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-rw-r--r--nest/a-path.c209
-rw-r--r--nest/attrs.h21
2 files changed, 191 insertions, 39 deletions
diff --git a/nest/a-path.c b/nest/a-path.c
index 1b08f80..f466691 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -14,38 +14,139 @@
#include "lib/unaligned.h"
#include "lib/string.h"
+
+/* Global AS4 support, shared by all BGP instances.
+ * This specifies whether BA_AS_PATH attributes contain 2 or 4 B per ASN
+ */
+
+int bgp_as4_support = 1;
+
+static void
+put_as(byte *data, u32 as)
+{
+ if (bgp_as4_support)
+ put_u32(data, as);
+ else if (as <= 0xFFFF)
+ put_u16(data, as);
+ else
+ bug("put_as: Try to put 32bit AS to 16bit AS Path");
+}
+
+static inline u32
+get_as(byte *data)
+{
+ return bgp_as4_support ? get_u32(data) : get_u16(data);
+}
+
struct adata *
-as_path_prepend(struct linpool *pool, struct adata *olda, int as)
+as_path_prepend(struct linpool *pool, struct adata *olda, u32 as)
{
+ int bs = bgp_as4_support ? 4 : 2;
struct adata *newa;
- if (olda->length && olda->data[0] == AS_PATH_SEQUENCE &&
- olda->data[1] < 255) /* Starting with sequence => just prepend the AS number */
+ 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;
+ 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+4, olda->data+2, olda->length-2);
+ memcpy(newa->data + bs + 2, olda->data + 2, olda->length - 2);
}
- else /* Create new path segment */
+ else /* Create new path segment */
{
- newa = lp_alloc(pool, sizeof(struct adata) + olda->length + 4);
- newa->length = olda->length + 4;
- newa->data[0] = 2;
+ 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+4, olda->data, olda->length);
+ memcpy(newa->data + bs + 2, olda->data, olda->length);
}
- put_u16(newa->data+2, as);
+ put_as(newa->data + 2, as);
return newa;
}
+int
+as_path_convert_to_old(struct adata *path, byte *dst, int *new_used)
+{
+ byte *src = path->data;
+ byte *src_end = src + path->length;
+ byte *dst_start = dst;
+ u32 as;
+ int i, n;
+ *new_used = 0;
+
+ while (src < src_end)
+ {
+ n = src[1];
+ *dst++ = *src++;
+ *dst++ = *src++;
+
+ 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;
+ }
+ }
+
+ return dst - dst_start;
+}
+
+int
+as_path_convert_to_new(struct adata *path, byte *dst, int req_as)
+{
+ byte *src = path->data;
+ byte *src_end = src + path->length;
+ byte *dst_start = dst;
+ u32 as;
+ int i, t, n;
+
+
+ while ((src < src_end) && (req_as > 0))
+ {
+ t = *src++;
+ n = *src++;
+
+ if (t == AS_PATH_SEQUENCE)
+ {
+ if (n > req_as)
+ n = req_as;
+
+ req_as -= n;
+ }
+ else // t == AS_PATH_SET
+ req_as--;
+
+ *dst++ = t;
+ *dst++ = n;
+
+ for(i=0; i<n; i++)
+ {
+ as = get_u16(src);
+ put_u32(dst, as);
+ src += 2;
+ dst += 4;
+ }
+ }
+
+ return dst - dst_start;
+}
+
void
as_path_format(struct adata *path, byte *buf, unsigned int size)
{
+ int bs = bgp_as4_support ? 4 : 2;
byte *p = path->data;
byte *e = p + path->length;
- byte *end = buf + size - 8;
+ byte *end = buf + size - 16;
int sp = 1;
int l, isset;
@@ -69,8 +170,8 @@ as_path_format(struct adata *path, byte *buf, unsigned int size)
{
if (!sp)
*buf++ = ' ';
- buf += bsprintf(buf, "%d", get_u16(p));
- p += 2;
+ buf += bsprintf(buf, "%u", get_as(p));
+ p += bs;
sp = 0;
}
if (isset)
@@ -86,6 +187,7 @@ as_path_format(struct adata *path, byte *buf, unsigned int size)
int
as_path_getlen(struct adata *path)
{
+ int bs = bgp_as4_support ? 4 : 2;
int res = 0;
u8 *p = path->data;
u8 *q = p+path->length;
@@ -95,8 +197,8 @@ as_path_getlen(struct adata *path)
{
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;
+ 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");
}
}
@@ -104,9 +206,11 @@ as_path_getlen(struct adata *path)
}
int
-as_path_get_first(struct adata *path)
+as_path_get_first(struct adata *path, u32 *orig_as)
{
- int res = -1;
+ int bs = bgp_as4_support ? 4 : 2;
+ int found = 0;
+ u32 res = 0;
u8 *p = path->data;
u8 *q = p+path->length;
int len;
@@ -117,36 +221,70 @@ as_path_get_first(struct adata *path)
{
case AS_PATH_SET:
if (len = *p++)
- res = get_u16(p);
- p += 2*len;
+ {
+ found = 1;
+ res = get_as(p);
+ p += bs * len;
+ }
break;
case AS_PATH_SEQUENCE:
if (len = *p++)
- res = get_u16(p+2*(len-1));
- p += 2*len;
+ {
+ found = 1;
+ res = get_as(p + bs * (len - 1));
+ p += bs * len;
+ }
break;
default: bug("as_path_get_first: Invalid path segment");
}
}
- return res;
+
+ *orig_as = res;
+ return found;
}
+int
+as_path_is_member(struct adata *path, u32 as)
+{
+ int bs = bgp_as4_support ? 4 : 2;
+ u8 *p = path->data;
+ u8 *q = p+path->length;
+ int i, n;
+
+ while (p<q)
+ {
+ n = p[1];
+ p += 2;
+ for(i=0; i<n; i++)
+ {
+ if (get_as(p) == as)
+ return 1;
+ p += bs;
+ }
+ }
+ return 0;
+}
+
+
+
#define MASK_PLUS do { mask = mask->next; if (!mask) return next == q; \
- asterisk = (mask->val == PM_ANY); \
+ asterisk = mask->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 bs = bgp_as4_support ? 4 : 2;
int i;
int asterisk = 0;
u8 *p = path->data;
u8 *q = p+path->length;
int len;
u8 *next;
+ u32 as;
- asterisk = (mask->val == PM_ANY);
+ asterisk = mask->any;
if (asterisk)
{ mask = mask->next; if (!mask) return 1; }
@@ -156,20 +294,21 @@ as_path_match(struct adata *path, struct f_path_mask *mask)
len = *p++;
{
u8 *p_save = p;
- next = p_save + 2*len;
+ next = p_save + bs * len;
retry:
p = p_save;
for (i=0; i<len; i++) {
- if (asterisk && (get_u16(p) == mask->val)) {
+ as = get_as(p);
+ if (asterisk && (as == mask->val)) {
MASK_PLUS;
goto retry;
}
- if (!asterisk && (get_u16(p) == mask->val)) {
+ if (!asterisk && (as == mask->val)) {
p = next;
MASK_PLUS;
goto okay;
}
- p+=2;
+ p += bs;
}
if (!asterisk)
return 0;
@@ -180,15 +319,15 @@ as_path_match(struct adata *path, struct f_path_mask *mask)
case AS_PATH_SEQUENCE:
len = *p++;
for (i=0; i<len; i++) {
- next = p+2;
- if (asterisk && (get_u16(p) == mask->val))
+ as = get_as(p);
+ if (asterisk && (as == mask->val))
MASK_PLUS;
else if (!asterisk) {
- if (get_u16(p) != mask->val)
+ if (as != mask->val)
return 0;
MASK_PLUS;
}
- p+=2;
+ p += bs;
}
break;
diff --git a/nest/attrs.h b/nest/attrs.h
index abd6b9e..f63f2e4 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -14,16 +14,29 @@
#define AS_PATH_SET 1 /* Types of path segments */
#define AS_PATH_SEQUENCE 2
-struct adata *as_path_prepend(struct linpool *pool, struct adata *olda, int as);
+#define AS_PATH_MAXLEN 10000
+
+#define AS_TRANS 23456
+/* AS_TRANS is used when we need to store 32bit ASN larger than 0xFFFF
+ * to 16bit slot (like in 16bit AS_PATH). See RFC 4893 for details
+ */
+
+struct adata *as_path_prepend(struct linpool *pool, struct adata *olda, u32 as);
+int as_path_convert_to_old(struct adata *path, byte *dst, int *new_used);
+int as_path_convert_to_new(struct adata *path, byte *dst, int req_as);
void as_path_format(struct adata *path, byte *buf, unsigned int size);
int as_path_getlen(struct adata *path);
-int as_path_get_first(struct adata *path);
+int as_path_get_first(struct adata *path, u32 *orig_as);
+int as_path_is_member(struct adata *path, u32 as);
+
struct f_path_mask {
struct f_path_mask *next;
- int val;
+ u32 val;
+ int any;
};
-#define PM_ANY -1
+
+// #define PM_ANY -1
int as_path_match(struct adata *path, struct f_path_mask *mask);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 18:17:19 +0100