[NET]: Replace CONFIG_NET_DEBUG with sysctl.

Covert network warning messages from a compile time to runtime choice.
Removes kernel config option and replaces it with new /proc/sys/net/core/warnings.

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

6 files changed, 25 insertions, 14 deletions

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 5484ab5efd4f..7aaf09b86a55 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1421,6 +1421,15 @@ fewer messages that will be written. Message_burst controls when messages will
 be dropped.  The  default  settings  limit  warning messages to one every five
 seconds.
 
+warnings
+--------
+
+This controls console messages from the networking stack that can occur because
+of problems on the network like duplicate address or bad checksums. Normally,
+this should be enabled, but if the problem persists the messages can be
+disabled.
+
+
 netdev_max_backlog
 ------------------
 
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index c9ccb550206f..df2d9ed20a4e 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -290,6 +290,7 @@ enum
         NET_CORE_BUDGET=19,
         NET_CORE_AEVENT_ETIME=20,
         NET_CORE_AEVENT_RSEQTH=21,
+        NET_CORE_WARNINGS=22,
 };
 
 /* /proc/sys/net/ethernet */
diff --git a/include/net/sock.h b/include/net/sock.h
index d093e49fdc85..51246579592e 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1334,14 +1334,12 @@ extern int sock_get_timestampns(struct sock *, struct timespec __user *);
 /* 
  *      Enable debug/info messages 
  */
+extern int net_msg_warn;
+#define NETDEBUG(fmt, args...) \
+        do { if (net_msg_warn) printk(fmt,##args); } while (0)
 
-#ifdef CONFIG_NETDEBUG
-#define NETDEBUG(fmt, args...)  printk(fmt,##args)
-#define LIMIT_NETDEBUG(fmt, args...) do { if (net_ratelimit()) printk(fmt,##args); } while(0)
-#else
-#define NETDEBUG(fmt, args...)  do { } while (0)
-#define LIMIT_NETDEBUG(fmt, args...) do { } while(0)
-#endif
+#define LIMIT_NETDEBUG(fmt, args...) \
+        do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)
 
 /*
  * Macros for sleeping on a socket. Use them like this:
diff --git a/net/Kconfig b/net/Kconfig
index 915657832d94..e2d9b3b9cda4 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -27,13 +27,6 @@ if NET
 
 menu "Networking options"
 
-config NETDEBUG
-        bool "Network packet debugging"
-        help
-          You can say Y here if you want to get additional messages useful in
-          debugging bad packets, but can overwhelm logs under denial of service
-          attacks.
-
 source "net/packet/Kconfig"
 source "net/unix/Kconfig"
 source "net/xfrm/Kconfig"
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 1e75b1585460..b29712033dd4 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -136,6 +136,14 @@ ctl_table core_table[] = {
                 .mode           = 0644,
                 .proc_handler   = &proc_dointvec
         },
+        {
+                .ctl_name       = NET_CORE_WARNINGS,
+                .procname       = "warnings",
+                .data           = &net_msg_warn,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec
+        },
         { .ctl_name = 0 }
 };
 
diff --git a/net/core/utils.c b/net/core/utils.c
index 07236c17fab9..34f08107b98e 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -32,6 +32,8 @@
 
 int net_msg_cost = 5*HZ;
 int net_msg_burst = 10;
+int net_msg_warn = 1;
+EXPORT_SYMBOL(net_msg_warn);
 
 /*
  * All net warning printk()s should be guarded by this function.