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#include "wire/tlvstream.h"
#include <assert.h>
#include <wire/wire.h>
#ifndef SUPERVERBOSE
#define SUPERVERBOSE(...)
#endif
static const struct tlv_record_type *
find_record_type(u64 type,
const struct tlv_record_type types[],
size_t num_types)
{
for (size_t i = 0; i < num_types; i++)
if (types[i].type == type)
return types + i;
return NULL;
}
/* Pull all tlvs from a stream. Return false and calls fromwire_fail() on
* error. */
bool fromwire_tlvs(const u8 **cursor, size_t *max,
const struct tlv_record_type types[],
size_t num_types,
void *record)
{
/* prev_type points to prev_type_store after first iter. */
u64 prev_type_store, *prev_type = NULL;
/* BOLT #1:
*
* The receiving node:
* - if zero bytes remain before parsing a `type`:
* - MUST stop parsing the `tlv_stream`.
*/
while (*max > 0) {
u64 type, length;
const struct tlv_record_type *rtype;
/* BOLT #1:
*
* A `varint` is a variable-length, unsigned integer encoding
* using the [BigSize](#appendix-a-bigsize-test-vectors)
* format
*/
type = fromwire_bigsize(cursor, max);
/* BOLT #1:
* - if a `type` or `length` is not minimally encoded:
* - MUST fail to parse the `tlv_stream`.
*/
if (!*cursor) {
SUPERVERBOSE("type");
goto fail;
}
length = fromwire_bigsize(cursor, max);
/* BOLT #1:
* - if a `type` or `length` is not minimally encoded:
* - MUST fail to parse the `tlv_stream`.
*/
if (!*cursor) {
SUPERVERBOSE("length");
goto fail;
}
/* BOLT #1:
* - if `length` exceeds the number of bytes remaining in the
* message:
* - MUST fail to parse the `tlv_stream`.
*/
if (length > *max) {
SUPERVERBOSE("value");
goto fail;
}
/* BOLT #1:
* - if decoded `type`s are not monotonically-increasing:
* - MUST fail to parse the `tlv_stream`.
*/
if (prev_type && type <= *prev_type) {
if (type == *prev_type)
SUPERVERBOSE("duplicate tlv type");
else
SUPERVERBOSE("invalid ordering");
goto fail;
}
/* BOLT #1:
* - if `type` is known:
* - MUST decode the next `length` bytes using the known
* encoding for `type`.
*/
rtype = find_record_type(type, types, num_types);
if (rtype) {
/* Length of message can't exceed 16 bits anyway. */
size_t tlvlen = length;
rtype->fromwire(cursor, &tlvlen, record);
if (!*cursor)
goto fail;
/* BOLT #1:
* - if `length` is not exactly equal to that required
* for the known encoding for `type`:
* - MUST fail to parse the `tlv_stream`.
*/
if (tlvlen != 0) {
SUPERVERBOSE("greater than encoding length");
goto fail;
}
/* We've read bytes in ->fromwire, so update max */
*max -= length;
} else {
/* BOLT #1:
* - otherwise, if `type` is unknown:
* - if `type` is even:
* - MUST fail to parse the `tlv_stream`.
* - otherwise, if `type` is odd:
* - MUST discard the next `length` bytes.
*/
if (type & 1)
fromwire(cursor, max, NULL, length);
else {
SUPERVERBOSE("unknown even");
goto fail;
}
}
prev_type = &prev_type_store;
*prev_type = type;
}
return true;
fail:
fromwire_fail(cursor, max);
return false;
}
/* Append a stream of tlvs. */
void towire_tlvs(u8 **pptr,
const struct tlv_record_type types[],
size_t num_types,
const void *record)
{
if (!record)
return;
for (size_t i = 0; i < num_types; i++) {
u8 *val;
if (i != 0)
assert(types[i].type > types[i-1].type);
val = types[i].towire(NULL, record);
if (!val)
continue;
/* BOLT #1:
*
* The sending node:
...
* - MUST minimally encode `type` and `length`.
*/
towire_bigsize(pptr, types[i].type);
towire_bigsize(pptr, tal_bytelen(val));
towire(pptr, val, tal_bytelen(val));
tal_free(val);
}
}