From 96eda13334bcfa11c8e52b617c4e65721226e03c Mon Sep 17 00:00:00 2001
From: vemax78 <devnull@localhost>
Date: Wed, 29 May 2013 22:35:11 +0200
Subject: [PATCH] Fix control & data keep alive message

---
 src/common/capwap_element.c  |  9 ++-------
 src/common/capwap_protocol.c | 19 +++++++++----------
 src/common/capwap_rfc.h      |  6 +++++-
 3 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/src/common/capwap_element.c b/src/common/capwap_element.c
index 7aaf6cd..66f5f22 100644
--- a/src/common/capwap_element.c
+++ b/src/common/capwap_element.c
@@ -148,7 +148,7 @@ int capwap_parsing_packet(struct capwap_packet_rxmng* rxmngpacket, struct capwap
 	memcpy(&rxmngpacket->readpos, &rxmngpacket->readbodypos, sizeof(struct read_block_from_pos));
 
 	if (rxmngpacket->isctrlpacket) {
-		unsigned short bodylength = rxmngpacket->ctrlmsg.length;
+		unsigned short bodylength = rxmngpacket->ctrlmsg.length - CAPWAP_CONTROL_MESSAGE_MIN_LENGTH;
 		while (bodylength > 0) {
 			uint16_t type;
 			uint16_t msglength;
@@ -435,12 +435,7 @@ int capwap_parsing_packet(struct capwap_packet_rxmng* rxmngpacket, struct capwap
 		uint16_t type;
 		uint16_t msglength;
 		struct capwap_message_elements_ops* read_ops;
-		unsigned short bodylength = rxmngpacket->datamsg.length;
-
-		if (!bodylength) {
-			/* TODO */
-			return 1;
-		}
+		unsigned short bodylength = rxmngpacket->datamsg.length - CAPWAP_DATA_MESSAGE_KEEPALIVE_MIN_LENGTH;
 
 		/* Get type and length */
 		rxmngpacket->readerpacketallowed = sizeof(struct capwap_message_element);
diff --git a/src/common/capwap_protocol.c b/src/common/capwap_protocol.c
index bab78d9..f87560b 100644
--- a/src/common/capwap_protocol.c
+++ b/src/common/capwap_protocol.c
@@ -410,7 +410,7 @@ static int capwap_fragment_write_block_from_pos(struct capwap_packet_txmng* txmn
 			fragmentpacket->offset = available + packetpos;
 			if (txmngpacket->isctrlpacket) {
 				txmngpacket->ctrlmsg->length = htons(ntohs(txmngpacket->ctrlmsg->length) + (fragmentpacket->offset - oldoffset));
-			} else {
+			} else if (IS_FLAG_K_HEADER(txmngpacket->header)) {
 				txmngpacket->datamsg->length = htons(ntohs(txmngpacket->datamsg->length) + (fragmentpacket->offset - oldoffset));
 			}
 		}
@@ -557,7 +557,7 @@ struct capwap_packet_txmng* capwap_packet_txmng_create_ctrl_message(struct capwa
 	txmngpacket->ctrlmsg = (struct capwap_control_message*)&fragmentpacket->buffer[fragmentpacket->offset];
 	txmngpacket->ctrlmsg->type = htonl(type);
 	txmngpacket->ctrlmsg->seq = seq;
-	txmngpacket->ctrlmsg->length = 0;
+	txmngpacket->ctrlmsg->length = htons(CAPWAP_CONTROL_MESSAGE_MIN_LENGTH);		/* sizeof(Msg Element Length) + sizeof(Flags) */
 	txmngpacket->ctrlmsg->flags = 0;
 
 	/* Prepare for save capwap element */
@@ -593,14 +593,13 @@ struct capwap_packet_txmng* capwap_packet_txmng_create_data_message(struct capwa
 	fragmentpacket = (struct capwap_fragment_packet_item*)txmngpacket->fragmentlist->last->item;
 	ASSERT((fragmentpacket->offset + sizeof(struct capwap_data_message)) < fragmentpacket->size);
 
-	/* Create message */
+	/* */
 	txmngpacket->isctrlpacket = 0;
-
-	txmngpacket->datamsg = (struct capwap_data_message*)&fragmentpacket->buffer[fragmentpacket->offset];
-	txmngpacket->datamsg->length = 0;
-
-	/* Prepare for save frame */
-	fragmentpacket->offset += sizeof(struct capwap_data_message);
+	if (IS_FLAG_K_HEADER(data)) {
+		txmngpacket->datamsg = (struct capwap_data_message*)&fragmentpacket->buffer[fragmentpacket->offset];
+		txmngpacket->datamsg->length = CAPWAP_DATA_MESSAGE_KEEPALIVE_MIN_LENGTH;
+		fragmentpacket->offset += sizeof(struct capwap_data_message);
+	}
 
 	return txmngpacket;
 }
@@ -834,7 +833,7 @@ static void capwap_packet_rxmng_complete(struct capwap_packet_rxmng* rxmngpacket
 		rxmngpacket->read_ops.read_u8((capwap_message_elements_handle)rxmngpacket, &rxmngpacket->ctrlmsg.seq);
 		rxmngpacket->read_ops.read_u16((capwap_message_elements_handle)rxmngpacket, &rxmngpacket->ctrlmsg.length);
 		rxmngpacket->read_ops.read_u8((capwap_message_elements_handle)rxmngpacket, &rxmngpacket->ctrlmsg.flags);
-	} else {
+	} else if (IS_FLAG_K_HEADER(rxmngpacket->header)) {
 		rxmngpacket->readerpacketallowed = sizeof(struct capwap_data_message);
 		rxmngpacket->read_ops.read_u16((capwap_message_elements_handle)rxmngpacket, &rxmngpacket->datamsg.length);
 	}
diff --git a/src/common/capwap_rfc.h b/src/common/capwap_rfc.h
index 2724b7a..c1a7322 100644
--- a/src/common/capwap_rfc.h
+++ b/src/common/capwap_rfc.h
@@ -118,6 +118,8 @@ struct capwap_message_element {
 #define CAPWAP_LAST_MESSAGE_TYPE					26
 
 /* Control Message */
+#define CAPWAP_CONTROL_MESSAGE_MIN_LENGTH			3
+
 struct capwap_control_message {
 	uint32_t type;
 	uint8_t seq;
@@ -126,7 +128,9 @@ struct capwap_control_message {
 	int8_t elements[0];
 } STRUCT_PACKED;
 
-/* Data Message */
+/* Data Message Keep-Alive*/
+#define CAPWAP_DATA_MESSAGE_KEEPALIVE_MIN_LENGTH	2
+
 struct capwap_data_message {
 	uint16_t length;
 	int8_t elements[0];