[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: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index fd3c0c0..db42808 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -351,10 +351,16 @@ tcp_frto - BOOLEAN
        where packet loss is typically due to random radio interference
        rather than intermediate router congestion.
 
        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.
 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.
 
 somaxconn - INTEGER
        Limit of socket listen() backlog, known in userspace as SOMAXCONN.

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index d98562f..28a4827 100644 (file)
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -426,6 +426,7 @@ enum
        NET_CIPSOV4_CACHE_BUCKET_SIZE=119,
        NET_CIPSOV4_RBM_OPTFMT=120,
        NET_CIPSOV4_RBM_STRICTVALID=121,
        NET_CIPSOV4_CACHE_BUCKET_SIZE=119,
        NET_CIPSOV4_RBM_OPTFMT=120,
        NET_CIPSOV4_RBM_STRICTVALID=121,

+       NET_TCP_AVAIL_CONG_CONTROL=122,

 };
 
 enum {
 };
 
 enum {

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 246916c..6af4baf 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -620,6 +620,9 @@ enum tcp_ca_event {
  * Interface for adding new TCP congestion control handlers
  */
 #define TCP_CA_NAME_MAX        16
  * 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;
 
 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_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);
 
 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
 extern void tcp_slow_start(struct tcp_sock *tp);
 

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 15061b3..2e770f4 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -129,6 +129,23 @@ static int sysctl_tcp_congestion_control(ctl_table *table, int __user *name,
        return ret;
 }
 
        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,
 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 */
                .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 }
 };
 
        { .ctl_name = 0 }
 };
 

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 1e2982f..d846d7b 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -139,6 +139,22 @@ static int __init tcp_congestion_default(void)
 late_initcall(tcp_congestion_default);
 
 
 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)
 {
 /* Get current default congestion control */
 void tcp_get_default_congestion_control(char *name)
 {