trunk/src/packet.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2014 ircd-hybrid development team
 *
 *  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file packet.c
 * \brief Packet handlers.
 * \version $Id$
 */

#include "stdinc.h"
#include "list.h"
#include "s_bsd.h"
#include "conf.h"
#include "server.h"
#include "client.h"
#include "ircd.h"
#include "parse.h"
#include "fdlist.h"
#include "packet.h"
#include "irc_string.h"
#include "memory.h"
#include "send.h"
#include "misc.h"

#define READBUF_SIZE 16384

static char readBuf[READBUF_SIZE];


/*
 * client_dopacket - copy packet to client buf and parse it
 *      client_p - pointer to client structure for which the buffer data
 *             applies.
 *      buffer - pointr to the buffer containing the newly read data
 *      length - number of valid bytes of data in the buffer
 *
 * Note:
 *      It is implicitly assumed that client_dopacket() is called only
 *      with client_p of "local" variation, which contains all the
 *      necessary fields (buffer etc..)
 */
static void
client_dopacket(struct Client *client_p, char *buffer, size_t length)
{
  /* Update messages received */
  ++me.connection->recv.messages;
  ++client_p->connection->recv.messages;

  /* Update bytes received */
  client_p->connection->recv.bytes += length;
  me.connection->recv.bytes += length;

  parse(client_p, buffer, buffer + length);
}

/* extract_one_line()
 *
 * inputs       - pointer to a dbuf queue
 *              - pointer to buffer to copy data to
 * output       - length of <buffer>
 * side effects - one line is copied and removed from the dbuf
 */
static int
extract_one_line(struct dbuf_queue *qptr, char *buffer)
{
  int line_bytes = 0, empty_bytes = 0, phase = 0;
  unsigned int idx = 0;
  dlink_node *node = NULL;

  /*
   * Phase 0: "empty" characters before the line
   * Phase 1: copying the line
   * Phase 2: "empty" characters after the line
   *          (delete them as well and free some space in the dbuf)
   *
   * Empty characters are CR, LF and space (but, of course, not
   * in the middle of a line). We try to remove as much of them as we can,
   * since they simply eat server memory.
   *
   * --adx
   */
  DLINK_FOREACH(node, qptr->blocks.head)
  {
    struct dbuf_block *block = node->data;

    if (node == qptr->blocks.head)
      idx = qptr->pos;
    else
      idx = 0;

    for (; idx < block->size; ++idx)
    {
      char c = block->data[idx];

      if (IsEol(c) || (c == ' ' && phase != 1))
      {
        ++empty_bytes;

        if (phase == 1)
          phase = 2;
      }
      else switch (phase)
      {
        case 0: phase = 1;
        case 1: if (line_bytes++ < IRCD_BUFSIZE - 2)
                  *buffer++ = c;
                break;
        case 2: *buffer = '\0';
                dbuf_delete(qptr, line_bytes + empty_bytes);
                return IRCD_MIN(line_bytes, IRCD_BUFSIZE - 2);
      }
    }
  }

  /*
   * Now, if we haven't reached phase 2, ignore all line bytes
   * that we have read, since this is a partial line case.
   */
  if (phase != 2)
    line_bytes = 0;
  else
    *buffer = '\0';

  /* Remove what is now unnecessary */
  dbuf_delete(qptr, line_bytes + empty_bytes);
  return IRCD_MIN(line_bytes, IRCD_BUFSIZE - 2);
}
/*
 * parse_client_queued - parse client queued messages
 */
static void
parse_client_queued(struct Client *client_p)
{
  int dolen = 0;

  if (IsUnknown(client_p))
  {
    unsigned int i = 0;

    while (1)
    {
      if (IsDefunct(client_p))
        return;

      /* Rate unknown clients at MAX_FLOOD per loop */
      if (i >= MAX_FLOOD)
        break;

      dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);

      if (dolen == 0)
        break;

      client_dopacket(client_p, readBuf, dolen);
      ++i;

      /*
       * If they've dropped out of the unknown state, break and move
       * to the parsing for their appropriate status.  --fl
       */
      if (!IsUnknown(client_p))
        break;
    }
  }

  if (IsServer(client_p) || IsConnecting(client_p) || IsHandshake(client_p))
  {
    while (1)
    {
      if (IsDefunct(client_p))
        return;

      if ((dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf)) == 0)
        break;

      client_dopacket(client_p, readBuf, dolen);
    }
  }
  else if (IsClient(client_p))
  {
    unsigned int checkflood = 1;

    if (ConfigGeneral.no_oper_flood && HasUMode(client_p, UMODE_OPER))
      checkflood = 0;
    else if (IsCanFlood(client_p))
      checkflood = 0;

    /*
     * Handle flood protection here - if we exceed our flood limit on
     * messages in this loop, we simply drop out of the loop prematurely.
     *   -- adrian
     */
    while (1)
    {
      if (IsDefunct(client_p))
        break;

      /*
       * This flood protection works as follows:
       *
       * A client is given allow_read lines to send to the server.  Every
       * time a line is parsed, sent_parsed is increased.  sent_parsed
       * is decreased by 1 every time flood_recalc is called.
       *
       * Thus a client can 'burst' allow_read lines to the server, any
       * excess lines will be parsed one per flood_recalc() call.
       *
       * Therefore a client will be penalised more if they keep flooding,
       * as sent_parsed will always hover around the allow_read limit
       * and no 'bursts' will be permitted.
       */
      if (checkflood)
        if (client_p->connection->sent_parsed >= client_p->connection->allow_read)
          break;

      dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);

      if (dolen == 0)
        break;

      client_dopacket(client_p, readBuf, dolen);
      ++client_p->connection->sent_parsed;
    }
  }
}

/* flood_endgrace()
 *
 * marks the end of the clients grace period
 */
void
flood_endgrace(struct Client *client_p)
{
  SetFloodDone(client_p);

  /* Drop their flood limit back down */
  client_p->connection->allow_read = MAX_FLOOD;

  /*
   * sent_parsed could be way over MAX_FLOOD but under MAX_FLOOD_BURST,
   * so reset it.
   */
  client_p->connection->sent_parsed = 0;
}

/*
 * flood_recalc
 *
 * recalculate the number of allowed flood lines. this should be called
 * once a second on any given client. We then attempt to flush some data.
 */
void
flood_recalc(fde_t *fd, void *data)
{
  struct Client *const client_p = data;

  /*
   * Allow a bursting client their allocation per second, allow
   * a client whos flooding an extra 2 per second
   */
  if (IsFloodDone(client_p))
    client_p->connection->sent_parsed -= 2;
  else
    client_p->connection->sent_parsed = 0;

  if (client_p->connection->sent_parsed < 0)
    client_p->connection->sent_parsed = 0;

  parse_client_queued(client_p);

  /* And now, try flushing .. */
  if (!IsDead(client_p))
  {
    /* and finally, reset the flood check */
    comm_setflush(fd, 1000, flood_recalc, client_p);
  }
}

/*
 * read_packet - Read a 'packet' of data from a connection and process it.
 */
void
read_packet(fde_t *fd, void *data)
{
  struct Client *const client_p = data;
  int length = 0;

  if (IsDefunct(client_p))
    return;

  /*
   * Read some data. We *used to* do anti-flood protection here, but
   * I personally think it makes the code too hairy to make sane.
   *     -- adrian
   */
  do
  {
#ifdef HAVE_LIBCRYPTO
    if (fd->ssl)
    {
      length = SSL_read(fd->ssl, readBuf, sizeof(readBuf));

      /* translate openssl error codes, sigh */
      if (length < 0)
        switch (SSL_get_error(fd->ssl, length))
        {
          case SSL_ERROR_WANT_WRITE:
            comm_setselect(fd, COMM_SELECT_WRITE, sendq_unblocked, client_p, 0);
            return;
          case SSL_ERROR_WANT_READ:
              errno = EWOULDBLOCK;
          case SSL_ERROR_SYSCALL:
              break;
          case SSL_ERROR_SSL:
            if (errno == EAGAIN)
              break;
          default:
            length = errno = 0;
        }
    }
    else
#endif
    {
      length = recv(fd->fd, readBuf, sizeof(readBuf), 0);
    }

    if (length <= 0)
    {
      /*
       * If true, then we can recover from this error.  Just jump out of
       * the loop and re-register a new io-request.
       */
      if (length < 0 && ignoreErrno(errno))
        break;

      dead_link_on_read(client_p, length);
      return;
    }

    dbuf_put(&client_p->connection->buf_recvq, readBuf, length);

    if (client_p->connection->lasttime < CurrentTime)
      client_p->connection->lasttime = CurrentTime;

    if (client_p->connection->lasttime > client_p->connection->since)
      client_p->connection->since = CurrentTime;

    ClearPingSent(client_p);

    /* Attempt to parse what we have */
    parse_client_queued(client_p);

    if (IsDefunct(client_p))
      return;

    /* Check to make sure we're not flooding */
    if (!(IsServer(client_p) || IsHandshake(client_p) || IsConnecting(client_p)) &&
        (dbuf_length(&client_p->connection->buf_recvq) >
         get_recvq(&client_p->connection->confs)))
    {
      exit_client(client_p, "Excess Flood");
      return;
    }
  }
#ifdef HAVE_LIBCRYPTO
  while (length == sizeof(readBuf) || fd->ssl);
#else
  while (length == sizeof(readBuf));
#endif

  /* If we get here, we need to register for another COMM_SELECT_READ */
  comm_setselect(fd, COMM_SELECT_READ, read_packet, client_p, 0);
}
Revision:	4989
Committed:	Mon Dec 8 20:07:36 2014 UTC (10 years, 8 months ago) by michael
Content type:	text/x-csrc
File size:	10098 byte(s)
Log Message:	- The general::true_no_oper_flood configuration option has been deprecated. Operators still can have higher 'flood' limits with no_oper_flood = yes; hoewever, they are no longer allowed to bypass RecvQ limits.
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 1997-2014 ircd-hybrid development team
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation; either version 2 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	* USA
20	*/
21
22	/*! \file packet.c
23	* \brief Packet handlers.
24	* \version $Id$
25	*/
26
27	#include "stdinc.h"
28	#include "list.h"
29	#include "s_bsd.h"
30	#include "conf.h"
31	#include "server.h"
32	#include "client.h"
33	#include "ircd.h"
34	#include "parse.h"
35	#include "fdlist.h"
36	#include "packet.h"
37	#include "irc_string.h"
38	#include "memory.h"
39	#include "send.h"
40	#include "misc.h"
41
42	#define READBUF_SIZE 16384
43
44	static char readBuf[READBUF_SIZE];
45
46
47	/*
48	* client_dopacket - copy packet to client buf and parse it
49	* client_p - pointer to client structure for which the buffer data
50	* applies.
51	* buffer - pointr to the buffer containing the newly read data
52	* length - number of valid bytes of data in the buffer
53	*
54	* Note:
55	* It is implicitly assumed that client_dopacket() is called only
56	* with client_p of "local" variation, which contains all the
57	* necessary fields (buffer etc..)
58	*/
59	static void
60	client_dopacket(struct Client client_p, char buffer, size_t length)
61	{
62	/* Update messages received */
63	++me.connection->recv.messages;
64	++client_p->connection->recv.messages;
65
66	/* Update bytes received */
67	client_p->connection->recv.bytes += length;
68	me.connection->recv.bytes += length;
69
70	parse(client_p, buffer, buffer + length);
71	}
72
73	/* extract_one_line()
74	*
75	* inputs - pointer to a dbuf queue
76	* - pointer to buffer to copy data to
77	* output - length of <buffer>
78	* side effects - one line is copied and removed from the dbuf
79	*/
80	static int
81	extract_one_line(struct dbuf_queue qptr, char buffer)
82	{
83	int line_bytes = 0, empty_bytes = 0, phase = 0;
84	unsigned int idx = 0;
85	dlink_node *node = NULL;
86
87	/*
88	* Phase 0: "empty" characters before the line
89	* Phase 1: copying the line
90	* Phase 2: "empty" characters after the line
91	* (delete them as well and free some space in the dbuf)
92	*
93	* Empty characters are CR, LF and space (but, of course, not
94	* in the middle of a line). We try to remove as much of them as we can,
95	* since they simply eat server memory.
96	*
97	* --adx
98	*/
99	DLINK_FOREACH(node, qptr->blocks.head)
100	{
101	struct dbuf_block *block = node->data;
102
103	if (node == qptr->blocks.head)
104	idx = qptr->pos;
105	else
106	idx = 0;
107
108	for (; idx < block->size; ++idx)
109	{
110	char c = block->data[idx];
111
112	if (IsEol(c) \|\| (c == ' ' && phase != 1))
113	{
114	++empty_bytes;
115
116	if (phase == 1)
117	phase = 2;
118	}
119	else switch (phase)
120	{
121	case 0: phase = 1;
122	case 1: if (line_bytes++ < IRCD_BUFSIZE - 2)
123	*buffer++ = c;
124	break;
125	case 2: *buffer = '\0';
126	dbuf_delete(qptr, line_bytes + empty_bytes);
127	return IRCD_MIN(line_bytes, IRCD_BUFSIZE - 2);
128	}
129	}
130	}
131
132	/*
133	* Now, if we haven't reached phase 2, ignore all line bytes
134	* that we have read, since this is a partial line case.
135	*/
136	if (phase != 2)
137	line_bytes = 0;
138	else
139	*buffer = '\0';
140
141	/* Remove what is now unnecessary */
142	dbuf_delete(qptr, line_bytes + empty_bytes);
143	return IRCD_MIN(line_bytes, IRCD_BUFSIZE - 2);
144	}
145	/*
146	* parse_client_queued - parse client queued messages
147	*/
148	static void
149	parse_client_queued(struct Client *client_p)
150	{
151	int dolen = 0;
152
153	if (IsUnknown(client_p))
154	{
155	unsigned int i = 0;
156
157	while (1)
158	{
159	if (IsDefunct(client_p))
160	return;
161
162	/* Rate unknown clients at MAX_FLOOD per loop */
163	if (i >= MAX_FLOOD)
164	break;
165
166	dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);
167
168	if (dolen == 0)
169	break;
170
171	client_dopacket(client_p, readBuf, dolen);
172	++i;
173
174	/*
175	* If they've dropped out of the unknown state, break and move
176	* to the parsing for their appropriate status. --fl
177	*/
178	if (!IsUnknown(client_p))
179	break;
180	}
181	}
182
183	if (IsServer(client_p) \|\| IsConnecting(client_p) \|\| IsHandshake(client_p))
184	{
185	while (1)
186	{
187	if (IsDefunct(client_p))
188	return;
189
190	if ((dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf)) == 0)
191	break;
192
193	client_dopacket(client_p, readBuf, dolen);
194	}
195	}
196	else if (IsClient(client_p))
197	{
198	unsigned int checkflood = 1;
199
200	if (ConfigGeneral.no_oper_flood && HasUMode(client_p, UMODE_OPER))
201	checkflood = 0;
202	else if (IsCanFlood(client_p))
203	checkflood = 0;
204
205	/*
206	* Handle flood protection here - if we exceed our flood limit on
207	* messages in this loop, we simply drop out of the loop prematurely.
208	* -- adrian
209	*/
210	while (1)
211	{
212	if (IsDefunct(client_p))
213	break;
214
215	/*
216	* This flood protection works as follows:
217	*
218	* A client is given allow_read lines to send to the server. Every
219	* time a line is parsed, sent_parsed is increased. sent_parsed
220	* is decreased by 1 every time flood_recalc is called.
221	*
222	* Thus a client can 'burst' allow_read lines to the server, any
223	* excess lines will be parsed one per flood_recalc() call.
224	*
225	* Therefore a client will be penalised more if they keep flooding,
226	* as sent_parsed will always hover around the allow_read limit
227	* and no 'bursts' will be permitted.
228	*/
229	if (checkflood)
230	if (client_p->connection->sent_parsed >= client_p->connection->allow_read)
231	break;
232
233	dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);
234
235	if (dolen == 0)
236	break;
237
238	client_dopacket(client_p, readBuf, dolen);
239	++client_p->connection->sent_parsed;
240	}
241	}
242	}
243
244	/* flood_endgrace()
245	*
246	* marks the end of the clients grace period
247	*/
248	void
249	flood_endgrace(struct Client *client_p)
250	{
251	SetFloodDone(client_p);
252
253	/* Drop their flood limit back down */
254	client_p->connection->allow_read = MAX_FLOOD;
255
256	/*
257	* sent_parsed could be way over MAX_FLOOD but under MAX_FLOOD_BURST,
258	* so reset it.
259	*/
260	client_p->connection->sent_parsed = 0;
261	}
262
263	/*
264	* flood_recalc
265	*
266	* recalculate the number of allowed flood lines. this should be called
267	* once a second on any given client. We then attempt to flush some data.
268	*/
269	void
270	flood_recalc(fde_t fd, void data)
271	{
272	struct Client *const client_p = data;
273
274	/*
275	* Allow a bursting client their allocation per second, allow
276	* a client whos flooding an extra 2 per second
277	*/
278	if (IsFloodDone(client_p))
279	client_p->connection->sent_parsed -= 2;
280	else
281	client_p->connection->sent_parsed = 0;
282
283	if (client_p->connection->sent_parsed < 0)
284	client_p->connection->sent_parsed = 0;
285
286	parse_client_queued(client_p);
287
288	/* And now, try flushing .. */
289	if (!IsDead(client_p))
290	{
291	/* and finally, reset the flood check */
292	comm_setflush(fd, 1000, flood_recalc, client_p);
293	}
294	}
295
296	/*
297	* read_packet - Read a 'packet' of data from a connection and process it.
298	*/
299	void
300	read_packet(fde_t fd, void data)
301	{
302	struct Client *const client_p = data;
303	int length = 0;
304
305	if (IsDefunct(client_p))
306	return;
307
308	/*
309	* Read some data. We used to do anti-flood protection here, but
310	* I personally think it makes the code too hairy to make sane.
311	* -- adrian
312	*/
313	do
314	{
315	#ifdef HAVE_LIBCRYPTO
316	if (fd->ssl)
317	{
318	length = SSL_read(fd->ssl, readBuf, sizeof(readBuf));
319
320	/* translate openssl error codes, sigh */
321	if (length < 0)
322	switch (SSL_get_error(fd->ssl, length))
323	{
324	case SSL_ERROR_WANT_WRITE:
325	comm_setselect(fd, COMM_SELECT_WRITE, sendq_unblocked, client_p, 0);
326	return;
327	case SSL_ERROR_WANT_READ:
328	errno = EWOULDBLOCK;
329	case SSL_ERROR_SYSCALL:
330	break;
331	case SSL_ERROR_SSL:
332	if (errno == EAGAIN)
333	break;
334	default:
335	length = errno = 0;
336	}
337	}
338	else
339	#endif
340	{
341	length = recv(fd->fd, readBuf, sizeof(readBuf), 0);
342	}
343
344	if (length <= 0)
345	{
346	/*
347	* If true, then we can recover from this error. Just jump out of
348	* the loop and re-register a new io-request.
349	*/
350	if (length < 0 && ignoreErrno(errno))
351	break;
352
353	dead_link_on_read(client_p, length);
354	return;
355	}
356
357	dbuf_put(&client_p->connection->buf_recvq, readBuf, length);
358
359	if (client_p->connection->lasttime < CurrentTime)
360	client_p->connection->lasttime = CurrentTime;
361
362	if (client_p->connection->lasttime > client_p->connection->since)
363	client_p->connection->since = CurrentTime;
364
365	ClearPingSent(client_p);
366
367	/* Attempt to parse what we have */
368	parse_client_queued(client_p);
369
370	if (IsDefunct(client_p))
371	return;
372
373	/* Check to make sure we're not flooding */
374	if (!(IsServer(client_p) \|\| IsHandshake(client_p) \|\| IsConnecting(client_p)) &&
375	(dbuf_length(&client_p->connection->buf_recvq) >
376	get_recvq(&client_p->connection->confs)))
377	{
378	exit_client(client_p, "Excess Flood");
379	return;
380	}
381	}
382	#ifdef HAVE_LIBCRYPTO
383	while (length == sizeof(readBuf) \|\| fd->ssl);
384	#else
385	while (length == sizeof(readBuf));
386	#endif
387
388	/* If we get here, we need to register for another COMM_SELECT_READ */
389	comm_setselect(fd, COMM_SELECT_READ, read_packet, client_p, 0);
390	}