root/net/sctp/sysctl.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2002, 2004
 * Copyright (c) 2002 Intel Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * Sysctl related interfaces for SCTP.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    Mingqin Liu           <liuming@us.ibm.com>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Ardelle Fan           <ardelle.fan@intel.com>
 *    Ryan Layer            <rmlayer@us.ibm.com>
 *    Sridhar Samudrala     <sri@us.ibm.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <net/sctp/structs.h>
#include <net/sctp/sctp.h>
#include <linux/sysctl.h>

static int timer_max = 86400000; /* ms in one day */
static int sack_timer_min = 1;
static int sack_timer_max = 500;
static int addr_scope_max = SCTP_SCOPE_POLICY_MAX;
static int rwnd_scale_max = 16;
static int rto_alpha_min = 0;
static int rto_beta_min = 0;
static int rto_alpha_max = 1000;
static int rto_beta_max = 1000;
static int pf_expose_max = SCTP_PF_EXPOSE_MAX;
static int ps_retrans_max = SCTP_PS_RETRANS_MAX;
static int udp_port_max = 65535;

static unsigned long max_autoclose_min = 0;
static unsigned long max_autoclose_max =
        (MAX_SCHEDULE_TIMEOUT / HZ > UINT_MAX)
        ? UINT_MAX : MAX_SCHEDULE_TIMEOUT / HZ;

static int proc_sctp_do_hmac_alg(const struct ctl_table *ctl, int write,
                                 void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_rto_min(const struct ctl_table *ctl, int write,
                                void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_rto_max(const struct ctl_table *ctl, int write, void *buffer,
                                size_t *lenp, loff_t *ppos);
static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write, void *buffer,
                                 size_t *lenp, loff_t *ppos);
static int proc_sctp_do_alpha_beta(const struct ctl_table *ctl, int write,
                                   void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_auth(const struct ctl_table *ctl, int write,
                             void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_probe_interval(const struct ctl_table *ctl, int write,
                                       void *buffer, size_t *lenp, loff_t *ppos);

static struct ctl_table sctp_table[] = {
        {
                .procname       = "sctp_mem",
                .data           = &sysctl_sctp_mem,
                .maxlen         = sizeof(sysctl_sctp_mem),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax
        },
        {
                .procname       = "sctp_rmem",
                .data           = &sysctl_sctp_rmem,
                .maxlen         = sizeof(sysctl_sctp_rmem),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "sctp_wmem",
                .data           = &sysctl_sctp_wmem,
                .maxlen         = sizeof(sysctl_sctp_wmem),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
};

/* The following index defines are used in sctp_sysctl_net_register().
 * If you add new items to the sctp_net_table, please ensure that
 * the index values of these defines hold the same meaning indicated by
 * their macro names when they appear in sctp_net_table.
 */
#define SCTP_RTO_MIN_IDX       0
#define SCTP_RTO_MAX_IDX       1
#define SCTP_PF_RETRANS_IDX    2
#define SCTP_PS_RETRANS_IDX    3

static struct ctl_table sctp_net_table[] = {
        [SCTP_RTO_MIN_IDX] = {
                .procname       = "rto_min",
                .data           = &init_net.sctp.rto_min,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_rto_min,
                .extra1         = SYSCTL_ONE,
                .extra2         = &init_net.sctp.rto_max
        },
        [SCTP_RTO_MAX_IDX] =  {
                .procname       = "rto_max",
                .data           = &init_net.sctp.rto_max,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_rto_max,
                .extra1         = &init_net.sctp.rto_min,
                .extra2         = &timer_max
        },
        [SCTP_PF_RETRANS_IDX] = {
                .procname       = "pf_retrans",
                .data           = &init_net.sctp.pf_retrans,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = &init_net.sctp.ps_retrans,
        },
        [SCTP_PS_RETRANS_IDX] = {
                .procname       = "ps_retrans",
                .data           = &init_net.sctp.ps_retrans,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &init_net.sctp.pf_retrans,
                .extra2         = &ps_retrans_max,
        },
        {
                .procname       = "rto_initial",
                .data           = &init_net.sctp.rto_initial,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = &timer_max
        },
        {
                .procname       = "rto_alpha_exp_divisor",
                .data           = &init_net.sctp.rto_alpha,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_alpha_beta,
                .extra1         = &rto_alpha_min,
                .extra2         = &rto_alpha_max,
        },
        {
                .procname       = "rto_beta_exp_divisor",
                .data           = &init_net.sctp.rto_beta,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_alpha_beta,
                .extra1         = &rto_beta_min,
                .extra2         = &rto_beta_max,
        },
        {
                .procname       = "max_burst",
                .data           = &init_net.sctp.max_burst,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_INT_MAX,
        },
        {
                .procname       = "cookie_preserve_enable",
                .data           = &init_net.sctp.cookie_preserve_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "cookie_hmac_alg",
                .data           = &init_net.sctp.cookie_auth_enable,
                .maxlen         = 8,
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_hmac_alg,
        },
        {
                .procname       = "valid_cookie_life",
                .data           = &init_net.sctp.valid_cookie_life,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = &timer_max
        },
        {
                .procname       = "sack_timeout",
                .data           = &init_net.sctp.sack_timeout,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &sack_timer_min,
                .extra2         = &sack_timer_max,
        },
        {
                .procname       = "hb_interval",
                .data           = &init_net.sctp.hb_interval,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = &timer_max
        },
        {
                .procname       = "association_max_retrans",
                .data           = &init_net.sctp.max_retrans_association,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = SYSCTL_INT_MAX,
        },
        {
                .procname       = "path_max_retrans",
                .data           = &init_net.sctp.max_retrans_path,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = SYSCTL_INT_MAX,
        },
        {
                .procname       = "max_init_retransmits",
                .data           = &init_net.sctp.max_retrans_init,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = SYSCTL_INT_MAX,
        },
        {
                .procname       = "sndbuf_policy",
                .data           = &init_net.sctp.sndbuf_policy,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "rcvbuf_policy",
                .data           = &init_net.sctp.rcvbuf_policy,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "default_auto_asconf",
                .data           = &init_net.sctp.default_auto_asconf,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "addip_enable",
                .data           = &init_net.sctp.addip_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "addip_noauth_enable",
                .data           = &init_net.sctp.addip_noauth,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "prsctp_enable",
                .data           = &init_net.sctp.prsctp_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "reconf_enable",
                .data           = &init_net.sctp.reconf_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "auth_enable",
                .data           = &init_net.sctp.auth_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_auth,
        },
        {
                .procname       = "intl_enable",
                .data           = &init_net.sctp.intl_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ecn_enable",
                .data           = &init_net.sctp.ecn_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "plpmtud_probe_interval",
                .data           = &init_net.sctp.probe_interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_probe_interval,
        },
        {
                .procname       = "udp_port",
                .data           = &init_net.sctp.udp_port,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_sctp_do_udp_port,
                .extra1         = SYSCTL_ZERO,
                .extra2         = &udp_port_max,
        },
        {
                .procname       = "encap_port",
                .data           = &init_net.sctp.encap_port,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = &udp_port_max,
        },
        {
                .procname       = "addr_scope_policy",
                .data           = &init_net.sctp.scope_policy,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = &addr_scope_max,
        },
        {
                .procname       = "rwnd_update_shift",
                .data           = &init_net.sctp.rwnd_upd_shift,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .extra1         = SYSCTL_ONE,
                .extra2         = &rwnd_scale_max,
        },
        {
                .procname       = "max_autoclose",
                .data           = &init_net.sctp.max_autoclose,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
                .extra1         = &max_autoclose_min,
                .extra2         = &max_autoclose_max,
        },
#ifdef CONFIG_NET_L3_MASTER_DEV
        {
                .procname       = "l3mdev_accept",
                .data           = &init_net.sctp.l3mdev_accept,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_ONE,
        },
#endif
        {
                .procname       = "pf_enable",
                .data           = &init_net.sctp.pf_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "pf_expose",
                .data           = &init_net.sctp.pf_expose,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = &pf_expose_max,
        },
};

static int proc_sctp_do_hmac_alg(const struct ctl_table *ctl, int write,
                                 void *buffer, size_t *lenp, loff_t *ppos)
{
        struct net *net = container_of(ctl->data, struct net,
                                       sctp.cookie_auth_enable);
        struct ctl_table tbl;
        char tmp[8] = {0};
        int ret;

        memset(&tbl, 0, sizeof(struct ctl_table));

        if (write) {
                tbl.data = tmp;
                tbl.maxlen = sizeof(tmp) - 1;
                ret = proc_dostring(&tbl, 1, buffer, lenp, ppos);
                if (ret)
                        return ret;
                if (!strcmp(tmp, "sha256")) {
                        net->sctp.cookie_auth_enable = 1;
                        return 0;
                }
                if (!strcmp(tmp, "none")) {
                        net->sctp.cookie_auth_enable = 0;
                        return 0;
                }
                return -EINVAL;
        }
        if (net->sctp.cookie_auth_enable)
                tbl.data = (char *)"sha256";
        else
                tbl.data = (char *)"none";
        tbl.maxlen = strlen(tbl.data);
        return proc_dostring(&tbl, 0, buffer, lenp, ppos);
}

static int proc_sctp_do_rto_min(const struct ctl_table *ctl, int write,
                                void *buffer, size_t *lenp, loff_t *ppos)
{
        struct net *net = container_of(ctl->data, struct net, sctp.rto_min);
        unsigned int min = *(unsigned int *) ctl->extra1;
        unsigned int max = *(unsigned int *) ctl->extra2;
        struct ctl_table tbl;
        int ret, new_value;

        memset(&tbl, 0, sizeof(struct ctl_table));
        tbl.maxlen = sizeof(unsigned int);

        if (write)
                tbl.data = &new_value;
        else
                tbl.data = &net->sctp.rto_min;

        ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
        if (write && ret == 0) {
                if (new_value > max || new_value < min)
                        return -EINVAL;

                net->sctp.rto_min = new_value;
        }

        return ret;
}

static int proc_sctp_do_rto_max(const struct ctl_table *ctl, int write,
                                void *buffer, size_t *lenp, loff_t *ppos)
{
        struct net *net = container_of(ctl->data, struct net, sctp.rto_max);
        unsigned int min = *(unsigned int *) ctl->extra1;
        unsigned int max = *(unsigned int *) ctl->extra2;
        struct ctl_table tbl;
        int ret, new_value;

        memset(&tbl, 0, sizeof(struct ctl_table));
        tbl.maxlen = sizeof(unsigned int);

        if (write)
                tbl.data = &new_value;
        else
                tbl.data = &net->sctp.rto_max;

        ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
        if (write && ret == 0) {
                if (new_value > max || new_value < min)
                        return -EINVAL;

                net->sctp.rto_max = new_value;
        }

        return ret;
}

static int proc_sctp_do_alpha_beta(const struct ctl_table *ctl, int write,
                                   void *buffer, size_t *lenp, loff_t *ppos)
{
        if (write)
                pr_warn_once("Changing rto_alpha or rto_beta may lead to "
                             "suboptimal rtt/srtt estimations!\n");

        return proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
}

static int proc_sctp_do_auth(const struct ctl_table *ctl, int write,
                             void *buffer, size_t *lenp, loff_t *ppos)
{
        struct net *net = container_of(ctl->data, struct net, sctp.auth_enable);
        struct ctl_table tbl;
        int new_value, ret;

        memset(&tbl, 0, sizeof(struct ctl_table));
        tbl.maxlen = sizeof(unsigned int);

        if (write)
                tbl.data = &new_value;
        else
                tbl.data = &net->sctp.auth_enable;

        ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
        if (write && ret == 0) {
                struct sock *sk = net->sctp.ctl_sock;

                net->sctp.auth_enable = new_value;
                /* Update the value in the control socket */
                lock_sock(sk);
                sctp_sk(sk)->ep->auth_enable = new_value;
                release_sock(sk);
        }

        return ret;
}

static DEFINE_MUTEX(sctp_sysctl_mutex);

static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write,
                                 void *buffer, size_t *lenp, loff_t *ppos)
{
        struct net *net = container_of(ctl->data, struct net, sctp.udp_port);
        unsigned int min = *(unsigned int *)ctl->extra1;
        unsigned int max = *(unsigned int *)ctl->extra2;
        struct ctl_table tbl;
        int ret, new_value;

        memset(&tbl, 0, sizeof(struct ctl_table));
        tbl.maxlen = sizeof(unsigned int);

        if (write)
                tbl.data = &new_value;
        else
                tbl.data = &net->sctp.udp_port;

        ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
        if (write && ret == 0) {
                struct sock *sk = net->sctp.ctl_sock;

                if (new_value > max || new_value < min)
                        return -EINVAL;

                mutex_lock(&sctp_sysctl_mutex);
                net->sctp.udp_port = new_value;
                sctp_udp_sock_stop(net);
                if (new_value) {
                        ret = sctp_udp_sock_start(net);
                        if (ret)
                                net->sctp.udp_port = 0;
                }

                /* Update the value in the control socket */
                lock_sock(sk);
                sctp_sk(sk)->udp_port = htons(net->sctp.udp_port);
                release_sock(sk);
                mutex_unlock(&sctp_sysctl_mutex);
        }

        return ret;
}

static int proc_sctp_do_probe_interval(const struct ctl_table *ctl, int write,
                                       void *buffer, size_t *lenp, loff_t *ppos)
{
        struct net *net = container_of(ctl->data, struct net,
                                       sctp.probe_interval);
        struct ctl_table tbl;
        int ret, new_value;

        memset(&tbl, 0, sizeof(struct ctl_table));
        tbl.maxlen = sizeof(unsigned int);

        if (write)
                tbl.data = &new_value;
        else
                tbl.data = &net->sctp.probe_interval;

        ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
        if (write && ret == 0) {
                if (new_value && new_value < SCTP_PROBE_TIMER_MIN)
                        return -EINVAL;

                net->sctp.probe_interval = new_value;
        }

        return ret;
}

int sctp_sysctl_net_register(struct net *net)
{
        size_t table_size = ARRAY_SIZE(sctp_net_table);
        struct ctl_table *table;
        int i;

        table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
        if (!table)
                return -ENOMEM;

        for (i = 0; i < table_size; i++)
                table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;

        table[SCTP_RTO_MIN_IDX].extra2 = &net->sctp.rto_max;
        table[SCTP_RTO_MAX_IDX].extra1 = &net->sctp.rto_min;
        table[SCTP_PF_RETRANS_IDX].extra2 = &net->sctp.ps_retrans;
        table[SCTP_PS_RETRANS_IDX].extra1 = &net->sctp.pf_retrans;

        net->sctp.sysctl_header = register_net_sysctl_sz(net, "net/sctp",
                                                         table, table_size);
        if (net->sctp.sysctl_header == NULL) {
                kfree(table);
                return -ENOMEM;
        }
        return 0;
}

void sctp_sysctl_net_unregister(struct net *net)
{
        struct ctl_table_header *header = net->sctp.sysctl_header;
        const struct ctl_table *table;

        if (!header)
                return;

        table = header->ctl_table_arg;
        unregister_net_sysctl_table(header);
        kfree(table);
        net->sctp.sysctl_header = NULL;
}

static struct ctl_table_header *sctp_sysctl_header;

/* Sysctl registration.  */
void sctp_sysctl_register(void)
{
        sctp_sysctl_header = register_net_sysctl(&init_net, "net/sctp", sctp_table);
}

/* Sysctl deregistration.  */
void sctp_sysctl_unregister(void)
{
        unregister_net_sysctl_table(sctp_sysctl_header);
}