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/*
*------------------------------------------------------------------
* Copyright (c) 2023 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*------------------------------------------------------------------
*/
#include <vlib/vlib.h>
#include <bpf_trace_filter/bpf_trace_filter.h>
clib_error_t *
bpf_trace_filter_init (vlib_main_t *vm)
{
bpf_trace_filter_main_t *btm = &bpf_trace_filter_main;
btm->pcap = pcap_open_dead (DLT_EN10MB, 65535);
return 0;
}
int vnet_is_packet_traced (vlib_buffer_t *b, u32 classify_table_index,
int func);
u8 *
format_bpf_trace_filter (u8 *s, va_list *a)
{
bpf_trace_filter_main_t *btm = va_arg (*a, bpf_trace_filter_main_t *);
struct bpf_insn *insn;
if (!btm->prog_set)
return format (s, "bpf trace filter is not set");
insn = btm->prog.bf_insns;
for (int i = 0; i < btm->prog.bf_len; insn++, i++)
s = format (s, "%s\n", bpf_image (insn, i));
return s;
}
clib_error_t *
bpf_trace_filter_set_unset (const char *bpf_expr, u8 is_del, u8 optimize)
{
bpf_trace_filter_main_t *btm = &bpf_trace_filter_main;
if (is_del)
{
if (btm->prog_set)
{
btm->prog_set = 0;
pcap_freecode (&btm->prog);
}
}
else if (bpf_expr)
{
if (btm->prog_set)
pcap_freecode (&btm->prog);
btm->prog_set = 0;
if (pcap_compile (btm->pcap, &btm->prog, (char *) bpf_expr, optimize,
PCAP_NETMASK_UNKNOWN))
{
return clib_error_return (0, "Failed pcap_compile of %s", bpf_expr);
}
btm->prog_set = 1;
}
return 0;
};
int
bpf_is_packet_traced (vlib_buffer_t *b, u32 classify_table_index, int func)
{
bpf_trace_filter_main_t *bfm = &bpf_trace_filter_main;
struct pcap_pkthdr phdr = { 0 };
int res;
int res1;
if (classify_table_index != ~0 &&
(res1 = vnet_is_packet_traced (b, classify_table_index, 0)) != 1)
return res1;
if (!bfm->prog_set)
return 1;
phdr.caplen = b->current_length;
phdr.len = b->current_length;
res = pcap_offline_filter (&bfm->prog, &phdr, vlib_buffer_get_current (b));
return res != 0;
}
VLIB_REGISTER_TRACE_FILTER_FUNCTION (bpf_trace_filter_fn, static) = {
.name = "bpf_trace_filter",
.description = "bpf based trace filter",
.priority = 10,
.function = bpf_is_packet_traced
};
VLIB_INIT_FUNCTION (bpf_trace_filter_init);
bpf_trace_filter_main_t bpf_trace_filter_main;
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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