From c8d9d05e7a3b7b30dae6dd4bea0925162c8d8e33 Mon Sep 17 00:00:00 2001
From: Richard Cochran <richardcochran@gmail.com>
Date: Mon, 22 Jan 2018 22:34:26 -0800
Subject: [PATCH] tlv: Implement a memory pool for TLV descriptors.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
---
 msg.c |  3 +++
 tlv.c | 32 ++++++++++++++++++++++++++++++++
 tlv.h | 21 +++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/msg.c b/msg.c
index 6943431..52a59e7 100644
--- a/msg.c
+++ b/msg.c
@@ -213,6 +213,9 @@ void msg_cleanup(void)
 {
 	struct message_storage *s;
 	struct ptp_message *m;
+
+	tlv_extra_cleanup();
+
 	while ((m = TAILQ_FIRST(&msg_pool)) != NULL) {
 		TAILQ_REMOVE(&msg_pool, m, list);
 		s = container_of(m, struct message_storage, msg);
diff --git a/tlv.c b/tlv.c
index a5c2eb3..aa4dafa 100644
--- a/tlv.c
+++ b/tlv.c
@@ -18,6 +18,7 @@
  */
 #include <arpa/inet.h>
 #include <errno.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "port.h"
@@ -29,6 +30,9 @@
 
 uint8_t ieee8021_id[3] = { IEEE_802_1_COMMITTEE };
 
+static TAILQ_HEAD(tlv_pool, tlv_extra) tlv_pool =
+	TAILQ_HEAD_INITIALIZER(tlv_pool);
+
 static void scaled_ns_n2h(ScaledNs *sns)
 {
 	sns->nanoseconds_msb = ntohs(sns->nanoseconds_msb);
@@ -412,6 +416,34 @@ static void org_pre_send(struct organization_tlv *org)
 	}
 }
 
+struct tlv_extra *tlv_extra_alloc(void)
+{
+	struct tlv_extra *extra = TAILQ_FIRST(&tlv_pool);
+
+	if (extra) {
+		TAILQ_REMOVE(&tlv_pool, extra, list);
+	} else {
+		extra = calloc(1, sizeof(*extra));
+	}
+	return extra;
+}
+
+void tlv_extra_cleanup(void)
+{
+	struct tlv_extra *extra;
+
+	while ((extra = TAILQ_FIRST(&tlv_pool)) != NULL) {
+		TAILQ_REMOVE(&tlv_pool, extra, list);
+		free(extra);
+	}
+}
+
+void tlv_extra_recycle(struct tlv_extra *extra)
+{
+	memset(extra, 0, sizeof(*extra));
+	TAILQ_INSERT_HEAD(&tlv_pool, extra, list);
+}
+
 int tlv_post_recv(struct TLV *tlv, struct tlv_extra *extra)
 {
 	int result = 0;
diff --git a/tlv.h b/tlv.h
index c345afe..fd41022 100644
--- a/tlv.h
+++ b/tlv.h
@@ -20,6 +20,8 @@
 #ifndef HAVE_TLV_H
 #define HAVE_TLV_H
 
+#include <sys/queue.h>
+
 #include "ddt.h"
 #include "ds.h"
 
@@ -228,11 +230,30 @@ struct mgmt_clock_description {
 };
 
 struct tlv_extra {
+	TAILQ_ENTRY(tlv_extra) list;
+	struct TLV *tlv;
 	union {
 		struct mgmt_clock_description cd;
 	};
 };
 
+/**
+ * Allocates a new tlv_extra structure.
+ * @return  Pointer to a new structure on success or NULL otherwise.
+ */
+struct tlv_extra *tlv_extra_alloc(void);
+
+/**
+ * Release all of the memory in the tlv_extra cache.
+ */
+void tlv_extra_cleanup(void);
+
+/**
+ * Frees a tlv_extra structure.
+ * @param extra  Pointer to the structure to free.
+ */
+void tlv_extra_recycle(struct tlv_extra *extra);
+
 /**
  * Converts recognized value sub-fields into host byte order.
  * @param tlv Pointer to a Type Length Value field.