git: 461ccb55d50c - main - dhclient: add ability to ignore options in offers

The branch main has been updated by allanjude:

URL: https://cgit.FreeBSD.org/src/commit/?id=461ccb55d50ccf1b5bcfe1310fe32d72f8b0ecdd

commit 461ccb55d50ccf1b5bcfe1310fe32d72f8b0ecdd
Author:     Rob Norris <rob.norris@klarasystems.com>
AuthorDate: 2023-03-14 22:07:18 +0000
Commit:     Allan Jude <allanjude@FreeBSD.org>
CommitDate: 2023-04-10 23:13:18 +0000

    dhclient: add ability to ignore options in offers
    
    A machine might exist on multiple networks, all of which offer, say, default
    routes or name servers. There's no easy way to indicate in the config
    that those options are only valid for a single interface.
    
    Now, we can write:
    
        interface "lan0" {
          request routers;
          require routers;
        }
        interface "lan1" {
          ignore routers;
        }
    
    And only take action on default routes offered on lan0.
    
    Tested by:      Jose Luis Duran <jlduran at gmail dot com>
    MFC after:      2 months
    Reviewed by:    allanjude, imp
    Sponsored by:   Zenith Electronics LLC
    Sponsored by:   Klara, Inc.
    Pull Request:   #693
---
 sbin/dhclient/clparse.c       |  4 ++++
 sbin/dhclient/conflex.c       |  2 ++
 sbin/dhclient/dhclient.c      | 13 +++++++++++--
 sbin/dhclient/dhclient.conf.5 |  7 ++++++-
 sbin/dhclient/dhcpd.h         |  1 +
 sbin/dhclient/dhctoken.h      |  1 +
 6 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/sbin/dhclient/clparse.c b/sbin/dhclient/clparse.c
index c7b02a073aa3..295a800a7328 100644
--- a/sbin/dhclient/clparse.c
+++ b/sbin/dhclient/clparse.c
@@ -186,6 +186,7 @@ read_client_leases(void)
  *	hardware-declaration |
  *	REQUEST option-list |
  *	REQUIRE option-list |
+ *	IGNORE option-list |
  *	TIMEOUT number |
  *	RETRY number |
  *	REBOOT number |
@@ -249,6 +250,9 @@ parse_client_statement(FILE *cfile, struct interface_info *ip,
 		    sizeof(config->required_options));
 		parse_option_list(cfile, config->required_options);
 		return;
+	case IGNORE:
+		parse_option_list(cfile, config->ignored_options);
+		return;
 	case TIMEOUT:
 		parse_lease_time(cfile, &config->timeout);
 		return;
diff --git a/sbin/dhclient/conflex.c b/sbin/dhclient/conflex.c
index c11c9189527e..3a6824a9a815 100644
--- a/sbin/dhclient/conflex.c
+++ b/sbin/dhclient/conflex.c
@@ -413,6 +413,8 @@ intern(char *atom, int dfv)
 			return (HOSTNAME);
 		break;
 	case 'i':
+		if (!strcasecmp(atom + 1, "gnore"))
+			return (IGNORE);
 		if (!strcasecmp(atom + 1, "nitial-interval"))
 			return (INITIAL_INTERVAL);
 		if (!strcasecmp(atom + 1, "nterface"))
diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index da9a567fad04..4261251b6b78 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1039,7 +1039,6 @@ dhcpoffer(struct packet *packet)
 
 	note("%s from %s", name, piaddr(packet->client_addr));
 
-
 	/* If this lease doesn't supply the minimum required parameters,
 	   blow it off. */
 	for (i = 0; ip->client->config->required_options[i]; i++) {
@@ -1141,8 +1140,9 @@ dhcpoffer(struct packet *packet)
 struct client_lease *
 packet_to_lease(struct packet *packet)
 {
+	struct interface_info *ip = packet->interface;
 	struct client_lease *lease;
-	int i;
+	int i, j;
 
 	lease = malloc(sizeof(struct client_lease));
 
@@ -1156,6 +1156,15 @@ packet_to_lease(struct packet *packet)
 	/* Copy the lease options. */
 	for (i = 0; i < 256; i++) {
 		if (packet->options[i].len) {
+			int ignored = 0;
+			for (j = 0; ip->client->config->ignored_options[j]; j++)
+				if (i ==
+				    ip->client->config->ignored_options[j]) {
+					ignored = 1;
+					break;
+				}
+			if (ignored)
+			    continue;
 			lease->options[i].data =
 			    malloc(packet->options[i].len + 1);
 			if (!lease->options[i].data) {
diff --git a/sbin/dhclient/dhclient.conf.5 b/sbin/dhclient/dhclient.conf.5
index 14a0de4111dd..39a00fd0f207 100644
--- a/sbin/dhclient/dhclient.conf.5
+++ b/sbin/dhclient/dhclient.conf.5
@@ -38,7 +38,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 21, 2021
+.Dd March 17, 2023
 .Dt DHCLIENT.CONF 5
 .Os
 .Sh NAME
@@ -200,6 +200,11 @@ option other than the default requested lease time, which is two hours.
 The other obvious use for this statement is to send information to the server
 that will allow it to differentiate between this client and other
 clients or kinds of clients.
+.It Ic ignore Oo Ar option Oc Oo , Ar ... option Oc ;
+The
+.Ic ignore
+statement causes the client to disregard the specified options in any offer
+received, as though the server had never sent them at all.
 .El
 .Sh OPTION MODIFIERS
 In some cases, a client may receive option data from the server which
diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index b151daa90a1c..580fdabaf367 100644
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -159,6 +159,7 @@ struct client_config {
 	u_int8_t		 required_options[256];
 	u_int8_t		 requested_options[256];
 	int			 requested_option_count;
+	u_int8_t		 ignored_options[256];
 	u_int			 vlan_pcp;
 	time_t			 timeout;
 	time_t			 initial_interval;
diff --git a/sbin/dhclient/dhctoken.h b/sbin/dhclient/dhctoken.h
index c929307c7e06..dc8008e23be9 100644
--- a/sbin/dhclient/dhctoken.h
+++ b/sbin/dhclient/dhctoken.h
@@ -134,6 +134,7 @@
 #define TOKEN_NOT	334
 #define ALWAYS_REPLY_RFC1048 335
 #define VLAN_PCP	336
+#define IGNORE		337
 
 #define is_identifier(x)	((x) >= FIRST_TOKEN &&	\
 				 (x) != STRING &&	\