appldata_net_sum.c

Go to the documentation of this file.

/*
 * Data gathering module for Linux-VM Monitor Stream, Stage 1.
 * Collects accumulated network statistics (Packets received/transmitted,
 * dropped, errors, ...).
 *
 * Copyright IBM Corp. 2003, 2006
 *
 * Author: Gerald Schaefer <[email protected]>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/netdevice.h>
#include <net/net_namespace.h>

#include "appldata.h"


/*
 * Network data
 *
 * This is accessed as binary data by z/VM. If changes to it can't be avoided,
 * the structure version (product ID, see appldata_base.c) needs to be changed
 * as well and all documentation and z/VM applications using it must be updated.
 *
 * The record layout is documented in the Linux for zSeries Device Drivers
 * book:
 * http://oss.software.ibm.com/developerworks/opensource/linux390/index.shtml
 */
static struct appldata_net_sum_data {
    u64 timestamp;
    u32 sync_count_1;   /* after VM collected the record data, */
    u32 sync_count_2;   /* sync_count_1 and sync_count_2 should be the
                   same. If not, the record has been updated on
                   the Linux side while VM was collecting the
                   (possibly corrupt) data */

    u32 nr_interfaces;  /* nr. of network interfaces being monitored */

    u32 padding;        /* next value is 64-bit aligned, so these */
                /* 4 byte would be padded out by compiler */

    u64 rx_packets;     /* total packets received        */
    u64 tx_packets;     /* total packets transmitted     */
    u64 rx_bytes;       /* total bytes received          */
    u64 tx_bytes;       /* total bytes transmitted       */
    u64 rx_errors;      /* bad packets received          */
    u64 tx_errors;      /* packet transmit problems      */
    u64 rx_dropped;     /* no space in linux buffers     */
    u64 tx_dropped;     /* no space available in linux   */
    u64 collisions;     /* collisions while transmitting */
} __attribute__((packed)) appldata_net_sum_data;


/*
 * appldata_get_net_sum_data()
 *
 * gather accumulated network statistics
 */
static void appldata_get_net_sum_data(void *data)
{
    int i;
    struct appldata_net_sum_data *net_data;
    struct net_device *dev;
    unsigned long rx_packets, tx_packets, rx_bytes, tx_bytes, rx_errors,
            tx_errors, rx_dropped, tx_dropped, collisions;

    net_data = data;
    net_data->sync_count_1++;

    i = 0;
    rx_packets = 0;
    tx_packets = 0;
    rx_bytes   = 0;
    tx_bytes   = 0;
    rx_errors  = 0;
    tx_errors  = 0;
    rx_dropped = 0;
    tx_dropped = 0;
    collisions = 0;

    rcu_read_lock();
    for_each_netdev_rcu(&init_net, dev) {
        const struct rtnl_link_stats64 *stats;
        struct rtnl_link_stats64 temp;

        stats = dev_get_stats(dev, &temp);
        rx_packets += stats->rx_packets;
        tx_packets += stats->tx_packets;
        rx_bytes   += stats->rx_bytes;
        tx_bytes   += stats->tx_bytes;
        rx_errors  += stats->rx_errors;
        tx_errors  += stats->tx_errors;
        rx_dropped += stats->rx_dropped;
        tx_dropped += stats->tx_dropped;
        collisions += stats->collisions;
        i++;
    }
    rcu_read_unlock();

    net_data->nr_interfaces = i;
    net_data->rx_packets = rx_packets;
    net_data->tx_packets = tx_packets;
    net_data->rx_bytes   = rx_bytes;
    net_data->tx_bytes   = tx_bytes;
    net_data->rx_errors  = rx_errors;
    net_data->tx_errors  = tx_errors;
    net_data->rx_dropped = rx_dropped;
    net_data->tx_dropped = tx_dropped;
    net_data->collisions = collisions;

    net_data->timestamp = get_clock();
    net_data->sync_count_2++;
}


static struct appldata_ops ops = {
    .name      = "net_sum",
    .record_nr = APPLDATA_RECORD_NET_SUM_ID,
    .size      = sizeof(struct appldata_net_sum_data),
    .callback  = &appldata_get_net_sum_data,
    .data      = &appldata_net_sum_data,
    .owner     = THIS_MODULE,
    .mod_lvl   = {0xF0, 0xF0},      /* EBCDIC "00" */
};


/*
 * appldata_net_init()
 *
 * init data, register ops
 */
static int __init appldata_net_init(void)
{
    return appldata_register_ops(&ops);
}

/*
 * appldata_net_exit()
 *
 * unregister ops
 */
static void __exit appldata_net_exit(void)
{
    appldata_unregister_ops(&ops);
}


module_init(appldata_net_init);
module_exit(appldata_net_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Gerald Schaefer");
MODULE_DESCRIPTION("Linux-VM Monitor Stream, accumulated network statistics");