dhcp: include "dhcp6_ntp_server" in Dhcp6Config

Works for the internal DHCP client only as sd-dhcp does the option
parsing for us.

The option 56 is not understood by dhclient so we would need to parse it
ourselves. Let's not do it for now, as the RFC seems to written in a
somewhat poor taste.

https://bugzilla.redhat.com/show_bug.cgi?id=2047415#c2

3 files changed, 30 insertions, 1 deletions

diff --git a/src/core/dhcp/nm-dhcp-options.c b/src/core/dhcp/nm-dhcp-options.c
index 38806a4223..5c358935a3 100644
--- a/src/core/dhcp/nm-dhcp-options.c
+++ b/src/core/dhcp/nm-dhcp-options.c
@@ -201,6 +201,7 @@ const NMDhcpOption _nm_dhcp_option_dhcp6_options[] = {
     REQ(NM_DHCP_OPTION_DHCP6_DOMAIN_LIST, "dhcp6_domain_search", TRUE),
     REQ(NM_DHCP_OPTION_DHCP6_SNTP_SERVERS, "dhcp6_sntp_servers", TRUE),
     REQ(NM_DHCP_OPTION_DHCP6_FQDN, "fqdn_fqdn", FALSE),
+    REQ(NM_DHCP_OPTION_DHCP6_NTP_SERVER, "dhcp6_ntp_server", TRUE),
     REQ(NM_DHCP_OPTION_DHCP6_MUD_URL, "dhcp6_mud_url", FALSE),
 
     /* Internal values */
@@ -235,6 +236,7 @@ static const NMDhcpOption *const _sorted_options_6[G_N_ELEMENTS(_nm_dhcp_option_
     A(13),
     A(14),
     A(15),
+    A(16),
 #undef A
 };
 
diff --git a/src/core/dhcp/nm-dhcp-options.h b/src/core/dhcp/nm-dhcp-options.h
index 1e26a5bfe3..4c978c4f97 100644
--- a/src/core/dhcp/nm-dhcp-options.h
+++ b/src/core/dhcp/nm-dhcp-options.h
@@ -163,6 +163,7 @@ typedef enum {
     NM_DHCP_OPTION_DHCP6_DOMAIN_LIST  = 24,
     NM_DHCP_OPTION_DHCP6_SNTP_SERVERS = 31,
     NM_DHCP_OPTION_DHCP6_FQDN         = 39,
+    NM_DHCP_OPTION_DHCP6_NTP_SERVER   = 56, /* RFC 5908 */
     NM_DHCP_OPTION_DHCP6_MUD_URL      = 112,
 
     /* Internal values */
@@ -187,7 +188,7 @@ typedef struct {
 } NMDhcpOption;
 
 extern const NMDhcpOption _nm_dhcp_option_dhcp4_options[143];
-extern const NMDhcpOption _nm_dhcp_option_dhcp6_options[16];
+extern const NMDhcpOption _nm_dhcp_option_dhcp6_options[17];
 
 static inline const char *
 nm_dhcp_option_get_name(const NMDhcpOption *option)
diff --git a/src/core/dhcp/nm-dhcp-systemd.c b/src/core/dhcp/nm-dhcp-systemd.c
index 46da3b7630..0884def35d 100644
--- a/src/core/dhcp/nm-dhcp-systemd.c
+++ b/src/core/dhcp/nm-dhcp-systemd.c
@@ -771,6 +771,8 @@ lease_to_ip6_config(NMDedupMultiIndex *multi_idx,
     uint32_t                                lft_pref, lft_valid;
     char                                    addr_str[NM_UTILS_INET_ADDRSTRLEN];
     char                                  **domains;
+    char                                  **ntp_fqdns;
+    const struct in6_addr                  *ntp_addrs;
     const char                             *s;
     nm_auto_free_gstring GString           *str               = NULL;
     gboolean                                has_any_addresses = FALSE;
@@ -839,6 +841,30 @@ lease_to_ip6_config(NMDedupMultiIndex *multi_idx,
         nm_dhcp_option_add_option(options, AF_INET6, NM_DHCP_OPTION_DHCP6_FQDN, s);
     }
 
+    /* RFC 5908, section 4 states: "This option MUST include one, and only
+     * one, time source suboption." It is not clear why systemd chose to
+     * return array of addresses and FQDNs. Given there seem to be no
+     * technical obstacles to including multiple options, let's just
+     * pass on whatever systemd tells us.
+     */
+    nm_gstring_prepare(&str);
+    num = sd_dhcp6_lease_get_ntp_fqdn(lease, &ntp_fqdns);
+    if (num > 0) {
+        for (i = 0; i < num; i++) {
+            g_string_append(nm_gstring_add_space_delimiter(str), ntp_fqdns[i]);
+        }
+    }
+    num = sd_dhcp6_lease_get_ntp_addrs(lease, &ntp_addrs);
+    if (num > 0) {
+        for (i = 0; i < num; i++) {
+            _nm_utils_inet6_ntop(&ntp_addrs[i], addr_str);
+            g_string_append(nm_gstring_add_space_delimiter(str), addr_str);
+        }
+    }
+    if (str->len) {
+        nm_dhcp_option_add_option(options, AF_INET6, NM_DHCP_OPTION_DHCP6_NTP_SERVER, str->str);
+    }
+
     nm_l3_config_data_set_dhcp_lease_from_options(l3cd, AF_INET6, g_steal_pointer(&options));
 
     return g_steal_pointer(&l3cd);