Date: Thu, 2 Oct 2025 09:32:51 GMT From: Dag-Erling =?utf-8?Q?Sm=C3=B8rgrav?= <des@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 5ead817c3b7a - main - rc: Teach netwait to wait for DAD Message-ID: <202510020932.5929WpJi067756@gitrepo.freebsd.org>
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The branch main has been updated by des: URL: https://cgit.FreeBSD.org/src/commit/?id=5ead817c3b7af6d6b5fea222ab144db2c3167b22 commit 5ead817c3b7af6d6b5fea222ab144db2c3167b22 Author: Dag-Erling Smørgrav <des@FreeBSD.org> AuthorDate: 2025-10-02 09:28:05 +0000 Commit: Dag-Erling Smørgrav <des@FreeBSD.org> CommitDate: 2025-10-02 09:31:16 +0000 rc: Teach netwait to wait for DAD In some configurations, especially in jails, it is possible for the system to boot so fast that we end up launching daemons while duplicate address detection is still ongoing. If that happens, said daemons may fail to bind to IPv6 addresses, as they are still tentative. Teach the netwait service to wait (up to 10 seconds, by default) for the tentative flag to vanish. MFC after: 1 week Reviewed by: olce Differential Revision: https://reviews.freebsd.org/D51889 --- libexec/rc/rc.conf | 2 ++ libexec/rc/rc.d/netwait | 84 ++++++++++++++++++++++++++++++++++-------------- share/man/man5/rc.conf.5 | 24 +++++++++----- 3 files changed, 78 insertions(+), 32 deletions(-) diff --git a/libexec/rc/rc.conf b/libexec/rc/rc.conf index c354aec44430..2589e2614c35 100644 --- a/libexec/rc/rc.conf +++ b/libexec/rc/rc.conf @@ -500,6 +500,8 @@ netwait_enable="NO" # Enable rc.d/netwait (or NO) netwait_timeout="60" # Total number of seconds to perform pings. #netwait_if="" # Wait for active link on each intf in this list. netwait_if_timeout="30" # Total number of seconds to monitor link state. +netwait_dad="NO" # Wait for DAD to complete +netwait_dad_timeout="10" # Total number of seconds to wait for DAD. ### Miscellaneous network options: ### icmp_bmcastecho="NO" # respond to broadcast ping packets diff --git a/libexec/rc/rc.d/netwait b/libexec/rc/rc.d/netwait index 3f374806d97c..b609440a2e4e 100755 --- a/libexec/rc/rc.d/netwait +++ b/libexec/rc/rc.d/netwait @@ -2,12 +2,14 @@ # # PROVIDE: netwait # REQUIRE: devd ipfw pf routing -# KEYWORD: nojail # -# The netwait script helps handle two situations: +# The netwait script helps handle three situations: # - Systems with USB or other late-attaching network hardware which # is initialized by devd events. The script waits for all the # interfaces named in the netwait_if list to appear. +# - Systems with IPv6 addresses, especially jails, where we need to +# wait for DAD to complete before starting daemons, as they will +# otherwise fail to bind to IN6ADDR_ANY. # - Systems with statically-configured IP addresses in rc.conf(5). # The IP addresses in the netwait_ip list are pinged. The script # waits for any single IP in the list to respond to the ping. If your @@ -29,28 +31,36 @@ netwait_start() { local ip rc count output link wait_if got_if any_error - if [ -z "${netwait_if}" ] && [ -z "${netwait_ip}" ]; then - err 1 "No interface or IP addresses listed, nothing to wait for" + if [ -z "${netwait_if}" ] && [ -z "${netwait_ip}" ] && + ! checkyesno netwait_dad ; then + err 1 "Nothing to wait for" fi - if [ ${netwait_timeout} -lt 1 ]; then + if ! [ "${netwait_if_timeout}" -ge 1 ]; then + err 1 "netwait_if_timeout must be >= 1" + fi + if ! [ "${netwait_dad_timeout}" -ge 1 ]; then + err 1 "netwait_dad_timeout must be >= 1" + fi + if ! [ "${netwait_timeout}" -ge 1 ]; then err 1 "netwait_timeout must be >= 1" fi + any_error=false + if [ -n "${netwait_if}" ]; then - any_error=0 for wait_if in ${netwait_if}; do echo -n "Waiting for ${wait_if}" link="" - got_if=0 + got_if=false count=1 - # Handle SIGINT (Ctrl-C); force abort of while() loop + # Handle SIGINT (Ctrl-C); force abort of while loop trap break SIGINT while [ ${count} -le ${netwait_if_timeout} ]; do if output=`/sbin/ifconfig ${wait_if} 2>/dev/null`; then - if [ ${got_if} -eq 0 ]; then + if ! ${got_if}; then echo -n ", interface present" - got_if=1 + got_if=true fi link=`expr "${output}" : '.*[[:blank:]]status: \(no carrier\)'` if [ -z "${link}" ]; then @@ -63,22 +73,45 @@ netwait_start() done # Restore default SIGINT handler trap - SIGINT - if [ ${got_if} -eq 0 ]; then + if ! ${got_if}; then echo ", wait failed: interface never appeared." - any_error=1 + any_error=true elif [ -n "${link}" ]; then echo ", wait failed: interface still has no link." - any_error=1 + any_error=true fi done - if [ ${any_error} -eq 1 ]; then - warn "Continuing with startup, but be aware you may not have " - warn "a fully functional networking layer at this point." - fi fi + if checkyesno netwait_dad; then + got_dad=false + # Handle SIGINT (Ctrl-C); force abort of while loop + trap break SIGINT + + echo -n "Waiting for DAD to complete" + count=1 + while [ ${count} -le ${netwait_dad_timeout} ]; do + if ! ifconfig | grep -q 'inet6.*tentative'; then + echo ', done.' + got_dad=true + break + fi + sleep 1 + count=$((count+1)) + done + + # Restore default SIGINT handler + trap - SIGINT + + if ! ${got_dad}; then + echo ', timed out.' + any_error=true + fi + fi + if [ -n "${netwait_ip}" ]; then - # Handle SIGINT (Ctrl-C); force abort of for() loop + got_ip=false + # Handle SIGINT (Ctrl-C); force abort of for loop trap break SIGINT for ip in ${netwait_ip}; do @@ -90,11 +123,9 @@ netwait_start() rc=$? if [ $rc -eq 0 ]; then - # Restore default SIGINT handler - trap - SIGINT - echo ', got response.' - return + got_ip=false + break 2 fi count=$((count+1)) done @@ -104,10 +135,15 @@ netwait_start() # Restore default SIGINT handler trap - SIGINT - warn "Exhausted IP list. Continuing with startup, but be aware you may" - warn "not have a fully functional networking layer at this point." + if ! ${got_ip}; then + any_error=true + fi fi + if ${any_error}; then + warn "Continuing with startup, but be aware you may not have " + warn "a fully functional networking layer at this point." + fi } load_rc_config $name diff --git a/share/man/man5/rc.conf.5 b/share/man/man5/rc.conf.5 index b8c72fc07083..c0048f27c740 100644 --- a/share/man/man5/rc.conf.5 +++ b/share/man/man5/rc.conf.5 @@ -22,7 +22,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd September 25, 2025 +.Dd October 2, 2025 .Dt RC.CONF 5 .Os .Sh NAME @@ -4563,20 +4563,16 @@ If set to .Dq Li YES , delays the start of network-reliant services until .Va netwait_if -is up and ICMP packets to a destination defined in +is up, duplicate address discovery (DAD) has completed, and ICMP +packets to a destination defined in .Va netwait_ip are flowing. -Link state is examined first, followed by +Link state is examined first, followed by DAD, then .Dq Li pinging an IP address to verify network usability. If no destination can be reached or timeouts are exceeded, network services are started anyway with no guarantee that the network is usable. -Use of this variable requires both -.Va netwait_ip -and -.Va netwait_if -to be set. .It Va netwait_ip .Pq Vt str Empty by default. @@ -4612,6 +4608,18 @@ interface if desired. Defines the total number of seconds to wait for link to become usable, polled at a 1-second interval. The default is 30. +.It Va netwait_dad +.Pq Vt str +Set to +.Dq Li NO +by default. +Set to +.Dq Li YES +to enable waiting for DAD to complete. +.It Va netwait_dad_timeout +.Pq Vt int +Indicates the total number of seconds to wait for DAD to complete. +The default is 10. .It Va rctl_enable .Pq Vt bool If set to
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