src/comm/AcceptLimiter.cc

   1 /*
   2  * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #include "squid.h"
  10 #include "comm/AcceptLimiter.h"
  11 #include "comm/Connection.h"
  12 #include "comm/TcpAcceptor.h"
  13 #include "fde.h"
  14 #include "globals.h"
  15
  16 Comm::AcceptLimiter Comm::AcceptLimiter::Instance_;
  17
  18 Comm::AcceptLimiter &
  19 Comm::AcceptLimiter::Instance()
  20 {
  21     return Instance_;
  22 }
  23
  24 void
  25 Comm::AcceptLimiter::defer(const Comm::TcpAcceptor::Pointer &afd)
  26 {
  27     debugs(5, 5, afd->conn << "; already queued: " << deferred_.size());
  28     deferred_.push_back(afd);
  29 }
  30
  31 void
  32 Comm::AcceptLimiter::removeDead(const Comm::TcpAcceptor::Pointer &afd)
  33 {
  34     for (auto it = deferred_.begin(); it != deferred_.end(); ++it) {
  35         if (*it == afd) {
  36             *it = nullptr; // fast. kick() will skip empty entries later.
  37             debugs(5,4, "Abandoned client TCP SYN by closing socket: " << afd->conn);
  38             return;
  39         }
  40     }
  41     debugs(5,4, "Not found " << afd->conn << " in queue, size: " << deferred_.size());
  42 }
  43
  44 void
  45 Comm::AcceptLimiter::kick()
  46 {
  47     debugs(5, 5, "size=" << deferred_.size());
  48     while (deferred_.size() > 0 && Comm::TcpAcceptor::okToAccept()) {
  49         /* NP: shift() is equivalent to pop_front(). Giving us a FIFO queue. */
  50         TcpAcceptor::Pointer temp = deferred_.front();
  51         deferred_.erase(deferred_.begin());
  52         if (temp.valid()) {
  53             debugs(5, 5, "doing one.");
  54             temp->acceptNext();
  55             break;
  56         }
  57     }
  58 }
  59