src/snmp/Forwarder.cc

   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 49    SNMP Interface */
  10
  11 #include "squid.h"
  12 #include "base/TextException.h"
  13 #include "comm.h"
  14 #include "CommCalls.h"
  15 #include "globals.h"
  16 #include "ipc/Port.h"
  17 #include "snmp/Forwarder.h"
  18 #include "snmp/Request.h"
  19 #include "snmp/Response.h"
  20 #include "snmp_core.h"
  21
  22 CBDATA_NAMESPACED_CLASS_INIT(Snmp, Forwarder);
  23
  24 Snmp::Forwarder::Forwarder(const Pdu& aPdu, const Session& aSession, int aFd,
  25                            const Ip::Address& anAddress):
  26     Ipc::Forwarder(new Request(KidIdentifier, Ipc::RequestId(), aPdu, aSession, aFd, anAddress), 2),
  27     fd(aFd)
  28 {
  29     debugs(49, 5, "FD " << aFd);
  30     Must(fd >= 0);
  31     closer = asyncCall(49, 5, "Snmp::Forwarder::noteCommClosed",
  32                        CommCbMemFunT<Forwarder, CommCloseCbParams>(this, &Forwarder::noteCommClosed));
  33     comm_add_close_handler(fd, closer);
  34 }
  35
  36 /// removes our cleanup handler of the client connection socket
  37 void
  38 Snmp::Forwarder::swanSong()
  39 {
  40     if (fd >= 0) {
  41         if (closer != nullptr) {
  42             comm_remove_close_handler(fd, closer);
  43             closer = nullptr;
  44         }
  45         fd = -1;
  46     }
  47     Ipc::Forwarder::swanSong();
  48 }
  49
  50 /// called when the client socket gets closed by some external force
  51 void
  52 Snmp::Forwarder::noteCommClosed(const CommCloseCbParams& params)
  53 {
  54     debugs(49, 5, MYNAME);
  55     Must(fd == params.fd);
  56     closer = nullptr;
  57     fd = -1;
  58     mustStop("commClosed");
  59 }
  60
  61 void
  62 Snmp::Forwarder::handleTimeout()
  63 {
  64     sendError(SNMP_ERR_RESOURCEUNAVAILABLE);
  65     Ipc::Forwarder::handleTimeout();
  66 }
  67
  68 void
  69 Snmp::Forwarder::handleException(const std::exception& e)
  70 {
  71     debugs(49, 3, e.what());
  72     sendError(SNMP_ERR_GENERR);
  73     Ipc::Forwarder::handleException(e);
  74 }
  75
  76 /// send error SNMP response
  77 void
  78 Snmp::Forwarder::sendError(int error)
  79 {
  80     debugs(49, 3, MYNAME);
  81
  82     if (fd < 0)
  83         return; // client gone
  84
  85     Snmp::Request& req = static_cast<Snmp::Request&>(*request);
  86     req.pdu.command = SNMP_PDU_RESPONSE;
  87     req.pdu.errstat = error;
  88     u_char buffer[SNMP_REQUEST_SIZE];
  89     int len = sizeof(buffer);
  90     snmp_build(&req.session, &req.pdu, buffer, &len);
  91     comm_udp_sendto(fd, req.address, buffer, len);
  92 }
  93
  94 void
  95 Snmp::SendResponse(const Ipc::RequestId requestId, const Pdu &pdu)
  96 {
  97     debugs(49, 5, MYNAME);
  98     // snmpAgentResponse() can modify arg
  99     Pdu tmp = pdu;
 100     Snmp::Response response(requestId);
 101     snmp_pdu* response_pdu = nullptr;
 102     try {
 103         response_pdu = snmpAgentResponse(&tmp);
 104         Must(response_pdu != nullptr);
 105         response.pdu = static_cast<Pdu&>(*response_pdu);
 106         snmp_free_pdu(response_pdu);
 107     } catch (const std::exception& e) {
 108         debugs(49, DBG_CRITICAL, e.what());
 109         response.pdu.command = SNMP_PDU_RESPONSE;
 110         response.pdu.errstat = SNMP_ERR_GENERR;
 111     }
 112     Ipc::TypedMsgHdr message;
 113     response.pack(message);
 114     Ipc::SendMessage(Ipc::Port::CoordinatorAddr(), message);
 115 }
 116