0060acd11b
Flows move over several different states in their lifetime. The rules for these are documented in comments, but they're pretty complex and a number of the transitions are implicit, which makes this pretty fragile and error prone. Change the code to explicitly track the states in a field. Make all transitions explicit and logged. To the extent that it's practical in C, enforce what can and can't be done in various states with ASSERT()s. While we're at it, tweak the docs to clarify the restrictions on each state a bit. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
119 lines
3 KiB
C
119 lines
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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* Definitions for the global table of packet flows.
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*/
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#ifndef FLOW_TABLE_H
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#define FLOW_TABLE_H
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#include "tcp_conn.h"
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#include "icmp_flow.h"
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/**
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* struct flow_free_cluster - Information about a cluster of free entries
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* @f: Generic flow information
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* @n: Number of entries in the free cluster (including this one)
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* @next: Index of next free cluster
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*/
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struct flow_free_cluster {
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/* Must be first element */
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struct flow_common f;
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unsigned n;
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unsigned next;
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};
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/**
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* union flow - Descriptor for a logical packet flow (e.g. connection)
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* @f: Fields common between all variants
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* @tcp: Fields for non-spliced TCP connections
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* @tcp_splice: Fields for spliced TCP connections
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*/
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union flow {
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struct flow_common f;
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struct flow_free_cluster free;
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struct tcp_tap_conn tcp;
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struct tcp_splice_conn tcp_splice;
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struct icmp_ping_flow ping;
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};
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/* Global Flow Table */
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extern unsigned flow_first_free;
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extern union flow flowtab[];
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/** flow_idx - Index of flow from common structure
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* @f: Common flow fields pointer
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*
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* Return: index of @f in the flow table
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*/
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static inline unsigned flow_idx(const struct flow_common *f)
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{
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return (union flow *)f - flowtab;
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}
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/** FLOW_IDX - Find the index of a flow
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* @f_: Flow pointer, either union flow * or protocol specific
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*
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* Return: index of @f in the flow table
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*/
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#define FLOW_IDX(f_) (flow_idx(&(f_)->f))
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/** FLOW - Flow entry at a given index
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* @idx: Flow index
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*
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* Return: pointer to entry @idx in the flow table
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*/
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#define FLOW(idx) (&flowtab[(idx)])
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/** flow_at_sidx - Flow entry for a given sidx
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* @sidx: Flow & side index
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*
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* Return: pointer to the corresponding flow entry, or NULL
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*/
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static inline union flow *flow_at_sidx(flow_sidx_t sidx)
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{
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if (sidx.flow >= FLOW_MAX)
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return NULL;
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return FLOW(sidx.flow);
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}
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/** flow_sidx_t - Index of one side of a flow from common structure
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* @f: Common flow fields pointer
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* @side: Which side to refer to (0 or 1)
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*
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* Return: index of @f and @side in the flow table
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*/
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static inline flow_sidx_t flow_sidx(const struct flow_common *f,
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int side)
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{
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/* cppcheck-suppress [knownConditionTrueFalse, unmatchedSuppression] */
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ASSERT(side == !!side);
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return (flow_sidx_t){
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.side = side,
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.flow = flow_idx(f),
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};
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}
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/** FLOW_SIDX - Find the index of one side of a flow
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* @f_: Flow pointer, either union flow * or protocol specific
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* @side: Which side to index (0 or 1)
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*
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* Return: index of @f and @side in the flow table
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*/
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#define FLOW_SIDX(f_, side) (flow_sidx(&(f_)->f, (side)))
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union flow *flow_alloc(void);
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void flow_alloc_cancel(union flow *flow);
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union flow *flow_set_type(union flow *flow, enum flow_type type,
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unsigned iniside);
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#define FLOW_SET_TYPE(flow_, t_, var_, i_) \
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(&flow_set_type((flow_), (t_), (i_))->var_)
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void flow_activate(struct flow_common *f);
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#define FLOW_ACTIVATE(flow_) \
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(flow_activate(&(flow_)->f))
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#endif /* FLOW_TABLE_H */
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