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>

1 files changed, 113 insertions, 0 deletions

diff --git a/pbrd/pbr_nht.h b/pbrd/pbr_nht.h
new file mode 100644
index 000000000..2508f49e4
--- /dev/null
+++ b/pbrd/pbr_nht.h
@@ -0,0 +1,113 @@
+/*
+ * PBR-nht Header
+ * Copyright (C) 2018 Cumulus Networks, Inc.
+ *               Donald Sharp
+ *
+ * FRR is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * FRR is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef __PBR_NHT_H__
+#define __PBR_NHT_H__
+
+#include <lib/zclient.h>
+#include <lib/nexthop_group.h>
+
+struct pbr_nexthop_group_cache {
+	char name[PBR_MAP_NAMELEN];
+
+	uint32_t table_id;
+
+	struct hash *nhh;
+
+	/*
+	 * If all nexthops are considered valid
+	 */
+	bool valid;
+
+	bool installed;
+};
+
+struct pbr_nexthop_cache {
+	struct pbr_nexthop_group_cache *parent;
+
+	struct nexthop nexthop;
+
+	bool valid;
+};
+
+extern void pbr_nht_write_table_range(struct vty *vty);
+#define PBR_NHT_DEFAULT_LOW_TABLEID 10000
+#define PBR_NHT_DEFAULT_HIGH_TABLEID 11000
+extern void pbr_nht_set_tableid_range(uint32_t low, uint32_t high);
+
+/*
+ * Get the next tableid to use for installation
+ */
+extern uint32_t pbr_nht_get_next_tableid(void);
+/*
+ * Get the next rule number to use for installation
+ */
+extern void pbr_nht_write_rule_range(struct vty *vty);
+
+#define PBR_NHT_DEFAULT_LOW_RULE 300
+#define PBR_NHT_DEFAULT_HIGH_RULE 1300
+extern void pbr_nht_set_rule_range(uint32_t low, uint32_t high);
+
+extern uint32_t pbr_nht_get_next_rule(uint32_t seqno);
+
+extern void pbr_nhgroup_add_cb(const char *name);
+extern void pbr_nhgroup_add_nexthop_cb(const struct nexthop_group_cmd *nhg,
+				       const struct nexthop *nhop);
+extern void pbr_nhgroup_del_nexthop_cb(const struct nexthop_group_cmd *nhg,
+				       const struct nexthop *nhop);
+extern void pbr_nhgroup_delete_cb(const char *name);
+
+extern bool pbr_nht_nexthop_valid(struct nexthop_group *nhg);
+extern bool pbr_nht_nexthop_group_valid(const char *name);
+
+extern void pbr_nht_add_group(const char *name);
+extern void pbr_nht_change_group(const char *name);
+extern void pbr_nht_delete_group(const char *name);
+
+extern void pbr_nht_add_individual_nexthop(const char *name, uint32_t seqno);
+extern void pbr_nht_delete_individual_nexthop(const char *name, uint32_t seqno);
+/*
+ * Given the tableid of the installed default
+ * route, find the nexthop-group associated with
+ * it, then find all pbr-maps that use it and
+ * install/delete them as well.
+ */
+extern void pbr_nht_route_installed_for_table(uint32_t table_id);
+extern void pbr_nht_route_removed_for_table(uint32_t table_id);
+
+/*
+ * Given the nexthop group name, lookup the associated
+ * tableid with it
+ */
+extern uint32_t pbr_nht_get_table(const char *name);
+
+extern bool pbr_nht_get_installed(const char *name);
+
+extern char *pbr_nht_nexthop_make_name(char *name, size_t l, uint32_t seqno,
+				       char *buffer);
+
+extern void pbr_nht_show_nexthop_group(struct vty *vty, const char *name);
+
+/*
+ * When we get a callback from zebra about a nexthop changing
+ */
+extern void pbr_nht_nexthop_update(struct zapi_route *nhr);
+
+extern void pbr_nht_init(void);
+#endif