From: Alan T. DeKok <aland@freeradius.org>
Date: Mon, 23 Apr 2018 18:44:04 +0000 (-0400)
Subject: add packet comparison function
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c997cde030efbfd5199bd217bcc4741a7eca70f;p=thirdparty%2Ffreeradius-server.git

add packet comparison function

for doing dedup
---

diff --git a/src/lib/io/application.h b/src/lib/io/application.h
index 1d5b6c8afb6..7c7e4fd1949 100644
--- a/src/lib/io/application.h
+++ b/src/lib/io/application.h
@@ -111,5 +111,6 @@ typedef struct fr_app_io_t {
 	fr_io_signal_t			error;		//!< There was an error on the socket.
 	fr_io_open_t			close;		//!< Close the transport.
 	fr_io_nak_t			nak;		//!< Function to send a NAK.
+	fr_io_data_cmp_t		compare;	//!< compare two packets
 	void				*private;	//!< any private APIs it needs to export.
 } fr_app_io_t;
diff --git a/src/lib/io/io.h b/src/lib/io/io.h
index 2e48f506e91..797dc315f91 100644
--- a/src/lib/io/io.h
+++ b/src/lib/io/io.h
@@ -255,6 +255,32 @@ typedef int (*fr_io_data_inject_t)(void *instance,uint8_t *buffer, size_t buffer
  */
 typedef void (*fr_io_data_vnode_t)(void *instance, uint32_t fflags);
 
+/** Compare two packets for storing in a duplicate detection tree.
+ *
+ * We presume that the packets are well formed.
+ *
+ * The comparison should be stable.  i.e. compare the packets a field
+ * at a time.  If the field is different, return the result from that
+ * field.
+ *
+ * The comparison order of the fields should be "very different" to
+ * "much the same".  The packets are put into an rbtree, so having a
+ * large fanout at the top is useful.
+ *
+ * Note that this function should not check if the packets are
+ * completely identical.  Instead, if checks whether or not the
+ * packets take the same place in any dedup tree.
+ *
+ * @param[in] instance		the context for this function
+ * @param[in] packet1		one packet
+ * @param[in] packet2		a second packet
+ * @return
+ *	- <0 on packet one "smaller" than packet two
+ *	- >0 on packet two "larger" than packet one
+ *	- =0 on the two packets being identical
+ */
+typedef int (*fr_io_data_cmp_t)(void const *instance, void const *packet1, void const *packet2);
+
 /**  Handle a close or error on the socket.
  *
  *  In general, the only thing to do on errors is to close the