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-rw-r--r--proto/bgp/attrs.c210
-rw-r--r--proto/bgp/bgp.c2
-rw-r--r--proto/bgp/bgp.h10
-rw-r--r--proto/bgp/config.Y4
-rw-r--r--proto/bgp/packets.c51
5 files changed, 254 insertions, 23 deletions
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index bf747cb..29d6acb 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -6,10 +6,220 @@
* Can be freely distributed and used under the terms of the GNU GPL.
*/
+#define LOCAL_DEBUG
+
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "conf/conf.h"
+#include "lib/resource.h"
+#include "lib/string.h"
+#include "lib/unaligned.h"
#include "bgp.h"
+
+static int bgp_check_origin(byte *a, int len)
+{
+ if (len > 2)
+ return 6;
+ return 0;
+}
+
+static int bgp_check_path(byte *a, int len)
+{
+ while (len)
+ {
+ DBG("Path segment %02x %02x\n", a[0], a[1]);
+ if (len < 2 ||
+ a[0] != BGP_PATH_AS_SET && a[0] != BGP_PATH_AS_SEQUENCE ||
+ 2*a[1] + 2 > len)
+ return 11;
+ len -= 2*a[1] + 2;
+ a += 2*a[1] + 2;
+ }
+ return 0;
+}
+
+static int bgp_check_next_hop(byte *a, int len)
+{
+ ip_addr addr;
+
+ memcpy(&addr, a, len);
+ if (ipa_classify(ipa_ntoh(addr)) & IADDR_HOST)
+ return 0;
+ else
+ return 8;
+}
+
+struct attr_desc {
+ int expected_length;
+ int expected_flags;
+ int type;
+ int (*validate)(byte *attr, int len);
+};
+
+static struct attr_desc bgp_attr_table[] = {
+ { -1, 0, 0, NULL }, /* Undefined */
+ { 1, BAF_TRANSITIVE, EAF_TYPE_INT, bgp_check_origin }, /* BA_ORIGIN */
+ { -1, BAF_TRANSITIVE, EAF_TYPE_AS_PATH, bgp_check_path }, /* BA_AS_PATH */
+ { 4, BAF_TRANSITIVE, EAF_TYPE_IP_ADDRESS, bgp_check_next_hop }, /* BA_NEXT_HOP */
+ { 4, BAF_OPTIONAL, EAF_TYPE_INT, NULL }, /* BA_MULTI_EXIT_DISC */
+ { 4, BAF_OPTIONAL, EAF_TYPE_INT, NULL }, /* BA_LOCAL_PREF */
+ { 0, BAF_OPTIONAL, EAF_TYPE_OPAQUE, NULL }, /* BA_ATOMIC_AGGR */
+ { 6, BAF_OPTIONAL, EAF_TYPE_OPAQUE, NULL }, /* BA_AGGREGATOR */
+#if 0
+ /* FIXME: Handle community lists */
+ { 0, 0 }, /* BA_COMMUNITY */
+ { 0, 0 }, /* BA_ORIGINATOR_ID */
+ { 0, 0 }, /* BA_CLUSTER_LIST */
+#endif
+};
+
+static int bgp_mandatory_attrs[] = { BA_ORIGIN, BA_AS_PATH, BA_NEXT_HOP };
+
+struct rta *
+bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct linpool *pool)
+{
+ struct bgp_proto *bgp = conn->bgp;
+ rta *a = lp_alloc(pool, sizeof(struct rta));
+ unsigned int flags, code, l, errcode, i, type;
+ byte *z, *attr_start;
+ byte seen[256/8];
+ eattr *e;
+ ea_list *ea;
+ struct adata *ad;
+ neighbor *neigh;
+ ip_addr nexthop;
+
+ a->proto = &bgp->p;
+ a->source = RTS_BGP;
+ a->scope = SCOPE_UNIVERSE;
+ a->cast = RTC_UNICAST;
+ a->dest = RTD_ROUTER;
+ a->flags = 0;
+ a->aflags = 0;
+ a->from = bgp->cf->remote_ip;
+ a->eattrs = NULL;
+
+ /* Parse the attributes */
+ bzero(seen, sizeof(seen));
+ DBG("BGP: Parsing attributes\n");
+ while (len)
+ {
+ if (len < 2)
+ goto malformed;
+ attr_start = attr;
+ flags = *attr++;
+ code = *attr++;
+ len -= 2;
+ if (flags & BAF_EXT_LEN)
+ {
+ if (len < 2)
+ goto malformed;
+ l = get_u16(attr);
+ attr += 2;
+ len -= 2;
+ }
+ else
+ {
+ if (len < 1)
+ goto malformed;
+ l = *attr++;
+ len--;
+ }
+ if (l > len)
+ goto malformed;
+ len -= l;
+ z = attr;
+ attr += l;
+ DBG("Attr %02x %02x %d\n", code, flags, l);
+ if (seen[code/8] & (1 << (code%8)))
+ goto malformed;
+ seen[code/8] |= (1 << (code%8));
+ if (code && code < sizeof(bgp_attr_table)/sizeof(bgp_attr_table[0]))
+ {
+ struct attr_desc *desc = &bgp_attr_table[code];
+ if (desc->expected_length >= 0 && desc->expected_length != (int) l)
+ { errcode = 5; goto err; }
+ if ((desc->expected_flags ^ flags) & (BAF_OPTIONAL | BAF_TRANSITIVE))
+ { errcode = 4; goto err; }
+ if (desc->validate && (errcode = desc->validate(z, l)))
+ goto err;
+ type = desc->type;
+ }
+ else /* Unknown attribute */
+ { /* FIXME: Send partial bit when forwarding */
+ if (!(flags & BAF_OPTIONAL))
+ { errcode = 2; goto err; }
+ type = EAF_TYPE_OPAQUE;
+ }
+ ea = lp_alloc(pool, sizeof(struct ea_list) + sizeof(struct eattr));
+ ea->next = a->eattrs;
+ a->eattrs = ea;
+ ea->flags = 0;
+ ea->count = 1;
+ ea->attrs[0].id = EA_CODE(EAP_BGP, code);
+ ea->attrs[0].flags = flags;
+ ea->attrs[0].type = type;
+ if (type & EAF_EMBEDDED)
+ ad = NULL;
+ else
+ {
+ ad = lp_alloc(pool, sizeof(struct adata) + l);
+ ea->attrs[0].u.ptr = ad;
+ ad->length = l;
+ memcpy(ad->data, z, l);
+ }
+ switch (type)
+ {
+ case EAF_TYPE_ROUTER_ID:
+ case EAF_TYPE_INT:
+ ea->attrs[0].u.data = get_u32(z);
+ break;
+ case EAF_TYPE_IP_ADDRESS:
+ *(ip_addr *)ad->data = ipa_ntoh(*(ip_addr *)ad->data);
+ break;
+ }
+ }
+
+ /* Check if all mandatory attributes are present */
+ for(i=0; i < sizeof(bgp_mandatory_attrs)/sizeof(bgp_mandatory_attrs[0]); i++)
+ {
+ code = bgp_mandatory_attrs[i];
+ if (!(seen[code/8] & (1 << (code%8))))
+ {
+ bgp_error(conn, 3, 3, code, 1);
+ return NULL;
+ }
+ }
+
+ /* Fill in the remaining rta fields */
+ e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
+ ASSERT(e);
+ nexthop = *(ip_addr *) e->u.ptr->data;
+ neigh = neigh_find(&bgp->p, &nexthop, 0);
+ if (!neigh)
+ {
+ if (bgp->cf->multihop)
+ neigh = neigh_find(&bgp->p, &bgp->cf->multihop_via, 0);
+ else
+ neigh = neigh_find(&bgp->p, &bgp->cf->remote_ip, 0);
+ }
+ if (!neigh || !neigh->iface)
+ {
+ DBG("BGP: No route to peer!\n"); /* FIXME */
+ return NULL;
+ }
+ a->gw = neigh->addr;
+ a->iface = neigh->iface;
+ return rta_lookup(a);
+
+malformed:
+ bgp_error(conn, 3, 1, len, 0);
+ return NULL;
+
+err:
+ bgp_error(conn, 3, errcode, code, 0); /* FIXME: Return attribute data! */
+ return NULL;
+}
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index e415756..e95e334 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -96,6 +96,8 @@ bgp_close_conn(struct bgp_conn *conn)
{
bgp_close(p);
p->conn = NULL;
+ if (conn->error_flag) /* FIXME: Enable automatically? */
+ p->p.disabled = 1;
proto_notify_state(&p->p, PS_DOWN);
}
}
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index e93b06e..eadf2b0 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -9,11 +9,14 @@
#ifndef _BIRD_BGP_H_
#define _BIRD_BGP_H_
+struct linpool;
+
struct bgp_config {
struct proto_config c;
unsigned int local_as, remote_as;
ip_addr remote_ip;
int multihop; /* Number of hops if multihop */
+ ip_addr multihop_via; /* Multihop: address to route to */
unsigned connect_retry_time;
unsigned hold_time, initial_hold_time;
unsigned keepalive_time;
@@ -63,6 +66,8 @@ void bgp_close_conn(struct bgp_conn *c);
/* attrs.c */
+struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool);
+
/* packets.c */
void bgp_schedule_packet(struct bgp_conn *conn, int type);
@@ -88,7 +93,7 @@ int bgp_rx(struct birdsock *sk, int size);
#define BA_AS_PATH 0x02 /* WM */
#define BA_NEXT_HOP 0x03 /* WM */
#define BA_MULTI_EXIT_DISC 0x04 /* ON */
-#define BA_LOCAL_PREF 0x05 /* WM */
+#define BA_LOCAL_PREF 0x05 /* WD */
#define BA_ATOMIC_AGGR 0x06 /* WD */
#define BA_AGGREGATOR 0x07 /* OT */
#define BA_COMMUNITY 0x08 /* [RFC1997] */ /* OT */
@@ -102,6 +107,9 @@ int bgp_rx(struct birdsock *sk, int size);
#define BA_MP_UNREACH_NLRI 0x0f
#define BA_EXTENDED_COMM 0x10 /* draft-ramachandra-bgp-ext-communities */
+#define BGP_PATH_AS_SET 1 /* Types of path segments */
+#define BGP_PATH_AS_SEQUENCE 2
+
/* BGP states */
#define BS_IDLE 0
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 0633e1c..f83191a 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -15,7 +15,7 @@ CF_HDR
CF_DECLS
CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
- MULTIHOP, STARTUP)
+ MULTIHOP, STARTUP, VIA)
CF_GRAMMAR
@@ -46,7 +46,7 @@ bgp_proto:
| bgp_proto STARTUP HOLD TIME NUM ';' { BGP_CFG->initial_hold_time = $5; }
| bgp_proto CONNECT RETRY TIME NUM ';' { BGP_CFG->connect_retry_time = $5; }
| bgp_proto KEEPALIVE TIME NUM ';' { BGP_CFG->connect_retry_time = $4; }
- | bgp_proto MULTIHOP NUM ';' { BGP_CFG->multihop = $3; }
+ | bgp_proto MULTIHOP NUM VIA IPA ';' { BGP_CFG->multihop = $3; BGP_CFG->multihop_via = $5; }
;
CF_CODE
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index 3bddbc9..7764999 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -218,24 +218,26 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
#define DECODE_PREFIX(pp, ll) do { \
int b = *pp++; \
int q; \
- ip_addr temp; \
ll--; \
if (b > BITS_PER_IP_ADDRESS) { bgp_error(conn, 3, 10, b, 0); return; } \
q = (b+7) / 8; \
- if (ll < q) goto too_small; \
- memcpy(&temp, pp, q); \
+ if (ll < q) goto malformed; \
+ memcpy(&prefix, pp, q); \
pp += q; \
ll -= q; \
- n.n.prefix = ipa_and(ipa_ntoh(temp), ipa_mkmask(b)); \
- n.n.pxlen = b; \
+ prefix = ipa_and(ipa_ntoh(prefix), ipa_mkmask(b)); \
+ pxlen = b; \
} while (0)
+/* FIXME: Check validity of prefixes */
static void
bgp_rx_update(struct bgp_conn *conn, byte *pkt, int len)
{
+ struct bgp_proto *bgp = conn->bgp;
byte *withdrawn, *attrs, *nlri;
- int withdrawn_len, attr_len, nlri_len;
- net n;
+ ip_addr prefix;
+ int withdrawn_len, attr_len, nlri_len, pxlen;
+ net *n;
rte e;
DBG("BGP: UPDATE\n");
@@ -246,45 +248,54 @@ bgp_rx_update(struct bgp_conn *conn, byte *pkt, int len)
/* Find parts of the packet and check sizes */
if (len < 23)
{
- too_small:
bgp_error(conn, 1, 2, len, 2);
return;
}
withdrawn = pkt + 21;
withdrawn_len = get_u16(pkt + 19);
if (withdrawn_len + 23 > len)
- goto too_small;
+ {
+ malformed:
+ bgp_error(conn, 3, 1, len, 0);
+ return;
+ }
attrs = withdrawn + withdrawn_len + 2;
attr_len = get_u16(attrs - 2);
if (withdrawn_len + attr_len + 23 > len)
- goto too_small;
+ goto malformed;
nlri = attrs + attr_len;
nlri_len = len - withdrawn_len - attr_len - 23;
if (!attr_len && nlri_len)
- goto too_small;
+ goto malformed;
DBG("Sizes: withdrawn=%d, attrs=%d, NLRI=%d\n", withdrawn_len, attr_len, nlri_len);
/* Withdraw routes */
while (withdrawn_len)
{
DECODE_PREFIX(withdrawn, withdrawn_len);
- DBG("Withdraw %I/%d\n", n.n.prefix, n.n.pxlen);
+ DBG("Withdraw %I/%d\n", prefix, pxlen);
+ if (n = net_find(bgp->p.table, prefix, pxlen))
+ rte_update(bgp->p.table, n, &bgp->p, NULL);
}
if (nlri_len)
{
-#if 0
rta *a = bgp_decode_attrs(conn, attrs, attr_len, bgp_linpool);
- if (a)
-#endif
+ if (!a)
+ return;
+ while (nlri_len)
{
- while (nlri_len)
- {
- DECODE_PREFIX(nlri, nlri_len);
- DBG("Add %I/%d\n", n.n.prefix, n.n.pxlen);
- }
+ rte *e;
+ DECODE_PREFIX(nlri, nlri_len); /* FIXME: Uncache rta ! */
+ DBG("Add %I/%d\n", prefix, pxlen);
+ e = rte_get_temp(a);
+ n = net_get(bgp->p.table, prefix, pxlen);
+ e->net = n;
+ e->pflags = 0;
+ rte_update(bgp->p.table, n, &bgp->p, e);
}
lp_flush(bgp_linpool);
+ rta_free(a);
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-02 03:24:10 +0200