Imported from /home/lorry/working-area/delta_tcp-wrappers/tcp_wrappers_7.6.tar.gz.HEADtcp_wrappers_7.6master

1 files changed, 136 insertions, 0 deletions

diff --git a/eval.c b/eval.c
new file mode 100644
index 0000000..d68358f
--- /dev/null
+++ b/eval.c
@@ -0,0 +1,136 @@
+ /*
+  * Routines for controlled evaluation of host names, user names, and so on.
+  * They are, in fact, wrappers around the functions that are specific for
+  * the sockets or TLI programming interfaces. The request_info and host_info
+  * structures are used for result cacheing.
+  * 
+  * These routines allows us to postpone expensive operations until their
+  * results are really needed. Examples are hostname lookups and double
+  * checks, or username lookups. Information that cannot be retrieved is
+  * given the value "unknown" ("paranoid" in case of hostname problems).
+  * 
+  * When ALWAYS_HOSTNAME is off, hostname lookup is done only when required by
+  * tcpd paranoid mode, by access control patterns, or by %letter expansions.
+  * 
+  * When ALWAYS_RFC931 mode is off, user lookup is done only when required by
+  * access control patterns or %letter expansions.
+  * 
+  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
+  */
+
+#ifndef lint
+static char sccsid[] = "@(#) eval.c 1.3 95/01/30 19:51:45";
+#endif
+
+/* System libraries. */
+
+#include <stdio.h>
+#include <string.h>
+
+/* Local stuff. */
+
+#include "tcpd.h"
+
+ /*
+  * When a string has the value STRING_UNKNOWN, it means: don't bother, I
+  * tried to look up the data but it was unavailable for some reason. When a
+  * host name has the value STRING_PARANOID it means there was a name/address
+  * conflict.
+  */
+char    unknown[] = STRING_UNKNOWN;
+char    paranoid[] = STRING_PARANOID;
+
+/* eval_user - look up user name */
+
+char   *eval_user(request)
+struct request_info *request;
+{
+    if (request->user[0] == 0) {
+	strcpy(request->user, unknown);
+	if (request->sink == 0 && request->client->sin && request->server->sin)
+	    rfc931(request->client->sin, request->server->sin, request->user);
+    }
+    return (request->user);
+}
+
+/* eval_hostaddr - look up printable address */
+
+char   *eval_hostaddr(host)
+struct host_info *host;
+{
+    if (host->addr[0] == 0) {
+	strcpy(host->addr, unknown);
+	if (host->request->hostaddr != 0)
+	    host->request->hostaddr(host);
+    }
+    return (host->addr);
+}
+
+/* eval_hostname - look up host name */
+
+char   *eval_hostname(host)
+struct host_info *host;
+{
+    if (host->name[0] == 0) {
+	strcpy(host->name, unknown);
+	if (host->request->hostname != 0)
+	    host->request->hostname(host);
+    }
+    return (host->name);
+}
+
+/* eval_hostinfo - return string with host name (preferred) or address */
+
+char   *eval_hostinfo(host)
+struct host_info *host;
+{
+    char   *hostname;
+
+#ifndef ALWAYS_HOSTNAME				/* no implicit host lookups */
+    if (host->name[0] == 0)
+	return (eval_hostaddr(host));
+#endif
+    hostname = eval_hostname(host);
+    if (HOSTNAME_KNOWN(hostname)) {
+	return (host->name);
+    } else {
+	return (eval_hostaddr(host));
+    }
+}
+
+/* eval_client - return string with as much about the client as we know */
+
+char   *eval_client(request)
+struct request_info *request;
+{
+    static char both[2 * STRING_LENGTH];
+    char   *hostinfo = eval_hostinfo(request->client);
+
+#ifndef ALWAYS_RFC931				/* no implicit user lookups */
+    if (request->user[0] == 0)
+	return (hostinfo);
+#endif
+    if (STR_NE(eval_user(request), unknown)) {
+	sprintf(both, "%s@%s", request->user, hostinfo);
+	return (both);
+    } else {
+	return (hostinfo);
+    }
+}
+
+/* eval_server - return string with as much about the server as we know */
+
+char   *eval_server(request)
+struct request_info *request;
+{
+    static char both[2 * STRING_LENGTH];
+    char   *host = eval_hostinfo(request->server);
+    char   *daemon = eval_daemon(request);
+
+    if (STR_NE(host, unknown)) {
+	sprintf(both, "%s@%s", daemon, host);
+	return (both);
+    } else {
+	return (daemon);
+    }
+}