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passt/tcp_conn.h
David Gibson ba0823f8a0 tcp: Don't pass both flow pointer and flow index
tcp_flow_migrate_source_ext() is passed both the index of the flow it
operates on and the pointer to the connection structure.  However, the
former is trivially derived from the latter.  Simplify the interface.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2025-02-18 13:33:10 +01:00

251 lines
8.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright Red Hat
* Author: Stefano Brivio <sbrivio@redhat.com>
* Author: David Gibson <david@gibson.dropbear.id.au>
*
* TCP connection tracking data structures, used by tcp.c and
* tcp_splice.c. Shouldn't be included in non-TCP code.
*/
#ifndef TCP_CONN_H
#define TCP_CONN_H
/**
* struct tcp_tap_conn - Descriptor for a TCP connection (not spliced)
* @f: Generic flow information
* @in_epoll: Is the connection in the epoll set?
* @retrans: Number of retransmissions occurred due to ACK_TIMEOUT
* @ws_from_tap: Window scaling factor advertised from tap/guest
* @ws_to_tap: Window scaling factor advertised to tap/guest
* @tap_mss: MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
* @sock: Socket descriptor number
* @events: Connection events, implying connection states
* @listening_sock: Listening socket this socket was accept()ed from, or -1
* @timer: timerfd descriptor for timeout events
* @flags: Connection flags representing internal attributes
* @sndbuf: Sending buffer in kernel, rounded to 2 ^ SNDBUF_BITS
* @seq_dup_ack_approx: Last duplicate ACK number sent to tap
* @wnd_from_tap: Last window size from tap, unscaled (as received)
* @wnd_to_tap: Sending window advertised to tap, unscaled (as sent)
* @seq_to_tap: Next sequence for packets to tap
* @seq_ack_from_tap: Last ACK number received from tap
* @seq_from_tap: Next sequence for packets from tap (not actually sent)
* @seq_ack_to_tap: Last ACK number sent to tap
* @seq_init_from_tap: Initial sequence number from tap
*/
struct tcp_tap_conn {
/* Must be first element */
struct flow_common f;
bool in_epoll :1;
#define TCP_RETRANS_BITS 3
unsigned int retrans :TCP_RETRANS_BITS;
#define TCP_MAX_RETRANS MAX_FROM_BITS(TCP_RETRANS_BITS)
#define TCP_WS_BITS 4 /* RFC 7323 */
#define TCP_WS_MAX 14
unsigned int ws_from_tap :TCP_WS_BITS;
unsigned int ws_to_tap :TCP_WS_BITS;
#define TCP_MSS_BITS 14
unsigned int tap_mss :TCP_MSS_BITS;
#define MSS_SET(conn, mss) (conn->tap_mss = (mss >> (16 - TCP_MSS_BITS)))
#define MSS_GET(conn) (conn->tap_mss << (16 - TCP_MSS_BITS))
int sock :FD_REF_BITS;
uint8_t events;
#define CLOSED 0
#define SOCK_ACCEPTED BIT(0) /* implies SYN sent to tap */
#define TAP_SYN_RCVD BIT(1) /* implies socket connecting */
#define TAP_SYN_ACK_SENT BIT( 3) /* implies socket connected */
#define ESTABLISHED BIT(2)
#define SOCK_FIN_RCVD BIT( 3)
#define SOCK_FIN_SENT BIT( 4)
#define TAP_FIN_RCVD BIT( 5)
#define TAP_FIN_SENT BIT( 6)
#define TAP_FIN_ACKED BIT( 7)
#define CONN_STATE_BITS /* Setting these clears other flags */ \
(SOCK_ACCEPTED | TAP_SYN_RCVD | ESTABLISHED)
int listening_sock;
int timer :FD_REF_BITS;
uint8_t flags;
#define STALLED BIT(0)
#define LOCAL BIT(1)
#define ACTIVE_CLOSE BIT(2)
#define ACK_TO_TAP_DUE BIT(3)
#define ACK_FROM_TAP_DUE BIT(4)
#define ACK_FROM_TAP_BLOCKS BIT(5)
#define SNDBUF_BITS 24
unsigned int sndbuf :SNDBUF_BITS;
#define SNDBUF_SET(conn, bytes) (conn->sndbuf = ((bytes) >> (32 - SNDBUF_BITS)))
#define SNDBUF_GET(conn) (conn->sndbuf << (32 - SNDBUF_BITS))
uint8_t seq_dup_ack_approx;
uint16_t wnd_from_tap;
uint16_t wnd_to_tap;
uint32_t seq_to_tap;
uint32_t seq_ack_from_tap;
uint32_t seq_from_tap;
uint32_t seq_ack_to_tap;
uint32_t seq_init_from_tap;
};
/**
* struct tcp_tap_transfer - Migrated TCP data, flow table part, network order
* @pif: Interfaces for each side of the flow
* @side: Addresses and ports for each side of the flow
* @retrans: Number of retransmissions occurred due to ACK_TIMEOUT
* @ws_from_tap: Window scaling factor advertised from tap/guest
* @ws_to_tap: Window scaling factor advertised to tap/guest
* @events: Connection events, implying connection states
* @tap_mss: MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
* @sndbuf: Sending buffer in kernel, rounded to 2 ^ SNDBUF_BITS
* @flags: Connection flags representing internal attributes
* @seq_dup_ack_approx: Last duplicate ACK number sent to tap
* @wnd_from_tap: Last window size from tap, unscaled (as received)
* @wnd_to_tap: Sending window advertised to tap, unscaled (as sent)
* @seq_to_tap: Next sequence for packets to tap
* @seq_ack_from_tap: Last ACK number received from tap
* @seq_from_tap: Next sequence for packets from tap (not actually sent)
* @seq_ack_to_tap: Last ACK number sent to tap
* @seq_init_from_tap: Initial sequence number from tap
*/
struct tcp_tap_transfer {
uint8_t pif[SIDES];
struct flowside side[SIDES];
uint8_t retrans;
uint8_t ws_from_tap;
uint8_t ws_to_tap;
uint8_t events;
uint32_t tap_mss;
uint32_t sndbuf;
uint8_t flags;
uint8_t seq_dup_ack_approx;
uint16_t wnd_from_tap;
uint16_t wnd_to_tap;
uint32_t seq_to_tap;
uint32_t seq_ack_from_tap;
uint32_t seq_from_tap;
uint32_t seq_ack_to_tap;
uint32_t seq_init_from_tap;
} __attribute__((packed, aligned(__alignof__(uint32_t))));
/**
* struct tcp_tap_transfer_ext - Migrated TCP data, outside flow, network order
* @seq_snd: Socket-side send sequence
* @seq_rcv: Socket-side receive sequence
* @sndq: Length of pending send queue (unacknowledged / not sent)
* @notsent: Part of pending send queue that wasn't sent out yet
* @rcvq: Length of pending receive queue
* @mss: Socket-side MSS clamp
* @snd_wl1: Next sequence used in window probe (next sequence - 1)
* @snd_wnd: Socket-side sending window
* @max_window: Window clamp
* @rcv_wnd: Socket-side receive window
* @rcv_wup: rcv_nxt on last window update sent
* @snd_ws: Window scaling factor, send
* @rcv_ws: Window scaling factor, receive
* @tcpi_state: Connection state in TCP_INFO style (enum, tcp_states.h)
* @tcpi_options: TCPI_OPT_* constants (timestamps, selective ACK)
*/
struct tcp_tap_transfer_ext {
uint32_t seq_snd;
uint32_t seq_rcv;
uint32_t sndq;
uint32_t notsent;
uint32_t rcvq;
uint32_t mss;
/* We can't just use struct tcp_repair_window: we need network order */
uint32_t snd_wl1;
uint32_t snd_wnd;
uint32_t max_window;
uint32_t rcv_wnd;
uint32_t rcv_wup;
uint8_t snd_ws;
uint8_t rcv_ws;
uint8_t tcpi_state;
uint8_t tcpi_options;
} __attribute__((packed, aligned(__alignof__(uint32_t))));
/**
* struct tcp_splice_conn - Descriptor for a spliced TCP connection
* @f: Generic flow information
* @s: File descriptor for sockets
* @pipe: File descriptors for pipes
* @read: Bytes read (not fully written to other side in one shot)
* @written: Bytes written (not fully written from one other side read)
* @events: Events observed/actions performed on connection
* @flags: Connection flags (attributes, not events)
* @in_epoll: Is the connection in the epoll set?
*/
struct tcp_splice_conn {
/* Must be first element */
struct flow_common f;
int s[SIDES];
int pipe[SIDES][2];
uint32_t read[SIDES];
uint32_t written[SIDES];
uint8_t events;
#define SPLICE_CLOSED 0
#define SPLICE_CONNECT BIT(0)
#define SPLICE_ESTABLISHED BIT(1)
#define OUT_WAIT(sidei_) ((sidei_) ? BIT(3) : BIT(2))
#define FIN_RCVD(sidei_) ((sidei_) ? BIT(5) : BIT(4))
#define FIN_SENT(sidei_) ((sidei_) ? BIT(7) : BIT(6))
uint8_t flags;
#define RCVLOWAT_SET(sidei_) ((sidei_) ? BIT(1) : BIT(0))
#define RCVLOWAT_ACT(sidei_) ((sidei_) ? BIT(3) : BIT(2))
#define CLOSING BIT(4)
bool in_epoll :1;
};
/* Socket pools */
#define TCP_SOCK_POOL_SIZE 32
extern int init_sock_pool4 [TCP_SOCK_POOL_SIZE];
extern int init_sock_pool6 [TCP_SOCK_POOL_SIZE];
bool tcp_flow_defer(const struct tcp_tap_conn *conn);
int tcp_flow_repair_on(struct ctx *c, const struct tcp_tap_conn *conn);
int tcp_flow_repair_off(struct ctx *c, const struct tcp_tap_conn *conn);
int tcp_flow_migrate_source(int fd, struct tcp_tap_conn *conn);
int tcp_flow_migrate_source_ext(int fd, const struct tcp_tap_conn *conn);
int tcp_flow_migrate_target(struct ctx *c, int fd);
int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd);
bool tcp_flow_is_established(const struct tcp_tap_conn *conn);
bool tcp_splice_flow_defer(struct tcp_splice_conn *conn);
void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn);
int tcp_conn_pool_sock(int pool[]);
int tcp_conn_sock(sa_family_t af);
int tcp_sock_refill_pool(int pool[], sa_family_t af);
void tcp_splice_refill(const struct ctx *c);
#endif /* TCP_CONN_H */