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