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Commit 5f8ef48d authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
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[TCP]: Allow choosing TCP congestion control via sockopt. 



Allow using setsockopt to set TCP congestion control to use on a per
socket basis.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 51b0bded

include/linux/tcp.h

+1 −0
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ enum { 
#define TCP_WINDOW_CLAMP	10	/* Bound advertised window */

#define TCP_INFO		11	/* Information about this connection. */

#define TCP_QUICKACK		12	/* Block/reenable quick acks */

#define TCP_CONGESTION		13	/* Congestion control algorithm */



#define TCPI_OPT_TIMESTAMPS	1

#define TCPI_OPT_SACK		2

include/net/tcp.h

+2 −1
Original line number Diff line number Diff line
@@ -1162,8 +1162,9 @@ extern void tcp_init_congestion_control(struct tcp_sock *tp); 
extern void tcp_cleanup_congestion_control(struct tcp_sock *tp);

extern int tcp_set_default_congestion_control(const char *name);

extern void tcp_get_default_congestion_control(char *name);

extern int tcp_set_congestion_control(struct tcp_sock *tp, const char *name);



extern struct tcp_congestion_ops tcp_reno;

extern struct tcp_congestion_ops tcp_init_congestion_ops;

extern u32 tcp_reno_ssthresh(struct tcp_sock *tp);

extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack,

				u32 rtt, u32 in_flight, int flag);

net/ipv4/tcp.c

+30 −1
Original line number Diff line number Diff line
@@ -1927,6 +1927,25 @@ int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 
		return tp->af_specific->setsockopt(sk, level, optname,

						   optval, optlen);



	/* This is a string value all the others are int's */

	if (optname == TCP_CONGESTION) {

		char name[TCP_CA_NAME_MAX];



		if (optlen < 1)

			return -EINVAL;



		val = strncpy_from_user(name, optval,

					min(TCP_CA_NAME_MAX-1, optlen));

		if (val < 0)

			return -EFAULT;

		name[val] = 0;



		lock_sock(sk);

		err = tcp_set_congestion_control(tp, name);

		release_sock(sk);

		return err;

	}



	if (optlen < sizeof(int))

		return -EINVAL;
@@ -2211,6 +2230,16 @@ int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 
	case TCP_QUICKACK:

		val = !tp->ack.pingpong;

		break;



	case TCP_CONGESTION:

		if (get_user(len, optlen))

			return -EFAULT;

		len = min_t(unsigned int, len, TCP_CA_NAME_MAX);

		if (put_user(len, optlen))

			return -EFAULT;

		if (copy_to_user(optval, tp->ca_ops->name, len))

			return -EFAULT;

		return 0;

	default:

		return -ENOPROTOOPT;

	};
@@ -2224,7 +2253,7 @@ int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 




extern void __skb_cb_too_small_for_tcp(int, int);

extern void tcpdiag_init(void);

extern struct tcp_congestion_ops tcp_reno;



static __initdata unsigned long thash_entries;

static int __init set_thash_entries(char *str)

net/ipv4/tcp_cong.c

+44 −2
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ static struct tcp_congestion_ops *tcp_ca_find(const char *name) 
{

	struct tcp_congestion_ops *e;



	list_for_each_entry(e, &tcp_cong_list, list) {

	list_for_each_entry_rcu(e, &tcp_cong_list, list) {

		if (strcmp(e->name, name) == 0)

			return e;

	}
@@ -77,6 +77,9 @@ void tcp_init_congestion_control(struct tcp_sock *tp) 
{

	struct tcp_congestion_ops *ca;



	if (tp->ca_ops != &tcp_init_congestion_ops)

		return;



	rcu_read_lock();

	list_for_each_entry_rcu(ca, &tcp_cong_list, list) {

		if (try_module_get(ca->owner)) {
@@ -139,6 +142,34 @@ void tcp_get_default_congestion_control(char *name) 
	rcu_read_unlock();

}



/* Change congestion control for socket */

int tcp_set_congestion_control(struct tcp_sock *tp, const char *name)

{

	struct tcp_congestion_ops *ca;

	int err = 0;



	rcu_read_lock();

	ca = tcp_ca_find(name);

	if (ca == tp->ca_ops)

		goto out;



	if (!ca)

		err = -ENOENT;



	else if (!try_module_get(ca->owner))

		err = -EBUSY;



	else {

		tcp_cleanup_congestion_control(tp);

		tp->ca_ops = ca;

		if (tp->ca_ops->init)

			tp->ca_ops->init(tp);

	}

 out:

	rcu_read_unlock();

	return err;

}



/*

 * TCP Reno congestion control

 * This is special case used for fallback as well.
@@ -192,4 +223,15 @@ struct tcp_congestion_ops tcp_reno = { 
	.min_cwnd	= tcp_reno_min_cwnd,

};



EXPORT_SYMBOL_GPL(tcp_reno);
 
/* Initial congestion control used (until SYN)

 * really reno under another name so we can tell difference

 * during tcp_set_default_congestion_control

 */

struct tcp_congestion_ops tcp_init_congestion_ops  = {

	.name		= "",

	.owner		= THIS_MODULE,

	.ssthresh	= tcp_reno_ssthresh,

	.cong_avoid	= tcp_reno_cong_avoid,

	.min_cwnd	= tcp_reno_min_cwnd,

};

EXPORT_SYMBOL_GPL(tcp_init_congestion_ops);

net/ipv4/tcp_ipv4.c

+1 −1
Original line number Diff line number Diff line
@@ -2048,7 +2048,7 @@ static int tcp_v4_init_sock(struct sock *sk) 
	tp->mss_cache_std = tp->mss_cache = 536;



	tp->reordering = sysctl_tcp_reordering;

	tp->ca_ops = &tcp_reno;

	tp->ca_ops = &tcp_init_congestion_ops;



	sk->sk_state = TCP_CLOSE;