summaryrefslogtreecommitdiff
path: root/source3/libsmb/conncache.c
blob: 790ad47fa5df14417835844f515131ef019d10ce (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
/* 
   Unix SMB/CIFS implementation.

   Winbind daemon connection manager

   Copyright (C) Tim Potter 		2001
   Copyright (C) Andrew Bartlett 	2002
   Copyright (C) Gerald (Jerry) Carter 	2003
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/


#include "includes.h"

#define CONNCACHE_ADDR		1
#define CONNCACHE_NAME		2

/* cache entry contains either a server name **or** and IP address as 
   the key.  This means that a server could have two entries (one for each key) */
   
struct failed_connection_cache {
	fstring 	domain_name;
	fstring 	controller;
	time_t 		lookup_time;
	NTSTATUS 	nt_status;
	struct failed_connection_cache *prev, *next;
};

static struct failed_connection_cache *failed_connection_cache;

/**********************************************************************
 Check for a previously failed connection.
 failed_cache_timeout is an a absolute number of seconds after which
 we should time this out. If failed_cache_timeout == 0 then time out
 immediately. If failed_cache_timeout == -1 then never time out.
**********************************************************************/

NTSTATUS check_negative_conn_cache_timeout( const char *domain, const char *server, unsigned int failed_cache_timeout )
{
	struct failed_connection_cache *fcc;
	NTSTATUS result = NT_STATUS_UNSUCCESSFUL;
	
	/* can't check if we don't have strings */
	
	if ( !domain || !server )
		return NT_STATUS_OK;

	for (fcc = failed_connection_cache; fcc; fcc = fcc->next) {
	
		if (!(strequal(domain, fcc->domain_name) && strequal(server, fcc->controller))) {
			continue; /* no match; check the next entry */
		}
		
		/* we have a match so see if it is still current */
		if (failed_cache_timeout != (unsigned int)-1) {
			if (failed_cache_timeout == 0 ||
					(time(NULL) - fcc->lookup_time) > (time_t)failed_cache_timeout) {
				/* Cache entry has expired, delete it */

				DEBUG(10, ("check_negative_conn_cache: cache entry expired for %s, %s\n", 
					domain, server ));

				DLIST_REMOVE(failed_connection_cache, fcc);
				SAFE_FREE(fcc);

				return NT_STATUS_OK;
			}
		}

		/* The timeout hasn't expired yet so return false */

		DEBUG(10, ("check_negative_conn_cache: returning negative entry for %s, %s\n", 
			domain, server ));

		result = fcc->nt_status;
		return result;
	}

	/* end of function means no cache entry */	
	return NT_STATUS_OK;
}

NTSTATUS check_negative_conn_cache( const char *domain, const char *server)
{
	return check_negative_conn_cache_timeout(domain, server, FAILED_CONNECTION_CACHE_TIMEOUT);
}

/**********************************************************************
 Add an entry to the failed conneciton cache (aither a name of dotted 
 decimal IP
**********************************************************************/

void add_failed_connection_entry(const char *domain, const char *server, NTSTATUS result) 
{
	struct failed_connection_cache *fcc;

	SMB_ASSERT(!NT_STATUS_IS_OK(result));

	/* Check we already aren't in the cache.  We always have to have 
	   a domain, but maybe not a specific DC name. */

	for (fcc = failed_connection_cache; fcc; fcc = fcc->next) {			
		if ( strequal(fcc->domain_name, domain) && strequal(fcc->controller, server) ) {
			DEBUG(10, ("add_failed_connection_entry: domain %s (%s) already tried and failed\n",
				   domain, server ));
			/* Update the failed time. */
			fcc->lookup_time = time(NULL);
			return;
		}
	}

	/* Create negative lookup cache entry for this domain and controller */

	if ( !(fcc = SMB_MALLOC_P(struct failed_connection_cache)) ) {
		DEBUG(0, ("malloc failed in add_failed_connection_entry!\n"));
		return;
	}
	
	ZERO_STRUCTP(fcc);
	
	fstrcpy( fcc->domain_name, domain );
	fstrcpy( fcc->controller, server );
	fcc->lookup_time = time(NULL);
	fcc->nt_status = result;
	
	DEBUG(10,("add_failed_connection_entry: added domain %s (%s) to failed conn cache\n",
		domain, server ));
	
	DLIST_ADD(failed_connection_cache, fcc);
}

/****************************************************************************
****************************************************************************/
 
void flush_negative_conn_cache( void )
{
	struct failed_connection_cache *fcc;
	
	fcc = failed_connection_cache;

	while (fcc) {
		struct failed_connection_cache *fcc_next;

		fcc_next = fcc->next;
		DLIST_REMOVE(failed_connection_cache, fcc);
		free(fcc);

		fcc = fcc_next;
	}

}

/****************************************************************************
 Remove all negative entries for a domain. Used when going to online state in
 winbindd.
****************************************************************************/
 
void flush_negative_conn_cache_for_domain(const char *domain)
{
	struct failed_connection_cache *fcc;
	
	fcc = failed_connection_cache;

	while (fcc) {
		struct failed_connection_cache *fcc_next;

		fcc_next = fcc->next;

		if (strequal(fcc->domain_name, domain)) {
			DEBUG(10,("flush_negative_conn_cache_for_domain: removed server %s "
				" from failed cache for domain %s\n",
				fcc->controller, domain));
			DLIST_REMOVE(failed_connection_cache, fcc);
			free(fcc);
		}

		fcc = fcc_next;
	}
}