addons/network-devices/snmp.c

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Licensed under the Academic Free License version 2.1
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <glib.h>

#include <libhal.h>
#include <logger.h>

#undef PACKAGE_STRING
#undef PACKAGE_VERSION

#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>

#include "network-discovery.h"
#include "printer.h"

#define NP(x)   (x?x:"NULL")

static GList *new_addrs = NULL;

static void
add_snmp_device(LibHalContext *ctx, char *parent, char *name, char *community)
{
    /* most printers listen on the appsocket port (9100) */
    if (is_listening(name, 9100) == 0) {
        char device[128];

        snprintf(device, sizeof (device), "socket://%s:9100", name);

        add_network_printer(ctx, parent, name, device, community);
    }

    /*
     * This would be a good place to detect other types of devices or other
     * device capabilities.  scanners, removable media, storage, ...
     */
}

static int
snmp_response_cb(int operation, struct snmp_session *sp, int reqid,
        struct snmp_pdu *pdu, void *data)
{
    struct sockaddr_in *addr = pdu->transport_data;
    char *name;

    name = inet_ntoa(addr->sin_addr);

    /* have we already seen this network device */
    if (device_seen(name) == FALSE)
        new_addrs = g_list_append(new_addrs, strdup(name));

    return (0);
}

gboolean
scan_for_devices_using_snmp(LibHalContext *ctx, char *parent, char *community,
        char *network)
{
    struct snmp_session session, *ss;
    struct snmp_pdu *request = NULL, *response = NULL;
    oid Oid[MAX_OID_LEN];
    unsigned int oid_len = MAX_OID_LEN;
    GList *elem;

    HAL_DEBUG(("scan_for_devices_using_snmp(0x%8.8x, %s, %s, %s)",
        ctx, NP(parent), NP(community), NP(network)));

    init_snmp("snmp-scan");
    init_mib();

    /* initialize the SNMP session */
    snmp_sess_init(&session);
    session.peername = network;
    session.community = (uchar_t *)community;
    session.community_len = strlen((const char *)session.community);
    session.version = SNMP_VERSION_1;

    if ((ss = snmp_open(&session)) == NULL)
        return (FALSE);

    /* initialize the request PDU */
    request = snmp_pdu_create(SNMP_MSG_GET);

    /* add the requested data (everyone should have a sysDescr.0) */
    if (!read_objid("SNMPv2-MIB::sysDescr.0", Oid, &oid_len))
        snmp_perror("sysDescr.0");
    snmp_add_null_var(request, Oid, oid_len);

    snmp_async_send(ss, request, snmp_response_cb, NULL);

    /* detect any new devices */
    while (1) {
        int fds = 0, block = 0;
        fd_set fdset;
        struct timeval timeout;

        FD_ZERO(&fdset);
        snmp_select_info(&fds, &fdset, &timeout, &block);
        fds = select(fds, &fdset, NULL, NULL, block ? NULL : &timeout);
        if (fds < 0) {
            perror("select failed");
            break;
        } if (fds == 0) {
            break;
        } else {
            snmp_read(&fdset);
        }
    }

    snmp_close(ss);

    /* add the newly detected devices */
    for (elem = new_addrs; elem != NULL; elem = g_list_next(elem)) {
        add_snmp_device(ctx, parent, (char *)elem->data, community);
        free(elem->data);
    }
    g_list_free(new_addrs);
    new_addrs = NULL;

    return (TRUE);
}