From: Roy Marples <roy@marples.name>
Date: Thu, 25 Jul 2013 15:10:16 +0000 (+0000)
Subject: Add the option hostname_short, which will force the sending of the
X-Git-Tag: v6.0.4~5
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d6a186547664756fd51ca511b4bf821b279068e8;p=thirdparty%2Fdhcpcd.git

Add the option hostname_short, which will force the sending of the
short hostname so DDNS will always work, even if the hostname domain
is different from the DHCP servers.

Change hostname_fqdn to true/false/unset value.
unset means use what the DHCP server supplies
 (DHCPv4/DHCPv6 maybe inconsistent depending on server setup)
true/false force the hostname to be either a FQDN or a short name.
---

diff --git a/common.c b/common.c
index 1740e29e..4bf52bad 100644
--- a/common.c
+++ b/common.c
@@ -136,8 +136,9 @@ set_nonblock(int fd)
 }
 
 const char *
-get_hostname(void)
+get_hostname(int short_hostname)
 {
+	char *p;
 
 	gethostname(hostname_buffer, sizeof(hostname_buffer));
 	hostname_buffer[sizeof(hostname_buffer) - 1] = '\0';
@@ -146,6 +147,13 @@ get_hostname(void)
 	    strncmp(hostname_buffer, "localhost.", strlen("localhost.")) == 0 ||
 	    hostname_buffer[0] == '.')
 		return NULL;
+
+	if (short_hostname) {
+		p = strchr(hostname_buffer, '.');
+		if (p)
+			*p = '\0';
+	}
+
 	return hostname_buffer;
 }
 
diff --git a/common.h b/common.h
index b7851cb4..392125a2 100644
--- a/common.h
+++ b/common.h
@@ -100,7 +100,7 @@
 int set_cloexec(int);
 int set_nonblock(int);
 char *get_line(FILE * __restrict);
-const char *get_hostname(void);
+const char *get_hostname(int);
 extern int clock_monotonic;
 int get_monotonic(struct timeval *);
 ssize_t setvar(char ***, const char *, const char *, const char *);
diff --git a/dhcp.c b/dhcp.c
index 06ed6111..30c1ecd6 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -845,7 +845,6 @@ make_message(struct dhcp_message **message,
 	uint32_t ul;
 	uint16_t sz;
 	size_t len;
-	const char *hp;
 	const struct dhcp_opt *opt;
 	const struct if_options *ifo = iface->options;
 	const struct dhcp_state *state = D_CSTATE(iface);
@@ -987,7 +986,8 @@ make_message(struct dhcp_message **message,
 		}
 
 		if (ifo->hostname[0] == '\0')
-			hostname = get_hostname();
+			hostname = get_hostname(ifo->options &
+			    DHCPCD_HOSTNAME_SHORT ? 1 : 0);
 		else
 			hostname = ifo->hostname;
 		if (ifo->fqdn != FQDN_DISABLE) {
@@ -1018,17 +1018,7 @@ make_message(struct dhcp_message **message,
 			}
 		} else if (ifo->options & DHCPCD_HOSTNAME && hostname) {
 			*p++ = DHO_HOSTNAME;
-			/*
-			 * Regardless of RFC2132, we should always send a
-			 * hostname upto the first dot (the short hostname) as
-			 * a FQDN confuses some DHCP servers when updating DNS.
-			 * The FQDN option should be used if a FQDN is wanted.
-			 */
-			hp = strchr(hostname, '.');
-			if (hp)
-				len = hp - hostname;
-			else
-				len = strlen(hostname);
+			len = strlen(hostname);
 			*p++ = len;
 			memcpy(p, hostname, len);
 			p += len;
diff --git a/dhcp6.c b/dhcp6.c
index 9e95b279..3cf69f39 100644
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -398,7 +398,8 @@ dhcp6_makemessage(struct interface *ifp)
 		if (fqdn == FQDN_DISABLE)
 			fqdn = FQDN_BOTH;
 		if (ifo->hostname[0] == '\0')
-			hostname = get_hostname();
+			hostname = get_hostname(ifo->options &
+			    DHCPCD_HOSTNAME_SHORT ? 1 : 0);
 		else
 			hostname = ifo->hostname;
 	}
diff --git a/dhcpcd-hooks/30-hostname b/dhcpcd-hooks/30-hostname
index 42120ceb..6098f620 100644
--- a/dhcpcd-hooks/30-hostname
+++ b/dhcpcd-hooks/30-hostname
@@ -1,7 +1,9 @@
 # Set the hostname from DHCP data if required
 
-# Generally we should not set the system hostname to be fully qualified
-: ${hostname_fqdn:=false}
+# Set one of the below to override the DHCP supplied hostname information
+# to be either a short hostname or a FQDN.
+#hostname_fqdn=false
+#hostname_fqdn=true
 
 # Some systems don't have hostname(1)
 _hostname()
@@ -41,7 +43,7 @@ _hostname()
 
 need_hostname()
 {
-	local hostname hfqdn
+	local hostname hfqdn=false hshort=false
 
 	case "$force_hostname" in
 	[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) return 0;;
@@ -54,13 +56,14 @@ need_hostname()
 	
 	case "$hostname_fqdn" in
 	[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1)	hfqdn=true;;
-	*)					hfqdn=false;;
+	"")					;;
+	*)					hshort=true;;
 	esac
 
 	if [ -n "$old_fqdn" ]; then
-		if ${hfqdn}; then
+		if ${hfqdn} || ! ${hsort}; then
 			[ "$hostname" = "$old_fqdn" ]
-		else	
+		else
 			[ "$hostname" = "${old_fqdn%%.*}" ]
 		fi
 	elif [ -n "$old_host_name" ]; then
@@ -73,8 +76,10 @@ need_hostname()
 			else
 				[ "$hostname" = "$old_host_name" ]
 			fi
-		else
+		elif ${hshort}; then
 			[ "$hostname" = "${old_host_name%%.*}" ]
+		else
+			[ "$hostname" = "$old_host_name" ]
 		fi
 	fi
 }
@@ -101,7 +106,7 @@ set_hostname()
 	esac
 
 	if [ -n "$new_fqdn" ]; then
-		if ${hfqdn}; then
+		if ${hfqdn} || ! ${hsort}; then
 			try_hostname "$new_fqdn"
 		else
 			try_hostname "${new_fqdn%%.*}"
@@ -115,8 +120,10 @@ set_hostname()
 			else
 				try_hostname "$new_host_name"
 			fi
-		else
+		elif ${hshort}; then
 			try_hostname "${new_host_name%%.*}"
+		else
+			try_hostname "$new_host_name"
 		fi
 	fi
 }
diff --git a/dhcpcd.conf.5.in b/dhcpcd.conf.5.in
index f2f7fe58..cd14d3d9 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 June 19, 2013
+.Dd July 25, 2013
 .Dt DHCPCD.CONF 5 SMM
 .Os
 .Sh NAME
@@ -133,6 +133,10 @@ is an empty string then the current system hostname is sent.
 If
 .Ar hostname
 is a FQDN (ie, contains a .) then it will be encoded as such.
+.It Ic hostname_short
+Sends the short hostname to the DHCP server instead of the FQDN.
+This is useful because DHCP servers will not register the FQDN in their
+DNS if the domain part does not match theirs.
 .It Ic ia_na Op Ar iaid
 Request a DHCPv6 Normal Address for
 .Ar iaid .
diff --git a/if-options.c b/if-options.c
index d22af1be..9f359954 100644
--- a/if-options.c
+++ b/if-options.c
@@ -67,6 +67,7 @@ unsigned long long options = 0;
 #define O_IA_NA			O_BASE + 10
 #define O_IA_TA			O_BASE + 11
 #define O_IA_PD			O_BASE + 12
+#define O_HOSTNAME_SHORT	O_BASE + 13
 
 const struct option cf_options[] = {
 	{"background",      no_argument,       NULL, 'b'},
@@ -128,6 +129,7 @@ const struct option cf_options[] = {
 	{"ia_na",           no_argument,       NULL, O_IA_NA},
 	{"ia_ta",           no_argument,       NULL, O_IA_TA},
 	{"ia_pd",           no_argument,       NULL, O_IA_PD},
+	{"hostname_short",  no_argument,       NULL, O_HOSTNAME_SHORT},
 	{NULL,              0,                 NULL, '\0'}
 };
 
@@ -1079,6 +1081,9 @@ got_iaid:
 			}
 		}
 		break;
+	case O_HOSTNAME_SHORT:
+		ifo->options |= DHCPCD_HOSTNAME_SHORT;
+		break;
 #endif
 	default:
 		return 0;
diff --git a/if-options.h b/if-options.h
index 06cccdf0..a00dd769 100644
--- a/if-options.h
+++ b/if-options.h
@@ -94,6 +94,7 @@
 #define DHCPCD_IA_FORCED		(1ULL << 40)
 #define DHCPCD_STOPPING			(1ULL << 41)
 #define DHCPCD_DEPARTED			(1ULL << 42)
+#define DHCPCD_HOSTNAME_SHORT		(1ULL << 43)
 
 extern const struct option cf_options[];