sysadmin/ipxe
1
0
Fork 0
mirror of https://github.com/ipxe/ipxe synced 2025-12-26 17:42:47 +03:00
Code Issues Packages Projects Releases Wiki Activity

[tcp] Add support for TCP window scaling

Browse Source 
The maximum unscaled TCP window (64kB) implies a maximum bandwidth of
around 300kB/s on a WAN link with an RTT of 200ms.  Add support for
the TCP window scaling option to remove this upper limit.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2012-06-29 14:30:18 +01:00
parent 76d9c1a001
commit ea61075c60
2 changed files with 58 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
src/include/ipxe/tcp.h
View File

@@ -54,6 +54,31 @@ struct tcp_mss_option {
/** Code for the TCP MSS option */
#define TCP_OPTION_MSS 2
/** TCP window scale option */
struct tcp_window_scale_option {
uint8_t kind;
uint8_t length;
uint8_t scale;
} __attribute__ (( packed ));
/** Padded TCP window scale option (used for sending) */
struct tcp_window_scale_padded_option {
uint8_t nop;
struct tcp_window_scale_option wsopt;
} __attribute (( packed ));
/** Code for the TCP window scale option */
#define TCP_OPTION_WS 3
/** Advertised TCP window scale
*
* Using a scale factor of 2**9 provides for a maximum window of 32MB,
* which is sufficient to allow Gigabit-speed transfers with a 200ms
* RTT. The minimum advertised window is 512 bytes, which is still
* less than a single packet.
*/
#define TCP_RX_WINDOW_SCALE 9
/** TCP timestamp option */
struct tcp_timestamp_option {
uint8_t kind;
@@ -75,7 +100,9 @@ struct tcp_timestamp_padded_option {
struct tcp_options {
/** MSS option, if present */
const struct tcp_mss_option *mssopt;
/** Timestampe option, if present */
/** Window scale option, if present */
const struct tcp_window_scale_option *wsopt;
/** Timestamp option, if present */
const struct tcp_timestamp_option *tsopt;
};
@@ -316,6 +343,7 @@ struct tcp_options {
( MAX_LL_NET_HEADER_LEN + \
sizeof ( struct tcp_header ) + \
sizeof ( struct tcp_mss_option ) + \
sizeof ( struct tcp_window_scale_padded_option ) + \
sizeof ( struct tcp_timestamp_padded_option ) )
/**