Merge pull request #167 from oif/add-documentation-about-saltfilter

Add documentation about saltfilter and tidy go mod

Author: riobard

README.md

@@ -119,6 +119,22 @@ It will look for the plugin in the current directory first, then `$PATH`.
 
 UDP connections will not be affected by SIP003.
 
+### Reuse Detection
+
+This feature used for resistance with reuse attack by checking cipher salt/iv is repeated.
+
+Expose some environment variables below to control this feature:
+- `SHADOWSOCKS_SF_CAPACITY`(an integer): The most recently salt items to keep for checking duplication. Default 1e6, 
+on gave a non-positive integer this feature will be disabled;
+- `SHADOWSOCKS_SF_FPR`(decimal): False positive rate of the filter, 0.0003 means 0.03% FPR. Default 1e-6;
+- `SHADOWSOCKS_SF_SLOT`(a positive integer): All the salt items will be added into lots(how many this variable defines) 
+filter items for the check. Default 10.
+
+
+```sh
+SHADOWSOCKS_SF_CAPACITY=1e6 SHADOWSOCKS_SF_FPR=1e-6 SHADOWSOCKS_SF_SLOT=10 go-shadowsocks2 ...
+```
+
 ## Design Principles
 
 The code base strives to

go.sum

@@ -8,7 +8,5 @@ github.com/golang/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:5JyrLPvD/ZdaY
 github.com/golang/sys v0.0.0-20190412213103-97732733099d h1:blRtD+FQOxZ6P7jigy+HS0R8zyGOMOv8TET4wCpzVwM=
 github.com/golang/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 github.com/golang/text v0.3.0/go.mod h1:GUiq9pdJKRKKAZXiVgWFEvocYuREvC14NhI4OPgEjeE=
-github.com/riobard/go-bloom v0.0.0-20170218180955-2b113c64a69b h1:H9yjH/g5w8MOPjQR2zMSP/Md1kKtj/33fIht9ChC2OU=
-github.com/riobard/go-bloom v0.0.0-20170218180955-2b113c64a69b/go.mod h1:HgjTstvQsPGkxUsCd2KWxErBblirPizecHcpD3ffK+s=
 github.com/riobard/go-bloom v0.0.0-20200213042214-218e1707c495 h1:p7xbxYTzzfXghR1kpsJDeoVVRRWAotKc8u7FP/N48rU=
 github.com/riobard/go-bloom v0.0.0-20200213042214-218e1707c495/go.mod h1:HgjTstvQsPGkxUsCd2KWxErBblirPizecHcpD3ffK+s=