From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Thu, 19 Oct 2023 15:16:39 +0000 (+0900)
Subject: sd-dhcp-client: add a short comment about IPv6 only mode
X-Git-Tag: v255-rc1~161^2~2
X-Git-Url: http://git-history.diyao.me/?a=commitdiff_plain;h=74c102d7e9e04695476ca7fe1cec088a938ffb11;p=systemd%2F.git

sd-dhcp-client: add a short comment about IPv6 only mode
---

diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 7e36908937..d27609655f 100644
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -1906,6 +1906,13 @@ static int client_enter_bound(sd_dhcp_client *client, int notify_event) {
         client->start_delay = 0;
         (void) event_source_disable(client->timeout_resend);
 
+        /* RFC 8925 section 3.2
+         * If the client is in the INIT-REBOOT state, it SHOULD stop the DHCPv4 configuration process or
+         * disable the IPv4 stack completely for V6ONLY_WAIT seconds or until the network attachment event,
+         * whichever happens first.
+         *
+         * In the below, the condition uses REBOOTING, instead of INIT-REBOOT, as the client state has
+         * already transitioned from INIT-REBOOT to REBOOTING after sending a DHCPREQUEST message. */
         if (client->state == DHCP_STATE_REBOOTING && client->lease->ipv6_only_preferred_usec > 0) {
                 if (client->ipv6_acquired) {
                         log_dhcp_client(client,