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672d786de1
Currently, if a non-SYN TCP packet arrives which doesn't match any existing connection, we simply ignore it. However RFC 9293, section 3.10.7.1 says we should respond with an RST to a non-SYN, non-RST packet that's for a CLOSED (i.e. non-existent) connection. This can arise in practice with migration, in cases where some error means we have to discard a connection. We destroy the connection with tcp_rst() in that case, but because the guest is stopped, we may not be able to deliver the RST packet on the tap interface immediately. This change ensures an RST will be sent if the guest tries to use the connection again. A similar situation can arise if a passt/pasta instance is killed or crashes, but is then replaced with another attached to the same guest. This can leave the guest with stale connections that the new passt instance isn't aware of. It's better to send an RST so the guest knows quickly these are broken, rather than letting them linger until they time out. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
71 lines
2 KiB
C
71 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#ifndef TCP_H
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#define TCP_H
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#define TCP_TIMER_INTERVAL 1000 /* ms */
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struct ctx;
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void tcp_timer_handler(const struct ctx *c, union epoll_ref ref);
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void tcp_listen_handler(const struct ctx *c, union epoll_ref ref,
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const struct timespec *now);
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void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
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uint32_t events);
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int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
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const void *saddr, const void *daddr, uint32_t flow_lbl,
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const struct pool *p, int idx, const struct timespec *now);
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int tcp_sock_init(const struct ctx *c, const union inany_addr *addr,
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const char *ifname, in_port_t port);
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int tcp_init(struct ctx *c);
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void tcp_timer(struct ctx *c, const struct timespec *now);
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void tcp_defer_handler(struct ctx *c);
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void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);
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int tcp_set_peek_offset(int s, int offset);
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extern bool peek_offset_cap;
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/**
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* union tcp_epoll_ref - epoll reference portion for TCP connections
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* @index: Index of connection in table
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* @u32: Opaque u32 value of reference
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*/
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union tcp_epoll_ref {
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uint32_t index:20;
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uint32_t u32;
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};
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/**
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* union tcp_listen_epoll_ref - epoll reference portion for TCP listening
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* @port: Bound port number of the socket
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* @pif: pif in which the socket is listening
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* @u32: Opaque u32 value of reference
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*/
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union tcp_listen_epoll_ref {
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struct {
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in_port_t port;
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uint8_t pif;
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};
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uint32_t u32;
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};
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/**
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* struct tcp_ctx - Execution context for TCP routines
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* @port_to_tap: Ports bound host-side, packets to tap or spliced
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* @fwd_in: Port forwarding configuration for inbound packets
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* @fwd_out: Port forwarding configuration for outbound packets
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* @timer_run: Timestamp of most recent timer run
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* @pipe_size: Size of pipes for spliced connections
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*/
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struct tcp_ctx {
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struct fwd_ports fwd_in;
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struct fwd_ports fwd_out;
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struct timespec timer_run;
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size_t pipe_size;
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};
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#endif /* TCP_H */
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