1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35#if 0
36static char sccsid[] = "@(#)table.c	8.1 (Berkeley) 6/4/93";
37#endif
38__attribute__((__used__))
39static const char rcsid[] =
40  "$FreeBSD: src/libexec/talkd/table.c,v 1.9 2003/04/03 05:13:27 jmallett Exp $";
41#endif /* not lint */
42
43#include <sys/cdefs.h>
44
45/*
46 * Routines to handle insertion, deletion, etc on the table
47 * of requests kept by the daemon. Nothing fancy here, linear
48 * search on a double-linked list. A time is kept with each
49 * entry so that overly old invitations can be eliminated.
50 *
51 * Consider this a mis-guided attempt at modularity
52 */
53#include <sys/param.h>
54#include <sys/time.h>
55#include <sys/socket.h>
56#include <netinet/in.h>
57#include <protocols/talkd.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <syslog.h>
62#include <unistd.h>
63
64#include "extern.h"
65
66#define MAX_ID 16000	/* << 2^15 so I don't have sign troubles */
67
68#define NIL ((TABLE_ENTRY *)0)
69
70extern	int debug;
71struct	timeval tp;
72struct	timezone txp;
73
74typedef struct table_entry TABLE_ENTRY;
75
76struct table_entry {
77	CTL_MSG request;
78	long	time;
79	TABLE_ENTRY *next;
80	TABLE_ENTRY *last;
81};
82
83static void delete(TABLE_ENTRY *);
84
85TABLE_ENTRY *table = NIL;
86
87/*
88 * Look in the table for an invitation that matches the current
89 * request looking for an invitation
90 */
91CTL_MSG *
92find_match(CTL_MSG *request)
93{
94	TABLE_ENTRY *ptr;
95	time_t current_time;
96
97	gettimeofday(&tp, &txp);
98	current_time = tp.tv_sec;
99	if (debug)
100		print_request("find_match", request);
101	for (ptr = table; ptr != NIL; ptr = ptr->next) {
102		if ((ptr->time - current_time) > MAX_LIFE) {
103			/* the entry is too old */
104			if (debug)
105				print_request("deleting expired entry",
106				    &ptr->request);
107			delete(ptr);
108			continue;
109		}
110		if (debug)
111			print_request("", &ptr->request);
112		if (strcmp(request->l_name, ptr->request.r_name) == 0 &&
113		    strcmp(request->r_name, ptr->request.l_name) == 0 &&
114		     ptr->request.type == LEAVE_INVITE)
115			return (&ptr->request);
116	}
117	return ((CTL_MSG *)0);
118}
119
120/*
121 * Look for an identical request, as opposed to a complimentary
122 * one as find_match does
123 */
124CTL_MSG *
125find_request(CTL_MSG *request)
126{
127	TABLE_ENTRY *ptr;
128	time_t current_time;
129
130	gettimeofday(&tp, &txp);
131	current_time = tp.tv_sec;
132	/*
133	 * See if this is a repeated message, and check for
134	 * out of date entries in the table while we are it.
135	 */
136	if (debug)
137		print_request("find_request", request);
138	for (ptr = table; ptr != NIL; ptr = ptr->next) {
139		if ((ptr->time - current_time) > MAX_LIFE) {
140			/* the entry is too old */
141			if (debug)
142				print_request("deleting expired entry",
143				    &ptr->request);
144			delete(ptr);
145			continue;
146		}
147		if (debug)
148			print_request("", &ptr->request);
149		if (strcmp(request->r_name, ptr->request.r_name) == 0 &&
150		    strcmp(request->l_name, ptr->request.l_name) == 0 &&
151		    request->type == ptr->request.type &&
152		    request->pid == ptr->request.pid) {
153			/* update the time if we 'touch' it */
154			ptr->time = current_time;
155			return (&ptr->request);
156		}
157	}
158	return ((CTL_MSG *)0);
159}
160
161void
162insert_table(CTL_MSG *request, CTL_RESPONSE *response)
163{
164	TABLE_ENTRY *ptr;
165	time_t current_time;
166
167	gettimeofday(&tp, &txp);
168	current_time = tp.tv_sec;
169	request->id_num = new_id();
170	response->id_num = htonl(request->id_num);
171	/* insert a new entry into the top of the list */
172	ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY));
173	if (ptr == NIL) {
174		syslog(LOG_ERR, "insert_table: Out of memory");
175		_exit(1);
176	}
177	ptr->time = current_time;
178	ptr->request = *request;
179	ptr->next = table;
180	if (ptr->next != NIL)
181		ptr->next->last = ptr;
182	ptr->last = NIL;
183	table = ptr;
184}
185
186/*
187 * Generate a unique non-zero sequence number
188 */
189int
190new_id(void)
191{
192	static int current_id = 0;
193
194	current_id = (current_id + 1) % MAX_ID;
195	/* 0 is reserved, helps to pick up bugs */
196	if (current_id == 0)
197		current_id = 1;
198	return (current_id);
199}
200
201/*
202 * Delete the invitation with id 'id_num'
203 */
204int
205delete_invite(u_int32_t id_num)
206{
207	TABLE_ENTRY *ptr;
208
209	ptr = table;
210	if (debug)
211		syslog(LOG_DEBUG, "delete_invite(%d)", id_num);
212	for (ptr = table; ptr != NIL; ptr = ptr->next) {
213		if (ptr->request.id_num == id_num)
214			break;
215		if (debug)
216			print_request("", &ptr->request);
217	}
218	if (ptr != NIL) {
219		delete(ptr);
220		return (SUCCESS);
221	}
222	return (NOT_HERE);
223}
224
225/*
226 * Classic delete from a double-linked list
227 */
228static void
229delete(TABLE_ENTRY *ptr)
230{
231
232	if (debug)
233		print_request("delete", &ptr->request);
234	if (table == ptr)
235		table = ptr->next;
236	else if (ptr->last != NIL)
237		ptr->last->next = ptr->next;
238	if (ptr->next != NIL)
239		ptr->next->last = ptr->last;
240	free((char *)ptr);
241}
242