| Message ID | 4AC57AC5.3080703@gmail.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, 02 Oct 2009 00:00:05 -0400 William Allen Simpson <william.allen.simpson@gmail.com> wrote: > [My first post here, hopefully not a FAQ, as I've googled it, but cannot find > the definitive answer.] > > I've been trying to add a sysctl, and I've noticed this message: > > sysctl table check failed: /net/ipv4/tcp_cookie_size .3.5.126 Unknown sysctl binary path > > I modeled the code on sysctl_tcp_syncookies, and apparently I'm missing some > additional magic? Or does something need to be done other than C? The sysctl table check code is kernel/sysctl.c, it maps numerical sysctl values to /proc paths so that the permissions checks on the numeric sysctl match those of the /proc file involved. Hint: the easiest way to find things out is to use git grep to see how any related sysctl is implemented. BUT numbered sysctl values are deprecated and should no longer be added. The current way is to use CTL_UNNUMBERED instead, if you use CTL_UNNUMBERED then the table does not need to be changed.
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index e76d3b2..8c74bec 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -435,6 +435,7 @@ enum NET_TCP_ALLOWED_CONG_CONTROL=123, NET_TCP_MAX_SSTHRESH=124, NET_TCP_FRTO_RESPONSE=125, + NET_TCP_COOKIE_SIZE=126, }; enum { diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 4710d21..e6174c9 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -340,6 +340,16 @@ static struct ctl_table ipv4_table[] = { .proc_handler = proc_dointvec_jiffies, .strategy = sysctl_jiffies }, +#ifdef CONFIG_TCP_OPT_COOKIE_EXTENSION + { + .ctl_name = NET_TCP_COOKIE_SIZE, + .procname = "tcp_cookie_size", + .data = &sysctl_tcp_cookie_size, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec + }, +#endif #ifdef CONFIG_SYN_COOKIES { .ctl_name = NET_TCP_SYNCOOKIES, diff --git a/include/net/tcp.h b/include/net/tcp.h index 56b7602..a53b2a8 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -208,6 +214,7 @@ extern int sysctl_tcp_synack_retries; extern int sysctl_tcp_retries1; extern int sysctl_tcp_retries2; extern int sysctl_tcp_orphan_retries; +extern int sysctl_tcp_cookie_size; extern int sysctl_tcp_syncookies; extern int sysctl_tcp_retrans_collapse; extern int sysctl_tcp_stdurg; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 5200aab..afbdc30 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -59,6 +59,14 @@ int sysctl_tcp_base_mss __read_mostly = 512; /* By default, RFC2861 behavior. */ int sysctl_tcp_slow_start_after_idle __read_mostly = 1; +#ifdef CONFIG_SYSCTL +/* By default, let the user enable it. */ +int sysctl_tcp_cookie_size __read_mostly = 0; +#else +int sysctl_tcp_cookie_size __read_mostly = TCP_COOKIE_MAX; +#endif + + /* Account for new data that has been sent to the network. */ static void tcp_event_new_data_sent(struct sock *sk, struct sk_buff *skb) {