/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Routines to handle insertion, deletion, etc on the table * of requests kept by the daemon. Nothing fancy here, linear * search on a double-linked list. A time is kept with each * entry so that overly old invitations can be eliminated. * * Consider this a mis-guided attempt at modularity */ #include <sys/param.h> #include <sys/time.h> #include <sys/socket.h> #include <netinet/in.h> #include <protocols/talkd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <syslog.h> #include <unistd.h> #include "extern.h" #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ #define NIL ((TABLE_ENTRY *)0) static struct timespec ts; typedef struct table_entry TABLE_ENTRY; struct table_entry { CTL_MSG request; long time; TABLE_ENTRY *next; TABLE_ENTRY *last; }; static void delete(TABLE_ENTRY *); static TABLE_ENTRY *table = NIL; /* * Look in the table for an invitation that matches the current * request looking for an invitation */ CTL_MSG * find_match(CTL_MSG *request) { TABLE_ENTRY *ptr, *next; time_t current_time; clock_gettime(CLOCK_MONOTONIC_FAST, &ts); current_time = ts.tv_sec; if (debug) print_request("find_match", request); for (ptr = table; ptr != NIL; ptr = next) { next = ptr->next; if ((ptr->time - current_time) > MAX_LIFE) { /* the entry is too old */ if (debug) print_request("deleting expired entry", &ptr->request); delete(ptr); continue; } if (debug) print_request("", &ptr->request); if (strcmp(request->l_name, ptr->request.r_name) == 0 && strcmp(request->r_name, ptr->request.l_name) == 0 && ptr->request.type == LEAVE_INVITE) return (&ptr->request); } return ((CTL_MSG *)0); } /* * Look for an identical request, as opposed to a complimentary * one as find_match does */ CTL_MSG * find_request(CTL_MSG *request) { TABLE_ENTRY *ptr, *next; time_t current_time; clock_gettime(CLOCK_MONOTONIC_FAST, &ts); current_time = ts.tv_sec; /* * See if this is a repeated message, and check for * out of date entries in the table while we are it. */ if (debug) print_request("find_request", request); for (ptr = table; ptr != NIL; ptr = next) { next = ptr->next; if ((ptr->time - current_time) > MAX_LIFE) { /* the entry is too old */ if (debug) print_request("deleting expired entry", &ptr->request); delete(ptr); continue; } if (debug) print_request("", &ptr->request); if (strcmp(request->r_name, ptr->request.r_name) == 0 && strcmp(request->l_name, ptr->request.l_name) == 0 && request->type == ptr->request.type && request->pid == ptr->request.pid) { /* update the time if we 'touch' it */ ptr->time = current_time; return (&ptr->request); } } return ((CTL_MSG *)0); } void insert_table(CTL_MSG *request, CTL_RESPONSE *response) { TABLE_ENTRY *ptr; time_t current_time; clock_gettime(CLOCK_MONOTONIC_FAST, &ts); current_time = ts.tv_sec; request->id_num = new_id(); response->id_num = htonl(request->id_num); /* insert a new entry into the top of the list */ ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); if (ptr == NIL) { syslog(LOG_ERR, "insert_table: Out of memory"); _exit(1); } ptr->time = current_time; ptr->request = *request; ptr->next = table; if (ptr->next != NIL) ptr->next->last = ptr; ptr->last = NIL; table = ptr; } /* * Generate a unique non-zero sequence number */ int new_id(void) { static int current_id = 0; current_id = (current_id + 1) % MAX_ID; /* 0 is reserved, helps to pick up bugs */ if (current_id == 0) current_id = 1; return (current_id); } /* * Delete the invitation with id 'id_num' */ int delete_invite(u_int32_t id_num) { TABLE_ENTRY *ptr; if (debug) syslog(LOG_DEBUG, "delete_invite(%d)", id_num); for (ptr = table; ptr != NIL; ptr = ptr->next) { if (ptr->request.id_num == id_num) break; if (debug) print_request("", &ptr->request); } if (ptr != NIL) { delete(ptr); return (SUCCESS); } return (NOT_HERE); } /* * Classic delete from a double-linked list */ static void delete(TABLE_ENTRY *ptr) { if (debug) print_request("delete", &ptr->request); if (table == ptr) table = ptr->next; else if (ptr->last != NIL) ptr->last->next = ptr->next; if (ptr->next != NIL) ptr->next->last = ptr->last; free((char *)ptr); }