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Helper function bpf_sk_lookup_udp

v4.20

Definition

Copyright (c) 2015 The Libbpf Authors. All rights reserved.

Look for UDP socket matching tuple, optionally in a child network namespace netns. The return value must be checked, and if non-NULL, released via bpf_sk_release().

The ctx should point to the context of the program, such as the skb or socket (depending on the hook in use). This is used to determine the base network namespace for the lookup.

tuple_size must be one of:

sizeof(tuple->ipv4)

    Look for an IPv4 socket.

sizeof(tuple->ipv6)

    Look for an IPv6 socket.

If the netns is a negative signed 32-bit integer, then the socket lookup table in the netns associated with the ctx will be used. For the TC hooks, this is the netns of the device in the skb. For socket hooks, this is the netns of the socket. If netns is any other signed 32-bit value greater than or equal to zero then it specifies the ID of the netns relative to the netns associated with the ctx. netns values beyond the range of 32-bit integers are reserved for future use.

All values for flags are reserved for future usage, and must be left at zero.

This helper is available only if the kernel was compiled with CONFIG_NET configuration option.

Returns

Pointer to struct bpf_sock, or NULL in case of failure. For sockets with reuseport option, the struct bpf_sock result is from reuse->socks[] using the hash of the tuple.

static struct bpf_sock *(* const bpf_sk_lookup_udp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 85;

Usage

Docs could be improved

This part of the docs is incomplete, contributions are very welcome

Program types

This helper call can be used in the following program types:

Example

Docs could be improved

This part of the docs is incomplete, contributions are very welcome