mirror of
https://passt.top/passt
synced 2024-06-30 06:52:40 +00:00
8981a720aa
Currently we always keep the flow table maximally compact: that is all the active entries are contiguous at the start of the table. Doing this sometimes requires moving an entry when one is freed. That's kind of fiddly, and potentially expensive: it requires updating the hash table for the new location, and depending on flow type, it may require EPOLL_CTL_MOD, system calls to update epoll tags with the new location too. Implement a new way of managing the flow table that doesn't ever move entries. It attempts to maintain some compactness by always using the first free slot for a new connection, and mitigates the effect of non compactness by cheaply skipping over contiguous blocks of free entries. See the "theory of operation" comment in flow.c for details. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>b [sbrivio: additional ASSERT(flow_first_free <= FLOW_MAX - 2) to avoid Coverity Scan false positive] Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/* 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_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,
|
|
|
|
FLOW_NUM_TYPES,
|
|
};
|
|
|
|
extern const char *flow_type_str[];
|
|
#define FLOW_TYPE(f) \
|
|
((f)->type < FLOW_NUM_TYPES ? flow_type_str[(f)->type] : "?")
|
|
|
|
/**
|
|
* struct flow_common - Common fields for packet flows
|
|
* @type: Type of packet flow
|
|
*/
|
|
struct flow_common {
|
|
uint8_t type;
|
|
};
|
|
|
|
#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 */
|