[Ocfs2-tools-devel] [PATCH 1/1] wireshark-ocfs2: add dlm_query_join response handler

[Sunil Mushran]

Comment inline.

Jeff Liu wrote:
>  this patch add the handler against dlm_query_join_response message, it
>  could deal with both ocfs2-1.2.x and the newer packet layout.
>
>  for ocfs2-1.4.x and the newer, the response status will be dissected and shown as:
> 	 Status: Value (response_code:dlm_minor:fs_minor)
>
> Signed-off-by: Jeff Liu <jeff.liu at oracle.com>
> ---
>  epan/dissectors/packet-ocfs2.c |   54 +++++++++++++++++++++++++++++++++++++--
>  1 files changed, 51 insertions(+), 3 deletions(-)
>
> diff --git a/epan/dissectors/packet-ocfs2.c b/epan/dissectors/packet-ocfs2.c
> index ce57c3f..a4f07cc 100644
> --- a/epan/dissectors/packet-ocfs2.c
> +++ b/epan/dissectors/packet-ocfs2.c
> @@ -229,12 +229,27 @@ const char * decode_enumerated_bitfield_full(guint32 val, guint32 mask, int widt
>  #define DLM_LVB_LEN  64
>  #define DLM_MOD_KEY (0x666c6172)
>  
> -enum dlm_query_join_response {
> +enum dlm_query_join_response_code {
>  	JOIN_DISALLOW = 0,
>  	JOIN_OK,
>  	JOIN_OK_NO_MAP,
> +	JOIN_PROTOCOL_MISMATCH,
>  };
>  
> +struct dlm_query_join_packet {
> +	guint8 code;		/* Response code. dlm_minor and fs_minor
> +				 are only valid if this is JOIN_OK */
> +	guint8 dlm_minor;	/* The minor version of the protocol the
> +				dlm is speaking. */
> +	guint8 fs_minor;	/* The minor version of the protocol the
> +				filesystem is speaking. */
> +	guint8 reserved;
> +};
> +
> +union dlm_query_join_response {
> +	guint32 intval;
> +	struct dlm_query_join_packet packet;
> +};
>  
>  /* DLM lock modes */
>  enum {
> @@ -1148,10 +1163,37 @@ static void msg_struct_enumerate_fields(struct dlm_msg_struct_def *def, proto_tr
>  	}
>  }
>  
> +static void dissect_dlm_query_join_response(proto_tree *tree,
> +					    proto_item *item,
> +					    tvbuff_t *tvb,
> +					    int offset)
> +{
> +	union dlm_query_join_response response;
> +	struct dlm_query_join_packet packet;
> +	guint32 status;
> +
> +	status = tvb_get_ntohl(tvb, offset);
> +
> +	/* NOP if ocfs2-1.2.x message coming */
> +	if (status < JOIN_PROTOCOL_MISMATCH)
> +		return ;
>   

Not sure I understand this. Can't you key off the size of the packet?

> +
> +	/* for ocfs2-1.4.x and newer */
> +	response.intval = htonl(status);
> +	packet = response.packet;
> +	proto_item_append_text(item, " (%u:", packet.code);
> +
> +	if (packet.code == JOIN_OK)
> +		proto_item_append_text(item, "%u:%u",
> +					packet.dlm_minor, packet.fs_minor);
> +
> +	proto_item_append_text(item, ")");
> +}
> +
>  static int dissect_ocfs2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
>  {
>  	proto_tree *subtree = NULL;
> -	proto_item *ti;
> +	proto_item *ti, *si;
>  	guint16 len, magic, msg_type;
>  	int ret;
>  
> @@ -1188,7 +1230,7 @@ static int dissect_ocfs2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
>  		proto_tree_add_item(subtree, hf_msg_sys_status,
>  				    tvb, O2NET_MSG_HDR_OFF_SYS_STATUS, 4,
>  				    FALSE);
> -		proto_tree_add_item(subtree, hf_msg_status,
> +		si = proto_tree_add_item(subtree, hf_msg_status,
>  				    tvb, O2NET_MSG_HDR_OFF_STATUS, 4,
>  				    FALSE);
>  		proto_tree_add_item(subtree, hf_msg_key,
> @@ -1240,6 +1282,12 @@ static int dissect_ocfs2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
>  			}
>  		}
>  
> +		if (msg_type == DLM_QUERY_JOIN_MSG) {
> +			if (magic == O2NET_MSG_STATUS_MAGIC)
> +				dissect_dlm_query_join_response(subtree,
> +					si, tvb, O2NET_MSG_HDR_OFF_STATUS);
> +			goto out;
> +		}
>  
>  		if (magic == O2NET_MSG_MAGIC) {
>  			struct dlm_msg_struct_def *def;
>