| | | 1 | | using System.Diagnostics; |
| | | 2 | | |
| | | 3 | | namespace NLightning.Infrastructure.Transport.Handshake.MessagePatterns; |
| | | 4 | | |
| | | 5 | | using Domain.Crypto.Constants; |
| | | 6 | | using Enums; |
| | | 7 | | |
| | | 8 | | /// <summary> |
| | | 9 | | /// A message pattern is some sequence of tokens from |
| | | 10 | | /// the set ("e", "s", "ee", "es", "se", "ss", "psk"). |
| | | 11 | | /// </summary> |
| | | 12 | | internal sealed class MessagePattern |
| | | 13 | | { |
| | 12 | 14 | | internal MessagePattern(params Token[] tokens) |
| | | 15 | | { |
| | | 16 | | Debug.Assert(tokens != null); |
| | | 17 | | Debug.Assert(tokens.Length > 0); |
| | | 18 | | |
| | 12 | 19 | | Tokens = tokens; |
| | 12 | 20 | | } |
| | | 21 | | |
| | | 22 | | /// <summary> |
| | | 23 | | /// Gets the tokens of the message pattern. |
| | | 24 | | /// </summary> |
| | 420 | 25 | | internal IEnumerable<Token> Tokens { get; } |
| | | 26 | | |
| | | 27 | | /// <summary> |
| | | 28 | | /// Calculate the message overhead in bytes (i.e. the |
| | | 29 | | /// total size of all transmitted keys and AEAD tags). |
| | | 30 | | /// </summary> |
| | | 31 | | internal int Overhead(int dhLen, bool hasKey) |
| | | 32 | | { |
| | | 33 | | // Overhead always includes the Version length, which is 1 byte |
| | 216 | 34 | | var overhead = 1; |
| | | 35 | | |
| | 1296 | 36 | | foreach (var token in Tokens) |
| | | 37 | | { |
| | | 38 | | switch (token) |
| | | 39 | | { |
| | | 40 | | case Token.E: |
| | 168 | 41 | | overhead += dhLen; |
| | 168 | 42 | | break; |
| | | 43 | | case Token.S: |
| | 48 | 44 | | overhead += hasKey ? dhLen + CryptoConstants.CHACHA20_POLY1305_TAG_LEN : dhLen; |
| | 48 | 45 | | break; |
| | | 46 | | case Token.EE: |
| | | 47 | | case Token.SE: |
| | | 48 | | case Token.ES: |
| | | 49 | | case Token.SS: |
| | | 50 | | default: |
| | 216 | 51 | | hasKey = true; |
| | | 52 | | break; |
| | | 53 | | } |
| | | 54 | | } |
| | | 55 | | |
| | 216 | 56 | | return hasKey ? overhead + CryptoConstants.CHACHA20_POLY1305_TAG_LEN : overhead; |
| | | 57 | | } |
| | | 58 | | } |