rpcb_v4_register(9)

🌸 NAME 🌸

okay so bestie, welcome to the Kernel API Manual page for rpcb_v4_register(9) — and it's literally about setting or unsetting a port registration with the local rpcbind. no cap, that's the whole vibe: rpcb_v4_register — set or unset a port registration with the local rpcbind. 💅

✨ SYNOPSIS ✨

int rpcb_v4_register (struct net *net , const u32 program , const u32 version , const struct sockaddr *address , const char *netid );

🫶 ARGUMENTS 🫶

• net — the target network namespace. yes, that's the whole namespace situation.
• program — RPC program number of service to (un)register. 🎀
• version — RPC version number of service to (un)register. ⭐
• address — address family, IP address, and port to (un)register. the whole little address package.
• netid — netid of transport protocol to (un)register. transport tea. 🍓

💖 DESCRIPTION 💖

so here's the tea: this function returns zero if the registration request was dispatched successfully and the rpcbind daemon returned success. otherwise? it returns an errno value that reflects the nature of the error — like the request could not be dispatched, it timed out, or rpcbind returned an error. 😭

RPC services invoke this function to advertise their contact information via the system's rpcbind daemon. they invoke this function once for each [program, version, address, netid] tuple they wish to advertise. one tuple, one call — that's the vibe. ✨

callers may also unregister RPC services that are registered at a specific address by setting the port number in address to zero. they may unregister all registered protocol families at once for a service by passing a NULL address argument. and if netid is "" then all netids for [program, version, address] are unregistered. poof, gone. 🫧

this function uses rpcbind protocol version 4 to contact the local rpcbind daemon. the local rpcbind daemon must support version 4 of the rpcbind protocol in order for these functions to register a service successfully. no v4? no successful registration, bestie. 💀

supported netids include "udp" and "tcp" for UDP and TCP over IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6, respectively. cute lil protocol family menu. 🍓

the contents of address determine the address family and the port to be registered. the usual practice is to pass INADDR_ANY as the raw address, but specifying a non-zero address is also supported by this API if the caller wishes to advertise an RPC service on a specific network interface. main character interface energy. 👑

note bestie: passing in INADDR_ANY does not create the same service registration as IN6ADDR_ANY. the former advertises an RPC service on any IPv4 address, but not on IPv6. the latter advertises the service on all IPv4 and IPv6 addresses. so yes, they are different — do not conflate them. 🙈

🌈 SEE ALSO 🌈

• Kernel file ./net/sunrpc/rpcb_clnt.c rpcb_register(9), rpcb_getport_async(9) — go read these, bestie 🦋

and that's the page, bestie. source/version says ./net/sunrpc, date says October 2026, and the page itself is rpcb_v4_register(9). mwah, go register responsibly. 💖🎀