linux/include/linux/pim.h

/* 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 …
#define PIM_V1_REGISTER …

/* Message types - V2 */
#define PIM_VERSION …

/* 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 { … };

#define PIM_NULL_REGISTER …

/* 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 { … };

/* PIMv2 register message header layout (ietf-draft-idmr-pimvsm-v2-00.ps */
struct pimreghdr { … };

int pim_rcv_v1(struct sk_buff *skb);

static inline bool ipmr_pimsm_enabled(void)
{ … }

static inline struct pimhdr *pim_hdr(const struct sk_buff *skb)
{ … }

static inline u8 pim_hdr_version(const struct pimhdr *pimhdr)
{ … }

static inline u8 pim_hdr_type(const struct pimhdr *pimhdr)
{ … }

/* check if the address is 224.0.0.13, RFC7761 sec 4.3.1 */
static inline bool pim_ipv4_all_pim_routers(__be32 addr)
{ … }
#endif