icmp: Store ping socket information in flow table

Currently icmp_id_map[][] stores information about ping sockets in a
bespoke structure.  Move the same information into new types of flow
in the flow table.  To match that change, replace the existing ICMP
timer with a flow-based timer for expiring ping sockets.  This has the
advantage that we only need to scan the active flows, not all possible
ids.

We convert icmp_id_map[][] to point to the flow table entries, rather
than containing its own information.  We do still use that array for
locating the right ping flows, rather than using a "flow native" form
of lookup for the time being.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Update id_sock description in comment to icmp_ping_new()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/icmp_flow.h b/icmp_flow.h
new file mode 100644
index 0000000..5a2eed9
--- /dev/null
+++ b/icmp_flow.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright Red Hat
+ * Author: David Gibson <david@gibson.dropbear.id.au>
+ *
+ * ICMP flow tracking data structures
+ */
+#ifndef ICMP_FLOW_H
+#define ICMP_FLOW_H
+
+/**
+ * struct icmp_ping_flow - Descriptor for a flow of ping requests/replies
+ * @f:		Generic flow information
+ * @seq:	Last sequence number sent to tap, host order, -1: not sent yet
+ * @sock:	"ping" socket
+ * @ts:		Last associated activity from tap, seconds
+ * @id:		ICMP id for the flow as seen by the guest
+ */
+struct icmp_ping_flow {
+	/* Must be first element */
+	struct flow_common f;
+
+	int seq;
+	int sock;
+	time_t ts;
+	uint16_t id;
+};
+
+bool icmp_ping_timer(const struct ctx *c, union flow *flow,
+		     const struct timespec *now);
+
+#endif /* ICMP_FLOW_H */