Remove dead config records from NetHandler

include/iocore/net/NetHandler.h

@@ -24,6 +24,8 @@
 #pragma once
 
 #include <atomic>
+#include <cstddef>
+#include <type_traits>
 
 #include "iocore/eventsystem/Continuation.h"
 #include "iocore/eventsystem/EThread.h"
@@ -111,12 +113,9 @@ class NetHandler : public Continuation, public EThread::LoopTailHandler
 
   /// configuration settings for managing the active and keep-alive queues
   struct Config {
-    uint32_t max_connections_in                 = 0;
-    uint32_t max_requests_in                    = 0;
-    uint32_t inactive_threshold_in              = 0;
-    uint32_t transaction_no_activity_timeout_in = 0;
-    uint32_t keep_alive_no_activity_timeout_in  = 0;
-    uint32_t default_inactivity_timeout         = 0;
+    uint32_t max_connections_in         = 0;
+    uint32_t max_requests_in            = 0;
+    uint32_t default_inactivity_timeout = 0;
 
     /** Return the address of the first value in this struct.
 
@@ -130,6 +129,15 @@ class NetHandler : public Continuation, public EThread::LoopTailHandler
       return *(&max_connections_in + n);
     }
   };
+  // Config is addressed as an array of uint32_t through operator[], and
+  // config_value_affects_per_thread_value is a bitset indexed by field
+  // position, so the offset of each member is part of the interface.
+  static_assert(std::is_standard_layout_v<Config>);    // required for offsetof below to be well defined
+  static_assert(alignof(Config) == alignof(uint32_t)); // a member of wider type would break operator[]
+  static_assert(offsetof(Config, max_connections_in) == 0 * sizeof(uint32_t));
+  static_assert(offsetof(Config, max_requests_in) == 1 * sizeof(uint32_t));
+  static_assert(offsetof(Config, default_inactivity_timeout) == 2 * sizeof(uint32_t));
+
   /** Static global config, set and updated per process.
 
       This is updated asynchronously and then events are sent to the NetHandler

src/iocore/net/NetHandler.cc

@@ -128,15 +128,6 @@ NetHandler::update_nethandler_config(const char *str, RecDataT, RecData data, vo
   } else if (name == "proxy.config.net.max_requests_in"sv) {
     updated_member = &NetHandler::global_config.max_requests_in;
     Dbg(dbg_ctl_net_queue, "proxy.config.net.max_requests_in updated to %" PRId64, data.rec_int);
-  } else if (name == "proxy.config.net.inactive_threshold_in"sv) {
-    updated_member = &NetHandler::global_config.inactive_threshold_in;
-    Dbg(dbg_ctl_net_queue, "proxy.config.net.inactive_threshold_in updated to %" PRId64, data.rec_int);
-  } else if (name == "proxy.config.net.transaction_no_activity_timeout_in"sv) {
-    updated_member = &NetHandler::global_config.transaction_no_activity_timeout_in;
-    Dbg(dbg_ctl_net_queue, "proxy.config.net.transaction_no_activity_timeout_in updated to %" PRId64, data.rec_int);
-  } else if (name == "proxy.config.net.keep_alive_no_activity_timeout_in"sv) {
-    updated_member = &NetHandler::global_config.keep_alive_no_activity_timeout_in;
-    Dbg(dbg_ctl_net_queue, "proxy.config.net.keep_alive_no_activity_timeout_in updated to %" PRId64, data.rec_int);
   } else if (name == "proxy.config.net.default_inactivity_timeout"sv) {
     updated_member = &NetHandler::global_config.default_inactivity_timeout;
     Dbg(dbg_ctl_net_queue, "proxy.config.net.default_inactivity_timeout updated to %" PRId64, data.rec_int);
@@ -175,13 +166,8 @@ void
 NetHandler::init_for_process()
 {
   // read configuration values and setup callbacks for when they change
-  global_config.max_connections_in    = RecGetRecordInt("proxy.config.net.max_connections_in").value_or(0);
-  global_config.max_requests_in       = RecGetRecordInt("proxy.config.net.max_requests_in").value_or(0);
-  global_config.inactive_threshold_in = RecGetRecordInt("proxy.config.net.inactive_threshold_in").value_or(0);
-  global_config.transaction_no_activity_timeout_in =
-    RecGetRecordInt("proxy.config.net.transaction_no_activity_timeout_in").value_or(0);
-  global_config.keep_alive_no_activity_timeout_in =
-    RecGetRecordInt("proxy.config.net.keep_alive_no_activity_timeout_in").value_or(0);
+  global_config.max_connections_in         = RecGetRecordInt("proxy.config.net.max_connections_in").value_or(0);
+  global_config.max_requests_in            = RecGetRecordInt("proxy.config.net.max_requests_in").value_or(0);
   global_config.default_inactivity_timeout = RecGetRecordInt("proxy.config.net.default_inactivity_timeout").value_or(0);
 
   // Atomic configurations.
@@ -198,20 +184,12 @@ NetHandler::init_for_process()
 
   RecRegisterConfigUpdateCb("proxy.config.net.max_connections_in", update_nethandler_config, nullptr);
   RecRegisterConfigUpdateCb("proxy.config.net.max_requests_in", update_nethandler_config, nullptr);
-  RecRegisterConfigUpdateCb("proxy.config.net.inactive_threshold_in", update_nethandler_config, nullptr);
-  RecRegisterConfigUpdateCb("proxy.config.net.transaction_no_activity_timeout_in", update_nethandler_config, nullptr);
-  RecRegisterConfigUpdateCb("proxy.config.net.keep_alive_no_activity_timeout_in", update_nethandler_config, nullptr);
   RecRegisterConfigUpdateCb("proxy.config.net.default_inactivity_timeout", update_nethandler_config, nullptr);
   RecRegisterConfigUpdateCb("proxy.config.net.additional_accepts", update_nethandler_config, nullptr);
   RecRegisterConfigUpdateCb("proxy.config.net.per_client.max_connections_in", update_nethandler_config, nullptr);
 
   Dbg(dbg_ctl_net_queue, "proxy.config.net.max_connections_in updated to %d", global_config.max_connections_in);
   Dbg(dbg_ctl_net_queue, "proxy.config.net.max_requests_in updated to %d", global_config.max_requests_in);
-  Dbg(dbg_ctl_net_queue, "proxy.config.net.inactive_threshold_in updated to %d", global_config.inactive_threshold_in);
-  Dbg(dbg_ctl_net_queue, "proxy.config.net.transaction_no_activity_timeout_in updated to %d",
-      global_config.transaction_no_activity_timeout_in);
-  Dbg(dbg_ctl_net_queue, "proxy.config.net.keep_alive_no_activity_timeout_in updated to %d",
-      global_config.keep_alive_no_activity_timeout_in);
   Dbg(dbg_ctl_net_queue, "proxy.config.net.default_inactivity_timeout updated to %d", global_config.default_inactivity_timeout);
   Dbg(dbg_ctl_net_queue, "proxy.config.net.additional_accepts updated to %d", additional_accepts.load(std::memory_order_relaxed));
   Dbg(dbg_ctl_net_queue, "proxy.config.net.per_client.max_connections_in updated to %d",

src/iocore/net/UnixNet.cc

@@ -32,16 +32,29 @@
 #include "iocore/io_uring/IO_URING.h"
 #endif
 
+#include <limits>
+
 ink_hrtime        last_throttle_warning;
 ink_hrtime        last_shedding_warning;
 int               net_connections_throttle;
 std::atomic<bool> net_memory_throttle = false;
 int               fds_throttle;
 ink_hrtime        last_transient_accept_error;
 
+namespace
+{
+/// Config members that @c NetHandler::configure_per_thread_values reads.
+constexpr unsigned long long PER_THREAD_DEPENDENT_CONFIG{0x3};
+// std::bitset silently discards bits at or above its width, which would drop a
+// member from the set without any diagnostic if Config ever shrinks. The first
+// assertion keeps the shift in the second one well defined.
+static_assert(NetHandler::CONFIG_ITEM_COUNT < std::numeric_limits<unsigned long long>::digits);
+static_assert(PER_THREAD_DEPENDENT_CONFIG < (1ULL << NetHandler::CONFIG_ITEM_COUNT));
+} // end anonymous namespace
+
 NetHandler::Config                                     NetHandler::global_config;
 std::bitset<std::numeric_limits<unsigned int>::digits> NetHandler::active_thread_types;
-const std::bitset<NetHandler::CONFIG_ITEM_COUNT>       NetHandler::config_value_affects_per_thread_value{0x3};
+const std::bitset<NetHandler::CONFIG_ITEM_COUNT> NetHandler::config_value_affects_per_thread_value{PER_THREAD_DEPENDENT_CONFIG};
 
 namespace
 {