351 lines
12 KiB
C++
351 lines
12 KiB
C++
#ifndef _NETCON_H_
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#define _NETCON_H_
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/* Copyright (C) 2002 Jean-Francois Dockes
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the
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* Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifdef BUILDING_RECOLL
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#include "autoconfig.h"
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#else
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#include "config.h"
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#endif
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#include <sys/time.h>
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#include <string>
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#include <memory>
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/// A set of classes to manage client-server communication over a
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/// connection-oriented network, or a pipe.
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///
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/// The listening/connection-accepting code currently only uses
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/// TCP. The classes include client-side and server-side (accepting)
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/// endpoints. Netcon also has server-side static code to handle a set
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/// of client connections in parallel. This should be moved to a
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/// friend class.
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///
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/// The client data transfer class can also be used for
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/// timeout-protected/asynchronous io using a given fd (ie a pipe
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/// descriptor)
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/// Base class for all network endpoints:
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class Netcon;
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typedef std::shared_ptr<Netcon> NetconP;
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class SelectLoop;
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class Netcon {
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public:
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enum Event {NETCONPOLL_READ = 0x1, NETCONPOLL_WRITE = 0x2};
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Netcon()
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: m_peer(0), m_fd(-1), m_ownfd(true), m_didtimo(0), m_wantedEvents(0),
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m_loop(0) {
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}
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virtual ~Netcon();
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/// Remember whom we're talking to. We let external code do this because
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/// the application may have a non-dns method to find the peer name.
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virtual void setpeer(const char *hostname);
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/// Retrieve the peer's hostname. Only works if it was set before !
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virtual const char *getpeer() {
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return m_peer ? (const char *)m_peer : "none";
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}
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/// Set or reset the TCP_NODELAY option.
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virtual int settcpnodelay(int on = 1);
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/// Did the last receive() call time out ? Resets the flag.
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virtual int timedout() {
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int s = m_didtimo;
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m_didtimo = 0;
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return s;
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}
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/// Return string version of last syscall error
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virtual char *sterror();
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/// Return the socket descriptor
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virtual int getfd() {
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return m_fd;
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}
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/// Close the current connection if it is open
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virtual void closeconn();
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/// Set/reset the non-blocking flag on the underlying fd. Returns
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/// prev state The default is that sockets are blocking except
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/// when added to the selectloop, or, transparently, to handle
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/// connection timeout issues.
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virtual int set_nonblock(int onoff);
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/// Decide what events the connection will be looking for
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/// (NETCONPOLL_READ, NETCONPOLL_WRITE)
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int setselevents(int evs);
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/// Retrieve the connection's currently monitored set of events
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int getselevents() {
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return m_wantedEvents;
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}
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friend class SelectLoop;
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SelectLoop *getloop() {
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return m_loop;
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}
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/// Utility function for a simplified select() interface: check one fd
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/// for reading or writing, for a specified maximum number of seconds.
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static int select1(int fd, int secs, int writing = 0);
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protected:
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char *m_peer; // Name of the connected host
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int m_fd;
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bool m_ownfd;
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int m_didtimo;
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// Used when part of the selectloop.
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short m_wantedEvents;
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SelectLoop *m_loop;
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// Method called by the selectloop when something can be done with a netcon
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virtual int cando(Netcon::Event reason) = 0;
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// Called when added to loop
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virtual void setloop(SelectLoop *loop) {
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m_loop = loop;
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}
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};
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/// The selectloop interface is used to implement parallel servers.
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// The select loop mechanism allows several netcons to be used for io
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// in a program without blocking as long as there is data to be read
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// or written. In a multithread program, if each thread needs
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// non-blocking IO it may make sense to have one SelectLoop active per
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// thread.
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class SelectLoop {
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public:
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SelectLoop();
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SelectLoop(const SelectLoop&) = delete;
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SelectLoop& operator=(const SelectLoop&) = delete;
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~SelectLoop();
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/// Add a connection to be monitored (this will usually be called
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/// from the server's listen connection's accept callback)
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int addselcon(NetconP con, int events);
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/// Remove a connection from the monitored set. This is
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/// automatically called when EOF is detected on a connection.
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int remselcon(NetconP con);
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/// Set a function to be called periodically, or a time before return.
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/// @param handler the function to be called.
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/// - if it is 0, doLoop() will return after ms mS (and can be called
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/// again)
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/// - if it is not 0, it will be called at ms mS intervals. If its return
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/// value is <= 0, selectloop will return.
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/// @param clp client data to be passed to handler at every call.
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/// @param ms milliseconds interval between handler calls or
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/// before return. Set to 0 for no periodic handler.
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void setperiodichandler(int (*handler)(void *), void *clp, int ms);
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/// Loop waiting for events on the connections and call the
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/// cando() method on the object when something happens (this will in
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/// turn typically call the app callback set on the netcon). Possibly
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/// call the periodic handler (if set) at regular intervals.
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/// @return -1 for error. 0 if no descriptors left for i/o. 1 for periodic
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/// timeout (should call back in after processing)
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int doLoop();
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/// Call from data handler: make doLoop() return @param value
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void loopReturn(int value);
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friend class Netcon;
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private:
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class Internal;
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Internal *m;
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};
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///////////////////////
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class NetconData;
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/// Class for the application callback routine (when in selectloop).
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///
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/// This is set by the app on the NetconData by calling
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/// setcallback(). It is then called from the NetconData's cando()
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/// routine, itself called by selectloop.
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///
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/// It would be nicer to override cando() in a subclass instead of
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/// setting a callback, but this can't be done conveniently because
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/// accept() always creates a base NetconData (another approach would
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/// be to pass a factory function to the listener, to create
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/// NetconData derived classes).
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class NetconWorker {
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public:
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virtual ~NetconWorker() {}
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virtual int data(NetconData *con, Netcon::Event reason) = 0;
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};
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/// Base class for connections that actually transfer data. T
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class NetconData : public Netcon {
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public:
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NetconData(bool cancellable = false);
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virtual ~NetconData();
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/// Write data to the connection.
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/// @param buf the data buffer
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/// @param cnt the number of bytes we should try to send
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/// @param expedited send data in as 'expedited' data.
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/// @return the count of bytes actually transferred, -1 if an
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/// error occurred.
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virtual int send(const char *buf, int cnt, int expedited = 0);
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/// Read from the connection
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/// @param buf the data buffer
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/// @param cnt the number of bytes we should try to read (but we return
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/// as soon as we get data)
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/// @param timeo maximum number of seconds we should be waiting for data.
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/// @return the count of bytes actually read (0 for EOF), or
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/// TimeoutOrError (-1) for timeout or error (call timedout() to
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/// discriminate and reset), Cancelled (-2) if cancelled.
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enum RcvReason {Eof = 0, TimeoutOrError = -1, Cancelled = -2};
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virtual int receive(char *buf, int cnt, int timeo = -1);
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virtual void cancelReceive();
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/// Loop on receive until cnt bytes are actually read or a timeout occurs
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virtual int doreceive(char *buf, int cnt, int timeo = -1);
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/// Read a line of text on an ascii connection. Returns -1 or byte count
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/// including final 0. \n is kept
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virtual int getline(char *buf, int cnt, int timeo = -1);
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/// Set handler to be called when the connection is placed in the
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/// selectloop and an event occurs.
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virtual void setcallback(std::shared_ptr<NetconWorker> user) {
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m_user = user;
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}
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private:
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char *m_buf; // Buffer. Only used when doing getline()s
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char *m_bufbase; // Pointer to current 1st byte of useful data
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int m_bufbytes; // Bytes of data.
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int m_bufsize; // Total buffer size
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int m_wkfds[2];
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std::shared_ptr<NetconWorker> m_user;
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virtual int cando(Netcon::Event reason); // Selectloop slot
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};
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/// Network endpoint, client side.
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class NetconCli : public NetconData {
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public:
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NetconCli(bool cancellable = false)
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: NetconData(cancellable), m_silentconnectfailure(false) {
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}
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/// Open connection to specified host and named service. Set host
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/// to an absolute path name for an AF_UNIX service. serv is
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/// ignored in this case.
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int openconn(const char *host, const char *serv, int timeo = -1);
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/// Open connection to specified host and numeric port. port is in
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/// HOST byte order. Set host to an absolute path name for an
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/// AF_UNIX service. serv is ignored in this case.
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int openconn(const char *host, unsigned int port, int timeo = -1);
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/// Reuse existing fd.
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/// We DONT take ownership of the fd, and do no closin' EVEN on an
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/// explicit closeconn() or setconn() (use getfd(), close,
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/// setconn(-1) if you need to really close the fd and have no
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/// other copy).
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int setconn(int fd);
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/// Do not log message if openconn() fails.
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void setSilentFail(bool onoff) {
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m_silentconnectfailure = onoff;
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}
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private:
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bool m_silentconnectfailure; // No logging of connection failures if set
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};
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class NetconServCon;
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#ifdef NETCON_ACCESSCONTROL
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struct intarrayparam {
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int len;
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unsigned int *intarray;
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};
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#endif /* NETCON_ACCESSCONTROL */
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/// Server listening end point.
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///
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/// if NETCON_ACCESSCONTROL is defined during compilation,
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/// NetconServLis has primitive access control features: okaddrs holds
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/// the host addresses for the hosts which we allow to connect to
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/// us. okmasks holds the masks to be used for comparison. okmasks
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/// can be shorter than okaddrs, in which case we use the last entry
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/// for all addrs beyond the masks array length. Both arrays are
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/// retrieved from the configuration file when we create the endpoint
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/// the key is either based on the service name (ex: cdpathdb_okaddrs,
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/// cdpathdb_okmasks), or "default" if the service name is not found
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/// (ex: default_okaddrs, default_okmasks)
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class NetconServLis : public Netcon {
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public:
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NetconServLis() {
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#ifdef NETCON_ACCESSCONTROL
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permsinit = 0;
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okaddrs.len = okmasks.len = 0;
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okaddrs.intarray = okmasks.intarray = 0;
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#endif /* NETCON_ACCESSCONTROL */
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}
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~NetconServLis();
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/// Open named service. Used absolute pathname to create an
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/// AF_UNIX path-based socket instead of an IP one.
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int openservice(const char *serv, int backlog = 10);
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/// Open service by port number.
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int openservice(int port, int backlog = 10);
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/// Wait for incoming connection. Returned connected Netcon
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NetconServCon *accept(int timeo = -1);
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protected:
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/// This should be overriden in a derived class to handle incoming
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/// connections. It will usually call NetconServLis::accept(), and
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/// insert the new connection in the selectloop.
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virtual int cando(Netcon::Event reason);
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// Empty if port was numeric, else service name or socket path
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std::string m_serv;
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private:
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#ifdef NETCON_ACCESSCONTROL
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int permsinit;
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struct intarrayparam okaddrs;
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struct intarrayparam okmasks;
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int initperms(const char *servicename);
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int initperms(int port);
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int checkperms(void *cli, int clilen);
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#endif /* NETCON_ACCESSCONTROL */
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};
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/// Server-side accepted client connection. The only specific code
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/// allows closing the listening endpoint in the child process (in the
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/// case of a forking server)
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class NetconServCon : public NetconData {
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public:
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NetconServCon(int newfd, Netcon* lis = 0) {
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m_liscon = lis;
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m_fd = newfd;
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}
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/// This is for forked servers that want to get rid of the main socket
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void closeLisCon() {
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if (m_liscon) {
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m_liscon->closeconn();
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}
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}
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private:
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Netcon* m_liscon;
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};
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#endif /* _NETCON_H_ */
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