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 <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>
  
  static int zero;
  static int one = 1;
  static int tcp_retr1_max = 255;
  static int tcp_syn_retries_min = 1;
  static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
  static int ip_local_port_range_min[] = { 1, 1 };
  static int ip_local_port_range_max[] = { 65535, 65535 };
  
  /* Update system visible IP port range */
  static void set_local_port_range(int range[2])
  {
  	write_seqlock(&sysctl_local_ports.lock);
  	sysctl_local_ports.range[0] = range[0];
  	sysctl_local_ports.range[1] = range[1];
  	write_sequnlock(&sysctl_local_ports.lock);
  }
  
  /* Validate changes from /proc interface. */
  static int ipv4_local_port_range(ctl_table *table, int write,
  				 void __user *buffer,
  				 size_t *lenp, loff_t *ppos)
  {
  	int ret;
  	int range[2];
  	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(range, 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(range);
  	}
  
  	return ret;
  }
  
  /* Validate changes from sysctl interface. */
  static int ipv4_sysctl_local_port_range(ctl_table *table,
  					 void __user *oldval,
  					 size_t __user *oldlenp,
  					void __user *newval, size_t newlen)
  {
  	int ret;
  	int range[2];
  	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(range, range + 1);
  	ret = sysctl_intvec(&tmp, oldval, oldlenp, newval, newlen);
  	if (ret == 0 && newval && newlen) {
  		if (range[1] < range[0])
  			ret = -EINVAL;
  		else
  			set_local_port_range(range);
  	}
  	return ret;
  }
  
  
  static int proc_tcp_congestion_control(ctl_table *ctl, int write,
  				       void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	char val[TCP_CA_NAME_MAX];
  	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 sysctl_tcp_congestion_control(ctl_table *table,
  					 void __user *oldval,
  					 size_t __user *oldlenp,
  					 void __user *newval, size_t newlen)
  {
  	char val[TCP_CA_NAME_MAX];
  	ctl_table tbl = {
  		.data = val,
  		.maxlen = TCP_CA_NAME_MAX,
  	};
  	int ret;
  
  	tcp_get_default_congestion_control(val);
  	ret = sysctl_string(&tbl, oldval, oldlenp, newval, newlen);
  	if (ret == 1 && newval && newlen)
  		ret = tcp_set_default_congestion_control(val);
  	return ret;
  }
  
  static int proc_tcp_available_congestion_control(ctl_table *ctl,
  						 int write,
  						 void __user *buffer, size_t *lenp,
  						 loff_t *ppos)
  {
  	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(ctl_table *ctl,
  					   int write,
  					   void __user *buffer, size_t *lenp,
  					   loff_t *ppos)
  {
  	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 strategy_allowed_congestion_control(ctl_table *table,
  					       void __user *oldval,
  					       size_t __user *oldlenp,
  					       void __user *newval,
  					       size_t newlen)
  {
  	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, tbl.maxlen);
  	ret = sysctl_string(&tbl, oldval, oldlenp, newval, newlen);
  	if (ret == 1 && newval && newlen)
  		ret = tcp_set_allowed_congestion_control(tbl.data);
  	kfree(tbl.data);
  
  	return ret;
  
  }
  
  static struct ctl_table ipv4_table[] = {
  	{
  		.ctl_name	= NET_IPV4_TCP_TIMESTAMPS,
  		.procname	= "tcp_timestamps",
  		.data		= &sysctl_tcp_timestamps,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_WINDOW_SCALING,
  		.procname	= "tcp_window_scaling",
  		.data		= &sysctl_tcp_window_scaling,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_SACK,
  		.procname	= "tcp_sack",
  		.data		= &sysctl_tcp_sack,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_RETRANS_COLLAPSE,
  		.procname	= "tcp_retrans_collapse",
  		.data		= &sysctl_tcp_retrans_collapse,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_DEFAULT_TTL,
  		.procname	= "ip_default_ttl",
  		.data		= &sysctl_ip_default_ttl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= ipv4_doint_and_flush,
  		.strategy	= ipv4_doint_and_flush_strategy,
  		.extra2		= &init_net,
  	},
  	{
  		.ctl_name	= NET_IPV4_NO_PMTU_DISC,
  		.procname	= "ip_no_pmtu_disc",
  		.data		= &ipv4_config.no_pmtu_disc,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &tcp_syn_retries_min,
  		.extra2		= &tcp_syn_retries_max,
  		.strategy	= &sysctl_intvec
  	},
  	{
  		.ctl_name	= NET_IPV4_NONLOCAL_BIND,
  		.procname	= "ip_nonlocal_bind",
  		.data		= &sysctl_ip_nonlocal_bind,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_SYN_RETRIES,
  		.procname	= "tcp_syn_retries",
  		.data		= &sysctl_tcp_syn_retries,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_SYNACK_RETRIES,
  		.procname	= "tcp_synack_retries",
  		.data		= &sysctl_tcp_synack_retries,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_MAX_ORPHANS,
  		.procname	= "tcp_max_orphans",
  		.data		= &sysctl_tcp_max_orphans,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_MAX_TW_BUCKETS,
  		.procname	= "tcp_max_tw_buckets",
  		.data		= &tcp_death_row.sysctl_max_tw_buckets,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_DYNADDR,
  		.procname	= "ip_dynaddr",
  		.data		= &sysctl_ip_dynaddr,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_KEEPALIVE_TIME,
  		.procname	= "tcp_keepalive_time",
  		.data		= &sysctl_tcp_keepalive_time,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_KEEPALIVE_PROBES,
  		.procname	= "tcp_keepalive_probes",
  		.data		= &sysctl_tcp_keepalive_probes,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_KEEPALIVE_INTVL,
  		.procname	= "tcp_keepalive_intvl",
  		.data		= &sysctl_tcp_keepalive_intvl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_RETRIES1,
  		.procname	= "tcp_retries1",
  		.data		= &sysctl_tcp_retries1,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.strategy	= sysctl_intvec,
  		.extra2		= &tcp_retr1_max
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_RETRIES2,
  		.procname	= "tcp_retries2",
  		.data		= &sysctl_tcp_retries2,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_FIN_TIMEOUT,
  		.procname	= "tcp_fin_timeout",
  		.data		= &sysctl_tcp_fin_timeout,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  #ifdef CONFIG_SYN_COOKIES
  	{
  		.ctl_name	= NET_TCP_SYNCOOKIES,
  		.procname	= "tcp_syncookies",
  		.data		= &sysctl_tcp_syncookies,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #endif
  	{
  		.ctl_name	= NET_TCP_TW_RECYCLE,
  		.procname	= "tcp_tw_recycle",
  		.data		= &tcp_death_row.sysctl_tw_recycle,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_ABORT_ON_OVERFLOW,
  		.procname	= "tcp_abort_on_overflow",
  		.data		= &sysctl_tcp_abort_on_overflow,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_STDURG,
  		.procname	= "tcp_stdurg",
  		.data		= &sysctl_tcp_stdurg,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_RFC1337,
  		.procname	= "tcp_rfc1337",
  		.data		= &sysctl_tcp_rfc1337,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_MAX_SYN_BACKLOG,
  		.procname	= "tcp_max_syn_backlog",
  		.data		= &sysctl_max_syn_backlog,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_LOCAL_PORT_RANGE,
  		.procname	= "ip_local_port_range",
  		.data		= &sysctl_local_ports.range,
  		.maxlen		= sizeof(sysctl_local_ports.range),
  		.mode		= 0644,
  		.proc_handler	= ipv4_local_port_range,
  		.strategy	= ipv4_sysctl_local_port_range,
  	},
  #ifdef CONFIG_IP_MULTICAST
  	{
  		.ctl_name	= NET_IPV4_IGMP_MAX_MEMBERSHIPS,
  		.procname	= "igmp_max_memberships",
  		.data		= &sysctl_igmp_max_memberships,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  
  #endif
  	{
  		.ctl_name	= NET_IPV4_IGMP_MAX_MSF,
  		.procname	= "igmp_max_msf",
  		.data		= &sysctl_igmp_max_msf,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_INET_PEER_THRESHOLD,
  		.procname	= "inet_peer_threshold",
  		.data		= &inet_peer_threshold,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_INET_PEER_MINTTL,
  		.procname	= "inet_peer_minttl",
  		.data		= &inet_peer_minttl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  	{
  		.ctl_name	= NET_IPV4_INET_PEER_MAXTTL,
  		.procname	= "inet_peer_maxttl",
  		.data		= &inet_peer_maxttl,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  	{
  		.ctl_name	= NET_IPV4_INET_PEER_GC_MINTIME,
  		.procname	= "inet_peer_gc_mintime",
  		.data		= &inet_peer_gc_mintime,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  	{
  		.ctl_name	= NET_IPV4_INET_PEER_GC_MAXTIME,
  		.procname	= "inet_peer_gc_maxtime",
  		.data		= &inet_peer_gc_maxtime,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  		.strategy	= sysctl_jiffies
  	},
  	{
  		.ctl_name	= NET_TCP_ORPHAN_RETRIES,
  		.procname	= "tcp_orphan_retries",
  		.data		= &sysctl_tcp_orphan_retries,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_FACK,
  		.procname	= "tcp_fack",
  		.data		= &sysctl_tcp_fack,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_REORDERING,
  		.procname	= "tcp_reordering",
  		.data		= &sysctl_tcp_reordering,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_ECN,
  		.procname	= "tcp_ecn",
  		.data		= &sysctl_tcp_ecn,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_DSACK,
  		.procname	= "tcp_dsack",
  		.data		= &sysctl_tcp_dsack,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_MEM,
  		.procname	= "tcp_mem",
  		.data		= &sysctl_tcp_mem,
  		.maxlen		= sizeof(sysctl_tcp_mem),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_WMEM,
  		.procname	= "tcp_wmem",
  		.data		= &sysctl_tcp_wmem,
  		.maxlen		= sizeof(sysctl_tcp_wmem),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.strategy	= sysctl_intvec,
  		.extra1		= &one,
  	},
  	{
  		.ctl_name	= NET_TCP_RMEM,
  		.procname	= "tcp_rmem",
  		.data		= &sysctl_tcp_rmem,
  		.maxlen		= sizeof(sysctl_tcp_rmem),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.strategy	= sysctl_intvec,
  		.extra1		= &one,
  	},
  	{
  		.ctl_name	= NET_TCP_APP_WIN,
  		.procname	= "tcp_app_win",
  		.data		= &sysctl_tcp_app_win,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_ADV_WIN_SCALE,
  		.procname	= "tcp_adv_win_scale",
  		.data		= &sysctl_tcp_adv_win_scale,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_TW_REUSE,
  		.procname	= "tcp_tw_reuse",
  		.data		= &sysctl_tcp_tw_reuse,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_FRTO,
  		.procname	= "tcp_frto",
  		.data		= &sysctl_tcp_frto,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_FRTO_RESPONSE,
  		.procname	= "tcp_frto_response",
  		.data		= &sysctl_tcp_frto_response,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_LOW_LATENCY,
  		.procname	= "tcp_low_latency",
  		.data		= &sysctl_tcp_low_latency,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_TCP_NO_METRICS_SAVE,
  		.procname	= "tcp_no_metrics_save",
  		.data		= &sysctl_tcp_nometrics_save,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_TCP_MODERATE_RCVBUF,
  		.procname	= "tcp_moderate_rcvbuf",
  		.data		= &sysctl_tcp_moderate_rcvbuf,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_TCP_TSO_WIN_DIVISOR,
  		.procname	= "tcp_tso_win_divisor",
  		.data		= &sysctl_tcp_tso_win_divisor,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_TCP_CONG_CONTROL,
  		.procname	= "tcp_congestion_control",
  		.mode		= 0644,
  		.maxlen		= TCP_CA_NAME_MAX,
  		.proc_handler	= proc_tcp_congestion_control,
  		.strategy	= sysctl_tcp_congestion_control,
  	},
  	{
  		.ctl_name	= NET_TCP_ABC,
  		.procname	= "tcp_abc",
  		.data		= &sysctl_tcp_abc,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_TCP_MTU_PROBING,
  		.procname	= "tcp_mtu_probing",
  		.data		= &sysctl_tcp_mtu_probing,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_TCP_BASE_MSS,
  		.procname	= "tcp_base_mss",
  		.data		= &sysctl_tcp_base_mss,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_IPV4_TCP_WORKAROUND_SIGNED_WINDOWS,
  		.procname	= "tcp_workaround_signed_windows",
  		.data		= &sysctl_tcp_workaround_signed_windows,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #ifdef CONFIG_NET_DMA
  	{
  		.ctl_name	= NET_TCP_DMA_COPYBREAK,
  		.procname	= "tcp_dma_copybreak",
  		.data		= &sysctl_tcp_dma_copybreak,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #endif
  	{
  		.ctl_name	= NET_TCP_SLOW_START_AFTER_IDLE,
  		.procname	= "tcp_slow_start_after_idle",
  		.data		= &sysctl_tcp_slow_start_after_idle,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #ifdef CONFIG_NETLABEL
  	{
  		.ctl_name	= NET_CIPSOV4_CACHE_ENABLE,
  		.procname	= "cipso_cache_enable",
  		.data		= &cipso_v4_cache_enabled,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_CIPSOV4_CACHE_BUCKET_SIZE,
  		.procname	= "cipso_cache_bucket_size",
  		.data		= &cipso_v4_cache_bucketsize,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_CIPSOV4_RBM_OPTFMT,
  		.procname	= "cipso_rbm_optfmt",
  		.data		= &cipso_v4_rbm_optfmt,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= NET_CIPSOV4_RBM_STRICTVALID,
  		.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,
  	},
  	{
  		.ctl_name	= NET_TCP_ALLOWED_CONG_CONTROL,
  		.procname	= "tcp_allowed_congestion_control",
  		.maxlen		= TCP_CA_BUF_MAX,
  		.mode		= 0644,
  		.proc_handler   = proc_allowed_congestion_control,
  		.strategy	= strategy_allowed_congestion_control,
  	},
  	{
  		.ctl_name	= NET_TCP_MAX_SSTHRESH,
  		.procname	= "tcp_max_ssthresh",
  		.data		= &sysctl_tcp_max_ssthresh,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.ctl_name	= CTL_UNNUMBERED,
  		.procname	= "udp_mem",
  		.data		= &sysctl_udp_mem,
  		.maxlen		= sizeof(sysctl_udp_mem),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.strategy	= sysctl_intvec,
  		.extra1		= &zero
  	},
  	{
  		.ctl_name	= CTL_UNNUMBERED,
  		.procname	= "udp_rmem_min",
  		.data		= &sysctl_udp_rmem_min,
  		.maxlen		= sizeof(sysctl_udp_rmem_min),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.strategy	= sysctl_intvec,
  		.extra1		= &one
  	},
  	{
  		.ctl_name	= CTL_UNNUMBERED,
  		.procname	= "udp_wmem_min",
  		.data		= &sysctl_udp_wmem_min,
  		.maxlen		= sizeof(sysctl_udp_wmem_min),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.strategy	= sysctl_intvec,
  		.extra1		= &one
  	},
  	{ .ctl_name = 0 }
  };
  
  static struct ctl_table ipv4_net_table[] = {
  	{
  		.ctl_name	= NET_IPV4_ICMP_ECHO_IGNORE_ALL,
  		.procname	= "icmp_echo_ignore_all",
  		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_all,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_ICMP_ECHO_IGNORE_BROADCASTS,
  		.procname	= "icmp_echo_ignore_broadcasts",
  		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= NET_IPV4_ICMP_IGNORE_BOGUS_ERROR_RESPONSES,
  		.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
  	},
  	{
  		.ctl_name	= NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR,
  		.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
  	},
  	{
  		.ctl_name	= NET_IPV4_ICMP_RATELIMIT,
  		.procname	= "icmp_ratelimit",
  		.data		= &init_net.ipv4.sysctl_icmp_ratelimit,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_ms_jiffies,
  		.strategy	= sysctl_ms_jiffies
  	},
  	{
  		.ctl_name	= NET_IPV4_ICMP_RATEMASK,
  		.procname	= "icmp_ratemask",
  		.data		= &init_net.ipv4.sysctl_icmp_ratemask,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.ctl_name	= CTL_UNNUMBERED,
  		.procname	= "rt_cache_rebuild_count",
  		.data		= &init_net.ipv4.sysctl_rt_cache_rebuild_count,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{ }
  };
  
  struct ctl_path net_ipv4_ctl_path[] = {
  	{ .procname = "net", .ctl_name = CTL_NET, },
  	{ .procname = "ipv4", .ctl_name = NET_IPV4, },
  	{ },
  };
  EXPORT_SYMBOL_GPL(net_ipv4_ctl_path);
  
  static __net_init int ipv4_sysctl_init_net(struct net *net)
  {
  	struct ctl_table *table;
  
  	table = ipv4_net_table;
  	if (net != &init_net) {
  		table = kmemdup(table, sizeof(ipv4_net_table), GFP_KERNEL);
  		if (table == NULL)
  			goto err_alloc;
  
  		table[0].data =
  			&net->ipv4.sysctl_icmp_echo_ignore_all;
  		table[1].data =
  			&net->ipv4.sysctl_icmp_echo_ignore_broadcasts;
  		table[2].data =
  			&net->ipv4.sysctl_icmp_ignore_bogus_error_responses;
  		table[3].data =
  			&net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr;
  		table[4].data =
  			&net->ipv4.sysctl_icmp_ratelimit;
  		table[5].data =
  			&net->ipv4.sysctl_icmp_ratemask;
  		table[6].data =
  			&net->ipv4.sysctl_rt_cache_rebuild_count;
  	}
  
  	net->ipv4.sysctl_rt_cache_rebuild_count = 4;
  
  	net->ipv4.ipv4_hdr = register_net_sysctl_table(net,
  			net_ipv4_ctl_path, table);
  	if (net->ipv4.ipv4_hdr == NULL)
  		goto err_reg;
  
  	return 0;
  
  err_reg:
  	if (net != &init_net)
  		kfree(table);
  err_alloc:
  	return -ENOMEM;
  }
  
  static __net_exit void ipv4_sysctl_exit_net(struct net *net)
  {
  	struct ctl_table *table;
  
  	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_sysctl_paths(net_ipv4_ctl_path, ipv4_table);
  	if (hdr == NULL)
  		return -ENOMEM;
  
  	if (register_pernet_subsys(&ipv4_sysctl_ops)) {
  		unregister_sysctl_table(hdr);
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  __initcall(sysctl_ipv4_init);
  