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 * 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 * 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 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 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 196 delete_invite(u_int32_t id_num) 197 { 198 TABLE_ENTRY *ptr; 199 200 ptr = table; 201 if (debug) 202 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 203 for (ptr = table; ptr != NIL; ptr = ptr->next) { 204 if (ptr->request.id_num == id_num) 205 break; 206 if (debug) 207 print_request("", &ptr->request); 208 } 209 if (ptr != NIL) { 210 delete(ptr); 211 return (SUCCESS); 212 } 213 return (NOT_HERE); 214 } 215 216 /* 217 * Classic delete from a double-linked list 218 */ 219 static void 220 delete(TABLE_ENTRY *ptr) 221 { 222 223 if (debug) 224 print_request("delete", &ptr->request); 225 if (table == ptr) 226 table = ptr->next; 227 else if (ptr->last != NIL) 228 ptr->last->next = ptr->next; 229 if (ptr->next != NIL) 230 ptr->next->last = ptr->last; 231 free((char *)ptr); 232 } 233