8f8eb73482
To implement the TCP hash table, we need an invalid (NULL-like) value for flow_sidx_t. We use FLOW_SIDX_NONE for that, but for defensiveness, we treat (usually) anything with an out of bounds flow index the same way. That's not always done consistently though. In flow_at_sidx() we open code a check on the flow index. In tcp_hash_probe() we instead compare against FLOW_SIDX_NONE, and in some other places we use the fact that flow_at_sidx() will return NULL in this case, even if we don't otherwise need the flow it returns. Clean this up a bit, by adding an explicit flow_sidx_valid() test function. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
120 lines
3 KiB
C
120 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 (!flow_sidx_valid(sidx))
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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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void flow_initiate(union flow *flow, uint8_t pif);
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void flow_target(union flow *flow, uint8_t pif);
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union flow *flow_set_type(union flow *flow, enum flow_type type);
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#define FLOW_SET_TYPE(flow_, t_, var_) (&flow_set_type((flow_), (t_))->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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