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
22static 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  */
40char    unknown[] = STRING_UNKNOWN;
41char    paranoid[] = STRING_PARANOID;
42
43/* eval_user - look up user name */
44
45char   *eval_user(request)
46struct 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
58char   *eval_hostaddr(host)
59struct 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
71char   *eval_hostname(host)
72struct 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
84char   *eval_hostinfo(host)
85struct 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
103char   *eval_client(request)
104struct 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
123char   *eval_server(request)
124struct 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