text: /*
   * sysctl_net_ipv4.c: sysctl interface to net IPV4 subsystem.
   *
   * Begun April 1, 1996, Mike Shaver.
   * Added /proc/sys/net/ipv4 directory entry (empty =) ). [MS]
   */
  
  #include <linux/mm.h>
  #include <linux/module.h>
  #include <linux/sysctl.h>
  #include <linux/igmp.h>
  #include <linux/inetdevice.h>
  #include <linux/seqlock.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/nsproxy.h>
  #include <linux/swap.h>
  #include <net/snmp.h>
  #include <net/icmp.h>
  #include <net/ip.h>
  #include <net/route.h>
  #include <net/tcp.h>
  #include <net/udp.h>
  #include <net/cipso_ipv4.h>
  #include <net/inet_frag.h>
  #include <net/ping.h>
  #include <net/tcp_memcontrol.h>
  
  static int zero;
  static int one = 1;
  static int four = 4;
  static int gso_max_segs = GSO_MAX_SEGS;
  static int tcp_retr1_max = 255;
  static int ip_local_port_range_min[] = { 1, 1 };
  static int ip_local_port_range_max[] = { 65535, 65535 };
  static int tcp_adv_win_scale_min = -31;
  static int tcp_adv_win_scale_max = 31;
  static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;
  static int tcp_min_snd_mss_max = 65535;
  static int ip_ttl_min = 1;
  static int ip_ttl_max = 255;
  static int tcp_syn_retries_min = 1;
  static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
  static int ip_ping_group_range_min[] = { 0, 0 };
  static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
  static int tcp_delack_seg_min = TCP_DELACK_MIN;
  static int tcp_delack_seg_max = 60;
  static int tcp_use_userconfig_min;
  static int tcp_use_userconfig_max = 1;
  
  /* Update system visible IP port range */
  static void set_local_port_range(struct net *net, int range[2])
  {
  	write_seqlock_bh(&net->ipv4.ip_local_ports.lock);
  	net->ipv4.ip_local_ports.range[0] = range[0];
  	net->ipv4.ip_local_ports.range[1] = range[1];
  	write_sequnlock_bh(&net->ipv4.ip_local_ports.lock);
  }
  
  /* Validate changes from /proc interface. */
  static int ipv4_local_port_range(struct ctl_table *table, int write,
  				 void __user *buffer,
  				 size_t *lenp, loff_t *ppos)
  {
  	struct net *net =
  		container_of(table->data, struct net, ipv4.ip_local_ports.range);
  	int ret;
  	int range[2];
  	struct ctl_table tmp = {
  		.data = &range,
  		.maxlen = sizeof(range),
  		.mode = table->mode,
  		.extra1 = &ip_local_port_range_min,
  		.extra2 = &ip_local_port_range_max,
  	};
  
  	inet_get_local_port_range(net, &range[0], &range[1]);
  
  	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
  
  	if (write && ret == 0) {
  		if (range[1] < range[0])
  			ret = -EINVAL;
  		else
  			set_local_port_range(net, range);
  	}
  
  	return ret;
  }
  
  
  static void inet_get_ping_group_range_table(struct ctl_table *table, kgid_t *low, kgid_t *high)
  {
  	kgid_t *data = table->data;
  	struct net *net =
  		container_of(table->data, struct net, ipv4.ping_group_range.range);
  	unsigned int seq;
  	do {
  		seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
  
  		*low = data[0];
  		*high = data[1];
  	} while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
  }
  
  /* Update system visible IP port range */
  static void set_ping_group_range(struct ctl_table *table, kgid_t low, kgid_t high)
  {
  	kgid_t *data = table->data;
  	struct net *net =
  		container_of(table->data, struct net, ipv4.ping_group_range.range);
  	write_seqlock_bh(&net->ipv4.ip_local_ports.lock);
  	data[0] = low;
  	data[1] = high;
  	write_sequnlock_bh(&net->ipv4.ip_local_ports.lock);
  }
  
  /* Validate changes from /proc interface. */
  static int ipv4_ping_group_range(struct ctl_table *table, int write,
  				 void __user *buffer,
  				 size_t *lenp, loff_t *ppos)
  {
  	struct user_namespace *user_ns = current_user_ns();
  	int ret;
  	gid_t urange[2];
  	kgid_t low, high;
  	struct ctl_table tmp = {
  		.data = &urange,
  		.maxlen = sizeof(urange),
  		.mode = table->mode,
  		.extra1 = &ip_ping_group_range_min,
  		.extra2 = &ip_ping_group_range_max,
  	};
  
  	inet_get_ping_group_range_table(table, &low, &high);
  	urange[0] = from_kgid_munged(user_ns, low);
  	urange[1] = from_kgid_munged(user_ns, high);
  	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
  
  	if (write && ret == 0) {
  		low = make_kgid(user_ns, urange[0]);
  		high = make_kgid(user_ns, urange[1]);
  		if (!gid_valid(low) || !gid_valid(high))
  			return -EINVAL;
  		if (urange[1] < urange[0] || gid_lt(high, low)) {
  			low = make_kgid(&init_user_ns, 1);
  			high = make_kgid(&init_user_ns, 0);
  		}
  		set_ping_group_range(table, low, high);
  	}
  
  	return ret;
  }
  
  /* Validate changes from /proc interface. */
  static int proc_tcp_default_init_rwnd(struct ctl_table *ctl, int write,
  				      void __user *buffer,
  				      size_t *lenp, loff_t *ppos)
  {
  	int old_value = *(int *)ctl->data;
  	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
  	int new_value = *(int *)ctl->data;
  
  	if (write && ret == 0 && (new_value < 3 || new_value > 100))
  		*(int *)ctl->data = old_value;
  
  	return ret;
  }
  
  static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
  				       void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	char val[TCP_CA_NAME_MAX];
  	struct ctl_table tbl = {
  		.data = val,
  		.maxlen = TCP_CA_NAME_MAX,
  	};
  	int ret;
  
  	tcp_get_default_congestion_control(val);
  
  	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
  	if (write && ret == 0)
  		ret = tcp_set_default_congestion_control(val);
  	return ret;
  }
  
  static int proc_tcp_available_congestion_control(struct ctl_table *ctl,
  						 int write,
  						 void __user *buffer, size_t *lenp,
  						 loff_t *ppos)
  {
  	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX, };
  	int ret;
  
  	tbl.data = kmalloc(tbl.maxlen, GFP_USER);
  	if (!tbl.data)
  		return -ENOMEM;
  	tcp_get_available_congestion_control(tbl.data, TCP_CA_BUF_MAX);
  	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
  	kfree(tbl.data);
  	return ret;
  }
  
  static int proc_allowed_congestion_control(struct ctl_table *ctl,
  					   int write,
  					   void __user *buffer, size_t *lenp,
  					   loff_t *ppos)
  {
  	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX };
  	int ret;
  
  	tbl.data = kmalloc(tbl.maxlen, GFP_USER);
  	if (!tbl.data)
  		return -ENOMEM;
  
  	tcp_get_allowed_congestion_control(tbl.data, tbl.maxlen);
  	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
  	if (write && ret == 0)
  		ret = tcp_set_allowed_congestion_control(tbl.data);
  	kfree(tbl.data);
  	return ret;
  }
  
  static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write,
  				 void __user *buffer, size_t *lenp,
  				 loff_t *ppos)
  {
  	struct ctl_table tbl = { .maxlen = (TCP_FASTOPEN_KEY_LENGTH * 2 + 10) };
  	struct tcp_fastopen_context *ctxt;
  	u32  user_key[4]; /* 16 bytes, matching TCP_FASTOPEN_KEY_LENGTH */
  	__le32 key[4];
  	int ret, i;
  
  	tbl.data = kmalloc(tbl.maxlen, GFP_KERNEL);
  	if (!tbl.data)
  		return -ENOMEM;
  
  	rcu_read_lock();
  	ctxt = rcu_dereference(tcp_fastopen_ctx);
  	if (ctxt)
  		memcpy(key, ctxt->key, TCP_FASTOPEN_KEY_LENGTH);
  	else
  		memset(key, 0, sizeof(key));
  	rcu_read_unlock();
  
  	for (i = 0; i < ARRAY_SIZE(key); i++)
  		user_key[i] = le32_to_cpu(key[i]);
  
  	snprintf(tbl.data, tbl.maxlen, "%08x-%08x-%08x-%08x",
  		user_key[0], user_key[1], user_key[2], user_key[3]);
  	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
  
  	if (write && ret == 0) {
  		if (sscanf(tbl.data, "%x-%x-%x-%x", user_key, user_key + 1,
  			   user_key + 2, user_key + 3) != 4) {
  			ret = -EINVAL;
  			goto bad_key;
  		}
  		/* Generate a dummy secret but don't publish it. This
  		 * is needed so we don't regenerate a new key on the
  		 * first invocation of tcp_fastopen_cookie_gen
  		 */
  		tcp_fastopen_init_key_once(false);
  
  		for (i = 0; i < ARRAY_SIZE(user_key); i++)
  			key[i] = cpu_to_le32(user_key[i]);
  
  		tcp_fastopen_reset_cipher(key, TCP_FASTOPEN_KEY_LENGTH);
  	}
  
  bad_key:
  	pr_debug("proc FO key set 0x%x-%x-%x-%x <- 0x%s: %u\n",
  		 user_key[0], user_key[1], user_key[2], user_key[3],
  	       (char *)tbl.data, ret);
  	kfree(tbl.data);
  	return ret;
  }
  
  #ifdef CONFIG_NETPM
  #define TCP_NETPM_IFNAME_MAX	23
  #define TCP_NETPM_IFDEVS_MAX	64
  
  static int proc_netpm_ifdevs(struct ctl_table *ctl, int write,
  			     void __user *buffer, size_t *lenp,
  			     loff_t *ppos)
  {
  	size_t offs = 0;
  	char ifname[TCP_NETPM_IFNAME_MAX + 1];
  	char *strbuf = NULL;
  	struct net_device *dev;
  	struct ctl_table tbl = { .maxlen = ((TCP_NETPM_IFNAME_MAX + 1) * TCP_NETPM_IFDEVS_MAX) };
  	int ret = 0;
  
  	if (!write) {
  		char *dev_list;
  		int len = tbl.maxlen, used;
  
  		tbl.data = kzalloc(tbl.maxlen, GFP_KERNEL);
  		if (!tbl.data)
  			return -ENOMEM;
  		dev_list = (char *)tbl.data;
  
  		rcu_read_lock();
  		for_each_netdev_rcu(&init_net, dev) {
  			if (dev && dev->netpm_use) {
  				used = snprintf(dev_list, len, "%s ", dev->name);
  				dev_list += used;
  				len -= used;
  			}
  		}
  		rcu_read_unlock();
  
  		ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
  
  		kfree(tbl.data);
  		return ret;
  	}
  
  	if (*lenp > tbl.maxlen || *lenp < 1) {
  		pr_info("%s: netpm: lenp=%lu\n", __func__, *lenp);
  		return -EINVAL;
  	}
  
  	strbuf = kzalloc(*lenp + 1, GFP_USER);
  	if (!strbuf)
  		return -ENOMEM;
  
  	if (copy_from_user(strbuf, buffer, *lenp)) {
  		kfree(strbuf);
  		return -EFAULT;
  	}
  
  	/* clear netpm use */
  	rcu_read_lock();
  	for_each_netdev_rcu(&init_net, dev) {
  		if (dev)
  			dev->netpm_use = 0;
  	}
  	rcu_read_unlock();
  
  	while (offs < *lenp && sscanf(strbuf + offs, "%23s", ifname) > 0) {
  		struct net_device *dev;
  		int len = strlen(ifname);
  
  		if (!len)
  			break;
  
  		rcu_read_lock();
  		dev = dev_get_by_name_rcu(&init_net, ifname);
  		if (dev) {
  			dev->netpm_use = 1;
  			pr_info("%s: netpm: ifdev %s added\n", __func__, ifname);
  		}
  		rcu_read_unlock();
  
  		offs += len;
  		while (offs < *lenp && ((char *)strbuf)[offs] == ' ')
  			offs++;
  	}
  
  	kfree(strbuf);
  	return 0;
  }
  #endif
  
  static struct ctl_table ipv4_table[] = {
  	{
  		.procname	= "tcp_timestamps",
  		.data		= &sysctl_tcp_timestamps,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_window_scaling",
  		.data		= &sysctl_tcp_window_scaling,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_sack",
  		.data		= &sysctl_tcp_sack,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_retrans_collapse",
  		.data		= &sysctl_tcp_retrans_collapse,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ip_default_ttl",
  		.data		= &sysctl_ip_default_ttl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &ip_ttl_min,
  		.extra2		= &ip_ttl_max,
  	},
  	{
  		.procname	= "tcp_syn_retries",
  		.data		= &sysctl_tcp_syn_retries,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &tcp_syn_retries_min,
  		.extra2		= &tcp_syn_retries_max
  	},
  	{
  		.procname	= "tcp_synack_retries",
  		.data		= &sysctl_tcp_synack_retries,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_max_orphans",
  		.data		= &sysctl_tcp_max_orphans,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_max_tw_buckets",
  		.data		= &tcp_death_row.sysctl_max_tw_buckets,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ip_early_demux",
  		.data		= &sysctl_ip_early_demux,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ip_dynaddr",
  		.data		= &sysctl_ip_dynaddr,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_keepalive_time",
  		.data		= &sysctl_tcp_keepalive_time,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "tcp_keepalive_probes",
  		.data		= &sysctl_tcp_keepalive_probes,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_keepalive_intvl",
  		.data		= &sysctl_tcp_keepalive_intvl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "tcp_retries1",
  		.data		= &sysctl_tcp_retries1,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra2		= &tcp_retr1_max
  	},
  	{
  		.procname	= "tcp_retries2",
  		.data		= &sysctl_tcp_retries2,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_fin_timeout",
  		.data		= &sysctl_tcp_fin_timeout,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  #ifdef CONFIG_SYN_COOKIES
  	{
  		.procname	= "tcp_syncookies",
  		.data		= &sysctl_tcp_syncookies,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #endif
  	{
  		.procname	= "tcp_fastopen",
  		.data		= &sysctl_tcp_fastopen,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_fastopen_key",
  		.mode		= 0600,
  		.maxlen		= ((TCP_FASTOPEN_KEY_LENGTH * 2) + 10),
  		.proc_handler	= proc_tcp_fastopen_key,
  	},
  	{
  		.procname	= "tcp_tw_recycle",
  		.data		= &tcp_death_row.sysctl_tw_recycle,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_abort_on_overflow",
  		.data		= &sysctl_tcp_abort_on_overflow,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_stdurg",
  		.data		= &sysctl_tcp_stdurg,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_rfc1337",
  		.data		= &sysctl_tcp_rfc1337,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_max_syn_backlog",
  		.data		= &sysctl_max_syn_backlog,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "igmp_max_memberships",
  		.data		= &sysctl_igmp_max_memberships,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "igmp_max_msf",
  		.data		= &sysctl_igmp_max_msf,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #ifdef CONFIG_IP_MULTICAST
  	{
  		.procname	= "igmp_qrv",
  		.data		= &sysctl_igmp_qrv,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &one
  	},
  #endif
  	{
  		.procname	= "inet_peer_threshold",
  		.data		= &inet_peer_threshold,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "inet_peer_minttl",
  		.data		= &inet_peer_minttl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "inet_peer_maxttl",
  		.data		= &inet_peer_maxttl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "tcp_orphan_retries",
  		.data		= &sysctl_tcp_orphan_retries,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_fack",
  		.data		= &sysctl_tcp_fack,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_reordering",
  		.data		= &sysctl_tcp_reordering,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_dsack",
  		.data		= &sysctl_tcp_dsack,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_mem",
  		.maxlen		= sizeof(sysctl_tcp_mem),
  		.data		= &sysctl_tcp_mem,
  		.mode		= 0644,
  		.proc_handler	= proc_doulongvec_minmax,
  	},
  	{
  		.procname	= "tcp_wmem",
  		.data		= &sysctl_tcp_wmem,
  		.maxlen		= sizeof(sysctl_tcp_wmem),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &one,
  	},
  	{
  		.procname	= "tcp_notsent_lowat",
  		.data		= &sysctl_tcp_notsent_lowat,
  		.maxlen		= sizeof(sysctl_tcp_notsent_lowat),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_rmem",
  		.data		= &sysctl_tcp_rmem,
  		.maxlen		= sizeof(sysctl_tcp_rmem),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &one,
  	},
  	{
  		.procname	= "tcp_app_win",
  		.data		= &sysctl_tcp_app_win,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_adv_win_scale",
  		.data		= &sysctl_tcp_adv_win_scale,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &tcp_adv_win_scale_min,
  		.extra2		= &tcp_adv_win_scale_max,
  	},
  	{
  		.procname	= "tcp_tw_reuse",
  		.data		= &sysctl_tcp_tw_reuse,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_frto",
  		.data		= &sysctl_tcp_frto,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_low_latency",
  		.data		= &sysctl_tcp_low_latency,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_no_metrics_save",
  		.data		= &sysctl_tcp_nometrics_save,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_moderate_rcvbuf",
  		.data		= &sysctl_tcp_moderate_rcvbuf,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_tso_win_divisor",
  		.data		= &sysctl_tcp_tso_win_divisor,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_congestion_control",
  		.mode		= 0644,
  		.maxlen		= TCP_CA_NAME_MAX,
  		.proc_handler	= proc_tcp_congestion_control,
  	},
  	{
  		.procname	= "tcp_mtu_probing",
  		.data		= &sysctl_tcp_mtu_probing,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_base_mss",
  		.data		= &sysctl_tcp_base_mss,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_workaround_signed_windows",
  		.data		= &sysctl_tcp_workaround_signed_windows,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_limit_output_bytes",
  		.data		= &sysctl_tcp_limit_output_bytes,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_challenge_ack_limit",
  		.data		= &sysctl_tcp_challenge_ack_limit,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_slow_start_after_idle",
  		.data		= &sysctl_tcp_slow_start_after_idle,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #ifdef CONFIG_NETPM
  	{
  		.procname	= "tcp_netpm",
  		.data		= &sysctl_tcp_netpm,
  		.maxlen		= sizeof(sysctl_tcp_netpm),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "tcp_netpm_ifdevs",
  		.maxlen		= ((TCP_NETPM_IFNAME_MAX + 1) * TCP_NETPM_IFDEVS_MAX),
  		.mode		= 0644,
  		.proc_handler	= proc_netpm_ifdevs
  	},
  #endif
  #ifdef CONFIG_NETLABEL
  	{
  		.procname	= "cipso_cache_enable",
  		.data		= &cipso_v4_cache_enabled,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "cipso_cache_bucket_size",
  		.data		= &cipso_v4_cache_bucketsize,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "cipso_rbm_optfmt",
  		.data		= &cipso_v4_rbm_optfmt,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "cipso_rbm_strictvalid",
  		.data		= &cipso_v4_rbm_strictvalid,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #endif /* CONFIG_NETLABEL */
  	{
  		.procname	= "tcp_available_congestion_control",
  		.maxlen		= TCP_CA_BUF_MAX,
  		.mode		= 0444,
  		.proc_handler   = proc_tcp_available_congestion_control,
  	},
  	{
  		.procname	= "tcp_allowed_congestion_control",
  		.maxlen		= TCP_CA_BUF_MAX,
  		.mode		= 0644,
  		.proc_handler   = proc_allowed_congestion_control,
  	},
  	{
  		.procname       = "tcp_thin_linear_timeouts",
  		.data           = &sysctl_tcp_thin_linear_timeouts,
  		.maxlen         = sizeof(int),
  		.mode           = 0644,
  		.proc_handler   = proc_dointvec
  	},
  	{
  		.procname       = "tcp_thin_dupack",
  		.data           = &sysctl_tcp_thin_dupack,
  		.maxlen         = sizeof(int),
  		.mode           = 0644,
  		.proc_handler   = proc_dointvec
  	},
  	{
  		.procname	= "tcp_early_retrans",
  		.data		= &sysctl_tcp_early_retrans,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &zero,
  		.extra2		= &four,
  	},
  	{
  		.procname	= "tcp_min_tso_segs",
  		.data		= &sysctl_tcp_min_tso_segs,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &zero,
  		.extra2		= &gso_max_segs,
  	},
  	{
  		.procname	= "tcp_autocorking",
  		.data		= &sysctl_tcp_autocorking,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &zero,
  		.extra2		= &one,
  	},
  	{
  		.procname       = "tcp_default_init_rwnd",
  		.data           = &sysctl_tcp_default_init_rwnd,
  		.maxlen         = sizeof(int),
  		.mode           = 0644,
  		.proc_handler   = proc_tcp_default_init_rwnd
  	},
  	{
  		.procname	= "icmp_msgs_per_sec",
  		.data		= &sysctl_icmp_msgs_per_sec,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &zero,
  	},
  	{
  		.procname	= "icmp_msgs_burst",
  		.data		= &sysctl_icmp_msgs_burst,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &zero,
  	},
  	{
  		.procname	= "udp_mem",
  		.data		= &sysctl_udp_mem,
  		.maxlen		= sizeof(sysctl_udp_mem),
  		.mode		= 0644,
  		.proc_handler	= proc_doulongvec_minmax,
  	},
  	{
  		.procname	= "udp_rmem_min",
  		.data		= &sysctl_udp_rmem_min,
  		.maxlen		= sizeof(sysctl_udp_rmem_min),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &one
  	},
  	{
  		.procname	= "udp_wmem_min",
  		.data		= &sysctl_udp_wmem_min,
  		.maxlen		= sizeof(sysctl_udp_wmem_min),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &one
  	},
  	{
  		.procname	= "tcp_delack_seg",
  		.data		= &sysctl_tcp_delack_seg,
  		.maxlen		= sizeof(sysctl_tcp_delack_seg),
  		.mode		= 0644,
  		.proc_handler	= tcp_proc_delayed_ack_control,
  		.extra1		= &tcp_delack_seg_min,
  		.extra2		= &tcp_delack_seg_max,
  	},
  	{
  		.procname       = "tcp_use_userconfig",
  		.data           = &sysctl_tcp_use_userconfig,
  		.maxlen         = sizeof(sysctl_tcp_use_userconfig),
  		.mode           = 0644,
  		.proc_handler   = tcp_use_userconfig_sysctl_handler,
  		.extra1		= &tcp_use_userconfig_min,
  		.extra2		= &tcp_use_userconfig_max,
  	},
  
  	{ }
  };
  
  static struct ctl_table ipv4_net_table[] = {
  	{
  		.procname	= "icmp_echo_ignore_all",
  		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_all,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "icmp_echo_ignore_broadcasts",
  		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "icmp_ignore_bogus_error_responses",
  		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "icmp_errors_use_inbound_ifaddr",
  		.data		= &init_net.ipv4.sysctl_icmp_errors_use_inbound_ifaddr,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "icmp_ratelimit",
  		.data		= &init_net.ipv4.sysctl_icmp_ratelimit,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_ms_jiffies,
  	},
  	{
  		.procname	= "icmp_ratemask",
  		.data		= &init_net.ipv4.sysctl_icmp_ratemask,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ping_group_range",
  		.data		= &init_net.ipv4.ping_group_range.range,
  		.maxlen		= sizeof(gid_t)*2,
  		.mode		= 0644,
  		.proc_handler	= ipv4_ping_group_range,
  	},
  	{
  		.procname	= "tcp_ecn",
  		.data		= &init_net.ipv4.sysctl_tcp_ecn,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ip_local_port_range",
  		.maxlen		= sizeof(init_net.ipv4.ip_local_ports.range),
  		.data		= &init_net.ipv4.ip_local_ports.range,
  		.mode		= 0644,
  		.proc_handler	= ipv4_local_port_range,
  	},
  	{
  		.procname	= "ip_local_reserved_ports",
  		.data		= &init_net.ipv4.sysctl_local_reserved_ports,
  		.maxlen		= 65536,
  		.mode		= 0644,
  		.proc_handler	= proc_do_large_bitmap,
  	},
  	{
  		.procname	= "ip_no_pmtu_disc",
  		.data		= &init_net.ipv4.sysctl_ip_no_pmtu_disc,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ip_forward_use_pmtu",
  		.data		= &init_net.ipv4.sysctl_ip_fwd_use_pmtu,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "ip_nonlocal_bind",
  		.data		= &init_net.ipv4.sysctl_ip_nonlocal_bind,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "fwmark_reflect",
  		.data		= &init_net.ipv4.sysctl_fwmark_reflect,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "tcp_min_snd_mss",
  		.data		= &init_net.ipv4.sysctl_tcp_min_snd_mss,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &tcp_min_snd_mss_min,
  		.extra2		= &tcp_min_snd_mss_max,
  	},
  	{
  		.procname	= "tcp_fwmark_accept",
  		.data		= &init_net.ipv4.sysctl_tcp_fwmark_accept,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{ }
  };
  
  static __net_init int ipv4_sysctl_init_net(struct net *net)
  {
  	struct ctl_table *table;
  
  	table = ipv4_net_table;
  	if (!net_eq(net, &init_net)) {
  		int i;
  
  		table = kmemdup(table, sizeof(ipv4_net_table), GFP_KERNEL);
  		if (table == NULL)
  			goto err_alloc;
  
  		/* Update the variables to point into the current struct net */
  		for (i = 0; i < ARRAY_SIZE(ipv4_net_table) - 1; i++)
  			table[i].data += (void *)net - (void *)&init_net;
  	}
  
  	net->ipv4.ipv4_hdr = register_net_sysctl(net, "net/ipv4", table);
  	if (net->ipv4.ipv4_hdr == NULL)
  		goto err_reg;
  
  	net->ipv4.sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL);
  	if (!net->ipv4.sysctl_local_reserved_ports)
  		goto err_ports;
  
  	return 0;
  
  err_ports:
  	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
  err_reg:
  	if (!net_eq(net, &init_net))
  		kfree(table);
  err_alloc:
  	return -ENOMEM;
  }
  
  static __net_exit void ipv4_sysctl_exit_net(struct net *net)
  {
  	struct ctl_table *table;
  
  	kfree(net->ipv4.sysctl_local_reserved_ports);
  	table = net->ipv4.ipv4_hdr->ctl_table_arg;
  	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
  	kfree(table);
  }
  
  static __net_initdata struct pernet_operations ipv4_sysctl_ops = {
  	.init = ipv4_sysctl_init_net,
  	.exit = ipv4_sysctl_exit_net,
  };
  
  static __init int sysctl_ipv4_init(void)
  {
  	struct ctl_table_header *hdr;
  
  	hdr = register_net_sysctl(&init_net, "net/ipv4", ipv4_table);
  	if (hdr == NULL)
  		return -ENOMEM;
  
  	if (register_pernet_subsys(&ipv4_sysctl_ops)) {
  		unregister_net_sysctl_table(hdr);
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  __initcall(sysctl_ipv4_init);
  