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/*
* 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;
byte *end = buf + size - 8;
int sp = 1;
int l, isset;
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;
}
int
as_path_get_first(struct adata *path)
{
int res = -1;
u8 *p = path->data;
u8 *q = p+path->length;
int len;
while (p<q)
{
switch (*p++)
{
case AS_PATH_SET:
if (len = *p++)
res = get_u16(p);
p += 2*len;
break;
case AS_PATH_SEQUENCE:
if (len = *p++)
res = get_u16(p+2*(len-1));
p += 2*len;
break;
default: bug("as_path_get_first: 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;
}
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