[ipv6] Allow settings to comprise arbitrary subsets of NDP options

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/net/ndp.c b/src/net/ndp.c
index fb6f323199cb41cf4c63dcde393574783a44e7dc..0876efd94efec609688f1d200d6999cab9432e74 100644 (file)
--- a/src/net/ndp.c
+++ b/src/net/ndp.c
@@ -636,7 +636,7 @@ struct ndp_settings {
        /** Length of NDP options */
        size_t len;
        /** NDP options */
-       union ndp_option option[0];
+       union ndp_option options[0];
 };
 
 /** NDP settings scope */
@@ -647,9 +647,11 @@ static const struct settings_scope ndp_settings_scope;
  *
  * @v type             NDP option type
  * @v offset           Starting offset of data
+ * @v len              Length of data (or 0 to use all remaining data)
  * @ret tag            NDP tag
  */
-#define NDP_TAG( type, offset )        ( ( (offset) << 8 ) | (type) )
+#define NDP_TAG( type, offset, len ) \
+       ( ( (len) << 16 ) | ( (offset) << 8 ) | (type) )
 
 /**
  * Extract NDP tag type
@@ -657,7 +659,7 @@ static const struct settings_scope ndp_settings_scope;
  * @v tag              NDP tag
  * @ret type           NDP option type
  */
-#define NDP_TAG_TYPE( tag ) ( (tag) & 0xff )
+#define NDP_TAG_TYPE( tag ) ( ( (tag) >> 0 ) & 0xff )
 
 /**
  * Extract NDP tag offset
@@ -665,7 +667,23 @@ static const struct settings_scope ndp_settings_scope;
  * @v tag              NDP tag
  * @ret offset         Starting offset of data
  */
-#define NDP_TAG_OFFSET( tag ) ( (tag) >> 8 )
+#define NDP_TAG_OFFSET( tag ) ( ( (tag) >> 8 ) & 0xff )
+
+/**
+ * Extract NDP tag length
+ *
+ * @v tag              NDP tag
+ * @ret len            Length of data (or 0 to use all remaining data)
+ */
+#define NDP_TAG_LEN( tag ) ( ( (tag) >> 16 ) & 0xff )
+
+/**
+ * Extract NDP tag instance
+ *
+ * @v tag              NDP tag
+ * @ret instance       Instance
+ */
+#define NDP_TAG_INSTANCE( tag ) ( ( (tag) >> 24 ) & 0xff )
 
 /**
  * Check applicability of NDP setting
@@ -698,44 +716,58 @@ static int ndp_fetch ( struct settings *settings,
                container_of ( settings->parent, struct net_device,
                               settings.settings );
        union ndp_option *option;
-       unsigned int type = NDP_TAG_TYPE ( setting->tag );
-       unsigned int offset = NDP_TAG_OFFSET ( setting->tag );
-       size_t remaining;
+       unsigned int tag_type;
+       unsigned int tag_offset;
+       unsigned int tag_len;
+       unsigned int tag_instance;
+       size_t offset;
        size_t option_len;
-       size_t payload_len;
+       void *option_data;
+
+       /* Parse setting tag */
+       tag_type = NDP_TAG_TYPE ( setting->tag );
+       tag_offset = NDP_TAG_OFFSET ( setting->tag );
+       tag_len = NDP_TAG_LEN ( setting->tag );
+       tag_instance = NDP_TAG_INSTANCE ( setting->tag );
 
        /* Scan through NDP options for requested type.  We can assume
         * that the options are well-formed, otherwise they would have
         * been rejected prior to being stored.
         */
-       option = ndpset->option;
-       remaining = ndpset->len;
-       while ( remaining ) {
+       for ( offset = 0 ; offset < ndpset->len ; offset += option_len ) {
 
                /* Calculate option length */
+               option = ( ( ( void * ) ndpset->options ) + offset );
                option_len = ( option->header.blocks * NDP_OPTION_BLKSZ );
 
-               /* If this is the requested option, return it */
-               if ( option->header.type == type ) {
-
-                       /* Sanity check */
-                       if ( offset > option_len ) {
-                               DBGC ( netdev, "NDP %s option %d too short\n",
-                                      netdev->name, type );
-                               return -EINVAL;
-                       }
-                       payload_len = ( option_len - offset );
-
-                       /* Copy data to output buffer */
-                       if ( len > payload_len )
-                               len = payload_len;
-                       memcpy ( data, ( ( ( void * ) option ) + offset ), len);
-                       return payload_len;
+               /* Skip options that do not match this tag */
+               if ( option->header.type != tag_type )
+                       continue;
+
+               /* Skip previous instances of this option */
+               if ( tag_instance-- != 0 )
+                       continue;
+
+               /* Sanity check */
+               if ( ( tag_offset + tag_len ) > option_len ) {
+                       DBGC ( netdev, "NDP %s option %d too short\n",
+                              netdev->name, tag_type );
+                       return -EINVAL;
                }
+               if ( ! tag_len )
+                       tag_len = ( option_len - tag_offset );
+               option_data = ( ( ( void * ) option ) + tag_offset );
 
-               /* Move to next option */
-               option = ( ( ( void * ) option ) + option_len );
-               remaining -= option_len;
+               /* Copy data to output buffer */
+               if ( len > tag_len )
+                       len = tag_len;
+               memcpy ( data, option_data, len );
+
+               /* Default to hex if no type is specified */
+               if ( ! setting->type )
+                       setting->type = &setting_type_hex;
+
+               return tag_len;
        }
 
        return -ENOENT;
@@ -751,12 +783,12 @@ static struct settings_operations ndp_settings_operations = {
  * Register NDP settings
  *
  * @v netdev           Network device
- * @v option           NDP options
+ * @v options          NDP options
  * @v len              Length of options
  * @ret rc             Return status code
  */
 static int ndp_register_settings ( struct net_device *netdev,
-                                  union ndp_option *option, size_t len ) {
+                                  union ndp_option *options, size_t len ) {
        struct settings *parent = netdev_settings ( netdev );
        struct ndp_settings *ndpset;
        int rc;
@@ -771,7 +803,7 @@ static int ndp_register_settings ( struct net_device *netdev,
        settings_init ( &ndpset->settings, &ndp_settings_operations,
                        &ndpset->refcnt, &ndp_settings_scope );
        ndpset->len = len;
-       memcpy ( ndpset->option, option, len );
+       memcpy ( ndpset->options, options, len );
 
        /* Register settings */
        if ( ( rc = register_settings ( &ndpset->settings, parent,
@@ -789,7 +821,7 @@ const struct setting ndp_dns6_setting __setting ( SETTING_IP6_EXTRA, dns6 ) = {
        .name = "dns6",
        .description = "DNS server",
        .tag = NDP_TAG ( NDP_OPT_RDNSS,
-                        offsetof ( struct ndp_rdnss_option, addresses ) ),
+                        offsetof ( struct ndp_rdnss_option, addresses ), 0 ),
        .type = &setting_type_ipv6,
        .scope = &ndp_settings_scope,
 };
@@ -799,7 +831,7 @@ const struct setting ndp_dnssl_setting __setting ( SETTING_IP_EXTRA, dnssl ) = {
        .name = "dnssl",
        .description = "DNS search list",
        .tag = NDP_TAG ( NDP_OPT_DNSSL,
-                        offsetof ( struct ndp_dnssl_option, names ) ),
+                        offsetof ( struct ndp_dnssl_option, names ), 0 ),
        .type = &setting_type_dnssl,
        .scope = &ndp_settings_scope,
 };