Make default TCP default congestion control to a per namespace
value. The congestion control setting of new namespaces is inherited
from the root namespace. Modules are only autoloaded in the root namespace.
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
include/net/netns/ipv4.h | 1 +
include/net/tcp.h | 6 ++--
net/ipv4/fib_semantics.c | 4 +--
net/ipv4/sysctl_net_ipv4.c | 19 ++++++-----
net/ipv4/tcp_cong.c | 78 ++++++++++++++++++++++------------------------
net/ipv4/tcp_ipv4.c | 9 ++++++
net/ipv6/route.c | 3 +-
7 files changed, 65 insertions(+), 55 deletions(-)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 379550f8124a..23ddfcfc8afe 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -155,6 +155,7 @@ struct netns_ipv4 {
int sysctl_tcp_invalid_ratelimit;
int sysctl_tcp_pacing_ss_ratio;
int sysctl_tcp_pacing_ca_ratio;
+ const struct tcp_congestion_ops __rcu *tcp_congestion_control;
struct inet_timewait_death_row tcp_death_row;
int sysctl_max_syn_backlog;
int sysctl_tcp_fastopen;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index babfd4da1515..64d4099d41da 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1005,8 +1005,8 @@ void tcp_unregister_congestion_control(struct
tcp_congestion_ops *type);
void tcp_assign_congestion_control(struct sock *sk);
void tcp_init_congestion_control(struct sock *sk);
void tcp_cleanup_congestion_control(struct sock *sk);
-int tcp_set_default_congestion_control(const char *name);
-void tcp_get_default_congestion_control(char *name);
+int tcp_set_default_congestion_control(struct net *net, const char *name);
+void tcp_get_default_congestion_control(struct net *net, char *name);
void tcp_get_available_congestion_control(char *buf, size_t len);
void tcp_get_allowed_congestion_control(char *buf, size_t len);
int tcp_set_allowed_congestion_control(char *allowed);
@@ -1020,7 +1020,7 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32
acked);
extern struct tcp_congestion_ops tcp_reno;
struct tcp_congestion_ops *tcp_ca_find_key(u32 key);
-u32 tcp_ca_get_key_by_name(const char *name, bool *ecn_ca);
+u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca);
#ifdef CONFIG_INET
char *tcp_ca_get_name_by_key(u32 key, char *buffer);
#else
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 589caaa90613..f04d944f8abe 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -710,7 +710,7 @@ bool fib_metrics_match(struct fib_config *cfg, struct
fib_info *fi)
bool ecn_ca = false;
nla_strlcpy(tmp, nla, sizeof(tmp));
- val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
+ val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
} else {
val = nla_get_u32(nla);
}
@@ -1030,7 +1030,7 @@ fib_convert_metrics(struct fib_info *fi, const struct
fib_config *cfg)
char tmp[TCP_CA_NAME_MAX];
nla_strlcpy(tmp, nla, sizeof(tmp));
- val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
+ val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
if (val == TCP_CA_UNSPEC)
return -EINVAL;
} else {
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index a82b44038308..c97d9e614017 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -201,6 +201,8 @@ static int ipv4_ping_group_range(struct ctl_table *table,
int write,
static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
+ struct net *net = container_of(ctl->data, struct net,
+ ipv4.tcp_congestion_control);
char val[TCP_CA_NAME_MAX];
struct ctl_table tbl = {
.data = val,
@@ -208,11 +210,11 @@ static int proc_tcp_congestion_control(struct ctl_table
*ctl, int write,
};
int ret;
- tcp_get_default_congestion_control(val);
+ tcp_get_default_congestion_control(net, val);
ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0)
- ret = tcp_set_default_congestion_control(val);
+ ret = tcp_set_default_congestion_control(net, val);
return ret;
}
@@ -463,12 +465,6 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
- {
- .procname = "tcp_congestion_control",
- .mode = 0644,
- .maxlen = TCP_CA_NAME_MAX,
- .proc_handler = proc_tcp_congestion_control,
- },
#ifdef CONFIG_NETLABEL
{
.procname = "cipso_cache_enable",
@@ -780,6 +776,13 @@ static struct ctl_table ipv4_net_table[] = {
},
#endif
{
+ .procname = "tcp_congestion_control",
+ .data = &init_net.ipv4.tcp_congestion_control,
+ .mode = 0644,
+ .maxlen = TCP_CA_NAME_MAX,
+ .proc_handler = proc_tcp_congestion_control,
+ },
+ {
.procname = "tcp_keepalive_time",
.data = &init_net.ipv4.sysctl_tcp_keepalive_time,
.maxlen = sizeof(int),
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 2f26124fd160..8c54cf1083a6 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -33,11 +33,13 @@ static struct tcp_congestion_ops *tcp_ca_find(const char
*name)
}
/* Must be called with rcu lock held */
-static const struct tcp_congestion_ops *__tcp_ca_find_autoload(const char
*name)
+static struct tcp_congestion_ops *tcp_ca_find_autoload(struct net *net,
+ const char *name)
{
- const struct tcp_congestion_ops *ca = tcp_ca_find(name);
+ struct tcp_congestion_ops *ca = tcp_ca_find(name);
+
#ifdef CONFIG_MODULES
- if (!ca && capable(CAP_NET_ADMIN)) {
+ if (!ca && net == &init_net && capable(CAP_NET_ADMIN)) {
rcu_read_unlock();
request_module("tcp_%s", name);
rcu_read_lock();
@@ -115,7 +117,7 @@ void tcp_unregister_congestion_control(struct
tcp_congestion_ops *ca)
}
EXPORT_SYMBOL_GPL(tcp_unregister_congestion_control);
-u32 tcp_ca_get_key_by_name(const char *name, bool *ecn_ca)
+u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca)
{
const struct tcp_congestion_ops *ca;
u32 key = TCP_CA_UNSPEC;
@@ -123,7 +125,7 @@ u32 tcp_ca_get_key_by_name(const char *name, bool *ecn_ca)
might_sleep();
rcu_read_lock();
- ca = __tcp_ca_find_autoload(name);
+ ca = tcp_ca_find_autoload(net, name);
if (ca) {
key = ca->key;
*ecn_ca = ca->flags & TCP_CONG_NEEDS_ECN;
@@ -153,23 +155,18 @@ EXPORT_SYMBOL_GPL(tcp_ca_get_name_by_key);
/* Assign choice of congestion control. */
void tcp_assign_congestion_control(struct sock *sk)
{
+ struct net *net = sock_net(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
- struct tcp_congestion_ops *ca;
+ const struct tcp_congestion_ops *ca;
rcu_read_lock();
- list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
- if (likely(try_module_get(ca->owner))) {
- icsk->icsk_ca_ops = ca;
- goto out;
- }
- /* Fallback to next available. The last really
- * guaranteed fallback is Reno from this list.
- */
- }
-out:
+ ca = rcu_dereference(net->ipv4.tcp_congestion_control);
+ if (unlikely(!try_module_get(ca->owner)))
+ ca = &tcp_reno;
+ icsk->icsk_ca_ops = ca;
rcu_read_unlock();
- memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
+ memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
if (ca->flags & TCP_CONG_NEEDS_ECN)
INET_ECN_xmit(sk);
else
@@ -214,29 +211,27 @@ void tcp_cleanup_congestion_control(struct sock *sk)
}
/* Used by sysctl to change default congestion control */
-int tcp_set_default_congestion_control(const char *name)
+int tcp_set_default_congestion_control(struct net *net, const char *name)
{
struct tcp_congestion_ops *ca;
- int ret = -ENOENT;
+ const struct tcp_congestion_ops *prev;
+ int ret;
- spin_lock(&tcp_cong_list_lock);
- ca = tcp_ca_find(name);
-#ifdef CONFIG_MODULES
- if (!ca && capable(CAP_NET_ADMIN)) {
- spin_unlock(&tcp_cong_list_lock);
-
- request_module("tcp_%s", name);
- spin_lock(&tcp_cong_list_lock);
- ca = tcp_ca_find(name);
- }
-#endif
+ rcu_read_lock();
+ ca = tcp_ca_find_autoload(net, name);
+ if (!ca) {
+ ret = -ENOENT;
+ } else if (!try_module_get(ca->owner)) {
+ ret = -EBUSY;
+ } else {
+ prev = xchg(&net->ipv4.tcp_congestion_control, ca);
+ if (prev)
+ module_put(prev->owner);
- if (ca) {
- ca->flags |= TCP_CONG_NON_RESTRICTED; /* default is always
allowed */
- list_move(&ca->list, &tcp_cong_list);
+ ca->flags |= TCP_CONG_NON_RESTRICTED;
ret = 0;
}
- spin_unlock(&tcp_cong_list_lock);
+ rcu_read_unlock();
return ret;
}
@@ -244,7 +239,8 @@ int tcp_set_default_congestion_control(const char *name)
/* Set default value from kernel configuration at bootup */
static int __init tcp_congestion_default(void)
{
- return tcp_set_default_congestion_control(CONFIG_DEFAULT_TCP_CONG);
+ return tcp_set_default_congestion_control(&init_net,
+ CONFIG_DEFAULT_TCP_CONG);
}
late_initcall(tcp_congestion_default);
@@ -264,14 +260,12 @@ void tcp_get_available_congestion_control(char *buf,
size_t maxlen)
}
/* Get current default congestion control */
-void tcp_get_default_congestion_control(char *name)
+void tcp_get_default_congestion_control(struct net *net, char *name)
{
- struct tcp_congestion_ops *ca;
- /* We will always have reno... */
- BUG_ON(list_empty(&tcp_cong_list));
+ const struct tcp_congestion_ops *ca;
rcu_read_lock();
- ca = list_entry(tcp_cong_list.next, struct tcp_congestion_ops, list);
+ ca = rcu_dereference(net->ipv4.tcp_congestion_control);
strncpy(name, ca->name, TCP_CA_NAME_MAX);
rcu_read_unlock();
}
@@ -351,12 +345,14 @@ int tcp_set_congestion_control(struct sock *sk, const
char *name, bool load, boo
if (!load)
ca = tcp_ca_find(name);
else
- ca = __tcp_ca_find_autoload(name);
+ ca = tcp_ca_find_autoload(sock_net(sk), name);
+
/* No change asking for existing value */
if (ca == icsk->icsk_ca_ops) {
icsk->icsk_ca_setsockopt = 1;
goto out;
}
+
if (!ca) {
err = -ENOENT;
} else if (!load) {
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0162c577bb9c..d5361c0d007c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2430,6 +2430,8 @@ static void __net_exit tcp_sk_exit(struct net *net)
{
int cpu;
+ module_put(net->ipv4.tcp_congestion_control->owner);
+
for_each_possible_cpu(cpu)
inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
free_percpu(net->ipv4.tcp_sk);
@@ -2515,6 +2517,13 @@ static int __net_init tcp_sk_init(struct net *net)
net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
atomic_set(&net->ipv4.tfo_active_disable_times, 0);
+ /* Reno is always built in */
+ if (!net_eq(net, &init_net) &&
+ try_module_get(init_net.ipv4.tcp_congestion_control->owner))
+ net->ipv4.tcp_congestion_control =
init_net.ipv4.tcp_congestion_control;
+ else
+ net->ipv4.tcp_congestion_control = &tcp_reno;
+
return 0;
fail:
tcp_sk_exit(net);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 70d9659fc1e9..05eb7bc36156 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2378,6 +2378,7 @@ static int ip6_dst_gc(struct dst_ops *ops)
static int ip6_convert_metrics(struct mx6_config *mxc,
const struct fib6_config *cfg)
{
+ struct net *net = cfg->fc_nlinfo.nl_net;
bool ecn_ca = false;
struct nlattr *nla;
int remaining;
@@ -2403,7 +2404,7 @@ static int ip6_convert_metrics(struct mx6_config *mxc,
char tmp[TCP_CA_NAME_MAX];
nla_strlcpy(tmp, nla, sizeof(tmp));
- val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
+ val = tcp_ca_get_key_by_name(net, tmp, &ecn_ca);
if (val == TCP_CA_UNSPEC)
goto err;
} else {
--
2.11.0
