sys/net/bpf_jitter.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
   5  * Copyright (C) 2005-2017 Jung-uk Kim <jkim@FreeBSD.org>
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  * notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  * notice, this list of conditions and the following disclaimer in the
  16  * documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the Politecnico di Torino nor the names of its
  18  * contributors may be used to endorse or promote products derived from
  19  * this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35 #ifdef _KERNEL
  36 #include "opt_bpf.h"
  37
  38 #include <sys/param.h>
  39 #include <sys/kernel.h>
  40 #include <sys/malloc.h>
  41 #include <sys/mbuf.h>
  42 #include <sys/sysctl.h>
  43 #else
  44 #include <stdlib.h>
  45 #include <sys/mman.h>
  46 #include <sys/param.h>
  47 #include <sys/types.h>
  48 #endif
  49
  50 #include <net/bpf.h>
  51 #include <net/bpf_jitter.h>
  52
  53 static u_int    bpf_jit_accept_all(u_char *, u_int, u_int);
  54
  55 #ifdef _KERNEL
  56 MALLOC_DEFINE(M_BPFJIT, "BPF_JIT", "BPF JIT compiler");
  57
  58 SYSCTL_NODE(_net, OID_AUTO, bpf_jitter, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
  59     "BPF JIT compiler");
  60 int bpf_jitter_enable = 1;
  61 SYSCTL_INT(_net_bpf_jitter, OID_AUTO, enable, CTLFLAG_RW,
  62     &bpf_jitter_enable, 0, "enable BPF JIT compiler");
  63 #endif
  64
  65 bpf_jit_filter *
  66 bpf_jitter(struct bpf_insn *fp, int nins)
  67 {
  68         bpf_jit_filter *filter;
  69
  70         /* Allocate the filter structure. */
  71 #ifdef _KERNEL
  72         filter = (struct bpf_jit_filter *)malloc(sizeof(*filter),
  73             M_BPFJIT, M_NOWAIT);
  74 #else
  75         filter = (struct bpf_jit_filter *)malloc(sizeof(*filter));
  76 #endif
  77         if (filter == NULL)
  78                 return (NULL);
  79
  80         /* No filter means accept all. */
  81         if (fp == NULL || nins == 0) {
  82                 filter->func = bpf_jit_accept_all;
  83                 return (filter);
  84         }
  85
  86         /* Create the binary. */
  87         if ((filter->func = bpf_jit_compile(fp, nins, &filter->size)) == NULL) {
  88 #ifdef _KERNEL
  89                 free(filter, M_BPFJIT);
  90 #else
  91                 free(filter);
  92 #endif
  93                 return (NULL);
  94         }
  95
  96         return (filter);
  97 }
  98
  99 void
 100 bpf_destroy_jit_filter(bpf_jit_filter *filter)
 101 {
 102
 103 #ifdef _KERNEL
 104         if (filter->func != bpf_jit_accept_all)
 105                 free(filter->func, M_BPFJIT);
 106         free(filter, M_BPFJIT);
 107 #else
 108         if (filter->func != bpf_jit_accept_all)
 109                 munmap(filter->func, filter->size);
 110         free(filter);
 111 #endif
 112 }
 113
 114 static u_int
 115 bpf_jit_accept_all(__unused u_char *p, __unused u_int wirelen,
 116     __unused u_int buflen)
 117 {
 118
 119         return ((u_int)-1);
 120 }