71d7985188
In various places we have variables named 'side' or similar which always have the value 0 or 1 (INISIDE or TGTSIDE). Given a flow, this refers to a specific side of it. Upcoming flow table work will make it more useful for "side" to refer to a specific side of a specific flow. To make things less confusing then, prefer the name term "side index" and name 'sidei' for variables with just the 0 or 1 value. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> [sbrivio: Fixed minor detail in comment to struct flow_common] Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
220 lines
7.3 KiB
C
220 lines
7.3 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_state - States of a flow table entry
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*
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* An individual flow table entry moves through these states, usually in this
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* order.
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* General rules:
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* - Code outside flow.c should never write common fields of union flow.
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* - The state field may always be read.
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*
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* FREE - Part of the general pool of free flow table entries
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* Operations:
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* - flow_alloc() finds an entry and moves it to NEW
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*
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* NEW - Freshly allocated, uninitialised entry
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* Operations:
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* - flow_alloc_cancel() returns the entry to FREE
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* - flow_initiate() sets the entry's INISIDE details and moves to
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* INI
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* - FLOW_SET_TYPE() sets the entry's type and moves to TYPED
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* Caveats:
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* - No fields other than state may be accessed
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* - At most one entry may be NEW, INI, TGT or TYPED at a time, so
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* it's unsafe to use flow_alloc() again until this entry moves to
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* ACTIVE or FREE
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* - You may not return to the main epoll loop while any flow is NEW
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*
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* INI - An entry with INISIDE common information completed
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* Operations:
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* - Common fields related to INISIDE may be read
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* - flow_alloc_cancel() returns the entry to FREE
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* - flow_target() sets the entry's TGTSIDE details and moves to TGT
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* Caveats:
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* - Other common fields may not be read
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* - Type specific fields may not be read or written
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* - At most one entry may be NEW, INI, TGT or TYPED at a time, so
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* it's unsafe to use flow_alloc() again until this entry moves to
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* ACTIVE or FREE
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* - You may not return to the main epoll loop while any flow is INI
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*
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* TGT - An entry with only INISIDE and TGTSIDE common information completed
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* Operations:
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* - Common fields related to INISIDE & TGTSIDE may be read
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* - flow_alloc_cancel() returns the entry to FREE
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* - FLOW_SET_TYPE() sets the entry's type and moves to TYPED
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* Caveats:
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* - Other common fields may not be read
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* - Type specific fields may not be read or written
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* - At most one entry may be NEW, INI, TGT or TYPED at a time, so
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* it's unsafe to use flow_alloc() again until this entry moves to
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* ACTIVE or FREE
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* - You may not return to the main epoll loop while any flow is TGT
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*
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* TYPED - Generic info initialised, type specific initialisation underway
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* Operations:
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* - All common fields may be read
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* - Type specific fields may be read and written
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* - flow_alloc_cancel() returns the entry to FREE
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* - FLOW_ACTIVATE() moves the entry to ACTIVE
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* Caveats:
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* - At most one entry may be NEW, INI, TGT or TYPED at a time, so
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* it's unsafe to use flow_alloc() again until this entry moves to
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* ACTIVE or FREE
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* - You may not return to the main epoll loop while any flow is
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* TYPED
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*
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* ACTIVE - An active, fully-initialised flow entry
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* Operations:
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* - All common fields may be read
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* - Type specific fields may be read and written
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* - Flow returns to FREE when it expires, signalled by returning
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* 'true' from flow type specific deferred or timer handler
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* Caveats:
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* - flow_alloc_cancel() may not be called on it
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*/
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enum flow_state {
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FLOW_STATE_FREE,
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FLOW_STATE_NEW,
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FLOW_STATE_INI,
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FLOW_STATE_TGT,
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FLOW_STATE_TYPED,
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FLOW_STATE_ACTIVE,
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FLOW_NUM_STATES,
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};
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#define FLOW_STATE_BITS 8
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static_assert(FLOW_NUM_STATES <= (1 << FLOW_STATE_BITS),
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"Too many flow states for FLOW_STATE_BITS");
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extern const char *flow_state_str[];
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#define FLOW_STATE(f) \
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((f)->state < FLOW_NUM_STATES ? flow_state_str[(f)->state] : "?")
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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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/* ICMP echo requests from guest to host and matching replies back */
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FLOW_PING4,
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/* ICMPv6 echo requests from guest to host and matching replies back */
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FLOW_PING6,
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FLOW_NUM_TYPES,
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};
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#define FLOW_TYPE_BITS 8
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static_assert(FLOW_NUM_TYPES <= (1 << FLOW_TYPE_BITS),
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"Too many flow types for FLOW_TYPE_BITS");
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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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#define SIDES 2
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#define INISIDE 0 /* Initiating side index */
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#define TGTSIDE 1 /* Target side index */
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/**
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* struct flow_common - Common fields for packet flows
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* @state: State of the flow table entry
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* @type: Type of packet flow
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* @pif[]: Interface for each side of the flow
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*/
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struct flow_common {
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#ifdef __GNUC__
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enum flow_state state:FLOW_STATE_BITS;
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enum flow_type type:FLOW_TYPE_BITS;
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#else
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uint8_t state;
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static_assert(sizeof(uint8_t) * 8 >= FLOW_STATE_BITS,
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"Not enough bits for state field");
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uint8_t type;
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static_assert(sizeof(uint8_t) * 8 >= FLOW_TYPE_BITS,
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"Not enough bits for type field");
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#endif
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uint8_t pif[SIDES];
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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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/**
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* struct flow_sidx - ID for one side of a specific flow
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* @sidei: Index of side referenced (0 or 1)
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* @flowi: Index of flow referenced
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*/
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typedef struct flow_sidx {
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unsigned sidei :1;
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unsigned flowi :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){ .flowi = FLOW_MAX })
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/**
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* flow_sidx_valid() - Test if a sidx is valid
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* @sidx: sidx value
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*
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* Return: true if @sidx refers to a valid flow & side
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*/
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static inline bool flow_sidx_valid(flow_sidx_t sidx)
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{
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return sidx.flowi < FLOW_MAX;
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}
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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.flowi == b.flowi) && (a.sidei == b.sidei);
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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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