pbrd: Add PBR to FRR

This is an implementation of PBR for FRR.

This implemenation uses a combination of rules and
tables to determine how packets will flow.

PBR introduces a new concept of 'nexthop-groups' to
specify a group of nexthops that will be used for
ecmp.  Nexthop-groups are specified on the cli via:

nexthop-group DONNA
  nexthop 192.168.208.1
  nexthop 192.168.209.1
  nexthop 192.168.210.1
!

PBR sees the nexthop-group and installs these as a default
route with these nexthops starting at table 10000
robot# show pbr nexthop-groups
Nexthop-Group: DONNA Table: 10001 Valid: 1 Installed: 1
	Valid: 1  nexthop 192.168.209.1
	Valid: 1  nexthop 192.168.210.1
	Valid: 1  nexthop 192.168.208.1

I have also introduced the ability to specify a table
in a 'show ip route table XXX' to see the specified tables.

robot# show ip route table 10001
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR,
       > - selected route, * - FIB route

F>* 0.0.0.0/0 [0/0] via 192.168.208.1, enp0s8, 00:14:25
  *                 via 192.168.209.1, enp0s9, 00:14:25
  *                 via 192.168.210.1, enp0s10, 00:14:25

PBR tracks PBR-MAPS via the pbr-map command:

!
pbr-map EVA seq 10
  match src-ip 4.3.4.0/24
  set nexthop-group DONNA
!
pbr-map EVA seq 20
  match dst-ip 4.3.5.0/24
  set nexthop-group DONNA
!

pbr-maps can have 'match src-ip <prefix>' and 'match dst-ip <prefix>'
to affect decisions about incoming packets.  Additionally if you
only have one nexthop to use for a pbr-map you do not need
to setup a nexthop-group and can specify 'set nexthop XXXX'.

To apply the pbr-map to an incoming interface you do this:

interface enp0s10
 pbr-policy EVA
!

When a pbr-map is applied to interfaces it can be installed
into the kernel as a rule:

[sharpd@robot frr1]$ ip rule show
0:	from all lookup local
309:	from 4.3.4.0/24 iif enp0s10 lookup 10001
319:	from all to 4.3.5.0/24 iif enp0s10 lookup 10001
1000:	from all lookup [l3mdev-table]
32766:	from all lookup main
32767:	from all lookup default

[sharpd@robot frr1]$ ip route show table 10001
default proto pbr metric 20
	nexthop via 192.168.208.1 dev enp0s8 weight 1
	nexthop via 192.168.209.1 dev enp0s9 weight 1
	nexthop via 192.168.210.1 dev enp0s10 weight 1

The linux kernel now will use the rules and tables to properly
apply these policies.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: Don Slice <dslice@cumulusnetworks.com>
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

4 files changed, 8 insertions, 0 deletions

diff --git a/lib/command.c b/lib/command.c
index f244d67e86..2bff3b17a2 100644
--- a/lib/command.c
+++ b/lib/command.c
@@ -105,6 +105,7 @@ const char *node_names[] = {
 	"as list",		    // AS_LIST_NODE,
 	"community list",	   // COMMUNITY_LIST_NODE,
 	"routemap",		    // RMAP_NODE,
+	"pbr-map",		    // PBRMAP_NODE,
 	"smux",			    // SMUX_NODE,
 	"dump",			    // DUMP_NODE,
 	"forwarding",		    // FORWARDING_NODE,
@@ -1312,6 +1313,7 @@ void cmd_exit(struct vty *vty)
 	case ISIS_NODE:
 	case KEYCHAIN_NODE:
 	case RMAP_NODE:
+	case PBRMAP_NODE:
 	case VTY_NODE:
 		vty->node = CONFIG_NODE;
 		break;
@@ -1409,6 +1411,7 @@ DEFUN (config_end,
 	case BGP_EVPN_VNI_NODE:
 	case BGP_IPV6L_NODE:
 	case RMAP_NODE:
+	case PBRMAP_NODE:
 	case OSPF_NODE:
 	case OSPF6_NODE:
 	case LDP_NODE:
diff --git a/lib/command.h b/lib/command.h
index 8d88ea1902..4bb57c77a3 100644
--- a/lib/command.h
+++ b/lib/command.h
@@ -128,6 +128,7 @@ enum node_type {
 	AS_LIST_NODE,		 /* AS list node. */
 	COMMUNITY_LIST_NODE,     /* Community list node. */
 	RMAP_NODE,		 /* Route map node. */
+	PBRMAP_NODE,		 /* PBR map node. */
 	SMUX_NODE,		 /* SNMP configuration node. */
 	DUMP_NODE,		 /* Packet dump node. */
 	FORWARDING_NODE,	 /* IP forwarding node. */
diff --git a/lib/route_types.txt b/lib/route_types.txt
index 310a993c38..91eaf94d95 100644
--- a/lib/route_types.txt
+++ b/lib/route_types.txt
@@ -78,6 +78,7 @@ ZEBRA_ROUTE_BGP_DIRECT, bgp-direct, NULL,  'b', 0, 0, "BGP-Direct"
 ZEBRA_ROUTE_BGP_DIRECT_EXT, bgp-direct-to-nve-groups, NULL, 'e', 0, 0, "BGP2VNC"
 ZEBRA_ROUTE_BABEL,      babel,     babeld, 'A', 1, 1, "Babel"
 ZEBRA_ROUTE_SHARP,    sharp,     sharpd, 'D', 1, 1, "SHARP"
+ZEBRA_ROUTE_PBR,      pbr,       pbrd, 'F', 1, 1, "PBR"
 ZEBRA_ROUTE_ALL,        wildcard,  none,   '-', 0, 0, "-"
 
 
@@ -103,3 +104,4 @@ ZEBRA_ROUTE_LDP,    "Label Distribution Protocol (LDP)"
 ZEBRA_ROUTE_VNC_DIRECT,    "VNC direct (not via zebra) routes"
 ZEBRA_ROUTE_BABEL,  "Babel routing protocol (Babel)"
 ZEBRA_ROUTE_SHARP, "Super Happy Advanced Routing Protocol (sharpd)"
+ZEBRA_ROUTE_PBR, "Policy Based Routing (PBR)"
diff --git a/lib/vty.c b/lib/vty.c
index 9381c6e0fd..e8463da3d7 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -719,6 +719,7 @@ static void vty_end_config(struct vty *vty)
 	case BGP_EVPN_NODE:
 	case BGP_IPV6L_NODE:
 	case RMAP_NODE:
+	case PBRMAP_NODE:
 	case OSPF_NODE:
 	case OSPF6_NODE:
 	case LDP_NODE:
@@ -1115,6 +1116,7 @@ static void vty_stop_input(struct vty *vty)
 	case EIGRP_NODE:
 	case BGP_NODE:
 	case RMAP_NODE:
+	case PBRMAP_NODE:
 	case OSPF_NODE:
 	case OSPF6_NODE:
 	case LDP_NODE: