diff --git a/configure.ac b/configure.ac

index 93520a80..d01ce6e4 100644

--- a/configure.ac

+++ b/configure.ac

@@ -712,6 +712,7 @@ AC_CONFIG_FILES([

 	tools/rpcgen/Makefile

 	tools/mountstats/Makefile

 	tools/nfs-iostat/Makefile

+	tools/rpcctl/Makefile

 	tools/nfsdclnts/Makefile

 	tools/nfsconf/Makefile

 	tools/nfsdclddb/Makefile

diff --git a/tools/Makefile.am b/tools/Makefile.am

index 9b4b0803..c3feabbe 100644

--- a/tools/Makefile.am

+++ b/tools/Makefile.am

@@ -12,6 +12,6 @@ if CONFIG_NFSDCLD

 OPTDIRS += nfsdclddb

 endif

-SUBDIRS = locktest rpcdebug nlmtest mountstats nfs-iostat nfsdclnts $(OPTDIRS)

+SUBDIRS = locktest rpcdebug nlmtest mountstats nfs-iostat rpcctl nfsdclnts $(OPTDIRS)

 MAINTAINERCLEANFILES = Makefile.in

diff --git a/tools/rpcctl/Makefile.am b/tools/rpcctl/Makefile.am

new file mode 100644

index 00000000..33fb431f

--- /dev/null

+++ b/tools/rpcctl/Makefile.am

@@ -0,0 +1,13 @@

+## Process this file with automake to produce Makefile.in

+PYTHON_FILES =  rpcctl.py

+

+man8_MANS = rpcctl.man

+

+EXTRA_DIST = $(man8_MANS) $(PYTHON_FILES)

+

+all-local: $(PYTHON_FILES)

+

+install-data-hook:

+	$(INSTALL) -m 755 rpcctl.py $(DESTDIR)$(sbindir)/rpcctl

+

+MAINTAINERCLEANFILES=Makefile.in

diff --git a/tools/rpcctl/rpcctl.man b/tools/rpcctl/rpcctl.man

new file mode 100644

index 00000000..b87ba0df

--- /dev/null

+++ b/tools/rpcctl/rpcctl.man

@@ -0,0 +1,67 @@

+.\"

+.\" rpcctl(8)

+.\"

+.TH rpcctl 8 "15 Feb 2022"

+.SH NAME

+rpcctl \- Displays SunRPC connection information

+.SH SYNOPSIS

+.nf

+.BR rpcctl " [ \fB\-h \fR| \fB\-\-help \fR] { \fBclient \fR| \fBswitch \fR| \fBxprt \fR}"

+.P

+.BR "rpcctl client" " \fR[ \fB\-h \fR| \fB\-\-help \fR] { \fBshow \fR}"

+.BR "rpcctl client show " "\fR[ \fB\-h \f| \fB\-\-help \fR] [ \fIXPRT \fR]"

+.P

+.BR "rpcctl switch" " \fR[ \fB\-h \fR| \fB\-\-help \fR] { \fBset \fR| \fBshow \fR}"

+.BR "rpcctl switch set" " \fR[ \fB\-h \fR| \fB\-\-help \fR] \fISWITCH \fBdstaddr \fINEWADDR"

+.BR "rpcctl switch show" " \fR[ \fB\-h \fR| \fB\-\-help \fR] [ \fISWITCH \fR]"

+.P

+.BR "rpcctl xprt" " \fR[ \fB\-h \fR| \fB\-\-help \fR] { \fBremove \fR| \fBset \fR| \fBshow \fR}"

+.BR "rpcctl xprt remove" " \fR[ \fB\-h \fR| \fB\-\-help \fR] \fIXPRT"

+.BR "rpcctl xprt set" " \fR[ \fB\-h \fR| \fB\-\-help \fR] \fIXPRT \fR{ \fBdstaddr \fINEWADDR \fR| \fBoffline \fR| \fBonline \fR}"

+.BR "rpcctl xprt show" " \fR[ \fB\-h \fR| \fB\-\-help \fR] [ \fIXPRT \fR]"

+.fi

+.SH DESCRIPTION

+.RB "The " rpcctl " command displays information collected in the SunRPC sysfs files about the system's SunRPC objects.

+.P

+.SS rpcctl client \fR- \fBCommands operating on RPC clients

+.IP "\fBshow \fR[ \fICLIENT \fR] \fB(default)"

+Show detailed information about the RPC clients on this system.

+If \fICLIENT \fRwas provided, then only show information about a single RPC client.

+.P

+.SS rpcctl switch \fR- \fBCommands operating on groups of transports

+.IP "\fBset \fISWITCH \fBdstaddr \fINEWADDR"

+Change the destination address of all transports in the \fISWITCH \fRto \fINEWADDR\fR.

+\fINEWADDR \fRcan be an IP address, DNS name, or anything else resolvable by \fBgethostbyname\fR(3).

+.IP "\fBshow \fR[ \fISWITCH \fR] \fB(default)"

+Show detailed information about groups of transports on this system.

+If \fISWITCH \fRwas provided, then only show information about a single transport group.

+.P

+.SS rpcctl xprt \fR- \fBCommands operating on individual transports

+.IP "\fBremove \fIXPRT"

+Removes the specified \fIXPRT \fRfrom the system.

+Note that "main" transports cannot be removed.

+.P

+.IP "\fBset \fIXPRT \fBdstaddr \fINEWADDR"

+Change the destination address of the specified \fIXPRT \fR to \fINEWADDR\fR.

+\fINEWADDR \fRcan be an IP address, DNS name, or anything else resolvable by \fBgethostbyname\fR(3).

+.P

+.IP "\fBset \fIXPRT \fBoffline"

+Sets the specified \fIXPRT\fR's state to offline.

+.P

+.IP "\fBset \fIXPRT \fBonline"

+Sets the specified \fIXPRT\fR's state to online.

+.IP "\fBshow \fR[ \fIXPRT \fR] \fB(default)"

+Show detailed information about this system's transports.

+If \fIXPRT \fRwas provided, then only show information about a single transport.

+.SH EXAMPLES

+.IP "\fBrpcctl switch show switch-2"

+Show details about the RPC switch named "switch-2".

+.IP "\fBrpcctl xprt remove xprt-4"

+Remove the xprt named "xprt-4" from the system.

+.IP "\fBrpcctl xprt set xprt-3 dstaddr https://linux-nfs.org

+Change the dstaddr of the xprt named "xprt-3" to point to linux-nfs.org

+.SH DIRECTORY

+.TP

+.B /sys/kernel/sunrpc/

+.SH AUTHOR

+Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/tools/rpcctl/rpcctl.py b/tools/rpcctl/rpcctl.py

new file mode 100755

index 00000000..b8df556b

--- /dev/null

+++ b/tools/rpcctl/rpcctl.py

@@ -0,0 +1,255 @@

+#!/usr/bin/python3

+import argparse

+import collections

+import errno

+import os

+import pathlib

+import socket

+import sys

+

+with open("/proc/mounts", 'r') as f:

+    mount = [ line.split()[1] for line in f if "sysfs" in line ]

+    if len(mount) == 0:

+        print("ERROR: sysfs is not mounted")

+        sys.exit(1)

+

+sunrpc = pathlib.Path(mount[0]) / "kernel" / "sunrpc"

+if not sunrpc.is_dir():

+    print("ERROR: sysfs does not have sunrpc directory")

+    sys.exit(1)

+

+def read_addr_file(path):

+    try:

+        with open(path, 'r') as f:

+            return f.readline().strip()

+    except:

+        return "(enoent)"

+

+def write_addr_file(path, newaddr):

+    with open(path, 'w') as f:

+        f.write(newaddr)

+    return read_addr_file(path)

+

+def read_info_file(path):

+    res = collections.defaultdict(int)

+    try:

+        with open(path) as info:

+            lines = [ l.split("=", 1) for l in info if "=" in l ]

+            res.update({ key:int(val.strip()) for (key, val) in lines })

+    finally:

+        return res

+

+

+class Xprt:

+    def __init__(self, path):

+        self.path = path

+        self.name = path.stem.rsplit("-", 1)[0]

+        self.type = path.stem.split("-")[2]

+        self.info = read_info_file(path / "xprt_info")

+        self.dstaddr = read_addr_file(path / "dstaddr")

+        self.srcaddr = read_addr_file(path / "srcaddr")

+        self.read_state()

+

+    def __lt__(self, rhs):

+        return self.name < rhs.name

+

+    def _xprt(self):

+        main = ", main" if self.info.get("main_xprt") else ""

+        return f"{self.name}: {self.type}, {self.dstaddr}, " \

+               f"port {self.info['dst_port']}, state <{self.state}>{main}"

+

+    def _src_reqs(self):

+        return f"	Source: {self.srcaddr}, port {self.info['src_port']}, " \

+               f"Requests: {self.info['num_reqs']}"

+

+    def _cong_slots(self):

+        return f"	Congestion: cur {self.info['cur_cong']}, win {self.info['cong_win']}, " \

+               f"Slots: min {self.info['min_num_slots']}, max {self.info['max_num_slots']}"

+

+    def _queues(self):

+        return f"	Queues: binding {self.info['binding_q_len']}, " \

+               f"sending {self.info['sending_q_len']}, pending {self.info['pending_q_len']}, " \

+               f"backlog {self.info['backlog_q_len']}, tasks {self.info['tasks_queuelen']}"

+

+    def __str__(self):

+        if not self.path.exists():

+            return f"{self.name}: has been removed"

+        return "\n".join([self._xprt(), self._src_reqs(),

+                          self._cong_slots(), self._queues() ])

+

+    def read_state(self):

+        if self.path.exists():

+            with open(self.path / "xprt_state") as f:

+                self.state = ','.join(f.readline().split()[1:])

+

+    def small_str(self):

+        main = " [main]" if self.info.get("main_xprt") else ""

+        return f"{self.name}: {self.type}, {self.dstaddr}{main}"

+

+    def set_dstaddr(self, newaddr):

+        self.dstaddr = write_addr_file(self.path / "dstaddr", newaddr)

+

+    def set_state(self, state):

+        with open(self.path / "xprt_state", 'w') as f:

+            f.write(state)

+        self.read_state()

+

+    def add_command(subparser):

+        parser = subparser.add_parser("xprt", help="Commands for individual xprts")

+        parser.set_defaults(func=Xprt.show, xprt=None)

+        subparser = parser.add_subparsers()

+

+        remove = subparser.add_parser("remove", help="Remove an xprt")

+        remove.add_argument("xprt", metavar="XPRT", nargs=1,

+                            help="Name of the xprt to remove")

+        remove.set_defaults(func=Xprt.set_property, property="remove")

+

+        show = subparser.add_parser("show", help="Show xprts")

+        show.add_argument("xprt", metavar="XPRT", nargs='?',

+                          help="Name of a specific xprt to show")

+        show.set_defaults(func=Xprt.show)

+

+        set = subparser.add_parser("set", help="Change an xprt property")

+        set.add_argument("xprt", metavar="XPRT", nargs=1,

+                         help="Name of a specific xprt to modify")

+        subparser = set.add_subparsers(required=True)

+        online = subparser.add_parser("online", help="Set an xprt online")

+        online.set_defaults(func=Xprt.set_property, property="online")

+        offline = subparser.add_parser("offline", help="Set an xprt offline")

+        offline.set_defaults(func=Xprt.set_property, property="offline")

+        dstaddr = subparser.add_parser("dstaddr", help="Change an xprt's dstaddr")

+        dstaddr.add_argument("newaddr", metavar="NEWADDR", nargs=1,

+                             help="The new address for the xprt")

+        dstaddr.set_defaults(func=Xprt.set_property, property="dstaddr")

+

+    def get_by_name(name):

+        glob = f"**/{name}-*" if name else "**/xprt-*"

+        res = [ Xprt(x) for x in (sunrpc / "xprt-switches").glob(glob) ]

+        if name and len(res) == 0:

+            raise FileNotFoundError(errno.ENOENT, os.strerror(errno.ENOENT),

+                                    f"{sunrpc / 'xprt-switches' / glob}")

+        return sorted(res)

+

+    def show(args):

+        for xprt in Xprt.get_by_name(args.xprt):

+            print(xprt)

+

+    def set_property(args):

+        for xprt in Xprt.get_by_name(args.xprt[0]):

+            if args.property == "dstaddr":

+                xprt.set_dstaddr(socket.gethostbyname(args.newaddr[0]))

+            elif args.property == "remove":

+                xprt.set_state("offline")

+                xprt.set_state("remove")

+            else:

+                args.set_state(args.property)

+        print(xprt)

+

+

+class XprtSwitch:

+    def __init__(self, path, sep=":"):

+        self.path = path

+        self.name = path.stem

+        self.info = read_info_file(path / "xprt_switch_info")

+        self.xprts = sorted([ Xprt(p) for p in self.path.iterdir() if p.is_dir() ])

+        self.sep = sep

+

+    def __lt__(self, rhs):

+        return self.name < rhs.name

+

+    def __str__(self):

+        switch =  f"{self.name}{self.sep} " \

+                  f"xprts {self.info['num_xprts']}, " \

+                  f"active {self.info['num_active']}, " \

+                  f"queue {self.info['queue_len']}"

+        xprts = [ f"	{x.small_str()}" for x in self.xprts ]

+        return "\n".join([ switch ] + xprts)

+

+    def add_command(subparser):

+        parser = subparser.add_parser("switch", help="Commands for xprt switches")

+        parser.set_defaults(func=XprtSwitch.show, switch=None)

+        subparser = parser.add_subparsers()

+

+        show = subparser.add_parser("show", help="Show xprt switches")

+        show.add_argument("switch", metavar="SWITCH", nargs='?',

+                          help="Name of a specific switch to show")

+        show.set_defaults(func=XprtSwitch.show)

+

+        set = subparser.add_parser("set", help="Change an xprt switch property")

+        set.add_argument("switch", metavar="SWITCH", nargs=1,

+                         help="Name of a specific xprt switch to modify")

+        subparser = set.add_subparsers(required=True)

+        dstaddr = subparser.add_parser("dstaddr", help="Change an xprt switch's dstaddr")

+        dstaddr.add_argument("newaddr", metavar="NEWADDR", nargs=1,

+                             help="The new address for the xprt switch")

+        dstaddr.set_defaults(func=XprtSwitch.set_property, property="dstaddr")

+

+    def get_by_name(name):

+        xprt_switches = sunrpc / "xprt-switches"

+        if name:

+            return [ XprtSwitch(xprt_switches / name) ]

+        return [ XprtSwitch(f) for f in sorted(xprt_switches.iterdir()) ]

+

+    def show(args):

+        for switch in XprtSwitch.get_by_name(args.switch):

+            print(switch)

+

+    def set_property(args):

+        for switch in XprtSwitch.get_by_name(args.switch[0]):

+            resolved = socket.gethostbyname(args.newaddr[0])

+            for xprt in switch.xprts:

+                xprt.set_dstaddr(resolved)

+        print(switch)

+

+

+class RpcClient:

+    def __init__(self, path):

+        self.path = path

+        self.name = path.stem

+        self.switch = XprtSwitch(path / (path / "switch").readlink(), sep=",")

+

+    def __lt__(self, rhs):

+        return self.name < rhs.name

+

+    def __str__(self):

+        return f"{self.name}: {self.switch}"

+

+    def add_command(subparser):

+        parser = subparser.add_parser("client", help="Commands for rpc clients")

+        parser.set_defaults(func=RpcClient.show, client=None)

+        subparser = parser.add_subparsers()

+

+        show = subparser.add_parser("show", help="Show rpc clients")

+        show.add_argument("client", metavar="CLIENT", nargs='?',

+                          help="Name of a specific rpc client to show")

+        parser.set_defaults(func=RpcClient.show)

+

+    def get_by_name(name):

+        rpc_clients = sunrpc / "rpc-clients"

+        if name:

+            return [ RpcClient(rpc_clients / name) ]

+        return [ RpcClient(f) for f in sorted(rpc_clients.iterdir()) ]

+

+    def show(args):

+        for client in RpcClient.get_by_name(args.client):

+            print(client)

+

+

+parser = argparse.ArgumentParser()

+

+def show_small_help(args):

+    parser.print_usage()

+    print("sunrpc dir:", sunrpc)

+parser.set_defaults(func=show_small_help)

+

+subparser = parser.add_subparsers(title="commands")

+RpcClient.add_command(subparser)

+XprtSwitch.add_command(subparser)

+Xprt.add_command(subparser)

+

+args = parser.parse_args()

+try:

+    args.func(args)

+except Exception as e:

+    print(str(e))

+    sys.exit(1)