ipaddress_ioctl.c

开发snmp的开发包有两个开放的SNMP开发库

/*
 *  Interface MIB architecture support
 *
 * $Id: ipaddress_ioctl.c 16381 2007-05-17 21:53:28Z hardaker $
 */
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include "mibII/mibII_common.h"

#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <net-snmp/data_access/ipaddress.h>
#include <net-snmp/data_access/interface.h>

#include "ip-mib/ipAddressTable/ipAddressTable_constants.h"
#include "if-mib/data_access/interface_ioctl.h"

#include <errno.h>
#include <net/if.h>
#include <sys/ioctl.h>

#include "ipaddress_ioctl.h"

static void _print_flags(short flags);

#define LIST_TOKEN "ioctl_extras"

/*
 * get extra structure
 *
 * @returns the extras structure from the entry
 */
_ioctl_extras *
netsnmp_ioctl_ipaddress_extras_get(netsnmp_ipaddress_entry *entry)
{
    if ((NULL == entry) || (NULL == entry->arch_data))
        return NULL;

    return netsnmp_get_list_data(entry->arch_data, LIST_TOKEN);
}

/**
 * initialize ioctl extras
 *
 * @returns _ioctl_extras pointer, or NULL on error
 */
_ioctl_extras *
netsnmp_ioctl_ipaddress_entry_init(netsnmp_ipaddress_entry *entry)
{
    netsnmp_data_list *node;
    _ioctl_extras     *extras;

    if (NULL == entry)
        return NULL;

    extras = SNMP_MALLOC_TYPEDEF(_ioctl_extras);
    if (NULL == extras)
        return NULL;

    node = netsnmp_create_data_list(LIST_TOKEN, extras, free);
    if (NULL == node) {
        free(extras);
        return NULL;
    }

    netsnmp_data_list_add_node( &entry->arch_data, node );
    
    return extras;
}

/**
 * cleanup ioctl extras
 */
void
netsnmp_ioctl_ipaddress_entry_cleanup(netsnmp_ipaddress_entry *entry)
{
    if (NULL == entry) {
        netsnmp_assert(NULL != entry);
        return;
    }

    if (NULL == entry->arch_data) {
        netsnmp_assert(NULL != entry->arch_data);
        return;
    }

    netsnmp_remove_list_node(&entry->arch_data, LIST_TOKEN);
}

/**
 * copy ioctl extras
 *
 * @retval  0: success
 * @retval <0: error
 */
int
netsnmp_ioctl_ipaddress_entry_copy(netsnmp_ipaddress_entry *lhs,
                                   netsnmp_ipaddress_entry *rhs)
{
    _ioctl_extras *lhs_extras, *rhs_extras;
    int            rc = SNMP_ERR_NOERROR;

    if ((NULL == lhs) || (NULL == rhs)) {
        netsnmp_assert((NULL != lhs) && (NULL != rhs));
        return -1;
    }

    rhs_extras = netsnmp_ioctl_ipaddress_extras_get(rhs);
    lhs_extras = netsnmp_ioctl_ipaddress_extras_get(lhs);
    if (NULL == rhs_extras) {
        if (NULL != lhs_extras)
            netsnmp_ioctl_ipaddress_entry_cleanup(lhs);
    }
    else {
        if (NULL == lhs_extras)
            lhs_extras = netsnmp_ioctl_ipaddress_entry_init(lhs);
        
        if (NULL != lhs_extras)
            memcpy(lhs_extras, rhs_extras, sizeof(_ioctl_extras));
        else
            rc = -1;
    }

    return rc;
}

/**
 * load ipv4 address via ioctl
 */
int
_netsnmp_ioctl_ipaddress_container_load_v4(netsnmp_container *container,
                                                  int idx_offset)
{
    int             i, sd, rc = 0, interfaces = 0;
    struct ifconf   ifc;
    struct ifreq   *ifrp;
    struct sockaddr save_addr;
    struct sockaddr_in * si;
    netsnmp_ipaddress_entry *entry;
    _ioctl_extras           *extras;

    if ((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        snmp_log(LOG_ERR, "could not create socket\n");
        return -1;
    }

    interfaces =
        netsnmp_access_ipaddress_ioctl_get_interface_count(sd, &ifc);
    if(interfaces < 0) {
        close(sd);
        return -2;
    }
    netsnmp_assert(NULL != ifc.ifc_buf);
    DEBUGMSGTL(("access:ipaddress:container", "processing %d interfaces\n", interfaces));

    ifrp = ifc.ifc_req;
    for(i=0; i < interfaces; ++i, ++ifrp) {

        DEBUGMSGTL(("access:ipaddress:container",
                    " interface %d, %s\n", i, ifrp->ifr_name));
        /*
         */
        entry = netsnmp_access_ipaddress_entry_create();
        if(NULL == entry) {
            rc = -3;
            break;
        }
        entry->ns_ia_index = ++idx_offset;

        /*
         * save if name
         */
        extras = netsnmp_ioctl_ipaddress_extras_get(entry);
        memcpy(extras->name, ifrp->ifr_name, sizeof(extras->name));

        /*
         * each time we make an ioctl, we need to specify the address, but
         * it will be overwritten in the call. so we save address here.
         */
        save_addr = ifrp->ifr_addr;

        /*
         * set indexes
         */
        netsnmp_assert(AF_INET == ifrp->ifr_addr.sa_family);
        si = (struct sockaddr_in *) &ifrp->ifr_addr;
        entry->ia_address_len = sizeof(si->sin_addr.s_addr);
        memcpy(entry->ia_address, &si->sin_addr.s_addr,
               entry->ia_address_len);

        /*
         * get ifindex
         */
        {
            /*
             * I think that Linux and Solaris both use ':' in the
             * interface name for aliases. When a new arch is added
             * that uses some other indicator, a new function, maybe
             * netsnmp_access_ipaddress_entry_name_alias_check(), will
             * need to be written.
             */
            char *ptr = strchr(ifrp->ifr_name, ':');
            if (NULL != ptr) {
                entry->flags |= NETSNMP_ACCESS_IPADDRESS_ISALIAS;
                *ptr = 0;
            }
        }
        entry->if_index =
            netsnmp_access_interface_ioctl_ifindex_get(sd, ifrp->ifr_name);
        if (0 == entry->if_index) {
            snmp_log(LOG_ERR,"no ifindex found for interface\n");
            netsnmp_access_ipaddress_entry_free(entry);
            continue;
        }

        /*
         * get netmask
         */
        ifrp->ifr_addr = save_addr;
        if (ioctl(sd, SIOCGIFNETMASK, ifrp) < 0) {
            snmp_log(LOG_ERR,
                     "error getting netmask for interface %d\n", i);
            netsnmp_access_ipaddress_entry_free(entry);
            continue;
        }
        netsnmp_assert(AF_INET == ifrp->ifr_addr.sa_family);
        si = (struct sockaddr_in *) &ifrp->ifr_addr;
        entry->ia_prefix_len =
            netsnmp_ipaddress_ipv4_prefix_len(si->sin_addr.s_addr);

        /*
         * get flags
         */
        ifrp->ifr_addr = save_addr;
        if (ioctl(sd, SIOCGIFFLAGS, ifrp) < 0) {
            snmp_log(LOG_ERR,
                     "error getting if_flags for interface %d\n", i);
            netsnmp_access_ipaddress_entry_free(entry);
            continue;
        }
        extras->flags = ifrp->ifr_flags;

        entry->ia_type = IPADDRESSTYPE_UNICAST; /* assume unicast? */

        /** entry->ia_prefix_oid ? */

        /*
         * per the MIB:
         *   In the absence of other information, an IPv4 address is
         *   always preferred(1).
         */
        entry->ia_status = IPADDRESSSTATUSTC_PREFERRED;

        /*
         * can we figure out if an address is from DHCP?
         * use manual until then...
         */
        entry->ia_origin = IPADDRESSORIGINTC_MANUAL;

        DEBUGIF("access:ipaddress:container") {
            DEBUGMSGT_NC(("access:ipaddress:container",
                          " if %d: addr len %d, index 0x%x\n",
                          i, entry->ia_address_len, entry->if_index));
            if (4 == entry->ia_address_len)
                DEBUGMSGT_NC(("access:ipaddress:container", " address %p\n",
                              *((void**)entry->ia_address)));
            DEBUGMSGT_NC(("access:ipaddress:container", "flags 0x%x\n",
                          extras->flags));
            _print_flags(extras->flags);

        }

        /*
         * add entry to container
         */
        if (CONTAINER_INSERT(container, entry) < 0)
        {
            DEBUGMSGTL(("access:ipaddress:container","error with ipaddress_entry: insert into container failed.\n"));
            netsnmp_access_ipaddress_entry_free(entry);
            continue;
        }
    }

    /*
     * clean up
     */
    free(ifc.ifc_buf);
    close(sd);

    /*
     * return number of interfaces seen
     */
    if(rc < 0)
        return rc;

    return idx_offset;