dhclient: save DUID to dhclient leasefiles when required

The DUID is supposed to be machine-wide, so if we're writing a new
leasefile, save the default DUID to it.  If we haven't saved a
persistent DUID yet, do that to.

src/dhcp-manager/nm-dhcp-dhclient-utils.c

@@ -364,3 +364,57 @@ nm_dhcp_dhclient_read_duid (const char *leasefile, GError **error)
 	return duid;
 }
 
+gboolean
+nm_dhcp_dhclient_save_duid (const char *leasefile,
+                            const char *escaped_duid,
+                            GError **error)
+{
+	char **lines = NULL, **iter, *l;
+	GString *s;
+	gboolean success;
+	gsize len = 0;
+
+	g_return_val_if_fail (leasefile != NULL, FALSE);
+	g_return_val_if_fail (escaped_duid != NULL, FALSE);
+
+	if (g_file_test (leasefile, G_FILE_TEST_EXISTS)) {
+		char *contents = NULL;
+
+		if (!g_file_get_contents (leasefile, &contents, &len, error)) {
+			g_prefix_error (error, "failed to read lease file %s: ", leasefile);
+			return FALSE;
+		}
+
+		/* If the file already contains an uncommented DUID, leave it */
+		g_assert (contents);
+		lines = g_strsplit_set (contents, "\n\r", -1);
+		g_free (contents);
+		for (iter = lines; iter && *iter; iter++) {
+			l = *iter;
+			while (g_ascii_isspace (*l))
+				l++;
+			if (g_str_has_prefix (l, DUID_PREFIX)) {
+				g_strfreev (lines);
+				return TRUE;
+			}
+		}
+	}
+
+	s = g_string_sized_new (len + 50);
+	g_string_append_printf (s, DUID_PREFIX "%s\";\n", escaped_duid);
+
+	/* Preserve existing leasefile contents */
+	if (lines) {
+		for (iter = lines; iter && *iter; iter++)
+			g_string_append (s, *iter[0] ? *iter : "\n");
+		g_strfreev (lines);
+	}
+
+	success = g_file_set_contents (leasefile, s->str, -1, error);
+	if (!success)
+		g_prefix_error (error, "failed to set DUID in lease file %s: ", leasefile);
+
+	g_string_free (s, TRUE);
+	return success;
+}
+

src/dhcp-manager/nm-dhcp-dhclient-utils.h

@@ -40,5 +40,9 @@ GByteArray *nm_dhcp_dhclient_unescape_duid (const char *duid);
 
 GByteArray *nm_dhcp_dhclient_read_duid (const char *leasefile, GError **error);
 
+gboolean nm_dhcp_dhclient_save_duid (const char *leasefile,
+                                     const char *escaped_duid,
+                                     GError **error);
+
 #endif /* NM_DHCP_DHCLIENT_UTILS_H */
 

src/dhcp-manager/nm-dhcp-dhclient.c

@@ -53,6 +53,8 @@ typedef struct {
 	const char *def_leasefile;
 	char *lease_file;
 	char *pid_file;
+	gboolean lease_duid_found;
+	gboolean default_duid_found;
 } NMDHCPDhclientPrivate;
 
 const char *
@@ -446,6 +448,7 @@ dhclient_child_setup (gpointer user_data G_GNUC_UNUSED)
 static GPid
 dhclient_start (NMDHCPClient *client,
                 const char *mode_opt,
+                const GByteArray *duid,
                 gboolean release)
 {
 	NMDHCPDhclientPrivate *priv = NM_DHCP_DHCLIENT_GET_PRIVATE (client);
@@ -496,6 +499,36 @@ dhclient_start (NMDHCPClient *client,
 		return -1;
 	}
 
+	if (ipv6 && duid) {
+		char *escaped = NULL;
+
+		escaped = nm_dhcp_dhclient_escape_duid (duid);
+
+		/* Save the generated DUID into the default leasefile for persistent storage */
+		if (!priv->default_duid_found) {
+			nm_log_dbg (LOGD_DHCP6, "Saving DHCPv6 DUID '%s' to leasefile %s",
+			            escaped, priv->def_leasefile);
+			if (!nm_dhcp_dhclient_save_duid (priv->def_leasefile, escaped, &error)) {
+				g_assert (error);
+				nm_log_warn (LOGD_DHCP6, "Could not save DUID: %s", error->message);
+				g_clear_error (&error);
+			}
+		}
+
+		/* Save the DUID to the network-specific leasefile so it'll actually get used */
+		if (!priv->lease_duid_found) {
+			nm_log_dbg (LOGD_DHCP6, "Saving DHCPv6 DUID '%s' to leasefile %s",
+			            escaped, priv->lease_file);
+			if (!nm_dhcp_dhclient_save_duid (priv->lease_file, escaped, &error)) {
+				g_assert (error);
+				nm_log_warn (LOGD_DHCP6, "Could not save DUID: %s", error->message);
+				g_clear_error (&error);
+			}
+		}
+
+		g_free (escaped);
+	}
+
 	argv = g_ptr_array_new ();
 	g_ptr_array_add (argv, (gpointer) priv->path);
 
@@ -576,7 +609,7 @@ ip4_start (NMDHCPClient *client,
 		return -1;
 	}
 
-	return dhclient_start (client, NULL, FALSE);
+	return dhclient_start (client, NULL, NULL, FALSE);
 }
 
 static GPid
@@ -598,7 +631,7 @@ ip6_start (NMDHCPClient *client,
 		return -1;
 	}
 
-	return dhclient_start (client, info_only ? "-S" : "-N", FALSE);
+	return dhclient_start (client, info_only ? "-S" : "-N", duid, FALSE);
 }
 
 static void
@@ -620,7 +653,7 @@ stop (NMDHCPClient *client, gboolean release, const GByteArray *duid)
 	if (release) {
 		GPid rpid;
 
-		rpid = dhclient_start (client, NULL, TRUE);
+		rpid = dhclient_start (client, NULL, duid, TRUE);
 		if (rpid > 0) {
 			/* Wait a few seconds for the release to happen */
 			nm_dhcp_client_stop_pid (rpid, nm_dhcp_client_get_iface (client), 5);
@@ -642,6 +675,7 @@ get_duid (NMDHCPClient *client)
 	                                    TRUE);
 	nm_log_dbg (LOGD_DHCP, "Looking for DHCPv6 DUID in '%s'.", leasefile);
 	duid = nm_dhcp_dhclient_read_duid (leasefile, &error);
+	priv->lease_duid_found = !!duid;
 	g_free (leasefile);
 
 	if (error) {
@@ -656,6 +690,7 @@ get_duid (NMDHCPClient *client)
 		/* Otherwise read the default machine-wide DUID */
 		nm_log_dbg (LOGD_DHCP, "Looking for default DHCPv6 DUID in '%s'.", priv->def_leasefile);
 		duid = nm_dhcp_dhclient_read_duid (priv->def_leasefile, &error);
+		priv->default_duid_found = !!duid;
 		if (error) {
 			nm_log_warn (LOGD_DHCP, "Failed to read leasefile '%s': (%d) %s",
 			             priv->def_leasefile,