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passt/tcp_conn.h
Stefano Brivio ca2749e1bd passt: Relicense to GPL 2.0, or any later version 
In practical terms, passt doesn't benefit from the additional
protection offered by the AGPL over the GPL, because it's not
suitable to be executed over a computer network.

Further, restricting the distribution under the version 3 of the GPL
wouldn't provide any practical advantage either, as long as the passt
codebase is concerned, and might cause unnecessary compatibility
dilemmas.

Change licensing terms to the GNU General Public License Version 2,
or any later version, with written permission from all current and
past contributors, namely: myself, David Gibson, Laine Stump, Andrea
Bolognani, Paul Holzinger, Richard W.M. Jones, Chris Kuhn, Florian
Weimer, Giuseppe Scrivano, Stefan Hajnoczi, and Vasiliy Ulyanov.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-04-06 18:00:33 +02:00

200 lines
6.2 KiB
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/* 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_conn_common - Common fields for spliced and non-spliced
* @spliced: Is this a spliced connection?
* @in_epoll: Is the connection in the epoll set?
*/
struct tcp_conn_common {
bool spliced :1;
bool in_epoll :1;
};
extern const char *tcp_common_flag_str[];
/**
* struct tcp_tap_conn - Descriptor for a TCP connection (not spliced)
* @c: Fields common with tcp_splice_conn
* @next_index: Connection index of next item in hash chain, -1 for none
* @tap_mss: MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
* @sock: Socket descriptor number
* @events: Connection events, implying connection states
* @timer: timerfd descriptor for timeout events
* @flags: Connection flags representing internal attributes
* @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
* @sndbuf: Sending buffer in kernel, rounded to 2 ^ SNDBUF_BITS
* @seq_dup_ack_approx: Last duplicate ACK number sent to tap
* @addr: Remote address (IPv4 or IPv6)
* @tap_port: Guest-facing tap port
* @sock_port: Remote, socket-facing port
* @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 to match tcp_splice_conn */
struct tcp_conn_common c;
int next_index :TCP_CONN_INDEX_BITS + 2;
#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;
int sock :SOCKET_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 timer :SOCKET_REF_BITS;
uint8_t flags;
#define STALLED BIT(0)
#define LOCAL BIT(1)
#define WND_CLAMPED BIT(2)
#define ACTIVE_CLOSE BIT(3)
#define ACK_TO_TAP_DUE BIT(4)
#define ACK_FROM_TAP_DUE BIT(5)
#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))
#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;
union inany_addr addr;
in_port_t tap_port;
in_port_t sock_port;
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_splice_conn - Descriptor for a spliced TCP connection
* @c: Fields common with tcp_tap_conn
* @a: File descriptor number of socket for accepted connection
* @pipe_a_b: Pipe ends for splice() from @a to @b
* @b: File descriptor number of peer connected socket
* @pipe_b_a: Pipe ends for splice() from @b to @a
* @events: Events observed/actions performed on connection
* @flags: Connection flags (attributes, not events)
* @a_read: Bytes read from @a (not fully written to @b in one shot)
* @a_written: Bytes written to @a (not fully written from one @b read)
* @b_read: Bytes read from @b (not fully written to @a in one shot)
* @b_written: Bytes written to @b (not fully written from one @a read)
*/
struct tcp_splice_conn {
/* Must be first element to match tcp_tap_conn */
struct tcp_conn_common c;
int a;
int pipe_a_b[2];
int b;
int pipe_b_a[2];
uint8_t events;
#define SPLICE_CLOSED 0
#define SPLICE_CONNECT BIT(0)
#define SPLICE_ESTABLISHED BIT(1)
#define A_OUT_WAIT BIT(2)
#define B_OUT_WAIT BIT(3)
#define A_FIN_RCVD BIT(4)
#define B_FIN_RCVD BIT(5)
#define A_FIN_SENT BIT(6)
#define B_FIN_SENT BIT(7)
uint8_t flags;
#define SPLICE_V6 BIT(0)
#define RCVLOWAT_SET_A BIT(1)
#define RCVLOWAT_SET_B BIT(2)
#define RCVLOWAT_ACT_A BIT(3)
#define RCVLOWAT_ACT_B BIT(4)
#define CLOSING BIT(5)
uint32_t a_read;
uint32_t a_written;
uint32_t b_read;
uint32_t b_written;
};
/**
* union tcp_conn - Descriptor for a TCP connection (spliced or non-spliced)
* @c: Fields common between all variants
* @tap: Fields specific to non-spliced connections
* @splice: Fields specific to spliced connections
*/
union tcp_conn {
struct tcp_conn_common c;
struct tcp_tap_conn tap;
struct tcp_splice_conn splice;
};
/* TCP connections */
extern union tcp_conn tc[];
/* 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];
void tcp_splice_conn_update(struct ctx *c, struct tcp_splice_conn *new);
void tcp_table_compact(struct ctx *c, union tcp_conn *hole);
void tcp_splice_destroy(struct ctx *c, union tcp_conn *conn_union);
void tcp_splice_timer(struct ctx *c, union tcp_conn *conn_union);
int tcp_conn_pool_sock(int pool[]);
int tcp_conn_new_sock(const struct ctx *c, sa_family_t af);
void tcp_sock_refill_pool(const struct ctx *c, int pool[], int af);
void tcp_splice_refill(const struct ctx *c);
#endif /* TCP_CONN_H */
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