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common/tlvstream: put TLV checking back in the generic function.

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Callers were supposed to call "tlv_fields_valid" after fromwire_tlv,
but few did.  Make this the default, and call the underlying function
directly where we want to be more flexible (one place).

This loses the ability to allow misordered fields, or to pass through
*any* even fields.  We restore that for special cases in the next
patch.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2022-03-23 13:14:36 +10:30
parent a770f51d0e
commit 83ee68ab06
12 changed files with 165 additions and 155 deletions
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8
common/blindedpath.c
View file

@ -188,7 +188,6 @@ static struct tlv_encrypted_data_tlv *decrypt_encmsg(const tal_t *ctx,
const struct secret *ss,
const u8 *enctlv)
{
struct tlv_encrypted_data_tlv *encmsg;
const u8 *cursor = decrypt_encmsg_raw(tmpctx, blinding, ss, enctlv);
size_t maxlen = tal_bytelen(cursor);
@ -197,12 +196,7 @@ static struct tlv_encrypted_data_tlv *decrypt_encmsg(const tal_t *ctx,
* - if the `enctlv` is not a valid TLV...
* - MUST drop the message.
*/
encmsg = fromwire_tlv_encrypted_data_tlv(ctx, &cursor, &maxlen);
if (!encmsg
|| !tlv_fields_valid(encmsg->fields, NULL, NULL))
return tal_free(encmsg);
return encmsg;
return fromwire_tlv_encrypted_data_tlv(ctx, &cursor, &maxlen);
}
bool decrypt_enctlv(const struct pubkey *blinding,

33
common/onion.c
View file

@ -209,22 +209,21 @@ struct onion_payload *onion_decode(const tal_t *ctx,
const u8 *cursor = rs->raw_payload;
size_t max = tal_bytelen(cursor), len;
struct tlv_tlv_payload *tlv;
size_t badfield;
if (!pull_payload_length(&cursor, &max, true, &len))
goto general_fail;
tlv = fromwire_tlv_tlv_payload(p, &cursor, &max);
if (!tlv) {
/* FIXME: Fill in correct thing here! */
goto general_fail;
if (!pull_payload_length(&cursor, &max, true, &len)) {
*failtlvtype = 0;
*failtlvpos = tal_bytelen(rs->raw_payload);
goto fail_no_tlv;
}
/* FIXME: This API makes it really hard to get the actual
* offset of field. */
if (!tlv_fields_valid(tlv->fields, accepted_extra_tlvs, &badfield)) {
*failtlvtype = tlv->fields[badfield].numtype;
goto field_bad;
/* We do this manually so we can accept extra types, and get
* error off and type. */
tlv = tlv_tlv_payload_new(p);
if (!fromwire_tlv(&cursor, &max, tlvs_tlv_tlv_payload,
TLVS_ARRAY_SIZE_tlv_tlv_payload,
tlv, &tlv->fields, accepted_extra_tlvs,
failtlvpos, failtlvtype)) {
goto fail;
}
/* BOLT #4:
@ -336,14 +335,10 @@ struct onion_payload *onion_decode(const tal_t *ctx,
field_bad:
*failtlvpos = tlv_field_offset(rs->raw_payload, tal_bytelen(rs->raw_payload),
*failtlvtype);
goto fail;
general_fail:
*failtlvtype = 0;
*failtlvpos = tal_bytelen(rs->raw_payload);
goto fail;
fail:
tal_free(tlv);
fail_no_tlv:
tal_free(p);
return NULL;
}

7
common/test/run-json.c
View file

@ -11,12 +11,9 @@
/* Generated stub for fromwire_tlv */
bool fromwire_tlv(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,
void *record UNNEEDED, struct tlv_field **fields UNNEEDED)
void *record UNNEEDED, struct tlv_field **fields UNNEEDED,
const u64 *extra_types UNNEEDED, size_t *err_off UNNEEDED, u64 *err_type UNNEEDED)
{ fprintf(stderr, "fromwire_tlv called!\n"); abort(); }
/* Generated stub for tlv_fields_valid */
bool tlv_fields_valid(const struct tlv_field *fields UNNEEDED, u64 *allow_extra UNNEEDED,
size_t *err_index UNNEEDED)
{ fprintf(stderr, "tlv_fields_valid called!\n"); abort(); }
/* Generated stub for towire_tlv */
void towire_tlv(u8 **pptr UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,

7
common/test/run-param.c
View file

@ -37,7 +37,8 @@ struct command_result *command_fail(struct command *cmd,
/* Generated stub for fromwire_tlv */
bool fromwire_tlv(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,
void *record UNNEEDED, struct tlv_field **fields UNNEEDED)
void *record UNNEEDED, struct tlv_field **fields UNNEEDED,
const u64 *extra_types UNNEEDED, size_t *err_off UNNEEDED, u64 *err_type UNNEEDED)
{ fprintf(stderr, "fromwire_tlv called!\n"); abort(); }
/* Generated stub for json_to_channel_id */
bool json_to_channel_id(const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
@ -76,10 +77,6 @@ int segwit_addr_decode(
const char* addr
)
{ fprintf(stderr, "segwit_addr_decode called!\n"); abort(); }
/* Generated stub for tlv_fields_valid */
bool tlv_fields_valid(const struct tlv_field *fields UNNEEDED, u64 *allow_extra UNNEEDED,
size_t *err_index UNNEEDED)
{ fprintf(stderr, "tlv_fields_valid called!\n"); abort(); }
/* Generated stub for towire_tlv */
void towire_tlv(u8 **pptr UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,

7
common/test/run-route-specific.c
View file

@ -31,15 +31,12 @@ bool fromwire_channel_id(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
/* Generated stub for fromwire_tlv */
bool fromwire_tlv(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,
void *record UNNEEDED, struct tlv_field **fields UNNEEDED)
void *record UNNEEDED, struct tlv_field **fields UNNEEDED,
const u64 *extra_types UNNEEDED, size_t *err_off UNNEEDED, u64 *err_type UNNEEDED)
{ fprintf(stderr, "fromwire_tlv called!\n"); abort(); }
/* Generated stub for fromwire_wireaddr */
bool fromwire_wireaddr(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct wireaddr *addr UNNEEDED)
{ fprintf(stderr, "fromwire_wireaddr called!\n"); abort(); }
/* Generated stub for tlv_fields_valid */
bool tlv_fields_valid(const struct tlv_field *fields UNNEEDED, u64 *allow_extra UNNEEDED,
size_t *err_index UNNEEDED)
{ fprintf(stderr, "tlv_fields_valid called!\n"); abort(); }
/* Generated stub for towire_bigsize */
void towire_bigsize(u8 **pptr UNNEEDED, const bigsize_t val UNNEEDED)
{ fprintf(stderr, "towire_bigsize called!\n"); abort(); }

7
common/test/run-route.c
View file

@ -24,15 +24,12 @@ bool fromwire_channel_id(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
/* Generated stub for fromwire_tlv */
bool fromwire_tlv(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,
void *record UNNEEDED, struct tlv_field **fields UNNEEDED)
void *record UNNEEDED, struct tlv_field **fields UNNEEDED,
const u64 *extra_types UNNEEDED, size_t *err_off UNNEEDED, u64 *err_type UNNEEDED)
{ fprintf(stderr, "fromwire_tlv called!\n"); abort(); }
/* Generated stub for fromwire_wireaddr */
bool fromwire_wireaddr(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct wireaddr *addr UNNEEDED)
{ fprintf(stderr, "fromwire_wireaddr called!\n"); abort(); }
/* Generated stub for tlv_fields_valid */
bool tlv_fields_valid(const struct tlv_field *fields UNNEEDED, u64 *allow_extra UNNEEDED,
size_t *err_index UNNEEDED)
{ fprintf(stderr, "tlv_fields_valid called!\n"); abort(); }
/* Generated stub for towire_bigsize */
void towire_bigsize(u8 **pptr UNNEEDED, const bigsize_t val UNNEEDED)
{ fprintf(stderr, "towire_bigsize called!\n"); abort(); }

7
common/test/run-sphinx.c
View file

@ -57,7 +57,8 @@ bigsize_t fromwire_bigsize(const u8 **cursor UNNEEDED, size_t *max UNNEEDED)
/* Generated stub for fromwire_tlv */
bool fromwire_tlv(const u8 **cursor UNNEEDED, size_t *max UNNEEDED,
const struct tlv_record_type *types UNNEEDED, size_t num_types UNNEEDED,
void *record UNNEEDED, struct tlv_field **fields UNNEEDED)
void *record UNNEEDED, struct tlv_field **fields UNNEEDED,
const u64 *extra_types UNNEEDED, size_t *err_off UNNEEDED, u64 *err_type UNNEEDED)
{ fprintf(stderr, "fromwire_tlv called!\n"); abort(); }
/* Generated stub for pubkey_from_node_id */
bool pubkey_from_node_id(struct pubkey *key UNNEEDED, const struct node_id *id UNNEEDED)
@ -65,10 +66,6 @@ bool pubkey_from_node_id(struct pubkey *key UNNEEDED, const struct node_id *id U
/* Generated stub for tlv_field_offset */
size_t tlv_field_offset(const u8 *tlvstream UNNEEDED, size_t tlvlen UNNEEDED, u64 fieldtype UNNEEDED)
{ fprintf(stderr, "tlv_field_offset called!\n"); abort(); }
/* Generated stub for tlv_fields_valid */
bool tlv_fields_valid(const struct tlv_field *fields UNNEEDED, u64 *allow_extra UNNEEDED,
size_t *err_index UNNEEDED)
{ fprintf(stderr, "tlv_fields_valid called!\n"); abort(); }
/* Generated stub for towire_amount_msat */
void towire_amount_msat(u8 **pptr UNNEEDED, const struct amount_msat msat UNNEEDED)
{ fprintf(stderr, "towire_amount_msat called!\n"); abort(); }

14
plugins/keysend.c
View file

@ -342,6 +342,9 @@ static struct command_result *htlc_accepted_call(struct command *cmd,
struct out_req *req;
struct timeabs now = time_now();
const char *err;
u64 *allowed = tal_arr(cmd, u64, 1);
size_t err_off;
u64 err_type;
err = json_scan(tmpctx, buf, params,
"{onion:{payload:%},htlc:{payment_hash:%}}",
@ -356,10 +359,15 @@ static struct command_result *htlc_accepted_call(struct command *cmd,
if (s != max) {
return htlc_accepted_continue(cmd, NULL);
}
payload = fromwire_tlv_tlv_payload(cmd, &rawpayload, &max);
if (!payload) {
/* We explicitly allow our type. */
allowed[0] = 5482373484;
payload = tlv_tlv_payload_new(cmd);
if (!fromwire_tlv(&rawpayload, &max, tlvs_tlv_tlv_payload, TLVS_ARRAY_SIZE_tlv_tlv_payload,
payload, &payload->fields, allowed, &err_off, &err_type)) {
plugin_log(
cmd->plugin, LOG_UNUSUAL, "Malformed TLV payload %.*s",
cmd->plugin, LOG_UNUSUAL, "Malformed TLV payload type %"PRIu64" at off %zu %.*s",
err_type, err_off,
json_tok_full_len(params),
json_tok_full(buf, params));
return htlc_accepted_continue(cmd, NULL);

8
tools/gen/impl_template
View file

@ -269,16 +269,10 @@ void towire_${tlv.name}(u8 **pptr, const struct ${tlv.struct_name()} *record)
struct ${tlv.name} *fromwire_${tlv.name}(const tal_t *ctx, const u8 **cursor, size_t *max)
{
struct ${tlv.name} *record = ${tlv.name}_new(ctx);
if (!fromwire_tlv(cursor, max, tlvs_${tlv.name}, ${len(tlv.messages)}, record, &record->fields))
if (!fromwire_tlv(cursor, max, tlvs_${tlv.name}, ${len(tlv.messages)}, record, &record->fields, NULL, NULL, NULL))
return tal_free(record);
return record;
}
bool ${tlv.name}_is_valid(const struct ${tlv.struct_name()} *record, size_t *err_index)
{
return tlv_fields_valid(record->fields, NULL, err_index);
}
% endfor ## END TLV's
% for msg in messages: ## START Wire Messages

35
wire/test/run-tlvstream.c
View file

@ -468,12 +468,12 @@ int main(int argc, char *argv[])
max = tal_count(orig_p);
p = orig_p;
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert((!tlv_n1 && !p) || !tlv_n1_is_valid(tlv_n1, NULL));
assert(!tlv_n1 && !p);
assert(strstr(invalid_streams_either[i].reason, reason));
max = tal_count(orig_p);
p = orig_p;
tlv_n2 = fromwire_tlv_n2(tmpctx, &p, &max);
assert((!tlv_n2 && !p) || !tlv_n2_is_valid(tlv_n2, NULL));
assert(!tlv_n2 && !p);
assert(strstr(invalid_streams_either[i].reason, reason));
}
@ -485,7 +485,7 @@ int main(int argc, char *argv[])
p = stream(tmpctx, invalid_streams_n1[i].hex);
max = tal_count(p);
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert((!tlv_n1 && !p) || !tlv_n1_is_valid(tlv_n1, NULL));
assert(!tlv_n1 && !p);
assert(strstr(invalid_streams_n1[i].reason, reason));
}
@ -497,7 +497,7 @@ int main(int argc, char *argv[])
p = stream(tmpctx, invalid_streams_n1_combo[i].hex);
max = tal_count(p);
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert((!tlv_n1 && !p) || !tlv_n1_is_valid(tlv_n1, NULL));
assert(!tlv_n1 && !p);
assert(strstr(invalid_streams_n1_combo[i].reason, reason));
}
@ -509,8 +509,7 @@ int main(int argc, char *argv[])
p = stream(tmpctx, invalid_streams_n2_combo[i].hex);
max = tal_count(p);
tlv_n2 = fromwire_tlv_n2(tmpctx, &p, &max);
assert((!tlv_n2 && !p) ||
!tlv_n2_is_valid(tlv_n2, NULL));
assert(!tlv_n2 && !p);
assert(strstr(invalid_streams_n2_combo[i].reason, reason));
}
@ -525,8 +524,7 @@ int main(int argc, char *argv[])
max = tal_count(orig_p);
p = orig_p;
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert(tlv_n1 &&
tlv_n1_is_valid(tlv_n1, NULL));
assert(tlv_n1);
assert(max == 0);
assert(tlv_n1_eq(tlv_n1, &valid_streams[i].expect));
@ -558,13 +556,11 @@ int main(int argc, char *argv[])
max = tal_count(orig_p);
p = orig_p;
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert((!tlv_n1 && !p) ||
!tlv_n1_is_valid(tlv_n1, NULL));
assert(!tlv_n1 && !p);
max = tal_count(orig_p);
p = orig_p;
tlv_n2 = fromwire_tlv_n2(tmpctx, &p, &max);
assert((!tlv_n2 && !p) ||
!tlv_n2_is_valid(tlv_n2, NULL));
assert(!tlv_n2 && !p);
}
}
@ -578,8 +574,7 @@ int main(int argc, char *argv[])
invalid_streams_n1[i].hex);
max = tal_count(p);
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert((!tlv_n1 && !p) ||
!tlv_n1_is_valid(tlv_n1, NULL));
assert(!tlv_n1 && !p);
}
}
@ -593,8 +588,7 @@ int main(int argc, char *argv[])
invalid_streams_n1_combo[i].hex);
max = tal_count(p);
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert((!tlv_n1 && !p) ||
!tlv_n1_is_valid(tlv_n1, NULL));
assert(!tlv_n1 && !p);
}
}
@ -624,11 +618,12 @@ int main(int argc, char *argv[])
< pull_type(valid_streams[j].hex);
tlv_n1 = fromwire_tlv_n1(tmpctx, &p, &max);
assert(tlv_n1 &&
tlv_n1_is_valid(tlv_n1, NULL) == expect_success);
if (!expect_success)
if (!expect_success) {
assert(!tlv_n1);
continue;
}
assert(tlv_n1);
/* Re-encoding should give the same results (except
* ignored fields tests!) */

170
wire/tlvstream.c
View file

@ -110,10 +110,39 @@ size_t tlv_field_offset(const u8 *tlvstream, size_t tlvlen, u64 fieldtype)
return tlvlen;
}
static bool tlv_type_is_allowed(const struct tlv_field *f,
const u64 *extra_types)
{
/* Simple case: it's an odd field. */
if (f->numtype % 2 != 0)
return true;
/* Now iterate through the extras and see if we should make an
* exception. */
for (size_t i = 0; i < tal_count(extra_types); i++)
if (extra_types[i] == f->numtype)
return true;
return false;
}
/* Update err_off to point to current offset. */
static void update_err_off(size_t *err_off, size_t initial_len, size_t max)
{
if (err_off)
*err_off = initial_len - max;
}
bool fromwire_tlv(const u8 **cursor, size_t *max,
const struct tlv_record_type *types, size_t num_types,
void *record, struct tlv_field **fields)
void *record, struct tlv_field **fields,
const u64 *extra_types,
size_t *err_off, u64 *err_type)
{
bool first = true;
u64 prev_type = 0;
size_t initial_len = *max;
update_err_off(err_off, initial_len, *max);
while (*max > 0) {
struct tlv_field field;
@ -129,8 +158,52 @@ bool fromwire_tlv(const u8 **cursor, size_t *max,
*/
if (!*cursor) {
SUPERVERBOSE("type");
if (err_type)
*err_type = 0;
goto fail;
}
/* BOLT #1:
* - if decoded `type`s are not strictly-increasing
* (including situations when two or more occurrences
* of the same `type` are met):
* - MUST fail to parse the `tlv_stream`.
*/
if (!first && field.numtype <= prev_type) {
if (field.numtype == prev_type)
SUPERVERBOSE("duplicate tlv type");
else
SUPERVERBOSE("invalid ordering");
if (err_type)
*err_type = field.numtype;
goto fail;
}
first = false;
prev_type = field.numtype;
/* BOLT #1:
* - if `type` is known:
* - MUST decode the next `length` bytes using the known
* encoding for `type`.
*/
field.meta = NULL;
for (size_t i = 0; i < num_types; i++) {
if (types[i].type == field.numtype) {
field.meta = &types[i];
break;
}
}
if (!field.meta && !tlv_type_is_allowed(&field, extra_types)) {
SUPERVERBOSE("unknown even");
if (err_type != NULL)
*err_type = field.numtype;
goto fail;
}
/* We're happy with type field. Move on. */
update_err_off(err_off, initial_len, *max);
field.length = fromwire_bigsize(cursor, max);
/* BOLT #1:
@ -139,6 +212,8 @@ bool fromwire_tlv(const u8 **cursor, size_t *max,
*/
if (!*cursor) {
SUPERVERBOSE("length");
if (err_type)
*err_type = field.numtype;
goto fail;
}
@ -149,28 +224,31 @@ bool fromwire_tlv(const u8 **cursor, size_t *max,
*/
if (field.length > *max) {
SUPERVERBOSE("value");
if (err_type)
*err_type = field.numtype;
goto fail;
}
field.value = tal_dup_arr(record, u8, *cursor, field.length, 0);
/* BOLT #1:
* - if `type` is known:
* - MUST decode the next `length` bytes using the known
* encoding for `type`.
*/
field.meta = NULL;
for (size_t i = 0; i < num_types; i++) {
if (types[i].type == field.numtype)
field.meta = &types[i];
}
/* We're happy with length field. Move on. */
update_err_off(err_off, initial_len, *max);
field.value = tal_dup_arr(record, u8, *cursor, field.length, 0);
if (field.meta) {
/* Length of message can't exceed 16 bits anyway. */
size_t tlvlen = field.length;
/* We're happy with type field. Move on. */
update_err_off(err_off, initial_len, *max);
/* FIXME: We could add an err_off in here for more accuracy. */
field.meta->fromwire(cursor, &tlvlen, record);
if (!*cursor)
if (!*cursor) {
if (err_type != NULL)
*err_type = field.numtype;
goto fail;
}
/* BOLT #1:
* - if `length` is not exactly equal to that required
@ -178,16 +256,25 @@ bool fromwire_tlv(const u8 **cursor, size_t *max,
* - MUST fail to parse the `tlv_stream`.
*/
if (tlvlen != 0) {
if (err_type != NULL)
*err_type = field.numtype;
SUPERVERBOSE("greater than encoding length");
goto fail;
}
} else {
/* We're happy with type field. Move on. */
update_err_off(err_off, initial_len, *max);
/* We didn't read from *cursor through a fromwire, so
* update manually. */
*cursor += field.length;
}
/* We've read bytes in ->fromwire, so update max */
*max -= field.length;
/* We're happy with contents. Move on. */
update_err_off(err_off, initial_len, *max);
tal_arr_expand(fields, field);
}
return true;
@ -196,63 +283,6 @@ fail:
return false;
}
static bool tlv_type_is_allowed(const struct tlv_field *f, u64 *extra_types) {
/* Simple case: we have internal meta fields or it's an odd field. */
if (f->numtype % 2 != 0 || f->meta != NULL)
return true;
if (extra_types == NULL)
return false;
/* Now iterate through the extras and see if we should make an
* exception. */
for (size_t i = 0; i < tal_count(extra_types); i++)
if (extra_types[i] == f->numtype)
return true;
return false;
}
bool tlv_fields_valid(const struct tlv_field *fields, u64 *allow_extra,
size_t *err_index)
{
size_t numfields = tal_count(fields);
bool first = true;
u64 prev_type = 0;
for (int i=0; i<numfields; i++) {
const struct tlv_field *f = &fields[i];
if (!tlv_type_is_allowed(f, allow_extra)) {
/* 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.
*/
SUPERVERBOSE("unknown even");
if (err_index != NULL)
*err_index = i;
return false;
} else if (!first && f->numtype <= prev_type) {
/* BOLT #1:
* - if decoded `type`s are not strictly-increasing
* (including situations when two or more occurrences
* of the same `type` are met):
* - MUST fail to parse the `tlv_stream`.
*/
if (f->numtype == prev_type)
SUPERVERBOSE("duplicate tlv type");
else
SUPERVERBOSE("invalid ordering");
if (err_index != NULL)
*err_index = i;
return false;
}
first = false;
prev_type = f->numtype;
}
return true;
}
void towire_tlv(u8 **pptr,
const struct tlv_record_type *types, size_t num_types,
const void *record)

17
wire/tlvstream.h
View file

@ -38,15 +38,24 @@ struct tlv_field *tlv_make_fields_(const struct tlv_record_type *types,
size_t num_types,
const void *record);
/* Generic TLV decode/encode */
/**
* fromwire_tlv: generic TLV decode engine
* @cursor: cursor to update (set to NULL if we fail).
* @max: max len to update (always set to 0 if we succeed).
* @types / @num_types: table of known tlv types
* @record: the tlv to hand to @type-specific decode
* @fields: the fields array to populate
* @extra_types: tal_arr or NULL of unknown types to allow
* @err_off: NULL, or set to offset in tlv stream which failed.
* @err_type: NULL, or set to tlv type which failed (or 0 if malformed)
*/
bool fromwire_tlv(const u8 **cursor, size_t *max,
const struct tlv_record_type *types, size_t num_types,
void *record, struct tlv_field **fields);
void *record, struct tlv_field **fields,
const u64 *extra_types, size_t *err_off, u64 *err_type);
void towire_tlv(u8 **pptr,
const struct tlv_record_type *types, size_t num_types,
const void *record);
bool tlv_fields_valid(const struct tlv_field *fields, u64 *allow_extra,
size_t *err_index);
/* Get the offset of this field: returns size of msg if not found (or
* tlv malformed) */