+\f
+/* flow_wildcards functions. */
+
+/* Given the wildcard bit count in bits 'shift' through 'shift + 5' (inclusive)
+ * of 'wildcards', returns a 32-bit bit mask with a 1 in each bit that must
+ * match and a 0 in each bit that is wildcarded.
+ *
+ * The bits in 'wildcards' are in the format used in enum ofp_flow_wildcards: 0
+ * is exact match, 1 ignores the LSB, 2 ignores the 2 least-significant bits,
+ * ..., 32 and higher wildcard the entire field. This is the *opposite* of the
+ * usual convention where e.g. /24 indicates that 8 bits (not 24 bits) are
+ * wildcarded. */
+ovs_be32
+flow_nw_bits_to_mask(uint32_t wildcards, int shift)
+{
+ wildcards = (wildcards >> shift) & 0x3f;
+ return wildcards < 32 ? htonl(~((1u << wildcards) - 1)) : 0;
+}
+
+/* Return 'wildcards' in "normal form":
+ *
+ * - Forces unknown bits to 0.
+ *
+ * - Forces nw_src and nw_dst masks greater than 32 to exactly 32.
+ */
+static inline uint32_t
+flow_wildcards_normalize(uint32_t wildcards)
+{
+ wildcards &= wildcards & OVSFW_ALL;
+ if (wildcards & (0x20 << OFPFW_NW_SRC_SHIFT)) {
+ wildcards &= ~(0x1f << OFPFW_NW_SRC_SHIFT);
+ }
+ if (wildcards & (0x20 << OFPFW_NW_DST_SHIFT)) {
+ wildcards &= ~(0x1f << OFPFW_NW_DST_SHIFT);
+ }
+ return wildcards;
+}
+
+/* Initializes 'wc' from 'wildcards', which may be any combination of the
+ * OFPFW_* and OVSFW_* wildcard bits. */
+void
+flow_wildcards_init(struct flow_wildcards *wc, uint32_t wildcards)
+{
+ wc->wildcards = flow_wildcards_normalize(wildcards);
+ wc->nw_src_mask = flow_nw_bits_to_mask(wc->wildcards, OFPFW_NW_SRC_SHIFT);
+ wc->nw_dst_mask = flow_nw_bits_to_mask(wc->wildcards, OFPFW_NW_DST_SHIFT);
+}
+
+/* Initializes 'wc' as an exact-match set of wildcards; that is, 'wc' does not
+ * wildcard any bits or fields. */
+void
+flow_wildcards_init_exact(struct flow_wildcards *wc)
+{
+ flow_wildcards_init(wc, 0);
+}
+
+static inline uint32_t
+combine_nw_bits(uint32_t wb1, uint32_t wb2, int shift)
+{
+ uint32_t sb1 = (wb1 >> shift) & 0x3f;
+ uint32_t sb2 = (wb2 >> shift) & 0x3f;
+ return MAX(sb1, sb2) << shift;
+}
+
+/* Initializes 'dst' as the combination of wildcards in 'src1' and 'src2'.
+ * That is, a bit or a field is wildcarded in 'dst' if it is wildcarded in
+ * 'src1' or 'src2' or both. */
+void
+flow_wildcards_combine(struct flow_wildcards *dst,
+ const struct flow_wildcards *src1,
+ const struct flow_wildcards *src2)
+{
+ uint32_t wb1 = src1->wildcards;
+ uint32_t wb2 = src2->wildcards;
+
+ dst->wildcards = (wb1 | wb2) & ~(OFPFW_NW_SRC_MASK | OFPFW_NW_DST_MASK);
+ dst->wildcards |= combine_nw_bits(wb1, wb2, OFPFW_NW_SRC_SHIFT);
+ dst->wildcards |= combine_nw_bits(wb1, wb2, OFPFW_NW_DST_SHIFT);
+ dst->nw_src_mask = src1->nw_src_mask & src2->nw_src_mask;
+ dst->nw_dst_mask = src1->nw_dst_mask & src2->nw_dst_mask;
+}
+
+/* Returns a hash of the wildcards in 'wc'. */
+uint32_t
+flow_wildcards_hash(const struct flow_wildcards *wc)
+{
+ /* There is no need to include nw_src_mask or nw_dst_mask because they do
+ * not add any information (they can be computed from wc->wildcards). */
+ return hash_int(wc->wildcards, 0);
+}
+
+/* Returns true if 'a' and 'b' represent the same wildcards, false if they are
+ * different. */
+bool
+flow_wildcards_equal(const struct flow_wildcards *a,
+ const struct flow_wildcards *b)
+{
+ return a->wildcards == b->wildcards;
+}
+
+/* Returns true if at least one bit or field is wildcarded in 'a' but not in
+ * 'b', false otherwise. */
+bool
+flow_wildcards_has_extra(const struct flow_wildcards *a,
+ const struct flow_wildcards *b)
+{
+#define OFPFW_NW_MASK (OFPFW_NW_SRC_MASK | OFPFW_NW_DST_MASK)
+ return ((a->wildcards & ~(b->wildcards | OFPFW_NW_MASK))
+ || (a->nw_src_mask & b->nw_src_mask) != b->nw_src_mask
+ || (a->nw_dst_mask & b->nw_dst_mask) != b->nw_dst_mask);
+}
+
+static int
+count_ones(ovs_be32 mask)
+{
+#if __GNUC__ >= 4
+ return __builtin_popcount(mask);
+#else
+ int bits;
+
+ for (bits = 0; mask; bits++) {
+ mask &= mask - 1;
+ }
+
+ return bits;
+#endif
+}
+
+static bool
+set_nw_mask(struct flow_wildcards *wc, ovs_be32 mask,
+ ovs_be32 *maskp, int shift)
+{
+ int wcbits = 32 - count_ones(mask);
+ if (flow_nw_bits_to_mask(wcbits, 0) == mask) {
+ wc->wildcards &= ~(0x3f << shift);
+ wc->wildcards |= wcbits << shift;
+ *maskp = mask;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+/* Sets the IP (or ARP) source wildcard mask to CIDR 'mask' (consisting of N
+ * high-order 1-bit and 32-N low-order 0-bits). Returns true if successful,
+ * false if 'mask' is not a CIDR mask. */
+bool
+flow_wildcards_set_nw_src_mask(struct flow_wildcards *wc, ovs_be32 mask)
+{
+ return set_nw_mask(wc, mask, &wc->nw_src_mask, OFPFW_NW_SRC_SHIFT);
+}
+
+/* Sets the IP (or ARP) destination wildcard mask to CIDR 'mask' (consisting of
+ * N high-order 1-bit and 32-N low-order 0-bits). Returns true if successful,
+ * false if 'mask' is not a CIDR mask. */
+bool
+flow_wildcards_set_nw_dst_mask(struct flow_wildcards *wc, ovs_be32 mask)
+{
+ return set_nw_mask(wc, mask, &wc->nw_dst_mask, OFPFW_NW_DST_SHIFT);
+}