linux/tools/testing/selftests/bpf/sendmsg4_prog.c
Andrey Ignatov 04b6ab7312 selftests/bpf: Selftest for sys_sendmsg hooks
Add selftest for BPF_CGROUP_UDP4_SENDMSG and BPF_CGROUP_UDP6_SENDMSG
attach types.

Try to sendmsg(2) to specific IP:port and test that:
* source IP is overridden as expected.
* remote IP:port pair is overridden as expected;

Both UDPv4 and UDPv6 are tested.

Output:
  # test_sock_addr.sh 2>/dev/null
  Wait for testing IPv4/IPv6 to become available ... OK
  ... pre-existing test-cases skipped ...
  Test case: sendmsg4: load prog with wrong expected attach type .. [PASS]
  Test case: sendmsg4: attach prog with wrong attach type .. [PASS]
  Test case: sendmsg4: rewrite IP & port (asm) .. [PASS]
  Test case: sendmsg4: rewrite IP & port (C) .. [PASS]
  Test case: sendmsg4: deny call .. [PASS]
  Test case: sendmsg6: load prog with wrong expected attach type .. [PASS]
  Test case: sendmsg6: attach prog with wrong attach type .. [PASS]
  Test case: sendmsg6: rewrite IP & port (asm) .. [PASS]
  Test case: sendmsg6: rewrite IP & port (C) .. [PASS]
  Test case: sendmsg6: IPv4-mapped IPv6 .. [PASS]
  Test case: sendmsg6: deny call .. [PASS]
  Summary: 27 PASSED, 0 FAILED

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-28 17:41:05 +02:00

50 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <linux/stddef.h>
#include <linux/bpf.h>
#include <sys/socket.h>
#include "bpf_helpers.h"
#include "bpf_endian.h"
#define SRC1_IP4 0xAC100001U /* 172.16.0.1 */
#define SRC2_IP4 0x00000000U
#define SRC_REWRITE_IP4 0x7f000004U
#define DST_IP4 0xC0A801FEU /* 192.168.1.254 */
#define DST_REWRITE_IP4 0x7f000001U
#define DST_PORT 4040
#define DST_REWRITE_PORT4 4444
int _version SEC("version") = 1;
SEC("cgroup/sendmsg4")
int sendmsg_v4_prog(struct bpf_sock_addr *ctx)
{
if (ctx->type != SOCK_DGRAM)
return 0;
/* Rewrite source. */
if (ctx->msg_src_ip4 == bpf_htonl(SRC1_IP4) ||
ctx->msg_src_ip4 == bpf_htonl(SRC2_IP4)) {
ctx->msg_src_ip4 = bpf_htonl(SRC_REWRITE_IP4);
} else {
/* Unexpected source. Reject sendmsg. */
return 0;
}
/* Rewrite destination. */
if ((ctx->user_ip4 >> 24) == (bpf_htonl(DST_IP4) >> 24) &&
ctx->user_port == bpf_htons(DST_PORT)) {
ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
} else {
/* Unexpected source. Reject sendmsg. */
return 0;
}
return 1;
}
char _license[] SEC("license") = "GPL";