Commit 5feff0eb authored by Alessandro Rubini's avatar Alessandro Rubini Committed by Adam Wujek

net: mini snmp v1 implementation

The "community" string is public. We have tree items only: the host
name, the date and uptime.

The code is designed to make it simple any addition. But we only have
snmpget support, not snmpwak (i.e. "get next" query).

This is run on an host build (CONFIG_HOST_PROCESS) where the time and
date are not related to the real world:

   # snmpget -v 1 -c public 192.168.16.1 .1.3.6.1.2.1.1.5.0
   SNMPv2-MIB::sysName.0 = STRING: wrc
   # snmpget -v 1 -c public 192.168.16.1 .1.3.6.1.2.1.25.1.2.0
   HOST-RESOURCES-MIB::hrSystemDate.0 = STRING: 1970-0-1,19:52:34.0
   # snmpget -v 1 -c public 192.168.16.1 .1.3.6.1.2.1.25.1.2.0
   HOST-RESOURCES-MIB::hrSystemDate.0 = STRING: 1970-0-1,19:53:2.0
   # snmpget -v 1 -c public 192.168.16.1 .1.3.6.1.2.1.25.1.1.0
   [...] hrSystemUptime.0 = Timeticks: (94193300) 10 days, 21:38:53.00
Signed-off-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
parent 0e611221
......@@ -367,6 +367,11 @@ config FAKE_TEMPERATURES
The option adds also a "faketemp" command, used to set
the fake temperatures: e.g. "faketemp 120 -10 50"
config SNMP
depends on IP
default y
boolean "Mini SNMP responder"
config VLAN
depends on DEVELOPER
boolean "Filter and rx/tx frames in a VLAN (as opposed to untagged)"
......
......@@ -9,3 +9,4 @@ obj-$(CONFIG_WR_NODE) += lib/net.o
obj-$(CONFIG_IP) += lib/ipv4.o lib/arp.o lib/icmp.o lib/udp.o lib/bootp.o
obj-$(CONFIG_SYSLOG) += lib/syslog.o
obj-$(CONFIG_LATENCY_PROBE) += lib/latency.o
obj-$(CONFIG_SNMP) += lib/snmp.o
/*
* This work is part of the White Rabbit project
*
* Copyright (C) 2016 GSI (www.gsi.de)
* Author: Alessandro Rubini <a.rubini@gsi.de>
*
* Released according to the GNU GPL, version 2 or any later version.
*/
#include <string.h>
#include <wrpc.h>
#include "endpoint.h"
#include "ipv4.h"
#include "ptpd_netif.h"
#include "pps_gen.h"
#include "hw/memlayout.h"
#include "hw/etherbone-config.h"
#ifndef htons
#define htons(x) x
#endif
static uint8_t __snmp_queue[256];
static struct wrpc_socket __static_snmp_socket = {
.queue.buff = __snmp_queue,
.queue.size = sizeof(__snmp_queue),
};
static struct wrpc_socket *snmp_socket;
static void snmp_init(void)
{
/* Use UDP engine activated by function arguments */
snmp_socket = ptpd_netif_create_socket(&__static_snmp_socket, NULL,
PTPD_SOCK_UDP, 161 /* snmp */);
}
/* These fill the actual information, returning the lenght */
static int fill_name(uint8_t *buf)
{
strcpy((void *)(buf + 2), "wrc");
buf[1] = strlen((void *)(buf + 2));
buf[0] = 0x04; /* string */
return 2 + buf[1];
}
static int fill_tics(uint8_t *buf)
{
uint32_t tics = htonl(timer_get_tics() / 10); /* hundredths... bah! */
memcpy(buf + 2, &tics, sizeof(tics));
buf[1] = sizeof(tics);
buf[0] = 0x43; /* who knows... */
return 2 + sizeof(tics);
}
static int fill_date(uint8_t *buf)
{
uint64_t secs;
char *datestr;
shw_pps_gen_get_time(&secs, NULL);
datestr = format_time(secs, TIME_FORMAT_SNMP);
memcpy((void *)(buf + 2), datestr, 12);
buf[1] = 8; /* size is hardwired. See mib document or prev. commit */
buf[0] = 0x04; /* string! (one more f word entering the repo... */
return 2 + buf[1];
}
static uint8_t oid_name[] = {0x2B,0x06,0x01,0x02,0x01,0x01,0x05,0x00};
static uint8_t oid_tics[] = {0x2B,0x06,0x01,0x02,0x01,0x19,0x01,0x01,0x00};
static uint8_t oid_date[] = {0x2B,0x06,0x01,0x02,0x01,0x19,0x01,0x02,0x00};
struct snmp_oid {
uint8_t *oid_match;
int oid_len;
int (*fill)(uint8_t *buf);
};
static struct snmp_oid oid_array[] = {
{ oid_name, sizeof(oid_name), fill_name},
{ oid_tics, sizeof(oid_tics), fill_tics},
{ oid_date, sizeof(oid_date), fill_date},
{ 0, }
};
/*
* Perverse... snmpwalk does getnext anyways. Let's support snmpget only
*
* We support the following ones:
* RFC1213-MIB::sysName.0 (string) .1.3.6.1.2.1.1.5.0
* HOST-RESOURCES-MIB::hrSystemUptime.0 (ticks) .1.3.6.1.2.1.25.1.1.0
* HOST-RESOURCES-MIB::hrSystemDate.0 (string) .1.3.6.1.2.1.25.1.2.0
*
* The request for sysname is like this (-c public):
* 30 29 sequence of 0x29
* 02 01 00 int: snmp version 1 (0x00)
* 04 06 70 75 62 6C 69 63 string of 6: "public"
* A0 1C get request of 0x1c
* 02 04 27 05 36 A9 int of 4: request ID
* 02 01 00 int of 1: error
* 02 01 00 int of 1: error
* 30 0E sequence of 0x0e
* 30 0C sequence of 0x0c
* 06 08 2B 06 01 02 01 01 05 00 oid of 8: .1.3.6.1.2.1.1.5.0
* 05 00 null
*
*
* Response for sysname:
* 30 30
* 02 01 00
* 04 06 70 75 62 6C 69 63 "public"
* A2 23
* 02 04 27 05 36 A9 seqID
* 02 01 00
* 02 01 00
* 30 15
* 30 13
* 06 08 2B 06 01 02 01 01 05 00
* 04 07 6C 61 70 74 6F 70 6F "laptopo"
*
*/
/*
* The following array defines the frame format, sizes are ignored on read
* but must be filled on write, so mark them specially
*/
#define BYTE_SIZE 0xff
#define BYTE_IGNORE 0xfe
#define BYTE_PDU 0xfd
static uint8_t match_array[] = {
0x30, BYTE_SIZE,
0x02, 0x01, 0x00,
0x04, 0x06, 0x70, 0x75, 0x62, 0x6C, 0x69, 0x63,
BYTE_PDU, BYTE_SIZE,
0x02, 0x04, BYTE_IGNORE, BYTE_IGNORE, BYTE_IGNORE, BYTE_IGNORE,
0x02, 0x01, 0x00,
0x02, 0x01, 0x00,
0x30, BYTE_SIZE,
0x30, BYTE_SIZE,
0x06, BYTE_IGNORE, /* oid follows */
};
/* And, now, work out your generic frame responder... */
static int snmp_respond(uint8_t *buf)
{
struct snmp_oid *oid;
uint8_t *newbuf;
int i, len;
for (i = 0; i < sizeof(match_array); i++) {
switch (match_array[i]) {
case BYTE_SIZE:
case BYTE_IGNORE:
continue;
case BYTE_PDU:
if (buf[i] != 0xA0)
return -1;
break;
default:
if (buf[i] != match_array[i])
return -1;
}
}
net_verbose("%s: match ok\n", __func__);
newbuf = buf + i;
for (oid = oid_array; oid->oid_len; oid++)
if (!memcmp(oid->oid_match, newbuf, oid->oid_len))
break;
if (!oid->oid_len)
return -1;
net_verbose("%s: oid found: calling %p\n", __func__, oid->fill);
/* Phew.... we matched the OID, so let's call the filler */
newbuf += oid->oid_len;
len = oid->fill(newbuf);
/* now fix all size fields and change PDU */
for (i = 0; i < sizeof(match_array); i++) {
int remain = (sizeof(match_array) - 1) - i;
if (match_array[i] == BYTE_PDU)
buf[i] = 0xA2; /* get response */
if (match_array[i] != BYTE_SIZE)
continue;
net_verbose("offset %i 0x%02x is len %i\n", i, i,
remain + oid->oid_len + len);
buf[i] = remain + oid->oid_len + len;
}
net_verbose("%s: returning %i bytes\n", __func__, len + (newbuf - buf));
return len + (newbuf - buf);
}
/* receive snmp through the UDP mechanism */
static int snmp_poll(void)
{
struct wr_sockaddr addr;
uint8_t buf[200];
int len;
/* no need to wait for IP address: we won't get queries */
len = ptpd_netif_recvfrom(snmp_socket, &addr,
buf, sizeof(buf), NULL);
if (len <= UDP_END + sizeof(match_array))
return 0;
len = snmp_respond(buf + UDP_END);
if (len < 0)
return 0;
len += UDP_END;
fill_udp(buf, len, NULL);
ptpd_netif_sendto(snmp_socket, &addr, buf, len, 0);
return 1;
}
DEFINE_WRC_TASK(snmp) = {
.name = "snmp",
.enable = &link_status,
.init = snmp_init,
.job = snmp_poll,
};
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