udp_poll(9)

💖 NAME 💖

okay so bestie, this is udp_poll(9) from the Kernel API Manual, and it's here to wait for a UDP event ✨ literally that's the whole vibe 👑

✨ SYNOPSIS ✨

__poll_t udp_poll (struct file *file , struct socket *sock , poll_table *wait );

🫶 ARGUMENTS 🫶

• file — the file struct 🗂️ like, that file struct.
• sock — the socket 🧦 yep, that socket.
• wait — the poll table 💫 the waiting-table situation.

🌸 DESCRIPTION 🌸

so this is the same as datagram poll, except for the special case of blocking sockets 🫶

here's the tea: if an application is using a blocking fd and a packet with a checksum error is in the queue, then it could get a return from select indicating data is available — but then it blocks when reading it 😭 not the plot twist we wanted.

so there's special case code added to work around these arguably broken applications 💅 periodt.

ngl, that's the whole reason this special case exists — those apps are arguably broken, and this is the workaround 🎀

👑 SEE ALSO 👑

Kernel file ./net/ipv4/udp.c has the friend group: udp_lib_get_port(9), udp4_lib_lookup1(9), udp4_hwcsum(9), and first_packet_length(9) 🌈 go say hi 👋

mwah 💖 this little page lives in ./net/ipv4, dated October 2026, and it's literally udp_poll(9) — bye bestie! 🎀