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 /* 33 * Routines to handle insertion, deletion, etc on the table 34 * of requests kept by the daemon. Nothing fancy here, linear 35 * search on a double-linked list. A time is kept with each 36 * entry so that overly old invitations can be eliminated. 37 * 38 * Consider this a mis-guided attempt at modularity 39 */ 40 #include <sys/param.h> 41 #include <sys/time.h> 42 #include <sys/socket.h> 43 #include <netinet/in.h> 44 #include <protocols/talkd.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <syslog.h> 49 #include <unistd.h> 50 51 #include "extern.h" 52 53 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ 54 55 #define NIL ((TABLE_ENTRY *)0) 56 57 static struct timespec ts; 58 59 typedef struct table_entry TABLE_ENTRY; 60 61 struct table_entry { 62 CTL_MSG request; 63 long time; 64 TABLE_ENTRY *next; 65 TABLE_ENTRY *last; 66 }; 67 68 static void delete(TABLE_ENTRY *); 69 70 static TABLE_ENTRY *table = NIL; 71 72 /* 73 * Look in the table for an invitation that matches the current 74 * request looking for an invitation 75 */ 76 CTL_MSG * 77 find_match(CTL_MSG *request) 78 { 79 TABLE_ENTRY *ptr, *next; 80 time_t current_time; 81 82 clock_gettime(CLOCK_MONOTONIC_FAST, &ts); 83 current_time = ts.tv_sec; 84 if (debug) 85 print_request("find_match", request); 86 for (ptr = table; ptr != NIL; ptr = next) { 87 next = ptr->next; 88 if ((ptr->time - current_time) > MAX_LIFE) { 89 /* the entry is too old */ 90 if (debug) 91 print_request("deleting expired entry", 92 &ptr->request); 93 delete(ptr); 94 continue; 95 } 96 if (debug) 97 print_request("", &ptr->request); 98 if (strcmp(request->l_name, ptr->request.r_name) == 0 && 99 strcmp(request->r_name, ptr->request.l_name) == 0 && 100 ptr->request.type == LEAVE_INVITE) 101 return (&ptr->request); 102 } 103 return ((CTL_MSG *)0); 104 } 105 106 /* 107 * Look for an identical request, as opposed to a complimentary 108 * one as find_match does 109 */ 110 CTL_MSG * 111 find_request(CTL_MSG *request) 112 { 113 TABLE_ENTRY *ptr, *next; 114 time_t current_time; 115 116 clock_gettime(CLOCK_MONOTONIC_FAST, &ts); 117 current_time = ts.tv_sec; 118 /* 119 * See if this is a repeated message, and check for 120 * out of date entries in the table while we are it. 121 */ 122 if (debug) 123 print_request("find_request", request); 124 for (ptr = table; ptr != NIL; ptr = next) { 125 next = ptr->next; 126 if ((ptr->time - current_time) > MAX_LIFE) { 127 /* the entry is too old */ 128 if (debug) 129 print_request("deleting expired entry", 130 &ptr->request); 131 delete(ptr); 132 continue; 133 } 134 if (debug) 135 print_request("", &ptr->request); 136 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 137 strcmp(request->l_name, ptr->request.l_name) == 0 && 138 request->type == ptr->request.type && 139 request->pid == ptr->request.pid) { 140 /* update the time if we 'touch' it */ 141 ptr->time = current_time; 142 return (&ptr->request); 143 } 144 } 145 return ((CTL_MSG *)0); 146 } 147 148 void 149 insert_table(CTL_MSG *request, CTL_RESPONSE *response) 150 { 151 TABLE_ENTRY *ptr; 152 time_t current_time; 153 154 clock_gettime(CLOCK_MONOTONIC_FAST, &ts); 155 current_time = ts.tv_sec; 156 request->id_num = new_id(); 157 response->id_num = htonl(request->id_num); 158 /* insert a new entry into the top of the list */ 159 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 160 if (ptr == NIL) { 161 syslog(LOG_ERR, "insert_table: Out of memory"); 162 _exit(1); 163 } 164 ptr->time = current_time; 165 ptr->request = *request; 166 ptr->next = table; 167 if (ptr->next != NIL) 168 ptr->next->last = ptr; 169 ptr->last = NIL; 170 table = ptr; 171 } 172 173 /* 174 * Generate a unique non-zero sequence number 175 */ 176 int 177 new_id(void) 178 { 179 static int current_id = 0; 180 181 current_id = (current_id + 1) % MAX_ID; 182 /* 0 is reserved, helps to pick up bugs */ 183 if (current_id == 0) 184 current_id = 1; 185 return (current_id); 186 } 187 188 /* 189 * Delete the invitation with id 'id_num' 190 */ 191 int 192 delete_invite(u_int32_t id_num) 193 { 194 TABLE_ENTRY *ptr; 195 196 if (debug) 197 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 198 for (ptr = table; ptr != NIL; ptr = ptr->next) { 199 if (ptr->request.id_num == id_num) 200 break; 201 if (debug) 202 print_request("", &ptr->request); 203 } 204 if (ptr != NIL) { 205 delete(ptr); 206 return (SUCCESS); 207 } 208 return (NOT_HERE); 209 } 210 211 /* 212 * Classic delete from a double-linked list 213 */ 214 static void 215 delete(TABLE_ENTRY *ptr) 216 { 217 218 if (debug) 219 print_request("delete", &ptr->request); 220 if (table == ptr) 221 table = ptr->next; 222 else if (ptr->last != NIL) 223 ptr->last->next = ptr->next; 224 if (ptr->next != NIL) 225 ptr->next->last = ptr->last; 226 free((char *)ptr); 227 } 228