passt/flow.c
David Gibson eb8b1a233b flow, tcp: Add logging helpers for connection related messages
Most of the messages logged by the TCP code (be they errors, debug or
trace messages) are related to a specific connection / flow.  We're fairly
consistent about prefixing these with the type of connection and the
connection / flow index.  However there are a few places where we put the
index later in the message or omit it entirely.  The template with the
prefix is also a little bulky to carry around for every message,
particularly for spliced connections.

To help keep this consistent, introduce some helpers to log messages
linked to a specific flow.  It takes the flow as a parameter and adds a
uniform prefix to each message.  This makes things slightly neater now, but
more importantly will help keep formatting consistent as we add more things
to the flow table.

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

86 lines
2 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 <unistd.h>
#include <string.h>
#include "util.h"
#include "passt.h"
#include "siphash.h"
#include "inany.h"
#include "flow.h"
#include "tcp_conn.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);
}