passt/tcp.h
David Gibson 955dd3251c tcp, udp: Don't pre-fill IPv4 destination address in headers
Because packets sent on the tap interface will always be going to the
guest/namespace, we more-or-less know what address they'll be going to.  So
we pre-fill this destination address in our header buffers for IPv4.  We
can't do the same for IPv6 because we could need either the global or
link-local address for the guest.  In future we're going to want more
flexibility for the destination address, so this pre-filling will get in
the way.

Change the flow so we always fill in the IPv4 destination address for each
packet, rather than prefilling it from proto_update_l2_buf().  In fact for
TCP we already redundantly filled the destination for each packet anyway.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-08-22 12:15:33 +02:00

80 lines
2.5 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 */
#define TCP_CONN_INDEX_BITS 17 /* 128k - 1 */
#define TCP_MAX_CONNS MAX_FROM_BITS(TCP_CONN_INDEX_BITS)
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, int af, const void *saddr, const void *daddr,
const struct pool *p, 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 *ts);
void tcp_defer_handler(struct ctx *c);
void tcp_sock_set_bufsize(const struct ctx *c, int s);
void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);
/**
* 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: Port number we're forwarding *to* (listening port plus delta)
* @ns: True if listening within the pasta namespace
* @u32: Opaque u32 value of reference
*/
union tcp_listen_epoll_ref {
struct {
in_port_t port;
bool ns;
};
uint32_t u32;
};
/**
* struct tcp_ctx - Execution context for TCP routines
* @hash_secret: 128-bit secret for hash functions, ISN and hash table
* @conn_count: Count of total connections in connection table
* @splice_conn_count: Count of spliced connections in connection table
* @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 {
uint64_t hash_secret[2];
int conn_count;
int splice_conn_count;
struct port_fwd fwd_in;
struct port_fwd fwd_out;
struct timespec timer_run;
#ifdef HAS_SND_WND
int kernel_snd_wnd;
#endif
size_t pipe_size;
};
#endif /* TCP_H */