passt/tcp_splice.h

/* SPDX-License-Identifier: AGPL-3.0-or-later
 * Copyright (c) 2022 Red Hat GmbH
 * Author: Stefano Brivio <sbrivio@redhat.com>
 */

#ifndef TCP_SPLICE_H
#define TCP_SPLICE_H

struct tcp_splice_conn;

void tcp_splice_sock_handler(struct ctx *c, struct tcp_splice_conn *conn,
			     int s, uint32_t events);
bool tcp_splice_conn_from_sock(struct ctx *c, union epoll_ref ref,
			       struct tcp_splice_conn *conn, int s,
			       const struct sockaddr *sa);
void tcp_splice_init(struct ctx *c);

#endif /* TCP_SPLICE_H */
tcp: Refactor to use events instead of states, split out spliced implementation Using events and flags instead of states makes the implementation much more straightforward: actions are mostly centered on events that occurred on the connection rather than states. An example is given by the ESTABLISHED_SOCK_FIN_SENT and FIN_WAIT_1_SOCK_FIN abominations: we don't actually care about which side started closing the connection to handle closing of connection halves. Split out the spliced implementation, as it has very little in common with the "regular" TCP path. Refactor things here and there to improve clarity. Add helpers to trace where resets and flag settings come from. No functional changes intended. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-03-15 01:07:02 +01:00			`/* SPDX-License-Identifier: AGPL-3.0-or-later`
			`* Copyright (c) 2022 Red Hat GmbH`
			`* Author: Stefano Brivio <sbrivio@redhat.com>`
			`*/`

treewide: Add include guards ...at the moment, just for consistency with packet.h, icmp.h, tcp.h and udp.h. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-03-26 00:05:31 +01:00			`#ifndef TCP_SPLICE_H`
			`#define TCP_SPLICE_H`

tcp: Unify part of spliced and non-spliced conn_from_sock path In tcp_sock_handler() we split off to handle spliced sockets before checking anything else. However the first steps of the "new connection" path for each case are the same: allocate a connection entry and accept() the connection. Remove this duplication by making tcp_conn_from_sock() handle both spliced and non-spliced cases, with help from more specific tcp_tap_conn_from_sock and tcp_splice_conn_from_sock functions for the later stages which differ. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-11-17 06:58:51 +01:00			`struct tcp_splice_conn;`

tcp: Remove splice from tcp_epoll_ref Currently the epoll reference for tcp sockets includes a bit indicating whether the socket maps to a spliced connection. However, the reference also has the index of the connection structure which also indicates whether it is spliced. We can therefore avoid the splice bit in the epoll_ref by unifying the first part of the non-spliced and spliced handlers where we look up the connection state. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-11-17 06:58:53 +01:00			`void tcp_splice_sock_handler(struct ctx c, struct tcp_splice_conn conn,`
			`int s, uint32_t events);`
tcp: Use the same sockets to listen for spliced and non-spliced connections In pasta mode, tcp_sock_init[46]() create separate sockets to listen for spliced connections (these are bound to localhost) and non-spliced connections (these are bound to the host address). This introduces a subtle behavioural difference between pasta and passt: by default, pasta will listen only on a single host address, whereas passt will listen on all addresses (0.0.0.0 or ::). This also prevents us using some additional optimizations that only work with the unspecified (0.0.0.0 or ::) address. However, it turns out we don't need to do this. We can splice a connection if and only if it originates from the loopback address. Currently we ensure this by having the "spliced" listening sockets listening only on loopback. Instead, defer the decision about whether to splice a connection until after accept(), by checking if the connection was made from the loopback address. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-11-17 06:58:52 +01:00			`bool tcp_splice_conn_from_sock(struct ctx *c, union epoll_ref ref,`
			`struct tcp_splice_conn *conn, int s,`
			`const struct sockaddr *sa);`
tcp: Refactor to use events instead of states, split out spliced implementation Using events and flags instead of states makes the implementation much more straightforward: actions are mostly centered on events that occurred on the connection rather than states. An example is given by the ESTABLISHED_SOCK_FIN_SENT and FIN_WAIT_1_SOCK_FIN abominations: we don't actually care about which side started closing the connection to handle closing of connection halves. Split out the spliced implementation, as it has very little in common with the "regular" TCP path. Refactor things here and there to improve clarity. Add helpers to trace where resets and flag settings come from. No functional changes intended. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-03-15 01:07:02 +01:00			`void tcp_splice_init(struct ctx *c);`
treewide: Add include guards ...at the moment, just for consistency with packet.h, icmp.h, tcp.h and udp.h. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> 2022-03-26 00:05:31 +01:00
			`#endif /* TCP_SPLICE_H */`