summaryrefslogtreecommitdiff
path: root/include/socketengine.h
blob: 1a0a61670f7e8439a03393c919d9bee3e1074735 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2009 InspIRCd Development Team
 * See: http://wiki.inspircd.org/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#ifndef __SOCKETENGINE__
#define __SOCKETENGINE__

#include <vector>
#include <string>
#include <map>
#include "inspircd_config.h"
#include "base.h"

/** Types of event an EventHandler may receive.
 * EVENT_READ is a readable file descriptor,
 * and EVENT_WRITE is a writeable file descriptor.
 * EVENT_ERROR can always occur, and indicates
 * a write error or read error on the socket,
 * e.g. EOF condition or broken pipe.
 */
enum EventType
{
	/** Read event */
	EVENT_READ	=	0,
	/** Write event */
	EVENT_WRITE	=	1,
	/** Error event */
	EVENT_ERROR	=	2
};

/**
 * Event mask for SocketEngine events
 */
enum EventMask
{
	/** Do not test this socket for readability
	 */
	FD_WANT_NO_READ = 0x1,
	/** Give a read event at all times when reads will not block.
	 */
	FD_WANT_POLL_READ = 0x2,
	/** Give a read event when there is new data to read.
	 *
	 * An event MUST be sent if there is new data to be read, and the most
	 * recent read/recv() on this FD returned EAGAIN. An event MAY be sent
	 * at any time there is data to be read on the socket.
	 */
	FD_WANT_FAST_READ = 0x4,
	/** Give an optional read event when reads begin to unblock
	 *
	 * This state is useful if you want to leave data in the OS receive
	 * queue but not get continuous event notifications about it, because
	 * it may not require a system call to transition from FD_WANT_FAST_READ
	 */
	FD_WANT_EDGE_READ = 0x8,
	
	/** Mask for all read events */
	FD_WANT_READ_MASK = 0x0F,

	/** Do not test this socket for writeability
	 */
	FD_WANT_NO_WRITE = 0x10,
	/** Give a write event at all times when writes will not block.
	 *
	 * You probably shouldn't use this state; if it's likely that the write
	 * will not block, try it first, then use FD_WANT_FAST_WRITE if it
	 * fails. If it's likely to block (or you are using polling-style reads)
	 * then use FD_WANT_SINGLE_WRITE.
	 */
	FD_WANT_POLL_WRITE = 0x20,
	/** Give a write event when writes don't block any more
	 *
	 * An event MUST be sent if writes will not block, and the most recent
	 * write/send() on this FD returned EAGAIN, or connect() returned
	 * EINPROGRESS. An event MAY be sent at any time that writes will not
	 * block.
	 *
	 * Before calling HandleEvent, a socket engine MAY change the state of
	 * the FD back to FD_WANT_EDGE_WRITE if it is simpler (for example, if a
	 * one-shot notification was registered). If further writes are needed,
	 * it is the responsibility of the event handler to change the state to
	 * one that will generate the required notifications
	 */
	FD_WANT_FAST_WRITE = 0x40,
	/** Give an optional write event on edge-triggered write unblock.
	 *
	 * This state is useful to avoid system calls when moving to/from
	 * FD_WANT_FAST_WRITE when writing data to a mostly-unblocked socket.
	 */
	FD_WANT_EDGE_WRITE = 0x80,
	/** Request a one-shot poll-style write notification. The socket will
	 * return to the FD_WANT_NO_WRITE state before HandleEvent is called.
	 */
	FD_WANT_SINGLE_WRITE = 0x100,

	/** Mask for all write events */
	FD_WANT_WRITE_MASK = 0x1F0,

	/** Add a trial read. During the next DispatchEvents invocation, this
	 * will call HandleEvent with EVENT_READ unless reads are known to be
	 * blocking.
	 */
	FD_ADD_TRIAL_READ  = 0x1000,
	/** Assert that reads are known to block. This cancels FD_ADD_TRIAL_READ.
	 * Reset by SE before running EVENT_READ
	 */
	FD_READ_WILL_BLOCK = 0x2000,

	/** Add a trial write. During the next DispatchEvents invocation, this
	 * will call HandleEvent with EVENT_WRITE unless writes are known to be
	 * blocking.
	 * 
	 * This could be used to group several writes together into a single
	 * send() syscall, or to ensure that writes are blocking when attempting
	 * to use FD_WANT_FAST_WRITE.
	 */
	FD_ADD_TRIAL_WRITE = 0x4000,
	/** Assert that writes are known to block. This cancels FD_ADD_TRIAL_WRITE.
	 * Reset by SE before running EVENT_WRITE
	 */
	FD_WRITE_WILL_BLOCK = 0x8000, 

	/** Mask for trial read/trial write */
	FD_TRIAL_NOTE_MASK = 0x5000
};

class InspIRCd;
class Module;

/** This class is a basic I/O handler class.
 * Any object which wishes to receive basic I/O events
 * from the socketengine must derive from this class and
 * implement the HandleEvent() method. The derived class
 * must then be added to SocketEngine using the method
 * SocketEngine::AddFd(), after which point the derived
 * class will receive events to its HandleEvent() method.
 * The derived class should also implement one of Readable()
 * and Writeable(). In the current implementation, only
 * Readable() is used. If this returns true, the socketengine
 * inserts a readable socket. If it is false, the socketengine
 * inserts a writeable socket. The derived class should never
 * change the value this function returns without first
 * deleting the socket from the socket engine. The only
 * requirement beyond this for an event handler is that it
 * must have a file descriptor. What this file descriptor
 * is actually attached to is completely up to you.
 */
class CoreExport EventHandler : public Extensible
{
 private:
	/** Private state maintained by socket engine */
	int event_mask;
 protected:
	/** File descriptor.
	 * All events which can be handled must have a file descriptor.  This
	 * allows you to add events for sockets, fifo's, pipes, and various
	 * other forms of IPC.  Do not change this while the object is
	 * registered with the SocketEngine
	 */
	int fd;
 public:
	/** Get the current file descriptor
	 * @return The file descriptor of this handler
	 */
	inline int GetFd() const { return fd; }

	inline int GetEventMask() const { return event_mask; }

	/** Set a new file desciptor
	 * @param FD The new file descriptor. Do not call this method without
	 * first deleting the object from the SocketEngine if you have
	 * added it to a SocketEngine instance.
	 */
	void SetFd(int FD);

	/** Constructor
	 */
	EventHandler();

	/** Destructor
	 */
	virtual ~EventHandler() {}

	/** Process an I/O event.
	 * You MUST implement this function in your derived
	 * class, and it will be called whenever read or write
	 * events are received.
	 * @param et either one of EVENT_READ for read events,
	 * and EVENT_WRITE for write events.
	 */
	virtual void HandleEvent(EventType et, int errornum = 0) = 0;

	friend class SocketEngine;
};

/** Provides basic file-descriptor-based I/O support.
 * The actual socketengine class presents the
 * same interface on all operating systems, but
 * its private members and internal behaviour
 * should be treated as blackboxed, and vary
 * from system to system and upon the config
 * settings chosen by the server admin. The current
 * version supports select, epoll and kqueue.
 * The configure script will enable a socket engine
 * based upon what OS is detected, and will derive
 * a class from SocketEngine based upon what it finds.
 * The derived classes file will also implement a
 * classfactory, SocketEngineFactory, which will
 * create a derived instance of SocketEngine using
 * polymorphism so that the core and modules do not
 * have to be aware of which SocketEngine derived
 * class they are using.
 */
class CoreExport SocketEngine
{
 protected:
	/** Current number of descriptors in the engine
	 */
	int CurrentSetSize;
	/** Reference table, contains all current handlers
	 */
	EventHandler** ref;
	/** List of handlers that want a trial read/write
	 */
	std::set<int> trials;

	int MAX_DESCRIPTORS;

	size_t indata;
	size_t outdata;
	time_t lastempty;

	void UpdateStats(size_t len_in, size_t len_out);

	virtual void OnSetEvent(EventHandler* eh, int old_mask, int new_mask) = 0;
	void SetEventMask(EventHandler* eh, int value);
public:

	double TotalEvents;
	double ReadEvents;
	double WriteEvents;
	double ErrorEvents;

	/** Constructor.
	 * The constructor transparently initializes
	 * the socket engine which the ircd is using.
	 * Please note that if there is a catastrophic
	 * failure (for example, you try and enable
	 * epoll on a 2.4 linux kernel) then this
	 * function may bail back to the shell.
	 */
	SocketEngine();

	/** Destructor.
	 * The destructor transparently tidies up
	 * any resources used by the socket engine.
	 */
	virtual ~SocketEngine();

	/** Add an EventHandler object to the engine.  Use AddFd to add a file
	 * descriptor to the engine and have the socket engine monitor it. You
	 * must provide an object derived from EventHandler which implements
	 * HandleEvent().
	 * @param eh An event handling object to add
	 * @param event_mask The initial event mask for the object
	 */
	virtual bool AddFd(EventHandler* eh, int event_mask) = 0;

	/** If you call this function and pass it an
	 * event handler, that event handler will
	 * receive the next available write event,
	 * even if the socket is a readable socket only.
	 * Developers should avoid constantly keeping
	 * an eventhandler in the writeable state,
	 * as this will consume large amounts of
	 * CPU time.
	 * @param eh The event handler to change
	 * @param event_mask The changes to make to the wait state
	 */
	void ChangeEventMask(EventHandler* eh, int event_mask);

	/** Returns the highest file descriptor you may store in the socket engine
	 * @return The maximum fd value
	 */
	inline int GetMaxFds() const { return MAX_DESCRIPTORS; }

	/** Returns the number of file descriptors being queried
	 * @return The set size
	 */
	inline int GetUsedFds() const { return CurrentSetSize; }

	/** Delete an event handler from the engine.
	 * This function call deletes an EventHandler
	 * from the engine, returning true if it succeeded
	 * and false if it failed. This does not free the
	 * EventHandler pointer using delete, if this is
	 * required you must do this yourself.
	 * Note on forcing deletes. DO NOT DO THIS! This is
	 * extremely dangerous and will most likely render the
	 * socketengine dead. This was added only for handling
	 * very rare cases where broken 3rd party libs destroys
	 * the OS socket beyond our control. If you can't explain
	 * in minute details why forcing is absolutely necessary
	 * then you don't need it. That was a NO!
	 * @param eh The event handler object to remove
	 * @param force *DANGEROUS* See method description!
	 * @return True if the event handler was removed
	 */
	virtual bool DelFd(EventHandler* eh, bool force = false) = 0;

	/** Returns true if a file descriptor exists in
	 * the socket engine's list.
	 * @param fd The event handler to look for
	 * @return True if this fd has an event handler
	 */
	virtual bool HasFd(int fd);

	/** Returns the EventHandler attached to a specific fd.
	 * If the fd isnt in the socketengine, returns NULL.
	 * @param fd The event handler to look for
	 * @return A pointer to the event handler, or NULL
	 */
	virtual EventHandler* GetRef(int fd);

	/** Waits for events and dispatches them to handlers.  Please note that
	 * this doesn't wait long, only a couple of milliseconds. It returns the
	 * number of events which occurred during this call.  This method will
	 * dispatch events to their handlers by calling their
	 * EventHandler::HandleEvent() methods with the necessary EventType
	 * value.
	 * @return The number of events which have occured.
	 */
	virtual int DispatchEvents() = 0;

	/** Dispatch trial reads and writes. This causes the actual socket I/O
	 * to happen when writes have been pre-buffered.
	 */
	virtual void DispatchTrialWrites();

	/** Returns the socket engines name.  This returns the name of the
	 * engine for use in /VERSION responses.
	 * @return The socket engine name
	 */
	virtual std::string GetName() = 0;

	/** Returns true if the file descriptors in the given event handler are
	 * within sensible ranges which can be handled by the socket engine.
	 */
	virtual bool BoundsCheckFd(EventHandler* eh);

	/** Abstraction for BSD sockets accept(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Accept(EventHandler* fd, sockaddr *addr, socklen_t *addrlen);

	/** Abstraction for BSD sockets close(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Close(EventHandler* fd);

	/** Abstraction for BSD sockets close(2).
	 * This function should emulate its namesake system call exactly.
	 * This function should emulate its namesake system call exactly.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Close(int fd);

	/** Abstraction for BSD sockets send(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Send(EventHandler* fd, const void *buf, size_t len, int flags);

	/** Abstraction for BSD sockets recv(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Recv(EventHandler* fd, void *buf, size_t len, int flags);

	/** Abstraction for BSD sockets recvfrom(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int RecvFrom(EventHandler* fd, void *buf, size_t len, int flags, sockaddr *from, socklen_t *fromlen);

	/** Abstraction for BSD sockets sendto(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int SendTo(EventHandler* fd, const void *buf, size_t len, int flags, const sockaddr *to, socklen_t tolen);

	/** Abstraction for BSD sockets connect(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Connect(EventHandler* fd, const sockaddr *serv_addr, socklen_t addrlen);

	/** Make a file descriptor blocking.
	 * @param fd a file descriptor to set to blocking mode
	 * @return 0 on success, -1 on failure, errno is set appropriately.
	 */
	virtual int Blocking(int fd);

	/** Make a file descriptor nonblocking.
	 * @param fd A file descriptor to set to nonblocking mode
	 * @return 0 on success, -1 on failure, errno is set appropriately.
	 */
	virtual int NonBlocking(int fd);

	/** Abstraction for BSD sockets shutdown(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Shutdown(EventHandler* fd, int how);

	/** Abstraction for BSD sockets shutdown(2).
	 * This function should emulate its namesake system call exactly.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Shutdown(int fd, int how);

	/** Abstraction for BSD sockets bind(2).
	 * This function should emulate its namesake system call exactly.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Bind(int fd, const sockaddr *my_addr, socklen_t addrlen);

	/** Abstraction for BSD sockets listen(2).
	 * This function should emulate its namesake system call exactly.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int Listen(int sockfd, int backlog);

	/** Abstraction for BSD sockets getsockname(2).
	 * This function should emulate its namesake system call exactly.
	 * @param fd This version of the call takes an EventHandler instead of a bare file descriptor.
	 * @return This method should return exactly the same values as the system call it emulates.
	 */
	virtual int GetSockName(EventHandler* fd, sockaddr *name, socklen_t* namelen);

	/** This function is called immediately after fork().
	 * Some socket engines (notably kqueue) cannot have their
	 * handles inherited by forked processes. This method
	 * allows for the socket engine to re-create its handle
	 * after the daemon forks as the socket engine is created
	 * long BEFORE the daemon forks.
	 * @return void, but it is acceptable for this function to bail back to
	 * the shell or operating system on fatal error.
	 */
	virtual void RecoverFromFork();

	/** Get data transfer statistics, kilobits per second in and out and total.
	 */
	void GetStats(float &kbitpersec_in, float &kbitpersec_out, float &kbitpersec_total);
};

#endif