mirror of
https://passt.top/passt
synced 2024-09-28 18:15:49 +00:00
4aff6f9392
When available, we want to retrieve our socket peer's advertised window and forward that to the guest. That information has been available from the kernel via the TCP_INFO getsockopt() since kernel commit 8f7baad7f035. Currently our probing for this is a bit odd. The HAS_SND_WND define determines if our headers include the tcp_snd_wnd field, but that doesn't necessarily mean the running kernel supports it. Currently we start by assuming it's _not_ available, but mark it as available if we ever see a non-zero value in the field. This is a bit hit and miss in two ways: * Zero is perfectly possible window the peer could report, so we can get false negatives * We're reading TCP_INFO into a local variable, which might not be zero initialised, so if the kernel _doesn't_ write it it could have non-zero garbage, giving us false positives. We can use a more direct way of probing for this: getsockopt() reports the length of the information retreived. So, check whether that's long enough to include the field. This lets us probe the availability of the field once and for all during initialisation. That in turn allows ctx to become a const pointer to tcp_prepare_flags() which cascades through many other functions. We also move the flag for the probe result from the ctx structure to a global, to match peek_offset_cap. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
17 lines
531 B
C
17 lines
531 B
C
/* SPDX-License-Identifier: GPL-2.0-or-later
|
|
* Copyright (c) 2021 Red Hat GmbH
|
|
* Author: Stefano Brivio <sbrivio@redhat.com>
|
|
*/
|
|
|
|
#ifndef TCP_BUF_H
|
|
#define TCP_BUF_H
|
|
|
|
void tcp_sock4_iov_init(const struct ctx *c);
|
|
void tcp_sock6_iov_init(const struct ctx *c);
|
|
void tcp_flags_flush(const struct ctx *c);
|
|
void tcp_payload_flush(const struct ctx *c);
|
|
int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn);
|
|
int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags);
|
|
|
|
#endif /*TCP_BUF_H */
|