1/*
2 *  This file is free software: you may copy, redistribute and/or modify it
3 *  under the terms of the GNU General Public License as published by the
4 *  Free Software Foundation, either version 2 of the License, or (at your
5 *  option) any later version.
6 *
7 *  This file is distributed in the hope that it will be useful, but
8 *  WITHOUT ANY WARRANTY; without even the implied warranty of
9 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
10 *  General Public License for more details.
11 *
12 *  You should have received a copy of the GNU General Public License
13 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
14 *
15 * This file incorporates work covered by the following copyright and
16 * permission notice:
17 *
18Copyright (c) 2007, 2008 by Juliusz Chroboczek
19
20Permission is hereby granted, free of charge, to any person obtaining a copy
21of this software and associated documentation files (the "Software"), to deal
22in the Software without restriction, including without limitation the rights
23to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
24copies of the Software, and to permit persons to whom the Software is
25furnished to do so, subject to the following conditions:
26
27The above copyright notice and this permission notice shall be included in
28all copies or substantial portions of the Software.
29
30THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
31IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
32FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
33AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
34LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
35OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
36THE SOFTWARE.
37*/
38
39#include <stdlib.h>
40#include <stdio.h>
41#include <string.h>
42#include <sys/time.h>
43
44#include "babel_main.h"
45#include "babeld.h"
46#include "util.h"
47#include "source.h"
48#include "babel_interface.h"
49#include "route.h"
50
51struct source *srcs = NULL;
52
53struct source*
54find_source(const unsigned char *id, const unsigned char *p, unsigned char plen,
55            int create, unsigned short seqno)
56{
57    struct source *src;
58
59    for(src = srcs; src; src = src->next) {
60        /* This should really be a hash table.  For now, check the
61           last byte first. */
62        if(src->id[7] != id[7])
63            continue;
64        if(memcmp(src->id, id, 8) != 0)
65            continue;
66        if(src->plen != plen)
67            continue;
68        if(memcmp(src->prefix, p, 16) == 0)
69            return src;
70    }
71
72    if(!create)
73        return NULL;
74
75    src = malloc(sizeof(struct source));
76    if(src == NULL) {
77        zlog_err("malloc(source): %s", safe_strerror(errno));
78        return NULL;
79    }
80
81    memcpy(src->id, id, 8);
82    memcpy(src->prefix, p, 16);
83    src->plen = plen;
84    src->seqno = seqno;
85    src->metric = INFINITY;
86    src->time = babel_now.tv_sec;
87    src->route_count = 0;
88    src->next = srcs;
89    srcs = src;
90    return src;
91}
92
93struct source *
94retain_source(struct source *src)
95{
96    assert(src->route_count < 0xffff);
97    src->route_count++;
98    return src;
99}
100
101void
102release_source(struct source *src)
103{
104    assert(src->route_count > 0);
105    src->route_count--;
106}
107
108int
109flush_source(struct source *src)
110{
111    if(src->route_count > 0)
112        /* The source is in use by a route. */
113        return 0;
114
115    if(srcs == src) {
116        srcs = src->next;
117    } else {
118        struct source *previous = srcs;
119        while(previous->next != src)
120            previous = previous->next;
121        previous->next = src->next;
122    }
123
124    free(src);
125    return 1;
126}
127
128void
129update_source(struct source *src,
130              unsigned short seqno, unsigned short metric)
131{
132    if(metric >= INFINITY)
133        return;
134
135    /* If a source is expired, pretend that it doesn't exist and update
136       it unconditionally.  This makes ensures that old data will
137       eventually be overridden, and prevents us from getting stuck if
138       a router loses its sequence number. */
139    if(src->time < babel_now.tv_sec - SOURCE_GC_TIME ||
140       seqno_compare(src->seqno, seqno) < 0 ||
141       (src->seqno == seqno && src->metric > metric)) {
142        src->seqno = seqno;
143        src->metric = metric;
144    }
145    src->time = babel_now.tv_sec;
146}
147
148void
149expire_sources()
150{
151    struct source *src;
152
153    src = srcs;
154    while(src) {
155        if(src->time > babel_now.tv_sec)
156            /* clock stepped */
157            src->time = babel_now.tv_sec;
158        if(src->time < babel_now.tv_sec - SOURCE_GC_TIME) {
159            struct source *old = src;
160            src = src->next;
161            flush_source(old);
162            continue;
163        }
164        src = src->next;
165    }
166}
167
168void
169check_sources_released(void)
170{
171    struct source *src;
172
173    for(src = srcs; src; src = src->next) {
174        if(src->route_count != 0)
175            fprintf(stderr, "Warning: source %s %s has refcount %d.\n",
176                    format_eui64(src->id),
177                    format_prefix(src->prefix, src->plen),
178                    (int)src->route_count);
179    }
180}
181