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 * 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 * 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 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 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 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 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