src/snmp/Forwarder.cc

   1 /*
   2  * Copyright (C) 1996-2019 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, 0, aPdu, aSession, aFd, anAddress), 2),
  27     fd(aFd)
  28 {
  29     debugs(49, 5, HERE << "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 != NULL) {
  42             comm_remove_close_handler(fd, closer);
  43             closer = NULL;
  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, HERE);
  55     Must(fd == params.fd);
  56     fd = -1;
  57     mustStop("commClosed");
  58 }
  59
  60 void
  61 Snmp::Forwarder::handleTimeout()
  62 {
  63     sendError(SNMP_ERR_RESOURCEUNAVAILABLE);
  64     Ipc::Forwarder::handleTimeout();
  65 }
  66
  67 void
  68 Snmp::Forwarder::handleException(const std::exception& e)
  69 {
  70     debugs(49, 3, HERE << e.what());
  71     if (fd >= 0)
  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, HERE);
  81     Snmp::Request& req = static_cast<Snmp::Request&>(*request);
  82     req.pdu.command = SNMP_PDU_RESPONSE;
  83     req.pdu.errstat = error;
  84     u_char buffer[SNMP_REQUEST_SIZE];
  85     int len = sizeof(buffer);
  86     snmp_build(&req.session, &req.pdu, buffer, &len);
  87     comm_udp_sendto(fd, req.address, buffer, len);
  88 }
  89
  90 void
  91 Snmp::SendResponse(unsigned int requestId, const Pdu& pdu)
  92 {
  93     debugs(49, 5, HERE);
  94     // snmpAgentResponse() can modify arg
  95     Pdu tmp = pdu;
  96     Snmp::Response response(requestId);
  97     snmp_pdu* response_pdu = NULL;
  98     try {
  99         response_pdu = snmpAgentResponse(&tmp);
 100         Must(response_pdu != NULL);
 101         response.pdu = static_cast<Pdu&>(*response_pdu);
 102         snmp_free_pdu(response_pdu);
 103     } catch (const std::exception& e) {
 104         debugs(49, DBG_CRITICAL, HERE << e.what());
 105         response.pdu.command = SNMP_PDU_RESPONSE;
 106         response.pdu.errstat = SNMP_ERR_GENERR;
 107     }
 108     Ipc::TypedMsgHdr message;
 109     response.pack(message);
 110     Ipc::SendMessage(Ipc::Port::CoordinatorAddr(), message);
 111 }
 112