v4.19.13 snapshot.
diff --git a/include/net/mld.h b/include/net/mld.h
new file mode 100644
index 0000000..b0f5b31
--- /dev/null
+++ b/include/net/mld.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_MLD_H
+#define LINUX_MLD_H
+
+#include <linux/in6.h>
+#include <linux/icmpv6.h>
+
+/* MLDv1 Query/Report/Done */
+struct mld_msg {
+ struct icmp6hdr mld_hdr;
+ struct in6_addr mld_mca;
+};
+
+#define mld_type mld_hdr.icmp6_type
+#define mld_code mld_hdr.icmp6_code
+#define mld_cksum mld_hdr.icmp6_cksum
+#define mld_maxdelay mld_hdr.icmp6_maxdelay
+#define mld_reserved mld_hdr.icmp6_dataun.un_data16[1]
+
+/* Multicast Listener Discovery version 2 headers */
+/* MLDv2 Report */
+struct mld2_grec {
+ __u8 grec_type;
+ __u8 grec_auxwords;
+ __be16 grec_nsrcs;
+ struct in6_addr grec_mca;
+ struct in6_addr grec_src[0];
+};
+
+struct mld2_report {
+ struct icmp6hdr mld2r_hdr;
+ struct mld2_grec mld2r_grec[0];
+};
+
+#define mld2r_type mld2r_hdr.icmp6_type
+#define mld2r_resv1 mld2r_hdr.icmp6_code
+#define mld2r_cksum mld2r_hdr.icmp6_cksum
+#define mld2r_resv2 mld2r_hdr.icmp6_dataun.un_data16[0]
+#define mld2r_ngrec mld2r_hdr.icmp6_dataun.un_data16[1]
+
+/* MLDv2 Query */
+struct mld2_query {
+ struct icmp6hdr mld2q_hdr;
+ struct in6_addr mld2q_mca;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+ __u8 mld2q_qrv:3,
+ mld2q_suppress:1,
+ mld2q_resv2:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+ __u8 mld2q_resv2:4,
+ mld2q_suppress:1,
+ mld2q_qrv:3;
+#else
+#error "Please fix <asm/byteorder.h>"
+#endif
+ __u8 mld2q_qqic;
+ __be16 mld2q_nsrcs;
+ struct in6_addr mld2q_srcs[0];
+};
+
+#define mld2q_type mld2q_hdr.icmp6_type
+#define mld2q_code mld2q_hdr.icmp6_code
+#define mld2q_cksum mld2q_hdr.icmp6_cksum
+#define mld2q_mrc mld2q_hdr.icmp6_maxdelay
+#define mld2q_resv1 mld2q_hdr.icmp6_dataun.un_data16[1]
+
+/* RFC3810, 5.1.3. Maximum Response Code:
+ *
+ * If Maximum Response Code >= 32768, Maximum Response Code represents a
+ * floating-point value as follows:
+ *
+ * 0 1 2 3 4 5 6 7 8 9 A B C D E F
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |1| exp | mant |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+#define MLDV2_MRC_EXP(value) (((value) >> 12) & 0x0007)
+#define MLDV2_MRC_MAN(value) ((value) & 0x0fff)
+
+/* RFC3810, 5.1.9. QQIC (Querier's Query Interval Code):
+ *
+ * If QQIC >= 128, QQIC represents a floating-point value as follows:
+ *
+ * 0 1 2 3 4 5 6 7
+ * +-+-+-+-+-+-+-+-+
+ * |1| exp | mant |
+ * +-+-+-+-+-+-+-+-+
+ */
+#define MLDV2_QQIC_EXP(value) (((value) >> 4) & 0x07)
+#define MLDV2_QQIC_MAN(value) ((value) & 0x0f)
+
+#define MLD_EXP_MIN_LIMIT 32768UL
+#define MLDV1_MRD_MAX_COMPAT (MLD_EXP_MIN_LIMIT - 1)
+
+static inline unsigned long mldv2_mrc(const struct mld2_query *mlh2)
+{
+ /* RFC3810, 5.1.3. Maximum Response Code */
+ unsigned long ret, mc_mrc = ntohs(mlh2->mld2q_mrc);
+
+ if (mc_mrc < MLD_EXP_MIN_LIMIT) {
+ ret = mc_mrc;
+ } else {
+ unsigned long mc_man, mc_exp;
+
+ mc_exp = MLDV2_MRC_EXP(mc_mrc);
+ mc_man = MLDV2_MRC_MAN(mc_mrc);
+
+ ret = (mc_man | 0x1000) << (mc_exp + 3);
+ }
+
+ return ret;
+}
+
+#endif