Add --dhcp-name-match

CHANGELOG

@@ -49,6 +49,8 @@ version 2.80
 	DNS configuration which confused systemd-resolvd. Thanks to
 	Steve Dodd for characterising the problem.
 
+	Add --dhcp-name-match config option. 
+
 
 version 2.79
 	Fix parsing of CNAME arguments, which are confused by extra spaces.

man/dnsmasq.8

@@ -1329,6 +1329,9 @@ The special form with vi-encap:<enterprise number> matches against
 vendor-identifying vendor classes for the specified enterprise. Please
 see RFC 3925 for more details of these rare and interesting beasts.
 .TP
+.B --dhcp-name-match=set:<tag>,<name>[*]
+Set the tag if the given name is supplied by a dhcp client. There may be a single trailing wildcard *, which has the usual meaning. Combined with dhcp-ignore or dhcp-ignore-names this gives the ability to ignore certain clients by name, or disallow certain hostnames from being claimed by a client.
+.TP
 .B --tag-if=set:<tag>[,set:<tag>[,tag:<tag>[,tag:<tag>]]]
 Perform boolean operations on tags. Any tag appearing as set:<tag> is set if
 all the tags which appear as tag:<tag> are set, (or unset when tag:!<tag> is used)

src/dnsmasq.h

@@ -822,6 +822,13 @@ struct dhcp_boot {
   struct dhcp_boot *next;
 };
 
+struct dhcp_match_name {
+  char *name;
+  int wildcard;
+  struct dhcp_netid *netid;
+  struct dhcp_match_name *next;
+};
+
 struct pxe_service {
   unsigned short CSA, type; 
   char *menu, *basename, *sname;
@@ -1014,6 +1021,7 @@ extern struct daemon {
   struct ra_interface *ra_interfaces;
   struct dhcp_config *dhcp_conf;
   struct dhcp_opt *dhcp_opts, *dhcp_match, *dhcp_opts6, *dhcp_match6;
+  struct dhcp_match_name *dhcp_name_match;
   struct dhcp_vendor *dhcp_vendors;
   struct dhcp_mac *dhcp_macs;
   struct dhcp_boot *boot_config;

src/option.c

@@ -164,6 +164,7 @@ struct myoption {
 #define LOPT_DUMPFILE      352
 #define LOPT_DUMPMASK      353
 #define LOPT_UBUS          354
+#define LOPT_NAME_MATCH    355
  
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
@@ -274,6 +275,7 @@ static const struct myoption opts[] =
     { "rebind-domain-ok", 1, 0, LOPT_NO_REBIND },
     { "all-servers", 0, 0, LOPT_NOLAST }, 
     { "dhcp-match", 1, 0, LOPT_MATCH },
+    { "dhcp-name-match", 1, 0, LOPT_NAME_MATCH },
     { "dhcp-broadcast", 2, 0, LOPT_BROADCAST },
     { "neg-ttl", 1, 0, LOPT_NEGTTL },
     { "max-ttl", 1, 0, LOPT_MAXTTL },
@@ -456,6 +458,7 @@ static struct {
   { LOPT_NO_REBIND, ARG_DUP, "/<domain>/", gettext_noop("Inhibit DNS-rebind protection on this domain."), NULL },
   { LOPT_NOLAST, OPT_ALL_SERVERS, NULL, gettext_noop("Always perform DNS queries to all servers."), NULL },
   { LOPT_MATCH, ARG_DUP, "set:<tag>,<optspec>", gettext_noop("Set tag if client includes matching option in request."), NULL },
+  { LOPT_NAME_MATCH, ARG_DUP, "set:<tag>,<string>[*]", gettext_noop("Set tag if client provides given name."), NULL },
   { LOPT_ALTPORT, ARG_ONE, "[=<ports>]", gettext_noop("Use alternative ports for DHCP."), NULL },
   { LOPT_NAPTR, ARG_DUP, "<name>,<naptr>", gettext_noop("Specify NAPTR DNS record."), NULL },
   { LOPT_MINPORT, ARG_ONE, "<port>", gettext_noop("Specify lowest port available for DNS query transmission."), NULL },
@@ -3287,6 +3290,32 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			    (option == LOPT_MATCH ? DHOPT_MATCH :
 			     (option == LOPT_OPTS ? DHOPT_BANK : 0)));
 
+    case LOPT_NAME_MATCH: /* --dhcp-name-match */
+      {
+	struct dhcp_match_name *new = opt_malloc(sizeof(struct dhcp_match_name));
+	struct dhcp_netid *id = opt_malloc(sizeof(struct dhcp_netid));
+	ssize_t len;
+	
+	if (!(comma = split(arg)) || (len = strlen(comma)) == 0)
+	  ret_err(gen_err);
+
+	new->wildcard = 0;
+	new->netid = id;
+	id->net = opt_string_alloc(set_prefix(arg));
+
+	if (comma[len-1] == '*')
+	  {
+	    comma[len-1] = 0;
+	    new->wildcard = 1;
+	  }
+	new->name = opt_string_alloc(comma);
+
+	new->next = daemon->dhcp_name_match;
+	daemon->dhcp_name_match = new;
+
+	break;
+      }
+      
     case 'M': /* --dhcp-boot */
       {
 	struct dhcp_netid *id = NULL;

src/rfc2131.c

@@ -700,9 +700,40 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 	client_hostname = daemon->dhcp_buff;
     }
 
-  if (client_hostname && option_bool(OPT_LOG_OPTS))
+  if (client_hostname)
+    {
+      struct dhcp_match_name *m;
+      size_t nl = strlen(client_hostname); 
+      
+      if (option_bool(OPT_LOG_OPTS))
 	my_syslog(MS_DHCP | LOG_INFO, _("%u client provides name: %s"), ntohl(mess->xid), client_hostname);
 
+
+      for (m = daemon->dhcp_name_match; m; m = m->next)
+	{
+	  size_t ml = strlen(m->name);
+	  char save = 0;
+	  
+	  if (nl < ml)
+	    continue;
+	  if (nl > ml)
+	    {
+	      save = client_hostname[ml];
+	      client_hostname[ml] = 0;
+	    }
+
+	  if (hostname_isequal(client_hostname, m->name) &&
+	      (save == 0 || m->wildcard))
+	    {
+	      m->netid->next = netid;
+	      netid = m->netid;
+	    }
+
+	  if (save != 0)
+	    client_hostname[ml] = save;
+	}
+    }
+  
   if (have_config(config, CONFIG_NAME))
     {
       hostname = config->hostname;