Merge pull request #9318 from Prerana-GB/ibgp_knob

bgp: BGP knob for faster convergence of bgp sessions

7 files changed, 608 insertions, 2 deletions

diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index b62a42a4f6..0f2926d060 100644
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -2196,7 +2196,8 @@ void bgp_fsm_nht_update(struct peer *peer, bool has_valid_nexthops)
 	case OpenConfirm:
 	case Established:
 		if (!has_valid_nexthops
-		    && (peer->gtsm_hops == BGP_GTSM_HOPS_CONNECTED))
+		    && (peer->gtsm_hops == BGP_GTSM_HOPS_CONNECTED
+			|| peer->bgp->fast_convergence))
 			BGP_EVENT_ADD(peer, TCP_fatal_error);
 	case Clearing:
 	case Deleted:
diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index dcf0fe8469..9a1453b937 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -4190,6 +4190,28 @@ DEFUN (neighbor_remote_as,
 	return peer_remote_as_vty(vty, argv[idx_peer]->arg,
 				  argv[idx_remote_as]->arg);
 }
+/* Enable fast convergence of bgp sessions. If this is enabled, bgp
+ * sessions do not wait for hold timer expiry to bring down the sessions
+ * when nexthop becomes unreachable
+ */
+DEFUN(bgp_fast_convergence, bgp_fast_convergence_cmd, "bgp fast-convergence",
+      BGP_STR "Fast convergence for bgp sessions\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+	bgp->fast_convergence = true;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_bgp_fast_convergence, no_bgp_fast_convergence_cmd,
+      "no bgp fast-convergence",
+      NO_STR BGP_STR "Fast convergence for bgp sessions\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+	bgp->fast_convergence = false;
+
+	return CMD_SUCCESS;
+}
 
 static int peer_conf_interface_get(struct vty *vty, const char *conf_if,
 				   int v6only,
@@ -17198,6 +17220,9 @@ int bgp_config_write(struct vty *vty)
 		if (CHECK_FLAG(bgp->flags, BGP_FLAG_SHUTDOWN))
 			vty_out(vty, " bgp shutdown\n");
 
+		if (bgp->fast_convergence)
+			vty_out(vty, " bgp fast-convergence\n");
+
 		if (bgp->srv6_enabled) {
 			vty_frame(vty, " !\n segment-routing srv6\n");
 			if (strlen(bgp->srv6_locator_name))
@@ -17463,6 +17488,10 @@ void bgp_vty_init(void)
 	install_element(CONFIG_NODE, &bgp_set_route_map_delay_timer_cmd);
 	install_element(CONFIG_NODE, &no_bgp_set_route_map_delay_timer_cmd);
 
+	/* bgp fast-convergence command */
+	install_element(BGP_NODE, &bgp_fast_convergence_cmd);
+	install_element(BGP_NODE, &no_bgp_fast_convergence_cmd);
+
 	/* global bgp update-delay command */
 	install_element(CONFIG_NODE, &bgp_global_update_delay_cmd);
 	install_element(CONFIG_NODE, &no_bgp_global_update_delay_cmd);
diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index 3d10771bcb..cea7fb4c85 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -3166,7 +3166,7 @@ static struct bgp *bgp_create(as_t *as, const char *name,
 	bgp->reject_as_sets = false;
 	bgp->condition_check_period = DEFAULT_CONDITIONAL_ROUTES_POLL_TIME;
 	bgp_addpath_init_bgp_data(&bgp->tx_addpath);
-
+	bgp->fast_convergence = false;
 	bgp->as = *as;
 
 #ifdef ENABLE_BGP_VNC
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 62782f6040..dc8677d3a1 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -749,6 +749,8 @@ struct bgp {
 	/* Process Queue for handling routes */
 	struct work_queue *process_queue;
 
+	bool fast_convergence;
+
 	/* BGP Conditional advertisement */
 	uint32_t condition_check_period;
 	uint32_t condition_filter_count;
diff --git a/doc/user/bgp.rst b/doc/user/bgp.rst
index ad9e32853d..2383906150 100644
--- a/doc/user/bgp.rst
+++ b/doc/user/bgp.rst
@@ -4354,3 +4354,35 @@ Show command json output:
 .. [bgp-route-osci-cond] McPherson, D. and Gill, V. and Walton, D., "Border Gateway Protocol (BGP) Persistent Route Oscillation Condition", IETF RFC3345
 .. [stable-flexible-ibgp] Flavel, A. and M. Roughan, "Stable and flexible iBGP", ACM SIGCOMM 2009
 .. [ibgp-correctness] Griffin, T. and G. Wilfong, "On the correctness of IBGP configuration", ACM SIGCOMM 2002
+
+.. _bgp-fast-convergence:
+
+BGP fast-convergence support
+============================
+Whenever BGP peer address becomes unreachable we must bring down the BGP
+session immediately. Currently only single-hop EBGP sessions are brought 
+down immediately.IBGP and multi-hop EBGP sessions wait for hold-timer 
+expiry to bring down the sessions.
+
+This new configuration option helps user to teardown BGP sessions immediately
+whenever peer becomes unreachable.
+
+.. clicmd:: bgp fast-convergence
+
+This configuration is available at the bgp level. When enabled, configuration
+is applied to all the neighbors configured in that bgp instance.
+
+.. code-block:: frr
+
+   router bgp 64496
+    neighbor 10.0.0.2 remote-as 64496
+    neighbor fd00::2 remote-as 64496
+    bgp fast-convergence
+   !
+   address-family ipv4 unicast
+    redistribute static
+   exit-address-family
+   !
+   address-family ipv6 unicast
+    neighbor fd00::2 activate
+   exit-address-family
diff --git a/tests/topotests/bgp_ecmp_topo3/ibgp_ecmp_topo3.json b/tests/topotests/bgp_ecmp_topo3/ibgp_ecmp_topo3.json
new file mode 100644
index 0000000000..b01f9023b0
--- /dev/null
+++ b/tests/topotests/bgp_ecmp_topo3/ibgp_ecmp_topo3.json
@@ -0,0 +1,232 @@
+{
+    "address_types": [
+        "ipv4",
+        "ipv6"
+    ],
+    "ipv4base": "10.0.0.0",
+    "ipv4mask": 24,
+    "ipv6base": "fd00::",
+    "ipv6mask": 64,
+    "link_ip_start": {
+        "ipv4": "10.0.0.0",
+        "v4mask": 24,
+        "ipv6": "fd00::",
+        "v6mask": 64
+    },
+    "lo_prefix": {
+        "ipv4": "1.0.",
+        "v4mask": 32,
+        "ipv6": "2001:DB8:F::",
+        "v6mask": 128
+    },
+    "routers": {
+        "r1": {
+            "links": {
+                "lo": {
+                    "ipv4": "auto",
+                    "ipv6": "auto",
+                    "type": "loopback"
+                },
+                "r2-link1": {
+                    "ipv4": "auto",
+                    "ipv6": "auto"
+                }
+            },
+            "bgp": {
+                "local_as": "100",
+                "address_family": {
+                    "ipv4": {
+                        "unicast": {
+                            "neighbor": {
+                                "r2": {
+                                    "dest_link": {
+                                        "r1-link1": {}
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "ipv6": {
+                        "unicast": {
+                            "neighbor": {
+                                "r2": {
+                                    "dest_link": {
+                                        "r1-link1": {}
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
+        "r2": {
+            "links": {
+                "lo": {
+                    "ipv4": "auto",
+                    "ipv6": "auto",
+                    "type": "loopback"
+                },
+                "r1-link1": {
+                    "ipv4": "auto",
+                    "ipv6": "auto"
+                },
+                "r3-link1": {
+                    "ipv4": "auto",
+                    "ipv6": "auto"
+                },
+                "r3-link2": {
+                    "ipv4": "auto",
+                    "ipv6": "auto"
+                }
+            },
+            "bgp": {
+                "local_as": "100",
+                "address_family": {
+                    "ipv4": {
+                        "unicast": {
+                            "neighbor": {
+                                "r1": {
+                                    "dest_link": {
+                                        "r2-link1": {}
+                                    }
+                                },
+                                "r3": {
+                                    "dest_link": {
+                                        "r2-link1": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180,
+                                            "next_hop_self": true
+                                        },
+                                        "r2-link2": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180,
+                                            "next_hop_self": true
+                                        }
+                                    }
+                                }
+                            },
+                            "redistribute": [
+                                {
+                                    "redist_type": "static"
+                                }
+                            ]
+                        }
+                    },
+                    "ipv6": {
+                        "unicast": {
+                            "neighbor": {
+                                "r1": {
+                                    "dest_link": {
+                                        "r2-link1": {}
+                                    }
+                                },
+                                "r3": {
+                                    "dest_link": {
+                                        "r2-link1": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180,
+                                            "next_hop_self": true
+                                        },
+                                        "r2-link2": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180,
+                                            "next_hop_self": true
+                                        }
+                                    }
+                                }
+                            },
+                            "redistribute": [
+                                {
+                                    "redist_type": "static"
+                                }
+                            ]
+                        }
+                    }
+                }
+            }
+        },
+        "r3": {
+            "links": {
+                "lo": {
+                    "ipv4": "auto",
+                    "ipv6": "auto",
+                    "type": "loopback"
+                },
+                "r2-link1": {
+                    "ipv4": "auto",
+                    "ipv6": "auto"
+                },
+                "r2-link2": {
+                    "ipv4": "auto",
+                    "ipv6": "auto"
+                }
+            },
+            "route_maps": {
+                "rmap_global": [{
+                    "action": "permit",
+                    "set": {
+                        "ipv6": {
+                            "nexthop": "prefer-global"
+                        }
+                    }
+                }]
+            },
+            "bgp": {
+                "local_as": "100",
+                "address_family": {
+                    "ipv4": {
+                        "unicast": {
+                            "maximum_paths": {
+                                "ibgp": 2
+                            },
+                            "neighbor": {
+                                "r2": {
+                                    "dest_link": {
+                                        "r3-link1": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180
+                                        },
+                                        "r3-link2": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "ipv6": {
+                        "unicast": {
+                            "maximum_paths": {
+                                "ibgp": 2
+                            },
+                            "neighbor": {
+                                "r2": {
+                                    "dest_link": {
+                                        "r3-link1": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180,
+                                            "route_maps": [{
+                                                "name": "rmap_global",
+                                                "direction": "in"
+                                            }]
+                                        },
+                                        "r3-link2": {
+                                            "keepalivetimer": 60,
+                                            "holddowntimer": 180,
+                                            "route_maps": [{
+                                                "name": "rmap_global",
+                                                "direction": "in"
+                                            }]
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/tests/topotests/bgp_ecmp_topo3/test_ibgp_ecmp_topo3.py b/tests/topotests/bgp_ecmp_topo3/test_ibgp_ecmp_topo3.py
new file mode 100644
index 0000000000..5f3ac4e716
--- /dev/null
+++ b/tests/topotests/bgp_ecmp_topo3/test_ibgp_ecmp_topo3.py
@@ -0,0 +1,310 @@
+#!/usr/bin/env python
+
+#
+# Copyright (c) 2019 by VMware, Inc. ("VMware")
+# Used Copyright (c) 2018 by Network Device Education Foundation, Inc.
+# ("NetDEF") in this file.
+#
+# Permission to use, copy, modify, and/or distribute this software
+# for any purpose with or without fee is hereby granted, provided
+# that the above copyright notice and this permission notice appear
+# in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND VMWARE DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL VMWARE BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
+# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+# OF THIS SOFTWARE.
+#
+
+
+"""
+Following tests are covered to test ecmp functionality on iBGP.
+1. Verify bgp fast-convergence functionality
+"""
+import os
+import sys
+import time
+import json
+import pytest
+from time import sleep
+
+# Save the Current Working Directory to find configuration files.
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+sys.path.append(os.path.join(CWD, "../../"))
+
+# pylint: disable=C0413
+# Import topogen and topotest helpers
+from lib.topogen import Topogen, get_topogen
+from mininet.topo import Topo
+
+from lib.common_config import (
+    start_topology,
+    write_test_header,
+    write_test_footer,
+    verify_rib,
+    create_static_routes,
+    check_address_types,
+    interface_status,
+    reset_config_on_routers,
+    required_linux_kernel_version,
+    shutdown_bringup_interface,
+    apply_raw_config,
+)
+from lib.topolog import logger
+from lib.bgp import verify_bgp_convergence, create_router_bgp, clear_bgp
+from lib.topojson import build_topo_from_json, build_config_from_json
+
+
+pytestmark = [pytest.mark.bgpd, pytest.mark.staticd]
+
+
+# Reading the data from JSON File for topology and configuration creation
+jsonFile = "{}/ibgp_ecmp_topo3.json".format(CWD)
+
+try:
+    with open(jsonFile, "r") as topoJson:
+        topo = json.load(topoJson)
+except IOError:
+    assert False, "Could not read file {}".format(jsonFile)
+
+# Global variables
+NEXT_HOPS = {"ipv4": [], "ipv6": []}
+NETWORK = {"ipv4": "192.168.1.10/32", "ipv6": "fd00:0:0:1::10/128"}
+NEXT_HOP_IP = {"ipv4": "10.0.0.1", "ipv6": "fd00::1"}
+BGP_CONVERGENCE = False
+
+
+class CreateTopo(Topo):
+    """
+    Test topology builder.
+
+    * `Topo`: Topology object
+    """
+
+    def build(self, *_args, **_opts):
+        """Build function."""
+        tgen = get_topogen(self)
+
+        # Building topology from json file
+        build_topo_from_json(tgen, topo)
+
+
+def setup_module(mod):
+    """
+    Sets up the pytest environment.
+
+    * `mod`: module name
+    """
+    global NEXT_HOPS, INTF_LIST_R3, INTF_LIST_R2, TEST_STATIC
+    global ADDR_TYPES
+
+    testsuite_run_time = time.asctime(time.localtime(time.time()))
+    logger.info("Testsuite start time: {}".format(testsuite_run_time))
+    logger.info("=" * 40)
+
+    logger.info("Running setup_module to create topology")
+
+    # This function initiates the topology build with Topogen...
+    tgen = Topogen(CreateTopo, mod.__name__)
+
+    # Starting topology, create tmp files which are loaded to routers
+    #  to start deamons and then start routers
+    start_topology(tgen)
+
+    # Creating configuration from JSON
+    build_config_from_json(tgen, topo)
+
+    # Don't run this test if we have any failure.
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    # Api call verify whether BGP is converged
+    ADDR_TYPES = check_address_types()
+
+    BGP_CONVERGENCE = verify_bgp_convergence(tgen, topo)
+    assert BGP_CONVERGENCE is True, "setup_module :Failed \n Error:" " {}".format(
+        BGP_CONVERGENCE
+    )
+
+    # STATIC_ROUTE = True
+    logger.info("Running setup_module() done")
+
+
+def teardown_module():
+    """
+    Teardown the pytest environment.
+
+    * `mod`: module name
+    """
+
+    logger.info("Running teardown_module to delete topology")
+
+    tgen = get_topogen()
+
+    # Stop toplogy and Remove tmp files
+    tgen.stop_topology()
+
+
+def static_or_nw(tgen, topo, tc_name, test_type, dut):
+
+    if test_type == "redist_static":
+        input_dict_static = {
+            dut: {
+                "static_routes": [
+                    {"network": NETWORK["ipv4"], "next_hop": NEXT_HOP_IP["ipv4"]},
+                    {"network": NETWORK["ipv6"], "next_hop": NEXT_HOP_IP["ipv6"]},
+                ]
+            }
+        }
+        logger.info("Configuring static route on router %s", dut)
+        result = create_static_routes(tgen, input_dict_static)
+        assert result is True, "Testcase {} : Failed \n Error: {}".format(
+            tc_name, result
+        )
+
+        input_dict_2 = {
+            dut: {
+                "bgp": {
+                    "address_family": {
+                        "ipv4": {
+                            "unicast": {"redistribute": [{"redist_type": "static"}]}
+                        },
+                        "ipv6": {
+                            "unicast": {"redistribute": [{"redist_type": "static"}]}
+                        },
+                    }
+                }
+            }
+        }
+
+        logger.info("Configuring redistribute static route on router %s", dut)
+        result = create_router_bgp(tgen, topo, input_dict_2)
+        assert result is True, "Testcase {} : Failed \n Error: {}".format(
+            tc_name, result
+        )
+
+    elif test_type == "advertise_nw":
+        input_dict_nw = {
+            dut: {
+                "bgp": {
+                    "address_family": {
+                        "ipv4": {
+                            "unicast": {
+                                "advertise_networks": [{"network": NETWORK["ipv4"]}]
+                            }
+                        },
+                        "ipv6": {
+                            "unicast": {
+                                "advertise_networks": [{"network": NETWORK["ipv6"]}]
+                            }
+                        },
+                    }
+                }
+            }
+        }
+
+        logger.info(
+            "Advertising networks %s %s from router %s",
+            NETWORK["ipv4"],
+            NETWORK["ipv6"],
+            dut,
+        )
+        result = create_router_bgp(tgen, topo, input_dict_nw)
+        assert result is True, "Testcase {} : Failed \n Error: {}".format(
+            tc_name, result
+        )
+
+
+@pytest.mark.parametrize("test_type", ["redist_static"])
+def test_ecmp_fast_convergence(request, test_type):
+    """This test is to verify bgp fast-convergence cli functionality"""
+
+    tc_name = request.node.name
+    write_test_header(tc_name)
+    tgen = get_topogen()
+
+    # Verifying RIB routes
+    dut = "r3"
+    protocol = "bgp"
+
+    reset_config_on_routers(tgen)
+    static_or_nw(tgen, topo, tc_name, test_type, "r2")
+
+    for addr_type in ADDR_TYPES:
+        input_dict = {"r3": {"static_routes": [{"network": NETWORK[addr_type]}]}}
+
+        logger.info("Verifying %s routes on r3", addr_type)
+        result = verify_rib(
+            tgen,
+            addr_type,
+            dut,
+            input_dict,
+            protocol=protocol,
+        )
+        assert result is True, "Testcase {} : Failed \n Error: {}".format(
+            tc_name, result
+        )
+
+    intf1 = topo["routers"]["r2"]["links"]["r3-link1"]["interface"]
+    intf2 = topo["routers"]["r2"]["links"]["r3-link2"]["interface"]
+
+    logger.info("Shutdown one of the link b/w r2 and r3")
+    shutdown_bringup_interface(tgen, "r2", intf1, False)
+
+    logger.info("Verify bgp neighbors are still up")
+    result = verify_bgp_convergence(tgen, topo)
+    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)
+
+    logger.info("Shutdown another link b/w r2 and r3")
+    shutdown_bringup_interface(tgen, "r2", intf2, False)
+
+    logger.info("Wait for 10 sec and make sure bgp neighbors are still up")
+    sleep(10)
+    result = verify_bgp_convergence(tgen, topo)
+    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)
+
+    logger.info("No shut links b/w r2 and r3")
+    shutdown_bringup_interface(tgen, "r2", intf1, True)
+    shutdown_bringup_interface(tgen, "r2", intf2, True)
+
+    logger.info("Enable bgp fast-convergence cli")
+    raw_config = {
+       "r2": {
+          "raw_config": [
+            "router bgp {}".format(topo["routers"]["r2"]["bgp"]["local_as"]),
+            "bgp fast-convergence",
+          ]
+       }
+    }
+    result = apply_raw_config(tgen, raw_config)
+    assert result is True, "Testcase {} : Failed Error: {}".format(tc_name, result)
+
+    logger.info("Shutdown one link b/w r2 and r3")
+    shutdown_bringup_interface(tgen, "r2", intf1, False)
+
+    logger.info("Verify bgp neighbors goes down immediately")
+    result = verify_bgp_convergence(tgen, topo, dut="r2", expected=False)
+    assert result is not True, "Testcase {} : Failed \n Error: {}".format(
+        tc_name, result
+    )
+
+    logger.info("Shutdown second link b/w r2 and r3")
+    shutdown_bringup_interface(tgen, "r2", intf2, False)
+
+    logger.info("Verify bgp neighbors goes down immediately")
+    result = verify_bgp_convergence(tgen, topo, dut="r2", expected=False)
+    assert result is not True, "Testcase {} : Failed \n Error: {}".format(
+        tc_name, result
+    )
+
+    write_test_footer(tc_name)
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))