TransportDVBoxMessage Struct Reference

Outer layer of an encapsulated message send over multiple hops. More...

Collaboration diagram for TransportDVBoxMessage:

Data Fields
struct GNUNET_MessageHeader	header
	Type is GNUNET_MESSAGE_TYPE_TRANSPORT_DV_BOX.
uint32_t	without_fc
	Flag if the payload is a control message.
uint16_t	total_hops
	Number of total hops this messages travelled.
uint16_t	num_hops
	Number of hops this messages includes.
struct GNUNET_CRYPTO_HpkeEncapsulation	ephemeral_key
	Ephemeral key setup by the sender for target, used to encrypt the payload.
struct GNUNET_CRYPTO_AeadNonce	iv
	We use an IV here as the ephemeral_key is reused for EPHEMERAL_VALIDITY time to avoid re-signing it all the time.
struct GNUNET_CRYPTO_AeadMac	mac
	HMAC over the ciphertext of the encrypted, variable-size body that follows.
uint16_t	orig_size
	Size this msg had initially.

Detailed Description

Outer layer of an encapsulated message send over multiple hops.

The path given only includes the identities of the subsequent peers, i.e. it will be empty if we are the receiver. Each forwarding peer should scan the list from the end, and if it can, forward to the respective peer. The list should then be shortened by all the entries up to and including that peer. Each hop should also increment total_hops to allow the receiver to get a precise estimate on the number of hops the message travelled. Senders must provide a learned path that thus should work, but intermediaries know of a shortcut, they are allowed to send the message via that shortcut.

If a peer finds itself still on the list, it must drop the message.

The payload of the box can only be decrypted and verified by the ultimate receiver. Intermediaries do not learn the sender's identity and the path the message has taken. However, the first hop does learn the sender as total_hops would be zero and thus the predecessor must be the origin (so this is not really useful for anonymization).

Definition at line 890 of file gnunet-service-transport.c.

Field Documentation

header

struct GNUNET_MessageHeader TransportDVBoxMessage::header

Type is GNUNET_MESSAGE_TYPE_TRANSPORT_DV_BOX.

Definition at line 895 of file gnunet-service-transport.c.

Referenced by check_dv_box(), decaps_dv_box_cont(), encapsulate_for_dv(), forward_dv_box(), and handle_dv_box().

without_fc

uint32_t TransportDVBoxMessage::without_fc

Flag if the payload is a control message.

In NBO.

Definition at line 900 of file gnunet-service-transport.c.

Referenced by encapsulate_for_dv(), and forward_dv_box().

total_hops

uint16_t TransportDVBoxMessage::total_hops

Number of total hops this messages travelled.

In NBO. origin sets this to zero, to be incremented at each hop. Peers should limit the total_hops value they accept from other peers.

Definition at line 908 of file gnunet-service-transport.c.

Referenced by check_dv_box(), encapsulate_for_dv(), forward_dv_box(), and handle_dv_box().

num_hops

uint16_t TransportDVBoxMessage::num_hops

Number of hops this messages includes.

In NBO. Reduced by one or more at each hop. Peers should limit the num_hops value they accept from other peers.

Definition at line 915 of file gnunet-service-transport.c.

Referenced by check_dv_box(), encapsulate_for_dv(), forward_dv_box(), and handle_dv_box().

ephemeral_key

struct GNUNET_CRYPTO_HpkeEncapsulation TransportDVBoxMessage::ephemeral_key

Ephemeral key setup by the sender for target, used to encrypt the payload.

Intermediaries must not change this value.

Definition at line 921 of file gnunet-service-transport.c.

Referenced by decaps_dv_box_cont(), encapsulate_for_dv(), and handle_dv_box().

iv

struct GNUNET_CRYPTO_AeadNonce TransportDVBoxMessage::iv

We use an IV here as the ephemeral_key is reused for EPHEMERAL_VALIDITY time to avoid re-signing it all the time.

Intermediaries must not change this value.

Definition at line 928 of file gnunet-service-transport.c.

Referenced by decaps_dv_box_cont(), and encapsulate_for_dv().

mac

struct GNUNET_CRYPTO_AeadMac TransportDVBoxMessage::mac

HMAC over the ciphertext of the encrypted, variable-size body that follows.

Verified via DH of target and ephemeral_key. Intermediaries must not change this value.

Definition at line 935 of file gnunet-service-transport.c.

Referenced by decaps_dv_box_cont(), and encapsulate_for_dv().

orig_size

uint16_t TransportDVBoxMessage::orig_size

Size this msg had initially.

This is needed to calculate the hmac at the target. The header size can not be used for that, because the box size is getting smaller at each hop.

Definition at line 942 of file gnunet-service-transport.c.

Referenced by check_dv_box(), and encapsulate_for_dv().

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The documentation for this struct was generated from the following file:

• src/service/transport/gnunet-service-transport.c