Petri Savolainen(psavol) replied on github web page:
include/odp/api/spec/packet_io.h
line 21
@@ -256,11 +256,27 @@ typedef struct odp_pktio_param_t {
* belong to time synchronization protocol (PTP).
*
* Packet input checksum checking may be enabled or disabled. When it is
- * enabled, implementation will verify checksum correctness on incoming packets
- * and depending on drop configuration either deliver erroneous packets with
- * appropriate flags set (e.g. odp_packet_has_l3_error()) or drop those.
- * When packet dropping is enabled, application will never receive a packet
- * with the specified error and may avoid to check the error flag.
+ * enabled, implementation will attempt to verify checksum correctness on
+ * incoming packets and depending on drop configuration either deliver
erroneous
+ * packets with appropriate flags set (e.g. odp_packet_has_l3_error(),
+ * odp_packet_l3_chksum_status()) or drop those. When packet dropping is
+ * enabled, application will never receive a packet with the specified error
+ * and may avoid to check the error flag.
+ *
+ * If checksum checking is enabled, IPv4 header checksum checking is always
+ * done for packets that do not have IP options and L4 checksum checking
+ * is done for unfragmented packets that do not have IPv4 options or IPv6
+ * extension headers. In other cases checksum checking may or may not
+ * be done. For example, L4 checksum of fragmented packets is typically
+ * not checked.
Comment:
L4 check includes fields from IP header. If the IP header is not in basic form
(has options/extensions) HW may not be able to do the L4 checksum check.
https://github.com/Linaro/odp/pull/167#discussion_r137496343
updated_at 2017-09-07 09:56:13
