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 /* System libraries. */ 22 23 #include <stdio.h> 24 #include <string.h> 25 26 /* Local stuff. */ 27 28 #include "tcpd.h" 29 30 /* 31 * When a string has the value STRING_UNKNOWN, it means: don't bother, I 32 * tried to look up the data but it was unavailable for some reason. When a 33 * host name has the value STRING_PARANOID it means there was a name/address 34 * conflict. 35 */ 36 char unknown[] = STRING_UNKNOWN; 37 char paranoid[] = STRING_PARANOID; 38 39 /* eval_user - look up user name */ 40 41 char *eval_user(request) 42 struct request_info *request; 43 { 44 if (request->user[0] == 0) { 45 strcpy(request->user, unknown); 46 if (request->sink == 0 && request->client->sin && request->server->sin) 47 rfc931(request->client->sin, request->server->sin, request->user); 48 } 49 return (request->user); 50 } 51 52 /* eval_hostaddr - look up printable address */ 53 54 char *eval_hostaddr(host) 55 struct host_info *host; 56 { 57 if (host->addr[0] == 0) { 58 strcpy(host->addr, unknown); 59 if (host->request->hostaddr != 0) 60 host->request->hostaddr(host); 61 } 62 return (host->addr); 63 } 64 65 /* eval_hostname - look up host name */ 66 67 char *eval_hostname(host) 68 struct host_info *host; 69 { 70 if (host->name[0] == 0) { 71 strcpy(host->name, unknown); 72 if (host->request->hostname != 0) 73 host->request->hostname(host); 74 } 75 return (host->name); 76 } 77 78 /* eval_hostinfo - return string with host name (preferred) or address */ 79 80 char *eval_hostinfo(host) 81 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(request) 100 struct request_info *request; 101 { 102 static char both[2 * STRING_LENGTH]; 103 char *hostinfo = eval_hostinfo(request->client); 104 105 #ifndef ALWAYS_RFC931 /* no implicit user lookups */ 106 if (request->user[0] == 0) 107 return (hostinfo); 108 #endif 109 if (STR_NE(eval_user(request), unknown)) { 110 sprintf(both, "%s@%s", request->user, hostinfo); 111 return (both); 112 } else { 113 return (hostinfo); 114 } 115 } 116 117 /* eval_server - return string with as much about the server as we know */ 118 119 char *eval_server(request) 120 struct request_info *request; 121 { 122 static char both[2 * STRING_LENGTH]; 123 char *host = eval_hostinfo(request->server); 124 char *daemon = eval_daemon(request); 125 126 if (STR_NE(host, unknown)) { 127 sprintf(both, "%s@%s", daemon, host); 128 return (both); 129 } else { 130 return (daemon); 131 } 132 } 133