LXR linux/tools/testing/selftests/bpf/progs/sockopt

   1// SPDX-License-Identifier: GPL-2.0
   2#include <netinet/in.h>
   3#include <linux/bpf.h>
   4#include <bpf/bpf_helpers.h>
   5
   6char _license[] SEC("license") = "GPL";
   7__u32 _version SEC("version") = 1;
   8
   9SEC("cgroup/getsockopt/child")
  10int _getsockopt_child(struct bpf_sockopt *ctx)
  11{
  12        __u8 *optval_end = ctx->optval_end;
  13        __u8 *optval = ctx->optval;
  14
  15        if (ctx->level != SOL_IP || ctx->optname != IP_TOS)
  16                return 1;
  17
  18        if (optval + 1 > optval_end)
  19                return 0; /* EPERM, bounds check */
  20
  21        if (optval[0] != 0x80)
  22                return 0; /* EPERM, unexpected optval from the kernel */
  23
  24        ctx->retval = 0; /* Reset system call return value to zero */
  25
  26        optval[0] = 0x90;
  27        ctx->optlen = 1;
  28
  29        return 1;
  30}
  31
  32SEC("cgroup/getsockopt/parent")
  33int _getsockopt_parent(struct bpf_sockopt *ctx)
  34{
  35        __u8 *optval_end = ctx->optval_end;
  36        __u8 *optval = ctx->optval;
  37
  38        if (ctx->level != SOL_IP || ctx->optname != IP_TOS)
  39                return 1;
  40
  41        if (optval + 1 > optval_end)
  42                return 0; /* EPERM, bounds check */
  43
  44        if (optval[0] != 0x90)
  45                return 0; /* EPERM, unexpected optval from the kernel */
  46
  47        ctx->retval = 0; /* Reset system call return value to zero */
  48
  49        optval[0] = 0xA0;
  50        ctx->optlen = 1;
  51
  52        return 1;
  53}
  54
  55SEC("cgroup/setsockopt")
  56int _setsockopt(struct bpf_sockopt *ctx)
  57{
  58        __u8 *optval_end = ctx->optval_end;
  59        __u8 *optval = ctx->optval;
  60
  61        if (ctx->level != SOL_IP || ctx->optname != IP_TOS)
  62                return 1;
  63
  64        if (optval + 1 > optval_end)
  65                return 0; /* EPERM, bounds check */
  66
  67        optval[0] += 0x10;
  68        ctx->optlen = 1;
  69
  70        return 1;
  71}
  72