[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: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f3dbc8d..882436d 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1927,6 +1927,25 @@
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 @@
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 @@
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)
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 665394a..4970d10 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -21,7 +21,7 @@
{
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 @@
{
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 @@
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 @@
.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);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 9122814..ebf1123 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2048,7 +2048,7 @@
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;