FreeBSD/Linux Kernel Cross Reference
sys/net/bpf_jitter.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
      * Copyright (C) 2005-2017 Jung-uk Kim <jkim@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     *
     * 1. Redistributions of source code must retain the above copyright
     * notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     * notice, this list of conditions and the following disclaimer in the
     * documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the Politecnico di Torino nor the names of its
     * contributors may be used to endorse or promote products derived from
     * this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #ifdef _KERNEL
    #include "opt_bpf.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/sysctl.h>
    #else
    #include <stdlib.h>
    #include <sys/mman.h>
    #include <sys/param.h>
    #include <sys/types.h>
    #endif
    
    #include <net/bpf.h>
    #include <net/bpf_jitter.h>
    
    static u_int    bpf_jit_accept_all(u_char *, u_int, u_int);
    
    #ifdef _KERNEL
    MALLOC_DEFINE(M_BPFJIT, "BPF_JIT", "BPF JIT compiler");
    
    SYSCTL_NODE(_net, OID_AUTO, bpf_jitter, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
        "BPF JIT compiler");
    int bpf_jitter_enable = 1;
    SYSCTL_INT(_net_bpf_jitter, OID_AUTO, enable, CTLFLAG_RW,
        &bpf_jitter_enable, 0, "enable BPF JIT compiler");
    #endif
    
    bpf_jit_filter *
    bpf_jitter(struct bpf_insn *fp, int nins)
    {
            bpf_jit_filter *filter;
    
            /* Allocate the filter structure. */
    #ifdef _KERNEL
            filter = (struct bpf_jit_filter *)malloc(sizeof(*filter),
                M_BPFJIT, M_NOWAIT);
    #else
            filter = (struct bpf_jit_filter *)malloc(sizeof(*filter));
    #endif
            if (filter == NULL)
                    return (NULL);
    
            /* No filter means accept all. */
            if (fp == NULL || nins == 0) {
                    filter->func = bpf_jit_accept_all;
                    return (filter);
            }
    
            /* Create the binary. */
            if ((filter->func = bpf_jit_compile(fp, nins, &filter->size)) == NULL) {
    #ifdef _KERNEL
                    free(filter, M_BPFJIT);
    #else
                    free(filter);
    #endif
                    return (NULL);
            }
    
            return (filter);
    }
   
   void
   bpf_destroy_jit_filter(bpf_jit_filter *filter)
   {
   
   #ifdef _KERNEL
           if (filter->func != bpf_jit_accept_all)
                   free(filter->func, M_BPFJIT);
           free(filter, M_BPFJIT);
   #else
           if (filter->func != bpf_jit_accept_all)
                   munmap(filter->func, filter->size);
           free(filter);
   #endif
   }
   
   static u_int
   bpf_jit_accept_all(__unused u_char *p, __unused u_int wirelen,
       __unused u_int buflen)
   {
   
           return ((u_int)-1);
   }

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