Implement --dhcp-duid

CHANGELOG

@@ -7,6 +7,8 @@ version 2.61
 	    Add ra-names DHCPv6 keyword which adds AAAA records
 	    for dual-stack hosts which get IPv6 addresses via SLAAC.
 
+	    Add --dhcp-duid to allow DUID-EN uids to be used.
+
 
 version 2.60
             Fix compilation problem in Mac OS X Lion. Thanks to Olaf

man/dnsmasq.8

@@ -1042,6 +1042,16 @@ the tags used to determine them.
 .B \-l, --dhcp-leasefile=<path>
 Use the specified file to store DHCP lease information.
 .TP 
+.B --dhcp-duid=<enterprise-id>,<uid>
+(IPv6 only) Specify the server persistent UID which the DHCPv6 server
+will use. This option is not normally required as dnsmasq creates a
+DUID automatically when it is first needed. When given, this option
+provides dnsmasq the data required to create a DUID-EN type DUID. Note
+that once set, the DUID is stored in the lease database, so to change between DUID-EN and
+automatically created DUIDs or vice-versa, the lease database must be
+re-intialised. The enterprise-id is assigned by IANA, and the uid is a
+string of hex octets unique to a particular device.
+.TP
 .B \-6 --dhcp-script=<path>
 Whenever a new DHCP lease is created, or an old one destroyed, the
 executable specified by this option is run.  <path>

src/dhcp6.c

@@ -365,13 +365,26 @@ struct dhcp_config *find_config6(struct dhcp_config *configs,
 
 void make_duid(time_t now)
 {
-  /* rebase epoch to 1/1/2000 */
+  if (daemon->duid_config)
-  time_t newnow = now - 946684800;
+    {
+      unsigned char *p;
       
-  iface_enumerate(AF_LOCAL, &newnow, make_duid1);
+      daemon->duid = p = safe_malloc(daemon->duid_config_len + 6);
+      daemon->duid_len = daemon->duid_config_len + 6;
+      PUTSHORT(2, p); /* DUID_EN */
+      PUTLONG(daemon->duid_enterprise, p);
+      memcpy(p, daemon->duid_config, daemon->duid_config_len);
+    }
+  else
+    {
+      /* rebase epoch to 1/1/2000 */
+      time_t newnow = now - 946684800;
       
-  if(!daemon->duid)
+      iface_enumerate(AF_LOCAL, &newnow, make_duid1);
-    die("Cannot create DHCPv6 server DUID: %s", NULL, EC_MISC);
+      
+      if(!daemon->duid)
+	die("Cannot create DHCPv6 server DUID: %s", NULL, EC_MISC);
+    }
 }
 
 static int make_duid1(int index, unsigned int type, char *mac, size_t maclen, void *parm)

src/dnsmasq.c

@@ -196,7 +196,7 @@ int main (int argc, char **argv)
 #ifdef HAVE_DHCP
   /* after netlink_init */
   if (daemon->dhcp || daemon->dhcp6)
-    lease_find_interfaces();
+    lease_find_interfaces(now);
 #endif
 
   if (!enumerate_interfaces())

src/dnsmasq.h

@@ -731,6 +731,8 @@ extern struct daemon {
   struct tftp_prefix *if_prefix; /* per-interface TFTP prefixes */
   struct interface_list *tftp_interfaces; /* interfaces for limited TFTP service */
   int tftp_unlimited;
+  unsigned int duid_enterprise, duid_config_len;
+  unsigned char *duid_config;
 
   /* globally used stuff for DNS */
   char *packet; /* packet buffer */
@@ -956,7 +958,7 @@ void lease_prune(struct dhcp_lease *target, time_t now);
 void lease_update_from_configs(void);
 int do_script_run(time_t now);
 void rerun_scripts(void);
-void lease_find_interfaces(void);
+void lease_find_interfaces(time_t now);
 #ifdef HAVE_SCRIPT
 void lease_add_extradata(struct dhcp_lease *lease, unsigned char *data, 
 			 unsigned int len, int delim);

src/lease.c

@@ -175,16 +175,6 @@ void lease_init(time_t now)
   file_dirty = 0;
   lease_prune(NULL, now);
   dns_dirty = 1;
-
-#ifdef HAVE_DHCP6  
-  /* If we're not doing DHCPv6, and there are not v6 leases, don't add the DUID to the database */
-  if (!daemon->duid && daemon->dhcp6)
-    {
-      file_dirty = 1;
-      make_duid(now);
-    }
-#endif
-
 }
 
 void lease_update_from_configs(void)
@@ -381,11 +371,18 @@ static int find_interface_v6(struct in6_addr *local,  int prefix,
    we do DHCP transactions, but information about directly-connected subnets
    is useful from scrips and necessary for determining SLAAC addresses from
    start-time. */
-void lease_find_interfaces(void)
+void lease_find_interfaces(time_t now)
 {
   iface_enumerate(AF_INET, NULL, find_interface_v4);
 #ifdef HAVE_DHCP6
   iface_enumerate(AF_INET6, NULL, find_interface_v6);
+
+  /* If we're not doing DHCPv6, and there are not v6 leases, don't add the DUID to the database */
+  if (!daemon->duid && daemon->dhcp6)
+    {
+      file_dirty = 1;
+      make_duid(now);
+    }
 #endif
 }
 

src/option.c

@@ -115,6 +115,7 @@ struct myoption {
 #define LOPT_FQDN      304
 #define LOPT_LUASCRIPT 305
 #define LOPT_RA        306
+#define LOPT_DUID      307
 
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
@@ -235,6 +236,7 @@ static const struct myoption opts[] =
     { "dhcp-client-update", 0, 0, LOPT_FQDN },
     { "dhcp-luascript", 1, 0, LOPT_LUASCRIPT },
     { "enable-ra", 0, 0, LOPT_RA },
+    { "dhcp-duid", 1, 0, LOPT_DUID },
     { NULL, 0, 0, 0 }
   };
 
@@ -362,6 +364,7 @@ static struct {
   { LOPT_CONNTRACK, OPT_CONNTRACK, NULL, gettext_noop("Copy connection-track mark from queries to upstream connections."), NULL },
   { LOPT_FQDN, OPT_FQDN_UPDATE, NULL, gettext_noop("Allow DHCP clients to do their own DDNS updates."), NULL },
   { LOPT_RA, OPT_RA, NULL, gettext_noop("Send router-advertisements for interfaces doing DHCPv6"), NULL },
+  { LOPT_DUID, ARG_ONE, "<enterprise>,<duid>", gettext_noop("Specify DUID_EN-type DHCPv6 server DUID"), NULL },
   { 0, 0, NULL, NULL, NULL }
 }; 
 
@@ -3047,6 +3050,19 @@ static char *one_opt(int option, char *arg, char *gen_prob, int command_line)
       break;
 #endif
       
+#ifdef HAVE_DHCP6
+    case LOPT_DUID: /* --dhcp-duid */
+      if (!(comma = split(arg)) || !atoi_check(arg, (int *)&daemon->duid_enterprise))
+	problem = _("bad DUID");
+      else
+	{
+	  daemon->duid_config_len = parse_hex(comma,(unsigned char *)comma, strlen(comma), NULL, NULL);
+	  daemon->duid_config = opt_malloc(daemon->duid_config_len);
+	  memcpy(daemon->duid_config, comma, daemon->duid_config_len);
+	}
+      break;
+#endif
+
     case 'V':  /* --alias */
       {
 	char *dash, *a[3] = { NULL, NULL, NULL };