From eacd1dacfa17c4cfa62f804d3744554cb477e25a Mon Sep 17 00:00:00 2001
From: Beniamino Galvani <bgalvani@redhat.com>
Date: Mon, 1 Feb 2021 16:32:01 +0100
Subject: [PATCH 1/2] device: preserve the DHCPv6 mode when renewing the lease

(cherry picked from commit 14600548158f8159847ba06a3f2f5eef2bb52881)
---
 src/devices/nm-device.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 4144c2a1b9..de93f2233c 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -9862,13 +9862,16 @@ gboolean
 nm_device_dhcp6_renew(NMDevice *self, gboolean release)
 {
     NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE(self);
+    NMNDiscDHCPLevel mode;
 
     g_return_val_if_fail(priv->dhcp_data_6.client != NULL, FALSE);
 
     _LOGI(LOGD_DHCP6, "DHCPv6 lease renewal requested");
 
     /* Terminate old DHCP instance and release the old lease */
+    mode = priv->dhcp6.mode;
     dhcp6_cleanup(self, CLEANUP_TYPE_DECONFIGURE, release);
+    priv->dhcp6.mode = mode;
 
     /* Start DHCP again on the interface */
     return dhcp6_start(self, FALSE);

From cf6c9253f6cabc1be802a83b2809c39df8c6fcb6 Mon Sep 17 00:00:00 2001
From: Beniamino Galvani <bgalvani@redhat.com>
Date: Mon, 1 Feb 2021 18:02:37 +0100
Subject: [PATCH 2/2] dhcp: fix requesting prefixes in stateless mode

According to RFC3315 section 15.12, Information-request messages can't
include a IA option (such as IA_NA or IA_PD).

When doing stateless DHCPv6, we start the client in the appropriate
mode to issue an Information-request message: with "-S" for dhclient or
calling sd_dhcp6_client_set_information_request(TRUE) for systemd.

However, if we need a prefix later, the client must be restarted to
ask the prefix. Currently both dhclient and systemd clients are still
configured to send an Information-request with prefixes. Fix that.

(cherry picked from commit 6ed95bd8e53f5ae274b726bc3fcd78b00058621f)
---
 src/dhcp/nm-dhcp-dhclient.c | 6 ++++++
 src/dhcp/nm-dhcp-systemd.c  | 7 +++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/dhcp/nm-dhcp-dhclient.c b/src/dhcp/nm-dhcp-dhclient.c
index 260f400e3e..5dc1e9ec67 100644
--- a/src/dhcp/nm-dhcp-dhclient.c
+++ b/src/dhcp/nm-dhcp-dhclient.c
@@ -437,6 +437,12 @@ dhclient_start(NMDhcpClient *client,
 
     if (addr_family == AF_INET6) {
         g_ptr_array_add(argv, (gpointer) "-6");
+
+        if (prefixes > 0 && nm_streq0(mode_opt, "-S")) {
+            /* -S is incompatible with -P, only use the latter */
+            mode_opt = NULL;
+        }
+
         if (mode_opt)
             g_ptr_array_add(argv, (gpointer) mode_opt);
         while (prefixes--)
diff --git a/src/dhcp/nm-dhcp-systemd.c b/src/dhcp/nm-dhcp-systemd.c
index f929722377..09d11713ee 100644
--- a/src/dhcp/nm-dhcp-systemd.c
+++ b/src/dhcp/nm-dhcp-systemd.c
@@ -969,8 +969,11 @@ ip6_start(NMDhcpClient *            client,
 
     _LOGT("dhcp-client6: set %p", sd_client);
 
-    if (nm_dhcp_client_get_info_only(client))
-        sd_dhcp6_client_set_information_request(sd_client, 1);
+    if (nm_dhcp_client_get_info_only(client)) {
+        sd_dhcp6_client_set_address_request(sd_client, 0);
+        if (needed_prefixes == 0)
+            sd_dhcp6_client_set_information_request(sd_client, 1);
+    }
 
     r = sd_dhcp6_client_set_iaid(sd_client, nm_dhcp_client_get_iaid(client));
     if (r < 0) {