Adding upstream version 8.4.4.upstream/8.4.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2218 insertions, 0 deletions

diff --git a/tools/frr-reload.py b/tools/frr-reload.py
new file mode 100755
index 0000000..db8a728
--- /dev/null
+++ b/tools/frr-reload.py
@@ -0,0 +1,2218 @@
+#!/usr/bin/env python3
+# Frr Reloader
+# Copyright (C) 2014 Cumulus Networks, Inc.
+#
+# This file is part of Frr.
+#
+# 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 Frr; see the file COPYING.  If not, write to the Free
+# Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+#  02111-1307, USA.
+#
+"""
+This program
+- reads a frr configuration text file
+- reads frr's current running configuration via "vtysh -c 'show running'"
+- compares the two configs and determines what commands to execute to
+  synchronize frr's running configuration with the configuation in the
+  text file
+"""
+
+from __future__ import print_function, unicode_literals
+import argparse
+import logging
+import os, os.path
+import random
+import re
+import string
+import subprocess
+import sys
+from collections import OrderedDict
+from ipaddress import IPv6Address, ip_network
+from pprint import pformat
+
+# Python 3
+def iteritems(d):
+    return iter(d.items())
+
+
+log = logging.getLogger(__name__)
+
+
+class VtyshException(Exception):
+    pass
+
+
+class Vtysh(object):
+    def __init__(self, bindir=None, confdir=None, sockdir=None, pathspace=None):
+        self.bindir = bindir
+        self.confdir = confdir
+        self.pathspace = pathspace
+        self.common_args = [os.path.join(bindir or "", "vtysh")]
+        if confdir:
+            self.common_args.extend(["--config_dir", confdir])
+        if sockdir:
+            self.common_args.extend(["--vty_socket", sockdir])
+        if pathspace:
+            self.common_args.extend(["-N", pathspace])
+
+    def _call(self, args, stdin=None, stdout=None, stderr=None):
+        kwargs = {}
+        if stdin is not None:
+            kwargs["stdin"] = stdin
+        if stdout is not None:
+            kwargs["stdout"] = stdout
+        if stderr is not None:
+            kwargs["stderr"] = stderr
+        return subprocess.Popen(self.common_args + args, **kwargs)
+
+    def _call_cmd(self, command, stdin=None, stdout=None, stderr=None):
+        if isinstance(command, list):
+            args = [item for sub in command for item in ["-c", sub]]
+        else:
+            args = ["-c", command]
+        return self._call(args, stdin, stdout, stderr)
+
+    def __call__(self, command, stdouts=None):
+        """
+        Call a CLI command (e.g. "show running-config")
+
+        Output text is automatically redirected, decoded and returned.
+        Multiple commands may be passed as list.
+        """
+        proc = self._call_cmd(command, stdout=subprocess.PIPE)
+        stdout, stderr = proc.communicate()
+        if proc.wait() != 0:
+            if stdouts is not None:
+                stdouts.append(stdout.decode("UTF-8"))
+            raise VtyshException(
+                'vtysh returned status %d for command "%s"' % (proc.returncode, command)
+            )
+        return stdout.decode("UTF-8")
+
+    def is_config_available(self):
+        """
+        Return False if no frr daemon is running or some other vtysh session is
+        in 'configuration terminal' mode which will prevent us from making any
+        configuration changes.
+        """
+
+        output = self("configure")
+
+        if "VTY configuration is locked by other VTY" in output:
+            log.error("vtysh 'configure' returned\n%s\n" % (output))
+            return False
+
+        return True
+
+    def exec_file(self, filename):
+        child = self._call(["-f", filename])
+        if child.wait() != 0:
+            raise VtyshException(
+                "vtysh (exec file) exited with status %d" % (child.returncode)
+            )
+
+    def mark_file(self, filename, stdin=None):
+        child = self._call(
+            ["-m", "-f", filename],
+            stdout=subprocess.PIPE,
+            stdin=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
+        try:
+            stdout, stderr = child.communicate()
+        except subprocess.TimeoutExpired:
+            child.kill()
+            stdout, stderr = child.communicate()
+            raise VtyshException("vtysh call timed out!")
+
+        if child.wait() != 0:
+            raise VtyshException(
+                "vtysh (mark file) exited with status %d:\n%s"
+                % (child.returncode, stderr)
+            )
+
+        return stdout.decode("UTF-8")
+
+    def mark_show_run(self, daemon=None):
+        cmd = "show running-config"
+        if daemon:
+            cmd += " %s" % daemon
+        cmd += " no-header"
+        show_run = self._call_cmd(cmd, stdout=subprocess.PIPE)
+        mark = self._call(
+            ["-m", "-f", "-"], stdin=show_run.stdout, stdout=subprocess.PIPE
+        )
+
+        show_run.wait()
+        stdout, stderr = mark.communicate()
+        mark.wait()
+
+        if show_run.returncode != 0:
+            raise VtyshException(
+                "vtysh (show running-config) exited with status %d:"
+                % (show_run.returncode)
+            )
+        if mark.returncode != 0:
+            raise VtyshException(
+                "vtysh (mark running-config) exited with status %d" % (mark.returncode)
+            )
+
+        return stdout.decode("UTF-8")
+
+
+class Context(object):
+    """
+        A Context object represents a section of frr configuration such as:
+    !
+    interface swp3
+     description swp3 -> r8's swp1
+     ipv6 nd suppress-ra
+     link-detect
+    !
+
+    or a single line context object such as this:
+
+    ip forwarding
+
+    """
+
+    def __init__(self, keys, lines):
+        self.keys = keys
+        self.lines = lines
+
+        # Keep a dictionary of the lines, this is to make it easy to tell if a
+        # line exists in this Context
+        self.dlines = OrderedDict()
+
+        for ligne in lines:
+            self.dlines[ligne] = True
+
+    def __str__(self):
+        return str(self.keys) + " : " + str(self.lines)
+
+    def add_lines(self, lines):
+        """
+        Add lines to specified context
+        """
+
+        self.lines.extend(lines)
+
+        for ligne in lines:
+            self.dlines[ligne] = True
+
+
+def get_normalized_es_id(line):
+    """
+    The es-id or es-sys-mac need to be converted to lower case
+    """
+    sub_strs = ["evpn mh es-id", "evpn mh es-sys-mac"]
+    for sub_str in sub_strs:
+        obj = re.match(sub_str + " (?P<esi>\S*)", line)
+        if obj:
+            line = "%s %s" % (sub_str, obj.group("esi").lower())
+            break
+    return line
+
+
+def get_normalized_mac_ip_line(line):
+    if line.startswith("evpn mh es"):
+        return get_normalized_es_id(line)
+
+    if not "ipv6 add" in line:
+        return get_normalized_ipv6_line(line)
+
+    return line
+
+
+class Config(object):
+    """
+    A frr configuration is stored in a Config object. A Config object
+    contains a dictionary of Context objects where the Context keys
+    ('router ospf' for example) are our dictionary key.
+    """
+
+    def __init__(self, vtysh):
+        self.lines = []
+        self.contexts = OrderedDict()
+        self.vtysh = vtysh
+
+    def load_from_file(self, filename):
+        """
+        Read configuration from specified file and slurp it into internal memory
+        The internal representation has been marked appropriately by passing it
+        through vtysh with the -m parameter
+        """
+        log.info("Loading Config object from file %s", filename)
+
+        file_output = self.vtysh.mark_file(filename)
+
+        for line in file_output.split("\n"):
+            line = line.strip()
+
+            # Compress duplicate whitespaces
+            line = " ".join(line.split())
+
+            if ":" in line:
+                line = get_normalized_mac_ip_line(line)
+
+            # vrf static routes can be added in two ways. The old way is:
+            #
+            # "ip route x.x.x.x/x y.y.y.y vrf <vrfname>"
+            #
+            # but it's rendered in the configuration as the new way::
+            #
+            # vrf <vrf-name>
+            #  ip route x.x.x.x/x y.y.y.y
+            #  exit-vrf
+            #
+            # this difference causes frr-reload to not consider them a
+            # match and delete vrf static routes incorrectly.
+            # fix the old way to match new "show running" output so a
+            # proper match is found.
+            if (
+                line.startswith("ip route ") or line.startswith("ipv6 route ")
+            ) and " vrf " in line:
+                newline = line.split(" ")
+                vrf_index = newline.index("vrf")
+                vrf_ctx = newline[vrf_index] + " " + newline[vrf_index + 1]
+                del newline[vrf_index : vrf_index + 2]
+                newline = " ".join(newline)
+                self.lines.append(vrf_ctx)
+                self.lines.append(newline)
+                self.lines.append("exit-vrf")
+                line = "end"
+
+            self.lines.append(line)
+
+        self.load_contexts()
+
+    def load_from_show_running(self, daemon):
+        """
+        Read running configuration and slurp it into internal memory
+        The internal representation has been marked appropriately by passing it
+        through vtysh with the -m parameter
+        """
+        log.info("Loading Config object from vtysh show running")
+
+        config_text = self.vtysh.mark_show_run(daemon)
+
+        for line in config_text.split("\n"):
+            line = line.strip()
+
+            if (
+                line == "Building configuration..."
+                or line == "Current configuration:"
+                or not line
+            ):
+                continue
+
+            self.lines.append(line)
+
+        self.load_contexts()
+
+    def get_lines(self):
+        """
+        Return the lines read in from the configuration
+        """
+        return "\n".join(self.lines)
+
+    def get_contexts(self):
+        """
+        Return the parsed context as strings for display, log etc.
+        """
+        for (_, ctx) in sorted(iteritems(self.contexts)):
+            print(str(ctx))
+
+    def save_contexts(self, key, lines):
+        """
+        Save the provided key and lines as a context
+        """
+        if not key:
+            return
+
+        # IP addresses specified in "network" statements, "ip prefix-lists"
+        # etc. can differ in the host part of the specification the user
+        # provides and what the running config displays. For example, user can
+        # specify 11.1.1.1/24, and the running config displays this as
+        # 11.1.1.0/24. Ensure we don't do a needless operation for such lines.
+        # IS-IS & OSPFv3 have no "network" support.
+        re_key_rt = re.match(r"(ip|ipv6)\s+route\s+([A-Fa-f:.0-9/]+)(.*)$", key[0])
+        if re_key_rt:
+            addr = re_key_rt.group(2)
+            if "/" in addr:
+                try:
+                    newaddr = ip_network(addr, strict=False)
+                    key[0] = "%s route %s/%s%s" % (
+                        re_key_rt.group(1),
+                        str(newaddr.network_address),
+                        newaddr.prefixlen,
+                        re_key_rt.group(3),
+                    )
+                except ValueError:
+                    pass
+
+        re_key_rt = re.match(
+            r"(ip|ipv6)\s+prefix-list(.*)(permit|deny)\s+([A-Fa-f:.0-9/]+)(.*)$", key[0]
+        )
+        if re_key_rt:
+            addr = re_key_rt.group(4)
+            if "/" in addr:
+                try:
+                    network_addr = ip_network(addr, strict=False)
+                    newaddr = "%s/%s" % (
+                        str(network_addr.network_address),
+                        network_addr.prefixlen,
+                    )
+                except ValueError:
+                    newaddr = addr
+            else:
+                newaddr = addr
+
+            legestr = re_key_rt.group(5)
+            re_lege = re.search(r"(.*)le\s+(\d+)\s+ge\s+(\d+)(.*)", legestr)
+            if re_lege:
+                legestr = "%sge %s le %s%s" % (
+                    re_lege.group(1),
+                    re_lege.group(3),
+                    re_lege.group(2),
+                    re_lege.group(4),
+                )
+
+            key[0] = "%s prefix-list%s%s %s%s" % (
+                re_key_rt.group(1),
+                re_key_rt.group(2),
+                re_key_rt.group(3),
+                newaddr,
+                legestr,
+            )
+
+        if lines and key[0].startswith("router bgp"):
+            newlines = []
+            for line in lines:
+                re_net = re.match(r"network\s+([A-Fa-f:.0-9/]+)(.*)$", line)
+                if re_net:
+                    addr = re_net.group(1)
+                    if "/" not in addr and key[0].startswith("router bgp"):
+                        # This is most likely an error because with no
+                        # prefixlen, BGP treats the prefixlen as 8
+                        addr = addr + "/8"
+
+                    try:
+                        network_addr = ip_network(addr, strict=False)
+                        line = "network %s/%s %s" % (
+                            str(network_addr.network_address),
+                            network_addr.prefixlen,
+                            re_net.group(2),
+                        )
+                        newlines.append(line)
+                    except ValueError:
+                        # Really this should be an error. Whats a network
+                        # without an IP Address following it ?
+                        newlines.append(line)
+                else:
+                    newlines.append(line)
+            lines = newlines
+
+        # More fixups in user specification and what running config shows.
+        # "null0" in routes must be replaced by Null0.
+        if (
+            key[0].startswith("ip route")
+            or key[0].startswith("ipv6 route")
+            and "null0" in key[0]
+        ):
+            key[0] = re.sub(r"\s+null0(\s*$)", " Null0", key[0])
+
+        if lines and key[0].startswith("vrf "):
+            newlines = []
+            for line in lines:
+                if line.startswith("ip route ") or line.startswith("ipv6 route "):
+                    if "null0" in line:
+                        line = re.sub(r"\s+null0(\s*$)", " Null0", line)
+                    newlines.append(line)
+                else:
+                    newlines.append(line)
+            lines = newlines
+
+        if lines:
+            if tuple(key) not in self.contexts:
+                ctx = Context(tuple(key), lines)
+                self.contexts[tuple(key)] = ctx
+            else:
+                ctx = self.contexts[tuple(key)]
+                ctx.add_lines(lines)
+
+        else:
+            if tuple(key) not in self.contexts:
+                ctx = Context(tuple(key), [])
+                self.contexts[tuple(key)] = ctx
+
+    def load_contexts(self):
+        """
+        Parse the configuration and create contexts for each appropriate block
+
+        The end of a context is flagged via the 'end' keyword:
+
+        !
+        interface swp52
+         ipv6 nd suppress-ra
+         link-detect
+        !
+        end
+        router bgp 10
+         bgp router-id 10.0.0.1
+         bgp log-neighbor-changes
+         no bgp default ipv4-unicast
+         neighbor EBGP peer-group
+         neighbor EBGP advertisement-interval 1
+         neighbor EBGP timers connect 10
+         neighbor 2001:40:1:4::6 remote-as 40
+         neighbor 2001:40:1:8::a remote-as 40
+        !
+        end
+         address-family ipv6
+         neighbor IBGPv6 activate
+         neighbor 2001:10::2 peer-group IBGPv6
+         neighbor 2001:10::3 peer-group IBGPv6
+         exit-address-family
+        !
+        end
+        router ospf
+         ospf router-id 10.0.0.1
+         log-adjacency-changes detail
+         timers throttle spf 0 50 5000
+        !
+        end
+
+        The code assumes that its working on the output from the "vtysh -m"
+        command. That provides the appropriate markers to signify end of
+        a context. This routine uses that to build the contexts for the
+        config.
+
+        There are single line contexts such as "log file /media/node/zebra.log"
+        and multi-line contexts such as "router ospf" and subcontexts
+        within a context such as "address-family" within "router bgp"
+        In each of these cases, the first line of the context becomes the
+        key of the context. So "router bgp 10" is the key for the non-address
+        family part of bgp, "router bgp 10, address-family ipv6 unicast" is
+        the key for the subcontext and so on.
+
+        This dictionary contains a tree of all commands that we know start a
+        new multi-line context. All other commands are treated either as
+        commands inside a multi-line context or as single-line contexts. This
+        dictionary should be updated whenever a new node is added to FRR.
+        """
+        ctx_keywords = {
+            "router bgp ": {
+                "address-family ": {
+                    "vni ": {},
+                },
+                "vnc defaults": {},
+                "vnc nve-group ": {},
+                "vnc l2-group ": {},
+                "vrf-policy ": {},
+                "bmp targets ": {},
+                "segment-routing srv6": {},
+            },
+            "router rip": {},
+            "router ripng": {},
+            "router isis ": {},
+            "router openfabric ": {},
+            "router ospf": {},
+            "router ospf6": {},
+            "router eigrp ": {},
+            "router babel": {},
+            "mpls ldp": {"address-family ": {"interface ": {}}},
+            "l2vpn ": {"member pseudowire ": {}},
+            "key chain ": {"key ": {}},
+            "vrf ": {},
+            "interface ": {"link-params": {}},
+            "pseudowire ": {},
+            "segment-routing": {
+                "traffic-eng": {
+                    "segment-list ": {},
+                    "policy ": {"candidate-path ": {}},
+                    "pcep": {"pcc": {}, "pce ": {}, "pce-config ": {}},
+                },
+                "srv6": {"locators": {"locator ": {}}},
+            },
+            "nexthop-group ": {},
+            "route-map ": {},
+            "pbr-map ": {},
+            "rpki": {},
+            "bfd": {"peer ": {}, "profile ": {}},
+            "line vty": {},
+        }
+
+        # stack of context keys
+        ctx_keys = []
+        # stack of context keywords
+        cur_ctx_keywords = [ctx_keywords]
+        # list of stored commands
+        cur_ctx_lines = []
+
+        for line in self.lines:
+
+            if not line:
+                continue
+
+            if line.startswith("!") or line.startswith("#"):
+                continue
+
+            if line.startswith("exit"):
+                # ignore on top level
+                if len(ctx_keys) == 0:
+                    continue
+
+                # save current context
+                self.save_contexts(ctx_keys, cur_ctx_lines)
+
+                # exit current context
+                log.debug("LINE %-50s: exit context %-50s", line, ctx_keys)
+
+                ctx_keys.pop()
+                cur_ctx_keywords.pop()
+                cur_ctx_lines = []
+
+                continue
+
+            if line.startswith("end"):
+                # exit all contexts
+                while len(ctx_keys) > 0:
+                    # save current context
+                    self.save_contexts(ctx_keys, cur_ctx_lines)
+
+                    # exit current context
+                    log.debug("LINE %-50s: exit context %-50s", line, ctx_keys)
+
+                    ctx_keys.pop()
+                    cur_ctx_keywords.pop()
+                    cur_ctx_lines = []
+
+                continue
+
+            new_ctx = False
+
+            # check if the line is a context-entering keyword
+            for k, v in cur_ctx_keywords[-1].items():
+                if line.startswith(k):
+                    # candidate-path is a special case. It may be a node and
+                    # may be a single-line command. The distinguisher is the
+                    # word "dynamic" or "explicit" at the middle of the line.
+                    # It was perhaps not the best choice by the pathd authors
+                    # but we have what we have.
+                    if k == "candidate-path " and "explicit" in line:
+                        # this is a single-line command
+                        break
+
+                    # save current context
+                    self.save_contexts(ctx_keys, cur_ctx_lines)
+
+                    # enter new context
+                    new_ctx = True
+                    ctx_keys.append(line)
+                    cur_ctx_keywords.append(v)
+                    cur_ctx_lines = []
+
+                    log.debug("LINE %-50s: enter context %-50s", line, ctx_keys)
+                    break
+
+            if new_ctx:
+                continue
+
+            if len(ctx_keys) == 0:
+                log.debug("LINE %-50s: single-line context", line)
+                self.save_contexts([line], [])
+            else:
+                log.debug("LINE %-50s: add to current context %-50s", line, ctx_keys)
+                cur_ctx_lines.append(line)
+
+        # Save the context of the last one
+        if len(ctx_keys) > 0:
+            self.save_contexts(ctx_keys, cur_ctx_lines)
+
+
+def lines_to_config(ctx_keys, line, delete):
+    """
+    Return the command as it would appear in frr.conf
+    """
+    cmd = []
+
+    if line:
+        for (i, ctx_key) in enumerate(ctx_keys):
+            cmd.append(" " * i + ctx_key)
+
+        line = line.lstrip()
+        indent = len(ctx_keys) * " "
+
+        # There are some commands that are on by default so their "no" form will be
+        # displayed in the config.  "no bgp default ipv4-unicast" is one of these.
+        # If we need to remove this line we do so by adding "bgp default ipv4-unicast",
+        # not by doing a "no no bgp default ipv4-unicast"
+        if delete:
+            if line.startswith("no "):
+                cmd.append("%s%s" % (indent, line[3:]))
+            else:
+                cmd.append("%sno %s" % (indent, line))
+
+        else:
+            cmd.append(indent + line)
+
+    # If line is None then we are typically deleting an entire
+    # context ('no router ospf' for example)
+    else:
+        for i, ctx_key in enumerate(ctx_keys[:-1]):
+            cmd.append("%s%s" % (" " * i, ctx_key))
+
+        # Only put the 'no' on the last sub-context
+        if delete:
+            if ctx_keys[-1].startswith("no "):
+                cmd.append("%s%s" % (" " * (len(ctx_keys) - 1), ctx_keys[-1][3:]))
+            else:
+                cmd.append("%sno %s" % (" " * (len(ctx_keys) - 1), ctx_keys[-1]))
+        else:
+            cmd.append("%s%s" % (" " * (len(ctx_keys) - 1), ctx_keys[-1]))
+
+    return cmd
+
+
+def get_normalized_ipv6_line(line):
+    """
+    Return a normalized IPv6 line as produced by frr,
+    with all letters in lower case and trailing and leading
+    zeros removed, and only the network portion present if
+    the IPv6 word is a network
+    """
+    norm_line = ""
+    words = line.split(" ")
+    for word in words:
+        if ":" in word:
+            norm_word = None
+            if "/" in word:
+                try:
+                    v6word = ip_network(word, strict=False)
+                    norm_word = "%s/%s" % (
+                        str(v6word.network_address),
+                        v6word.prefixlen,
+                    )
+                except ValueError:
+                    pass
+            if not norm_word:
+                try:
+                    norm_word = "%s" % IPv6Address(word)
+                except ValueError:
+                    norm_word = word
+        else:
+            norm_word = word
+        norm_line = norm_line + " " + norm_word
+
+    return norm_line.strip()
+
+
+def line_exist(lines, target_ctx_keys, target_line, exact_match=True):
+    for (ctx_keys, line) in lines:
+        if ctx_keys == target_ctx_keys:
+            if exact_match:
+                if line == target_line:
+                    return True
+            else:
+                if line.startswith(target_line):
+                    return True
+    return False
+
+
+def check_for_exit_vrf(lines_to_add, lines_to_del):
+
+    # exit-vrf is a bit tricky.  If the new config is missing it but we
+    # have configs under a vrf, we need to add it at the end to do the
+    # right context changes.  If exit-vrf exists in both the running and
+    # new config, we cannot delete it or it will break context changes.
+    add_exit_vrf = False
+    index = 0
+
+    for (ctx_keys, line) in lines_to_add:
+        if add_exit_vrf == True:
+            if ctx_keys[0] != prior_ctx_key:
+                insert_key = ((prior_ctx_key),)
+                lines_to_add.insert(index, ((insert_key, "exit-vrf")))
+                add_exit_vrf = False
+
+        if ctx_keys[0].startswith("vrf") and line:
+            if line != "exit-vrf":
+                add_exit_vrf = True
+                prior_ctx_key = ctx_keys[0]
+            else:
+                add_exit_vrf = False
+        index += 1
+
+    for (ctx_keys, line) in lines_to_del:
+        if line == "exit-vrf":
+            if line_exist(lines_to_add, ctx_keys, line):
+                lines_to_del.remove((ctx_keys, line))
+
+    return (lines_to_add, lines_to_del)
+
+
+def bgp_delete_inst_move_line(lines_to_del):
+    # Deletion of bgp default inst followed by
+    # bgp vrf inst leads to issue of default
+    # instance can not be removed.
+    # Move the bgp default instance line to end.
+    bgp_defult_inst = False
+    bgp_vrf_inst = False
+
+    for (ctx_keys, line) in lines_to_del:
+        # Find bgp default inst
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and not line
+            and "vrf" not in ctx_keys[0]
+        ):
+            bgp_defult_inst = True
+        # Find bgp vrf inst
+        if ctx_keys[0].startswith("router bgp") and not line and "vrf" in ctx_keys[0]:
+            bgp_vrf_inst = True
+
+    if bgp_defult_inst and bgp_vrf_inst:
+        for (ctx_keys, line) in lines_to_del:
+            # move bgp default inst to end
+            if (
+                ctx_keys[0].startswith("router bgp")
+                and not line
+                and "vrf" not in ctx_keys[0]
+            ):
+                lines_to_del.remove((ctx_keys, line))
+                lines_to_del.append((ctx_keys, line))
+
+
+def bgp_delete_nbr_remote_as_line(lines_to_add):
+    # Handle deletion of neighbor <nbr> remote-as line from
+    # lines_to_add if the nbr is configured with peer-group and
+    # peer-group has remote-as config present.
+    # 'neighbor <nbr> remote-as change on peer is not allowed
+    # if the peer is part of peer-group and peer-group has
+    # remote-as config.
+
+    pg_dict = dict()
+    found_pg_cmd = False
+
+    # Find all peer-group commands; create dict of each peer-group
+    # to store assoicated neighbor as value
+    for ctx_keys, line in lines_to_add:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            # {'router bgp 65001': {'PG': [], 'PG1': []},
+            # 'router bgp 65001 vrf vrf1': {'PG': [], 'PG1': []}}
+            if ctx_keys[0] not in pg_dict:
+                pg_dict[ctx_keys[0]] = dict()
+            # find 'neighbor <pg_name> peer-group'
+            re_pg = re.match("neighbor (\S+) peer-group$", line)
+            if re_pg and re_pg.group(1) not in pg_dict[ctx_keys[0]]:
+                pg_dict[ctx_keys[0]][re_pg.group(1)] = {
+                    "nbr": list(),
+                    "remoteas": False,
+                }
+                found_pg_cmd = True
+
+    # Do nothing if there is no any "peer-group"
+    if found_pg_cmd is False:
+        return
+
+    # Find peer-group with remote-as command, also search neighbor
+    # associated to peer-group and store into peer-group dict
+    for ctx_keys, line in lines_to_add:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            if ctx_keys[0] in pg_dict:
+                for pg_key in pg_dict[ctx_keys[0]]:
+                    # Find 'neighbor <pg_name> remote-as'
+                    pg_rmtas = "neighbor %s remote-as (\S+)" % pg_key
+                    re_pg_rmtas = re.search(pg_rmtas, line)
+                    if re_pg_rmtas:
+                        pg_dict[ctx_keys[0]][pg_key]["remoteas"] = True
+
+                    # Find 'neighbor <peer> [interface] peer-group <pg_name>'
+                    nb_pg = "neighbor (\S+) peer-group %s$" % pg_key
+                    re_nbr_pg = re.search(nb_pg, line)
+                    if (
+                        re_nbr_pg
+                        and re_nbr_pg.group(1) not in pg_dict[ctx_keys[0]][pg_key]
+                    ):
+                        pg_dict[ctx_keys[0]][pg_key]["nbr"].append(re_nbr_pg.group(1))
+
+    # Find any neighbor <nbr> remote-as config line check if the nbr
+    # is in the peer group's list of nbrs. Remove 'neighbor <nbr> remote-as <>'
+    # from lines_to_add.
+    lines_to_del_from_add = []
+    for ctx_keys, line in lines_to_add:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            nbr_rmtas = "neighbor (\S+) remote-as.*"
+            re_nbr_rmtas = re.search(nbr_rmtas, line)
+            if re_nbr_rmtas and ctx_keys[0] in pg_dict:
+                for pg in pg_dict[ctx_keys[0]]:
+                    if pg_dict[ctx_keys[0]][pg]["remoteas"] == True:
+                        for nbr in pg_dict[ctx_keys[0]][pg]["nbr"]:
+                            if re_nbr_rmtas.group(1) == nbr:
+                                lines_to_del_from_add.append((ctx_keys, line))
+
+    for ctx_keys, line in lines_to_del_from_add:
+        lines_to_add.remove((ctx_keys, line))
+
+
+def bgp_remove_neighbor_cfg(lines_to_del, del_nbr_dict):
+
+    # This method handles deletion of bgp neighbor configs,
+    # if there is neighbor to peer-group cmd is in delete list.
+    # As 'no neighbor .* peer-group' deletes the neighbor,
+    # subsequent neighbor speciic config line deletion results
+    # in error.
+    lines_to_del_to_del = []
+
+    for (ctx_keys, line) in lines_to_del:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            if ctx_keys[0] in del_nbr_dict:
+                for nbr in del_nbr_dict[ctx_keys[0]]:
+                    re_nbr_pg = re.search("neighbor (\S+) .*peer-group (\S+)", line)
+                    nb_exp = "neighbor %s .*" % nbr
+                    if not re_nbr_pg:
+                        re_nb = re.search(nb_exp, line)
+                        if re_nb:
+                            lines_to_del_to_del.append((ctx_keys, line))
+
+    for (ctx_keys, line) in lines_to_del_to_del:
+        lines_to_del.remove((ctx_keys, line))
+
+
+def delete_move_lines(lines_to_add, lines_to_del):
+    # This method handles deletion of bgp peer group config.
+    # The objective is to delete config lines related to peers
+    # associated with the peer-group and move the peer-group
+    # config line to the end of the lines_to_del list.
+
+    bgp_delete_nbr_remote_as_line(lines_to_add)
+
+    del_dict = dict()
+    del_nbr_dict = dict()
+    # Stores the lines to move to the end of the pending list.
+    lines_to_del_to_del = []
+    # Stores the lines to move to end of the pending list.
+    lines_to_del_to_app = []
+    found_pg_del_cmd = False
+
+    # When "neighbor <pg_name> peer-group" under a bgp instance is removed,
+    # it also deletes the associated peer config. Any config line below no form of
+    # peer-group related to a peer are errored out as the peer no longer exists.
+    # To cleanup peer-group and associated peer(s) configs:
+    # - Remove all the peers config lines from the pending list (lines_to_del list).
+    # - Move peer-group deletion line to the end of the pending list, to allow
+    # removal of any of the peer-group specific configs.
+    #
+    # Create a dictionary of config context (i.e. router bgp vrf x).
+    # Under each context node, create a dictionary of a peer-group name.
+    # Append a peer associated to the peer-group into a list under a peer-group node.
+    # Remove all of the peer associated config lines from the pending list.
+    # Append peer-group deletion line to end of the pending list.
+    #
+    # Example:
+    #   neighbor underlay peer-group
+    #   neighbor underlay remote-as external
+    #   neighbor underlay advertisement-interval 0
+    #   neighbor underlay timers 3 9
+    #   neighbor underlay timers connect 10
+    #   neighbor swp1 interface peer-group underlay
+    #   neighbor swp1 advertisement-interval 0
+    #   neighbor swp1 timers 3 9
+    #   neighbor swp1 timers connect 10
+    #   neighbor swp2 interface peer-group underlay
+    #   neighbor swp2 advertisement-interval 0
+    #   neighbor swp2 timers 3 9
+    #   neighbor swp2 timers connect 10
+    #   neighbor swp3 interface peer-group underlay
+    #   neighbor uplink1 interface remote-as internal
+    #   neighbor uplink1 advertisement-interval 0
+    #   neighbor uplink1 timers 3 9
+    #   neighbor uplink1 timers connect 10
+
+    # New order:
+    #   "router bgp 200  no bgp bestpath as-path multipath-relax"
+    #   "router bgp 200  no neighbor underlay advertisement-interval 0"
+    #   "router bgp 200  no neighbor underlay timers 3 9"
+    #   "router bgp 200  no neighbor underlay timers connect 10"
+    #   "router bgp 200  no neighbor uplink1 advertisement-interval 0"
+    #   "router bgp 200  no neighbor uplink1 timers 3 9"
+    #   "router bgp 200  no neighbor uplink1 timers connect 10"
+    #   "router bgp 200  no neighbor underlay remote-as external"
+    #   "router bgp 200  no neighbor uplink1 interface remote-as internal"
+    #   "router bgp 200  no neighbor underlay peer-group"
+
+    for (ctx_keys, line) in lines_to_del:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            # When 'neighbor <peer> remote-as <>' is removed it deletes the peer,
+            # there might be a peer associated config which also needs to be removed
+            # prior to peer.
+            # Append the 'neighbor <peer> remote-as <>' to the lines_to_del.
+            # Example:
+            #
+            #  neighbor uplink1 interface remote-as internal
+            #  neighbor uplink1 advertisement-interval 0
+            #  neighbor uplink1 timers 3 9
+            #  neighbor uplink1 timers connect 10
+
+            #  Move to end:
+            #  neighbor uplink1 advertisement-interval 0
+            #  neighbor uplink1 timers 3 9
+            #  neighbor uplink1 timers connect 10
+            #  ...
+            #
+            #  neighbor uplink1 interface remote-as internal
+            #
+            # 'no neighbor peer [interface] remote-as <>'
+            nb_remoteas = "neighbor (\S+) .*remote-as (\S+)"
+            re_nb_remoteas = re.search(nb_remoteas, line)
+            if re_nb_remoteas:
+                lines_to_del_to_app.append((ctx_keys, line))
+
+            # 'no neighbor peer [interface] peer-group <>' is in lines_to_del
+            # copy the neighbor and look for all config removal lines associated
+            # to neighbor and delete them from the lines_to_del
+            re_nbr_pg = re.search("neighbor (\S+) .*peer-group (\S+)", line)
+            if re_nbr_pg:
+                if ctx_keys[0] not in del_nbr_dict:
+                    del_nbr_dict[ctx_keys[0]] = list()
+                if re_nbr_pg.group(1) not in del_nbr_dict[ctx_keys[0]]:
+                    del_nbr_dict[ctx_keys[0]].append(re_nbr_pg.group(1))
+
+            # {'router bgp 65001': {'PG': [], 'PG1': []},
+            # 'router bgp 65001 vrf vrf1': {'PG': [], 'PG1': []}}
+            if ctx_keys[0] not in del_dict:
+                del_dict[ctx_keys[0]] = dict()
+            # find 'no neighbor <pg_name> peer-group'
+            re_pg = re.match("neighbor (\S+) peer-group$", line)
+            if re_pg and re_pg.group(1) not in del_dict[ctx_keys[0]]:
+                del_dict[ctx_keys[0]][re_pg.group(1)] = list()
+                found_pg_del_cmd = True
+
+    if found_pg_del_cmd == False:
+        bgp_delete_inst_move_line(lines_to_del)
+        if del_nbr_dict:
+            bgp_remove_neighbor_cfg(lines_to_del, del_nbr_dict)
+        return (lines_to_add, lines_to_del)
+
+    for (ctx_keys, line) in lines_to_del_to_app:
+        lines_to_del.remove((ctx_keys, line))
+        lines_to_del.append((ctx_keys, line))
+
+    # {'router bgp 65001': {'PG': ['10.1.1.2'], 'PG1': ['10.1.1.21']},
+    #  'router bgp 65001 vrf vrf1': {'PG': ['10.1.1.2'], 'PG1': ['10.1.1.21']}}
+    for (ctx_keys, line) in lines_to_del:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            if ctx_keys[0] in del_dict:
+                for pg_key in del_dict[ctx_keys[0]]:
+                    # 'neighbor <peer> [interface] peer-group <pg_name>'
+                    nb_pg = "neighbor (\S+) .*peer-group %s$" % pg_key
+                    re_nbr_pg = re.search(nb_pg, line)
+                    if (
+                        re_nbr_pg
+                        and re_nbr_pg.group(1) not in del_dict[ctx_keys[0]][pg_key]
+                    ):
+                        del_dict[ctx_keys[0]][pg_key].append(re_nbr_pg.group(1))
+
+    lines_to_del_to_app = []
+    for (ctx_keys, line) in lines_to_del:
+        if (
+            ctx_keys[0].startswith("router bgp")
+            and line
+            and line.startswith("neighbor ")
+        ):
+            if ctx_keys[0] in del_dict:
+                for pg in del_dict[ctx_keys[0]]:
+                    for nbr in del_dict[ctx_keys[0]][pg]:
+                        nb_exp = "neighbor %s .*" % nbr
+                        re_nb = re.search(nb_exp, line)
+                        # add peer configs to delete list.
+                        if re_nb and line not in lines_to_del_to_del:
+                            lines_to_del_to_del.append((ctx_keys, line))
+
+                    pg_exp = "neighbor %s peer-group$" % pg
+                    re_pg = re.match(pg_exp, line)
+                    if re_pg:
+                        lines_to_del_to_app.append((ctx_keys, line))
+
+    for (ctx_keys, line) in lines_to_del_to_del:
+        lines_to_del.remove((ctx_keys, line))
+
+    for (ctx_keys, line) in lines_to_del_to_app:
+        lines_to_del.remove((ctx_keys, line))
+        lines_to_del.append((ctx_keys, line))
+
+    bgp_delete_inst_move_line(lines_to_del)
+
+    return (lines_to_add, lines_to_del)
+
+
+def ignore_delete_re_add_lines(lines_to_add, lines_to_del):
+
+    # Quite possibly the most confusing (while accurate) variable names in history
+    lines_to_add_to_del = []
+    lines_to_del_to_del = []
+
+    for (ctx_keys, line) in lines_to_del:
+        deleted = False
+
+        # If there is a change in the segment routing block ranges, do it
+        # in-place, to avoid requesting spurious label chunks which might fail
+        if line and "segment-routing global-block" in line:
+            for (add_key, add_line) in lines_to_add:
+                if (
+                    ctx_keys[0] == add_key[0]
+                    and add_line
+                    and "segment-routing global-block" in add_line
+                ):
+                    lines_to_del_to_del.append((ctx_keys, line))
+                    break
+            continue
+
+        if ctx_keys[0].startswith("router bgp") and line:
+
+            if line.startswith("neighbor "):
+                # BGP changed how it displays swpX peers that are part of peer-group. Older
+                # versions of frr would display these on separate lines:
+                #     neighbor swp1 interface
+                #     neighbor swp1 peer-group FOO
+                #
+                # but today we display via a single line
+                #     neighbor swp1 interface peer-group FOO
+                #
+                # This change confuses frr-reload.py so check to see if we are deleting
+                #     neighbor swp1 interface peer-group FOO
+                #
+                # and adding
+                #     neighbor swp1 interface
+                #     neighbor swp1 peer-group FOO
+                #
+                # If so then chop the del line and the corresponding add lines
+                re_swpx_int_peergroup = re.search(
+                    "neighbor (\S+) interface peer-group (\S+)", line
+                )
+                re_swpx_int_v6only_peergroup = re.search(
+                    "neighbor (\S+) interface v6only peer-group (\S+)", line
+                )
+
+                if re_swpx_int_peergroup or re_swpx_int_v6only_peergroup:
+                    swpx_interface = None
+                    swpx_peergroup = None
+
+                    if re_swpx_int_peergroup:
+                        swpx = re_swpx_int_peergroup.group(1)
+                        peergroup = re_swpx_int_peergroup.group(2)
+                        swpx_interface = "neighbor %s interface" % swpx
+                    elif re_swpx_int_v6only_peergroup:
+                        swpx = re_swpx_int_v6only_peergroup.group(1)
+                        peergroup = re_swpx_int_v6only_peergroup.group(2)
+                        swpx_interface = "neighbor %s interface v6only" % swpx
+
+                    swpx_peergroup = "neighbor %s peer-group %s" % (swpx, peergroup)
+                    found_add_swpx_interface = line_exist(
+                        lines_to_add, ctx_keys, swpx_interface
+                    )
+                    found_add_swpx_peergroup = line_exist(
+                        lines_to_add, ctx_keys, swpx_peergroup
+                    )
+                    tmp_ctx_keys = tuple(list(ctx_keys))
+
+                    if not found_add_swpx_peergroup:
+                        tmp_ctx_keys = list(ctx_keys)
+                        tmp_ctx_keys.append("address-family ipv4 unicast")
+                        tmp_ctx_keys = tuple(tmp_ctx_keys)
+                        found_add_swpx_peergroup = line_exist(
+                            lines_to_add, tmp_ctx_keys, swpx_peergroup
+                        )
+
+                        if not found_add_swpx_peergroup:
+                            tmp_ctx_keys = list(ctx_keys)
+                            tmp_ctx_keys.append("address-family ipv6 unicast")
+                            tmp_ctx_keys = tuple(tmp_ctx_keys)
+                            found_add_swpx_peergroup = line_exist(
+                                lines_to_add, tmp_ctx_keys, swpx_peergroup
+                            )
+
+                    if found_add_swpx_interface and found_add_swpx_peergroup:
+                        deleted = True
+                        lines_to_del_to_del.append((ctx_keys, line))
+                        lines_to_add_to_del.append((ctx_keys, swpx_interface))
+                        lines_to_add_to_del.append((tmp_ctx_keys, swpx_peergroup))
+
+                # Changing the bfd timers on neighbors is allowed without doing
+                # a delete/add process. Since doing a "no neighbor blah bfd
+                # ..." will cause the peer to bounce unnecessarily, just skip
+                # the delete and just do the add.
+                re_nbr_bfd_timers = re.search(
+                    r"neighbor (\S+) bfd (\S+) (\S+) (\S+)", line
+                )
+
+                if re_nbr_bfd_timers:
+                    nbr = re_nbr_bfd_timers.group(1)
+                    bfd_nbr = "neighbor %s" % nbr
+                    bfd_search_string = bfd_nbr + r" bfd (\S+) (\S+) (\S+)"
+
+                    for (ctx_keys, add_line) in lines_to_add:
+                        if ctx_keys[0].startswith("router bgp"):
+                            re_add_nbr_bfd_timers = re.search(
+                                bfd_search_string, add_line
+                            )
+
+                            if re_add_nbr_bfd_timers:
+                                found_add_bfd_nbr = line_exist(
+                                    lines_to_add, ctx_keys, bfd_nbr, False
+                                )
+
+                                if found_add_bfd_nbr:
+                                    lines_to_del_to_del.append((ctx_keys, line))
+
+                # Neighbor changes of route-maps need to be accounted for in
+                # that we do not want to do a `no route-map...` `route-map
+                # ....` when changing a route-map.  This is bad mojo as that we
+                # will send/receive data we don't want.  Additionally we need
+                # to ensure that if we have different afi/safi variants that
+                # they actually match and if we are going from a very old style
+                # command such that the neighbor command is under the `router
+                # bgp ..` node that we need to handle that appropriately
+                re_nbr_rm = re.search("neighbor(.*)route-map(.*)(in|out)$", line)
+                if re_nbr_rm:
+                    adjust_for_bgp_node = 0
+                    neighbor_name = re_nbr_rm.group(1)
+                    rm_name_del = re_nbr_rm.group(2)
+                    dir = re_nbr_rm.group(3)
+                    search = "neighbor%sroute-map(.*)%s" % (neighbor_name, dir)
+                    save_line = "EMPTY"
+                    for (ctx_keys_al, add_line) in lines_to_add:
+                        if ctx_keys_al[0].startswith("router bgp"):
+                            if add_line:
+                                rm_match = re.search(search, add_line)
+                            if rm_match:
+                                rm_name_add = rm_match.group(1)
+                                if rm_name_add == rm_name_del:
+                                    continue
+                                if len(ctx_keys_al) == 1:
+                                    save_line = line
+                                    adjust_for_bgp_node = 1
+                                else:
+                                    if (
+                                        len(ctx_keys) > 1
+                                        and len(ctx_keys_al) > 1
+                                        and ctx_keys[1] == ctx_keys_al[1]
+                                    ):
+                                        lines_to_del_to_del.append((ctx_keys_al, line))
+
+                    if adjust_for_bgp_node == 1:
+                        for (ctx_keys_dl, dl_line) in lines_to_del:
+                            if (
+                                ctx_keys_dl[0].startswith("router bgp")
+                                and len(ctx_keys_dl) > 1
+                                and ctx_keys_dl[1] == "address-family ipv4 unicast"
+                            ):
+                                if save_line == dl_line:
+                                    lines_to_del_to_del.append((ctx_keys_dl, save_line))
+
+                # We changed how we display the neighbor interface command. Older
+                # versions of frr would display the following:
+                #     neighbor swp1 interface
+                #     neighbor swp1 remote-as external
+                #     neighbor swp1 capability extended-nexthop
+                #
+                # but today we display via a single line
+                #     neighbor swp1 interface remote-as external
+                #
+                # and capability extended-nexthop is no longer needed because we
+                # automatically enable it when the neighbor is of type interface.
+                #
+                # This change confuses frr-reload.py so check to see if we are deleting
+                #     neighbor swp1 interface remote-as (external|internal|ASNUM)
+                #
+                # and adding
+                #     neighbor swp1 interface
+                #     neighbor swp1 remote-as (external|internal|ASNUM)
+                #     neighbor swp1 capability extended-nexthop
+                #
+                # If so then chop the del line and the corresponding add lines
+                re_swpx_int_remoteas = re.search(
+                    "neighbor (\S+) interface remote-as (\S+)", line
+                )
+                re_swpx_int_v6only_remoteas = re.search(
+                    "neighbor (\S+) interface v6only remote-as (\S+)", line
+                )
+
+                if re_swpx_int_remoteas or re_swpx_int_v6only_remoteas:
+                    swpx_interface = None
+                    swpx_remoteas = None
+
+                    if re_swpx_int_remoteas:
+                        swpx = re_swpx_int_remoteas.group(1)
+                        remoteas = re_swpx_int_remoteas.group(2)
+                        swpx_interface = "neighbor %s interface" % swpx
+                    elif re_swpx_int_v6only_remoteas:
+                        swpx = re_swpx_int_v6only_remoteas.group(1)
+                        remoteas = re_swpx_int_v6only_remoteas.group(2)
+                        swpx_interface = "neighbor %s interface v6only" % swpx
+
+                    swpx_remoteas = "neighbor %s remote-as %s" % (swpx, remoteas)
+                    found_add_swpx_interface = line_exist(
+                        lines_to_add, ctx_keys, swpx_interface
+                    )
+                    found_add_swpx_remoteas = line_exist(
+                        lines_to_add, ctx_keys, swpx_remoteas
+                    )
+                    tmp_ctx_keys = tuple(list(ctx_keys))
+
+                    if found_add_swpx_interface and found_add_swpx_remoteas:
+                        deleted = True
+                        lines_to_del_to_del.append((ctx_keys, line))
+                        lines_to_add_to_del.append((ctx_keys, swpx_interface))
+                        lines_to_add_to_del.append((tmp_ctx_keys, swpx_remoteas))
+
+            # We made the 'bgp bestpath as-path multipath-relax' command
+            # automatically assume 'no-as-set' since the lack of this option
+            # caused weird routing problems. When the running config is shown
+            # in releases with this change, the no-as-set keyword is not shown
+            # as it is the default. This causes frr-reload to unnecessarily
+            # unapply this option only to apply it back again, causing
+            # unnecessary session resets.
+            if "multipath-relax" in line:
+                re_asrelax_new = re.search(
+                    "^bgp\s+bestpath\s+as-path\s+multipath-relax$", line
+                )
+                old_asrelax_cmd = "bgp bestpath as-path multipath-relax no-as-set"
+                found_asrelax_old = line_exist(lines_to_add, ctx_keys, old_asrelax_cmd)
+
+                if re_asrelax_new and found_asrelax_old:
+                    deleted = True
+                    lines_to_del_to_del.append((ctx_keys, line))
+                    lines_to_add_to_del.append((ctx_keys, old_asrelax_cmd))
+
+            # If we are modifying the BGP table-map we need to avoid a del/add
+            # and instead modify the table-map in place via an add.  This is
+            # needed to avoid installing all routes in the RIB the second the
+            # 'no table-map' is issued.
+            if line.startswith("table-map"):
+                found_table_map = line_exist(lines_to_add, ctx_keys, "table-map", False)
+
+                if found_table_map:
+                    lines_to_del_to_del.append((ctx_keys, line))
+
+        # More old-to-new config handling. ip import-table no longer accepts
+        # distance, but we honor the old syntax. But 'show running' shows only
+        # the new syntax. This causes an unnecessary 'no import-table' followed
+        # by the same old 'ip import-table' which causes perturbations in
+        # announced routes leading to traffic blackholes. Fix this issue.
+        re_importtbl = re.search("^ip\s+import-table\s+(\d+)$", ctx_keys[0])
+        if re_importtbl:
+            table_num = re_importtbl.group(1)
+            for ctx in lines_to_add:
+                if ctx[0][0].startswith("ip import-table %s distance" % table_num):
+                    lines_to_del_to_del.append(
+                        (("ip import-table %s" % table_num,), None)
+                    )
+                    lines_to_add_to_del.append((ctx[0], None))
+
+        # ip/ipv6 prefix-lists and access-lists can be specified without a seq
+        # number.  However, the running config always adds 'seq x', where x is
+        # a number incremented by 5 for every element of the prefix/access
+        # list.  So, ignore such lines as well. Sample prefix-list and
+        # acces-list lines:
+        #      ip prefix-list PR-TABLE-2 seq 5 permit 20.8.2.0/24 le 32
+        #      ip prefix-list PR-TABLE-2 seq 10 permit 20.8.2.0/24 le 32
+        #      ipv6 prefix-list vrfdev6-12 permit 2000:9:2::/64 gt 64
+        #      access-list FOO seq 5 permit 2.2.2.2/32
+        #      ipv6 access-list BAR seq 5 permit 2:2:2::2/128
+        re_acl_pfxlst = re.search(
+            "^(ip |ipv6 |)(prefix-list|access-list)(\s+\S+\s+)(seq \d+\s+)(permit|deny)(.*)$",
+            ctx_keys[0],
+        )
+        if re_acl_pfxlst:
+            found = False
+            tmpline = (
+                re_acl_pfxlst.group(1)
+                + re_acl_pfxlst.group(2)
+                + re_acl_pfxlst.group(3)
+                + re_acl_pfxlst.group(5)
+                + re_acl_pfxlst.group(6)
+            )
+            for ctx in lines_to_add:
+                if ctx[0][0] == tmpline:
+                    lines_to_del_to_del.append((ctx_keys, None))
+                    lines_to_add_to_del.append(((tmpline,), None))
+                    found = True
+            # If prefix-lists or access-lists are being deleted and not added
+            # (see comment above), add command with 'no' to lines_to_add and
+            # remove from lines_to_del to improve scaling performance.
+            if found is False:
+                add_cmd = ("no " + ctx_keys[0],)
+                lines_to_add.append((add_cmd, None))
+                lines_to_del_to_del.append((ctx_keys, None))
+
+        # bgp community-list, large-community-list, extcommunity-list can be
+        # specified without a seq number. However, the running config always
+        # adds `seq X` (sequence number). So, ignore such lines as well.
+        # Examples:
+        #      bgp community-list standard clist seq 5 permit 222:213
+        #      bgp large-community-list standard llist seq 5 permit 65001:65001:1
+        #      bgp extcommunity-list standard elist seq 5 permit soo 123:123
+        re_bgp_lists = re.search(
+            "^(bgp )(community-list|large-community-list|extcommunity-list)(\s+\S+\s+)(\S+\s+)(seq \d+\s+)(permit|deny)(.*)$",
+            ctx_keys[0],
+        )
+        if re_bgp_lists:
+            found = False
+            tmpline = (
+                re_bgp_lists.group(1)
+                + re_bgp_lists.group(2)
+                + re_bgp_lists.group(3)
+                + re_bgp_lists.group(4)
+                + re_bgp_lists.group(6)
+                + re_bgp_lists.group(7)
+            )
+            for ctx in lines_to_add:
+                if ctx[0][0] == tmpline:
+                    lines_to_del_to_del.append((ctx_keys, None))
+                    lines_to_add_to_del.append(((tmpline,), None))
+                    found = True
+            if found is False:
+                add_cmd = ("no " + ctx_keys[0],)
+                lines_to_add.append((add_cmd, None))
+                lines_to_del_to_del.append((ctx_keys, None))
+
+        if (
+            len(ctx_keys) == 3
+            and ctx_keys[0].startswith("router bgp")
+            and ctx_keys[1] == "address-family l2vpn evpn"
+            and ctx_keys[2].startswith("vni")
+        ):
+
+            re_route_target = (
+                re.search("^route-target import (.*)$", line)
+                if line is not None
+                else False
+            )
+
+            if re_route_target:
+                rt = re_route_target.group(1).strip()
+                route_target_import_line = line
+                route_target_export_line = "route-target export %s" % rt
+                route_target_both_line = "route-target both %s" % rt
+
+                found_route_target_export_line = line_exist(
+                    lines_to_del, ctx_keys, route_target_export_line
+                )
+                found_route_target_both_line = line_exist(
+                    lines_to_add, ctx_keys, route_target_both_line
+                )
+
+                # If the running configs has
+                #     route-target import 1:1
+                #     route-target export 1:1
+                # and the config we are reloading against has
+                #     route-target both 1:1
+                # then we can ignore deleting the import/export and ignore adding the 'both'
+                if found_route_target_export_line and found_route_target_both_line:
+                    lines_to_del_to_del.append((ctx_keys, route_target_import_line))
+                    lines_to_del_to_del.append((ctx_keys, route_target_export_line))
+                    lines_to_add_to_del.append((ctx_keys, route_target_both_line))
+
+        # Deleting static routes under a vrf can lead to time-outs if each is sent
+        # as separate vtysh -c commands. Change them from being in lines_to_del and
+        # put the "no" form in lines_to_add
+        if ctx_keys[0].startswith("vrf ") and line:
+            if line.startswith("ip route") or line.startswith("ipv6 route"):
+                add_cmd = "no " + line
+                lines_to_add.append((ctx_keys, add_cmd))
+                lines_to_del_to_del.append((ctx_keys, line))
+
+        if not deleted:
+            found_add_line = line_exist(lines_to_add, ctx_keys, line)
+
+            if found_add_line:
+                lines_to_del_to_del.append((ctx_keys, line))
+                lines_to_add_to_del.append((ctx_keys, line))
+            else:
+                # We have commands that used to be displayed in the global part
+                # of 'router bgp' that are now displayed under 'address-family ipv4 unicast'
+                #
+                # # old way
+                # router bgp 64900
+                #   neighbor ISL advertisement-interval 0
+                #
+                # vs.
+                #
+                # # new way
+                # router bgp 64900
+                #   address-family ipv4 unicast
+                #     neighbor ISL advertisement-interval 0
+                #
+                # Look to see if we are deleting it in one format just to add it back in the other
+                if (
+                    ctx_keys[0].startswith("router bgp")
+                    and len(ctx_keys) > 1
+                    and ctx_keys[1] == "address-family ipv4 unicast"
+                ):
+                    tmp_ctx_keys = list(ctx_keys)[:-1]
+                    tmp_ctx_keys = tuple(tmp_ctx_keys)
+
+                    found_add_line = line_exist(lines_to_add, tmp_ctx_keys, line)
+
+                    if found_add_line:
+                        lines_to_del_to_del.append((ctx_keys, line))
+                        lines_to_add_to_del.append((tmp_ctx_keys, line))
+
+    for (ctx_keys, line) in lines_to_del_to_del:
+        try:
+            lines_to_del.remove((ctx_keys, line))
+        except ValueError:
+            pass
+
+    for (ctx_keys, line) in lines_to_add_to_del:
+        try:
+            lines_to_add.remove((ctx_keys, line))
+        except ValueError:
+            pass
+
+
+    return (lines_to_add, lines_to_del)
+
+
+def ignore_unconfigurable_lines(lines_to_add, lines_to_del):
+    """
+    There are certain commands that cannot be removed.  Remove
+    those commands from lines_to_del.
+    """
+    lines_to_del_to_del = []
+
+    for (ctx_keys, line) in lines_to_del:
+
+        # The integrated-vtysh-config one is technically "no"able but if we did
+        # so frr-reload would stop working so do not let the user shoot
+        # themselves in the foot by removing this.
+        if any(
+            [
+                ctx_keys[0].startswith(x)
+                for x in [
+                    "agentx",
+                    "frr version",
+                    "frr defaults",
+                    "username",
+                    "password",
+                    "line vty",
+                    "service integrated-vtysh-config",
+                ]
+            ]
+        ):
+            log.info('"%s" cannot be removed' % (ctx_keys[-1],))
+            lines_to_del_to_del.append((ctx_keys, line))
+
+    for (ctx_keys, line) in lines_to_del_to_del:
+        lines_to_del.remove((ctx_keys, line))
+
+    return (lines_to_add, lines_to_del)
+
+
+def compare_context_objects(newconf, running):
+    """
+    Create a context diff for the two specified contexts
+    """
+
+    # Compare the two Config objects to find the lines that we need to add/del
+    lines_to_add = []
+    lines_to_del = []
+    pollist_to_del = []
+    seglist_to_del = []
+    pceconf_to_del = []
+    pcclist_to_del = []
+    candidates_to_add = []
+    delete_bgpd = False
+
+    # Find contexts that are in newconf but not in running
+    # Find contexts that are in running but not in newconf
+    for (running_ctx_keys, running_ctx) in iteritems(running.contexts):
+
+        if running_ctx_keys not in newconf.contexts:
+
+            # We check that the len is 1 here so that we only look at ('router bgp 10')
+            # and not ('router bgp 10', 'address-family ipv4 unicast'). The
+            # latter could cause a false delete_bgpd positive if ipv4 unicast is in
+            # running but not in newconf.
+            if "router bgp" in running_ctx_keys[0] and len(running_ctx_keys) == 1:
+                delete_bgpd = True
+                lines_to_del.append((running_ctx_keys, None))
+
+            # We cannot do 'no interface' or 'no vrf' in FRR, and so deal with it
+            elif running_ctx_keys[0].startswith("interface") or running_ctx_keys[
+                0
+            ].startswith("vrf"):
+                for line in running_ctx.lines:
+                    lines_to_del.append((running_ctx_keys, line))
+
+            # If this is an address-family under 'router bgp' and we are already deleting the
+            # entire 'router bgp' context then ignore this sub-context
+            elif (
+                "router bgp" in running_ctx_keys[0]
+                and len(running_ctx_keys) > 1
+                and delete_bgpd
+            ):
+                continue
+
+            # Delete an entire vni sub-context under "address-family l2vpn evpn"
+            elif (
+                "router bgp" in running_ctx_keys[0]
+                and len(running_ctx_keys) > 2
+                and running_ctx_keys[1].startswith("address-family l2vpn evpn")
+                and running_ctx_keys[2].startswith("vni ")
+            ):
+                lines_to_del.append((running_ctx_keys, None))
+
+            elif (
+                "router bgp" in running_ctx_keys[0]
+                and len(running_ctx_keys) > 1
+                and running_ctx_keys[1].startswith("address-family")
+            ):
+                # There's no 'no address-family' support and so we have to
+                # delete each line individually again
+                for line in running_ctx.lines:
+                    lines_to_del.append((running_ctx_keys, line))
+
+            # Some commands can happen at higher counts that make
+            # doing vtysh -c inefficient (and can time out.)  For
+            # these commands, instead of adding them to lines_to_del,
+            # add the "no " version to lines_to_add.
+            elif running_ctx_keys[0].startswith("ip route") or running_ctx_keys[
+                0
+            ].startswith("ipv6 route"):
+                add_cmd = ("no " + running_ctx_keys[0],)
+                lines_to_add.append((add_cmd, None))
+
+            # if this an interface sub-subcontext in an address-family block in ldpd and
+            # we are already deleting the whole context, then ignore this
+            elif (
+                len(running_ctx_keys) > 2
+                and running_ctx_keys[0].startswith("mpls ldp")
+                and running_ctx_keys[1].startswith("address-family")
+                and (running_ctx_keys[:2], None) in lines_to_del
+            ):
+                continue
+
+            # same thing for a pseudowire sub-context inside an l2vpn context
+            elif (
+                len(running_ctx_keys) > 1
+                and running_ctx_keys[0].startswith("l2vpn")
+                and running_ctx_keys[1].startswith("member pseudowire")
+                and (running_ctx_keys[:1], None) in lines_to_del
+            ):
+                continue
+
+            # Segment routing and traffic engineering never need to be deleted
+            elif (
+                running_ctx_keys[0].startswith("segment-routing")
+                and len(running_ctx_keys) < 3
+            ):
+                continue
+
+            # Neither the pcep command
+            elif (
+                len(running_ctx_keys) == 3
+                and running_ctx_keys[0].startswith("segment-routing")
+                and running_ctx_keys[2].startswith("pcep")
+            ):
+                continue
+
+            # Segment lists can only be deleted after we removed all the candidate paths that
+            # use them, so add them to a separate array that is going to be appended at the end
+            elif (
+                len(running_ctx_keys) == 3
+                and running_ctx_keys[0].startswith("segment-routing")
+                and running_ctx_keys[2].startswith("segment-list")
+            ):
+                seglist_to_del.append((running_ctx_keys, None))
+
+            # Policies must be deleted after there candidate path, to be sure
+            # we add them to a separate array that is going to be appended at the end
+            elif (
+                len(running_ctx_keys) == 3
+                and running_ctx_keys[0].startswith("segment-routing")
+                and running_ctx_keys[2].startswith("policy")
+            ):
+                pollist_to_del.append((running_ctx_keys, None))
+
+            # pce-config must be deleted after the pce, to be sure we add them
+            # to a separate array that is going to be appended at the end
+            elif (
+                len(running_ctx_keys) >= 4
+                and running_ctx_keys[0].startswith("segment-routing")
+                and running_ctx_keys[3].startswith("pce-config")
+            ):
+                pceconf_to_del.append((running_ctx_keys, None))
+
+            # pcc must be deleted after the pce and pce-config too
+            elif (
+                len(running_ctx_keys) >= 4
+                and running_ctx_keys[0].startswith("segment-routing")
+                and running_ctx_keys[3].startswith("pcc")
+            ):
+                pcclist_to_del.append((running_ctx_keys, None))
+
+            # Non-global context
+            elif running_ctx_keys and not any(
+                "address-family" in key for key in running_ctx_keys
+            ):
+                lines_to_del.append((running_ctx_keys, None))
+
+            elif running_ctx_keys and not any("vni" in key for key in running_ctx_keys):
+                lines_to_del.append((running_ctx_keys, None))
+
+            # Global context
+            else:
+                for line in running_ctx.lines:
+                    lines_to_del.append((running_ctx_keys, line))
+
+    # if we have some policies commands to delete, append them to lines_to_del
+    if len(pollist_to_del) > 0:
+        lines_to_del.extend(pollist_to_del)
+
+    # if we have some segment list commands to delete, append them to lines_to_del
+    if len(seglist_to_del) > 0:
+        lines_to_del.extend(seglist_to_del)
+
+    # if we have some pce list commands to delete, append them to lines_to_del
+    if len(pceconf_to_del) > 0:
+        lines_to_del.extend(pceconf_to_del)
+
+    # if we have some pcc list commands to delete, append them to lines_to_del
+    if len(pcclist_to_del) > 0:
+        lines_to_del.extend(pcclist_to_del)
+
+    # Find the lines within each context to add
+    # Find the lines within each context to del
+    for (newconf_ctx_keys, newconf_ctx) in iteritems(newconf.contexts):
+
+        if newconf_ctx_keys in running.contexts:
+            running_ctx = running.contexts[newconf_ctx_keys]
+
+            for line in newconf_ctx.lines:
+                if line not in running_ctx.dlines:
+
+                    # candidate paths can only be added after the policy and segment list,
+                    # so add them to a separate array that is going to be appended at the end
+                    if (
+                        len(newconf_ctx_keys) == 3
+                        and newconf_ctx_keys[0].startswith("segment-routing")
+                        and newconf_ctx_keys[2].startswith("policy ")
+                        and line.startswith("candidate-path ")
+                    ):
+                        candidates_to_add.append((newconf_ctx_keys, line))
+
+                    else:
+                        lines_to_add.append((newconf_ctx_keys, line))
+
+            for line in running_ctx.lines:
+                if line not in newconf_ctx.dlines:
+                    lines_to_del.append((newconf_ctx_keys, line))
+
+    for (newconf_ctx_keys, newconf_ctx) in iteritems(newconf.contexts):
+
+        if newconf_ctx_keys not in running.contexts:
+
+            # candidate paths can only be added after the policy and segment list,
+            # so add them to a separate array that is going to be appended at the end
+            if (
+                len(newconf_ctx_keys) == 4
+                and newconf_ctx_keys[0].startswith("segment-routing")
+                and newconf_ctx_keys[3].startswith("candidate-path")
+            ):
+                candidates_to_add.append((newconf_ctx_keys, None))
+                for line in newconf_ctx.lines:
+                    candidates_to_add.append((newconf_ctx_keys, line))
+
+            else:
+                lines_to_add.append((newconf_ctx_keys, None))
+
+                for line in newconf_ctx.lines:
+                    lines_to_add.append((newconf_ctx_keys, line))
+
+    # if we have some candidate paths commands to add, append them to lines_to_add
+    if len(candidates_to_add) > 0:
+        lines_to_add.extend(candidates_to_add)
+
+    (lines_to_add, lines_to_del) = check_for_exit_vrf(lines_to_add, lines_to_del)
+    (lines_to_add, lines_to_del) = ignore_delete_re_add_lines(
+        lines_to_add, lines_to_del
+    )
+    (lines_to_add, lines_to_del) = delete_move_lines(lines_to_add, lines_to_del)
+    (lines_to_add, lines_to_del) = ignore_unconfigurable_lines(
+        lines_to_add, lines_to_del
+    )
+
+    return (lines_to_add, lines_to_del)
+
+
+if __name__ == "__main__":
+    # Command line options
+    parser = argparse.ArgumentParser(
+        description="Dynamically apply diff in frr configs"
+    )
+    parser.add_argument(
+        "--input", help='Read running config from file instead of "show running"'
+    )
+    group = parser.add_mutually_exclusive_group(required=True)
+    group.add_argument(
+        "--reload", action="store_true", help="Apply the deltas", default=False
+    )
+    group.add_argument(
+        "--test", action="store_true", help="Show the deltas", default=False
+    )
+    level_group = parser.add_mutually_exclusive_group()
+    level_group.add_argument(
+        "--debug",
+        action="store_true",
+        help="Enable debugs (synonym for --log-level=debug)",
+        default=False,
+    )
+    level_group.add_argument(
+        "--log-level",
+        help="Log level",
+        default="info",
+        choices=("critical", "error", "warning", "info", "debug"),
+    )
+    parser.add_argument(
+        "--stdout", action="store_true", help="Log to STDOUT", default=False
+    )
+    parser.add_argument(
+        "--pathspace",
+        "-N",
+        metavar="NAME",
+        help="Reload specified path/namespace",
+        default=None,
+    )
+    parser.add_argument("filename", help="Location of new frr config file")
+    parser.add_argument(
+        "--overwrite",
+        action="store_true",
+        help="Overwrite frr.conf with running config output",
+        default=False,
+    )
+    parser.add_argument(
+        "--bindir", help="path to the vtysh executable", default="/usr/bin"
+    )
+    parser.add_argument(
+        "--confdir", help="path to the daemon config files", default="/etc/frr"
+    )
+    parser.add_argument(
+        "--rundir", help="path for the temp config file", default="/var/run/frr"
+    )
+    parser.add_argument(
+        "--vty_socket",
+        help="socket to be used by vtysh to connect to the daemons",
+        default=None,
+    )
+    parser.add_argument(
+        "--daemon", help="daemon for which want to replace the config", default=""
+    )
+    parser.add_argument(
+        "--test-reset",
+        action="store_true",
+        help="Used by topotest to not delete debug or log file commands",
+    )
+
+    args = parser.parse_args()
+
+    # Logging
+    # For --test log to stdout
+    # For --reload log to /var/log/frr/frr-reload.log
+    if args.test or args.stdout:
+        logging.basicConfig(format="%(asctime)s %(levelname)5s: %(message)s")
+
+        # Color the errors and warnings in red
+        logging.addLevelName(
+            logging.ERROR, "\033[91m  %s\033[0m" % logging.getLevelName(logging.ERROR)
+        )
+        logging.addLevelName(
+            logging.WARNING, "\033[91m%s\033[0m" % logging.getLevelName(logging.WARNING)
+        )
+
+    elif args.reload:
+        if not os.path.isdir("/var/log/frr/"):
+            os.makedirs("/var/log/frr/", mode=0o0755)
+
+        logging.basicConfig(
+            filename="/var/log/frr/frr-reload.log",
+            format="%(asctime)s %(levelname)5s: %(message)s",
+        )
+
+    # argparse should prevent this from happening but just to be safe...
+    else:
+        raise Exception("Must specify --reload or --test")
+    log = logging.getLogger(__name__)
+
+    if args.debug:
+        log.setLevel(logging.DEBUG)
+    else:
+        log.setLevel(args.log_level.upper())
+
+    if args.reload and not args.stdout:
+        # Additionally send errors and above to STDOUT, with no metadata,
+        # when we are logging to a file. This specifically does not follow
+        # args.log_level, and is analagous to behaviour in earlier versions
+        # which additionally logged most errors using print().
+
+        stdout_hdlr = logging.StreamHandler(sys.stdout)
+        stdout_hdlr.setLevel(logging.ERROR)
+        stdout_hdlr.setFormatter(logging.Formatter())
+        log.addHandler(stdout_hdlr)
+
+    # Verify the new config file is valid
+    if not os.path.isfile(args.filename):
+        log.error("Filename %s does not exist" % args.filename)
+        sys.exit(1)
+
+    if not os.path.getsize(args.filename):
+        log.error("Filename %s is an empty file" % args.filename)
+        sys.exit(1)
+
+    # Verify that confdir is correct
+    if not os.path.isdir(args.confdir):
+        log.error("Confdir %s is not a valid path" % args.confdir)
+        sys.exit(1)
+
+    # Verify that bindir is correct
+    if not os.path.isdir(args.bindir) or not os.path.isfile(args.bindir + "/vtysh"):
+        log.error("Bindir %s is not a valid path to vtysh" % args.bindir)
+        sys.exit(1)
+
+    # verify that the vty_socket, if specified, is valid
+    if args.vty_socket and not os.path.isdir(args.vty_socket):
+        log.error("vty_socket %s is not a valid path" % args.vty_socket)
+        sys.exit(1)
+
+    # verify that the daemon, if specified, is valid
+    if args.daemon and args.daemon not in [
+        "zebra",
+        "bgpd",
+        "fabricd",
+        "isisd",
+        "ospf6d",
+        "ospfd",
+        "pbrd",
+        "pimd",
+        "pim6d",
+        "ripd",
+        "ripngd",
+        "sharpd",
+        "staticd",
+        "vrrpd",
+        "ldpd",
+        "pathd",
+        "bfdd",
+        "eigrpd",
+    ]:
+        msg = "Daemon %s is not a valid option for 'show running-config'" % args.daemon
+        print(msg)
+        log.error(msg)
+        sys.exit(1)
+
+    vtysh = Vtysh(args.bindir, args.confdir, args.vty_socket, args.pathspace)
+
+    # Verify that 'service integrated-vtysh-config' is configured
+    if args.pathspace:
+        vtysh_filename = args.confdir + "/" + args.pathspace + "/vtysh.conf"
+    else:
+        vtysh_filename = args.confdir + "/vtysh.conf"
+    service_integrated_vtysh_config = True
+
+    if os.path.isfile(vtysh_filename):
+        with open(vtysh_filename, "r") as fh:
+            for line in fh.readlines():
+                line = line.strip()
+
+                if line == "no service integrated-vtysh-config":
+                    service_integrated_vtysh_config = False
+                    break
+
+    if not args.test and not service_integrated_vtysh_config and not args.daemon:
+        log.error(
+            "'service integrated-vtysh-config' is not configured, this is required for 'service frr reload'"
+        )
+        sys.exit(1)
+
+    log.info('Called via "%s"', str(args))
+
+    # Create a Config object from the config generated by newconf
+    newconf = Config(vtysh)
+    try:
+        newconf.load_from_file(args.filename)
+        reload_ok = True
+    except VtyshException as ve:
+        log.error("vtysh failed to process new configuration: {}".format(ve))
+        reload_ok = False
+
+    if args.test:
+
+        # Create a Config object from the running config
+        running = Config(vtysh)
+
+        if args.input:
+            running.load_from_file(args.input)
+        else:
+            running.load_from_show_running(args.daemon)
+
+        (lines_to_add, lines_to_del) = compare_context_objects(newconf, running)
+
+        if lines_to_del:
+            if not args.test_reset:
+                print("\nLines To Delete")
+                print("===============")
+
+            for (ctx_keys, line) in lines_to_del:
+
+                if line == "!":
+                    continue
+
+                nolines = lines_to_config(ctx_keys, line, True)
+
+                if args.test_reset:
+                    # For topotests the original code stripped the lines, and ommitted blank lines
+                    # after, do that here
+                    nolines = [x.strip() for x in nolines]
+                    # For topotests leave these lines in (don't delete them)
+                    # [chopps: why is "log file" more special than other "log" commands?]
+                    nolines = [
+                        x for x in nolines if "debug" not in x and "log file" not in x
+                    ]
+                    if not nolines:
+                        continue
+
+                cmd = "\n".join(nolines)
+                print(cmd)
+
+        if lines_to_add:
+            if not args.test_reset:
+                print("\nLines To Add")
+                print("============")
+
+            for (ctx_keys, line) in lines_to_add:
+
+                if line == "!":
+                    continue
+
+                lines = lines_to_config(ctx_keys, line, False)
+
+                if args.test_reset:
+                    # For topotests the original code stripped the lines, and ommitted blank lines
+                    # after, do that here
+                    lines = [x.strip() for x in lines if x.strip()]
+                    if not lines:
+                        continue
+
+                cmd = "\n".join(lines)
+                print(cmd)
+
+    elif args.reload:
+        lines_to_configure = []
+
+        # We will not be able to do anything, go ahead and exit(1)
+        if not vtysh.is_config_available() or not reload_ok:
+            sys.exit(1)
+
+        log.debug("New Frr Config\n%s", newconf.get_lines())
+
+        # This looks a little odd but we have to do this twice...here is why
+        # If the user had this running bgp config:
+        #
+        # router bgp 10
+        #  neighbor 1.1.1.1 remote-as 50
+        #  neighbor 1.1.1.1 route-map FOO out
+        #
+        # and this config in the newconf config file
+        #
+        # router bgp 10
+        #  neighbor 1.1.1.1 remote-as 999
+        #  neighbor 1.1.1.1 route-map FOO out
+        #
+        #
+        # Then the script will do
+        # - no neighbor 1.1.1.1 remote-as 50
+        # - neighbor 1.1.1.1 remote-as 999
+        #
+        # The problem is the "no neighbor 1.1.1.1 remote-as 50" will also remove
+        # the "neighbor 1.1.1.1 route-map FOO out" line...so we compare the
+        # configs again to put this line back.
+
+        # There are many keywords in FRR that can only appear one time under
+        # a context, take "bgp router-id" for example. If the config that we are
+        # reloading against has the following:
+        #
+        # router bgp 10
+        #   bgp router-id 1.1.1.1
+        #   bgp router-id 2.2.2.2
+        #
+        # The final config needs to contain "bgp router-id 2.2.2.2". On the
+        # first pass we will add "bgp router-id 2.2.2.2" but then on the second
+        # pass we will see that "bgp router-id 1.1.1.1" is missing and add that
+        # back which cancels out the "bgp router-id 2.2.2.2". The fix is for the
+        # second pass to include all of the "adds" from the first pass.
+        lines_to_add_first_pass = []
+
+        for x in range(2):
+            running = Config(vtysh)
+            running.load_from_show_running(args.daemon)
+            log.debug("Running Frr Config (Pass #%d)\n%s", x, running.get_lines())
+
+            (lines_to_add, lines_to_del) = compare_context_objects(newconf, running)
+
+            if x == 0:
+                lines_to_add_first_pass = lines_to_add
+            else:
+                lines_to_add.extend(lines_to_add_first_pass)
+
+            # Only do deletes on the first pass. The reason being if we
+            # configure a bgp neighbor via "neighbor swp1 interface" FRR
+            # will automatically add:
+            #
+            # interface swp1
+            #  ipv6 nd ra-interval 10
+            #  no ipv6 nd suppress-ra
+            # !
+            #
+            # but those lines aren't in the config we are reloading against so
+            # on the 2nd pass they will show up in lines_to_del.  This could
+            # apply to other scenarios as well where configuring FOO adds BAR
+            # to the config.
+            if lines_to_del and x == 0:
+                for (ctx_keys, line) in lines_to_del:
+
+                    if line == "!":
+                        continue
+
+                    # 'no' commands are tricky, we can't just put them in a file and
+                    # vtysh -f that file. See the next comment for an explanation
+                    # of their quirks
+                    cmd = lines_to_config(ctx_keys, line, True)
+                    original_cmd = cmd
+
+                    # Some commands in frr are picky about taking a "no" of the entire line.
+                    # OSPF is bad about this, you can't "no" the entire line, you have to "no"
+                    # only the beginning. If we hit one of these command an exception will be
+                    # thrown.  Catch it and remove the last '-c', 'FOO' from cmd and try again.
+                    #
+                    # Example:
+                    # frr(config-if)# ip ospf authentication message-digest 1.1.1.1
+                    # frr(config-if)# no ip ospf authentication message-digest 1.1.1.1
+                    #  % Unknown command.
+                    # frr(config-if)# no ip ospf authentication message-digest
+                    #  % Unknown command.
+                    # frr(config-if)# no ip ospf authentication
+                    # frr(config-if)#
+
+                    stdouts = []
+                    while True:
+                        try:
+                            vtysh(["configure"] + cmd, stdouts)
+
+                        except VtyshException:
+
+                            # - Pull the last entry from cmd (this would be
+                            #   'no ip ospf authentication message-digest 1.1.1.1' in
+                            #   our example above
+                            # - Split that last entry by whitespace and drop the last word
+                            log.info("Failed to execute %s", " ".join(cmd))
+                            last_arg = cmd[-1].split(" ")
+
+                            if len(last_arg) <= 2:
+                                log.error(
+                                    '"%s" we failed to remove this command',
+                                    " -- ".join(original_cmd),
+                                )
+                                # Log first error msg for original_cmd
+                                if stdouts:
+                                    log.error(stdouts[0])
+                                reload_ok = False
+                                break
+
+                            new_last_arg = last_arg[0:-1]
+                            cmd[-1] = " ".join(new_last_arg)
+                        else:
+                            log.info('Executed "%s"', " ".join(cmd))
+                            break
+
+            if lines_to_add:
+                lines_to_configure = []
+
+                for (ctx_keys, line) in lines_to_add:
+
+                    if line == "!":
+                        continue
+
+                    # Don't run "no" commands twice since they can error
+                    # out the second time due to first deletion
+                    if x == 1 and ctx_keys[0].startswith("no "):
+                        continue
+
+                    cmd = "\n".join(lines_to_config(ctx_keys, line, False)) + "\n"
+                    lines_to_configure.append(cmd)
+
+                if lines_to_configure:
+                    random_string = "".join(
+                        random.SystemRandom().choice(
+                            string.ascii_uppercase + string.digits
+                        )
+                        for _ in range(6)
+                    )
+
+                    filename = args.rundir + "/reload-%s.txt" % random_string
+                    log.info("%s content\n%s" % (filename, pformat(lines_to_configure)))
+
+                    with open(filename, "w") as fh:
+                        for line in lines_to_configure:
+                            fh.write(line + "\n")
+
+                    try:
+                        vtysh.exec_file(filename)
+                    except VtyshException as e:
+                        log.warning("frr-reload.py failed due to\n%s" % e.args)
+                        reload_ok = False
+                    os.unlink(filename)
+
+        # Make these changes persistent
+        target = str(args.confdir + "/frr.conf")
+        if args.overwrite or (not args.daemon and args.filename != target):
+            vtysh("write")
+
+    if not reload_ok:
+        sys.exit(1)