summaryrefslogtreecommitdiff
path: root/nest/a-path.c
diff options
context:
space:
mode:
Diffstat (limited to 'nest/a-path.c')
-rw-r--r--nest/a-path.c936
1 files changed, 0 insertions, 936 deletions
diff --git a/nest/a-path.c b/nest/a-path.c
deleted file mode 100644
index 6bb18285..00000000
--- a/nest/a-path.c
+++ /dev/null
@@ -1,936 +0,0 @@
-/*
- * 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"
-#include "filter/data.h"
-
-// static inline void put_as(byte *data, u32 as) { put_u32(data, as); }
-// static inline u32 get_as(byte *data) { return get_u32(data); }
-
-#define put_as put_u32
-#define get_as get_u32
-#define BS 4 /* Default block size of ASN (autonomous system number) */
-
-#define BAD(DSC, VAL) ({ err_dsc = DSC; err_val = VAL; goto bad; })
-
-int
-as_path_valid(byte *data, uint len, int bs, int sets, int confed, char *err, uint elen)
-{
- byte *pos = data;
- char *err_dsc = NULL;
- uint err_val = 0;
-
- while (len)
- {
- if (len < 2)
- BAD("segment framing error", 0);
-
- /* Process one AS path segment */
- uint type = pos[0];
- uint slen = 2 + bs * pos[1];
-
- if (len < slen)
- BAD("segment framing error", len);
-
- switch (type)
- {
- case AS_PATH_SET:
- if (!sets)
- BAD("AS_SET segment", type);
- break;
-
- case AS_PATH_SEQUENCE:
- break;
-
- case AS_PATH_CONFED_SEQUENCE:
- if (!confed)
- BAD("AS_CONFED_SEQUENCE segment", type);
- break;
-
- case AS_PATH_CONFED_SET:
- if (!sets || !confed)
- BAD("AS_CONFED_SET segment", type);
- break;
-
- default:
- BAD("unknown segment", type);
- }
-
- if (pos[1] == 0)
- BAD("zero-length segment", type);
-
- pos += slen;
- len -= slen;
- }
-
- return 1;
-
-bad:
- if (err)
- if (bsnprintf(err, elen, "%s (%u) at %d", err_dsc, err_val, (int) (pos - data)) < 0)
- err[0] = 0;
-
- return 0;
-}
-
-int
-as_path_16to32(byte *dst, const byte *src, uint len)
-{
- byte *dst0 = dst;
- const byte *end = src + len;
- uint i, n;
-
- while (src < end)
- {
- n = src[1];
- *dst++ = *src++;
- *dst++ = *src++;
-
- for (i = 0; i < n; i++)
- {
- put_u32(dst, get_u16(src));
- src += 2;
- dst += 4;
- }
- }
-
- return dst - dst0;
-}
-
-int
-as_path_32to16(byte *dst, const byte *src, uint len)
-{
- byte *dst0 = dst;
- const byte *end = src + len;
- uint i, n;
-
- while (src < end)
- {
- n = src[1];
- *dst++ = *src++;
- *dst++ = *src++;
-
- for (i = 0; i < n; i++)
- {
- put_u16(dst, get_u32(src));
- src += 4;
- dst += 2;
- }
- }
-
- return dst - dst0;
-}
-
-int
-as_path_contains_as4(const struct adata *path)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
- uint i, n;
-
- while (pos < end)
- {
- n = pos[1];
- pos += 2;
-
- for (i = 0; i < n; i++)
- {
- if (get_as(pos) > 0xFFFF)
- return 1;
-
- pos += BS;
- }
- }
-
- return 0;
-}
-
-int
-as_path_contains_confed(const struct adata *path)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
-
- while (pos < end)
- {
- uint type = pos[0];
- uint slen = 2 + BS * pos[1];
-
- if ((type == AS_PATH_CONFED_SEQUENCE) ||
- (type == AS_PATH_CONFED_SET))
- return 1;
-
- pos += slen;
- }
-
- return 0;
-}
-
-struct adata *
-as_path_strip_confed(struct linpool *pool, const struct adata *path)
-{
- struct adata *res = lp_alloc_adata(pool, path->length);
- const byte *src = path->data;
- const byte *end = src + path->length;
- byte *dst = res->data;
-
- while (src < end)
- {
- uint type = src[0];
- uint slen = 2 + BS * src[1];
-
- /* Copy regular segments */
- if ((type == AS_PATH_SET) || (type == AS_PATH_SEQUENCE))
- {
- memcpy(dst, src, slen);
- dst += slen;
- }
-
- src += slen;
- }
-
- /* Fix the result length */
- res->length = dst - res->data;
-
- return res;
-}
-
-struct adata *
-as_path_prepend2(struct linpool *pool, const struct adata *op, int seq, u32 as)
-{
- struct adata *np;
- const byte *pos = op->data;
- uint len = op->length;
-
- if (len && (pos[0] == seq) && (pos[1] < 255))
- {
- /* Starting with matching segment => just prepend the AS number */
- np = lp_alloc_adata(pool, len + BS);
- np->data[0] = seq;
- np->data[1] = pos[1] + 1;
- put_as(np->data + 2, as);
-
- uint dlen = BS * pos[1];
- memcpy(np->data + 2 + BS, pos + 2, dlen);
- ADVANCE(pos, len, 2 + dlen);
- }
- else
- {
- /* Create a new path segment */
- np = lp_alloc_adata(pool, len + 2 + BS);
- np->data[0] = seq;
- np->data[1] = 1;
- put_as(np->data + 2, as);
- }
-
- if (len)
- {
- byte *dst = np->data + 2 + BS * np->data[1];
-
- memcpy(dst, pos, len);
- }
-
- return np;
-}
-
-
-struct adata *
-as_path_to_old(struct linpool *pool, const struct adata *path)
-{
- struct adata *res = lp_alloc_adata(pool, path->length);
- byte *pos = res->data;
- byte *end = pos + res->length;
- uint i, n;
- u32 as;
-
- /* Copy the whole path */
- memcpy(res->data, path->data, path->length);
-
- /* Replace 32-bit AS numbers with AS_TRANS */
- while (pos < end)
- {
- n = pos[1];
- pos += 2;
-
- for (i = 0; i < n; i++)
- {
- as = get_as(pos);
- if (as > 0xFFFF)
- put_as(pos, AS_TRANS);
-
- pos += BS;
- }
- }
-
- return res;
-}
-
-/*
- * Cut the path to the length @num, measured to the usual path metric. Note that
- * AS_CONFED_* segments have zero length and must be added if they are on edge.
- */
-struct adata *
-as_path_cut(struct linpool *pool, const struct adata *path, uint num)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
-
- while (pos < end)
- {
- uint t = pos[0];
- uint l = pos[1];
- uint n = 0;
-
- switch (t)
- {
- case AS_PATH_SET: n = 1; break;
- case AS_PATH_SEQUENCE: n = l; break;
- case AS_PATH_CONFED_SEQUENCE: n = 0; break;
- case AS_PATH_CONFED_SET: n = 0; break;
- default: bug("as_path_cut: Invalid path segment");
- }
-
- /* Cannot add whole segment, so try partial one and finish */
- if (num < n)
- {
- const byte *nend = pos;
- if (num)
- nend += 2 + BS * num;
-
- struct adata *res = lp_alloc_adata(pool, path->length);
- res->length = nend - (const byte *) path->data;
- memcpy(res->data, path->data, res->length);
-
- if (num)
- {
- byte *dpos = ((byte *) res->data) + (pos - (const byte *) path->data);
- dpos[1] = num;
- }
-
- return res;
- }
-
- num -= n;
- pos += 2 + BS * l;
- }
-
- struct adata *res = lp_alloc_adata(pool, path->length);
- res->length = path->length;
- memcpy(res->data, path->data, res->length);
- return res;
-}
-
-/*
- * Merge (concatenate) paths @p1 and @p2 and return the result.
- * In contrast to other as_path_* functions, @p1 and @p2 may be reused.
- */
-const struct adata *
-as_path_merge(struct linpool *pool, const struct adata *p1, const struct adata *p2)
-{
- if (p1->length == 0)
- return p2;
-
- if (p2->length == 0)
- return p1;
-
- struct adata *res = lp_alloc_adata(pool, p1->length + p2->length);
- memcpy(res->data, p1->data, p1->length);
- memcpy(res->data + p1->length, p2->data, p2->length);
-
- return res;
-}
-
-void
-as_path_format(const struct adata *path, byte *bb, uint size)
-{
- buffer buf = { .start = bb, .pos = bb, .end = bb + size }, *b = &buf;
- const byte *pos = path->data;
- const byte *end = pos + path->length;
- const char *ops, *cls;
-
- b->pos[0] = 0;
-
- while (pos < end)
- {
- uint type = pos[0];
- uint len = pos[1];
- pos += 2;
-
- switch (type)
- {
- case AS_PATH_SET: ops = "{"; cls = "}"; break;
- case AS_PATH_SEQUENCE: ops = NULL; cls = NULL; break;
- case AS_PATH_CONFED_SEQUENCE: ops = "("; cls = ")"; break;
- case AS_PATH_CONFED_SET: ops = "({"; cls = "})"; break;
- default: bug("Invalid path segment");
- }
-
- if (ops)
- buffer_puts(b, ops);
-
- while (len--)
- {
- buffer_print(b, len ? "%u " : "%u", get_as(pos));
- pos += BS;
- }
-
- if (cls)
- buffer_puts(b, cls);
-
- if (pos < end)
- buffer_puts(b, " ");
- }
-
- /* Handle overflow */
- if (b->pos == b->end)
- strcpy(b->end - 12, "...");
-}
-
-int
-as_path_getlen(const struct adata *path)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
- uint res = 0;
-
- while (pos < end)
- {
- uint t = pos[0];
- uint l = pos[1];
- uint n = 0;
-
- switch (t)
- {
- case AS_PATH_SET: n = 1; break;
- case AS_PATH_SEQUENCE: n = l; break;
- case AS_PATH_CONFED_SEQUENCE: n = 0; break;
- case AS_PATH_CONFED_SET: n = 0; break;
- default: bug("as_path_getlen: Invalid path segment");
- }
-
- res += n;
- pos += 2 + BS * l;
- }
-
- return res;
-}
-
-int
-as_path_get_last(const struct adata *path, u32 *orig_as)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
- int found = 0;
- u32 val = 0;
-
- while (pos < end)
- {
- uint type = pos[0];
- uint len = pos[1];
- pos += 2;
-
- if (!len)
- continue;
-
- switch (type)
- {
- case AS_PATH_SET:
- case AS_PATH_CONFED_SET:
- found = 0;
- break;
-
- case AS_PATH_SEQUENCE:
- case AS_PATH_CONFED_SEQUENCE:
- val = get_as(pos + BS * (len - 1));
- found = 1;
- break;
-
- default:
- bug("Invalid path segment");
- }
-
- pos += BS * len;
- }
-
- if (found)
- *orig_as = val;
- return found;
-}
-
-u32
-as_path_get_last_nonaggregated(const struct adata *path)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
- u32 val = 0;
-
- while (pos < end)
- {
- uint type = pos[0];
- uint len = pos[1];
- pos += 2;
-
- if (!len)
- continue;
-
- switch (type)
- {
- case AS_PATH_SET:
- case AS_PATH_CONFED_SET:
- return val;
-
- case AS_PATH_SEQUENCE:
- case AS_PATH_CONFED_SEQUENCE:
- val = get_as(pos + BS * (len - 1));
- break;
-
- default:
- bug("Invalid path segment");
- }
-
- pos += BS * len;
- }
-
- return val;
-}
-
-int
-as_path_get_first(const struct adata *path, u32 *last_as)
-{
- const u8 *p = path->data;
-
- if ((path->length == 0) || (p[0] != AS_PATH_SEQUENCE) || (p[1] == 0))
- return 0;
-
- *last_as = get_as(p+2);
- return 1;
-}
-
-int
-as_path_get_first_regular(const struct adata *path, u32 *last_as)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
-
- while (pos < end)
- {
- uint type = pos[0];
- uint len = pos[1];
- pos += 2;
-
- switch (type)
- {
- case AS_PATH_SET:
- return 0;
-
- case AS_PATH_SEQUENCE:
- if (len == 0)
- return 0;
-
- *last_as = get_as(pos);
- return 1;
-
- case AS_PATH_CONFED_SEQUENCE:
- case AS_PATH_CONFED_SET:
- break;
-
- default:
- bug("Invalid path segment");
- }
-
- pos += BS * len;
- }
-
- return 0;
-}
-
-int
-as_path_contains(const struct adata *path, u32 as, int min)
-{
- const u8 *p = path->data;
- const u8 *q = p+path->length;
- int num = 0;
- int i, n;
-
- while (p<q)
- {
- n = p[1];
- p += 2;
- for(i=0; i<n; i++)
- {
- if (get_as(p) == as)
- if (++num == min)
- return 1;
- p += BS;
- }
- }
- return 0;
-}
-
-int
-as_path_match_set(const struct adata *path, const struct f_tree *set)
-{
- const u8 *p = path->data;
- const u8 *q = p+path->length;
- int i, n;
-
- while (p<q)
- {
- n = p[1];
- p += 2;
- for (i=0; i<n; i++)
- {
- struct f_val v = {T_INT, .val.i = get_as(p)};
- if (find_tree(set, &v))
- return 1;
- p += BS;
- }
- }
-
- return 0;
-}
-
-const struct adata *
-as_path_filter(struct linpool *pool, const struct adata *path, const struct f_val *set, int pos)
-{
- ASSERT((set->type == T_SET) || (set->type == T_INT));
-
- if (!path)
- return NULL;
-
- int len = path->length;
- const u8 *p = path->data;
- const u8 *q = path->data + len;
- u8 *d, *d2;
- int i, bt, sn, dn;
- u8 buf[len];
-
- d = buf;
- while (p<q)
- {
- /* Read block header (type and length) */
- bt = p[0];
- sn = p[1];
- dn = 0;
- p += 2;
- d2 = d + 2;
-
- for (i = 0; i < sn; i++)
- {
- u32 as = get_as(p);
- int match;
-
- if (set->type == T_SET)
- {
- struct f_val v = {T_INT, .val.i = as};
- match = !!find_tree(set->val.t, &v);
- }
- else /* T_INT */
- match = (as == set->val.i);
-
- if (match == pos)
- {
- put_as(d2, as);
- d2 += BS;
- dn++;
- }
-
- p += BS;
- }
-
- if (dn > 0)
- {
- /* Nonempty block, set block header and advance */
- d[0] = bt;
- d[1] = dn;
- d = d2;
- }
- }
-
- uint nl = d - buf;
- if (nl == path->length)
- return path;
-
- struct adata *res = lp_alloc(pool, sizeof(struct adata) + nl);
- res->length = nl;
- memcpy(res->data, buf, nl);
-
- return res;
-}
-
-int
-as_path_walk(const struct adata *path, uint *pos, uint *val)
-{
- if (!path)
- return 0;
-
- const u8 *p = path->data;
- const u8 *q = p + path->length;
- uint n, x = *pos;
-
- while (p < q)
- {
- n = p[1];
- p += 2;
-
- if (x < n)
- {
- *val = get_as(p + x * BS);
- *pos += 1;
- return 1;
- }
-
- p += n * BS;
- x -= n;
- }
-
- return 0;
-}
-
-
-struct pm_pos
-{
- u8 set;
- u8 mark;
- union
- {
- const char *sp;
- u32 asn;
- } val;
-};
-
-static int
-parse_path(const struct adata *path, struct pm_pos *pp)
-{
- const byte *pos = path->data;
- const byte *end = pos + path->length;
- struct pm_pos *op = pp;
- uint i;
-
- while (pos < end)
- {
- uint type = pos[0];
- uint len = pos[1];
- pos += 2;
-
- switch (type)
- {
- case AS_PATH_SET:
- case AS_PATH_CONFED_SET:
- pp->set = 1;
- pp->mark = 0;
- pp->val.sp = pos - 1;
- pp++;
-
- pos += BS * len;
- break;
-
- case AS_PATH_SEQUENCE:
- case AS_PATH_CONFED_SEQUENCE:
- for (i = 0; i < len; i++)
- {
- pp->set = 0;
- pp->mark = 0;
- pp->val.asn = get_as(pos);
- pp++;
-
- pos += BS;
- }
- break;
-
- default:
- bug("Invalid path segment");
- }
- }
-
- return pp - op;
-}
-
-static int
-pm_match_val(const struct pm_pos *pos, u32 asn, u32 asn2)
-{
- u32 gas;
- if (! pos->set)
- return ((pos->val.asn >= asn) && (pos->val.asn <= asn2));
-
- const u8 *p = pos->val.sp;
- int len = *p++;
- int i;
-
- for (i = 0; i < len; i++)
- {
- gas = get_as(p + i * BS);
-
- if ((gas >= asn) && (gas <= asn2))
- return 1;
- }
-
- return 0;
-}
-
-static int
-pm_match_set(const struct pm_pos *pos, const struct f_tree *set)
-{
- struct f_val asn = { .type = T_INT };
-
- if (! pos->set)
- {
- asn.val.i = pos->val.asn;
- return !!find_tree(set, &asn);
- }
-
- const u8 *p = pos->val.sp;
- int len = *p++;
- int i;
-
- for (i = 0; i < len; i++)
- {
- asn.val.i = get_as(p + i * BS);
- if (find_tree(set, &asn))
- return 1;
- }
-
- return 0;
-}
-
-static inline int
-pm_match(const struct pm_pos *pos, const struct f_path_mask_item *mask, u32 asn, u32 asn2)
-{
- return ((mask->kind == PM_QUESTION) ||
- ((mask->kind != PM_ASN_SET) ?
- pm_match_val(pos, asn, asn2) :
- pm_match_set(pos, mask->set)));
-}
-
-static void
-pm_mark(struct pm_pos *pos, int *i, int plen, int *nl, int *nh)
-{
- int j = *i;
-
- if (pos[j].set)
- do { pos[j].mark = 1; j++; }
- while ((j < plen) && pos[j].set);
- else
- j++;
-
- pos[j].mark = 1;
-
- /* Update low, high based on first and last marked pos */
- int l = pos[*i].set ? *i : j;
-
- *nl = (*nl < 0) ? l : MIN(*nl, l);
- *nh = MAX(*nh, j);
- *i = j;
-}
-
-/* AS path matching is nontrivial. Because AS path can
- * contain sets, it is not a plain wildcard matching. A set
- * in an AS path is interpreted as it might represent any
- * sequence of AS numbers from that set (possibly with
- * repetitions). So it is also a kind of a pattern,
- * more complicated than a path mask.
- *
- * The algorithm for AS path matching is a variant
- * of nondeterministic finite state machine, where
- * positions in AS path are states, and items in
- * path mask are input for that finite state machine.
- * During execution of the algorithm we maintain a set
- * of marked states - a state is marked if it can be
- * reached by any walk through NFSM with regard to
- * currently processed part of input. When we process
- * next part of mask, we advance each marked state.
- * We start with marked first position, when we
- * run out of marked positions, we reject. When
- * we process the whole mask, we accept if final position
- * (auxiliary position after last real position in AS path)
- * is marked.
- */
-int
-as_path_match(const struct adata *path, const struct f_path_mask *mask)
-{
- struct pm_pos pos[2048 + 1];
- int plen = parse_path(path, pos);
- int l, h, i, nh, nl, last, loop;
- u32 val = 0;
- u32 val2 = 0;
-
- /* l and h are bound of interval of positions where
- are marked states */
-
- pos[plen].set = 0;
- pos[plen].mark = 0;
-
- l = h = loop = 0;
- pos[0].mark = 1;
-
- for (uint m=0; m < mask->len; m++)
- {
- /* We remove this mark to not step after pos[plen] */
- pos[plen].mark = 0;
-
- switch (mask->item[m].kind)
- {
- case PM_ASTERISK:
- for (i = l; i <= plen; i++)
- pos[i].mark = 1;
- h = plen;
- break;
-
- case PM_LOOP:
- loop = 1;
- break;
-
- case PM_ASN: /* Define single ASN as ASN..ASN - very narrow interval */
- val2 = val = mask->item[m].asn;
- goto step;
- case PM_ASN_EXPR:
- bug("Expressions should be evaluated on AS path mask construction.");
- case PM_ASN_RANGE:
- val = mask->item[m].from;
- val2 = mask->item[m].to;
- goto step;
- case PM_QUESTION:
- case PM_ASN_SET:
- step:
- nh = nl = -1;
- last = plen;
- for (i = h; i >= l; i--)
- if (pos[i].mark)
- {
- pos[i].mark = 0;
- int j = i;
-
- match:
- if (pm_match(pos + j, &mask->item[m], val, val2))
- {
- pm_mark(pos, &j, plen, &nl, &nh);
- if (loop && (j < last))
- goto match;
- }
-
- last = i;
- }
-
- if (nh < 0)
- return 0;
-
- h = nh;
- l = nl;
- loop = 0;
- break;
- }
- }
-
- return pos[plen].mark;
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 21:57:25 +0000