nxm_execute_reg_move(const struct ofpact_reg_move *move,
struct flow *flow, struct flow_wildcards *wc)
{
- union mf_subvalue mask_value;
union mf_value src_value;
union mf_value dst_value;
- memset(&mask_value, 0xff, sizeof mask_value);
- mf_write_subfield_flow(&move->dst, &mask_value, &wc->masks);
- mf_write_subfield_flow(&move->src, &mask_value, &wc->masks);
+ mf_mask_field_and_prereqs(move->dst.field, &wc->masks);
+ mf_mask_field_and_prereqs(move->src.field, &wc->masks);
mf_get_value(move->dst.field, flow, &dst_value);
mf_get_value(move->src.field, flow, &src_value);
}
void
-nxm_execute_reg_load(const struct ofpact_reg_load *load, struct flow *flow)
-{
+nxm_execute_reg_load(const struct ofpact_reg_load *load, struct flow *flow,
+ struct flow_wildcards *wc)
+{
+ /* Since at the datapath interface we do not have set actions for
+ * individual fields, but larger sets of fields for a given protocol
+ * layer, the set action will in practice only ever apply to exactly
+ * matched flows for the given protocol layer. For example, if the
+ * reg_load changes the IP TTL, the corresponding datapath action will
+ * rewrite also the IP addresses and TOS byte. Since these other field
+ * values may not be explicitly set, they depend on the incoming flow field
+ * values, and are hence all of them are set in the wildcards masks, when
+ * the action is committed to the datapath. For the rare case, where the
+ * reg_load action does not actually change the value, and no other flow
+ * field values are set (or loaded), the datapath action is skipped, and
+ * no mask bits are set. Such a datapath flow should, however, be
+ * dependent on the specific field value, so the corresponding wildcard
+ * mask bits must be set, lest the datapath flow be applied to packets
+ * containing some other value in the field and the field value remain
+ * unchanged regardless of the incoming value.
+ *
+ * We set the masks here for the whole fields, and their prerequisities.
+ * Even if only the lower byte of a TCP destination port is set,
+ * we set the mask for the whole field, and also the ip_proto in the IP
+ * header, so that the kernel flow would not be applied on, e.g., a UDP
+ * packet, or any other IP protocol in addition to TCP packets.
+ */
+ mf_mask_field_and_prereqs(load->dst.field, &wc->masks);
mf_write_subfield_flow(&load->dst, &load->subvalue, flow);
}