passt/flow_table.h
David Gibson e2e8219f13 flow, tcp: Consolidate flow pointer<->index helpers
Both tcp.c and tcp_splice.c define CONN_IDX() variants to find the index
of their connection structures in the connection table, now become the
unified flow table.  We can easily combine these into a common helper.
While we're there, add some trickery for some additional type safety.

They also define their own CONN() versions, which aren't so easily combined
since they need to return different types, but we can have them use a
common helper.

In the process, we standardise on always using an unsigned type to store
the connection / flow index, which makes more sense.  tcp.c's conn_at_idx()
remains for now, but we change its parameter to unsigned to match.  That in
turn means we can remove a check for negative values from it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-12-04 09:51:04 +01:00

50 lines
1.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright Red Hat
* Author: David Gibson <david@gibson.dropbear.id.au>
*
* Definitions for the global table of packet flows.
*/
#ifndef FLOW_TABLE_H
#define FLOW_TABLE_H
/**
* union flow - Descriptor for a logical packet flow (e.g. connection)
* @f: Fields common between all variants
* @tcp: Fields for non-spliced TCP connections
* @tcp_splice: Fields for spliced TCP connections
*/
union flow {
struct flow_common f;
struct tcp_tap_conn tcp;
struct tcp_splice_conn tcp_splice;
};
/* Global Flow Table */
extern union flow flowtab[];
/** flow_idx - Index of flow from common structure
* @f: Common flow fields pointer
*
* Return: index of @f in the flow table
*/
static inline unsigned flow_idx(const struct flow_common *f)
{
return (union flow *)f - flowtab;
}
/** FLOW_IDX - Find the index of a flow
* @f_: Flow pointer, either union flow * or protocol specific
*
* Return: index of @f in the flow table
*/
#define FLOW_IDX(f_) (flow_idx(&(f_)->f))
/** FLOW - Flow entry at a given index
* @idx: Flow index
*
* Return: pointer to entry @idx in the flow table
*/
#define FLOW(idx) (&flowtab[(idx)])
#endif /* FLOW_TABLE_H */