pcapng: expand the plugin option handlers to support writing options.

The options get unmarshalled (deserialized) when you read them; they
need to get marshalled (serialized) when you write them.  This requires
an option handler to have more than one function.

While we're at it, in the declarations for function types for *block*
reader and writer plugins, add names to the prototype function
arguments, to make it a bit clearer what those arguments are.

1 files changed, 46 insertions, 16 deletions

diff --git a/wiretap/pcapng.c b/wiretap/pcapng.c
index a107a06767..c71c1e7fc3 100644
--- a/wiretap/pcapng.c
+++ b/wiretap/pcapng.c
@@ -344,18 +344,42 @@ register_pcapng_block_type_handler(guint block_type, block_reader reader,
  * Tables for plugins to handle particular options for particular block
  * types.
  *
- * An option has a handler routine, which is passed an indication of
- * whether this section of the file is byte-swapped, the length of the
- * option, the data of the option, a pointer to an error code, and a
- * pointer to a pointer variable for an error string.
+ * An option has three handler routines:
  *
- * It checks whether the length and option are valid, and, if they aren't,
- * returns FALSE, setting the error code to the appropriate error (normally
- * WTAP_ERR_BAD_FILE) and the error string to an appropriate string
- * indicating the problem.
+ *   An option parser, used when reading an option from a file:
  *
- * Otherwise, if this section of the file is byte-swapped, it byte-swaps
- * multi-byte numerical values, so that it's in the host byte order.
+ *     The option parser is passed an indication of whether this section
+ *     of the file is byte-swapped, the length of the option, the data of
+ *     the option, a pointer to an error code, and a pointer to a pointer
+ *     variable for an error string.
+ *
+ *     It checks whether the length and option are valid, and, if they
+ *     aren't, returns FALSE, setting the error code to the appropriate
+ *     error (normally WTAP_ERR_BAD_FILE) and the error string to an
+ *     appropriate string indicating the problem.
+ *
+ *     Otherwise, if this section of the file is byte-swapped, it byte-swaps
+ *     multi-byte numerical values, so that it's in the host byte order.
+ *
+ *   An option sizer, used when writing an option to a file:
+ *
+ *     The option sizer is passed the option identifier for the option
+ *     and a wtap_optval_t * that points to the data for the option.
+ *
+ *     It calculates how many bytes the option's data requires, not
+ *     including any padding bytes, and returns that value.
+ *
+ *   An option writer, used when writing an option to a file:
+ *
+ *     The option writer is passed a wtap_dumper * to which the
+ *     option data should be written, the option identifier for
+ *     the option, a wtap_optval_t * that points to the data for
+ *     the option, and an int * into which an error code should
+ *     be stored if an error occurs when writing the option.
+ *
+ *     It returns a gboolean value of TRUE if the attempt to
+ *     write the option succeeds and FALSE if the attempt to
+ *     write the option gets an error.
  */
 
 /*
@@ -376,7 +400,9 @@ register_pcapng_block_type_handler(guint block_type, block_reader reader,
 #define NUM_BT_INDICES      7
 
 typedef struct {
-    option_handler_fn hfunc;
+    option_parser parser;
+    option_sizer sizer;
+    option_writer writer;
 } option_handler;
 
 static GHashTable *option_handlers[NUM_BT_INDICES];
@@ -436,7 +462,9 @@ get_block_type_index(guint block_type, guint *bt_index)
 
 void
 register_pcapng_option_handler(guint block_type, guint option_code,
-                               option_handler_fn hfunc)
+                               option_parser parser,
+                               option_sizer sizer,
+                               option_writer writer)
 {
     guint bt_index;
     option_handler *handler;
@@ -456,9 +484,11 @@ register_pcapng_option_handler(guint block_type, guint option_code,
                                                           NULL, g_free);
     }
     handler = g_new(option_handler, 1);
-    handler->hfunc = hfunc;
+    handler->parser = parser;
+    handler->sizer = sizer;
+    handler->writer = writer;
     g_hash_table_insert(option_handlers[bt_index],
-                              GUINT_TO_POINTER(option_code), handler);
+                        GUINT_TO_POINTER(option_code), handler);
 }
 #endif /* HAVE_PLUGINS */
 
@@ -623,8 +653,8 @@ pcap_process_unhandled_option(wtapng_block_t *wblock,
         (handler = (option_handler *)g_hash_table_lookup(option_handlers[bt_index],
                                                          GUINT_TO_POINTER((guint)ohp->option_code))) != NULL) {
         /* Yes - call the handler. */
-        if (!handler->hfunc(wblock->block, section_info->byte_swapped,
-                            ohp->option_length, option_content, err, err_info))
+        if (!handler->parser(wblock->block, section_info->byte_swapped,
+                             ohp->option_length, option_content, err, err_info))
             /* XXX - free anything? */
             return FALSE;
     }