[bug] Protocol issues

[farmage]

🐛 BUG REPORT

debug log shows some issues with messages sent by some nodes
if node can't get previeous_hash and block_height it still sends messages with empty block_height and previous_block_hash
example:

Function Calls:       
#1 validate_data: Invalid message
                                                                                               
MESSAGE: {     
 "message_settings": "SEND_CURRENT_BLOCK_HEIGHT",
 "block_height": "",
"public_address": "XCA1imCxpjCYT5VdcNdkA6FQMR3BFkPUdRSXc3Hj4QXGHrnuyTMauxGEnq8pCP82cXMWFRyZHU8UKCZjGMYBAfYq2fFdgzVYcg",
 "previous_block_hash": "",   

Another issue - some messages have no public_address field. That's leading to a validation error.

validate_data: Error
Sun 22 Aug 2021 19:45:39 UTC
-----------------------------------------------------------------------------------------------
Function Calls:
#1 validate_data: Invalid message

MESSAGE: {
 "message_settings": "BLOCK_VERIFIERS_TO_BLOCK_VERIFIERS_ONLINE_STATUS",
}

The same issue with 'non-standard' messages

Function Calls:
#1 verify_data: Could not find the public key to verify the message

MESSAGE: NODE_TO_BLOCK_VERIFIERS_GET_RESERVE_BYTES_DATABASE_HASH|850951|XCA1pBdRSiveCMWgkbExKXW1D8UcjeDuHh72oKvmApYaPmKhWDnS18M9M4pyM2aXiFKHVdeBCgq6dWVjJwRegRTa543gaesH2M|RSx1Ips4ViIYF0zrWpDiOuPwhUcm40cLJyBfNR9zZHnuvKJiZaoCs1YzLYLFPMfmaEpNlma8RnqcVXiJXx9fmVCYJdrmNuyNYLp7|f41ec9ce7110f8cd311aff4b5d20bde4275cb58e5f0f4f8284112bd40c4c350a88210a88317c6c8a4922037245f431

[zachhildreth]

Hi @farmage

For the first one it does check the block hash, but does need a check for the block height, but as long as the error happens "honestly" it should still invalidate the message
https://github.com/X-CASH-official/xcash-dpops/blob/master/src/functions/network_functions/network_security_functions/network_security_functions.c#L686

For the second one that is by design, as it sends out a dummy message after a successful creation of the socket to check if we could send any data to the delegate. If not then their offline
https://github.com/X-CASH-official/xcash-dpops/blob/master/src/functions/block_verifiers_functions/block_verifiers_update_functions/block_verifiers_update_functions.c#L1255

For the third one, that is correct. If a xcashd sends that type of message with a public address and key, then it gets validated by the delegates that they are part of db of delegates when the DDOS check happens. If a node just sends the block height then it just checks the IP for DDOS

so the above would error if that delegate is not in the db