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netd: watch conf.d with inotify, retry on backend failure

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Two races could prevent DHCP-learned default routes from being installed
at boot:

1. The signal from the DHCP client script could be lost leaving conf.d
   updated but frr.conf stale.

2. Even when the signal was received, 'vtysh -b' could fail because the
   FRR daemon chain (mgmtd→zebra→staticd) writes PID files before being
   fully operational, causing netd to give up with no retry.

Fix both by refactoring netd to use libev:

- Use an inotify watch of CONF_DIR, so netd reacts directly to file
  changes without depending on signal delivery.

- On backend_apply() failure, schedule a retry in 5s and call pidfile()
  unconditionally so dependent services are not blocked waiting for the
  Finit condition 'pid/netd' to be satisfied.

We also take this opportunity to rename /etc/netd/conf.d/ to /etc/net.d/
The extra /etc/netd/ directory level served no purpose — nothing else
lives there.  Flatten to /etc/net.d/ which reads more naturally as the
drop-in directory for network configuration snippets.

Also, reduce logging a bit since each netd backend already logs success
or fail which is sufficient to know that a configuration change has been
applied or not.

Finally, with the new inotify processing in netd it's redundant to call
'initctl reload netd' from the udhcpc script, in fact it will only cause
unnecessary overhead, so we drop it.

Fixes #1438

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
This commit is contained in:
Joachim Wiberg
2026-03-12 12:07:49 +01:00
parent cb243304ad
commit 221fea13a2
10 changed files with 109 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files
board/common/rootfs/etc/netd/conf.d/.empty
View File
board/common/rootfs/usr/share/udhcpc/default.script
+1 -5
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@@ -7,7 +7,7 @@ ACTION="$1"
IP_CACHE="/var/lib/misc/${interface}.cache"
RESOLV_CONF="/run/resolvconf/interfaces/${interface}.conf"
NTPFILE="/run/chrony/dhcp-sources.d/${interface}.sources"
NAME="/etc/netd/conf.d/${interface}-dhcp.conf"
NAME="/etc/net.d/${interface}-dhcp.conf"
NEXT="${NAME}+"
[ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"
@@ -118,8 +118,6 @@ set_dhcp_routes()
# Reduce changes needed by comparing with previous route(s)
cmp -s "$NAME" "$NEXT" && return
mv "$NEXT" "$NAME"
initctl reload netd
}
clr_dhcp_routes()
@@ -127,8 +125,6 @@ clr_dhcp_routes()
log "deleting DHCP routes"
[ -f "$NAME" ] || return
rm "$NAME"
initctl reload netd
}
clr_dhcp_addresses()
package/netd/Config.in
+2 -1
View File
@@ -2,9 +2,10 @@ config BR2_PACKAGE_NETD
bool "netd"
select BR2_PACKAGE_LIBITE
select BR2_PACKAGE_LIBCONFUSE
select BR2_PACKAGE_LIBEV
help
Network route daemon. Manages static routes and RIP routing.
Reads configuration from /etc/netd/conf.d/*.conf.
Reads configuration from /etc/net.d/*.conf.
With FRR: Full routing via gRPC, vtysh, or frr.conf.
Without FRR: Standalone Linux backend via rtnetlink.
package/netd/netd.mk
+2 -2
View File
@@ -4,13 +4,13 @@
#
################################################################################
NETD_VERSION = 1.0
NETD_VERSION = 1.1.0
NETD_SITE_METHOD = local
NETD_SITE = $(BR2_EXTERNAL_INFIX_PATH)/src/netd
NETD_LICENSE = BSD-3-Clause
NETD_LICENSE_FILES = LICENSE
NETD_REDISTRIBUTE = NO
NETD_DEPENDENCIES = libite libconfuse jansson
NETD_DEPENDENCIES = libite libconfuse jansson libev
NETD_AUTORECONF = YES
NETD_CONF_ENV = CFLAGS="$(INFIX_CFLAGS)"
src/confd/src/routing.c
+1 -1
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@@ -8,7 +8,7 @@
#define XPATH_BASE_ "/ietf-routing:routing/control-plane-protocols/control-plane-protocol"
#define XPATH_OSPF_ XPATH_BASE_ "/ietf-ospf:ospf"
#define NETD_CONF "/etc/netd/conf.d/confd.conf"
#define NETD_CONF "/etc/net.d/confd.conf"
#define NETD_CONF_NEXT NETD_CONF "+"
#define NETD_CONF_PREV NETD_CONF "-"
#define OSPFD_CONF "/etc/frr/ospfd.conf"
src/netd/Makefile.am
+1 -1
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@@ -6,7 +6,7 @@ netd_SOURCES = src/netd.c src/netd.h src/config.c src/config.h
netd_CPPFLAGS = -D_DEFAULT_SOURCE -D_GNU_SOURCE -I$(srcdir)/src
netd_CFLAGS = -W -Wall -Wextra
netd_CFLAGS += $(libite_CFLAGS) $(libconfuse_CFLAGS) $(jansson_CFLAGS)
netd_LDADD = $(libite_LIBS) $(libconfuse_LIBS) $(jansson_LIBS)
netd_LDADD = $(libite_LIBS) $(libconfuse_LIBS) $(jansson_LIBS) $(EV_LIBS)
# Backend selection: FRR gRPC, FRR frr.conf, or Linux kernel
if HAVE_FRR_GRPC
src/netd/README.md
+4 -4
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@@ -60,7 +60,7 @@ make install
netd uses [libconfuse](https://github.com/martinh/libconfuse) for configuration parsing, providing a clean and structured format.
Configuration files are placed in `/etc/netd/conf.d/` with the `.conf` extension. Files are processed in alphabetical order.
Configuration files are placed in `/etc/net.d/` with the `.conf` extension. Files are processed in alphabetical order.
### Configuration Format
@@ -219,10 +219,10 @@ rip {
### Configuration Files
Configuration files must be placed in `/etc/netd/conf.d/` with the `.conf` extension:
Configuration files must be placed in `/etc/net.d/` with the `.conf` extension:
```bash
/etc/netd/conf.d/
/etc/net.d/
├── 10-static.conf # Static routes
├── 20-rip.conf # RIP configuration
└── 99-local.conf # Local overrides
@@ -256,7 +256,7 @@ netd validates configuration on reload. Check syslog for errors.
```
┌─────────┐
│ confd │ Writes /etc/netd/conf.d/confd.conf
│ confd │ Writes /etc/net.d/confd.conf
└────┬────┘
│ SIGHUP
▼
src/netd/configure.ac
+11 -1
View File
@@ -1,5 +1,5 @@
AC_PREREQ(2.61)
AC_INIT([netd], [1.0.0], [https://github.com/kernelkit/infix/issues])
AC_INIT([netd], [1.1.0], [https://github.com/kernelkit/infix/issues])
AM_INIT_AUTOMAKE(1.11 foreign subdir-objects)
AM_SILENT_RULES(yes)
@@ -81,6 +81,16 @@ PKG_CHECK_MODULES([libite], [libite >= 2.6.1])
PKG_CHECK_MODULES([libconfuse], [libconfuse >= 3.0])
PKG_CHECK_MODULES([jansson], [jansson >= 2.0])
AC_CHECK_HEADER([ev.h],
[saved_LIBS="$LIBS"
AC_CHECK_LIB([ev], [ev_loop_new],
[EV_LIBS="-lev"],
[AC_MSG_ERROR("libev not found")])
LIBS="$saved_LIBS"],
[AC_MSG_ERROR("ev.h not found")]
)
AC_SUBST([EV_LIBS])
test "x$prefix" = xNONE && prefix=$ac_default_prefix
test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
src/netd/src/netd.c
+86 -41
View File
@@ -2,6 +2,8 @@
#include <errno.h>
#include <getopt.h>
#include <sys/inotify.h>
#include <ev.h>
#include <libite/lite.h>
#include "netd.h"
@@ -9,9 +11,6 @@
int debug;
static sig_atomic_t do_reload;
static sig_atomic_t do_shutdown;
static struct route_head active_routes = TAILQ_HEAD_INITIALIZER(active_routes);
static struct rip_config active_rip;
@@ -46,19 +45,7 @@ static int backend_apply(struct route_head *routes, struct rip_config *rip) {
}
#endif
static void sighup_handler(int sig)
{
(void)sig;
INFO("Got SIGHUP, reloading ...");
do_reload = 1;
}
static void sigterm_handler(int sig)
{
(void)sig;
do_shutdown = 1;
}
static ev_timer retry_w;
static void route_list_free(struct route_head *head)
{
@@ -118,7 +105,7 @@ static void rip_config_free(struct rip_config *cfg)
}
}
static void reload(void)
static void reload(struct ev_loop *loop)
{
struct route_head new_routes = TAILQ_HEAD_INITIALIZER(new_routes);
struct rip_redistribute *redist;
@@ -129,7 +116,7 @@ static void reload(void)
struct route *r;
int count = 0;
INFO("Reloading configuration");
DEBUG("Reloading configuration");
rip_config_init(&new_rip);
@@ -148,11 +135,16 @@ static void reload(void)
/* Apply config via backend */
if (backend_apply(&new_routes, &new_rip)) {
ERROR("Failed applying config via backend");
ERROR("Failed applying config via backend, retry in 5s");
route_list_free(&new_routes);
rip_config_free(&new_rip);
ev_timer_stop(loop, &retry_w);
ev_timer_set(&retry_w, 5., 0.);
ev_timer_start(loop, &retry_w);
pidfile(NULL);
return;
}
ev_timer_stop(loop, &retry_w);
route_list_free(&active_routes);
TAILQ_INIT(&active_routes);
@@ -214,26 +206,59 @@ static void reload(void)
}
}
INFO("Configuration reloaded");
pidfile(NULL);
}
static void inotify_cb(struct ev_loop *loop, ev_io *w, int revents)
{
char buf[sizeof(struct inotify_event) + NAME_MAX + 1];
(void)revents;
while (read(w->fd, buf, sizeof(buf)) > 0)
;
DEBUG("conf.d changed, triggering reload");
reload(loop);
}
static void sighup_cb(struct ev_loop *loop, ev_signal *w, int revents)
{
(void)w; (void)revents;
INFO("Got SIGHUP, reloading ...");
reload(loop);
}
static void sigterm_cb(struct ev_loop *loop, ev_signal *w, int revents)
{
(void)w; (void)revents;
ev_break(loop, EVBREAK_ALL);
}
static void retry_cb(struct ev_loop *loop, ev_timer *w, int revents)
{
(void)w; (void)revents;
reload(loop);
}
static int usage(int rc)
{
fprintf(stderr,
"Usage: netd [-dh]\n"
"Usage: netd [-dhv]\n"
" -d Enable debug (log to stderr)\n"
" -h Show this help text\n");
" -h Show this help text\n"
" -v Show version and exit\n");
return rc;
}
int main(int argc, char *argv[])
{
struct ev_loop *loop = EV_DEFAULT;
ev_signal sighup_w, sigterm_w, sigint_w;
ev_io inotify_w;
int log_opts = LOG_PID | LOG_NDELAY;
struct sigaction sa = { 0 };
int ifd = -1;
int c;
while ((c = getopt(argc, argv, "dhp:")) != -1) {
while ((c = getopt(argc, argv, "dhv")) != -1) {
switch (c) {
case 'd':
log_opts |= LOG_PERROR;
@@ -241,6 +266,9 @@ int main(int argc, char *argv[])
break;
case 'h':
return usage(0);
case 'v':
puts("v" PACKAGE_VERSION);
return 0;
default:
return usage(1);
}
@@ -248,15 +276,7 @@ int main(int argc, char *argv[])
openlog("netd", log_opts, LOG_DAEMON);
setlogmask(LOG_UPTO(LOG_INFO));
INFO("starting");
/* Set up signal handlers */
sa.sa_handler = sighup_handler;
sigaction(SIGHUP, &sa, NULL);
sa.sa_handler = sigterm_handler;
sigaction(SIGTERM, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
INFO("v%s starting", PACKAGE_VERSION);
if (backend_init()) {
ERROR("Failed to initialize backend");
@@ -267,19 +287,44 @@ int main(int argc, char *argv[])
TAILQ_INIT(&active_routes);
rip_config_init(&active_rip);
/* Initial load */
do_reload = 1;
/* Signal watchers */
ev_signal_init(&sighup_w, sighup_cb, SIGHUP);
ev_signal_start(loop, &sighup_w);
while (!do_shutdown) {
if (do_reload) {
do_reload = 0;
reload();
}
pause();
ev_signal_init(&sigterm_w, sigterm_cb, SIGTERM);
ev_signal_start(loop, &sigterm_w);
ev_signal_init(&sigint_w, sigterm_cb, SIGINT);
ev_signal_start(loop, &sigint_w);
/* Retry timer — one-shot, started only on backend failure */
ev_timer_init(&retry_w, retry_cb, 0., 0.);
/* Watch conf.d for changes so we don't rely solely on signals */
mkdir(CONF_DIR, 0755);
ifd = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
if (ifd < 0) {
ERROR("inotify_init1: %s, falling back to signals only", strerror(errno));
} else if (inotify_add_watch(ifd, CONF_DIR,
IN_CLOSE_WRITE | IN_DELETE |
IN_MOVED_TO | IN_MOVED_FROM) < 0) {
ERROR("inotify_add_watch %s: %s", CONF_DIR, strerror(errno));
close(ifd);
ifd = -1;
} else {
ev_io_init(&inotify_w, inotify_cb, ifd, EV_READ);
ev_io_start(loop, &inotify_w);
}
/* Initial load */
reload(loop);
ev_run(loop, 0);
INFO("shutting down");
if (ifd >= 0)
close(ifd);
route_list_free(&active_routes);
rip_config_free(&active_rip);
backend_cleanup();
src/netd/src/netd.h
+1 -1
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@@ -21,7 +21,7 @@ extern int debug;
#define INFO(fmt, args...) LOG(LOG_INFO, fmt, ##args)
#define DEBUG(fmt, args...) do { if (debug) LOG(LOG_DEBUG, fmt, ##args); } while (0)
#define CONF_DIR "/etc/netd/conf.d"
#define CONF_DIR "/etc/net.d"
/* Nexthop types */
enum nh_type {