1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790
|
/*
* This file is part of PowerDNS or dnsdist.
* Copyright -- PowerDNS.COM B.V. and its contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* In addition, for the avoidance of any doubt, permission is granted to
* link this program with OpenSSL and to (re)distribute the binaries
* produced as the result of such linking.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "dnsdist.hh"
#include "dnsdist-ecs.hh"
#include "dnsdist-rings.hh"
#include "dnsdist-xpf.hh"
#include "dnsparser.hh"
#include "ednsoptions.hh"
#include "dolog.hh"
#include "lock.hh"
#include "gettime.hh"
#include "tcpiohandler.hh"
#include "threadname.hh"
#include <thread>
#include <atomic>
#include <netinet/tcp.h>
using std::thread;
using std::atomic;
/* TCP: the grand design.
We forward 'messages' between clients and downstream servers. Messages are 65k bytes large, tops.
An answer might theoretically consist of multiple messages (for example, in the case of AXFR), initially
we will not go there.
In a sense there is a strong symmetry between UDP and TCP, once a connection to a downstream has been setup.
This symmetry is broken because of head-of-line blocking within TCP though, necessitating additional connections
to guarantee performance.
So the idea is to have a 'pool' of available downstream connections, and forward messages to/from them and never queue.
So whenever an answer comes in, we know where it needs to go.
Let's start naively.
*/
static int setupTCPDownstream(shared_ptr<DownstreamState> ds, uint16_t& downstreamFailures)
{
do {
vinfolog("TCP connecting to downstream %s (%d)", ds->remote.toStringWithPort(), downstreamFailures);
int sock = SSocket(ds->remote.sin4.sin_family, SOCK_STREAM, 0);
try {
if (!IsAnyAddress(ds->sourceAddr)) {
SSetsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 1);
#ifdef IP_BIND_ADDRESS_NO_PORT
if (ds->ipBindAddrNoPort) {
SSetsockopt(sock, SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
}
#endif
SBind(sock, ds->sourceAddr);
}
setNonBlocking(sock);
#ifdef MSG_FASTOPEN
if (!ds->tcpFastOpen) {
SConnectWithTimeout(sock, ds->remote, ds->tcpConnectTimeout);
}
#else
SConnectWithTimeout(sock, ds->remote, ds->tcpConnectTimeout);
#endif /* MSG_FASTOPEN */
return sock;
}
catch(const std::runtime_error& e) {
/* don't leak our file descriptor if SConnect() (for example) throws */
downstreamFailures++;
close(sock);
if (downstreamFailures > ds->retries) {
throw;
}
}
} while(downstreamFailures <= ds->retries);
return -1;
}
struct ConnectionInfo
{
ConnectionInfo(): cs(nullptr), fd(-1)
{
}
ConnectionInfo(const ConnectionInfo& rhs) = delete;
ConnectionInfo& operator=(const ConnectionInfo& rhs) = delete;
ConnectionInfo& operator=(ConnectionInfo&& rhs)
{
remote = rhs.remote;
cs = rhs.cs;
rhs.cs = nullptr;
fd = rhs.fd;
rhs.fd = -1;
return *this;
}
~ConnectionInfo()
{
if (fd != -1) {
close(fd);
fd = -1;
}
}
ComboAddress remote;
ClientState* cs{nullptr};
int fd{-1};
};
uint64_t g_maxTCPQueuedConnections{1000};
size_t g_maxTCPQueriesPerConn{0};
size_t g_maxTCPConnectionDuration{0};
size_t g_maxTCPConnectionsPerClient{0};
static std::mutex tcpClientsCountMutex;
static std::map<ComboAddress,size_t,ComboAddress::addressOnlyLessThan> tcpClientsCount;
bool g_useTCPSinglePipe{false};
std::atomic<uint16_t> g_downstreamTCPCleanupInterval{60};
void* tcpClientThread(int pipefd);
static void decrementTCPClientCount(const ComboAddress& client)
{
if (g_maxTCPConnectionsPerClient) {
std::lock_guard<std::mutex> lock(tcpClientsCountMutex);
tcpClientsCount[client]--;
if (tcpClientsCount[client] == 0) {
tcpClientsCount.erase(client);
}
}
}
void TCPClientCollection::addTCPClientThread()
{
int pipefds[2] = { -1, -1};
vinfolog("Adding TCP Client thread");
if (d_useSinglePipe) {
pipefds[0] = d_singlePipe[0];
pipefds[1] = d_singlePipe[1];
}
else {
if (pipe(pipefds) < 0) {
errlog("Error creating the TCP thread communication pipe: %s", strerror(errno));
return;
}
if (!setNonBlocking(pipefds[1])) {
close(pipefds[0]);
close(pipefds[1]);
errlog("Error setting the TCP thread communication pipe non-blocking: %s", strerror(errno));
return;
}
}
{
std::lock_guard<std::mutex> lock(d_mutex);
if (d_numthreads >= d_tcpclientthreads.capacity()) {
warnlog("Adding a new TCP client thread would exceed the vector capacity (%d/%d), skipping", d_numthreads.load(), d_tcpclientthreads.capacity());
if (!d_useSinglePipe) {
close(pipefds[0]);
close(pipefds[1]);
}
return;
}
try {
thread t1(tcpClientThread, pipefds[0]);
t1.detach();
}
catch(const std::runtime_error& e) {
/* the thread creation failed, don't leak */
errlog("Error creating a TCP thread: %s", e.what());
if (!d_useSinglePipe) {
close(pipefds[0]);
close(pipefds[1]);
}
return;
}
d_tcpclientthreads.push_back(pipefds[1]);
}
++d_numthreads;
}
static bool getNonBlockingMsgLen(int fd, uint16_t* len, int timeout)
try
{
uint16_t raw;
size_t ret = readn2WithTimeout(fd, &raw, sizeof raw, timeout);
if(ret != sizeof raw)
return false;
*len = ntohs(raw);
return true;
}
catch(...) {
return false;
}
static bool getNonBlockingMsgLenFromClient(TCPIOHandler& handler, uint16_t* len)
try
{
uint16_t raw;
size_t ret = handler.read(&raw, sizeof raw, g_tcpRecvTimeout);
if(ret != sizeof raw)
return false;
*len = ntohs(raw);
return true;
}
catch(...) {
return false;
}
static bool maxConnectionDurationReached(unsigned int maxConnectionDuration, time_t start, unsigned int& remainingTime)
{
if (maxConnectionDuration) {
time_t curtime = time(nullptr);
unsigned int elapsed = 0;
if (curtime > start) { // To prevent issues when time goes backward
elapsed = curtime - start;
}
if (elapsed >= maxConnectionDuration) {
return true;
}
remainingTime = maxConnectionDuration - elapsed;
}
return false;
}
void cleanupClosedTCPConnections(std::map<ComboAddress,int>& sockets)
{
for(auto it = sockets.begin(); it != sockets.end(); ) {
if (isTCPSocketUsable(it->second)) {
++it;
}
else {
close(it->second);
it = sockets.erase(it);
}
}
}
std::shared_ptr<TCPClientCollection> g_tcpclientthreads;
void* tcpClientThread(int pipefd)
{
/* we get launched with a pipe on which we receive file descriptors from clients that we own
from that point on */
setThreadName("dnsdist/tcpClie");
bool outstanding = false;
time_t lastTCPCleanup = time(nullptr);
LocalHolders holders;
auto localRespRulactions = g_resprulactions.getLocal();
#ifdef HAVE_DNSCRYPT
/* when the answer is encrypted in place, we need to get a copy
of the original header before encryption to fill the ring buffer */
dnsheader dhCopy;
#endif
map<ComboAddress,int> sockets;
for(;;) {
ConnectionInfo* citmp, ci;
try {
readn2(pipefd, &citmp, sizeof(citmp));
}
catch(const std::runtime_error& e) {
throw std::runtime_error("Error reading from TCP acceptor pipe (" + std::to_string(pipefd) + ") in " + std::string(isNonBlocking(pipefd) ? "non-blocking" : "blocking") + " mode: " + e.what());
}
g_tcpclientthreads->decrementQueuedCount();
ci=std::move(*citmp);
delete citmp;
uint16_t qlen, rlen;
vector<uint8_t> rewrittenResponse;
shared_ptr<DownstreamState> ds;
ComboAddress dest;
dest.reset();
dest.sin4.sin_family = ci.remote.sin4.sin_family;
socklen_t len = dest.getSocklen();
size_t queriesCount = 0;
time_t connectionStartTime = time(NULL);
std::vector<char> queryBuffer;
std::vector<char> answerBuffer;
if (getsockname(ci.fd, (sockaddr*)&dest, &len)) {
dest = ci.cs->local;
}
try {
TCPIOHandler handler(ci.fd, g_tcpRecvTimeout, ci.cs->tlsFrontend ? ci.cs->tlsFrontend->getContext() : nullptr, connectionStartTime);
for(;;) {
unsigned int remainingTime = 0;
ds = nullptr;
outstanding = false;
if(!getNonBlockingMsgLenFromClient(handler, &qlen)) {
break;
}
queriesCount++;
if (qlen < sizeof(dnsheader)) {
g_stats.nonCompliantQueries++;
break;
}
ci.cs->queries++;
g_stats.queries++;
if (g_maxTCPQueriesPerConn && queriesCount > g_maxTCPQueriesPerConn) {
vinfolog("Terminating TCP connection from %s because it reached the maximum number of queries per conn (%d / %d)", ci.remote.toStringWithPort(), queriesCount, g_maxTCPQueriesPerConn);
break;
}
if (maxConnectionDurationReached(g_maxTCPConnectionDuration, connectionStartTime, remainingTime)) {
vinfolog("Terminating TCP connection from %s because it reached the maximum TCP connection duration", ci.remote.toStringWithPort());
break;
}
bool ednsAdded = false;
bool ecsAdded = false;
/* allocate a bit more memory to be able to spoof the content,
or to add ECS without allocating a new buffer */
queryBuffer.resize(qlen + 512);
char* query = &queryBuffer[0];
handler.read(query, qlen, g_tcpRecvTimeout, remainingTime);
/* we need this one to be accurate ("real") for the protobuf message */
struct timespec queryRealTime;
struct timespec now;
gettime(&now);
gettime(&queryRealTime, true);
#ifdef HAVE_DNSCRYPT
std::shared_ptr<DNSCryptQuery> dnsCryptQuery = nullptr;
if (ci.cs->dnscryptCtx) {
dnsCryptQuery = std::make_shared<DNSCryptQuery>(ci.cs->dnscryptCtx);
uint16_t decryptedQueryLen = 0;
vector<uint8_t> response;
bool decrypted = handleDNSCryptQuery(query, qlen, dnsCryptQuery, &decryptedQueryLen, true, queryRealTime.tv_sec, response);
if (!decrypted) {
if (response.size() > 0) {
handler.writeSizeAndMsg(response.data(), response.size(), g_tcpSendTimeout);
}
break;
}
qlen = decryptedQueryLen;
}
#endif
struct dnsheader* dh = reinterpret_cast<struct dnsheader*>(query);
if (!checkQueryHeaders(dh)) {
goto drop;
}
string poolname;
int delayMsec=0;
const uint16_t* flags = getFlagsFromDNSHeader(dh);
uint16_t origFlags = *flags;
uint16_t qtype, qclass;
unsigned int consumed = 0;
DNSName qname(query, qlen, sizeof(dnsheader), false, &qtype, &qclass, &consumed);
DNSQuestion dq(&qname, qtype, qclass, consumed, &dest, &ci.remote, dh, queryBuffer.size(), qlen, true, &queryRealTime);
if (!processQuery(holders, dq, poolname, &delayMsec, now)) {
goto drop;
}
if(dq.dh->qr) { // something turned it into a response
fixUpQueryTurnedResponse(dq, origFlags);
DNSResponse dr(dq.qname, dq.qtype, dq.qclass, dq.consumed, dq.local, dq.remote, reinterpret_cast<dnsheader*>(query), dq.size, dq.len, true, &queryRealTime);
#ifdef HAVE_PROTOBUF
dr.uniqueId = dq.uniqueId;
#endif
dr.qTag = dq.qTag;
if (!processResponse(holders.selfAnsweredRespRulactions, dr, &delayMsec)) {
goto drop;
}
#ifdef HAVE_DNSCRYPT
if (!encryptResponse(query, &dq.len, dq.size, true, dnsCryptQuery, nullptr, nullptr)) {
goto drop;
}
#endif
handler.writeSizeAndMsg(query, dq.len, g_tcpSendTimeout);
g_stats.selfAnswered++;
continue;
}
std::shared_ptr<ServerPool> serverPool = getPool(*holders.pools, poolname);
std::shared_ptr<DNSDistPacketCache> packetCache = serverPool->packetCache;
auto policy = *(holders.policy);
if (serverPool->policy != nullptr) {
policy = *(serverPool->policy);
}
auto servers = serverPool->getServers();
if (policy.isLua) {
std::lock_guard<std::mutex> lock(g_luamutex);
ds = policy.policy(servers, &dq);
}
else {
ds = policy.policy(servers, &dq);
}
if (dq.useECS && ((ds && ds->useECS) || (!ds && serverPool->getECS()))) {
if (!handleEDNSClientSubnet(dq, &(ednsAdded), &(ecsAdded), g_preserveTrailingData)) {
vinfolog("Dropping query from %s because we couldn't insert the ECS value", ci.remote.toStringWithPort());
goto drop;
}
}
uint32_t cacheKey = 0;
boost::optional<Netmask> subnet;
bool dnssecOK = false;
if (packetCache && !dq.skipCache) {
char cachedResponse[4096];
uint16_t cachedResponseSize = sizeof cachedResponse;
uint32_t allowExpired = ds ? 0 : g_staleCacheEntriesTTL;
dnssecOK = (getEDNSZ(dq) & EDNS_HEADER_FLAG_DO);
if (packetCache->get(dq, (uint16_t) consumed, dq.dh->id, cachedResponse, &cachedResponseSize, &cacheKey, subnet, dnssecOK, allowExpired)) {
DNSResponse dr(dq.qname, dq.qtype, dq.qclass, dq.consumed, dq.local, dq.remote, (dnsheader*) cachedResponse, sizeof cachedResponse, cachedResponseSize, true, &queryRealTime);
#ifdef HAVE_PROTOBUF
dr.uniqueId = dq.uniqueId;
#endif
dr.qTag = dq.qTag;
if (!processResponse(holders.cacheHitRespRulactions, dr, &delayMsec)) {
goto drop;
}
#ifdef HAVE_DNSCRYPT
if (!encryptResponse(cachedResponse, &cachedResponseSize, sizeof cachedResponse, true, dnsCryptQuery, nullptr, nullptr)) {
goto drop;
}
#endif
handler.writeSizeAndMsg(cachedResponse, cachedResponseSize, g_tcpSendTimeout);
g_stats.cacheHits++;
continue;
}
g_stats.cacheMisses++;
}
if(!ds) {
g_stats.noPolicy++;
if (g_servFailOnNoPolicy) {
restoreFlags(dh, origFlags);
dq.dh->rcode = RCode::ServFail;
dq.dh->qr = true;
DNSResponse dr(dq.qname, dq.qtype, dq.qclass, dq.consumed, dq.local, dq.remote, reinterpret_cast<dnsheader*>(query), dq.size, dq.len, false, &queryRealTime);
#ifdef HAVE_PROTOBUF
dr.uniqueId = dq.uniqueId;
#endif
dr.qTag = dq.qTag;
if (!processResponse(holders.selfAnsweredRespRulactions, dr, &delayMsec)) {
goto drop;
}
#ifdef HAVE_DNSCRYPT
if (!encryptResponse(query, &dq.len, dq.size, true, dnsCryptQuery, nullptr, nullptr)) {
goto drop;
}
#endif
handler.writeSizeAndMsg(query, dq.len, g_tcpSendTimeout);
// no response-only statistics counter to update.
continue;
}
break;
}
if (dq.addXPF && ds->xpfRRCode != 0) {
addXPF(dq, ds->xpfRRCode, g_preserveTrailingData);
}
int dsock = -1;
uint16_t downstreamFailures=0;
#ifdef MSG_FASTOPEN
bool freshConn = true;
#endif /* MSG_FASTOPEN */
if(sockets.count(ds->remote) == 0) {
dsock=setupTCPDownstream(ds, downstreamFailures);
sockets[ds->remote]=dsock;
}
else {
dsock=sockets[ds->remote];
#ifdef MSG_FASTOPEN
freshConn = false;
#endif /* MSG_FASTOPEN */
}
ds->queries++;
ds->outstanding++;
outstanding = true;
retry:;
if (dsock < 0) {
sockets.erase(ds->remote);
break;
}
if (ds->retries > 0 && downstreamFailures > ds->retries) {
vinfolog("Downstream connection to %s failed %d times in a row, giving up.", ds->getName(), downstreamFailures);
close(dsock);
dsock=-1;
sockets.erase(ds->remote);
break;
}
try {
int socketFlags = 0;
#ifdef MSG_FASTOPEN
if (ds->tcpFastOpen && freshConn) {
socketFlags |= MSG_FASTOPEN;
}
#endif /* MSG_FASTOPEN */
sendSizeAndMsgWithTimeout(dsock, dq.len, query, ds->tcpSendTimeout, &ds->remote, &ds->sourceAddr, ds->sourceItf, 0, socketFlags);
}
catch(const runtime_error& e) {
vinfolog("Downstream connection to %s died on us (%s), getting a new one!", ds->getName(), e.what());
close(dsock);
dsock=-1;
sockets.erase(ds->remote);
downstreamFailures++;
dsock=setupTCPDownstream(ds, downstreamFailures);
sockets[ds->remote]=dsock;
#ifdef MSG_FASTOPEN
freshConn=true;
#endif /* MSG_FASTOPEN */
goto retry;
}
bool xfrStarted = false;
bool isXFR = (dq.qtype == QType::AXFR || dq.qtype == QType::IXFR);
if (isXFR) {
dq.skipCache = true;
}
bool firstPacket=true;
getpacket:;
if(!getNonBlockingMsgLen(dsock, &rlen, ds->tcpRecvTimeout)) {
vinfolog("Downstream connection to %s died on us phase 2, getting a new one!", ds->getName());
close(dsock);
dsock=-1;
sockets.erase(ds->remote);
downstreamFailures++;
dsock=setupTCPDownstream(ds, downstreamFailures);
sockets[ds->remote]=dsock;
#ifdef MSG_FASTOPEN
freshConn=true;
#endif /* MSG_FASTOPEN */
if(xfrStarted) {
goto drop;
}
goto retry;
}
size_t responseSize = rlen;
uint16_t addRoom = 0;
#ifdef HAVE_DNSCRYPT
if (dnsCryptQuery && (UINT16_MAX - rlen) > (uint16_t) DNSCRYPT_MAX_RESPONSE_PADDING_AND_MAC_SIZE) {
addRoom = DNSCRYPT_MAX_RESPONSE_PADDING_AND_MAC_SIZE;
}
#endif
responseSize += addRoom;
answerBuffer.resize(responseSize);
char* response = answerBuffer.data();
readn2WithTimeout(dsock, response, rlen, ds->tcpRecvTimeout);
uint16_t responseLen = rlen;
if (outstanding) {
/* might be false for {A,I}XFR */
--ds->outstanding;
outstanding = false;
}
if (rlen < sizeof(dnsheader)) {
break;
}
consumed = 0;
if (firstPacket && !responseContentMatches(response, responseLen, qname, qtype, qclass, ds->remote, consumed)) {
break;
}
firstPacket=false;
if (!fixUpResponse(&response, &responseLen, &responseSize, qname, origFlags, ednsAdded, ecsAdded, rewrittenResponse, addRoom)) {
break;
}
dh = (struct dnsheader*) response;
DNSResponse dr(&qname, qtype, qclass, consumed, &dest, &ci.remote, dh, responseSize, responseLen, true, &queryRealTime);
#ifdef HAVE_PROTOBUF
dr.uniqueId = dq.uniqueId;
#endif
dr.qTag = dq.qTag;
if (!processResponse(localRespRulactions, dr, &delayMsec)) {
break;
}
if (packetCache && !dq.skipCache) {
packetCache->insert(cacheKey, subnet, origFlags, dnssecOK, qname, qtype, qclass, response, responseLen, true, dh->rcode, dq.tempFailureTTL);
}
#ifdef HAVE_DNSCRYPT
if (!encryptResponse(response, &responseLen, responseSize, true, dnsCryptQuery, &dh, &dhCopy)) {
goto drop;
}
#endif
if (!handler.writeSizeAndMsg(response, responseLen, g_tcpSendTimeout)) {
break;
}
if (isXFR) {
if (dh->rcode == 0 && dh->ancount != 0) {
if (xfrStarted == false) {
xfrStarted = true;
if (getRecordsOfTypeCount(response, responseLen, 1, QType::SOA) == 1) {
goto getpacket;
}
}
else if (getRecordsOfTypeCount(response, responseLen, 1, QType::SOA) == 0) {
goto getpacket;
}
}
/* Don't reuse the TCP connection after an {A,I}XFR */
close(dsock);
dsock=-1;
sockets.erase(ds->remote);
}
g_stats.responses++;
struct timespec answertime;
gettime(&answertime);
unsigned int udiff = 1000000.0*DiffTime(now,answertime);
g_rings.insertResponse(answertime, ci.remote, qname, dq.qtype, (unsigned int)udiff, (unsigned int)responseLen, *dh, ds->remote);
rewrittenResponse.clear();
}
}
catch(...) {}
drop:;
vinfolog("Closing TCP client connection with %s", ci.remote.toStringWithPort());
if (ds && outstanding) {
outstanding = false;
--ds->outstanding;
}
decrementTCPClientCount(ci.remote);
if (g_downstreamTCPCleanupInterval > 0 && (connectionStartTime > (lastTCPCleanup + g_downstreamTCPCleanupInterval))) {
cleanupClosedTCPConnections(sockets);
lastTCPCleanup = time(nullptr);
}
}
return 0;
}
/* spawn as many of these as required, they call Accept on a socket on which they will accept queries, and
they will hand off to worker threads & spawn more of them if required
*/
void* tcpAcceptorThread(void* p)
{
setThreadName("dnsdist/tcpAcce");
ClientState* cs = (ClientState*) p;
bool tcpClientCountIncremented = false;
ComboAddress remote;
remote.sin4.sin_family = cs->local.sin4.sin_family;
g_tcpclientthreads->addTCPClientThread();
auto acl = g_ACL.getLocal();
for(;;) {
bool queuedCounterIncremented = false;
std::unique_ptr<ConnectionInfo> ci;
tcpClientCountIncremented = false;
try {
socklen_t remlen = remote.getSocklen();
ci = std::unique_ptr<ConnectionInfo>(new ConnectionInfo);
ci->cs = cs;
#ifdef HAVE_ACCEPT4
ci->fd = accept4(cs->tcpFD, (struct sockaddr*)&remote, &remlen, SOCK_NONBLOCK);
#else
ci->fd = accept(cs->tcpFD, (struct sockaddr*)&remote, &remlen);
#endif
if(ci->fd < 0) {
throw std::runtime_error((boost::format("accepting new connection on socket: %s") % strerror(errno)).str());
}
if(!acl->match(remote)) {
g_stats.aclDrops++;
vinfolog("Dropped TCP connection from %s because of ACL", remote.toStringWithPort());
continue;
}
#ifndef HAVE_ACCEPT4
if (!setNonBlocking(ci->fd)) {
continue;
}
#endif
setTCPNoDelay(ci->fd); // disable NAGLE
if(g_maxTCPQueuedConnections > 0 && g_tcpclientthreads->getQueuedCount() >= g_maxTCPQueuedConnections) {
vinfolog("Dropping TCP connection from %s because we have too many queued already", remote.toStringWithPort());
continue;
}
if (g_maxTCPConnectionsPerClient) {
std::lock_guard<std::mutex> lock(tcpClientsCountMutex);
if (tcpClientsCount[remote] >= g_maxTCPConnectionsPerClient) {
vinfolog("Dropping TCP connection from %s because we have too many from this client already", remote.toStringWithPort());
continue;
}
tcpClientsCount[remote]++;
tcpClientCountIncremented = true;
}
vinfolog("Got TCP connection from %s", remote.toStringWithPort());
ci->remote = remote;
int pipe = g_tcpclientthreads->getThread();
if (pipe >= 0) {
queuedCounterIncremented = true;
auto tmp = ci.release();
try {
writen2WithTimeout(pipe, &tmp, sizeof(tmp), 0);
}
catch(...) {
delete tmp;
tmp = nullptr;
throw;
}
}
else {
g_tcpclientthreads->decrementQueuedCount();
queuedCounterIncremented = false;
if(tcpClientCountIncremented) {
decrementTCPClientCount(remote);
}
}
}
catch(std::exception& e) {
errlog("While reading a TCP question: %s", e.what());
if(tcpClientCountIncremented) {
decrementTCPClientCount(remote);
}
if (queuedCounterIncremented) {
g_tcpclientthreads->decrementQueuedCount();
}
}
catch(...){}
}
return 0;
}
|