NetBSD/usr.bin/netstat/bpf.c
ozaki-r 1d675d5a3a netstat: strengthen against kernel changes
netstat uses sysctlbyname to get counter data from the kernel.
sysctlbyname fails with ENOMEM if actual counter data in the kernel is
larger than a passed buffer.  netstat just skips showing counters of a
category if sysctlbyname fails, so if we added new counters of the
category to the kernel, nestat shows nothing for the category.

Fortunately sysctlbyname fills data as much as possible even if a passed
buffer is short.  So we can allow netstat to show the filled data anyway
if sysctlbyname fails with ENOMEM.

Note that this backcompat mechanism works only if new counters are
appended, and doesn't work if new counters are inserted into the middle
or counters are moved.
2020-08-28 07:23:48 +00:00

178 lines
4.7 KiB
C

/* $NetBSD: bpf.c,v 1.15 2020/08/28 07:23:48 ozaki-r Exp $ */
/*
* Copyright (c) 2005 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Rui Paulo.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <err.h>
#include <errno.h>
#include <fcntl.h>
#include <kvm.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <net/bpfdesc.h>
#include <net/bpf.h>
#include "netstat.h"
#include "prog_ops.h"
void
bpf_stats(void)
{
struct bpf_stat bpf_s;
size_t len = sizeof(bpf_s);
if (use_sysctl) {
if (prog_sysctlbyname("net.bpf.stats", &bpf_s, &len, NULL, 0) == -1 &&
errno != ENOMEM)
err(1, "net.bpf.stats");
printf("bpf:\n");
printf("\t%" PRIu64 " total packets received\n",
bpf_s.bs_recv);
printf("\t%" PRIu64 " total packets captured\n",
bpf_s.bs_capt);
printf("\t%" PRIu64 " total packets dropped\n",
bpf_s.bs_drop);
} else {
warnx("BPF stats not available via KVM.");
}
}
void
bpf_dump(const char *bpfif)
{
struct bpf_d_ext *dpe;
if (use_sysctl) {
int name[CTL_MAXNAME], rc;
size_t i, sz, szproc;
u_int namelen;
void *v;
struct kinfo_proc2 p;
/* adapted from sockstat.c by Andrew Brown */
sz = CTL_MAXNAME;
if (prog_sysctlnametomib("net.bpf.peers", &name[0], &sz) == -1)
err(1, "sysctlnametomib: net.bpf.peers");
namelen = sz;
name[namelen++] = sizeof(*dpe);
name[namelen++] = INT_MAX;
v = NULL;
sz = 0;
do {
rc = prog_sysctl(&name[0], namelen,
v, &sz, NULL, 0);
if (rc == -1 && errno != ENOMEM)
err(1, "sysctl: net.bpf.peers");
if (rc == -1 && v != NULL) {
free(v);
v = NULL;
}
if (v == NULL) {
v = malloc(sz);
rc = -1;
}
if (v == NULL)
err(1, "malloc");
} while (rc == -1);
dpe = v;
puts("Active BPF peers\nPID\tInt\tRecv Drop Capt" \
" Flags Bufsize Comm");
#define BPFEXT(entry) dpe->entry
for (i = 0; i < (sz / sizeof(*dpe)); i++, dpe++) {
if (bpfif &&
strncmp(BPFEXT(bde_ifname), bpfif, IFNAMSIZ))
continue;
printf("%-7d ", BPFEXT(bde_pid));
printf("%-7s ",
(BPFEXT(bde_ifname)[0] == '\0') ? "-" :
BPFEXT(bde_ifname));
printf("%-8" PRIu64 " %-8" PRIu64 " %-8" PRIu64 " ",
BPFEXT(bde_rcount), BPFEXT(bde_dcount),
BPFEXT(bde_ccount));
switch (BPFEXT(bde_state)) {
case BPF_IDLE:
printf("I");
break;
case BPF_WAITING:
printf("W");
break;
case BPF_TIMED_OUT:
printf("T");
break;
default:
printf("-");
break;
}
printf("%c", BPFEXT(bde_promisc) ? 'P' : '-');
printf("%c", BPFEXT(bde_immediate) ? 'R' : '-');
printf("%c", (BPFEXT(bde_direction) == BPF_D_IN) ? '-'
: (BPFEXT(bde_direction) == BPF_D_OUT) ? 'O' : 'S');
printf("%c", BPFEXT(bde_hdrcmplt) ? 'H' : '-');
printf(" %-8d ", BPFEXT(bde_bufsize));
szproc = sizeof(p);
namelen = 0;
name[namelen++] = CTL_KERN;
name[namelen++] = KERN_PROC2;
name[namelen++] = KERN_PROC_PID;
name[namelen++] = BPFEXT(bde_pid);
name[namelen++] = szproc;
name[namelen++] = 1;
if (prog_sysctl(&name[0], namelen, &p, &szproc,
NULL, 0) == -1)
printf("-\n");
else
printf("%s\n", p.p_comm);
#undef BPFEXT
}
free(v);
} else {
/* XXX */
errx(1, "bpf_dump not implemented using kvm");
}
}