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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
| | /* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright Red Hat
* Author: David Gibson <david@gibson.dropbear.id.au>
*
* Tracking for logical "flows" of packets.
*/
#ifndef FLOW_H
#define FLOW_H
#define FLOW_TIMER_INTERVAL 1000 /* ms */
/**
* enum flow_state - States of a flow table entry
*
* An individual flow table entry moves through these states, usually in this
* order.
* General rules:
* - Code outside flow.c should never write common fields of union flow.
* - The state field may always be read.
*
* FREE - Part of the general pool of free flow table entries
* Operations:
* - flow_alloc() finds an entry and moves it to NEW state
*
* NEW - Freshly allocated, uninitialised entry
* Operations:
* - flow_alloc_cancel() returns the entry to FREE state
* - flow_initiate() sets the entry's INISIDE details and moves to
* INI state
* - FLOW_SET_TYPE() sets the entry's type and moves to TYPED state
* Caveats:
* - No fields other than state may be accessed.
* - At most one entry may be in NEW, INI, FWD or TYPED state at a
* time, so it's unsafe to use flow_alloc() again until this entry
* moves to ACTIVE or FREE state
* - You may not return to the main epoll loop while an entry is in
* NEW state.
*
* INI - An entry with INISIDE common information completed
* Operations:
* - Common fields related to INISIDE may be read
* - flow_alloc_cancel() returns the entry to FREE state
* - flow_forward() sets the entry's FWDSIDE details and moves to FWD
* state
* Caveats:
* - Other common fields may not be read
* - Type specific fields may not be read or written
* - At most one entry may be in NEW, INI, FWD or TYPED state at a
* time, so it's unsafe to use flow_alloc() again until this entry
* moves to ACTIVE or FREE state
* - You may not return to the main epoll loop while an entry is in
* INI state.
*
* FWD - An entry with only INISIDE and FWDSIDE common information completed
* Operations:
* - Common fields related to INISIDE & FWDSIDE may be read
* - flow_alloc_cancel() returns the entry to FREE state
* - FLOW_SET_TYPE() sets the entry's type and moves to TYPED state
* Caveats:
* - Other common fields may not be read
* - Type specific fields may not be read or written
* - At most one entry may be in NEW, INI, FWD or TYPED state at a
* time, so it's unsafe to use flow_alloc() again until this entry
* moves to ACTIVE or FREE state
* - You may not return to the main epoll loop while an entry is in
* FWD state.
*
* TYPED - Generic info initialised, type specific initialisation underway
* Operations:
* - All common fields may be read
* - Type specific fields may be read and written
* - flow_alloc_cancel() returns the entry to FREE state
* - FLOW_ACTIVATE() moves the entry to ACTIVE state
* Caveats:
* - At most one entry may be in NEW, INI, FWD or TYPED state at a
* time, so it's unsafe to use flow_alloc() again until this entry
* moves to ACTIVE or FREE state
* - You may not return to the main epoll loop while an entry is in
* TYPED state.
*
* ACTIVE - An active, fully-initialised flow entry
* Operations:
* - All common fields may be read
* - Type specific fields may be read and written
* - Flow may be expired by returning 'true' from flow type specific
* deferred or timer handler. This will return it to FREE state.
* Caveats:
* - flow_alloc_cancel() may not be called on it
*/
enum flow_state {
FLOW_STATE_FREE,
FLOW_STATE_NEW,
FLOW_STATE_INI,
FLOW_STATE_FWD,
FLOW_STATE_TYPED,
FLOW_STATE_ACTIVE,
FLOW_NUM_STATES,
};
extern const char *flow_state_str[];
#define FLOW_STATE(f) \
((f)->state < FLOW_NUM_STATES ? flow_state_str[(f)->state] : "?")
/**
* enum flow_type - Different types of packet flows we track
*/
enum flow_type {
/* Represents an invalid or unused flow */
FLOW_TYPE_NONE = 0,
/* A TCP connection between a socket and tap interface */
FLOW_TCP,
/* A TCP connection between a host socket and ns socket */
FLOW_TCP_SPLICE,
/* ICMP echo requests from guest to host and matching replies back */
FLOW_PING4,
/* ICMPv6 echo requests from guest to host and matching replies back */
FLOW_PING6,
FLOW_NUM_TYPES,
};
extern const char *flow_type_str[];
#define FLOW_TYPE(f) \
((f)->type < FLOW_NUM_TYPES ? flow_type_str[(f)->type] : "?")
extern const uint8_t flow_proto[];
#define FLOW_PROTO(f) \
((f)->type < FLOW_NUM_TYPES ? flow_proto[(f)->type] : 0)
#define SIDES 2
#define INISIDE 0 /* Initiating side */
#define FWDSIDE 1 /* Forwarded side */
/**
* struct flow_common - Common fields for packet flows
* @state: State of the flow table entry
* @type: Type of packet flow
* @pif[]: Interface for each side of the flow
*/
struct flow_common {
uint8_t state;
uint8_t type;
uint8_t pif[SIDES];
};
#define FLOW_INDEX_BITS 17 /* 128k - 1 */
#define FLOW_MAX MAX_FROM_BITS(FLOW_INDEX_BITS)
#define FLOW_TABLE_PRESSURE 30 /* % of FLOW_MAX */
#define FLOW_FILE_PRESSURE 30 /* % of c->nofile */
/**
* struct flow_sidx - ID for one side of a specific flow
* @side: Side referenced (0 or 1)
* @flow: Index of flow referenced
*/
typedef struct flow_sidx {
unsigned side :1;
unsigned flow :FLOW_INDEX_BITS;
} flow_sidx_t;
static_assert(sizeof(flow_sidx_t) <= sizeof(uint32_t),
"flow_sidx_t must fit within 32 bits");
#define FLOW_SIDX_NONE ((flow_sidx_t){ .flow = FLOW_MAX })
/**
* flow_sidx_eq() - Test if two sidx values are equal
* @a, @b: sidx values
*
* Return: true iff @a and @b refer to the same side of the same flow
*/
static inline bool flow_sidx_eq(flow_sidx_t a, flow_sidx_t b)
{
return (a.flow == b.flow) && (a.side == b.side);
}
union flow;
void flow_init(void);
void flow_defer_handler(const struct ctx *c, const struct timespec *now);
void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
__attribute__((format(printf, 3, 4)));
#define flow_log(f_, pri, ...) flow_log_(&(f_)->f, (pri), __VA_ARGS__)
#define flow_dbg(f, ...) flow_log((f), LOG_DEBUG, __VA_ARGS__)
#define flow_err(f, ...) flow_log((f), LOG_ERR, __VA_ARGS__)
#define flow_trace(f, ...) \
do { \
if (log_trace) \
flow_dbg((f), __VA_ARGS__); \
} while (0)
#endif /* FLOW_H */
|