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| | /* 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 */
unsigned flow_count;
union flow flowtab[FLOW_MAX];
/* Last time the flow timers ran */
static struct timespec flow_timer_run;
/** 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_alloc() - Allocate a new flow
*
* Return: pointer to an unused flow entry, or NULL if the table is full
*/
union flow *flow_alloc(void)
{
if (flow_count >= FLOW_MAX)
return NULL;
return &flowtab[flow_count++];
}
/**
* flow_alloc_cancel() - Free a newly allocated flow
* @flow: Flow to deallocate
*
* @flow must be the last flow allocated by flow_alloc()
*/
void flow_alloc_cancel(union flow *flow)
{
ASSERT(FLOW_IDX(flow) == flow_count - 1);
memset(flow, 0, sizeof(*flow));
flow_count--;
}
/**
* flow_table_compact() - Perform compaction on flow table
* @c: Execution context
* @hole: Pointer to recently closed flow
*/
static void flow_table_compact(const struct ctx *c, union flow *hole)
{
union flow *from;
if (FLOW_IDX(hole) == --flow_count) {
debug("flow: table compaction: maximum index was %u (%p)",
FLOW_IDX(hole), (void *)hole);
memset(hole, 0, sizeof(*hole));
return;
}
from = flowtab + 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_defer_handler() - Handler for per-flow deferred and timed tasks
* @c: Execution context
* @now: Current timestamp
*/
void flow_defer_handler(const struct ctx *c, const struct timespec *now)
{
bool timer = false;
union flow *flow;
if (timespec_diff_ms(now, &flow_timer_run) >= FLOW_TIMER_INTERVAL) {
timer = true;
flow_timer_run = *now;
}
for (flow = flowtab + flow_count - 1; flow >= flowtab; flow--) {
bool closed = false;
switch (flow->f.type) {
case FLOW_TCP:
closed = tcp_flow_defer(flow);
break;
case FLOW_TCP_SPLICE:
closed = tcp_splice_flow_defer(flow);
if (!closed && timer)
tcp_splice_timer(c, flow);
break;
default:
/* Assume other flow types don't need any handling */
;
}
if (closed)
flow_table_compact(c, flow);
}
}
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