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