net: tcp: Define the TCP_MAX_WSCALE instead of literal number 14

Define one new macro TCP_MAX_WSCALE instead of literal number '14',
and use U16_MAX instead of 65535 as the max value of TCP window.
There is another minor change, use rounddown(space, mss) instead of
(space / mss) * mss;

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gao Feng 2017-04-04 21:09:48 +08:00 committed by David S. Miller
parent 5e35141066
commit 589c49cbf9
4 changed files with 14 additions and 12 deletions

View File

@ -78,6 +78,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
/* Maximal number of ACKs sent quickly to accelerate slow-start. */
#define TCP_MAX_QUICKACKS 16U
/* Maximal number of window scale according to RFC1323 */
#define TCP_MAX_WSCALE 14U
/* urg_data states */
#define TCP_URG_VALID 0x0100
#define TCP_URG_NOTYET 0x0200

View File

@ -2393,7 +2393,7 @@ static int tcp_repair_options_est(struct tcp_sock *tp,
u16 snd_wscale = opt.opt_val & 0xFFFF;
u16 rcv_wscale = opt.opt_val >> 16;
if (snd_wscale > 14 || rcv_wscale > 14)
if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE)
return -EFBIG;
tp->rx_opt.snd_wscale = snd_wscale;

View File

@ -3759,11 +3759,12 @@ void tcp_parse_options(const struct sk_buff *skb,
!estab && sysctl_tcp_window_scaling) {
__u8 snd_wscale = *(__u8 *)ptr;
opt_rx->wscale_ok = 1;
if (snd_wscale > 14) {
net_info_ratelimited("%s: Illegal window scaling value %d >14 received\n",
if (snd_wscale > TCP_MAX_WSCALE) {
net_info_ratelimited("%s: Illegal window scaling value %d > %u received\n",
__func__,
snd_wscale);
snd_wscale = 14;
snd_wscale,
TCP_MAX_WSCALE);
snd_wscale = TCP_MAX_WSCALE;
}
opt_rx->snd_wscale = snd_wscale;
}

View File

@ -212,12 +212,12 @@ void tcp_select_initial_window(int __space, __u32 mss,
/* If no clamp set the clamp to the max possible scaled window */
if (*window_clamp == 0)
(*window_clamp) = (65535 << 14);
(*window_clamp) = (U16_MAX << TCP_MAX_WSCALE);
space = min(*window_clamp, space);
/* Quantize space offering to a multiple of mss if possible. */
if (space > mss)
space = (space / mss) * mss;
space = rounddown(space, mss);
/* NOTE: offering an initial window larger than 32767
* will break some buggy TCP stacks. If the admin tells us
@ -234,13 +234,11 @@ void tcp_select_initial_window(int __space, __u32 mss,
(*rcv_wscale) = 0;
if (wscale_ok) {
/* Set window scaling on max possible window
* See RFC1323 for an explanation of the limit to 14
*/
/* Set window scaling on max possible window */
space = max_t(u32, space, sysctl_tcp_rmem[2]);
space = max_t(u32, space, sysctl_rmem_max);
space = min_t(u32, space, *window_clamp);
while (space > 65535 && (*rcv_wscale) < 14) {
while (space > U16_MAX && (*rcv_wscale) < TCP_MAX_WSCALE) {
space >>= 1;
(*rcv_wscale)++;
}
@ -253,7 +251,7 @@ void tcp_select_initial_window(int __space, __u32 mss,
}
/* Set the clamp no higher than max representable value */
(*window_clamp) = min(65535U << (*rcv_wscale), *window_clamp);
(*window_clamp) = min_t(__u32, U16_MAX << (*rcv_wscale), *window_clamp);
}
EXPORT_SYMBOL(tcp_select_initial_window);