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(struct request_info *request) 46 { 47 if (request->user[0] == 0) { 48 strcpy(request->user, unknown); 49 if (request->sink == 0 && request->client->sin && request->server->sin) 50 rfc931(request->client->sin, request->server->sin, request->user); 51 } 52 return (request->user); 53 } 54 55 /* eval_hostaddr - look up printable address */ 56 57 char *eval_hostaddr(struct host_info *host) 58 { 59 if (host->addr[0] == 0) { 60 strcpy(host->addr, unknown); 61 if (host->request->hostaddr != 0) 62 host->request->hostaddr(host); 63 } 64 return (host->addr); 65 } 66 67 /* eval_hostname - look up host name */ 68 69 char *eval_hostname(struct host_info *host) 70 { 71 if (host->name[0] == 0) { 72 strcpy(host->name, unknown); 73 if (host->request->hostname != 0) 74 host->request->hostname(host); 75 } 76 return (host->name); 77 } 78 79 /* eval_hostinfo - return string with host name (preferred) or address */ 80 81 char *eval_hostinfo(struct host_info *host) 82 { 83 char *hostname; 84 85 #ifndef ALWAYS_HOSTNAME /* no implicit host lookups */ 86 if (host->name[0] == 0) 87 return (eval_hostaddr(host)); 88 #endif 89 hostname = eval_hostname(host); 90 if (HOSTNAME_KNOWN(hostname)) { 91 return (host->name); 92 } else { 93 return (eval_hostaddr(host)); 94 } 95 } 96 97 /* eval_client - return string with as much about the client as we know */ 98 99 char *eval_client(struct request_info *request) 100 { 101 static char both[2 * STRING_LENGTH]; 102 char *hostinfo = eval_hostinfo(request->client); 103 104 #ifndef ALWAYS_RFC931 /* no implicit user lookups */ 105 if (request->user[0] == 0) 106 return (hostinfo); 107 #endif 108 if (STR_NE(eval_user(request), unknown)) { 109 sprintf(both, "%s@%s", request->user, hostinfo); 110 return (both); 111 } else { 112 return (hostinfo); 113 } 114 } 115 116 /* eval_server - return string with as much about the server as we know */ 117 118 char *eval_server(struct request_info *request) 119 { 120 static char both[2 * STRING_LENGTH]; 121 char *host = eval_hostinfo(request->server); 122 char *daemon = eval_daemon(request); 123 124 if (STR_NE(host, unknown)) { 125 sprintf(both, "%s@%s", daemon, host); 126 return (both); 127 } else { 128 return (daemon); 129 } 130 } 131