aboutgitcodebugslistschat
path: root/tcp_conn.h
blob: 20c7cb8b38a254bbc31f5a68d3ac00809f4b731a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
/* 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?
 * @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
 * @faddr:		Guest side forwarding address (guest's remote address)
 * @eport:		Guest side endpoint port (guest's local port)
 * @fport:		Guest side forwarding port (guest's remote 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 */
	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;


	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		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 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 faddr;
	in_port_t	eport;
	in_port_t	fport;

	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;
};

#define SIDES			2
/**
 * struct tcp_splice_conn - Descriptor for a spliced TCP connection
 * @f:			Generic flow information
 * @in_epoll:		Is the connection in the epoll set?
 * @s:			File descriptor for sockets
 * @pipe:		File descriptors for pipes
 * @events:		Events observed/actions performed on connection
 * @flags:		Connection flags (attributes, not events)
 * @read:		Bytes read (not fully written to other side in one shot)
 * @written:		Bytes written (not fully written from one other side read)
*/
struct tcp_splice_conn {
	/* Must be first element */
	struct flow_common f;

	bool in_epoll	:1;
	int s[SIDES];
	int pipe[SIDES][2];

	uint8_t events;
#define SPLICE_CLOSED			0
#define SPLICE_CONNECT			BIT(0)
#define SPLICE_ESTABLISHED		BIT(1)
#define OUT_WAIT_0			BIT(2)
#define OUT_WAIT_1			BIT(3)
#define FIN_RCVD_0			BIT(4)
#define FIN_RCVD_1			BIT(5)
#define FIN_SENT_0			BIT(6)
#define FIN_SENT_1			BIT(7)

	uint8_t flags;
#define SPLICE_V6			BIT(0)
#define RCVLOWAT_SET_0			BIT(1)
#define RCVLOWAT_SET_1			BIT(2)
#define RCVLOWAT_ACT_0			BIT(3)
#define RCVLOWAT_ACT_1			BIT(4)
#define CLOSING				BIT(5)

	uint32_t read[SIDES];
	uint32_t written[SIDES];
};

/* 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(union flow *flow);
bool tcp_splice_flow_defer(union flow *flow);
void tcp_splice_timer(const struct ctx *c, union flow *flow);
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[], sa_family_t af);
void tcp_splice_refill(const struct ctx *c);

#endif /* TCP_CONN_H */