interface_linux.c

开发snmp的开发包有两个开放的SNMP开发库

/*
 *  Interface MIB architecture support
 *
 * $Id: interface_linux.c 16595 2007-07-06 21:14:03Z rstory $
 */
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>

#ifdef HAVE_LINUX_ETHTOOL_H
#include <linux/types.h>
typedef __u64 u64;         /* hack, so we may include kernel's ethtool.h */
typedef __u32 u32;         /* ditto */
typedef __u16 u16;         /* ditto */
typedef __u8 u8;           /* ditto */
#include <linux/ethtool.h>
#endif /* HAVE_LINUX_ETHTOOL_H */

#include "mibII/mibII_common.h"
#include "if-mib/ifTable/ifTable_constants.h"

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

#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#else
#error "linux should have sys/ioctl header"
#endif

#include <net-snmp/data_access/interface.h>
#include <net-snmp/data_access/ipaddress.h>
#include "if-mib/data_access/interface.h"
#include "interface_ioctl.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include <linux/sockios.h>

#ifndef IF_NAMESIZE
#define IF_NAMESIZE 16
#endif

unsigned int
netsnmp_linux_interface_get_if_speed(int fd, const char *name);
#ifdef HAVE_LINUX_ETHTOOL_H
unsigned int
netsnmp_linux_interface_get_if_speed_mii(int fd, const char *name);
#endif

#define PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME_MS "/proc/sys/net/ipv%d/neigh/%s/retrans_time_ms"
#define PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME    "/proc/sys/net/ipv%d/neigh/%s/retrans_time"
static const char *proc_sys_retrans_time;
static unsigned short retrans_time_factor = 1;


#define PROC_SYS_NET_IPVx_BASE_REACHABLE_TIME_MS "/proc/sys/net/ipv%d/neigh/%s/base_reachable_time_ms"
#define PROC_SYS_NET_IPVx_BASE_REACHABLE_TIME "/proc/sys/net/ipv%d/neigh/%s/base_reachable_time"
static const char *proc_sys_basereachable_time;
static unsigned short basereachable_time_ms = 0;
void
netsnmp_arch_interface_init(void)
{
    /*
     * Check which retransmit time interface is available
     */
    char proc_path[ 64+IF_NAMESIZE];
    char proc_path2[64+IF_NAMESIZE];
    struct stat st;

    snprintf(proc_path,  sizeof(proc_path),
             PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME_MS, 6, "default");
    snprintf(proc_path2, sizeof(proc_path2),
             PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME_MS, 4, "default");

    if ((stat(proc_path, &st) == 0) || (stat(proc_path2, &st) == 0)) {
        proc_sys_retrans_time = PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME_MS;
    } else {
        proc_sys_retrans_time = PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME;
        retrans_time_factor = 10;
    }

    snprintf(proc_path,  sizeof(proc_path),  PROC_SYS_NET_IPVx_BASE_REACHABLE_TIME_MS, 6, "default");
    snprintf(proc_path2,  sizeof(proc_path),  PROC_SYS_NET_IPVx_BASE_REACHABLE_TIME, 4, "default");

    if ((stat(proc_path, &st) == 0) || (stat(proc_path2, &st) == 0)) {
        proc_sys_basereachable_time = PROC_SYS_NET_IPVx_BASE_REACHABLE_TIME_MS;
        basereachable_time_ms = 1;
    }
    else {
        proc_sys_basereachable_time = PROC_SYS_NET_IPVx_BASE_REACHABLE_TIME;
    }
}

/*
 * find the ifIndex for an interface name
 * NOTE: The Linux version is not efficient for large numbers of calls.
 *   consider using netsnmp_access_interface_ioctl_ifindex_get()
 *   for loops which need to look up a lot of indexes.
 *
 * @retval 0 : no index found
 * @retval >0: ifIndex for interface
 */
oid
netsnmp_arch_interface_index_find(const char *name)
{
    return netsnmp_access_interface_ioctl_ifindex_get(-1, name);
}


/*
 * check for ipv6 addresses
 */
void
_arch_interface_has_ipv6(oid if_index, u_int *flags,
                         netsnmp_container *addr_container)
{
#ifdef NETSNMP_ENABLE_IPV6
    netsnmp_ipaddress_entry *addr_entry = NULL;
    netsnmp_iterator        *addr_it = NULL;
    u_int                    addr_container_flags = 0; /* must init to 0 */
#endif

    if (NULL == flags)
        return;

    *flags &= ~NETSNMP_INTERFACE_FLAGS_HAS_IPV6;

#ifdef NETSNMP_ENABLE_IPV6
    /*
     * get ipv6 addresses
     */
    if (NULL == addr_container) {
        /*
         * we only care about ipv6, if we need to allocate our own
         * temporary container. set the flags (which we also use later
         * to determine if we need to free the container).
         */
        addr_container_flags = NETSNMP_ACCESS_IPADDRESS_LOAD_IPV6_ONLY;
        addr_container =
            netsnmp_access_ipaddress_container_load(NULL,
                                                    addr_container_flags);
        if (NULL == addr_container) {
            DEBUGMSGTL(("access:ifcontainer",
                        "couldn't get ip addresses container\n"));
            return;
        }
    }
    else {
        /*
         * addr_container flags must be 0, so we don't release the
         * user's container.
         */
        netsnmp_assert(0 == addr_container_flags);
    }


    /*
     * get an ipaddress container iterator, and look for ipv6 addrs
     */   
    addr_it = CONTAINER_ITERATOR(addr_container);
    if (NULL == addr_it) {
        DEBUGMSGTL(("access:ifcontainer",
                    "couldn't get ip addresses iterator\n"));
        if (0!=addr_container_flags)
            netsnmp_access_ipaddress_container_free(addr_container, 0);
        return;
    }

    addr_entry = ITERATOR_FIRST(addr_it);
    for( ; addr_entry ; addr_entry = ITERATOR_NEXT(addr_it) ) {
        /*
         * skip non matching indexes and ipv4 addresses
         */
        if ((if_index != addr_entry->if_index) ||
            (4 == addr_entry->ia_address_len))
            continue;

        /*
         * found one! no need to keep looking, set the flag and bail
         */
        *flags |= NETSNMP_INTERFACE_FLAGS_HAS_IPV6;
        break;
    }

    /*
     * make mama proud and clean up after ourselves
     */
    ITERATOR_RELEASE(addr_it);
    if (0!=addr_container_flags)
        netsnmp_access_ipaddress_container_free(addr_container, 0);    
#endif
}

/**
 * @internal
 */
static void
_arch_interface_flags_v4_get(netsnmp_interface_entry *entry)
{
    FILE           *fin;
    char            line[256];

    /*
     * get the retransmit time
     */
    snprintf(line,sizeof(line), proc_sys_retrans_time, 4,
             entry->name);
    if (!(fin = fopen(line, "r"))) {
        DEBUGMSGTL(("access:interface",
                    "Failed to open %s\n", line));
    }
    else {
        if (fgets(line, sizeof(line), fin)) {
            entry->retransmit_v4 = atoi(line) * retrans_time_factor;
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_V4_RETRANSMIT;
        }
        fclose(fin);
    }
}


#ifdef NETSNMP_ENABLE_IPV6
/**
 * @internal
 */
static void
_arch_interface_flags_v6_get(netsnmp_interface_entry *entry)
{
    FILE           *fin;
    char            line[256];

    /*
     * get the retransmit time
     */
    snprintf(line,sizeof(line), proc_sys_retrans_time, 6,
             entry->name);
    if (!(fin = fopen(line, "r"))) {
        DEBUGMSGTL(("access:interface",
                    "Failed to open %s\n", line));
    }
    else {
        if (fgets(line, sizeof(line), fin)) {
            entry->retransmit_v6 = atoi(line) * retrans_time_factor;
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_V6_RETRANSMIT;
        }
        fclose(fin);
    }

    /*
     * get the forwarding status
     */
    snprintf(line, sizeof(line), "/proc/sys/net/ipv6/conf/%s/forwarding",
             entry->name);
    if (!(fin = fopen(line, "r"))) {
        DEBUGMSGTL(("access:interface",
                    "Failed to open %s\n", line));
    }
    else {
        if (fgets(line, sizeof(line), fin)) {
            entry->forwarding_v6 = atoi(line);
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_V6_FORWARDING;
        }
        fclose(fin);
    }

    /*
     * get the reachable time
     */
    snprintf(line, sizeof(line), proc_sys_basereachable_time, 6, entry->name);
    if (!(fin = fopen(line, "r"))) {
        DEBUGMSGTL(("access:interface",
                    "Failed to open %s\n", line));
    }
    else {
        if (fgets(line, sizeof(line), fin)) {
            if (basereachable_time_ms) {
                entry->reachable_time = atoi(line); /* millisec */
            } else {
                entry->reachable_time = atoi(line)*1000; /* sec to  millisec */
            }

            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_V6_REACHABLE;
        }
        fclose(fin);
    }
}
#endif /* NETSNMP_ENABLE_IPV6 */

/**
 * @internal
 */
static int
_parse_stats(netsnmp_interface_entry *entry, char *stats, int expected)
{
    /*
     * scanline_2_2:
     *  [               IN                        ]
     *   byte pkts errs drop fifo frame cmprs mcst |
     *  [               OUT                               ]
     *   byte pkts errs drop fifo colls carrier compressed
     */
#ifdef SCNuMAX
    uintmax_t       rec_pkt, rec_oct, rec_err, rec_drop, rec_mcast;
    uintmax_t       snd_pkt, snd_oct, snd_err, snd_drop, coll;
    const char     *scan_line_2_2 =
        "%"   SCNuMAX " %"  SCNuMAX " %"  SCNuMAX " %"  SCNuMAX
        " %*" SCNuMAX " %*" SCNuMAX " %*" SCNuMAX " %"  SCNuMAX
        " %"  SCNuMAX " %"  SCNuMAX " %"  SCNuMAX " %"  SCNuMAX
        " %*" SCNuMAX " %"  SCNuMAX;
    const char     *scan_line_2_0 =
        "%"   SCNuMAX " %"  SCNuMAX " %*" SCNuMAX " %*" SCNuMAX
        " %*" SCNuMAX " %"  SCNuMAX " %"  SCNuMAX " %*" SCNuMAX
        " %*" SCNuMAX " %"  SCNuMAX;
#else
    unsigned long   rec_pkt, rec_oct, rec_err, rec_drop, rec_mcast;
    unsigned long   snd_pkt, snd_oct, snd_err, snd_drop, coll;
    const char     *scan_line_2_2 =
        "%lu %lu %lu %lu %*lu %*lu %*lu %lu %lu %lu %lu %lu %*lu %lu";
    const char     *scan_line_2_0 =
        "%lu %lu %*lu %*lu %*lu %lu %lu %*lu %*lu %lu";
#endif
    static const char     *scan_line_to_use = NULL;
    int             scan_count;

    if (10 == expected)
        scan_line_to_use = scan_line_2_2;
    else {
        netsnmp_assert(5 == expected);
        scan_line_to_use = scan_line_2_0;
    }

    while (*stats == ' ')
        stats++;

    if ((*stats == 'N') &&
        (0 == strncmp(stats, "No statistics available",
                      sizeof("No statistics available"))))
        return -1;

    /*
     * Now parse the rest of the line (i.e. starting from 'stats')
     *      to extract the relevant statistics, and populate
     *      data structure accordingly.
     * Use the entry flags field to indicate which counters are valid
     */
    rec_pkt = rec_oct = rec_err = rec_drop = rec_mcast = 0;
    snd_pkt = snd_oct = snd_err = snd_drop = coll = 0;
    if (scan_line_to_use == scan_line_2_2) {
        scan_count = sscanf(stats, scan_line_to_use,
                            &rec_oct, &rec_pkt, &rec_err, &rec_drop, &rec_mcast,
                            &snd_oct, &snd_pkt, &snd_err, &snd_drop,
                            &coll);
        if (scan_count == expected) {
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_BYTES;
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_DROPS;
            /*
             *  2.4 kernel includes a single multicast (input) counter?
             */
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_MCAST_PKTS;
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_HIGH_SPEED;
#ifdef SCNuMAX   /* XXX - should be flag for 64-bit variables */
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_HIGH_BYTES;
            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_HIGH_PACKETS;
#endif
        }
    } else {
        scan_count = sscanf(stats, scan_line_to_use,
                            &rec_pkt, &rec_err,
                            &snd_pkt, &snd_err, &coll);
        if (scan_count == expected) {
            entry->ns_flags &= ~NETSNMP_INTERFACE_FLAGS_HAS_MCAST_PKTS;
            rec_oct = rec_drop = 0;
            snd_oct = snd_drop = 0;
        }
    }
    if(scan_count != expected) {
        snmp_log(LOG_ERR,
                 "error scanning interface data (expected %d, got %d)\n",
                 expected, scan_count);
        return scan_count;
    }
    entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_ACTIVE;
    
    /*
     * linux previous to 1.3.~13 may miss transmitted loopback pkts: 
     */
    if (!strcmp(entry->name, "lo") && rec_pkt > 0 && !snd_pkt)
        snd_pkt = rec_pkt;
    
    /*
     * subtract out multicast packets from rec_pkt before
     * we store it as unicast counter.
     */
    rec_pkt -= rec_mcast;

    entry->stats.ibytes.low = rec_oct & 0xffffffff;
    entry->stats.iucast.low = rec_pkt & 0xffffffff;
    entry->stats.imcast.low = rec_mcast & 0xffffffff;
    entry->stats.obytes.low = snd_oct & 0xffffffff;
    entry->stats.oucast.low = snd_pkt & 0xffffffff;
#ifdef SCNuMAX   /* XXX - should be flag for 64-bit variables */
    entry->stats.ibytes.high = rec_oct >> 32;
    entry->stats.iucast.high = rec_pkt >> 32;
    entry->stats.imcast.high = rec_mcast >> 32;
    entry->stats.obytes.high = snd_oct >> 32;
    entry->stats.oucast.high = snd_pkt >> 32;
#endif
    entry->stats.ierrors   = rec_err;
    entry->stats.idiscards = rec_drop;
    entry->stats.oerrors   = snd_err;
    entry->stats.odiscards = snd_drop;
    entry->stats.collisions = coll;
    
    /*
     * calculated stats.
     *
     *  we have imcast, but not ibcast.
     */
    entry->stats.inucast = entry->stats.imcast.low +
        entry->stats.ibcast.low;
    entry->stats.onucast = entry->stats.omcast.low +
        entry->stats.obcast.low;
    
    return 0;