src/comm/AcceptLimiter.cc

   1 #include "squid.h"
   2 #include "comm/AcceptLimiter.h"
   3 #include "comm/Connection.h"
   4 #include "comm/TcpAcceptor.h"
   5 #include "fde.h"
   6 #include "globals.h"
   7
   8 Comm::AcceptLimiter Comm::AcceptLimiter::Instance_;
   9
  10 Comm::AcceptLimiter &
  11 Comm::AcceptLimiter::Instance()
  12 {
  13     return Instance_;
  14 }
  15
  16 void
  17 Comm::AcceptLimiter::defer(const Comm::TcpAcceptor::Pointer &afd)
  18 {
  19     ++ (afd->isLimited);
  20     debugs(5, 5, afd->conn << " x" << afd->isLimited);
  21     deferred_.push_back(afd);
  22 }
  23
  24 void
  25 Comm::AcceptLimiter::removeDead(const Comm::TcpAcceptor::Pointer &afd)
  26 {
  27     uint64_t abandonedClients = 0;
  28     for (unsigned int i = 0; i < deferred_.size() && afd->isLimited > 0; ++i) {
  29         if (deferred_[i] == afd) {
  30             -- deferred_[i]->isLimited;
  31             deferred_[i] = NULL; // fast. kick() will skip empty entries later.
  32             debugs(5, 5, afd->conn << " x" << afd->isLimited);
  33             ++abandonedClients;
  34         }
  35     }
  36     debugs(5,4, "Abandoned " << abandonedClients << " client TCP SYN by closing socket: " << afd->conn);
  37 }
  38
  39 void
  40 Comm::AcceptLimiter::kick()
  41 {
  42     // TODO: this could be optimized further with an iterator to search
  43     //       looking for first non-NULL, followed by dumping the first N
  44     //       with only one shift()/pop_front operation
  45     //  OR, by reimplementing as a list instead of Vector.
  46
  47     debugs(5, 5, "size=" << deferred_.size());
  48     while (deferred_.size() > 0 && fdNFree() >= RESERVED_FD) {
  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->isLimited;
  55             temp->acceptNext();
  56             break;
  57         }
  58     }
  59 }