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
|
/*
* kdc/replay.c
*
* Copyright 1991 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* Replay lookaside cache for the KDC, to avoid extra work.
*
*/
#include "k5-int.h"
#include "kdc_util.h"
#include "extern.h"
#ifndef NOCACHE
typedef struct _krb5_kdc_replay_ent {
struct _krb5_kdc_replay_ent *next;
int num_hits;
krb5_int32 timein;
time_t db_age;
krb5_data *req_packet;
krb5_data *reply_packet;
krb5_address *addr; /* XXX should these not be pointers? */
} krb5_kdc_replay_ent;
static krb5_kdc_replay_ent root_ptr = {0};
static int hits = 0;
static int calls = 0;
static int max_hits_per_entry = 0;
static int num_entries = 0;
#define STALE_TIME 2*60 /* two minutes */
#define STALE(ptr) ((abs((ptr)->timein - timenow) >= STALE_TIME) || \
((ptr)->db_age != db_age))
#define MATCH(ptr) (((ptr)->req_packet->length == inpkt->length) && \
!memcmp((ptr)->req_packet->data, inpkt->data, \
inpkt->length) && \
((ptr)->addr->length == from->address->length) && \
!memcmp((ptr)->addr->contents, \
from->address->contents, \
from->address->length)&& \
((ptr)->db_age == db_age))
/* XXX
Todo: quench the size of the queue...
*/
/* return TRUE if outpkt is filled in with a packet to reply with,
FALSE if the caller should do the work */
krb5_boolean
kdc_check_lookaside(inpkt, from, outpkt)
register krb5_data *inpkt;
register krb5_fulladdr *from;
register krb5_data **outpkt;
{
krb5_int32 timenow;
register krb5_kdc_replay_ent *eptr, *last, *hold;
time_t db_age;
if (krb5_timeofday(kdc_context, &timenow) ||
krb5_db_get_age(kdc_context, 0, &db_age))
return FALSE;
calls++;
/* search for a replay entry in the queue, possibly removing
stale entries while we're here */
if (root_ptr.next) {
for (last = &root_ptr, eptr = root_ptr.next;
eptr;
eptr = eptr->next) {
if (MATCH(eptr)) {
eptr->num_hits++;
hits++;
if (krb5_copy_data(kdc_context, eptr->reply_packet, outpkt))
return FALSE;
else
return TRUE;
/* return here, don't bother flushing even if it is stale.
if we just matched, we may get another retransmit... */
}
if (STALE(eptr)) {
/* flush it and collect stats */
max_hits_per_entry = max(max_hits_per_entry, eptr->num_hits);
krb5_free_data(kdc_context, eptr->req_packet);
krb5_free_data(kdc_context, eptr->reply_packet);
krb5_free_address(kdc_context, eptr->addr);
hold = eptr;
last->next = eptr->next;
eptr = last;
free(hold);
} else {
/* this isn't it, just move along */
last = eptr;
}
}
}
return FALSE;
}
/* insert a request & reply into the lookaside queue. assumes it's not
already there, and can fail softly due to other weird errors. */
void
kdc_insert_lookaside(inpkt, from, outpkt)
register krb5_data *inpkt;
register krb5_fulladdr *from;
register krb5_data *outpkt;
{
register krb5_kdc_replay_ent *eptr;
krb5_int32 timenow;
time_t db_age;
if (krb5_timeofday(kdc_context, &timenow) ||
krb5_db_get_age(kdc_context, 0, &db_age))
return;
/* this is a new entry */
eptr = (krb5_kdc_replay_ent *)calloc(1, sizeof(*eptr));
if (!eptr)
return;
eptr->timein = timenow;
eptr->db_age = db_age;
/*
* This is going to hurt a lot malloc()-wise due to the need to
* allocate memory for the krb5_data and krb5_address elements.
* ARGH!
*/
if (krb5_copy_data(kdc_context, inpkt, &eptr->req_packet)) {
free(eptr);
return;
}
if (krb5_copy_data(kdc_context, outpkt, &eptr->reply_packet)) {
krb5_free_data(kdc_context, eptr->req_packet);
free(eptr);
return;
}
if (krb5_copy_addr(kdc_context, from->address, &eptr->addr)) {
krb5_free_data(kdc_context, eptr->req_packet);
krb5_free_data(kdc_context, eptr->reply_packet);
free(eptr);
return;
}
eptr->next = root_ptr.next;
root_ptr.next = eptr;
num_entries++;
return;
}
#endif /* NOCACHE */
|