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
36 static char sccsid[] = "@(#)table.c 8.1 (Berkeley) 6/4/93";
37 #endif
38 static const char rcsid[] =
39 "$FreeBSD: stable/9/libexec/talkd/table.c 211056 2010-08-08 02:45:48Z ed $";
40 #endif /* not lint */
41
42 /*
43 * Routines to handle insertion, deletion, etc on the table
44 * of requests kept by the daemon. Nothing fancy here, linear
45 * search on a double-linked list. A time is kept with each
46 * entry so that overly old invitations can be eliminated.
47 *
48 * Consider this a mis-guided attempt at modularity
49 */
50 #include <sys/param.h>
51 #include <sys/time.h>
52 #include <sys/socket.h>
53 #include <netinet/in.h>
54 #include <protocols/talkd.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <syslog.h>
59 #include <unistd.h>
60
61 #include "extern.h"
62
63 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */
64
65 #define NIL ((TABLE_ENTRY *)0)
66
67 extern int debug;
68 struct timeval tp;
69
70 typedef struct table_entry TABLE_ENTRY;
71
72 struct table_entry {
73 CTL_MSG request;
74 long time;
75 TABLE_ENTRY *next;
76 TABLE_ENTRY *last;
77 };
78
79 static void delete(TABLE_ENTRY *);
80
81 TABLE_ENTRY *table = NIL;
82
83 /*
84 * Look in the table for an invitation that matches the current
85 * request looking for an invitation
86 */
87 CTL_MSG *
find_match(CTL_MSG * request)88 find_match(CTL_MSG *request)
89 {
90 TABLE_ENTRY *ptr;
91 time_t current_time;
92
93 gettimeofday(&tp, NULL);
94 current_time = tp.tv_sec;
95 if (debug)
96 print_request("find_match", request);
97 for (ptr = table; ptr != NIL; ptr = ptr->next) {
98 if ((ptr->time - current_time) > MAX_LIFE) {
99 /* the entry is too old */
100 if (debug)
101 print_request("deleting expired entry",
102 &ptr->request);
103 delete(ptr);
104 continue;
105 }
106 if (debug)
107 print_request("", &ptr->request);
108 if (strcmp(request->l_name, ptr->request.r_name) == 0 &&
109 strcmp(request->r_name, ptr->request.l_name) == 0 &&
110 ptr->request.type == LEAVE_INVITE)
111 return (&ptr->request);
112 }
113 return ((CTL_MSG *)0);
114 }
115
116 /*
117 * Look for an identical request, as opposed to a complimentary
118 * one as find_match does
119 */
120 CTL_MSG *
find_request(CTL_MSG * request)121 find_request(CTL_MSG *request)
122 {
123 TABLE_ENTRY *ptr;
124 time_t current_time;
125
126 gettimeofday(&tp, NULL);
127 current_time = tp.tv_sec;
128 /*
129 * See if this is a repeated message, and check for
130 * out of date entries in the table while we are it.
131 */
132 if (debug)
133 print_request("find_request", request);
134 for (ptr = table; ptr != NIL; ptr = ptr->next) {
135 if ((ptr->time - current_time) > MAX_LIFE) {
136 /* the entry is too old */
137 if (debug)
138 print_request("deleting expired entry",
139 &ptr->request);
140 delete(ptr);
141 continue;
142 }
143 if (debug)
144 print_request("", &ptr->request);
145 if (strcmp(request->r_name, ptr->request.r_name) == 0 &&
146 strcmp(request->l_name, ptr->request.l_name) == 0 &&
147 request->type == ptr->request.type &&
148 request->pid == ptr->request.pid) {
149 /* update the time if we 'touch' it */
150 ptr->time = current_time;
151 return (&ptr->request);
152 }
153 }
154 return ((CTL_MSG *)0);
155 }
156
157 void
insert_table(CTL_MSG * request,CTL_RESPONSE * response)158 insert_table(CTL_MSG *request, CTL_RESPONSE *response)
159 {
160 TABLE_ENTRY *ptr;
161 time_t current_time;
162
163 gettimeofday(&tp, NULL);
164 current_time = tp.tv_sec;
165 request->id_num = new_id();
166 response->id_num = htonl(request->id_num);
167 /* insert a new entry into the top of the list */
168 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY));
169 if (ptr == NIL) {
170 syslog(LOG_ERR, "insert_table: Out of memory");
171 _exit(1);
172 }
173 ptr->time = current_time;
174 ptr->request = *request;
175 ptr->next = table;
176 if (ptr->next != NIL)
177 ptr->next->last = ptr;
178 ptr->last = NIL;
179 table = ptr;
180 }
181
182 /*
183 * Generate a unique non-zero sequence number
184 */
185 int
new_id(void)186 new_id(void)
187 {
188 static int current_id = 0;
189
190 current_id = (current_id + 1) % MAX_ID;
191 /* 0 is reserved, helps to pick up bugs */
192 if (current_id == 0)
193 current_id = 1;
194 return (current_id);
195 }
196
197 /*
198 * Delete the invitation with id 'id_num'
199 */
200 int
delete_invite(u_int32_t id_num)201 delete_invite(u_int32_t id_num)
202 {
203 TABLE_ENTRY *ptr;
204
205 ptr = table;
206 if (debug)
207 syslog(LOG_DEBUG, "delete_invite(%d)", id_num);
208 for (ptr = table; ptr != NIL; ptr = ptr->next) {
209 if (ptr->request.id_num == id_num)
210 break;
211 if (debug)
212 print_request("", &ptr->request);
213 }
214 if (ptr != NIL) {
215 delete(ptr);
216 return (SUCCESS);
217 }
218 return (NOT_HERE);
219 }
220
221 /*
222 * Classic delete from a double-linked list
223 */
224 static void
delete(TABLE_ENTRY * ptr)225 delete(TABLE_ENTRY *ptr)
226 {
227
228 if (debug)
229 print_request("delete", &ptr->request);
230 if (table == ptr)
231 table = ptr->next;
232 else if (ptr->last != NIL)
233 ptr->last->next = ptr->next;
234 if (ptr->next != NIL)
235 ptr->next->last = ptr->last;
236 free((char *)ptr);
237 }
238