From: Roy Marples <roy@marples.name>
Date: Mon, 19 Oct 2015 09:19:45 +0000 (+0000)
Subject: Introduce the optional option type, which allows embedded options to be
X-Git-Tag: v6.9.4~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ecdbb919fa4d05a8b1303848ec99a67c16b063dd;p=thirdparty%2Fdhcpcd.git

Introduce the optional option type, which allows embedded options to be
optional. A good example of this is the Client FQDN string in the DHCP
Client FQDN option as a NULL value indicates the server has no idea
what the FQDN should be.
---

diff --git a/dhcp-common.c b/dhcp-common.c
index 47bf47d9..285e29c0 100644
--- a/dhcp-common.c
+++ b/dhcp-common.c
@@ -898,9 +898,10 @@ dhcp_envoption(struct dhcpcd_ctx *ctx, char **env, const char *prefix,
 		if (eo == -1) {
 			if (env == NULL)
 				logger(ctx, LOG_ERR,
-				    "%s: %s: malformed embedded option %d:%d",
+				    "%s: %s: malformed embedded option"
+				    " %d:%d/%zu",
 				    ifname, __func__, opt->option,
-				    eopt->option);
+				    eopt->option, i);
 			goto out;
 		}
 		if (eo == 0) {
@@ -908,15 +909,13 @@ dhcp_envoption(struct dhcpcd_ctx *ctx, char **env, const char *prefix,
 			 * data for it.
 			 * This may not be an error as some options like
 			 * DHCP FQDN in RFC4702 have a string as the last
-			 * option which is optional.
-			 * FIXME: Add an flag to the options to indicate
-			 * wether this is allowable or not. */
+			 * option which is optional. */
 			if (env == NULL &&
-			    (ol != 0 || i + 1 < opt->embopts_len))
+			    (ol != 0 || !(eopt->type & OPTIONAL)))
 				logger(ctx, LOG_ERR,
-				    "%s: %s: malformed embedded option %d:%d",
+				    "%s: %s: missing embedded option %d:%d/%zu",
 				    ifname, __func__, opt->option,
-				    eopt->option);
+				    eopt->option, i);
 			goto out;
 		}
 		/* Use the option prefix if the embedded option
diff --git a/dhcp-common.h b/dhcp-common.h
index 3899fc7f..37451b06 100644
--- a/dhcp-common.h
+++ b/dhcp-common.h
@@ -52,7 +52,7 @@
 #define RFC3361		(1 << 9)
 #define RFC1035		(1 << 10)
 #define RFC3442		(1 << 11)
-/* unassigned		(1 << 12) */
+#define OPTIONAL	(1 << 12)
 #define ADDRIPV6	(1 << 13)
 #define BINHEX		(1 << 14)
 #define FLAG		(1 << 15)
diff --git a/dhcpcd-definitions.conf b/dhcpcd-definitions.conf
index 5c8b6225..21552b8e 100644
--- a/dhcpcd-definitions.conf
+++ b/dhcpcd-definitions.conf
@@ -114,7 +114,7 @@ embed		byte			rcode2
 # RFC1035 encoded.
 # The server MUST use the encoding as specified by the client as noted
 # in RFC4702 Section 2.1.
-embed		domain			fqdn
+embed		optional domain		fqdn
 
 # Option 82 is for Relay Agents and DHCP servers
 
diff --git a/dhcpcd.conf.5.in b/dhcpcd.conf.5.in
index 5ef1e3c3..a7f0acd5 100644
--- a/dhcpcd.conf.5.in
+++ b/dhcpcd.conf.5.in
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd September 15, 2015
+.Dd October 19, 2015
 .Dt DHCPCD.CONF 5
 .Os
 .Sh NAME
@@ -735,6 +735,10 @@ Requests the option by default without having to be specified in user
 configuration
 .It Ic norequest
 This option cannot be requested, regardless of user configuration
+.It Ic optional
+This option is optional.
+Only makes sense for embedded options where like the client FQDN option where
+the FQDN string itself is optional.
 .It Ic index
 The option can appear more than once and will be indexed.
 .It Ic array
diff --git a/if-options.c b/if-options.c
index 40753fc4..71d2cb47 100644
--- a/if-options.c
+++ b/if-options.c
@@ -1599,6 +1599,17 @@ err_sla:
 			}
 			*fp++ = '\0';
 		}
+		if (strcasecmp(arg, "optional") == 0) {
+			t |= OPTIONAL;
+			arg = strskipwhite(fp);
+			fp = strwhite(arg);
+			if (fp == NULL) {
+				logger(ctx, LOG_ERR,
+				    "incomplete optional type");
+				return -1;
+			}
+			*fp++ = '\0';
+		}
 		if (strcasecmp(arg, "index") == 0) {
 			t |= INDEX;
 			arg = strskipwhite(fp);