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common/sphinx: handle decoding of TLV payload.

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We add routines to decode the expected fields from both legacy and tlv
hop formats.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2019-11-14 10:44:53 +10:30
committed by Christian Decker
parent a76518a029
commit b7bbccd6fa
5 changed files with 168 additions and 2 deletions
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102
common/sphinx.c
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@@ -477,16 +477,31 @@ static void sphinx_parse_payload(struct route_step *step, const u8 *src)
}
#endif
/* Legacy hop_data support */
/* BOLT #4:
*
* The `length` field determines both the length and the format of the
* `hop_payload` field; the following formats are defined:
*
* - Legacy `hop_data` format, identified by a single `0x00` byte for
* length. In this case the `hop_payload_length` is defined to be 32
* bytes.
*
* - `tlv_payload` format, identified by any length over `1`. In this
* case the `hop_payload_length` is equal to the numeric value of
* `length`.
*/
if (src[0] == 0x00) {
vsize = 1;
raw_size = 32;
hop_size = FRAME_SIZE;
step->type = SPHINX_V0_PAYLOAD;
} else {
} else if (src[0] > 1) {
vsize = bigsize_get(src, 3, &raw_size);
hop_size = raw_size + vsize + HMAC_SIZE;
step->type = SPHINX_TLV_PAYLOAD;
} else {
step->type = SPHINX_INVALID_PAYLOAD;
return;
}
/* Copy common pieces over */
@@ -497,6 +512,18 @@ static void sphinx_parse_payload(struct route_step *step, const u8 *src)
* later. */
if (step->type == SPHINX_V0_PAYLOAD)
deserialize_hop_data(&step->payload.v0, src);
else if (step->type == SPHINX_TLV_PAYLOAD) {
const u8 *tlv = step->raw_payload;
size_t max = tal_bytelen(tlv);
step->payload.tlv = tlv_tlv_payload_new(step);
if (!fromwire_tlvs(&tlv, &max, tlvs_tlv_payload,
TLVS_TLV_PAYLOAD_ARRAY_SIZE,
step->payload.tlv)) {
/* FIXME: record offset of violation for error! */
step->type = SPHINX_INVALID_PAYLOAD;
return;
}
}
}
struct onionpacket *create_onionpacket(
@@ -781,3 +808,74 @@ struct onionreply *unwrap_onionreply(const tal_t *ctx,
return oreply;
}
/**
* Helper to extract fields from ONION_END.
*/
bool route_step_decode_end(const struct route_step *rs,
struct amount_msat *amt_forward,
u32 *outgoing_cltv)
{
assert(rs->nextcase == ONION_END);
switch (rs->type) {
case SPHINX_V0_PAYLOAD:
*amt_forward = rs->payload.v0.amt_forward;
*outgoing_cltv = rs->payload.v0.outgoing_cltv;
return true;
case SPHINX_TLV_PAYLOAD:
if (!rs->payload.tlv->amt_to_forward)
return false;
amt_forward->millisatoshis /* Raw: tu64 -> millisatoshis */
= rs->payload.tlv->amt_to_forward->amt_to_forward;
if (!rs->payload.tlv->outgoing_cltv_value)
return false;
*outgoing_cltv = rs->payload.tlv->outgoing_cltv_value->outgoing_cltv_value;
return true;
case SPHINX_INVALID_PAYLOAD:
return false;
/* This should probably be removed, as it's just for testing */
case SPHINX_RAW_PAYLOAD:
abort();
}
abort();
}
/**
* Helper to extract fields from ONION_FORWARD.
*/
bool route_step_decode_forward(const struct route_step *rs,
struct amount_msat *amt_forward,
u32 *outgoing_cltv,
struct short_channel_id *scid)
{
assert(rs->nextcase == ONION_FORWARD);
switch (rs->type) {
case SPHINX_V0_PAYLOAD:
*amt_forward = rs->payload.v0.amt_forward;
*outgoing_cltv = rs->payload.v0.outgoing_cltv;
*scid = rs->payload.v0.channel_id;
return true;
case SPHINX_TLV_PAYLOAD:
if (!rs->payload.tlv->amt_to_forward)
return false;
amt_forward->millisatoshis /* Raw: tu64 -> millisatoshis */
= rs->payload.tlv->amt_to_forward->amt_to_forward;
if (!rs->payload.tlv->outgoing_cltv_value)
return false;
*outgoing_cltv = rs->payload.tlv->outgoing_cltv_value->outgoing_cltv_value;
if (!rs->payload.tlv->short_channel_id)
return false;
*scid = rs->payload.tlv->short_channel_id->short_channel_id;
return true;
case SPHINX_INVALID_PAYLOAD:
return false;
/* This should probably be removed, as it's just for testing */
case SPHINX_RAW_PAYLOAD:
abort();
}
abort();
}