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Commit 3ff825b2 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

[TCP]: Add tcp_available_congestion_control sysctl. 



Create /proc/sys/net/ipv4/tcp_available_congestion_control
that reflects currently available TCP choices.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b68dbcab

Documentation/networking/ip-sysctl.txt

+6 −0
Original line number Diff line number Diff line
@@ -351,10 +351,16 @@ tcp_frto - BOOLEAN 
	where packet loss is typically due to random radio interference

	rather than intermediate router congestion.



tcp_available_congestion_control - STRING

	Shows the available congestion control choices that are registered.

	More congestion control algorithms may be available as modules,

	but not loaded.



tcp_congestion_control - STRING

	Set the congestion control algorithm to be used for new

	connections. The algorithm "reno" is always available, but

	additional choices may be available based on kernel configuration.

	Default is set as part of kernel configuration.



somaxconn - INTEGER

	Limit of socket listen() backlog, known in userspace as SOMAXCONN.

include/linux/sysctl.h

+1 −0
Original line number Diff line number Diff line
@@ -426,6 +426,7 @@ enum 
	NET_CIPSOV4_CACHE_BUCKET_SIZE=119,

	NET_CIPSOV4_RBM_OPTFMT=120,

	NET_CIPSOV4_RBM_STRICTVALID=121,

	NET_TCP_AVAIL_CONG_CONTROL=122,

};



enum {

include/net/tcp.h

+4 −0
Original line number Diff line number Diff line
@@ -620,6 +620,9 @@ enum tcp_ca_event { 
 * Interface for adding new TCP congestion control handlers

 */

#define TCP_CA_NAME_MAX	16

#define TCP_CA_MAX	128

#define TCP_CA_BUF_MAX	(TCP_CA_NAME_MAX*TCP_CA_MAX)



struct tcp_congestion_ops {

	struct list_head	list;
@@ -659,6 +662,7 @@ extern void tcp_init_congestion_control(struct sock *sk); 
extern void tcp_cleanup_congestion_control(struct sock *sk);

extern int tcp_set_default_congestion_control(const char *name);

extern void tcp_get_default_congestion_control(char *name);

extern void tcp_get_available_congestion_control(char *buf, size_t len);

extern int tcp_set_congestion_control(struct sock *sk, const char *name);

extern void tcp_slow_start(struct tcp_sock *tp);

net/ipv4/sysctl_net_ipv4.c

+24 −0
Original line number Diff line number Diff line
@@ -129,6 +129,23 @@ static int sysctl_tcp_congestion_control(ctl_table *table, int __user *name, 
	return ret;

}



static int proc_tcp_available_congestion_control(ctl_table *ctl,

						 int write, struct file * filp,

						 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, filp, buffer, lenp, ppos);

	kfree(tbl.data);

	return ret;

}



ctl_table ipv4_table[] = {

        {

		.ctl_name	= NET_IPV4_TCP_TIMESTAMPS,
@@ -731,6 +748,13 @@ ctl_table ipv4_table[] = { 
		.proc_handler	= &proc_dointvec,

	},

#endif /* CONFIG_NETLABEL */

	{

		.ctl_name	= NET_TCP_AVAIL_CONG_CONTROL,

		.procname	= "tcp_available_congestion_control",

		.maxlen		= TCP_CA_BUF_MAX,

		.mode		= 0444,

		.proc_handler   = &proc_tcp_available_congestion_control,

	},

	{ .ctl_name = 0 }

};

net/ipv4/tcp_cong.c

+16 −0
Original line number Diff line number Diff line
@@ -139,6 +139,22 @@ static int __init tcp_congestion_default(void) 
late_initcall(tcp_congestion_default);





/* Build string with list of available congestion control values */

void tcp_get_available_congestion_control(char *buf, size_t maxlen)

{

	struct tcp_congestion_ops *ca;

	size_t offs = 0;



	rcu_read_lock();

	list_for_each_entry_rcu(ca, &tcp_cong_list, list) {

		offs += snprintf(buf + offs, maxlen - offs,

				 "%s%s",

				 offs == 0 ? "" : " ", ca->name);



	}

	rcu_read_unlock();

}



/* Get current default congestion control */

void tcp_get_default_congestion_control(char *name)

{