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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] == 2 && 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 1: len = *p++; res++; p += 2*len; break;
case 2: len = *p++; res+=len; p += 2*len; break;
default: bug("This should not be in path");
}
}
return res;
}
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