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
|
/*
* BIRD -- Path Operations
*
* (c) 2000 Martin Mares <mj@ucw.cz>
* (c) 2000 Pavel Machek <pavel@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/attrs.h"
#include "lib/resource.h"
#include "lib/unaligned.h"
#include "lib/string.h"
struct adata *
as_path_prepend(struct linpool *pool, struct adata *olda, int as)
{
struct adata *newa;
if (olda->length && olda->data[0] == AS_PATH_SEQUENCE &&
olda->data[1] < 255) /* Starting with sequence => just prepend the AS number */
{
newa = lp_alloc(pool, sizeof(struct adata) + olda->length + 2);
newa->length = olda->length + 2;
newa->data[0] = 2;
newa->data[1] = olda->data[1] + 1;
memcpy(newa->data+4, olda->data+2, olda->length-2);
}
else /* Create new path segment */
{
newa = lp_alloc(pool, sizeof(struct adata) + olda->length + 4);
newa->length = olda->length + 4;
newa->data[0] = 2;
newa->data[1] = 1;
memcpy(newa->data+4, olda->data, olda->length);
}
put_u16(newa->data+2, as);
return newa;
}
void
as_path_format(struct adata *path, byte *buf, unsigned int size)
{
byte *p = path->data;
byte *e = p + path->length - 8;
byte *end = buf + size;
int sp = 1;
int l, type, isset, as;
while (p < e)
{
if (buf > end)
{
strcpy(buf, " ...");
return;
}
isset = (*p++ == AS_PATH_SET);
l = *p++;
if (isset)
{
if (!sp)
*buf++ = ' ';
*buf++ = '{';
sp = 0;
}
while (l-- && buf <= end)
{
if (!sp)
*buf++ = ' ';
buf += bsprintf(buf, "%d", get_u16(p));
p += 2;
sp = 0;
}
if (isset)
{
*buf++ = ' ';
*buf++ = '}';
sp = 0;
}
}
*buf = 0;
}
int
as_path_getlen(struct adata *path)
{
int res = 0;
u8 *p = path->data;
u8 *q = p+path->length;
int len;
while (p<q)
{
switch (*p++)
{
case AS_PATH_SET: len = *p++; res++; p += 2*len; break;
case AS_PATH_SEQUENCE: len = *p++; res+=len; p += 2*len; break;
default: bug("as_path_getlen: Invalid path segment");
}
}
return res;
}
#define MASK_PLUS do { mask = mask->next; if (!mask) return next == q; \
asterisk = (mask->val == PM_ANY); \
if (asterisk) { mask = mask->next; if (!mask) { return 1; } } \
} while(0)
int
as_path_match(struct adata *path, struct f_path_mask *mask)
{
int i;
int asterisk = 0;
u8 *p = path->data;
u8 *q = p+path->length;
int len;
u8 *next;
asterisk = (mask->val == PM_ANY);
if (asterisk)
{ mask = mask->next; if (!mask) return 1; }
while (p<q) {
switch (*p++) {
case AS_PATH_SET:
len = *p++;
{
u8 *p_save = p;
next = p_save + 2*len;
retry:
p = p_save;
for (i=0; i<len; i++) {
if (asterisk && (get_u16(p) == mask->val)) {
MASK_PLUS;
goto retry;
}
if (!asterisk && (get_u16(p) == mask->val)) {
p = next;
MASK_PLUS;
goto okay;
}
p+=2;
}
if (!asterisk)
return 0;
okay:
}
break;
case AS_PATH_SEQUENCE:
len = *p++;
for (i=0; i<len; i++) {
next = p+2;
if (asterisk && (get_u16(p) == mask->val))
MASK_PLUS;
else if (!asterisk) {
if (get_u16(p) != mask->val)
return 0;
MASK_PLUS;
}
p+=2;
}
break;
default:
bug("as_path_match: Invalid path component");
}
}
return 0;
}
|
