v4.19.13 snapshot.
diff --git a/include/linux/pim.h b/include/linux/pim.h
new file mode 100644
index 0000000..290d4d2
--- /dev/null
+++ b/include/linux/pim.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_PIM_H
+#define __LINUX_PIM_H
+
+#include <linux/skbuff.h>
+#include <asm/byteorder.h>
+
+/* Message types - V1 */
+#define PIM_V1_VERSION cpu_to_be32(0x10000000)
+#define PIM_V1_REGISTER 1
+
+/* Message types - V2 */
+#define PIM_VERSION 2
+
+/* RFC7761, sec 4.9:
+ * Type
+ * Types for specific PIM messages. PIM Types are:
+ *
+ * Message Type Destination
+ * ---------------------------------------------------------------------
+ * 0 = Hello Multicast to ALL-PIM-ROUTERS
+ * 1 = Register Unicast to RP
+ * 2 = Register-Stop Unicast to source of Register
+ * packet
+ * 3 = Join/Prune Multicast to ALL-PIM-ROUTERS
+ * 4 = Bootstrap Multicast to ALL-PIM-ROUTERS
+ * 5 = Assert Multicast to ALL-PIM-ROUTERS
+ * 6 = Graft (used in PIM-DM only) Unicast to RPF'(S)
+ * 7 = Graft-Ack (used in PIM-DM only) Unicast to source of Graft
+ * packet
+ * 8 = Candidate-RP-Advertisement Unicast to Domain's BSR
+ */
+enum {
+ PIM_TYPE_HELLO,
+ PIM_TYPE_REGISTER,
+ PIM_TYPE_REGISTER_STOP,
+ PIM_TYPE_JOIN_PRUNE,
+ PIM_TYPE_BOOTSTRAP,
+ PIM_TYPE_ASSERT,
+ PIM_TYPE_GRAFT,
+ PIM_TYPE_GRAFT_ACK,
+ PIM_TYPE_CANDIDATE_RP_ADV
+};
+
+#define PIM_NULL_REGISTER cpu_to_be32(0x40000000)
+
+/* RFC7761, sec 4.9:
+ * The PIM header common to all PIM messages is:
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |PIM Ver| Type | Reserved | Checksum |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct pimhdr {
+ __u8 type;
+ __u8 reserved;
+ __be16 csum;
+};
+
+/* PIMv2 register message header layout (ietf-draft-idmr-pimvsm-v2-00.ps */
+struct pimreghdr {
+ __u8 type;
+ __u8 reserved;
+ __be16 csum;
+ __be32 flags;
+};
+
+int pim_rcv_v1(struct sk_buff *skb);
+
+static inline bool ipmr_pimsm_enabled(void)
+{
+ return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
+}
+
+static inline struct pimhdr *pim_hdr(const struct sk_buff *skb)
+{
+ return (struct pimhdr *)skb_transport_header(skb);
+}
+
+static inline u8 pim_hdr_version(const struct pimhdr *pimhdr)
+{
+ return pimhdr->type >> 4;
+}
+
+static inline u8 pim_hdr_type(const struct pimhdr *pimhdr)
+{
+ return pimhdr->type & 0xf;
+}
+
+/* check if the address is 224.0.0.13, RFC7761 sec 4.3.1 */
+static inline bool pim_ipv4_all_pim_routers(__be32 addr)
+{
+ return addr == htonl(0xE000000D);
+}
+#endif