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Flesh out doc string for ForwardingMessage and a few others

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* Next step is to write the logic for processing mix messages
This commit is contained in:
Olaoluwa Osuntokun 2015-10-17 14:56:24 -07:00
parent 1b98267ca4
commit 3838b2333b
1 changed files with 26 additions and 9 deletions
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35
sphinx.go
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@ -217,15 +217,31 @@ func generateHeaderPadding(numHops int, sharedSecrets [][sharedSecretSize]byte)
return filler
}
// CreateForwardingMessage...
func CreateForwardingMessage(route []*btcec.PublicKey, dest LnAddr,
identifier [securityParameter]byte, message []byte) (*MixHeader, *[messageSize]byte, error) {
// ForwardingMessage represents a forwarding message containing onion wrapped
// hop-to-hop routing information along with an onion encrypted payload message
// addressed to the final destination.
// TODO(roasbeef): serialize/deserialize methods..
type ForwardingMessage struct {
header *MixHeader
msg [messageSize]byte
}
// NewForwardingMessage generates the a mix header containing the neccessary
// onion routing information required to propagate the message through the
// mixnet, eventually reaching the final node specified by 'identifier'. The
// onion encrypted message payload is then to be delivered to the specified 'dest'
// address.
func NewForwardingMessage(route []*btcec.PublicKey, dest LnAddr,
identifier [securityParameter]byte, message []byte) (*ForwardingMessage, error) {
routeLength := len(route)
// Compute the mix header, and shared secerts for each hop.
mixHeader, secrets, err := GenerateSphinxHeader([]byte{nullDest}, zeroNode, route)
// Compute the mix header, and shared secerts for each hop. We pass in
// the null destinatino and zero identifier in order for the final node
// in the route to be able to distinguish the payload as addressed to
// itself.
mixHeader, secrets, err := NewMixHeader([]byte{nullDest}, zeroNode, route)
if err != nil {
return nil, nil, err
return nil, err
}
// Now for the body of the message. The next-node ID is set to all
@ -247,10 +263,11 @@ func CreateForwardingMessage(route []*btcec.PublicKey, dest LnAddr,
onion = lionessEncode(generateKey("pi", secrets[i]), onion)
}
return mixHeader, &onion, nil
return &ForwardingMessage{header: mixHeader, msg: onion}, nil
}
// calcMac....
// calcMac calculates HMAC-SHA-256 over the message using the passed secret key as
// input to the HMAC.
func calcMac(key [securityParameter]byte, msg []byte) [securityParameter]byte {
hmac := hmac.New(sha256.New, key[:])
hmac.Write(msg)
@ -262,7 +279,7 @@ func calcMac(key [securityParameter]byte, msg []byte) [securityParameter]byte {
return mac
}
// xor...
// xor computes the byte wise XOR of a and b, storing the result in dst.
func xor(dst, a, b []byte) int {
n := len(a)
if len(b) < n {