diff options
Diffstat (limited to 'include/net/tcp.h')
| -rw-r--r-- | include/net/tcp.h | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index bb253b9b2f0..87d87740818 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -480,20 +480,21 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, struct ip_options *opt); #ifdef CONFIG_SYN_COOKIES -/* Syncookies use a monotonic timer which increments every 64 seconds. +/* Syncookies use a monotonic timer which increments every 60 seconds. * This counter is used both as a hash input and partially encoded into * the cookie value. A cookie is only validated further if the delta * between the current counter value and the encoded one is less than this, - * i.e. a sent cookie is valid only at most for 128 seconds (or less if + * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if * the counter advances immediately after a cookie is generated). */ #define MAX_SYNCOOKIE_AGE 2 static inline u32 tcp_cookie_time(void) { - struct timespec now; - getnstimeofday(&now); - return now.tv_sec >> 6; /* 64 seconds granularity */ + u64 val = get_jiffies_64(); + + do_div(val, 60 * HZ); + return val; } u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, |