X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fodp-util.h;h=57073bad912633416e1623969a07872cc4ed69a6;hb=543a550837f40e39c9f6f110e927b4c230c2d77c;hp=d53f0836ba749bc8704edb839cc02d74b6e5ece3;hpb=44bac24ba5d22fe238bd96702707eb2029efec41;p=openvswitch

diff --git a/lib/odp-util.h b/lib/odp-util.h
index d53f0836..57073bad 100644
--- a/lib/odp-util.h
+++ b/lib/odp-util.h
@@ -32,7 +32,7 @@ struct nlattr;
 struct ofpbuf;
 struct simap;
 
-#define OVSP_NONE ((uint16_t) -1)
+#define OVSP_NONE UINT16_MAX
 
 static inline uint16_t
 ofp_port_to_odp_port(uint16_t ofp_port)
@@ -65,24 +65,38 @@ void format_odp_actions(struct ds *, const struct nlattr *odp_actions,
 int odp_actions_from_string(const char *, const struct simap *port_names,
                             struct ofpbuf *odp_actions);
 
-/* Upper bound on the length of a nlattr-formatted flow key.  The longest
- * nlattr-formatted flow key would be:
+/* The maximum number of bytes that odp_flow_key_from_flow() appends to a
+ * buffer.  This is the upper bound on the length of a nlattr-formatted flow
+ * key that ovs-vswitchd fully understands.
+ *
+ * OVS doesn't insist that ovs-vswitchd and the datapath have exactly the same
+ * idea of a flow, so therefore this value isn't necessarily an upper bound on
+ * the length of a flow key that the datapath can pass to ovs-vswitchd.
+ *
+ * The longest nlattr-formatted flow key appended by odp_flow_key_from_flow()
+ * would be:
  *
  *                         struct  pad  nl hdr  total
  *                         ------  ---  ------  -----
  *  OVS_KEY_ATTR_PRIORITY      4    --     4      8
  *  OVS_KEY_ATTR_TUN_ID        8    --     4     12
+ *  OVS_KEY_ATTR_IPV4_TUNNEL  24    --     4     28
  *  OVS_KEY_ATTR_IN_PORT       4    --     4      8
  *  OVS_KEY_ATTR_ETHERNET     12    --     4     16
+ *  OVS_KEY_ATTR_ETHERTYPE     2     2     4      8  (outer VLAN ethertype)
  *  OVS_KEY_ATTR_8021Q         4    --     4      8
- *  OVS_KEY_ATTR_ETHERTYPE     2     2     4      8
+ *  OVS_KEY_ATTR_ENCAP         0    --     4      4  (VLAN encapsulation)
+ *  OVS_KEY_ATTR_ETHERTYPE     2     2     4      8  (inner VLAN ethertype)
  *  OVS_KEY_ATTR_IPV6         40    --     4     44
  *  OVS_KEY_ATTR_ICMPV6        2     2     4      8
  *  OVS_KEY_ATTR_ND           28    --     4     32
  *  -------------------------------------------------
- *  total                                       144
+ *  total                                       184
+ *
+ * We include some slack space in case the calculation isn't quite right or we
+ * add another field and forget to adjust this value.
  */
-#define ODPUTIL_FLOW_KEY_BYTES 144
+#define ODPUTIL_FLOW_KEY_BYTES 200
 
 /* A buffer with sufficient size and alignment to hold an nlattr-formatted flow
  * key.  An array of "struct nlattr" might not, in theory, be sufficiently