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