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xcp-networkd: dhclient cleanup #7138

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8109f32
networkd: make Dhclient.stop to stop the DHCP client managing the int…
semarie Jun 19, 2026
0d3b9a6
networkd: make Dhclient.ensure_running to discard previously assigned…
semarie Jun 19, 2026
2ea48ef
dhclient: add comments on functions
semarie Jun 19, 2026
f0cae55
dhclient: refactor set_ipv{4,6}_conf functions
semarie Jun 19, 2026
8b866cc
dhclient: remove `remove_conf_file` from public interface
semarie Jun 19, 2026
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136 changes: 55 additions & 81 deletions ocaml/networkd/bin/network_server.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -218,30 +218,10 @@ let reset_state () =
config := Network_config.read_management_conf reset_order

let set_gateway_interface _dbg name =
(* Remove dhclient conf (if any) for the old and new gateway interfaces.
* This ensures that dhclient gets restarted with an updated conf file when
* necessary. *)
( match !config.gateway_interface with
| Some old_iface when name <> old_iface ->
Dhclient.remove_conf_file name ;
Dhclient.remove_conf_file old_iface
| _ ->
()
) ;
debug "Setting gateway interface to %s" name ;
config := {!config with gateway_interface= Some name}

let set_dns_interface _dbg name =
(* Remove dhclient conf (if any) for the old and new DNS interfaces.
* This ensures that dhclient gets restarted with an updated conf file when
* necessary. *)
( match !config.dns_interface with
| Some old_iface when name <> old_iface ->
Dhclient.remove_conf_file name ;
Dhclient.remove_conf_file old_iface
| _ ->
()
) ;
debug "Setting DNS interface to %s" name ;
config := {!config with dns_interface= Some name}

Expand Down Expand Up @@ -474,6 +454,17 @@ module Interface = struct
)
()

let config_to_dhcp_options config =
let gateway =
Option.fold ~none:[]
~some:(fun n -> [`gateway n])
config.gateway_interface
in
let dns =
Option.fold ~none:[] ~some:(fun n -> [`dns n]) config.dns_interface
in
gateway @ dns

let get_ipv4_addr dbg name =
Debug.with_thread_associated dbg (fun () -> Ip.get_ipv4 name) ()

Expand All @@ -482,33 +473,27 @@ module Interface = struct
(fun () ->
debug "Configuring IPv4 address for %s: %s" name
(conf |> Rpcmarshal.marshal typ_of_ipv4 |> Jsonrpc.to_string) ;
update_config name {(get_config name) with ipv4_conf= conf} ;
let previous_config = get_config name in
let previous = previous_config.ipv4_conf in
update_config name {previous_config with ipv4_conf= conf} ;
(* deconfigure previous *)
Xapi_stdext_pervasives.Pervasiveext.ignore_exn (fun () ->
match previous with
| None4 ->
()
| DHCP4 ->
if conf <> DHCP4 then Dhclient.stop name
| Static4 _ -> (
match conf with Static4 _ -> () | _ -> Ip.flush_ip_addr name
)
) ;
(* configure conf *)
match conf with
| None4 ->
if List.mem name (Sysfs.list ()) then (
if Dhclient.is_running name then ignore (Dhclient.stop name) ;
Ip.flush_ip_addr name
)
()
| DHCP4 ->
let gateway =
Option.fold ~none:[]
~some:(fun n -> [`gateway n])
!config.gateway_interface
in
let dns =
Option.fold ~none:[]
~some:(fun n -> [`dns n])
!config.dns_interface
in
if not (Dhclient.is_running name) then (* Remove any static IPs *)
Ip.flush_ip_addr name ;
let options = gateway @ dns in
Dhclient.ensure_running name options
Dhclient.ensure_running name (config_to_dhcp_options !config)
| Static4 addrs ->
if Dhclient.is_running name then (
ignore (Dhclient.stop name) ;
Ip.flush_ip_addr name
) ;
(* the function is meant to be idempotent and we want to avoid
CA-239919 *)
let cur_addrs = Ip.get_ipv4 name in
Expand Down Expand Up @@ -569,53 +554,42 @@ module Interface = struct
else (
debug "Configuring IPv6 address for %s: %s" name
(conf |> Rpcmarshal.marshal typ_of_ipv6 |> Jsonrpc.to_string) ;
update_config name {(get_config name) with ipv6_conf= conf} ;
let previous_config = get_config name in
let previous = previous_config.ipv6_conf in
update_config name {previous_config with ipv6_conf= conf} ;
(* deconfigure previous *)
Xapi_stdext_pervasives.Pervasiveext.ignore_exn (fun () ->
match previous with
| None6 ->
()
| Linklocal6 ->
if conf <> Linklocal6 then Ip.flush_ip_addr ~ipv6:true name
| DHCP6 ->
if conf <> DHCP6 then Dhclient.stop ~ipv6:true name
| Autoconf6 ->
if conf <> Autoconf6 then Sysctl.set_ipv6_autoconf name false
| Static6 _ -> (
match conf with
| Static6 _ ->
()
| _ ->
Ip.flush_ip_addr ~ipv6:true name
)
) ;
(* configure conf *)
match conf with
| None6 ->
if List.mem name (Sysfs.list ()) then (
if Dhclient.is_running ~ipv6:true name then
ignore (Dhclient.stop ~ipv6:true name) ;
Sysctl.set_ipv6_autoconf name false ;
Ip.flush_ip_addr ~ipv6:true name
)
()
| Linklocal6 ->
if List.mem name (Sysfs.list ()) then (
if Dhclient.is_running ~ipv6:true name then
ignore (Dhclient.stop ~ipv6:true name) ;
Sysctl.set_ipv6_autoconf name false ;
Ip.flush_ip_addr ~ipv6:true name ;
Ip.set_ipv6_link_local_addr name
)
Ip.set_ipv6_link_local_addr name
| DHCP6 ->
let gateway =
Option.fold ~none:[]
~some:(fun n -> [`gateway n])
!config.gateway_interface
in
let dns =
Option.fold ~none:[]
~some:(fun n -> [`dns n])
!config.dns_interface
in
if Dhclient.is_running ~ipv6:true name then
ignore (Dhclient.stop ~ipv6:true name) ;
Sysctl.set_ipv6_autoconf name false ;
Ip.flush_ip_addr ~ipv6:true name ;
Ip.set_ipv6_link_local_addr name ;
let options = gateway @ dns in
ignore (Dhclient.ensure_running ~ipv6:true name options)
Dhclient.ensure_running ~ipv6:true name
(config_to_dhcp_options !config)
| Autoconf6 ->
if Dhclient.is_running ~ipv6:true name then
ignore (Dhclient.stop ~ipv6:true name) ;
Ip.flush_ip_addr ~ipv6:true name ;
Ip.set_ipv6_link_local_addr name ;
Sysctl.set_ipv6_autoconf name true
(* Cannot link set down/up due to CA-89882 - IPv4 default route
cleared *)
| Static6 addrs ->
if Dhclient.is_running ~ipv6:true name then
ignore (Dhclient.stop ~ipv6:true name) ;
Sysctl.set_ipv6_autoconf name false ;
(* add the link_local and clean the old one only when needed *)
let cur_addrs =
let addrs = Ip.get_ipv6 name in
Expand Down
105 changes: 68 additions & 37 deletions ocaml/networkd/lib/network_utils.ml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -913,20 +913,20 @@ end
module Dhclient : sig
type interface = string

val remove_conf_file : ?ipv6:bool -> interface -> unit

val is_running : ?ipv6:bool -> interface -> bool

val stop : ?ipv6:bool -> interface -> unit
(** stop: stop the DHCP client managing [interface] if running and to unconfigure addresses. *)

val ensure_running :
?ipv6:bool
-> interface
-> [> `dns of string | `gateway of string] list
-> unit
(** ensure_running: ensure the DHCP client is up and running. On start, any previously assigned
addresses are discarded. *)
end = struct
type interface = string

(** pid_file: path to dhclient pidfile. *)
let pid_file ?(ipv6 = false) interface =
let ipv6' =
if ipv6 then
Expand All @@ -936,6 +936,7 @@ end = struct
in
Printf.sprintf "/var/run/dhclient%s-%s.pid" ipv6' interface

(** lease_file: path to dhclient lease file. *)
let lease_file ?(ipv6 = false) interface =
let ipv6' =
if ipv6 then
Expand All @@ -946,6 +947,7 @@ end = struct
Filename.concat "/var/lib/xcp"
(Printf.sprintf "dhclient%s-%s.leases" ipv6' interface)

(** conf_file: path of the dhclient configuration file. *)
let conf_file ?(ipv6 = false) interface =
let ipv6' =
if ipv6 then
Expand All @@ -956,6 +958,7 @@ end = struct
Filename.concat "/var/lib/xcp"
(Printf.sprintf "dhclient%s-%s.conf" ipv6' interface)

(** generate_conf: return the content of dhclient configuration file. *)
let[@warning "-27"] generate_conf ?(ipv6 = false) interface options =
let send = "host-name = gethostname()" in
let minimal =
Expand Down Expand Up @@ -993,21 +996,25 @@ end = struct
interface send
(String.concat ", " request)

(** read_conf_file: returns the content of dhclient configuration file. *)
let read_conf_file ?(ipv6 = false) interface =
let file = conf_file ~ipv6 interface in
try Some (Xapi_stdext_unix.Unixext.string_of_file file) with _ -> None

(** write_conf_file: write updated dhclient configuration file to disk. *)
let write_conf_file ?(ipv6 = false) interface options =
let conf = generate_conf ~ipv6 interface options in
Xapi_stdext_unix.Unixext.write_string_to_file
(conf_file ~ipv6 interface)
conf

(** remove_conf_file: unlink the dhclient configuration file from disk. *)
let remove_conf_file ?(ipv6 = false) interface =
let file = conf_file ~ipv6 interface in
try Unix.unlink file with _ -> ()

let start ?(ipv6 = false) interface options =
(** dhclient_start: configure and start dhclient. *)
let dhclient_start ~ipv6 interface options =
(* If we have a gateway interface, pass it to dhclient-script via -e *)
(* This prevents the default route being set erroneously on CentOS *)
(* Normally this wouldn't happen as we're not requesting routers, *)
Expand All @@ -1027,63 +1034,87 @@ end = struct
else
["-e"; "PEERDNS=no"]
in
write_conf_file ~ipv6 interface options ;
let ipv6' =
if ipv6 then
["-6"]
else
[]
in
call_script ~timeout:None dhclient
(ipv6'
@ gw_opt
@ dns_opt
@ [
"-q"
; "-pf"
; pid_file ~ipv6 interface
; "-lf"
; lease_file ~ipv6 interface
; "-cf"
; conf_file ~ipv6 interface
; interface
]
)

let stop ?(ipv6 = false) interface =
try
ignore
(call_script dhclient
[
"-r"
(* create an up-to-date configuration file. *)
write_conf_file ~ipv6 interface options ;
(* start dhclient *)
ignore
(call_script ~timeout:None dhclient
(ipv6'
@ gw_opt
@ dns_opt
@ [
"-q"
; "-pf"
; pid_file ~ipv6 interface
; "-lf"
; lease_file ~ipv6 interface
; "-cf"
; conf_file ~ipv6 interface
; interface
]
) ;
Unix.unlink (pid_file ~ipv6 interface)
with _ -> ()
)
)

(* dhclient_stop: stop the running dhclient. release lease if asked. *)
let dhclient_stop ~ipv6 ~release interface =
remove_conf_file ~ipv6 interface ;
ignore
(call_script dhclient
[
( if release then
"-r"
else
"-x"
)
; "-pf"
; pid_file ~ipv6 interface
; "-lf"
; lease_file ~ipv6 interface
; interface
]
)

let is_running ?(ipv6 = false) interface =
let start ?(ipv6 = false) interface options =
(* remove previously assigned addresses (like static ones) *)
Ip.flush_ip_addr interface ;
(* start DHCP client *)
dhclient_start ~ipv6 interface options

(* is_running: returns if the DHCP client is running. *)
let is_running ~ipv6 interface =
try
Unix.access (pid_file ~ipv6 interface) [Unix.F_OK] ;
true
with Unix.Unix_error _ -> false

let stop ?(ipv6 = false) interface =
if is_running ~ipv6 interface then
try
(* release DHCP lease and close the DHCP client *)
dhclient_stop ~ipv6 ~release:true interface ;
(* flush configured addresses *)
Ip.flush_ip_addr ~ipv6 interface ;
(* remove the pid file *)
Unix.unlink (pid_file ~ipv6 interface)
with _ -> ()

let ensure_running ?(ipv6 = false) interface options =
if not (is_running ~ipv6 interface) then
(* dhclient is not running, so we need to start it. *)
ignore (start ~ipv6 interface options)
start ~ipv6 interface options
else
(* dhclient is running - if the config has changed, update the config file
and restart. *)
(* dhclient is running, if the config has changed, reload it. *)
let current_conf = read_conf_file ~ipv6 interface in
let new_conf = generate_conf ~ipv6 interface options in
if current_conf <> Some new_conf then (
ignore (stop ~ipv6 interface) ;
ignore (start ~ipv6 interface options)
dhclient_stop ~ipv6 ~release:false interface ;
dhclient_start ~ipv6 interface options
)
end

Expand Down
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