sysctl_net_core.c

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/* -*- linux-c -*-
 * sysctl_net_core.c: sysctl interface to net core subsystem.
 *
 * Begun April 1, 1996, Mike Shaver.
 * Added /proc/sys/net/core directory entry (empty =) ). [MS]
 */

#include <linux/mm.h>
#include <linux/sysctl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/netdevice.h>
#include <linux/ratelimit.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kmemleak.h>

#include <net/ip.h>
#include <net/sock.h>
#include <net/net_ratelimit.h>

#ifdef CONFIG_RPS
static int rps_sock_flow_sysctl(ctl_table *table, int write,
                void __user *buffer, size_t *lenp, loff_t *ppos)
{
    unsigned int orig_size, size;
    int ret, i;
    ctl_table tmp = {
        .data = &size,
        .maxlen = sizeof(size),
        .mode = table->mode
    };
    struct rps_sock_flow_table *orig_sock_table, *sock_table;
    static DEFINE_MUTEX(sock_flow_mutex);

    mutex_lock(&sock_flow_mutex);

    orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
                    lockdep_is_held(&sock_flow_mutex));
    size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;

    ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);

    if (write) {
        if (size) {
            if (size > 1<<30) {
                /* Enforce limit to prevent overflow */
                mutex_unlock(&sock_flow_mutex);
                return -EINVAL;
            }
            size = roundup_pow_of_two(size);
            if (size != orig_size) {
                sock_table =
                    vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
                if (!sock_table) {
                    mutex_unlock(&sock_flow_mutex);
                    return -ENOMEM;
                }

                sock_table->mask = size - 1;
            } else
                sock_table = orig_sock_table;

            for (i = 0; i < size; i++)
                sock_table->ents[i] = RPS_NO_CPU;
        } else
            sock_table = NULL;

        if (sock_table != orig_sock_table) {
            rcu_assign_pointer(rps_sock_flow_table, sock_table);
            if (sock_table)
                static_key_slow_inc(&rps_needed);
            if (orig_sock_table) {
                static_key_slow_dec(&rps_needed);
                synchronize_rcu();
                vfree(orig_sock_table);
            }
        }
    }

    mutex_unlock(&sock_flow_mutex);

    return ret;
}
#endif /* CONFIG_RPS */

static struct ctl_table net_core_table[] = {
#ifdef CONFIG_NET
    {
        .procname   = "wmem_max",
        .data       = &sysctl_wmem_max,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "rmem_max",
        .data       = &sysctl_rmem_max,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "wmem_default",
        .data       = &sysctl_wmem_default,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "rmem_default",
        .data       = &sysctl_rmem_default,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "dev_weight",
        .data       = &weight_p,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "netdev_max_backlog",
        .data       = &netdev_max_backlog,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
#ifdef CONFIG_BPF_JIT
    {
        .procname   = "bpf_jit_enable",
        .data       = &bpf_jit_enable,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
#endif
    {
        .procname   = "netdev_tstamp_prequeue",
        .data       = &netdev_tstamp_prequeue,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "message_cost",
        .data       = &net_ratelimit_state.interval,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec_jiffies,
    },
    {
        .procname   = "message_burst",
        .data       = &net_ratelimit_state.burst,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec,
    },
    {
        .procname   = "optmem_max",
        .data       = &sysctl_optmem_max,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
#ifdef CONFIG_RPS
    {
        .procname   = "rps_sock_flow_entries",
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = rps_sock_flow_sysctl
    },
#endif
#endif /* CONFIG_NET */
    {
        .procname   = "netdev_budget",
        .data       = &netdev_budget,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    {
        .procname   = "warnings",
        .data       = &net_msg_warn,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    { }
};

static struct ctl_table netns_core_table[] = {
    {
        .procname   = "somaxconn",
        .data       = &init_net.core.sysctl_somaxconn,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec
    },
    { }
};

static __net_init int sysctl_core_net_init(struct net *net)
{
    struct ctl_table *tbl;

    net->core.sysctl_somaxconn = SOMAXCONN;

    tbl = netns_core_table;
    if (!net_eq(net, &init_net)) {
        tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
        if (tbl == NULL)
            goto err_dup;

        tbl[0].data = &net->core.sysctl_somaxconn;
    }

    net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
    if (net->core.sysctl_hdr == NULL)
        goto err_reg;

    return 0;

err_reg:
    if (tbl != netns_core_table)
        kfree(tbl);
err_dup:
    return -ENOMEM;
}

static __net_exit void sysctl_core_net_exit(struct net *net)
{
    struct ctl_table *tbl;

    tbl = net->core.sysctl_hdr->ctl_table_arg;
    unregister_net_sysctl_table(net->core.sysctl_hdr);
    BUG_ON(tbl == netns_core_table);
    kfree(tbl);
}

static __net_initdata struct pernet_operations sysctl_core_ops = {
    .init = sysctl_core_net_init,
    .exit = sysctl_core_net_exit,
};

static __init int sysctl_core_init(void)
{
    register_net_sysctl(&init_net, "net/core", net_core_table);
    return register_pernet_subsys(&sysctl_core_ops);
}

fs_initcall(sysctl_core_init);