Trying to wrap my head around some of the snmpd code I found this pearl
that appears to do nothing more than warm up the room.
OK?
martijn@
Index: Makefile
===================================================================
RCS file: /cvs/src/usr.sbin/snmpd/Makefile,v
retrieving revision 1.16
diff -u -p -r1.16 Makefile
--- Makefile 11 May 2019 17:46:02 -0000 1.16
+++ Makefile 22 Jan 2020 09:50:51 -0000
@@ -3,7 +3,7 @@
PROG= snmpd
MAN= snmpd.8 snmpd.conf.5
SRCS= parse.y log.c control.c snmpe.c \
- mps.c trap.c mib.c smi.c kroute.c snmpd.c timer.c \
+ mps.c trap.c mib.c smi.c kroute.c snmpd.c \
pf.c proc.c usm.c agentx.c traphandler.c util.c
LDADD= -levent -lutil -lkvm -lcrypto
Index: snmpd.h
===================================================================
RCS file: /cvs/src/usr.sbin/snmpd/snmpd.h,v
retrieving revision 1.86
diff -u -p -r1.86 snmpd.h
--- snmpd.h 2 Jan 2020 10:55:53 -0000 1.86
+++ snmpd.h 22 Jan 2020 09:50:51 -0000
@@ -745,9 +745,6 @@ unsigned int smi_application(struct ber
void smi_debug_elements(struct ber_element *);
char *smi_print_element(struct ber_element *);
-/* timer.c */
-void timer_init(void);
-
/* snmpd.c */
int snmpd_socket_af(struct sockaddr_storage *, in_port_t, int);
u_long snmpd_engine_time(void);
Index: snmpe.c
===================================================================
RCS file: /cvs/src/usr.sbin/snmpd/snmpe.c,v
retrieving revision 1.60
diff -u -p -r1.60 snmpe.c
--- snmpe.c 24 Oct 2019 12:39:27 -0000 1.60
+++ snmpe.c 22 Jan 2020 09:50:51 -0000
@@ -103,7 +103,6 @@ snmpe_init(struct privsep *ps, struct pr
kr_init();
trap_init();
- timer_init();
usm_generate_keys();
/* listen for incoming SNMP UDP/TCP messages */
Index: timer.c
===================================================================
RCS file: timer.c
diff -N timer.c
--- timer.c 28 Oct 2016 08:01:53 -0000 1.7
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,169 +0,0 @@
-/* $OpenBSD: timer.c,v 1.7 2016/10/28 08:01:53 rzalamena Exp $ */
-
-/*
- * Copyright (c) 2008 Reyk Floeter <[email protected]>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-#include <sys/queue.h>
-#include <sys/types.h>
-#include <sys/time.h>
-#include <sys/sched.h>
-#include <sys/socket.h>
-#include <sys/sysctl.h>
-
-#include <net/if.h>
-#include <net/if_types.h>
-#include <netinet/in.h>
-#include <netinet/ip.h>
-#include <netinet/ip_var.h>
-#include <arpa/inet.h>
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <errno.h>
-#include <event.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-#include <pwd.h>
-
-#include "snmpd.h"
-#include "mib.h"
-
-void timer_cpu(int, short, void *);
-int percentages(int, int64_t *, int64_t *, int64_t *, int64_t *);
-
-static int64_t **cp_time;
-static int64_t **cp_old;
-static int64_t **cp_diff;
-struct event cpu_ev;
-
-void
-timer_cpu(int fd, short event, void *arg)
-{
- struct event *ev = (struct event *)arg;
- struct timeval tv = { 60, 0 }; /* every 60 seconds */
- int mib[3] = { CTL_KERN, KERN_CPTIME2, 0 }, n;
- size_t len;
- int64_t *cptime2;
-
- len = CPUSTATES * sizeof(int64_t);
- for (n = 0; n < snmpd_env->sc_ncpu; n++) {
- mib[2] = n;
- cptime2 = snmpd_env->sc_cpustates + (CPUSTATES * n);
- if (sysctl(mib, 3, cp_time[n], &len, NULL, 0) == -1)
- continue;
- (void)percentages(CPUSTATES, cptime2, cp_time[n],
- cp_old[n], cp_diff[n]);
-#ifdef DEBUG
- log_debug("timer_cpu: cpu%d %lld%% idle in %llds", n,
- (cptime2[CP_IDLE] > 1000 ?
- 1000 : (cptime2[CP_IDLE] / 10)), (long long) tv.tv_sec);
-#endif
- }
-
- evtimer_add(ev, &tv);
-}
-
-void
-timer_init(void)
-{
- int mib[] = { CTL_HW, HW_NCPU }, i;
- size_t len;
-
- len = sizeof(snmpd_env->sc_ncpu);
- if (sysctl(mib, 2, &snmpd_env->sc_ncpu, &len, NULL, 0) == -1)
- fatal("sysctl");
-
- snmpd_env->sc_cpustates = calloc(snmpd_env->sc_ncpu,
- CPUSTATES * sizeof(int64_t));
- cp_time = calloc(snmpd_env->sc_ncpu, sizeof(int64_t *));
- cp_old = calloc(snmpd_env->sc_ncpu, sizeof(int64_t *));
- cp_diff = calloc(snmpd_env->sc_ncpu, sizeof(int64_t *));
- if (snmpd_env->sc_cpustates == NULL ||
- cp_time == NULL || cp_old == NULL || cp_diff == NULL)
- fatal("calloc");
- for (i = 0; i < snmpd_env->sc_ncpu; i++) {
- cp_time[i] = calloc(CPUSTATES, sizeof(int64_t));
- cp_old[i] = calloc(CPUSTATES, sizeof(int64_t));
- cp_diff[i] = calloc(CPUSTATES, sizeof(int64_t));
- if (cp_time[i] == NULL || cp_old[i] == NULL ||
- cp_diff[i] == NULL)
- fatal("calloc");
- }
-
- evtimer_set(&cpu_ev, timer_cpu, &cpu_ev);
- timer_cpu(0, EV_TIMEOUT, &cpu_ev);
-}
-
-/*
- * percentages() function to calculate CPU utilization.
- * Source code derived from the top(1) utility:
- *
- * Copyright (c) 1984, 1989, William LeFebvre, Rice University
- * Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
- *
- * 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 AUTHOR ``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 AUTHOR OR HIS EMPLOYER 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.
- */
-int
-percentages(int cnt, int64_t *out, int64_t *new, int64_t *old, int64_t *diffs)
-{
- int64_t change, total_change, *dp, half_total;
- int i;
-
- /* initialization */
- total_change = 0;
- dp = diffs;
-
- /* calculate changes for each state and the overall change */
- for (i = 0; i < cnt; i++) {
- if ((change = *new - *old) < 0) {
- /* this only happens when the counter wraps */
- change = (*new - *old);
- }
- total_change += (*dp++ = change);
- *old++ = *new++;
- }
-
- /* avoid divide by zero potential */
- if (total_change == 0)
- total_change = 1;
-
- /* calculate percentages based on overall change, rounding up */
- half_total = total_change / 2l;
- for (i = 0; i < cnt; i++)
- *out++ = ((*diffs++ * 1000 + half_total) / total_change);
-
- /* return the total in case the caller wants to use it */
- return (total_change);
-}
