csum_tcpudp_nofold(9)

✨ NAME ✨

welcome to the Kernel API Manual moment for csum_tcpudp_nofold(9), bestie 💖 this function literally computes an IPv4 pseudo header checksum, and that's the whole assignment. slay.

🦋 SYNOPSIS 🦋

__wsum csum_tcpudp_nofold (__be32 saddr , __be32 daddr , __u32 len ,
__u8 proto , __wsum sum );

🎀 ARGUMENTS 🎀

• saddr — source address 👑
• daddr — destination address ✨
• len — length of packet 🌸
• proto — ip protocol of packet 🦋
• sum — initial sum to be added in (32bit unfolded) 💅

💜 RETURN 💜

it gives you the pseudo header checksum for the input data, and the result is 32bit unfolded — periodt. 🫶

🌈 SEE ALSO 🌈

the Kernel file ./arch/x86/include/asm/checksum_64.h is where the lore lives, and these besties are linked:

• csum_fold(9)
• ip_fast_csum(9)
• csum_tcpudp_magic(9)
• csum_partial(9)
• ip_compute_csum(9)
• csum_ipv6_magic(9)

mwah 💋 sourced from ./arch/x86/include/asm, dated October 2026, and yes bestie this page is csum_tcpudp_nofold(9) — bye, love u 🫶💖