change checksum combination operation to addition
Addition/subtraction has advantages over XOR in that two adds of the same value
don't cancel each other out, and the high bits are better utilized.
diff --git a/openflow_input/bsn_flow_checksum b/openflow_input/bsn_flow_checksum
index 7c92eca..bfa5f3c 100644
--- a/openflow_input/bsn_flow_checksum
+++ b/openflow_input/bsn_flow_checksum
@@ -33,7 +33,7 @@
// Retrieves the checksum for every bucket in a table. The entries are ordered
// by bucket index.
//
-// The checksum of a bucket is the XOR of the cookies of all entries in the
+// The checksum of a bucket is the sum of the cookies of all entries in the
// bucket. Flows are bucketed based on a prefix of the cookie.
struct of_bsn_flow_checksum_bucket_stats_request : of_bsn_stats_request {
uint8_t version;
@@ -68,7 +68,7 @@
// Retrieves the checksum for every table.
//
-// The checksum of a table is the XOR of the cookies of all entries in the
+// The checksum of a table is the sum of the cookies of all entries in the
// table.
struct of_bsn_table_checksum_stats_request : of_bsn_stats_request {
uint8_t version;