commit a28dc7176d4e70313d45361e3e1f9d3999098a75 Author: Nick Mathewson nickm@torproject.org Date: Wed Dec 9 13:18:43 2020 -0500

Document consensus method 31 as a fix for bug #19011. --- dir-spec.txt | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/dir-spec.txt b/dir-spec.txt index 148163d..668ff32 100644 --- a/dir-spec.txt +++ b/dir-spec.txt @@ -2805,6 +2805,10 @@ * If consensus method 30 or later is used, the base64 encoded ntor-onion-key does not include the trailing = sign.

+ * If consensus method 31 or later is used, authorities parse the + "bwweightscale" and "maxunmeasuredbw" parameters correctly when + computing votes. + The signatures at the end of a consensus document are sorted in ascending order by identity digest.

@@ -2891,6 +2895,8 @@ "28" -- Removes "a" lines from microdescriptors. "29" -- Canonicalizes families in microdescriptors. "30" -- Removes padding from ntor-onion-key. + "31" -- Uses correct parsing for bwweightscale and maxunmeasuredbw + when computing weights

Before generating a consensus, an authority must decide which consensus method to use. To do this, it looks for the highest version number @@ -2938,7 +2944,11 @@

3.8.3. Computing Bandwidth Weights

- Let weight_scale = 10000 + Let weight_scale = 10000, or the value of the "bwweightscale" parameter. + (Before consensus method 31 there was a bug in parsing bwweightscale, so + that if there were any consensus parameters after it alphabetically, it + would always be treated as 10000. A similar bug existed for + "maxunmeasuredbw".)

Starting with consensus method 26, G, M, E, and D are initialized to 1 and T to 4. Prior consensus methods initialize them all to 0. With this change, @@ -3091,7 +3101,8 @@

To ensure consensus, all calculations are performed using integer math with a fixed precision determined by the bwweightscale consensus - parameter (defaults at 10000, Min: 1, Max: INT32_MAX). + parameter (defaults at 10000, Min: 1, Max: INT32_MAX). (See note above + about parsing bug in bwweightscale before consensus method 31.)

For future balancing improvements, Tor clients support 11 additional weights for directory requests and middle weighting. These weights are currently