From cf31112f0d7618464097f71228f84bd534f1bc0f Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Sun, 3 Jan 2010 12:17:52 +0100
Subject: Implements MRTdump feature.

---
 proto/bgp/packets.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 93 insertions(+), 12 deletions(-)

(limited to 'proto/bgp/packets.c')

diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index 91b4792..03cc4ee 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -13,6 +13,7 @@
 #include "nest/protocol.h"
 #include "nest/route.h"
 #include "nest/attrs.h"
+#include "nest/mrtdump.h"
 #include "conf/conf.h"
 #include "lib/unaligned.h"
 #include "lib/socket.h"
@@ -23,6 +24,84 @@
 
 static struct rate_limit rl_rcv_update,  rl_snd_update;
 
+/*
+ * MRT Dump format is not semantically specified.
+ * We will use these values in appropriate fields:
+ *
+ * Local AS, Remote AS - configured AS numbers for given BGP instance.
+ * Local IP, Remote IP - IP addresses of the TCP connection (0 if no connection)
+ *
+ * We dump two kinds of MRT messages: STATE_CHANGE (for BGP state
+ * changes) and MESSAGE (for received BGP messages).
+ *
+ * STATE_CHANGE uses always AS4 variant, but MESSAGE uses AS4 variant
+ * only when AS4 session is established and even in that case MESSAGE
+ * does not use AS4 variant for initial OPEN message. This strange
+ * behavior is here for compatibility with Quagga and Bgpdump,
+ */
+
+static byte *
+mrt_put_bgp4_hdr(byte *buf, struct bgp_conn *conn, int as4)
+{
+  struct bgp_proto *p = conn->bgp;
+  ip_addr local_addr;
+
+  if (as4)
+    {
+      put_u32(buf+0, p->remote_as);
+      put_u32(buf+4, p->local_as);
+      buf+=8;
+    }
+  else
+    {
+      put_u16(buf+0, (p->remote_as <= 0xFFFF) ? p->remote_as : AS_TRANS);
+      put_u16(buf+2, (p->local_as <= 0xFFFF)  ? p->local_as  : AS_TRANS);
+      buf+=4;
+    }
+
+  put_u16(buf+0, p->neigh->iface->index);
+  put_u16(buf+2, BGP_AF);
+  buf+=4;
+  buf = ipa_put_addr(buf, conn->sk ? conn->sk->daddr : IPA_NONE);
+  buf = ipa_put_addr(buf, conn->sk ? conn->sk->saddr : IPA_NONE);
+
+  return buf;
+}
+
+static void
+mrt_dump_bgp_packet(struct bgp_conn *conn, byte *pkt, unsigned len)
+{
+  byte buf[BGP_MAX_PACKET_LENGTH + 128];
+  byte *bp = buf + MRTDUMP_HDR_LENGTH;
+  int as4 = conn->bgp->as4_session;
+
+  bp = mrt_put_bgp4_hdr(bp, conn, as4);
+  memcpy(bp, pkt, len);
+  bp += len;
+  mrt_dump_message(&conn->bgp->p, BGP4MP, as4 ? BGP4MP_MESSAGE_AS4 : BGP4MP_MESSAGE,
+		   buf, bp-buf);
+}
+
+static inline u16
+convert_state(unsigned state)
+{
+  /* Convert state from our BS_* values to values used in MRTDump */
+  return (state == BS_CLOSE) ? 1 : state + 1;
+}
+
+void
+mrt_dump_bgp_state_change(struct bgp_conn *conn, unsigned old, unsigned new)
+{
+  byte buf[128];
+  byte *bp = buf + MRTDUMP_HDR_LENGTH;
+
+  bp = mrt_put_bgp4_hdr(bp, conn, 1);
+  put_u16(bp+0, convert_state(old));
+  put_u16(bp+2, convert_state(new));
+  bp += 4;
+  mrt_dump_message(&conn->bgp->p, BGP4MP, BGP4MP_STATE_CHANGE_AS4, buf, bp-buf);
+}
+
 static byte *
 bgp_create_notification(struct bgp_conn *conn, byte *buf)
 {
@@ -403,13 +482,8 @@ bgp_create_route_refresh(struct bgp_conn *conn, byte *buf)
   struct bgp_proto *p = conn->bgp;
   BGP_TRACE(D_PACKETS, "Sending ROUTE-REFRESH");
 
-#ifdef IPV6
-  *buf++ = 0;		/* AFI IPv6 */
-  *buf++ = BGP_AF_IPV6;
-#else
-  *buf++ = 0;		/* AFI IPv4 */
-  *buf++ = BGP_AF_IPV4;
-#endif
+  *buf++ = 0;
+  *buf++ = BGP_AF;
   *buf++ = 0;		/* RFU */
   *buf++ = 1;		/* and SAFI 1 */
   return buf;
@@ -552,12 +626,13 @@ bgp_parse_capabilities(struct bgp_conn *conn, byte *opt, int len)
 
       switch (opt[0])
 	{
-	case 2:
+	case 2:	/* Route refresh capability, RFC 2918 */
 	  if (cl != 0)
 	    goto err;
 	  conn->peer_refresh_support = 1;
 	  break;
-	case 65:
+
+	case 65: /* AS4 capability, RFC 4893 */ 
 	  if (cl != 4)
 	    goto err;
 	  conn->peer_as4_support = 1;
@@ -709,7 +784,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
 
   bgp_schedule_packet(conn, PKT_KEEPALIVE);
   bgp_start_timer(conn->hold_timer, conn->hold_time);
-  conn->state = BS_OPENCONFIRM;
+  bgp_conn_enter_openconfirm_state(conn);
 }
 
 #define DECODE_PREFIX(pp, ll) do {		\
@@ -1160,8 +1235,14 @@ bgp_rx_route_refresh(struct bgp_conn *conn, byte *pkt, int len)
 static void
 bgp_rx_packet(struct bgp_conn *conn, byte *pkt, unsigned len)
 {
-  DBG("BGP: Got packet %02x (%d bytes)\n", pkt[18], len);
-  switch (pkt[18])
+  byte type = pkt[18];
+
+  DBG("BGP: Got packet %02x (%d bytes)\n", type, len);
+
+  if (conn->bgp->p.mrtdump & MD_MESSAGES)
+    mrt_dump_bgp_packet(conn, pkt, len);
+
+  switch (type)
     {
     case PKT_OPEN:		return bgp_rx_open(conn, pkt, len);
     case PKT_UPDATE:		return bgp_rx_update(conn, pkt, len);
-- 
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