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passt/flow.c
David Gibson b43e4483ed flow, tcp: Add flow-centric dispatch for deferred flow handling
tcp_defer_handler(), amongst other things, scans the flow table and does
some processing for each TCP connection.  When we add other protocols to
the flow table, they're likely to want some similar scanning.  It makes
more sense for cache friendliness to perform a single scan of the flow
table and dispatch to the protocol specific handlers, rather than having
each protocol separately scan the table.

To that end, add a new flow_defer_handler() handling all flow-linked
deferred operations.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-01-22 23:35:17 +01:00

110 lines
2.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright Red Hat
* Author: David Gibson <david@gibson.dropbear.id.au>
*
* Tracking for logical "flows" of packets.
*/
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include "util.h"
#include "passt.h"
#include "siphash.h"
#include "inany.h"
#include "flow.h"
#include "flow_table.h"
const char *flow_type_str[] = {
[FLOW_TYPE_NONE] = "<none>",
[FLOW_TCP] = "TCP connection",
[FLOW_TCP_SPLICE] = "TCP connection (spliced)",
};
static_assert(ARRAY_SIZE(flow_type_str) == FLOW_NUM_TYPES,
"flow_type_str[] doesn't match enum flow_type");
/* Global Flow Table */
union flow flowtab[FLOW_MAX];
/**
* flow_table_compact() - Perform compaction on flow table
* @c: Execution context
* @hole: Pointer to recently closed flow
*/
void flow_table_compact(struct ctx *c, union flow *hole)
{
union flow *from;
if (FLOW_IDX(hole) == --c->flow_count) {
debug("flow: table compaction: maximum index was %u (%p)",
FLOW_IDX(hole), (void *)hole);
memset(hole, 0, sizeof(*hole));
return;
}
from = flowtab + c->flow_count;
memcpy(hole, from, sizeof(*hole));
switch (from->f.type) {
case FLOW_TCP:
tcp_tap_conn_update(c, &from->tcp, &hole->tcp);
break;
case FLOW_TCP_SPLICE:
tcp_splice_conn_update(c, &hole->tcp_splice);
break;
default:
die("Unexpected %s in tcp_table_compact()",
FLOW_TYPE(&from->f));
}
debug("flow: table compaction (%s): old index %u, new index %u, "
"from: %p, to: %p",
FLOW_TYPE(&from->f), FLOW_IDX(from), FLOW_IDX(hole),
(void *)from, (void *)hole);
memset(from, 0, sizeof(*from));
}
/** flow_log_ - Log flow-related message
* @f: flow the message is related to
* @pri: Log priority
* @fmt: Format string
* @...: printf-arguments
*/
void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
{
char msg[BUFSIZ];
va_list args;
va_start(args, fmt);
(void)vsnprintf(msg, sizeof(msg), fmt, args);
va_end(args);
logmsg(pri, "Flow %u (%s): %s", flow_idx(f), FLOW_TYPE(f), msg);
}
/**
* flow_defer_handler() - Handler for per-flow deferred tasks
* @c: Execution context
*/
void flow_defer_handler(struct ctx *c)
{
union flow *flow;
for (flow = flowtab + c->flow_count - 1; flow >= flowtab; flow--) {
switch (flow->f.type) {
case FLOW_TCP:
tcp_flow_defer(c, flow);
break;
case FLOW_TCP_SPLICE:
tcp_splice_flow_defer(c, flow);
break;
default:
/* Assume other flow types don't need any handling */
;
}
}
}