trunk/src/packet.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2018 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"


enum { 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 - pointer 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, unsigned int 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 size_t
extract_one_line(struct dbuf_queue *qptr, char *buffer)
{
  size_t line_bytes = 0, eol_bytes = 0;
  dlink_node *node;

  DLINK_FOREACH(node, qptr->blocks.head)
  {
    const struct dbuf_block *block = node->data;
    unsigned int idx;

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

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

      if (IsEol(c))
      {
        ++eol_bytes;

        /* Allow 2 eol bytes per message */
        if (eol_bytes == 2)
          goto out;
      }
      else if (eol_bytes)
        goto out;
      else if (line_bytes++ < IRCD_BUFSIZE - 2)
        *buffer++ = c;
    }
  }

out:

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

  /* Remove what is now unnecessary */
  dbuf_delete(qptr, line_bytes + eol_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)
{
  if (IsUnknown(client_p))
  {
    unsigned int i = 0;

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

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

      size_t 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 (true)
    {
      if (IsDefunct(client_p))
        return;

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

      client_dopacket(client_p, readBuf, dolen);
    }
  }
  else if (IsClient(client_p))
  {
    bool checkflood = true;

    if (ConfigGeneral.no_oper_flood && HasUMode(client_p, UMODE_OPER))
      checkflood = false;
    else if (HasFlag(client_p, FLAGS_CANFLOOD))
      checkflood = false;

    /*
     * 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 (true)
    {
      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 == true)
        if (client_p->connection->sent_parsed >= (IsFloodDone(client_p) ? MAX_FLOOD : MAX_FLOOD_BURST))
          break;

      size_t 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)
{
  if (IsFloodDone(client_p))
    return;  /* Grace period has already ended */

  AddFlag(client_p, FLAGS_FLOODDONE);

  /*
   * 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 *F, void *data)
{
  struct Client *const client_p = data;

  /*
   * Allow a bursting client their allocation per second, allow
   * a client who is 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(F, 1000, flood_recalc, client_p);
  }
}

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

  assert(client_p);
  assert(client_p->connection);
  assert(client_p->connection->fd);
  assert(client_p->connection->fd == F);

  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
  {
    if (tls_isusing(&F->ssl))
    {
      bool want_write = false;
      length = tls_read(&F->ssl, readBuf, sizeof(readBuf), &want_write);

      if (want_write == true)
        comm_setselect(F, COMM_SELECT_WRITE, sendq_unblocked, client_p, 0);
    }
    else
      length = recv(F->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 && comm_ignore_errno(errno) == true)
        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;

    DelFlag(client_p, FLAGS_PINGSENT);

    /* 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;
    }
  } while (length == sizeof(readBuf) || tls_isusing(&F->ssl));

  /* If we get here, we need to register for another COMM_SELECT_READ */
  comm_setselect(F, COMM_SELECT_READ, read_packet, client_p, 0);
}
Revision:	8715
Committed:	Sun Dec 9 20:17:02 2018 UTC (7 years, 9 months ago) by michael
Content type:	text/x-csrc
File size:	9233 byte(s)
Log Message:	- Rewrites to have parse_handle_command() end the flood grace period. MODE and TIME no longer ends the grace period.
#	User	Rev	Content
1	adx	30	/*
2	michael	2916	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	adx	30	*
4	michael	8279	* Copyright (c) 1997-2018 ircd-hybrid development team
5	adx	30	*
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	michael	4565	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	adx	30	* USA
20			*/
21	michael	2916
22			/*! \file packet.c
23			* \brief Packet handlers.
24			* \version $Id$
25			*/
26
27	adx	30	#include "stdinc.h"
28	michael	1011	#include "list.h"
29	adx	30	#include "s_bsd.h"
30	michael	1309	#include "conf.h"
31	michael	3347	#include "server.h"
32	adx	30	#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	michael	3347	#include "misc.h"
41	adx	30
42	michael	6527
43	michael	6350	enum { READBUF_SIZE = 16384 };
44	adx	30
45			static char readBuf[READBUF_SIZE];
46
47	michael	4982
48			/*
49			* client_dopacket - copy packet to client buf and parse it
50			* client_p - pointer to client structure for which the buffer data
51			* applies.
52	michael	6517	* buffer - pointer to the buffer containing the newly read data
53	michael	4982	* length - number of valid bytes of data in the buffer
54			*
55			* Note:
56	michael	4989	* It is implicitly assumed that client_dopacket() is called only
57	michael	4982	* with client_p of "local" variation, which contains all the
58			* necessary fields (buffer etc..)
59			*/
60			static void
61	michael	5422	client_dopacket(struct Client client_p, char buffer, unsigned int length)
62	michael	4982	{
63			/* Update messages received */
64			++me.connection->recv.messages;
65			++client_p->connection->recv.messages;
66
67			/* Update bytes received */
68			client_p->connection->recv.bytes += length;
69			me.connection->recv.bytes += length;
70
71			parse(client_p, buffer, buffer + length);
72			}
73
74	adx	30	/* extract_one_line()
75			*
76			* inputs - pointer to a dbuf queue
77			* - pointer to buffer to copy data to
78			* output - length of <buffer>
79			* side effects - one line is copied and removed from the dbuf
80			*/
81	michael	8709	static size_t
82	adx	30	extract_one_line(struct dbuf_queue qptr, char buffer)
83			{
84	michael	8709	size_t line_bytes = 0, eol_bytes = 0;
85	michael	5421	dlink_node *node;
86	adx	30
87	michael	5421	DLINK_FOREACH(node, qptr->blocks.head)
88	adx	30	{
89	michael	5421	const struct dbuf_block *block = node->data;
90	michael	5413	unsigned int idx;
91	adx	30
92	michael	5421	if (node == qptr->blocks.head)
93	michael	3107	idx = qptr->pos;
94			else
95			idx = 0;
96
97			for (; idx < block->size; ++idx)
98	adx	30	{
99	michael	3107	char c = block->data[idx];
100
101	michael	5413	if (IsEol(c))
102	adx	30	{
103	michael	5413	++eol_bytes;
104	michael	3453
105	michael	5413	/* Allow 2 eol bytes per message */
106			if (eol_bytes == 2)
107			goto out;
108	adx	30	}
109	michael	5413	else if (eol_bytes)
110			goto out;
111			else if (line_bytes++ < IRCD_BUFSIZE - 2)
112			*buffer++ = c;
113	adx	30	}
114			}
115
116	michael	5413	out:
117
118	adx	30	/*
119	michael	5413	* Now, if we haven't found an EOL, ignore all line bytes
120	adx	30	* that we have read, since this is a partial line case.
121			*/
122	michael	5413	if (eol_bytes)
123			*buffer = '\0';
124			else
125	adx	30	line_bytes = 0;
126
127			/* Remove what is now unnecessary */
128	michael	5413	dbuf_delete(qptr, line_bytes + eol_bytes);
129
130	adx	30	return IRCD_MIN(line_bytes, IRCD_BUFSIZE - 2);
131			}
132	michael	5413
133	adx	30	/*
134			* parse_client_queued - parse client queued messages
135			*/
136			static void
137			parse_client_queued(struct Client *client_p)
138	michael	2916	{
139	adx	30	if (IsUnknown(client_p))
140			{
141	michael	4982	unsigned int i = 0;
142	adx	30
143	michael	8664	while (true)
144	adx	30	{
145			if (IsDefunct(client_p))
146	michael	2916	return;
147	adx	30
148	michael	4982	/* Rate unknown clients at MAX_FLOOD per loop */
149	adx	30	if (i >= MAX_FLOOD)
150			break;
151
152	michael	8709	size_t dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);
153	adx	30	if (dolen == 0)
154	michael	2916	break;
155	adx	30
156			client_dopacket(client_p, readBuf, dolen);
157	michael	4982	++i;
158	adx	30
159	michael	4982	/*
160			* If they've dropped out of the unknown state, break and move
161	adx	30	* to the parsing for their appropriate status. --fl
162			*/
163	michael	3453	if (!IsUnknown(client_p))
164	adx	30	break;
165			}
166			}
167
168			if (IsServer(client_p) \|\| IsConnecting(client_p) \|\| IsHandshake(client_p))
169			{
170	michael	8664	while (true)
171	adx	30	{
172			if (IsDefunct(client_p))
173			return;
174	michael	4890
175	michael	8709	size_t dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);
176			if (dolen == 0)
177	adx	30	break;
178	michael	3453
179	adx	30	client_dopacket(client_p, readBuf, dolen);
180			}
181			}
182	adx	163	else if (IsClient(client_p))
183	adx	30	{
184	michael	8660	bool checkflood = true;
185	adx	30
186	michael	4989	if (ConfigGeneral.no_oper_flood && HasUMode(client_p, UMODE_OPER))
187	michael	8660	checkflood = false;
188	michael	6313	else if (HasFlag(client_p, FLAGS_CANFLOOD))
189	michael	8660	checkflood = false;
190	michael	4989
191	adx	30	/*
192	michael	5545	* Handle flood protection here - if we exceed our flood limit on messages
193			* in this loop, we simply drop out of the loop prematurely.
194	adx	30	* -- adrian
195			*/
196	michael	8664	while (true)
197	adx	30	{
198			if (IsDefunct(client_p))
199	michael	2916	break;
200	adx	30
201	michael	4982	/*
202			* This flood protection works as follows:
203	adx	30	*
204			* A client is given allow_read lines to send to the server. Every
205			* time a line is parsed, sent_parsed is increased. sent_parsed
206			* is decreased by 1 every time flood_recalc is called.
207			*
208			* Thus a client can 'burst' allow_read lines to the server, any
209			* excess lines will be parsed one per flood_recalc() call.
210			*
211			* Therefore a client will be penalised more if they keep flooding,
212			* as sent_parsed will always hover around the allow_read limit
213			* and no 'bursts' will be permitted.
214			*/
215	michael	8660	if (checkflood == true)
216	michael	8710	if (client_p->connection->sent_parsed >= (IsFloodDone(client_p) ? MAX_FLOOD : MAX_FLOOD_BURST))
217	adx	30	break;
218	michael	2916
219	michael	8709	size_t dolen = extract_one_line(&client_p->connection->buf_recvq, readBuf);
220	adx	30	if (dolen == 0)
221			break;
222
223			client_dopacket(client_p, readBuf, dolen);
224	michael	4982	++client_p->connection->sent_parsed;
225	adx	30	}
226			}
227			}
228
229			/* flood_endgrace()
230			*
231			* marks the end of the clients grace period
232			*/
233			void
234			flood_endgrace(struct Client *client_p)
235			{
236	michael	8715	if (IsFloodDone(client_p))
237			return; /* Grace period has already ended */
238
239	michael	6313	AddFlag(client_p, FLAGS_FLOODDONE);
240	adx	30
241	michael	4982	/*
242			* sent_parsed could be way over MAX_FLOOD but under MAX_FLOOD_BURST,
243	adx	30	* so reset it.
244			*/
245	michael	4588	client_p->connection->sent_parsed = 0;
246	adx	30	}
247
248			/*
249			* flood_recalc
250			*
251			* recalculate the number of allowed flood lines. this should be called
252			* once a second on any given client. We then attempt to flush some data.
253			*/
254			void
255	michael	8339	flood_recalc(fde_t F, void data)
256	adx	30	{
257	michael	4982	struct Client *const client_p = data;
258	michael	2916
259	michael	4890	/*
260			* Allow a bursting client their allocation per second, allow
261	michael	6520	* a client who is flooding an extra 2 per second
262	adx	30	*/
263			if (IsFloodDone(client_p))
264	michael	4982	client_p->connection->sent_parsed -= 2;
265	adx	30	else
266	michael	4982	client_p->connection->sent_parsed = 0;
267	michael	2916
268	michael	4982	if (client_p->connection->sent_parsed < 0)
269			client_p->connection->sent_parsed = 0;
270	michael	2916
271	adx	30	parse_client_queued(client_p);
272	michael	2916
273	adx	30	/* And now, try flushing .. */
274			if (!IsDead(client_p))
275			{
276			/* and finally, reset the flood check */
277	michael	8339	comm_setflush(F, 1000, flood_recalc, client_p);
278	adx	30	}
279			}
280
281			/*
282			* read_packet - Read a 'packet' of data from a connection and process it.
283			*/
284			void
285	michael	8339	read_packet(fde_t F, void data)
286	adx	30	{
287	michael	4982	struct Client *const client_p = data;
288	adx	30	int length = 0;
289
290	michael	8339	assert(client_p);
291			assert(client_p->connection);
292			assert(client_p->connection->fd);
293			assert(client_p->connection->fd == F);
294
295	adx	30	if (IsDefunct(client_p))
296			return;
297
298			/*
299			* Read some data. We used to do anti-flood protection here, but
300			* I personally think it makes the code too hairy to make sane.
301			* -- adrian
302			*/
303	michael	2916	do
304			{
305	michael	8339	if (tls_isusing(&F->ssl))
306	adx	30	{
307	michael	8660	bool want_write = false;
308	michael	8339	length = tls_read(&F->ssl, readBuf, sizeof(readBuf), &want_write);
309	adx	30
310	michael	8660	if (want_write == true)
311	michael	8339	comm_setselect(F, COMM_SELECT_WRITE, sendq_unblocked, client_p, 0);
312	adx	30	}
313			else
314	michael	8339	length = recv(F->fd, readBuf, sizeof(readBuf), 0);
315	adx	30
316			if (length <= 0)
317			{
318			/*
319	michael	5545	* If true, then we can recover from this error. Just jump out of
320	adx	30	* the loop and re-register a new io-request.
321			*/
322	michael	8660	if (length < 0 && comm_ignore_errno(errno) == true)
323	adx	30	break;
324
325			dead_link_on_read(client_p, length);
326			return;
327			}
328
329	michael	4588	dbuf_put(&client_p->connection->buf_recvq, readBuf, length);
330	adx	30
331	michael	4588	if (client_p->connection->lasttime < CurrentTime)
332			client_p->connection->lasttime = CurrentTime;
333	michael	4890
334	michael	4588	if (client_p->connection->lasttime > client_p->connection->since)
335			client_p->connection->since = CurrentTime;
336	michael	3453
337	michael	6313	DelFlag(client_p, FLAGS_PINGSENT);
338	adx	30
339			/* Attempt to parse what we have */
340			parse_client_queued(client_p);
341
342			if (IsDefunct(client_p))
343			return;
344
345			/* Check to make sure we're not flooding */
346	michael	4989	if (!(IsServer(client_p) \|\| IsHandshake(client_p) \|\| IsConnecting(client_p)) &&
347			(dbuf_length(&client_p->connection->buf_recvq) >
348			get_recvq(&client_p->connection->confs)))
349	adx	30	{
350	michael	4989	exit_client(client_p, "Excess Flood");
351			return;
352	adx	30	}
353	michael	8339	} while (length == sizeof(readBuf) \|\| tls_isusing(&F->ssl));
354	adx	30
355			/* If we get here, we need to register for another COMM_SELECT_READ */
356	michael	8339	comm_setselect(F, COMM_SELECT_READ, read_packet, client_p, 0);
357	adx	30	}