udhcpd: remove five more options which do not make sense or not supported

requestip, vendorclass, clientid are client-side variables,
          they do not make sense as udhcpd opts
dhcptype  is the packet type (not interesting, it's always 5)
userclass needs parser support in order to work

function                                             old     new   delta
dhcp_options                                          68      66      -2
read_opt                                             865     859      -6
dhcp_option_strings                                  253     203     -50
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-58)             Total: -58 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

5 files changed, 58 insertions, 45 deletions

diff --git a/examples/udhcp/udhcpd.conf b/examples/udhcp/udhcpd.conf
index 1e05435d4..7fc37ab00 100644
--- a/examples/udhcp/udhcpd.conf
+++ b/examples/udhcp/udhcpd.conf
@@ -63,27 +63,35 @@ option	domain	local
 option  lease   864000          # 10 days of seconds
 
 # Currently supported options (for more info, see options.c):
-#opt subnet
-#opt timezone
-#opt router
-#opt timesrv
-#opt namesrv - obsolete, disabled
-#opt dns
-#opt logsrv
-#opt cookiesrv - rarely (never?) used, disabled
-#opt lprsrv
-#opt bootsize
-#opt domain
-#opt swapsrv
-#opt rootpath
-#opt ipttl
-#opt mtu
-#opt broadcast
-#opt wins
-#opt lease
-#opt ntpsrv
-#opt tftp
-#opt bootfile
+#opt lease      NUM
+#opt subnet     IP
+#opt broadcast  IP
+#opt router     IP_LIST
+#opt ipttl      NUM
+#opt mtu        NUM
+#opt hostname   STRING      - client's hostname
+#opt domain     STRING      - client's domain name
+#opt search     STRING_LIST - search domains
+#opt nisdomain  STRING
+#opt timezone   NUM
+#opt tftp       STRING - TFTP server name
+#opt bootfile   STRING - file (kernel image) to load for booting
+#opt bootsize   NUM    - size of that file
+#opt rootpath   STRING - (NFS) path to mount as root fs
+#opt wpad       STRING
+#opt serverid   IP     - by default, server's IP
+#opt message    STRING - error message (udhcpd sends it on success too)
+# Options specifying server(s)
+#opt dns        IP_LIST
+#opt wins       IP_LIST
+#opt nissrv     IP_LIST
+#opt namesrv    IP_LIST - obsolete, disabled
+#opt logsrv     IP_LIST
+#opt cookiesrv  IP_LIST - rarely (never?) used, disabled
+#opt lprsrv     IP_LIST
+#opt swapsrv    IP
+#opt timesrv    IP_LIST
+#opt ntpsrv     IP_LIST
 
 # Static leases map
 #static_lease 00:60:08:11:CE:4E 192.168.0.54
diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c
index 1b2cc96f4..40cfe9fd2 100644
--- a/networking/udhcp/files.c
+++ b/networking/udhcp/files.c
@@ -201,9 +201,8 @@ static int FAST_FUNC read_opt(const char *const_line, void *arg)
 #if ENABLE_FEATURE_UDHCP_RFC3397
                 case OPTION_STR1035:
 #endif
-                        length = strlen(val);
+                        length = strnlen(val, 254);
                         if (length > 0) {
-                                if (length > 254) length = 254;
                                 opt = val;
                                 retval = 1;
                         }
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index 6ab5708e6..c2a230527 100644
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -11,7 +11,9 @@
 #include "options.h"
 
 
-/* Supported options are easily added here. See RFC2132 */
+/* Supported options are easily added here.
+ * See RFC2132 for more options.
+ */
 const struct dhcp_option dhcp_options[] = {
         /* flags                                    code */
         { OPTION_IP                   | OPTION_REQ, 0x01 }, /* DHCP_SUBNET        */
@@ -25,7 +27,7 @@ const struct dhcp_option dhcp_options[] = {
         { OPTION_IP | OPTION_LIST                 , 0x09 }, /* DHCP_LPR_SERVER    */
         { OPTION_STRING               | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME     */
         { OPTION_U16                              , 0x0d }, /* DHCP_BOOT_SIZE     */
-        { OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME   */
+        { OPTION_STRING               | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME   */
         { OPTION_IP                               , 0x10 }, /* DHCP_SWAP_SERVER   */
         { OPTION_STRING                           , 0x11 }, /* DHCP_ROOT_PATH     */
         { OPTION_U8                               , 0x17 }, /* DHCP_IP_TTL        */
@@ -35,16 +37,13 @@ const struct dhcp_option dhcp_options[] = {
         { OPTION_IP | OPTION_LIST                 , 0x29 }, /* nissrv             */
         { OPTION_IP | OPTION_LIST     | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER    */
         { OPTION_IP | OPTION_LIST                 , 0x2c }, /* DHCP_WINS_SERVER   */
-        { OPTION_IP                               , 0x32 }, /* DHCP_REQUESTED_IP  */
         { OPTION_U32                              , 0x33 }, /* DHCP_LEASE_TIME    */
-        { OPTION_U8                               , 0x35 }, /* DHCP_MESSAGE_TYPE  */
         { OPTION_IP                               , 0x36 }, /* DHCP_SERVER_ID     */
         { OPTION_STRING                           , 0x38 }, /* DHCP_MESSAGE       */
-        { OPTION_STRING                           , 0x3C }, /* DHCP_VENDOR        */
-        { OPTION_STRING                           , 0x3D }, /* DHCP_CLIENT_ID     */
         { OPTION_STRING                           , 0x42 }, /* tftp               */
         { OPTION_STRING                           , 0x43 }, /* bootfile           */
-        { OPTION_STRING                           , 0x4D }, /* userclass          */
+//TODO: not a string, but a set of LASCII strings:
+//      { OPTION_STRING                           , 0x4D }, /* userclass          */
 #if ENABLE_FEATURE_UDHCP_RFC3397
         { OPTION_STR1035 | OPTION_LIST            , 0x77 }, /* search             */
 #endif
@@ -54,14 +53,23 @@ const struct dhcp_option dhcp_options[] = {
 
         /* Options below have no match in dhcp_option_strings[],
          * are not passed to dhcpc scripts, and cannot be specified
-         * with "option XXX YYY" syntax in dhcpd config file. */
+         * with "option XXX YYY" syntax in dhcpd config file.
+         * These entries are only used internally by udhcp[cd]
+         * to correctly encode options into packets.
+         */
 
+        { OPTION_IP                               , 0x32 }, /* DHCP_REQUESTED_IP  */
+        { OPTION_U8                               , 0x35 }, /* DHCP_MESSAGE_TYPE  */
         { OPTION_U16                              , 0x39 }, /* DHCP_MAX_SIZE      */
+        { OPTION_STRING                           , 0x3C }, /* DHCP_VENDOR        */
+        { OPTION_STRING                           , 0x3D }, /* DHCP_CLIENT_ID     */
         { 0, 0 } /* zeroed terminating entry */
 };
 
 /* Used for converting options from incoming packets to env variables
- * for udhcpc stript */
+ * for udhcpc stript, and for setting options for udhcpd via
+ * "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file.
+ */
 /* Must match dhcp_options[] order */
 const char dhcp_option_strings[] ALIGN1 =
         "subnet" "\0"      /* DHCP_SUBNET         */
@@ -85,19 +93,17 @@ const char dhcp_option_strings[] ALIGN1 =
         "nissrv" "\0"      /*                     */
         "ntpsrv" "\0"      /* DHCP_NTP_SERVER     */
         "wins" "\0"        /* DHCP_WINS_SERVER    */
-        "requestip" "\0"   /* DHCP_REQUESTED_IP   */
         "lease" "\0"       /* DHCP_LEASE_TIME     */
-        "dhcptype" "\0"    /*                     */
         "serverid" "\0"    /* DHCP_SERVER_ID      */
         "message" "\0"     /* DHCP_MESSAGE        */
-        "vendorclass" "\0" /* DHCP_VENDOR         */
-        "clientid" "\0"    /* DHCP_CLIENT_ID      */
         "tftp" "\0"
         "bootfile" "\0"
-        "userclass" "\0"
+//      "userclass" "\0"
 #if ENABLE_FEATURE_UDHCP_RFC3397
         "search" "\0"
 #endif
+// "staticroutes" is only used to set udhcpc environment, it doesn't work
+// in udhcpd.conf since OPTION_STATIC_ROUTES is not handled yet:
         "staticroutes" "\0" /* DHCP_STATIC_ROUTES  */
         /* MSIE's "Web Proxy Autodiscovery Protocol" support */
         "wpad" "\0"
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 8f6ab0f15..2d9c15f8a 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -41,10 +41,10 @@ enum {
 #define DHCP_TIME_OFFSET        0x02
 #define DHCP_ROUTER             0x03
 #define DHCP_TIME_SERVER        0x04
-//#define DHCP_NAME_SERVER      0x05 /* _really_ ancient */
+//#define DHCP_NAME_SERVER      0x05 /* _really_ ancient kind of NS */
 #define DHCP_DNS_SERVER         0x06
 #define DHCP_LOG_SERVER         0x07
-//#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" */
+//#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" server */
 #define DHCP_LPR_SERVER         0x09
 #define DHCP_HOST_NAME          0x0c
 #define DHCP_BOOT_SIZE          0x0d
@@ -56,18 +56,18 @@ enum {
 #define DHCP_BROADCAST          0x1c
 #define DHCP_NTP_SERVER         0x2a
 #define DHCP_WINS_SERVER        0x2c
-#define DHCP_REQUESTED_IP       0x32
+#define DHCP_REQUESTED_IP       0x32 /* sent by client if specific IP is wanted */
 #define DHCP_LEASE_TIME         0x33
 #define DHCP_OPTION_OVERLOAD    0x34
 #define DHCP_MESSAGE_TYPE       0x35
-#define DHCP_SERVER_ID          0x36
+#define DHCP_SERVER_ID          0x36 /* by default server's IP */
 #define DHCP_PARAM_REQ          0x37
-#define DHCP_MESSAGE            0x38
+#define DHCP_MESSAGE            0x38 /* error message when sending NAK etc */
 #define DHCP_MAX_SIZE           0x39
 //#define DHCP_T1               0x3a
 //#define DHCP_T2               0x3b
-#define DHCP_VENDOR             0x3c
-#define DHCP_CLIENT_ID          0x3d
+#define DHCP_VENDOR             0x3c /* client's vendor */
+#define DHCP_CLIENT_ID          0x3d /* by default client's MAC addr */
 #define DHCP_FQDN               0x51
 #define DHCP_STATIC_ROUTES      0x79
 #define DHCP_END                0xFF
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index dc658ada8..321b015e0 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -177,7 +177,7 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_
 }
 
 
-/* put all the parameters into an environment */
+/* put all the parameters into the environment */
 static char **fill_envp(struct dhcp_packet *packet)
 {
         int num_options = 0;