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Diffstat (limited to 'proto/bgp/packets.c')
-rw-r--r--proto/bgp/packets.c158
1 files changed, 120 insertions, 38 deletions
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index 2e6f0b60..c18c6e42 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -12,6 +12,7 @@
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
+#include "nest/attrs.h"
#include "conf/conf.h"
#include "lib/unaligned.h"
#include "lib/socket.h"
@@ -30,33 +31,64 @@ bgp_create_notification(struct bgp_conn *conn, byte *buf)
return buf + 2 + conn->notify_size;
}
+#ifdef IPV6
+static byte *
+bgp_put_cap_ipv6(struct bgp_conn *conn UNUSED, byte *buf)
+{
+ *buf++ = 1; /* Capability 1: Multiprotocol extensions */
+ *buf++ = 4; /* Capability data length */
+ *buf++ = 0; /* We support AF IPv6 */
+ *buf++ = BGP_AF_IPV6;
+ *buf++ = 0; /* RFU */
+ *buf++ = 1; /* and SAFI 1 */
+ return buf;
+}
+#endif
+
+static byte *
+bgp_put_cap_as4(struct bgp_conn *conn, byte *buf)
+{
+ *buf++ = 65; /* Capability 65: Support for 4-octet AS number */
+ *buf++ = 4; /* Capability data length */
+ put_u32(buf, conn->bgp->local_as);
+ return buf + 4;
+}
+
static byte *
bgp_create_open(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
+ byte *cap;
+ int cap_len;
BGP_TRACE(D_PACKETS, "Sending OPEN(ver=%d,as=%d,hold=%d,id=%08x)",
BGP_VERSION, p->local_as, p->cf->hold_time, p->local_id);
buf[0] = BGP_VERSION;
- put_u16(buf+1, p->local_as);
+ put_u16(buf+1, (p->local_as < 0xFFFF) ? p->local_as : AS_TRANS);
put_u16(buf+3, p->cf->hold_time);
put_u32(buf+5, p->local_id);
-#ifndef IPV6
- buf[9] = 0; /* No optional parameters */
- return buf+10;
-#else
- buf += 9;
- *buf++ = 8; /* Optional params len */
- *buf++ = 2; /* Option: Capability list */
- *buf++ = 6; /* Option length */
- *buf++ = 1; /* Capability 1: Multiprotocol extensions */
- *buf++ = 4; /* Capability data length */
- *buf++ = 0; /* We support AF IPv6 */
- *buf++ = BGP_AF_IPV6;
- *buf++ = 0; /* RFU */
- *buf++ = 1; /* and SAFI 1 */
- return buf;
+ /* Skipped 3 B for length field and Capabilities parameter header */
+ cap = buf + 12;
+
+#ifdef IPV6
+ cap = bgp_put_cap_ipv6(conn, cap);
#endif
+ if (p->cf->enable_as4)
+ cap = bgp_put_cap_as4(conn, cap);
+
+ cap_len = cap - buf - 12;
+ if (cap_len > 0)
+ {
+ buf[9] = cap_len + 2; /* Optional params len */
+ buf[10] = 2; /* Option: Capability list */
+ buf[11] = cap_len; /* Option length */
+ return cap;
+ }
+ else
+ {
+ buf[9] = 0; /* No optional parameters */
+ return buf + 10;
+ }
}
static unsigned int
@@ -118,7 +150,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
continue;
}
DBG("Processing bucket %p\n", buck);
- a_size = bgp_encode_attrs(w+2, buck->eattrs, 1024);
+ a_size = bgp_encode_attrs(p, w+2, buck->eattrs, 1024);
put_u16(w, a_size);
w += a_size + 2;
r_size = bgp_encode_prefixes(p, w, buck, remains - a_size);
@@ -161,12 +193,12 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
if ((buck = p->withdraw_bucket) && !EMPTY_LIST(buck->prefixes))
{
DBG("Withdrawn routes:\n");
- tmp = bgp_attach_attr(&ea, bgp_linpool, BA_MP_UNREACH_NLRI, remains-8);
+ tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_UNREACH_NLRI, remains-8);
*tmp++ = 0;
*tmp++ = BGP_AF_IPV6;
*tmp++ = 1;
ea->attrs[0].u.ptr->length = bgp_encode_prefixes(p, tmp, buck, remains-11);
- size = bgp_encode_attrs(w, ea, remains);
+ size = bgp_encode_attrs(p, w, ea, remains);
w += size;
remains -= size;
}
@@ -183,10 +215,10 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
continue;
}
DBG("Processing bucket %p\n", buck);
- size = bgp_encode_attrs(w, buck->eattrs, 1024);
+ size = bgp_encode_attrs(p, w, buck->eattrs, 1024);
w += size;
remains -= size;
- tstart = tmp = bgp_attach_attr(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
+ tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
*tmp++ = 0;
*tmp++ = BGP_AF_IPV6;
*tmp++ = 1;
@@ -230,7 +262,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
*tmp++ = 0; /* No SNPA information */
tmp += bgp_encode_prefixes(p, tmp, buck, remains - (8+3+32+1));
ea->attrs[0].u.ptr->length = tmp - tstart;
- w += bgp_encode_attrs(w, ea, remains);
+ w += bgp_encode_attrs(p, w, ea, remains);
break;
}
}
@@ -353,9 +385,50 @@ bgp_tx(sock *sk)
;
}
+/* Capatibility negotiation as per RFC 2842 */
+
+void
+bgp_parse_capabilities(struct bgp_conn *conn, byte *opt, int len)
+{
+ struct bgp_proto *p = conn->bgp;
+ int cl;
+ u32 as;
+
+ while (len > 0)
+ {
+ if (len < 2 || len < 2 + opt[1])
+ goto err;
+
+ cl = opt[1];
+
+ switch (opt[0])
+ {
+ case 65:
+ if (cl != 4)
+ goto err;
+ p->as4_support = 1;
+ p->as4_session = p->cf->enable_as4;
+ if (p->as4_session)
+ conn->advertised_as = get_u32(opt + 2);
+ break;
+
+ /* We can safely ignore all other capabilities */
+ }
+ len -= 2 + cl;
+ opt += 2 + cl;
+ }
+ return;
+
+ err:
+ bgp_error(conn, 2, 0, NULL, 0);
+ return;
+}
+
static int
bgp_parse_options(struct bgp_conn *conn, byte *opt, int len)
{
+ int ol;
+
while (len > 0)
{
if (len < 2 || len < 2 + opt[1])
@@ -369,12 +442,14 @@ bgp_parse_options(struct bgp_conn *conn, byte *opt, int len)
DBG("\n");
}
#endif
+
+ ol = opt[1];
switch (opt[0])
{
case 2:
- /* Capatibility negotiation as per RFC 2842 */
- /* We can safely ignore all capabilities announced */
+ bgp_parse_capabilities(conn, opt + 2, ol);
break;
+
default:
/*
* BGP specs don't tell us to send which option
@@ -382,11 +457,11 @@ bgp_parse_options(struct bgp_conn *conn, byte *opt, int len)
* to do so. Also, capability negotiation with
* Cisco routers doesn't work without that.
*/
- bgp_error(conn, 2, 4, opt, opt[1]);
+ bgp_error(conn, 2, 4, opt, ol);
return 0;
}
- len -= 2 + opt[1];
- opt += 2 + opt[1];
+ len -= 2 + ol;
+ opt += 2 + ol;
}
return 0;
}
@@ -397,7 +472,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
struct bgp_conn *other;
struct bgp_proto *p = conn->bgp;
struct bgp_config *cf = p->cf;
- unsigned as, hold;
+ unsigned hold;
u32 id;
/* Check state */
@@ -409,20 +484,27 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
{ bgp_error(conn, 1, 2, pkt+16, 2); return; }
if (pkt[19] != BGP_VERSION)
{ bgp_error(conn, 2, 1, pkt+19, 1); return; } /* RFC 1771 says 16 bits, draft-09 tells to use 8 */
- as = get_u16(pkt+20);
+ conn->advertised_as = get_u16(pkt+20);
hold = get_u16(pkt+22);
id = get_u32(pkt+24);
- BGP_TRACE(D_PACKETS, "Got OPEN(as=%d,hold=%d,id=%08x)", as, hold, id);
- if (cf->remote_as && as != p->remote_as)
- { bgp_error(conn, 2, 2, pkt+20, -2); return; }
- if (hold > 0 && hold < 3)
- { bgp_error(conn, 2, 6, pkt+22, 2); return; }
- p->remote_id = id;
+ BGP_TRACE(D_PACKETS, "Got OPEN(as=%d,hold=%d,id=%08x)", conn->advertised_as, hold, id);
+
+ p->remote_id = id; // ???
if (bgp_parse_options(conn, pkt+29, pkt[28]))
return;
+
+ if (hold > 0 && hold < 3)
+ { bgp_error(conn, 2, 6, pkt+22, 2); return; }
+
if (!id || id == 0xffffffff || id == p->local_id)
{ bgp_error(conn, 2, 3, pkt+24, -4); return; }
+
+ if (conn->advertised_as != p->remote_as)
+ {
+ bgp_error(conn, 2, 2, (byte *) &(conn->advertised_as), -4); return;
+ }
+
/* Check the other connection */
other = (conn == &p->outgoing_conn) ? &p->incoming_conn : &p->outgoing_conn;
switch (other->state)
@@ -463,7 +545,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
else
conn->hold_time = p->cf->hold_time;
conn->keepalive_time = p->cf->keepalive_time ? : conn->hold_time / 3;
- p->remote_as = as;
+ // p->remote_as = conn->advertised_as;
p->remote_id = id;
DBG("BGP: Hold timer set to %d, keepalive to %d, AS to %d, ID to %x\n", conn->hold_time, conn->keepalive_time, p->remote_as, p->remote_id);
@@ -621,7 +703,7 @@ bgp_do_rx_update(struct bgp_conn *conn,
/* Create fake NEXT_HOP attribute */
if (len < 1 || (*x != 16 && *x != 32) || len < *x + 2)
goto bad;
- memcpy(bgp_attach_attr(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, 16), x+1, 16);
+ bgp_attach_attr_ip(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, x[1]);
len -= *x + 2;
x += *x + 1;
@@ -720,7 +802,7 @@ static struct {
{ 2, 4, "Unsupported optional parameter" },
{ 2, 5, "Authentication failure" },
{ 2, 6, "Unacceptable hold time" },
- { 2, 7, "Required capability missing" }, /* capability negotiation draft */
+ { 2, 7, "Required capability missing" }, /* [RFC3392] */
{ 3, 0, "Invalid UPDATE message" },
{ 3, 1, "Malformed attribute list" },
{ 3, 2, "Unrecognized well-known attribute" },
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 01:56:00 +0000