src/ipc/SharedListen.h

   1 /*
   2  * Copyright (C) 1996-2023 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 54    Interprocess Communication */
  10
  11 #ifndef SQUID_SRC_IPC_SHAREDLISTEN_H
  12 #define SQUID_SRC_IPC_SHAREDLISTEN_H
  13
  14 #include "base/AsyncCall.h"
  15 #include "base/Subscription.h"
  16 #include "ip/Address.h"
  17 #include "ipc/QuestionerId.h"
  18 #include "ipc/RequestId.h"
  19 #include "ipc/StartListening.h"
  20
  21 namespace Ipc
  22 {
  23
  24 /// "shared listen" is when concurrent processes are listening on the same fd
  25
  26 /// Comm::ConnAcceptor parameters holder
  27 /// all the details necessary to recreate a Comm::Connection and fde entry for the kid listener FD
  28 class OpenListenerParams
  29 {
  30 public:
  31     bool operator <(const OpenListenerParams &p) const; ///< useful for map<>
  32
  33     // bits to re-create the fde entry
  34     int sock_type = 0;
  35     int proto = 0;
  36     int fdNote = 0; ///< index into fd_note() comment strings
  37
  38     // bits to re-create the listener Comm::Connection descriptor
  39     Ip::Address addr; ///< will be memset and memcopied
  40     int flags = 0;
  41 };
  42
  43 class TypedMsgHdr;
  44
  45 /// a request for a listen socket with given parameters
  46 class SharedListenRequest
  47 {
  48 public:
  49     SharedListenRequest(const OpenListenerParams &, RequestId aMapId); ///< sender's constructor
  50     explicit SharedListenRequest(const TypedMsgHdr &hdrMsg); ///< from recvmsg()
  51     void pack(TypedMsgHdr &hdrMsg) const; ///< prepare for sendmsg()
  52
  53 public:
  54     int requestorId; ///< kidId of the requestor
  55
  56     OpenListenerParams params; ///< actual comm_open_sharedListen() parameters
  57
  58     RequestId mapId; ///< to map future response to the requestor's callback
  59 };
  60
  61 /// a response to SharedListenRequest
  62 class SharedListenResponse
  63 {
  64 public:
  65     SharedListenResponse(int fd, int errNo, RequestId aMapId); ///< sender's constructor
  66     explicit SharedListenResponse(const TypedMsgHdr &hdrMsg); ///< from recvmsg()
  67     void pack(TypedMsgHdr &hdrMsg) const; ///< prepare for sendmsg()
  68
  69     /// for Mine() tests
  70     QuestionerId intendedRecepient() const { return mapId.questioner(); }
  71
  72 public:
  73     int fd; ///< opened listening socket or -1
  74     int errNo; ///< errno value from comm_open_sharedListen() call
  75     RequestId mapId; ///< to map future response to the requestor's callback
  76 };
  77
  78 /// prepare and send SharedListenRequest to Coordinator
  79 void JoinSharedListen(const OpenListenerParams &, StartListeningCallback &);
  80
  81 /// process Coordinator response to SharedListenRequest
  82 void SharedListenJoined(const SharedListenResponse &response);
  83
  84 } // namespace Ipc;
  85
  86 #endif /* SQUID_SRC_IPC_SHAREDLISTEN_H */
  87