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-rw-r--r--nest/a-path.c434
1 files changed, 318 insertions, 116 deletions
diff --git a/nest/a-path.c b/nest/a-path.c
index 158cc93b..6ced703d 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -22,112 +22,313 @@
#define get_as get_u32
#define BS 4 /* Default block size of ASN (autonomous system number) */
-struct adata *
-as_path_prepend(struct linpool *pool, struct adata *olda, u32 as)
+#define BAD(DSC, VAL) ({ err_dsc = DSC; err_val = VAL; goto bad; })
+
+int
+as_path_valid(byte *data, uint len, int bs, char *err, uint elen)
{
- struct adata *newa;
+ 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);
+
+ /* XXXX handle CONFED segments */
+ if ((type != AS_PATH_SET) && (type != AS_PATH_SEQUENCE))
+ BAD("unknown segment", type);
+
+ if (pos[1] == 0)
+ BAD("zero-length segment", type);
- if (olda->length && olda->data[0] == AS_PATH_SEQUENCE && olda->data[1] < 255)
- /* Starting with sequence => just prepend the AS number */
+ 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, byte *src, uint len)
+{
+ byte *dst0 = dst;
+ byte *end = src + len;
+ uint i, n;
+
+ while (src < end)
+ {
+ n = src[1];
+ *dst++ = *src++;
+ *dst++ = *src++;
+
+ for (i = 0; i < n; i++)
{
- int nl = olda->length + BS;
- newa = lp_alloc(pool, sizeof(struct adata) + nl);
- newa->length = nl;
- newa->data[0] = AS_PATH_SEQUENCE;
- newa->data[1] = olda->data[1] + 1;
- memcpy(newa->data + BS + 2, olda->data + 2, olda->length - 2);
+ put_u32(dst, get_u16(src));
+ src += 2;
+ dst += 4;
}
- else /* Create new path segment */
+ }
+
+ return dst - dst0;
+}
+
+int
+as_path_32to16(byte *dst, byte *src, uint len)
+{
+ byte *dst0 = dst;
+ byte *end = src + len;
+ uint i, n;
+
+ while (src < end)
+ {
+ n = src[1];
+ *dst++ = *src++;
+ *dst++ = *src++;
+
+ for (i = 0; i < n; i++)
{
- int nl = olda->length + BS + 2;
- newa = lp_alloc(pool, sizeof(struct adata) + nl);
- newa->length = nl;
- newa->data[0] = AS_PATH_SEQUENCE;
- newa->data[1] = 1;
- memcpy(newa->data + BS + 2, olda->data, olda->length);
+ put_u16(dst, get_u32(src));
+ src += 4;
+ dst += 2;
}
- put_as(newa->data + 2, as);
- return newa;
+ }
+
+ return dst - dst0;
}
int
-as_path_convert_to_old(struct adata *path, byte *dst, int *new_used)
+as_path_contains_as4(const struct adata *path)
{
- byte *src = path->data;
- byte *src_end = src + path->length;
- byte *dst_start = dst;
- u32 as;
- int i, n;
- *new_used = 0;
+ const byte *pos = path->data;
+ const byte *end = pos + path->length;
+ uint i, n;
+
+ while (pos < end)
+ {
+ n = pos[1];
+ pos += 2;
- while (src < src_end)
+ for (i = 0; i < n; i++)
{
- n = src[1];
- *dst++ = *src++;
- *dst++ = *src++;
+ if (get_as(pos) > 0xFFFF)
+ return 1;
- for(i=0; i<n; i++)
- {
- as = get_u32(src);
- if (as > 0xFFFF)
- {
- as = AS_TRANS;
- *new_used = 1;
- }
- put_u16(dst, as);
- src += 4;
- dst += 2;
- }
+ pos += BS;
}
+ }
- return dst - dst_start;
+ return 0;
}
int
-as_path_convert_to_new(struct adata *path, byte *dst, int req_as)
+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;
+}
+
+static void
+as_path_strip_confed_(byte *dst, const byte *src, uint len)
+{
+ const byte *end = src + len;
+
+ 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;
+ }
+}
+
+struct adata *
+as_path_strip_confed(struct linpool *pool, const struct adata *op)
+{
+ struct adata *np = lp_alloc_adata(pool, op->length);
+ as_path_strip_confed_(np->data, op->data, op->length);
+ return np;
+}
+
+struct adata *
+as_path_prepend2(struct linpool *pool, const struct adata *op, int seq, u32 as, int strip)
{
- byte *src = path->data;
- byte *src_end = src + path->length;
- byte *dst_start = dst;
+ 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];
+
+ if (strip)
+ as_path_strip_confed_(dst, pos, len);
+ else
+ 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;
- int i, t, n;
+ /* 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;
- while ((src < src_end) && (req_as > 0))
+ for (i = 0; i < n; i++)
{
- t = *src++;
- n = *src++;
+ as = get_as(pos);
+ if (as > 0xFFFF)
+ put_as(pos, AS_TRANS);
- if (t == AS_PATH_SEQUENCE)
- {
- if (n > req_as)
- n = req_as;
+ pos += BS;
+ }
+ }
- req_as -= n;
- }
- else // t == AS_PATH_SET
- req_as--;
+ return res;
+}
- *dst++ = t;
- *dst++ = n;
+/*
+ * 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.
+ * In contrast to other as_path_* functions, @path is modified in place.
+ */
+void
+as_path_cut(struct adata *path, uint num)
+{
+ byte *pos = path->data;
+ byte *end = pos + path->length;
- for(i=0; i<n; i++)
- {
- as = get_u16(src);
- put_u32(dst, as);
- src += 2;
- dst += 4;
- }
+ 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)
+ {
+ if (num)
+ {
+ pos[1] = num;
+ pos += 2 + BS * num;
+ }
+
+ break;
}
- return dst - dst_start;
+ num -= n;
+ pos += 2 + BS * l;
+ }
+
+ path->length = pos - path->data;
+}
+
+/*
+ * Merge (concatenate) paths @p1 and @p2 and return the result.
+ * In contrast to other as_path_* functions, @p1 and @p2 may be reused.
+ */
+struct adata *
+as_path_merge(struct linpool *pool, struct adata *p1, 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(struct adata *path, byte *buf, uint size)
+as_path_format(const struct adata *path, byte *buf, uint size)
{
- byte *p = path->data;
- byte *e = p + path->length;
+ const byte *p = path->data;
+ const byte *e = p + path->length;
byte *end = buf + size - 16;
int sp = 1;
int l, isset;
@@ -167,38 +368,41 @@ as_path_format(struct adata *path, byte *buf, uint size)
}
int
-as_path_getlen(struct adata *path)
+as_path_getlen(const struct adata *path)
{
- return as_path_getlen_int(path, BS);
-}
+ const byte *pos = path->data;
+ const byte *end = pos + path->length;
+ uint res = 0;
-int
-as_path_getlen_int(struct adata *path, int bs)
-{
- int res = 0;
- u8 *p = path->data;
- u8 *q = p+path->length;
- int len;
+ while (pos < end)
+ {
+ uint t = pos[0];
+ uint l = pos[1];
+ uint n = 0;
- while (p<q)
+ switch (t)
{
- switch (*p++)
- {
- case AS_PATH_SET: len = *p++; res++; p += bs * len; break;
- case AS_PATH_SEQUENCE: len = *p++; res += len; p += bs * len; break;
- default: bug("as_path_getlen: Invalid path segment");
- }
+ 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(struct adata *path, u32 *orig_as)
+as_path_get_last(const struct adata *path, u32 *orig_as)
{
int found = 0;
u32 res = 0;
- u8 *p = path->data;
- u8 *q = p+path->length;
+ const u8 *p = path->data;
+ const u8 *q = p+path->length;
int len;
while (p<q)
@@ -230,10 +434,10 @@ as_path_get_last(struct adata *path, u32 *orig_as)
}
u32
-as_path_get_last_nonaggregated(struct adata *path)
+as_path_get_last_nonaggregated(const struct adata *path)
{
- u8 *p = path->data;
- u8 *q = p+path->length;
+ const u8 *p = path->data;
+ const u8 *q = p+path->length;
u32 res = 0;
int len;
@@ -257,11 +461,10 @@ as_path_get_last_nonaggregated(struct adata *path)
return res;
}
-
int
-as_path_get_first(struct adata *path, u32 *last_as)
+as_path_get_first(const struct adata *path, u32 *last_as)
{
- u8 *p = path->data;
+ const u8 *p = path->data;
if ((path->length == 0) || (p[0] != AS_PATH_SEQUENCE) || (p[1] == 0))
return 0;
@@ -273,10 +476,10 @@ as_path_get_first(struct adata *path, u32 *last_as)
}
int
-as_path_contains(struct adata *path, u32 as, int min)
+as_path_contains(const struct adata *path, u32 as, int min)
{
- u8 *p = path->data;
- u8 *q = p+path->length;
+ const u8 *p = path->data;
+ const u8 *q = p+path->length;
int num = 0;
int i, n;
@@ -296,10 +499,10 @@ as_path_contains(struct adata *path, u32 as, int min)
}
int
-as_path_match_set(struct adata *path, struct f_tree *set)
+as_path_match_set(const struct adata *path, struct f_tree *set)
{
- u8 *p = path->data;
- u8 *q = p+path->length;
+ const u8 *p = path->data;
+ const u8 *q = p+path->length;
int i, n;
while (p<q)
@@ -325,8 +528,8 @@ as_path_filter(struct linpool *pool, struct adata *path, struct f_tree *set, u32
return NULL;
int len = path->length;
- u8 *p = path->data;
- u8 *q = path->data + len;
+ const u8 *p = path->data;
+ const u8 *q = path->data + len;
u8 *d, *d2;
int i, bt, sn, dn;
u8 buf[len];
@@ -388,16 +591,16 @@ struct pm_pos
u8 mark;
union
{
- char *sp;
+ const char *sp;
u32 asn;
} val;
};
static int
-parse_path(struct adata *path, struct pm_pos *pos)
+parse_path(const struct adata *path, struct pm_pos *pos)
{
- u8 *p = path->data;
- u8 *q = p + path->length;
+ const u8 *p = path->data;
+ const u8 *q = p + path->length;
struct pm_pos *opos = pos;
int i, len;
@@ -429,11 +632,10 @@ parse_path(struct adata *path, struct pm_pos *pos)
default:
bug("as_path_match: Invalid path component");
}
-
+
return pos - opos;
}
-
static int
pm_match(struct pm_pos *pos, u32 asn, u32 asn2)
{
@@ -441,7 +643,7 @@ pm_match(struct pm_pos *pos, u32 asn, u32 asn2)
if (! pos->set)
return ((pos->val.asn >= asn) && (pos->val.asn <= asn2));
- u8 *p = pos->val.sp;
+ const u8 *p = pos->val.sp;
int len = *p++;
int i;
@@ -463,7 +665,7 @@ pm_mark(struct pm_pos *pos, int i, int plen, int *nl, int *nh)
if (pos[i].set)
pos[i].mark = 1;
-
+
for (j = i + 1; (j < plen) && pos[j].set && (! pos[j].mark); j++)
pos[j].mark = 1;
pos[j].mark = 1;
@@ -500,7 +702,7 @@ pm_mark(struct pm_pos *pos, int i, int plen, int *nl, int *nh)
* is marked.
*/
int
-as_path_match(struct adata *path, struct f_path_mask *mask)
+as_path_match(const struct adata *path, struct f_path_mask *mask)
{
struct pm_pos pos[2048 + 1];
int plen = parse_path(path, pos);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 23:45:15 +0000