.udp_outgoing.isNoAddr())
addrV6 = Config.Addrs.udp_outgoing;
}
}
- assert(0 == nns);
+ assert(nameservers.empty());
idnsAddMDNSNameservers();
bool nsFound = idnsParseNameservers();
DnsSocketB = -1;
}
- for (int i = 0; i < nns; ++i) {
- if (nsvc *vc = nameservers[i].vc) {
+ for (const auto &server : nameservers) {
+ if (const auto vc = server.vc) {
if (Comm::IsConnOpen(vc->conn))
vc->conn->close();
}
}
// XXX: vcs are not closed/freed yet and may try to access nameservers[]
- idnsFreeNameservers();
+ nameservers.clear();
idnsFreeSearchpath();
}
if (!old)
return 0;
+ // XXX: We are collapsing this DNS query (B) onto another one (A), but there
+ // is no code to later send B if the A answer has unshareable 0 TTL records.
+
idns_query *q = new idns_query;
// no query_id on this instance.
q->queue = old->queue;
old->queue = q;
+ // This check must follow cbdataReference() above because our callback code
+ // needs a locked cbdata to call cbdataReferenceValid().
+ if (idnsStillPending(old))
+ idnsCallbackNewCallerWithOldAnswers(callback, data, old);
+ // else: idns_lookup_hash is not a cache so no pending lookups means we are
+ // in a reentrant lookup and will be called back when dequeued.
+
return 1;
}
// Prevent buffer overflow on q->name
if (nameLength > NS_MAXDNAME) {
debugs(23, DBG_IMPORTANT, "SECURITY ALERT: DNS name too long to perform lookup: '" << name << "'. see access.log for details.");
- callback(data, NULL, 0, "Internal error");
+ idnsCallbackOnEarlyError(callback, data, "huge name");
return;
}
q->query_id = idnsQueryID();
int nd = 0;
- for (unsigned int i = 0; i < nameLength; ++i)
+ for (size_t i = 0; i < nameLength; ++i)
if (name[i] == '.')
++nd;
if (q->sz < 0) {
/* problem with query data -- query not sent */
- callback(data, NULL, 0, "Internal error");
+ idnsCallbackOnEarlyError(callback, data, "rfc3596BuildAQuery error");
delete q;
return;
}
if (q->sz < 0) {
/* problem with query data -- query not sent */
- callback(data, NULL, 0, "Internal error");
+ idnsCallbackOnEarlyError(callback, data, "rfc3596BuildPTRQuery error");
delete q;
return;
}
variable_list *
snmp_netDnsFn(variable_list * Var, snint * ErrP)
{
- int i, n = 0;
+ int n = 0;
variable_list *Answer = NULL;
MemBuf tmp;
debugs(49, 5, "snmp_netDnsFn: Processing request: " << snmpDebugOid(Var->name, Var->name_length, tmp));
case DNS_REQ:
- for (i = 0; i < nns; ++i)
- n += nameservers[i].nqueries;
+ for (const auto &server : nameservers)
+ n += server.nqueries;
Answer = snmp_var_new_integer(Var->name, Var->name_length,
n,
break;
case DNS_REP:
- for (i = 0; i < nns; ++i)
- n += nameservers[i].nreplies;
+ for (const auto &server : nameservers)
+ n += server.nreplies;
Answer = snmp_var_new_integer(Var->name, Var->name_length,
n,
case DNS_SERVERS:
Answer = snmp_var_new_integer(Var->name, Var->name_length,
- nns,
+ nameservers.size(),
SMI_COUNTER32);
break;
projects / thirdparty / squid.git / blobdiff