src/comm/Tcp.cc

   1 /*
   2  * Copyright (C) 1996-2021 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 /* DEBUG: section 05    TCP Socket Functions */
  10
  11 #include "squid.h"
  12 #include "comm/Tcp.h"
  13 #include "Debug.h"
  14
  15 #if HAVE_NETINET_TCP_H
  16 #include <netinet/tcp.h>
  17 #endif
  18 #include <type_traits>
  19
  20 /// setsockopt(2) wrapper
  21 template <typename Option>
  22 static bool
  23 SetSocketOption(const int fd, const int level, const int optName, const Option &optValue)
  24 {
  25 #if HAVE_STD_IS_TRIVIALLY_COPYABLE
  26     static_assert(std::is_trivially_copyable<Option>::value, "setsockopt() expects POD-like options");
  27 #endif
  28     static_assert(!std::is_same<Option, bool>::value, "setsockopt() uses int to represent boolean options");
  29     if (setsockopt(fd, level, optName, &optValue, sizeof(optValue)) < 0) {
  30         const auto xerrno = errno;
  31         debugs(5, DBG_IMPORTANT, "ERROR: setsockopt(2) failure: " << xstrerr(xerrno));
  32         // TODO: Generalize to throw on errors when some callers need that.
  33         return false;
  34     }
  35     return true;
  36 }
  37
  38 /// setsockopt(2) wrapper for setting typical on/off options
  39 static bool
  40 SetBooleanSocketOption(const int fd, const int level, const int optName, const bool enable)
  41 {
  42     const int optValue = enable ? 1 : 0;
  43     return SetSocketOption(fd, level, optName, optValue);
  44 }
  45
  46 void
  47 Comm::ApplyTcpKeepAlive(int fd, const TcpKeepAlive &cfg)
  48 {
  49     if (!cfg.enabled)
  50         return;
  51
  52 #if defined(TCP_KEEPCNT)
  53     if (cfg.timeout && cfg.interval) {
  54         const int count = (cfg.timeout + cfg.interval - 1) / cfg.interval; // XXX: unsigned-to-signed conversion
  55         (void)SetSocketOption(fd, IPPROTO_TCP, TCP_KEEPCNT, count);
  56     }
  57 #endif
  58 #if defined(TCP_KEEPIDLE)
  59     if (cfg.idle) {
  60         // XXX: TCP_KEEPIDLE expects an int; cfg.idle is unsigned
  61         (void)SetSocketOption(fd, IPPROTO_TCP, TCP_KEEPIDLE, cfg.idle);
  62     }
  63 #endif
  64 #if defined(TCP_KEEPINTVL)
  65     if (cfg.interval) {
  66         // XXX: TCP_KEEPINTVL expects an int; cfg.interval is unsigned
  67         (void)SetSocketOption(fd, IPPROTO_TCP, TCP_KEEPINTVL, cfg.interval);
  68     }
  69 #endif
  70     (void)SetBooleanSocketOption(fd, SOL_SOCKET, SO_KEEPALIVE, true);
  71 }