// 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 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(struct ctl_table *ctl, int write,

  				void __user *buffer, size_t *lenp,

  				loff_t *ppos);

  static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
  				void __user *buffer, size_t *lenp,
  				loff_t *ppos);
  static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,

  				void __user *buffer, size_t *lenp,

  				loff_t *ppos);

  static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
  				   void __user *buffer, size_t *lenp,
  				   loff_t *ppos);

  static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
  			     void __user *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,
  	},
  
  	{ /* sentinel */ }
  };

  static struct ctl_table sctp_net_table[] = {

  	{

  		.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_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

  	},
  	{

  		.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

  	},
  	{

  		.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.sctp_hmac_alg,

  		.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	= "pf_retrans",
  		.data		= &init_net.sctp.pf_retrans,
  		.maxlen		= sizeof(int),

  		.mode		= 0644,

  		.proc_handler	= proc_dointvec_minmax,

  		.extra1		= SYSCTL_ZERO,
  		.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	= "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,
  	},

  	{
  		.procname	= "pf_enable",
  		.data		= &init_net.sctp.pf_enable,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},

  	{ /* sentinel */ }

  };

  static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,

  				void __user *buffer, size_t *lenp,
  				loff_t *ppos)
  {
  	struct net *net = current->nsproxy->net_ns;

  	struct ctl_table tbl;

  	bool changed = false;

  	char *none = "none";

  	char tmp[8] = {0};

  	int ret;

  
  	memset(&tbl, 0, sizeof(struct ctl_table));
  
  	if (write) {
  		tbl.data = tmp;

  		tbl.maxlen = sizeof(tmp);

  	} else {
  		tbl.data = net->sctp.sctp_hmac_alg ? : none;
  		tbl.maxlen = strlen(tbl.data);
  	}

  	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
  	if (write && ret == 0) {

  #ifdef CONFIG_CRYPTO_MD5
  		if (!strncmp(tmp, "md5", 3)) {
  			net->sctp.sctp_hmac_alg = "md5";

  			changed = true;

  		}
  #endif
  #ifdef CONFIG_CRYPTO_SHA1
  		if (!strncmp(tmp, "sha1", 4)) {
  			net->sctp.sctp_hmac_alg = "sha1";

  			changed = true;

  		}
  #endif
  		if (!strncmp(tmp, "none", 4)) {
  			net->sctp.sctp_hmac_alg = NULL;

  			changed = true;

  		}

  		if (!changed)
  			ret = -EINVAL;
  	}
  
  	return ret;
  }

  static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
  				void __user *buffer, size_t *lenp,
  				loff_t *ppos)
  {
  	struct net *net = current->nsproxy->net_ns;

  	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(struct ctl_table *ctl, int write,
  				void __user *buffer, size_t *lenp,
  				loff_t *ppos)
  {
  	struct net *net = current->nsproxy->net_ns;

  	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(struct ctl_table *ctl, int write,
  				   void __user *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!
  ");

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

  static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
  			     void __user *buffer, size_t *lenp,
  			     loff_t *ppos)
  {
  	struct net *net = current->nsproxy->net_ns;
  	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;
  }

  int sctp_sysctl_net_register(struct net *net)
  {

  	struct ctl_table *table;
  	int i;

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

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

  	net->sctp.sysctl_header = register_net_sysctl(net, "net/sctp", table);

  	if (net->sctp.sysctl_header == NULL) {
  		kfree(table);
  		return -ENOMEM;
  	}

  	return 0;
  }
  
  void sctp_sysctl_net_unregister(struct net *net)
  {

  	struct ctl_table *table;
  
  	table = net->sctp.sysctl_header->ctl_table_arg;

  	unregister_net_sysctl_table(net->sctp.sysctl_header);

  	kfree(table);

  }

  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);

  }