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0f938c3b9a
Our allocation scheme for flow entries means there are some non-obvious constraints on when what things can be done with an entry. Add a big doc comment explaining the life cycle. In addition, make a FLOW_START() macro to mark one of the important transitions. This encourages correct usage, by making it natural to only access the flow type specific structure after calling it. It also logs that a new flow has been created, which is useful for debugging. We also add logging when a flow's lifecycle ends. This doesn't need a new helper, because it can only happen either from flow_alloc_cancel() or from the flow deferred handler. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
98 lines
2.5 KiB
C
98 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright Red Hat
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* Author: David Gibson <david@gibson.dropbear.id.au>
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*
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* Tracking for logical "flows" of packets.
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*/
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#ifndef FLOW_H
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#define FLOW_H
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#define FLOW_TIMER_INTERVAL 1000 /* ms */
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/**
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* enum flow_type - Different types of packet flows we track
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*/
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enum flow_type {
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/* Represents an invalid or unused flow */
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FLOW_TYPE_NONE = 0,
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/* A TCP connection between a socket and tap interface */
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FLOW_TCP,
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/* A TCP connection between a host socket and ns socket */
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FLOW_TCP_SPLICE,
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FLOW_NUM_TYPES,
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};
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extern const char *flow_type_str[];
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#define FLOW_TYPE(f) \
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((f)->type < FLOW_NUM_TYPES ? flow_type_str[(f)->type] : "?")
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extern const uint8_t flow_proto[];
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#define FLOW_PROTO(f) \
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((f)->type < FLOW_NUM_TYPES ? flow_proto[(f)->type] : 0)
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/**
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* struct flow_common - Common fields for packet flows
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* @type: Type of packet flow
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*/
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struct flow_common {
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uint8_t type;
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};
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#define FLOW_INDEX_BITS 17 /* 128k - 1 */
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#define FLOW_MAX MAX_FROM_BITS(FLOW_INDEX_BITS)
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#define FLOW_TABLE_PRESSURE 30 /* % of FLOW_MAX */
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#define FLOW_FILE_PRESSURE 30 /* % of c->nofile */
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union flow *flow_start(union flow *flow, enum flow_type type,
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unsigned iniside);
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#define FLOW_START(flow_, t_, var_, i_) \
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(&flow_start((flow_), (t_), (i_))->var_)
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/**
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* struct flow_sidx - ID for one side of a specific flow
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* @side: Side referenced (0 or 1)
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* @flow: Index of flow referenced
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*/
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typedef struct flow_sidx {
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unsigned side :1;
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unsigned flow :FLOW_INDEX_BITS;
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} flow_sidx_t;
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static_assert(sizeof(flow_sidx_t) <= sizeof(uint32_t),
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"flow_sidx_t must fit within 32 bits");
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#define FLOW_SIDX_NONE ((flow_sidx_t){ .flow = FLOW_MAX })
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/**
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* flow_sidx_eq() - Test if two sidx values are equal
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* @a, @b: sidx values
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*
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* Return: true iff @a and @b refer to the same side of the same flow
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*/
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static inline bool flow_sidx_eq(flow_sidx_t a, flow_sidx_t b)
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{
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return (a.flow == b.flow) && (a.side == b.side);
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}
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union flow;
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void flow_init(void);
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void flow_defer_handler(const struct ctx *c, const struct timespec *now);
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void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
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__attribute__((format(printf, 3, 4)));
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#define flow_log(f_, pri, ...) flow_log_(&(f_)->f, (pri), __VA_ARGS__)
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#define flow_dbg(f, ...) flow_log((f), LOG_DEBUG, __VA_ARGS__)
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#define flow_err(f, ...) flow_log((f), LOG_ERR, __VA_ARGS__)
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#define flow_trace(f, ...) \
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do { \
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if (log_trace) \
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flow_dbg((f), __VA_ARGS__); \
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} while (0)
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#endif /* FLOW_H */
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