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passt/tcp.h
Jon Maloy e63d281871 tcp: leverage support of SO_PEEK_OFF socket option when available
>From linux-6.9.0 the kernel will contain
commit 05ea491641d3 ("tcp: add support for SO_PEEK_OFF socket option").

This new feature makes is possible to call recv_msg(MSG_PEEK) and make
it start reading data from a given offset set by the SO_PEEK_OFF socket
option. This way, we can avoid repeated reading of already read bytes of
a received message, hence saving read cycles when forwarding TCP
messages in the host->name space direction.

In this commit, we add functionality to leverage this feature when
available, while we fall back to the previous behavior when not.

Measurements with iperf3 shows that throughput increases with 15-20
percent in the host->namespace direction when this feature is used.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-07-15 17:57:03 +02:00

75 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (c) 2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef TCP_H
#define TCP_H
#define TCP_TIMER_INTERVAL 1000 /* ms */
struct ctx;
void tcp_timer_handler(struct ctx *c, union epoll_ref ref);
void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
const struct timespec *now);
void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events);
int tcp_tap_handler(struct ctx *c, uint8_t pif, sa_family_t af,
const void *saddr, const void *daddr,
const struct pool *p, int idx, const struct timespec *now);
int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
const char *ifname, in_port_t port);
int tcp_init(struct ctx *c);
void tcp_timer(struct ctx *c, const struct timespec *now);
void tcp_defer_handler(struct ctx *c);
void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);
int tcp_set_peek_offset(int s, int offset);
extern bool peek_offset_cap;
/**
* union tcp_epoll_ref - epoll reference portion for TCP connections
* @index: Index of connection in table
* @u32: Opaque u32 value of reference
*/
union tcp_epoll_ref {
uint32_t index:20;
uint32_t u32;
};
/**
* union tcp_listen_epoll_ref - epoll reference portion for TCP listening
* @port: Bound port number of the socket
* @pif: pif in which the socket is listening
* @u32: Opaque u32 value of reference
*/
union tcp_listen_epoll_ref {
struct {
in_port_t port;
uint8_t pif;
};
uint32_t u32;
};
/**
* struct tcp_ctx - Execution context for TCP routines
* @port_to_tap: Ports bound host-side, packets to tap or spliced
* @fwd_in: Port forwarding configuration for inbound packets
* @fwd_out: Port forwarding configuration for outbound packets
* @timer_run: Timestamp of most recent timer run
* @kernel_snd_wnd: Kernel reports sending window (with commit 8f7baad7f035)
* @pipe_size: Size of pipes for spliced connections
*/
struct tcp_ctx {
struct fwd_ports fwd_in;
struct fwd_ports fwd_out;
struct timespec timer_run;
#ifdef HAS_SND_WND
int kernel_snd_wnd;
#endif
size_t pipe_size;
};
#endif /* TCP_H */