Make host name DHCP option configurable.

Diff from hagen@sdf.org, tweaks by me.
OK phessler
testing & OK bket

7 files changed, 110 insertions, 16 deletions

diff --git a/sbin/dhcpleased/dhcpleased.c b/sbin/dhcpleased/dhcpleased.c
index 497ca5a0a79..3972d2a7365 100644
--- a/sbin/dhcpleased/dhcpleased.c
+++ b/sbin/dhcpleased/dhcpleased.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcpleased.c,v 1.22 2021/12/13 11:02:26 florian Exp $	*/
+/*	$OpenBSD: dhcpleased.c,v 1.23 2022/01/04 06:20:37 florian Exp $	*/
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -732,6 +732,9 @@ main_imsg_send_config(struct dhcpleased_conf *xconf)
 		    iface_conf->c_id, iface_conf->c_id_len);
 		main_imsg_compose_engine(IMSG_RECONF_C_ID, -1,
 		    iface_conf->c_id, iface_conf->c_id_len);
+		if (iface_conf->h_name != NULL)
+			main_imsg_compose_frontend(IMSG_RECONF_H_NAME, -1,
+			    iface_conf->h_name, strlen(iface_conf->h_name) + 1);
 	}
 
 	/* Config is now complete. */
@@ -1224,6 +1227,7 @@ merge_config(struct dhcpleased_conf *conf, struct dhcpleased_conf *xconf)
 		SIMPLEQ_REMOVE_HEAD(&conf->iface_list, entry);
 		free(iface_conf->vc_id);
 		free(iface_conf->c_id);
+		free(iface_conf->h_name);
 		free(iface_conf);
 	}
 
diff --git a/sbin/dhcpleased/dhcpleased.conf.5 b/sbin/dhcpleased/dhcpleased.conf.5
index 31b369bdc52..708462d81f1 100644
--- a/sbin/dhcpleased/dhcpleased.conf.5
+++ b/sbin/dhcpleased/dhcpleased.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: dhcpleased.conf.5,v 1.8 2021/09/21 17:23:24 florian Exp $
+.\"	$OpenBSD: dhcpleased.conf.5,v 1.9 2022/01/04 06:20:37 florian Exp $
 .\"
 .\" Copyright (c) 2018, 2021 Florian Obser <florian@openbsd.org>
 .\" Copyright (c) 2005 Esben Norby <norby@openbsd.org>
@@ -18,7 +18,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: September 21 2021 $
+.Dd $Mdocdate: January 4 2022 $
 .Dt DHCPLEASED.CONF 5
 .Os
 .Sh NAME
@@ -98,6 +98,13 @@ with hardware type 0 would be configured as:
 .Bd -literal -offset indent
 send client id "\e0foobar"
 .Ed
+.It Ic send host name Ar host-name
+Send the DHCP client host name option with a value of
+.Ar host-name .
+The default is to send the name of the host.
+.It Ic send no host name
+Do not send a DHCP host name option.
+The default is to send a DHCP host name option with the name of the host.
 .It Ic send vendor class id Ar vendor-class-id
 Send the DHCP vendor class identifier option with a value of
 .Ar vendor-class-id .
diff --git a/sbin/dhcpleased/dhcpleased.h b/sbin/dhcpleased/dhcpleased.h
index 02121c19841..a987b02d50d 100644
--- a/sbin/dhcpleased/dhcpleased.h
+++ b/sbin/dhcpleased/dhcpleased.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcpleased.h,v 1.12 2021/12/09 16:20:12 florian Exp $	*/
+/*	$OpenBSD: dhcpleased.h,v 1.13 2022/01/04 06:20:37 florian Exp $	*/
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -203,6 +203,7 @@ enum imsg_type {
 	IMSG_RECONF_IFACE,
 	IMSG_RECONF_VC_ID,
 	IMSG_RECONF_C_ID,
+	IMSG_RECONF_H_NAME,
 	IMSG_RECONF_END,
 #endif	/* SMALL */
 	IMSG_SEND_DISCOVER,
@@ -253,6 +254,7 @@ struct iface_conf {
 	int				 vc_id_len;
 	uint8_t				*c_id;
 	int				 c_id_len;
+	char				*h_name;
 	int				 ignore;
 	struct in_addr			 ignore_servers[MAX_SERVERS];
 	int				 ignore_servers_len;
diff --git a/sbin/dhcpleased/engine.c b/sbin/dhcpleased/engine.c
index 13bea5b89fd..fa25fbbf0b9 100644
--- a/sbin/dhcpleased/engine.c
+++ b/sbin/dhcpleased/engine.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: engine.c,v 1.34 2021/12/18 10:34:19 florian Exp $	*/
+/*	$OpenBSD: engine.c,v 1.35 2022/01/04 06:20:37 florian Exp $	*/
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -480,6 +480,7 @@ engine_dispatch_main(int fd, short event, void *bula)
 			iface_conf->vc_id_len = 0;
 			iface_conf->c_id = NULL;
 			iface_conf->c_id_len = 0;
+			iface_conf->h_name = NULL;
 			SIMPLEQ_INSERT_TAIL(&nconf->iface_list,
 			    iface_conf, entry);
 			break;
@@ -511,6 +512,18 @@ engine_dispatch_main(int fd, short event, void *bula)
 			    IMSG_DATA_SIZE(imsg));
 			iface_conf->c_id_len = IMSG_DATA_SIZE(imsg);
 			break;
+		case IMSG_RECONF_H_NAME:
+			if (iface_conf == NULL)
+				fatal("IMSG_RECONF_H_NAME without "
+				    "IMSG_RECONF_IFACE");
+			if (((char *)imsg.data)[IMSG_DATA_SIZE(imsg) - 1] !=
+			    '\0')
+				fatalx("Invalid hostname");
+			if (IMSG_DATA_SIZE(imsg) > 256)
+				fatalx("Invalid hostname");
+			if ((iface_conf->h_name = strdup(imsg.data)) == NULL)
+				fatal(NULL);
+			break;
 		case IMSG_RECONF_END: {
 			struct dhcpleased_iface	*iface;
 			int			*ifaces;
diff --git a/sbin/dhcpleased/frontend.c b/sbin/dhcpleased/frontend.c
index 90b6c20d7bd..58c6153793f 100644
--- a/sbin/dhcpleased/frontend.c
+++ b/sbin/dhcpleased/frontend.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: frontend.c,v 1.27 2021/12/13 11:03:23 florian Exp $	*/
+/*	$OpenBSD: frontend.c,v 1.28 2022/01/04 06:20:37 florian Exp $	*/
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -361,6 +361,7 @@ frontend_dispatch_main(int fd, short event, void *bula)
 			iface_conf->vc_id_len = 0;
 			iface_conf->c_id = NULL;
 			iface_conf->c_id_len = 0;
+			iface_conf->h_name = NULL;
 			SIMPLEQ_INSERT_TAIL(&nconf->iface_list,
 			    iface_conf, entry);
 			break;
@@ -392,6 +393,18 @@ frontend_dispatch_main(int fd, short event, void *bula)
 			    IMSG_DATA_SIZE(imsg));
 			iface_conf->c_id_len = IMSG_DATA_SIZE(imsg);
 			break;
+		case IMSG_RECONF_H_NAME:
+			if (iface_conf == NULL)
+				fatal("IMSG_RECONF_H_NAME without "
+				    "IMSG_RECONF_IFACE");
+			if (((char *)imsg.data)[IMSG_DATA_SIZE(imsg) - 1] !=
+			    '\0')
+				fatalx("Invalid hostname");
+			if (IMSG_DATA_SIZE(imsg) > 256)
+				fatalx("Invalid hostname");
+			if ((iface_conf->h_name = strdup(imsg.data)) == NULL)
+				fatal(NULL);
+			break;
 		case IMSG_RECONF_END: {
 			int	 i;
 			int	*ifaces;
@@ -904,7 +917,7 @@ build_packet(uint8_t message_type, char *if_name, uint32_t xid,
 	static uint8_t	 dhcp_cookie[] = DHCP_COOKIE;
 	static uint8_t	 dhcp_message_type[] = {DHO_DHCP_MESSAGE_TYPE, 1,
 		DHCPDISCOVER};
-	static uint8_t	 dhcp_hostname[255] = {DHO_HOST_NAME, 0 /*, ... */};
+	static uint8_t	 dhcp_hostname[255 + 2] = {DHO_HOST_NAME, 0 /*, ... */};
 	static uint8_t	 dhcp_client_id[] = {DHO_DHCP_CLIENT_IDENTIFIER, 7,
 		HTYPE_ETHER, 0, 0, 0, 0, 0, 0};
 	static uint8_t	 dhcp_req_list[] = {DHO_DHCP_PARAMETER_REQUEST_LIST,
@@ -944,12 +957,27 @@ build_packet(uint8_t message_type, char *if_name, uint32_t xid,
 	p += sizeof(dhcp_cookie);
 	memcpy(p, dhcp_message_type, sizeof(dhcp_message_type));
 	p += sizeof(dhcp_message_type);
-	if (gethostname(dhcp_hostname + 2, sizeof(dhcp_hostname) - 2) == 0) {
-		if ((c = strchr(dhcp_hostname + 2, '.')) != NULL)
-			*c = '\0';
-		dhcp_hostname[1] = strlen(dhcp_hostname + 2);
-		memcpy(p, dhcp_hostname, dhcp_hostname[1] + 2);
-		p += dhcp_hostname[1] + 2;
+
+#ifndef SMALL
+	if (iface_conf != NULL && iface_conf->h_name != NULL) {
+		if (iface_conf->h_name[0] != '\0') {
+			dhcp_hostname[1] = strlen(iface_conf->h_name);
+			memcpy(dhcp_hostname + 2, iface_conf->h_name,
+			    strlen(iface_conf->h_name));
+			memcpy(p, dhcp_hostname, dhcp_hostname[1] + 2);
+			p += dhcp_hostname[1] + 2;
+		}
+	} else
+#endif /* SMALL */
+	{
+		if (gethostname(dhcp_hostname + 2,
+		    sizeof(dhcp_hostname) - 2) == 0) {
+			if ((c = strchr(dhcp_hostname + 2, '.')) != NULL)
+				*c = '\0';
+			dhcp_hostname[1] = strlen(dhcp_hostname + 2);
+			memcpy(p, dhcp_hostname, dhcp_hostname[1] + 2);
+			p += dhcp_hostname[1] + 2;
+		}
 	}
 
 #ifndef SMALL
@@ -1237,6 +1265,10 @@ iface_conf_cmp(struct iface_conf *a, struct iface_conf *b)
 		return 1;
 	if (memcmp(a->c_id, b->c_id, a->c_id_len) != 0)
 		return 1;
+	if (a->h_name == NULL ||  b->h_name == NULL)
+		return 1;
+	if (strcmp(a->h_name, b->h_name) != 0)
+		return 1;
 	if (a->ignore != b->ignore)
 		return 1;
 	if (a->ignore_servers_len != b->ignore_servers_len)
diff --git a/sbin/dhcpleased/parse.y b/sbin/dhcpleased/parse.y
index 33c2dc7f335..0031dcd095e 100644
--- a/sbin/dhcpleased/parse.y
+++ b/sbin/dhcpleased/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.5 2021/10/15 15:01:27 naddy Exp $	*/
+/*	$OpenBSD: parse.y,v 1.6 2022/01/04 06:20:37 florian Exp $	*/
 
 /*
  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
@@ -108,7 +108,8 @@ typedef struct {
 
 %}
 
-%token	DHCP_IFACE ERROR SEND VENDOR CLASS ID CLIENT IGNORE DNS ROUTES
+%token	DHCP_IFACE ERROR SEND VENDOR CLASS ID CLIENT IGNORE DNS ROUTES HOST NAME
+%token	NO
 
 %token	<v.string>	STRING
 %token	<v.number>	NUMBER
@@ -274,6 +275,30 @@ ifaceoptsl	: SEND VENDOR CLASS ID STRING {
 			iface_conf->c_id[0] = DHO_DHCP_CLIENT_IDENTIFIER;
 			iface_conf->c_id[1] = iface_conf->c_id_len - 2;
 		}
+		| SEND HOST NAME STRING {
+			if (iface_conf->h_name != NULL) {
+				free($4);
+				yyerror("host name already set");
+				YYERROR;
+			}
+			if (strlen($4) > 255) {
+				free($4);
+				yyerror("host name too long");
+				YYERROR;
+			}
+			iface_conf->h_name = $4;
+		}
+		| SEND NO HOST NAME {
+			if (iface_conf->h_name != NULL) {
+				yyerror("host name already set");
+				YYERROR;
+			}
+
+			if ((iface_conf->h_name = strdup("")) == NULL) {
+				yyerror("malloc");
+				YYERROR;
+			}
+		}
 		| IGNORE ROUTES {
 			iface_conf->ignore |= IGN_ROUTES;
 		}
@@ -337,9 +362,12 @@ lookup(char *s)
 		{"class",		CLASS},
 		{"client",		CLIENT},
 		{"dns",			DNS},
+		{"host",		HOST},
 		{"id",			ID},
 		{"ignore",		IGNORE},
 		{"interface",		DHCP_IFACE},
+		{"name",		NAME},
+		{"no",			NO},
 		{"routes",		ROUTES},
 		{"send",		SEND},
 		{"vendor",		VENDOR},
diff --git a/sbin/dhcpleased/printconf.c b/sbin/dhcpleased/printconf.c
index 5de78699188..076fe2ec0ad 100644
--- a/sbin/dhcpleased/printconf.c
+++ b/sbin/dhcpleased/printconf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: printconf.c,v 1.3 2021/09/20 11:46:22 florian Exp $	*/
+/*	$OpenBSD: printconf.c,v 1.4 2022/01/04 06:20:37 florian Exp $	*/
 
 /*
  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
@@ -106,6 +106,14 @@ print_config(struct dhcpleased_conf *conf)
 	SIMPLEQ_FOREACH(iface, &conf->iface_list, entry) {
 		printf("interface %s {\n", iface->name);
 		print_dhcp_options("\t", iface->c_id, iface->c_id_len);
+		if (iface->h_name != NULL) {
+			if (iface->h_name[0] == '\0')
+				printf("\tsend no host name\n");
+			else {
+				printf("\tsend host name \"%s\"\n",
+				    iface->h_name);
+			}
+		}
 		print_dhcp_options("\t", iface->vc_id, iface->vc_id_len);
 		if (iface->ignore & IGN_DNS)
 			printf("\tignore dns\n");