DanielLavrushin/b4 v1.20.1

on GitHub

[1.20.1] - 2025-12-03

• FIXED: IPv4 UDP fragmentation using incorrect fragment offset encoding (wrong bit shifts corrupted offset field).
• FIXED: IPv6 IP-level fragmentation not adjusting split position relative to IP payload, causing incorrect fragment boundaries.
• FIXED: IP-level fragmentation (IPv4/IPv6) ignoring Smart SNI Split option - now uses middle_sni when enabled.
• FIXED: QUIC fragmentation (IPv4/IPv6) had inverted ReverseOrder logic - was sending in reverse when disabled and normal when enabled.
• FIXED: OOB fragmentation strategy was sending OOB byte in real packet that reached server, breaking TLS handshake. Now sends OOB as fake packet with low TTL/hop limit that dies in transit - DPI sees garbage, server receives clean data.
• FIXED: Discovery service testing all presets with single hardcoded fake SNI payload - if user's DPI only responds to alternate payload, most strategies would incorrectly fail.
• FIXED: OOB seg2 sequence number calculation was incorrect (added +1 for fake byte), causing TCP reassembly failures.
• ADDED: QUIC SNI-aware fragmentation - fragments now split at the actual SNI position within encrypted QUIC payloads, defeating DPI systems that decrypt QUIC Initial packets to inspect SNI.
• ADDED: OOB now supports tcp_check and md5sum faking strategies for checksum corruption fallback when TTL-based faking is unreliable.
• ADDED: [EXPERIMENTAL] DPI Fingerprinting in Discovery - attempts to identify DPI type and blocking method before testing, prioritizing likely-effective strategies based on failure mode analysis. May produce inaccurate results; falls back automatically to full preset scan when fingerprint is inconclusive.
• ADDED: Multiple built-in fake SNI payloads (FakeSNI1: google (default, AKA classic), FakeSNI2: duckduckgo) - different DPI systems respond to different payloads.
• ADDED: Discovery now auto-detects working payload early and applies it to all subsequent tests; if neither works initially, tests both per-strategy and learns dynamically.
• ADDED: User-selectable fake payload type in Faking settings (Random, Custom, or built-in presets).
• IMPROVED: Fragmentation UI - renamed "Middle SNI" to "Smart SNI Split", added visual packet diagram, moved manual position to collapsible advanced section.

Full Changelog: v1.20.0...v1.20.1