-#define SOCKNAL_TX_LOW_WATER(sk) (((sk)->sk_sndbuf*8)/10)
-
-#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,72))
-# define sk_allocation allocation
-# define sk_data_ready data_ready
-# define sk_write_space write_space
-# define sk_user_data user_data
-# define sk_prot prot
-# define sk_sndbuf sndbuf
-# define sk_socket socket
+#include <linux/crc32.h>
+static inline __u32 ksocknal_csum(__u32 crc, unsigned char const *p, size_t len)
+{
+#if 1
+ return crc32_le(crc, p, len);
+#else
+ while (len-- > 0)
+ crc = ((crc + 0x100) & ~0xff) | ((crc + *p++) & 0xff) ;
+ return crc;