tools/testing/selftests/bpf/progs/ksock_lsm.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2026 Isovalent */

#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_endian.h>
#include "bpf_tracing_net.h"
#include "ksock_common.h"

char send_data[32] = "hello from bpf ksock";

__be32 ipv4_remote;
__u16 remote_port;
int target_pid;
int send_ret = -1;

SEC("syscall")
int ksock_setup(void *ctx)
{
	struct bpf_ksock_create_opts create_opts = {};
	union bpf_ksock_addr addr = {};
	struct bpf_ksock *ks;
	int err = 0;

	create_opts.family = AF_INET;
	create_opts.type = SOCK_DGRAM;
	create_opts.protocol = IPPROTO_UDP;

	ks = bpf_ksock_create(&create_opts, sizeof(create_opts), &err);
	if (!ks)
		return err;

	addr.sin.sin_family = AF_INET;
	addr.sin.sin_port = bpf_htons(remote_port);
	addr.sin.sin_addr.s_addr = ipv4_remote;

	err = bpf_ksock_connect(ks, &addr, sizeof(addr));
	if (err) {
		bpf_ksock_release(ks);
		return err;
	}

	err = ksock_ctx_insert(ks);
	if (err && err != -EEXIST)
		return err;
	return 0;
}

SEC("lsm.s/socket_bind")
int BPF_PROG(ksock_socket_bind, struct socket *sock, struct sockaddr *address,
	     int addrlen, int ret)
{
	struct bpf_ksock *ks;
	u32 pid = bpf_get_current_pid_tgid() >> 32;

	if (ret || pid != target_pid)
		return ret;

	ks = ksock_ctx_get();
	if (!ks) {
		send_ret = -ENOENT;
		return ret;
	}

	send_ret = bpf_ksock_send(ks, send_data, sizeof(send_data));
	bpf_ksock_release(ks);

	return ret;
}

char __license[] SEC("license") = "GPL";