BGP: support for addpath TX

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>
Reviewed-by:   Donald Sharp <sharpd@cumulusnetworks.com>
Reviewed-by:   Vivek Venkataraman <vivek@cumulusnetworks.com

Ticket: CM-8014

This implements addpath TX with the first feature to use it
being "neighbor x.x.x.x addpath-tx-all-paths".

One change to show output is 'show ip bgp x.x.x.x'.  If no addpath-tx
features are configured for any peers then everything looks the same
as it is today in that "Advertised to" is at the top and refers to
which peers the bestpath was advertise to.

root@superm-redxp-05[quagga-stash5]# vtysh -c 'show ip bgp 1.1.1.1'
BGP routing table entry for 1.1.1.1/32
Paths: (6 available, best #6, table Default-IP-Routing-Table)
  Advertised to non peer-group peers:
  r1(10.0.0.1) r2(10.0.0.2) r3(10.0.0.3) r4(10.0.0.4) r5(10.0.0.5) r6(10.0.0.6) r8(10.0.0.8)
  Local, (Received from a RR-client)
    12.12.12.12 (metric 20) from r2(10.0.0.2) (10.0.0.2)
      Origin IGP, metric 0, localpref 100, valid, internal
      AddPath ID: RX 0, TX 8
      Last update: Fri Oct 30 18:26:44 2015
[snip]

but once you enable an addpath feature we must display "Advertised to" on a path-by-path basis:

superm-redxp-05# show ip bgp 1.1.1.1/32
BGP routing table entry for 1.1.1.1/32
Paths: (6 available, best #6, table Default-IP-Routing-Table)
  Local, (Received from a RR-client)
    12.12.12.12 (metric 20) from r2(10.0.0.2) (10.0.0.2)
      Origin IGP, metric 0, localpref 100, valid, internal
      AddPath ID: RX 0, TX 8
      Advertised to: r8(10.0.0.8)
      Last update: Fri Oct 30 18:26:44 2015

  Local, (Received from a RR-client)
    34.34.34.34 (metric 20) from r3(10.0.0.3) (10.0.0.3)
      Origin IGP, metric 0, localpref 100, valid, internal
      AddPath ID: RX 0, TX 7
      Advertised to: r8(10.0.0.8)
      Last update: Fri Oct 30 18:26:39 2015

  Local, (Received from a RR-client)
    56.56.56.56 (metric 20) from r6(10.0.0.6) (10.0.0.6)
      Origin IGP, metric 0, localpref 100, valid, internal
      AddPath ID: RX 0, TX 6
      Advertised to: r8(10.0.0.8)
      Last update: Fri Oct 30 18:26:39 2015

  Local, (Received from a RR-client)
    56.56.56.56 (metric 20) from r5(10.0.0.5) (10.0.0.5)
      Origin IGP, metric 0, localpref 100, valid, internal
      AddPath ID: RX 0, TX 5
      Advertised to: r8(10.0.0.8)
      Last update: Fri Oct 30 18:26:39 2015

  Local, (Received from a RR-client)
    34.34.34.34 (metric 20) from r4(10.0.0.4) (10.0.0.4)
      Origin IGP, metric 0, localpref 100, valid, internal
      AddPath ID: RX 0, TX 4
      Advertised to: r8(10.0.0.8)
      Last update: Fri Oct 30 18:26:39 2015

  Local, (Received from a RR-client)
    12.12.12.12 (metric 20) from r1(10.0.0.1) (10.0.0.1)
      Origin IGP, metric 0, localpref 100, valid, internal, best
      AddPath ID: RX 0, TX 3
      Advertised to: r1(10.0.0.1) r2(10.0.0.2) r3(10.0.0.3) r4(10.0.0.4) r5(10.0.0.5) r6(10.0.0.6) r8(10.0.0.8)
      Last update: Fri Oct 30 18:26:34 2015

superm-redxp-05#

1 files changed, 5 insertions, 4 deletions

diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index a846faf679..789422f640 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -196,9 +196,9 @@ extern bgp_size_t bgp_packet_attribute (struct bgp *bgp, struct peer *,
 					struct bpacket_attr_vec_arr *vecarr,
 					struct prefix *, afi_t, safi_t,
 					struct peer *, struct prefix_rd *,
-					u_char *);
+					u_char *, int, u_int32_t);
 extern void bgp_dump_routes_attr (struct stream *, struct attr *,
-				  struct prefix *);
+                                  struct prefix *);
 extern int attrhash_cmp (const void *, const void *);
 extern unsigned int attrhash_key_make (void *);
 extern void attr_show_all (struct vty *);
@@ -239,14 +239,15 @@ extern size_t bgp_packet_mpattr_start(struct stream *s, afi_t afi, safi_t safi,
 				      struct attr *attr);
 extern void bgp_packet_mpattr_prefix(struct stream *s, afi_t afi, safi_t safi,
 				     struct prefix *p, struct prefix_rd *prd,
-				     u_char *tag);
+				     u_char *tag, int addpath_encode,
+                                     u_int32_t addpath_tx_id);
 extern void bgp_packet_mpattr_end(struct stream *s, size_t sizep);
 
 extern size_t bgp_packet_mpunreach_start (struct stream *s, afi_t afi,
 					  safi_t safi);
 extern void bgp_packet_mpunreach_prefix (struct stream *s, struct prefix *p,
 			     afi_t afi, safi_t safi, struct prefix_rd *prd,
-			     u_char *tag);
+			     u_char *tag, int, u_int32_t);
 extern void bgp_packet_mpunreach_end (struct stream *s, size_t attrlen_pnt);
 
 static inline int