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 timespec ts; 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, *next; 86 time_t current_time; 87 88 clock_gettime(CLOCK_MONOTONIC_FAST, &ts); 89 current_time = ts.tv_sec; 90 if (debug) 91 print_request("find_match", request); 92 for (ptr = table; ptr != NIL; ptr = next) { 93 next = ptr->next; 94 if ((ptr->time - current_time) > MAX_LIFE) { 95 /* the entry is too old */ 96 if (debug) 97 print_request("deleting expired entry", 98 &ptr->request); 99 delete(ptr); 100 continue; 101 } 102 if (debug) 103 print_request("", &ptr->request); 104 if (strcmp(request->l_name, ptr->request.r_name) == 0 && 105 strcmp(request->r_name, ptr->request.l_name) == 0 && 106 ptr->request.type == LEAVE_INVITE) 107 return (&ptr->request); 108 } 109 return ((CTL_MSG *)0); 110 } 111 112 /* 113 * Look for an identical request, as opposed to a complimentary 114 * one as find_match does 115 */ 116 CTL_MSG * 117 find_request(CTL_MSG *request) 118 { 119 TABLE_ENTRY *ptr, *next; 120 time_t current_time; 121 122 clock_gettime(CLOCK_MONOTONIC_FAST, &ts); 123 current_time = ts.tv_sec; 124 /* 125 * See if this is a repeated message, and check for 126 * out of date entries in the table while we are it. 127 */ 128 if (debug) 129 print_request("find_request", request); 130 for (ptr = table; ptr != NIL; ptr = next) { 131 next = ptr->next; 132 if ((ptr->time - current_time) > MAX_LIFE) { 133 /* the entry is too old */ 134 if (debug) 135 print_request("deleting expired entry", 136 &ptr->request); 137 delete(ptr); 138 continue; 139 } 140 if (debug) 141 print_request("", &ptr->request); 142 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 143 strcmp(request->l_name, ptr->request.l_name) == 0 && 144 request->type == ptr->request.type && 145 request->pid == ptr->request.pid) { 146 /* update the time if we 'touch' it */ 147 ptr->time = current_time; 148 return (&ptr->request); 149 } 150 } 151 return ((CTL_MSG *)0); 152 } 153 154 void 155 insert_table(CTL_MSG *request, CTL_RESPONSE *response) 156 { 157 TABLE_ENTRY *ptr; 158 time_t current_time; 159 160 clock_gettime(CLOCK_MONOTONIC_FAST, &ts); 161 current_time = ts.tv_sec; 162 request->id_num = new_id(); 163 response->id_num = htonl(request->id_num); 164 /* insert a new entry into the top of the list */ 165 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 166 if (ptr == NIL) { 167 syslog(LOG_ERR, "insert_table: Out of memory"); 168 _exit(1); 169 } 170 ptr->time = current_time; 171 ptr->request = *request; 172 ptr->next = table; 173 if (ptr->next != NIL) 174 ptr->next->last = ptr; 175 ptr->last = NIL; 176 table = ptr; 177 } 178 179 /* 180 * Generate a unique non-zero sequence number 181 */ 182 int 183 new_id(void) 184 { 185 static int current_id = 0; 186 187 current_id = (current_id + 1) % MAX_ID; 188 /* 0 is reserved, helps to pick up bugs */ 189 if (current_id == 0) 190 current_id = 1; 191 return (current_id); 192 } 193 194 /* 195 * Delete the invitation with id 'id_num' 196 */ 197 int 198 delete_invite(u_int32_t id_num) 199 { 200 TABLE_ENTRY *ptr; 201 202 if (debug) 203 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 204 for (ptr = table; ptr != NIL; ptr = ptr->next) { 205 if (ptr->request.id_num == id_num) 206 break; 207 if (debug) 208 print_request("", &ptr->request); 209 } 210 if (ptr != NIL) { 211 delete(ptr); 212 return (SUCCESS); 213 } 214 return (NOT_HERE); 215 } 216 217 /* 218 * Classic delete from a double-linked list 219 */ 220 static void 221 delete(TABLE_ENTRY *ptr) 222 { 223 224 if (debug) 225 print_request("delete", &ptr->request); 226 if (table == ptr) 227 table = ptr->next; 228 else if (ptr->last != NIL) 229 ptr->last->next = ptr->next; 230 if (ptr->next != NIL) 231 ptr->next->last = ptr->last; 232 free((char *)ptr); 233 } 234