ospfd: add support for suppress_fa

This command will trigger the OSPF forwarding address suppression in
translated type-5 LSAs, causing a NSSA ABR to use 0.0.0.0 as a forwarding
address instead of copying the address from the type-7 LSA

Example: In a topology like: R1 --- R2(ABR) --- R3(ASBR)

R3 is announcing a type-7 LSA that is translated to type-5 by the R2 ABR.
The forwarding address in the type-5 is by default copied from the type-7

    r1# sh ip os da external

                    AS External Link States

      LS age: 6
      Options: 0x2  : *|-|-|-|-|-|E|-
      LS Flags: 0x6
      LS Type: AS-external-LSA
      Link State ID: 3.3.3.3 (External Network Number)
      Advertising Router: 10.0.25.2
      LS Seq Number: 80000001
      Checksum: 0xcf99
      Length: 36

      Network Mask: /32
            Metric Type: 2 (Larger than any link state path)
            TOS: 0
            Metric: 20
            Forward Address: 10.0.23.3    <--- address copied from type-7 lsa
            External Route Tag: 0

    r2# sh ip os database

                    NSSA-external Link States (Area 0.0.0.1 [NSSA])

    Link ID         ADV Router      Age  Seq#       CkSum  Route
    3.3.3.3         10.0.23.3          8 0x80000001 0x431d E2 3.3.3.3/32 [0x0]

                    AS External Link States

    Link ID         ADV Router      Age  Seq#       CkSum  Route
    3.3.3.3         10.0.25.2          0 0x80000001 0xcf99 E2 3.3.3.3/32 [0x0]

    r2# conf t
    r2(config)# router ospf
    r2(config-router)# area 1 nssa suppress-fa
    r2(config-router)# exit
    r2(config)# exit

    r2# sh ip os database

                    NSSA-external Link States (Area 0.0.0.1 [NSSA])

    Link ID         ADV Router      Age  Seq#       CkSum  Route
    3.3.3.3         10.0.23.3         66 0x80000001 0x431d E2 3.3.3.3/32 [0x0]

                    AS External Link States

    Link ID         ADV Router      Age  Seq#       CkSum  Route
    3.3.3.3         10.0.25.2         16 0x80000002 0x0983 E2 3.3.3.3/32 [0x0]

    r1# sh ip os da external

           OSPF Router with ID (11.11.11.11)

                    AS External Link States

      LS age: 34
      Options: 0x2  : *|-|-|-|-|-|E|-
      LS Flags: 0x6
      LS Type: AS-external-LSA
      Link State ID: 3.3.3.3 (External Network Number)
      Advertising Router: 10.0.25.2
      LS Seq Number: 80000002
      Checksum: 0x0983
      Length: 36

      Network Mask: /32
            Metric Type: 2 (Larger than any link state path)
            TOS: 0
            Metric: 20
            Forward Address: 0.0.0.0       <--- address set to 0
            External Route Tag: 0

    r2# conf t
    r2(config)# router ospf
    r2(config-router)# no area 1 nssa suppress-fa
    r2(config-router)# exit

    r1# sh ip os da external

           OSPF Router with ID (11.11.11.11)

                    AS External Link States

      LS age: 1
      Options: 0x2  : *|-|-|-|-|-|E|-
      LS Flags: 0x6
      LS Type: AS-external-LSA
      Link State ID: 3.3.3.3 (External Network Number)
      Advertising Router: 10.0.25.2
      LS Seq Number: 80000003
      Checksum: 0xcb9b
      Length: 36
      Network Mask: /32
            Metric Type: 2 (Larger than any link state path)
            TOS: 0
            Metric: 20
            Forward Address: 0.0.0.0       <--- address set to 0
            External Route Tag: 0

    r2# conf t
    r2(config)# router ospf
    r2(config-router)# no area 1 nssa suppress-fa
    r2(config-router)# exit

    r1# sh ip os da external

           OSPF Router with ID (11.11.11.11)

                    AS External Link States

      LS age: 1
      Options: 0x2  : *|-|-|-|-|-|E|-
      LS Flags: 0x6
      LS Type: AS-external-LSA
      Link State ID: 3.3.3.3 (External Network Number)
      Advertising Router: 10.0.25.2
      LS Seq Number: 80000003
      Checksum: 0xcb9b
      Length: 36

      Network Mask: /32
            Metric Type: 2 (Larger than any link state path)
            TOS: 0
            Metric: 20
            Forward Address: 10.0.23.3    <--- address copied from type-7 lsa
            External Route Tag: 0

Signed-off-by: ckishimo <carles.kishimoto@gmail.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/ospfd/ospf_vty.c b/ospfd/ospf_vty.c
index e6835ffc72..d634853b3e 100644
--- a/ospfd/ospf_vty.c
+++ b/ospfd/ospf_vty.c
@@ -1574,6 +1574,58 @@ DEFUN (ospf_area_nssa,
 	return ospf_area_nssa_cmd_handler(vty, argc, argv, 0, 0);
 }
 
+DEFUN(ospf_area_nssa_suppress_fa, ospf_area_nssa_suppress_fa_cmd,
+      "area <A.B.C.D|(0-4294967295)> nssa suppress-fa",
+      "OSPF area parameters\n"
+      "OSPF area ID in IP address format\n"
+      "OSPF area ID as a decimal value\n"
+      "Configure OSPF area as nssa\n"
+      "Suppress forwarding address\n")
+{
+	int idx_ipv4_number = 1;
+	struct in_addr area_id;
+	int format;
+
+	VTY_DECLVAR_INSTANCE_CONTEXT(ospf, ospf);
+	VTY_GET_OSPF_AREA_ID_NO_BB("NSSA", area_id, format,
+				   argv[idx_ipv4_number]->arg);
+
+	ospf_area_display_format_set(ospf, ospf_area_get(ospf, area_id),
+				     format);
+	ospf_area_nssa_suppress_fa_set(ospf, area_id);
+
+	ospf_schedule_abr_task(ospf);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_ospf_area_nssa_suppress_fa, no_ospf_area_nssa_suppress_fa_cmd,
+      "no area <A.B.C.D|(0-4294967295)> nssa suppress-fa",
+      NO_STR
+      "OSPF area parameters\n"
+      "OSPF area ID in IP address format\n"
+      "OSPF area ID as a decimal value\n"
+      "Configure OSPF area as nssa\n"
+      "Suppress forwarding address\n")
+{
+	int idx_ipv4_number = 2;
+	struct in_addr area_id;
+	int format;
+
+	VTY_DECLVAR_INSTANCE_CONTEXT(ospf, ospf);
+
+	VTY_GET_OSPF_AREA_ID_NO_BB("nssa", area_id, format,
+				   argv[idx_ipv4_number]->arg);
+
+	ospf_area_display_format_set(ospf, ospf_area_get(ospf, area_id),
+				     format);
+	ospf_area_nssa_suppress_fa_unset(ospf, area_id);
+
+	ospf_schedule_abr_task(ospf);
+
+	return CMD_SUCCESS;
+}
+
 DEFUN (ospf_area_nssa_no_summary,
        ospf_area_nssa_no_summary_cmd,
        "area <A.B.C.D|(0-4294967295)> nssa no-summary",
@@ -11823,6 +11875,10 @@ static int config_write_ospf_area(struct vty *vty, struct ospf *ospf)
 					vty_out(vty,
 						" area %s nssa no-summary\n",
 						buf);
+				if (area->suppress_fa)
+					vty_out(vty,
+						" area %s nssa suppress-fa\n",
+						buf);
 			}
 
 			if (area->default_cost != 1)
@@ -12684,6 +12740,8 @@ void ospf_vty_init(void)
 	install_element(OSPF_NODE, &ospf_area_nssa_translate_cmd);
 	install_element(OSPF_NODE, &ospf_area_nssa_no_summary_cmd);
 	install_element(OSPF_NODE, &no_ospf_area_nssa_no_summary_cmd);
+	install_element(OSPF_NODE, &ospf_area_nssa_suppress_fa_cmd);
+	install_element(OSPF_NODE, &no_ospf_area_nssa_suppress_fa_cmd);
 	install_element(OSPF_NODE, &no_ospf_area_nssa_cmd);
 
 	install_element(OSPF_NODE, &ospf_area_default_cost_cmd);