1 /* 2 * Routines for controlled evaluation of host names, user names, and so on. 3 * They are, in fact, wrappers around the functions that are specific for 4 * the sockets or TLI programming interfaces. The request_info and host_info 5 * structures are used for result cacheing. 6 * 7 * These routines allows us to postpone expensive operations until their 8 * results are really needed. Examples are hostname lookups and double 9 * checks, or username lookups. Information that cannot be retrieved is 10 * given the value "unknown" ("paranoid" in case of hostname problems). 11 * 12 * When ALWAYS_HOSTNAME is off, hostname lookup is done only when required by 13 * tcpd paranoid mode, by access control patterns, or by %letter expansions. 14 * 15 * When ALWAYS_RFC931 mode is off, user lookup is done only when required by 16 * access control patterns or %letter expansions. 17 * 18 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. 19 */ 20 21 #ifndef lint 22 static char sccsid[] = "@(#) eval.c 1.3 95/01/30 19:51:45"; 23 #endif 24 25 /* System libraries. */ 26 27 #include <stdio.h> 28 #include <string.h> 29 30 /* Local stuff. */ 31 32 #include "tcpd.h" 33 34 /* 35 * When a string has the value STRING_UNKNOWN, it means: don't bother, I 36 * tried to look up the data but it was unavailable for some reason. When a 37 * host name has the value STRING_PARANOID it means there was a name/address 38 * conflict. 39 */ 40 char unknown[] = STRING_UNKNOWN; 41 char paranoid[] = STRING_PARANOID; 42 43 /* eval_user - look up user name */ 44 45 char *eval_user(request) 46 struct request_info *request; 47 { 48 if (request->user[0] == 0) { 49 strcpy(request->user, unknown); 50 if (request->sink == 0 && request->client->sin && request->server->sin) 51 rfc931(request->client->sin, request->server->sin, request->user); 52 } 53 return (request->user); 54 } 55 56 /* eval_hostaddr - look up printable address */ 57 58 char *eval_hostaddr(host) 59 struct host_info *host; 60 { 61 if (host->addr[0] == 0) { 62 strcpy(host->addr, unknown); 63 if (host->request->hostaddr != 0) 64 host->request->hostaddr(host); 65 } 66 return (host->addr); 67 } 68 69 /* eval_hostname - look up host name */ 70 71 char *eval_hostname(host) 72 struct host_info *host; 73 { 74 if (host->name[0] == 0) { 75 strcpy(host->name, unknown); 76 if (host->request->hostname != 0) 77 host->request->hostname(host); 78 } 79 return (host->name); 80 } 81 82 /* eval_hostinfo - return string with host name (preferred) or address */ 83 84 char *eval_hostinfo(host) 85 struct host_info *host; 86 { 87 char *hostname; 88 89 #ifndef ALWAYS_HOSTNAME /* no implicit host lookups */ 90 if (host->name[0] == 0) 91 return (eval_hostaddr(host)); 92 #endif 93 hostname = eval_hostname(host); 94 if (HOSTNAME_KNOWN(hostname)) { 95 return (host->name); 96 } else { 97 return (eval_hostaddr(host)); 98 } 99 } 100 101 /* eval_client - return string with as much about the client as we know */ 102 103 char *eval_client(request) 104 struct request_info *request; 105 { 106 static char both[2 * STRING_LENGTH]; 107 char *hostinfo = eval_hostinfo(request->client); 108 109 #ifndef ALWAYS_RFC931 /* no implicit user lookups */ 110 if (request->user[0] == 0) 111 return (hostinfo); 112 #endif 113 if (STR_NE(eval_user(request), unknown)) { 114 sprintf(both, "%s@%s", request->user, hostinfo); 115 return (both); 116 } else { 117 return (hostinfo); 118 } 119 } 120 121 /* eval_server - return string with as much about the server as we know */ 122 123 char *eval_server(request) 124 struct request_info *request; 125 { 126 static char both[2 * STRING_LENGTH]; 127 char *host = eval_hostinfo(request->server); 128 char *daemon = eval_daemon(request); 129 130 if (STR_NE(host, unknown)) { 131 sprintf(both, "%s@%s", daemon, host); 132 return (both); 133 } else { 134 return (daemon); 135 } 136 } 137