srvxdpbpf.h File Reference

Shared per-interface BPF objects for the AF_XDP driver: one XSKMAP plus redirect-filter program plus link per ifindex, shared by every per-queue XSK socket (wired_srvxdp). More...

#include "common/platform/sys/syscall.h"

Go to the source code of this file.

Data Structures
struct	wired_srvxdpbpf
	The three kernel objects backing one interface's redirect filter. More...

Macros
#define	WIRED_SRVXDPBPF_MAP_ENTRIES   64u
	Max XSKMAP entries = max NIC queues servable per interface.

Functions
i64	wired_srvxdpbpf_open (wired_srvxdpbpf *b, u32 ifindex, u16 port, u32 attach_flags)
	Create the XSKMAP (WIRED_SRVXDPBPF_MAP_ENTRIES slots), build and load the redirect-filter program around it (xdpbpf_prog_build, dport == port), and attach it to the interface with a BPF link.
i64	wired_srvxdpbpf_register (wired_srvxdpbpf *b, u32 queue_id, u32 xsk_fd)
	Point the map's queue_id slot at an XSK socket fd, so frames arriving on that NIC queue are redirected to that socket.
void	wired_srvxdpbpf_close (wired_srvxdpbpf *b)
	Close the link, program and map fds in that order (negative fds are skipped) and reset each to -1.

Detailed Description

Shared per-interface BPF objects for the AF_XDP driver: one XSKMAP plus redirect-filter program plus link per ifindex, shared by every per-queue XSK socket (wired_srvxdp).

The kernel allows only one XDP link per interface (a second BPF_LINK_CREATE is -EBUSY), so multi-queue servers open this object once per interface and register each queue's XSK socket into its map; the program already redirects by rx_queue_index.

Function Documentation

wired_srvxdpbpf_close()

void wired_srvxdpbpf_close

(

wired_srvxdpbpf *

b

)

Close the link, program and map fds in that order (negative fds are skipped) and reset each to -1.

Safe to call repeatedly.

Parameters

b	shared BPF objects to tear down

wired_srvxdpbpf_open()

i64 wired_srvxdpbpf_open	(	wired_srvxdpbpf *	b,
		u32	ifindex,
		u16	port,
		u32	attach_flags )

Create the XSKMAP (WIRED_SRVXDPBPF_MAP_ENTRIES slots), build and load the redirect-filter program around it (xdpbpf_prog_build, dport == port), and attach it to the interface with a BPF link.

On any failure, everything already built is closed in reverse order and every fd is left at -1.

Parameters

b	output; all three fds valid on success, -1 on failure
ifindex	network interface to attach to
port	UDP destination port the filter redirects
attach_flags	0 = native XDP, XDP_FLAGS_SKB_MODE(2) = generic/veth

Returns

0 on success, or a negative errno

wired_srvxdpbpf_register()

i64 wired_srvxdpbpf_register	(	wired_srvxdpbpf *	b,
		u32	queue_id,
		u32	xsk_fd )

Point the map's queue_id slot at an XSK socket fd, so frames arriving on that NIC queue are redirected to that socket.

Parameters

b	open shared BPF objects for the socket's interface
queue_id	NIC RX queue index (key into the XSKMAP)
xsk_fd	AF_XDP socket fd bound to that queue

Returns

0 on success, or a negative errno