CANGW(1)

✨ NAME ✨

hiii bestie, meet cangw 💖 — she's the manual page for cangw 2023.03-1build1, living her best life in the CANGW(1) section of the User Commands chapter. her whole thing? managing the PF_CAN netlink gateway. that's it, that's the girl. 🦋

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🌸 SYNOPSIS 🌸

cangw [options]

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🎀 DESCRIPTION 🎀

okay so cangw — she manages the PF_CAN netlink gateway. iconic behaviour, no notes. 💅

👑 Commands 👑

these are the four things she Actually Does. pick one, bestie:

• -A — add a new rule ✨
• -D — delete a rule 🙈
• -F — flush / delete all rules 💀
• -L — list all rules 📋

🫶 Mandatory 🫶

these are not optional, like fr fr, you literally cannot skip these:

• -s <src_dev> — the source netdevice 🎀
• -d <dst_dev> — the destination netdevice 🦋

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💖 OPTIONS 💖

• -X — this is a CAN FD rule 🚗✨
• -t — preserve the src_dev rx timestamp ⏰
• -e — echo sent frames — lowkey recommended on vcanx 🗣️
• -i — allow it to route to the incoming interface 🔁
• -u <uid> — a user defined modification identifier 🏷️
• -l <hops> — limit the number of frame hops / routings 🐇
• -f <filter> — set the CAN filter 🔍
• -m <mod> — set Classical CAN frame modifications 🛠️
• -M <MOD> — set CAN FD frame modifications 🚗🔧
• -x <from_idx>:<to_idx>:<result_idx>:<init_xor_val> — XOR checksum ➗
• -c <from>:<to>:<result>:<init_val>:<xor_val>:<crctab[256]> — CRC8 cs 🧮
• -p <profile>:[<profile_data>] — CRC8 checksum profile & parameters 📐

values are given and expected in hexadecimal values. leading 0s can be omitted, she doesn't care. 💅

🎀 <filter> is a <value><mask> CAN identifier filter:

• <can_id>:<can_mask> — matches when <received_can_id> & mask == can_id & mask ✅
• <can_id>~<can_mask> — matches when <received_can_id> & mask != can_id & mask ❌

🛠️ <mod> is a Classical CAN frame modification instruction, and it's built like this:

<instruction>:<can_frame-elements>:<can_id>.<can_dlc>.<can_data>

• <instruction> — is one of 'AND' 'OR' 'XOR' 'SET'
• <can_frame-elements> — is _one_ or _more_ of 'I'dentifier 'L'ength 'D'ata
• <can_id> — is an u32 value containing the CAN Identifier
• <can_dlc> — is an u8 value containing the data length code in hex (0 .. F)
• <can_data> — is always eight(!) u8 values containing the CAN frames data 👀

🚗 <MOD> is a CAN FD frame modification instruction, and she's built like this:

<instruction>:<canfd_frame-elements>:<can_id>.<flags>.<len>.<can_data>

• <instruction> — is one of 'AND' 'OR' 'XOR' 'SET'
• <canfd_frame-elements> — is _one_ or _more_ of 'I'd 'F'lags 'L'ength 'D'ata
• <can_id> — is an u32 value containing the CAN FD Identifier
• <flags> — is an u8 value containing CAN FD flags (CANFD_BRS, CANFD_ESI)
• <len> — is an u8 value containing the data length in hex (0 .. 40)
• <can_data> — is always 64(!) u8 values containing the CAN FD frames data 🤯

the max. four modifications are performed in the order AND -> OR -> XOR -> SET. that's the pipeline bestie, don't fight it. 🔥

🧚 Supported CRC 8 profiles:

• Profile '1' (1U8) — add one additional u8 value ✨
• Profile '2' (16U8) — add u8 value from table[16] indexed by (data[1] & 0xF) 🌸
• Profile '3' (SFFID_XOR) — add u8 value (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) 🌈

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🔥 EXAMPLES 🔥

the moment you've all been waiting for, the demonstration, the main character moment:

cangw -A -s can0 -d vcan3 -e -f 123:C00007FF -m SET:IL:333.4.1122334455667788

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and that's the whole page bestie!! 🫶 this was cangw 2023.03-1build1, brought to you in December 2025, straight out of the CANGW(1) manual. go route some frames, you absolute icon. 💅✨🎀🦋