Fix Mihomo Hysteria2 Gecko obfs mapping

[Medium1992]

Maps Hysteria2 finalmask packetSize obfs to Mihomo Gecko fields.

Keeps plain Salamander output unchanged when packetSize is not set.

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[what-the-diff]

PR Summary

• Updated Interface Definition
  The structure of the Hysteria2FinalMask interface has been modified for improved flexibility. A new optional attribute, packetSize, has been added to the settings within the udp group.

• Modified Data Handling Method
  The method responsible for data extraction, named buildHysteria2ObfsFields, has been enhanced to accommodate more data types. It's now able to handle both 'salamander' and 'gecko' types from the udp array and retrieves the related properties according to the updated structure.

• Improved Decision-Making Process
  Changes have been introduced to the buildHysteria2ObfsFields method for better decision-making. It now includes additional conditions that handle the new packetSize settings. This enhancement allows the method to provide different output depending on the mask type and whether or not the packet size fields are present.

• Created Dedicated Method for Packet Sizes
  With the addition of a new method, buildHysteria2PacketSizeFields, there's now a dedicated process for handling packetSize attributes. This method extracts and validates min and max packet sizes from the packetSize, and if they're acceptable, it presents these values in the required format.

[greptile-apps]

Greptile Summary

This PR extends buildHysteria2ObfsFields to recognise both salamander and gecko obfs types in the Hysteria2 finalmask, and adds a new buildHysteria2PacketSizeFields helper that parses a "min-max" range string into Mihomo's obfs-min-packet-size / obfs-max-packet-size fields.

• When the source type is salamander and no packetSize is present the output is unchanged (obfs: salamander); otherwise the output is promoted to obfs: gecko with optional packet-size bounds.
• The new buildHysteria2PacketSizeFields helper splits packetSize on - to extract min and max, guards against non-positive or non-finite values, and is a no-op when packetSize is absent.

Confidence Score: 3/5

The logic change is small and well-scoped but contains a TypeScript compile error that would break the build.

With strict: true and strictNullChecks: true in the project's tsconfig.json, accessing mask.type directly on a value typed T | undefined (returned by Array.find) is a compile-time error. The earlier if (!password) return {} guard makes the access safe at runtime, but TypeScript's control-flow analysis does not narrow mask through the optional-chaining read of password, so the build would fail until this is fixed.

src/modules/subscription-template/generators/mihomo.generator.service.ts — specifically the mask.type access on line 659 and the single-value packetSize parsing behaviour in buildHysteria2PacketSizeFields.

Important Files Changed

Filename	Overview
src/modules/subscription-template/generators/mihomo.generator.service.ts	Adds gecko obfs support and packet-size range parsing for Hysteria2 Mihomo output; contains a strictNullChecks compile error on mask.type and a minor ambiguity when packetSize is a plain number.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[buildHysteria2ObfsFields] --> B[Find udp entry: salamander or gecko]
    B --> C{mask found?}
    C -- no --> D[return empty]
    C -- yes --> E{password present?}
    E -- no --> D
    E -- yes --> F[buildHysteria2PacketSizeFields]
    F --> G{packetSize present?}
    G -- no --> H[packetSizeFields is empty]
    G -- yes --> I[split on dash, validate min and max]
    I --> J[populate packetSizeFields]
    H --> K{mask.type is salamander AND packetSizeFields empty?}
    J --> K
    K -- yes --> L[return obfs salamander]
    K -- no --> M[return obfs gecko plus packetSizeFields]

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A[buildHysteria2ObfsFields] --> B[Find udp entry: salamander or gecko]
    B --> C{mask found?}
    C -- no --> D[return empty]
    C -- yes --> E{password present?}
    E -- no --> D
    E -- yes --> F[buildHysteria2PacketSizeFields]
    F --> G{packetSize present?}
    G -- no --> H[packetSizeFields is empty]
    G -- yes --> I[split on dash, validate min and max]
    I --> J[populate packetSizeFields]
    H --> K{mask.type is salamander AND packetSizeFields empty?}
    J --> K
    K -- yes --> L[return obfs salamander]
    K -- no --> M[return obfs gecko plus packetSizeFields]

Loading

_{Reviews (1): Last reviewed commit: "fix: map hysteria2 gecko obfs for mihomo" | Re-trigger Greptile}

[kastov]

Можете уточнить, что это за параметры?
В оф. документации их не вижу: https://wiki.metacubex.one/config/proxies/hysteria2

[Medium1992]

Можете уточнить, что это за параметры? В оф. документации их не вижу: https://wiki.metacubex.one/config/proxies/hysteria2

https://github.com/MetaCubeX/mihomo/blob/5184081ac327394d9e15fa5d5f9f4a61e723fd94/docs/config.yaml#L1058
строки 1058-1061

Маленький тест уже провели, параметры передаются в yaml конфиге и hy2 в михомо с gecko начинает работать

Коммит
MetaCubeX/mihomo@f30a64f
Gecko есть в текущем stable mihomo

[spectreq666]

Тесты проводились с данным профилем ноды remnawave/templates#89

С вмонтированным генератором из PR Gecko корректно заработал на Mihomo

[kastov]

Тесты проводились с данным профилем ноды remnawave/templates#89

С вмонтированным генератором из PR Gecko корректно заработал на Mihomo

В нем же type: "salamander", а не "gecko".

[spectreq666]

Тесты проводились с данным профилем ноды remnawave/templates#89
С вмонтированным генератором из PR Gecko корректно заработал на Mihomo

В нем же type: "salamander", а не "gecko".

https://xtls.github.io/ru/config/transports/finalmask.html#gecko
Gecko - "надстройка" над Salamander, исходя из документации Xray
type: "gecko" не существует в реализации Xray, он начинает работать, когда указывается "packetSize"

[Medium1992]

Тесты проводились с данным профилем ноды remnawave/templates#89
С вмонтированным генератором из PR Gecko корректно заработал на Mihomo

В нем же type: "salamander", а не "gecko".

Работает только если указать gecko в mihomo
При указании salamander в mihomo, не учитываются поля min max

[spectreq666]

Тесты проводились с данным профилем ноды remnawave/templates#89
С вмонтированным генератором из PR Gecko корректно заработал на Mihomo

В нем же type: "salamander", а не "gecko".

Работает только если указать gecko При указании salamander в mihomo, не учитываются поля min max

Верно, в реализации Mihomo есть напрямую gecko.
у Xray ее нет.