lowpan_header_compress(9)

💅 lowpan_header_compress(9)

okay so bestie, welcome to the Kernel API Manual ✨ this one's all about lowpan_header_compress, and honestly? it's giving glow-up energy for packets 👑

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🌸 NAME

lowpan_header_compress — replaces the IPv6 header with a 6LoWPAN header 🎀

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✨ SYNOPSIS

int lowpan_header_compress (struct sk_buff *skb , const struct
       net_device *dev , const void *daddr , const void *saddr );

like, that's the whole signature, no cap 💅

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🦋 ARGUMENTS

• skb — the buffer that's gonna get manipulated 🫶 (yes, that's the buffer being done dirty, it's fine, it consented)
• dev — the lowpan net device pointer 🌈
• daddr — the destination lladdr of the mac header, and it's the one used for the compression methods 💖
• saddr — the source lladdr of the mac header, also used for the compression methods ⭐

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💀 DESCRIPTION

okay so here's the tea 🍓 — this function replaces the IPv6 header with the IPHC 6LoWPAN header. and which IPv6 header, you ask? the one that should be pointed at by skb->data and skb_network_header. iconic behavior, truly 👑

but listen, bestie, there are rules 🙈 the caller needs to be sure of two things:

1. the sk buffer is not shared 😭
2. it has at least a headroom which is smaller or equal to LOWPAN_IPHC_MAX_HEADER_LEN — which, and I cannot stress this enough, is the IPHC "more bytes than IPv6 header" at worst case 💀

fr fr, do the vibe check on your buffer before you call this. the worst-case sizing is not a suggestion, it's the whole point 🧚

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👑 SEE ALSO

• Kernel file ./include/net/6lowpan.h
• lowpan_fetch_skb(9)
• lowpan_header_decompress(9)

iykyk, go read the friends too 💜

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and that's the whole page, bestie 🎀 huge thanks to ./include/net for dropping this one in October 2026 — mwah, slay, periodt 💅✨