[TCP]: Add pluggable congestion control algorithm infrastructure.

Allow TCP to have multiple pluggable congestion control algorithms.
Algorithms are defined by a set of operations and can be built in
or modules.  The legacy "new RENO" algorithm is used as a starting
point and fallback.

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

1 files changed, 45 insertions, 69 deletions

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 23068bddbf0b..e32894532416 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -118,6 +118,45 @@ static int ipv4_sysctl_forward_strategy(ctl_table *table,
         return 1;
 }
 
+static int proc_tcp_congestion_control(ctl_table *ctl, int write, struct file * filp,
+                                       void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        char val[TCP_CA_NAME_MAX];
+        ctl_table tbl = {
+                .data = val,
+                .maxlen = TCP_CA_NAME_MAX,
+        };
+        int ret;
+
+        tcp_get_default_congestion_control(val);
+
+        ret = proc_dostring(&tbl, write, filp, buffer, lenp, ppos);
+        if (write && ret == 0)
+                ret = tcp_set_default_congestion_control(val);
+        return ret;
+}
+
+int sysctl_tcp_congestion_control(ctl_table *table, int __user *name, int nlen,
+                                  void __user *oldval, size_t __user *oldlenp,
+                                  void __user *newval, size_t newlen,
+                                  void **context)
+{
+        char val[TCP_CA_NAME_MAX];
+        ctl_table tbl = {
+                .data = val,
+                .maxlen = TCP_CA_NAME_MAX,
+        };
+        int ret;
+
+        tcp_get_default_congestion_control(val);
+        ret = sysctl_string(&tbl, name, nlen, oldval, oldlenp, newval, newlen,
+                            context);
+        if (ret == 0 && newval && newlen)
+                ret = tcp_set_default_congestion_control(val);
+        return ret;
+}
+
+
 ctl_table ipv4_table[] = {
         {
                 .ctl_name       = NET_IPV4_TCP_TIMESTAMPS,
@@ -612,70 +651,6 @@ ctl_table ipv4_table[] = {
                 .proc_handler   = &proc_dointvec,
         },
         {
-                .ctl_name       = NET_TCP_WESTWOOD, 
-                .procname       = "tcp_westwood",
-                .data           = &sysctl_tcp_westwood,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_VEGAS,
-                .procname       = "tcp_vegas_cong_avoid",
-                .data           = &sysctl_tcp_vegas_cong_avoid,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_VEGAS_ALPHA,
-                .procname       = "tcp_vegas_alpha",
-                .data           = &sysctl_tcp_vegas_alpha,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_VEGAS_BETA,
-                .procname       = "tcp_vegas_beta",
-                .data           = &sysctl_tcp_vegas_beta,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_VEGAS_GAMMA,
-                .procname       = "tcp_vegas_gamma",
-                .data           = &sysctl_tcp_vegas_gamma,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_BIC,
-                .procname       = "tcp_bic",
-                .data           = &sysctl_tcp_bic,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_BIC_FAST_CONVERGENCE,
-                .procname       = "tcp_bic_fast_convergence",
-                .data           = &sysctl_tcp_bic_fast_convergence,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
-                .ctl_name       = NET_TCP_BIC_LOW_WINDOW,
-                .procname       = "tcp_bic_low_window",
-                .data           = &sysctl_tcp_bic_low_window,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
-        },
-        {
                 .ctl_name       = NET_TCP_MODERATE_RCVBUF,
                 .procname       = "tcp_moderate_rcvbuf",
                 .data           = &sysctl_tcp_moderate_rcvbuf,
@@ -692,13 +667,14 @@ ctl_table ipv4_table[] = {
                 .proc_handler   = &proc_dointvec,
         },
         {
-                .ctl_name       = NET_TCP_BIC_BETA,
-                .procname       = "tcp_bic_beta",
-                .data           = &sysctl_tcp_bic_beta,
-                .maxlen         = sizeof(int),
+                .ctl_name       = NET_TCP_CONG_CONTROL,
+                .procname       = "tcp_congestion_control",
                 .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
+                .maxlen         = TCP_CA_NAME_MAX,
+                .proc_handler   = &proc_tcp_congestion_control,
+                .strategy       = &sysctl_tcp_congestion_control,
         },
+
         { .ctl_name = 0 }
 };