#ifndef _NETCON_H_
#define _NETCON_H_
/* Copyright (C) 2002 Jean-Francois Dockes
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef BUILDING_RECOLL
#include "autoconfig.h"
#else
#include "config.h"
#endif
#include <sys/time.h>
#include <map>
#include <string>
#include <memory>
/// A set of classes to manage client-server communication over a
/// connection-oriented network, or a pipe.
///
/// The listening/connection-accepting code currently only uses
/// TCP. The classes include client-side and server-side (accepting)
/// endpoints. Netcon also has server-side static code to handle a set
/// of client connections in parallel. This should be moved to a
/// friend class.
///
/// The client data transfer class can also be used for
/// timeout-protected/asynchronous io using a given fd (ie a pipe
/// descriptor)
/// Base class for all network endpoints:
class Netcon;
typedef std::shared_ptr<Netcon> NetconP;
class SelectLoop;
class Netcon {
public:
enum Event {NETCONPOLL_READ = 0x1, NETCONPOLL_WRITE = 0x2};
Netcon()
: m_peer(0), m_fd(-1), m_ownfd(true), m_didtimo(0), m_wantedEvents(0),
m_loop(0) {
}
virtual ~Netcon();
/// Remember whom we're talking to. We let external code do this because
/// the application may have a non-dns method to find the peer name.
virtual void setpeer(const char *hostname);
/// Retrieve the peer's hostname. Only works if it was set before !
virtual const char *getpeer() {
return m_peer ? (const char *)m_peer : "none";
}
/// Set or reset the TCP_NODELAY option.
virtual int settcpnodelay(int on = 1);
/// Did the last receive() call time out ? Resets the flag.
virtual int timedout() {
int s = m_didtimo;
m_didtimo = 0;
return s;
}
/// Return string version of last syscall error
virtual char *sterror();
/// Return the socket descriptor
virtual int getfd() {
return m_fd;
}
/// Close the current connection if it is open
virtual void closeconn();
/// Set/reset the non-blocking flag on the underlying fd. Returns
/// prev state The default is that sockets are blocking except
/// when added to the selectloop, or, transparently, to handle
/// connection timeout issues.
virtual int set_nonblock(int onoff);
/// Decide what events the connection will be looking for
/// (NETCONPOLL_READ, NETCONPOLL_WRITE)
int setselevents(int evs) {
return m_wantedEvents = evs;
}
/// Retrieve the connection's currently monitored set of events
int getselevents() {
return m_wantedEvents;
}
/// Add events to current set
int addselevents(int evs) {
return m_wantedEvents |= evs;
}
/// Clear events from current set
int clearselevents(int evs) {
return m_wantedEvents &= ~evs;
}
friend class SelectLoop;
SelectLoop *getloop() {
return m_loop;
}
/// Utility function for a simplified select() interface: check one fd
/// for reading or writing, for a specified maximum number of seconds.
static int select1(int fd, int secs, int writing = 0);
protected:
char *m_peer; // Name of the connected host
int m_fd;
bool m_ownfd;
int m_didtimo;
// Used when part of the selectloop map.
short m_wantedEvents;
SelectLoop *m_loop;
// Method called by the selectloop when something can be done with a netcon
virtual int cando(Netcon::Event reason) = 0;
// Called when added to loop
virtual void setloop(SelectLoop *loop) {
m_loop = loop;
}
};
/// The selectloop interface is used to implement parallel servers.
// The select loop mechanism allows several netcons to be used for io
// in a program without blocking as long as there is data to be read
// or written. In a multithread program which is also using select, it
// would typically make sense to have one SelectLoop active per
// thread.
class SelectLoop {
public:
SelectLoop()
: m_selectloopDoReturn(false), m_selectloopReturnValue(0),
m_placetostart(0),
m_periodichandler(0), m_periodicparam(0), m_periodicmillis(0) {
}
/// Loop waiting for events on the connections and call the
/// cando() method on the object when something happens (this will in
/// turn typically call the app callback set on the netcon). Possibly
/// call the periodic handler (if set) at regular intervals.
/// @return -1 for error. 0 if no descriptors left for i/o. 1 for periodic
/// timeout (should call back in after processing)
int doLoop();
/// Call from data handler: make selectloop return the param value
void loopReturn(int value) {
m_selectloopDoReturn = true;
m_selectloopReturnValue = value;
}
/// Add a connection to be monitored (this will usually be called
/// from the server's listen connection's accept callback)
int addselcon(NetconP con, int events);
/// Remove a connection from the monitored set. This is
/// automatically called when EOF is detected on a connection.
int remselcon(NetconP con);
/// Set a function to be called periodically, or a time before return.
/// @param handler the function to be called.
/// - if it is 0, selectloop() will return after ms mS (and can be called
/// again
/// - if it is not 0, it will be called at ms mS intervals. If its return
/// value is <= 0, selectloop will return.
/// @param clp client data to be passed to handler at every call.
/// @param ms milliseconds interval between handler calls or
/// before return. Set to 0 for no periodic handler.
void setperiodichandler(int (*handler)(void *), void *clp, int ms);
private:
// Set by client callback to tell selectloop to return.
bool m_selectloopDoReturn;
int m_selectloopReturnValue;
int m_placetostart;
// Map of NetconP indexed by fd
std::map<int, NetconP> m_polldata;
// The last time we did the periodic thing. Initialized by setperiodic()
struct timeval m_lasthdlcall;
// The call back function and its parameter
int (*m_periodichandler)(void *);
void *m_periodicparam;
// The periodic interval
int m_periodicmillis;
void periodictimeout(struct timeval *tv);
int maybecallperiodic();
};
///////////////////////
class NetconData;
/// Class for the application callback routine (when in selectloop).
///
/// This is set by the app on the NetconData by calling
/// setcallback(). It is then called from the NetconData's cando()
/// routine, itself called by selectloop.
///
/// It would be nicer to override cando() in a subclass instead of
/// setting a callback, but this can't be done conveniently because
/// accept() always creates a base NetconData (another approach would
/// be to pass a factory function to the listener, to create
/// NetconData derived classes).
class NetconWorker {
public:
virtual ~NetconWorker() {}
virtual int data(NetconData *con, Netcon::Event reason) = 0;
};
/// Base class for connections that actually transfer data. T
class NetconData : public Netcon {
public:
NetconData(bool cancellable = false);
virtual ~NetconData();
/// Write data to the connection.
/// @param buf the data buffer
/// @param cnt the number of bytes we should try to send
/// @param expedited send data in as 'expedited' data.
/// @return the count of bytes actually transferred, -1 if an
/// error occurred.
virtual int send(const char *buf, int cnt, int expedited = 0);
/// Read from the connection
/// @param buf the data buffer
/// @param cnt the number of bytes we should try to read (but we return
/// as soon as we get data)
/// @param timeo maximum number of seconds we should be waiting for data.
/// @return the count of bytes actually read (0 for EOF), or
/// TimeoutOrError (-1) for timeout or error (call timedout() to
/// discriminate and reset), Cancelled (-2) if cancelled.
enum RcvReason {Eof = 0, TimeoutOrError = -1, Cancelled = -2};
virtual int receive(char *buf, int cnt, int timeo = -1);
virtual void cancelReceive();
/// Loop on receive until cnt bytes are actually read or a timeout occurs
virtual int doreceive(char *buf, int cnt, int timeo = -1);
/// Read a line of text on an ascii connection. Returns -1 or byte count
/// including final 0. \n is kept
virtual int getline(char *buf, int cnt, int timeo = -1);
/// Set handler to be called when the connection is placed in the
/// selectloop and an event occurs.
virtual void setcallback(std::shared_ptr<NetconWorker> user) {
m_user = user;
}
private:
char *m_buf; // Buffer. Only used when doing getline()s
char *m_bufbase; // Pointer to current 1st byte of useful data
int m_bufbytes; // Bytes of data.
int m_bufsize; // Total buffer size
int m_wkfds[2];
std::shared_ptr<NetconWorker> m_user;
virtual int cando(Netcon::Event reason); // Selectloop slot
};
/// Network endpoint, client side.
class NetconCli : public NetconData {
public:
NetconCli(bool cancellable = false)
: NetconData(cancellable), m_silentconnectfailure(false) {
}
/// Open connection to specified host and named service. Set host
/// to an absolute path name for an AF_UNIX service. serv is
/// ignored in this case.
int openconn(const char *host, const char *serv, int timeo = -1);
/// Open connection to specified host and numeric port. port is in
/// HOST byte order. Set host to an absolute path name for an
/// AF_UNIX service. serv is ignored in this case.
int openconn(const char *host, unsigned int port, int timeo = -1);
/// Reuse existing fd.
/// We DONT take ownership of the fd, and do no closin' EVEN on an
/// explicit closeconn() or setconn() (use getfd(), close,
/// setconn(-1) if you need to really close the fd and have no
/// other copy).
int setconn(int fd);
/// Do not log message if openconn() fails.
void setSilentFail(bool onoff) {
m_silentconnectfailure = onoff;
}
private:
bool m_silentconnectfailure; // No logging of connection failures if set
};
class NetconServCon;
#ifdef NETCON_ACCESSCONTROL
struct intarrayparam {
int len;
unsigned int *intarray;
};
#endif /* NETCON_ACCESSCONTROL */
/// Server listening end point.
///
/// if NETCON_ACCESSCONTROL is defined during compilation,
/// NetconServLis has primitive access control features: okaddrs holds
/// the host addresses for the hosts which we allow to connect to
/// us. okmasks holds the masks to be used for comparison. okmasks
/// can be shorter than okaddrs, in which case we use the last entry
/// for all addrs beyond the masks array length. Both arrays are
/// retrieved from the configuration file when we create the endpoint
/// the key is either based on the service name (ex: cdpathdb_okaddrs,
/// cdpathdb_okmasks), or "default" if the service name is not found
/// (ex: default_okaddrs, default_okmasks)
class NetconServLis : public Netcon {
public:
NetconServLis() {
#ifdef NETCON_ACCESSCONTROL
permsinit = 0;
okaddrs.len = okmasks.len = 0;
okaddrs.intarray = okmasks.intarray = 0;
#endif /* NETCON_ACCESSCONTROL */
}
~NetconServLis();
/// Open named service. Used absolute pathname to create an
/// AF_UNIX path-based socket instead of an IP one.
int openservice(const char *serv, int backlog = 10);
/// Open service by port number.
int openservice(int port, int backlog = 10);
/// Wait for incoming connection. Returned connected Netcon
NetconServCon *accept(int timeo = -1);
protected:
/// This should be overriden in a derived class to handle incoming
/// connections. It will usually call NetconServLis::accept(), and
/// insert the new connection in the selectloop.
virtual int cando(Netcon::Event reason);
// Empty if port was numeric, else service name or socket path
std::string m_serv;
private:
#ifdef NETCON_ACCESSCONTROL
int permsinit;
struct intarrayparam okaddrs;
struct intarrayparam okmasks;
int initperms(const char *servicename);
int initperms(int port);
int checkperms(void *cli, int clilen);
#endif /* NETCON_ACCESSCONTROL */
};
/// Server-side accepted client connection. The only specific code
/// allows closing the listening endpoint in the child process (in the
/// case of a forking server)
class NetconServCon : public NetconData {
public:
NetconServCon(int newfd, Netcon* lis = 0) {
m_liscon = lis;
m_fd = newfd;
}
/// This is for forked servers that want to get rid of the main socket
void closeLisCon() {
if (m_liscon) {
m_liscon->closeconn();
}
}
private:
Netcon* m_liscon;
};
#endif /* _NETCON_H_ */