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/*
* MLD protocol definitions
* Copyright (C) 2022 David Lamparter for NetDEF, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PIM6_MLD_PROTOCOL_H
#define _PIM6_MLD_PROTOCOL_H
#include <stdalign.h>
#include <stdint.h>
/* There is a struct icmp6_hdr provided by OS, but it includes 4 bytes of data.
* Not helpful for us if we want to put the MLD struct after it.
*/
struct icmp6_plain_hdr {
uint8_t icmp6_type;
uint8_t icmp6_code;
uint16_t icmp6_cksum;
};
static_assert(sizeof(struct icmp6_plain_hdr) == 4, "struct mismatch");
static_assert(alignof(struct icmp6_plain_hdr) <= 4, "struct mismatch");
/* for MLDv1 query, report and leave all use the same packet format */
struct mld_v1_pkt {
uint16_t max_resp_code;
uint16_t rsvd0;
struct in6_addr grp;
};
static_assert(sizeof(struct mld_v1_pkt) == 20, "struct mismatch");
static_assert(alignof(struct mld_v1_pkt) <= 4, "struct mismatch");
struct mld_v2_query_hdr {
uint16_t max_resp_code;
uint16_t rsvd0;
struct in6_addr grp;
uint8_t flags;
uint8_t qqic;
uint16_t n_src;
struct in6_addr srcs[0];
};
static_assert(sizeof(struct mld_v2_query_hdr) == 24, "struct mismatch");
static_assert(alignof(struct mld_v2_query_hdr) <= 4, "struct mismatch");
struct mld_v2_report_hdr {
uint16_t rsvd;
uint16_t n_records;
};
static_assert(sizeof(struct mld_v2_report_hdr) == 4, "struct mismatch");
static_assert(alignof(struct mld_v2_report_hdr) <= 4, "struct mismatch");
struct mld_v2_rec_hdr {
uint8_t type;
uint8_t aux_len;
uint16_t n_src;
struct in6_addr grp;
struct in6_addr srcs[0];
};
static_assert(sizeof(struct mld_v2_rec_hdr) == 20, "struct mismatch");
static_assert(alignof(struct mld_v2_rec_hdr) <= 4, "struct mismatch");
/* clang-format off */
enum icmp6_mld_type {
ICMP6_MLD_QUERY = 130,
ICMP6_MLD_V1_REPORT = 131,
ICMP6_MLD_V1_DONE = 132,
ICMP6_MLD_V2_REPORT = 143,
};
enum mld_v2_rec_type {
MLD_RECTYPE_IS_INCLUDE = 1,
MLD_RECTYPE_IS_EXCLUDE = 2,
MLD_RECTYPE_CHANGE_TO_INCLUDE = 3,
MLD_RECTYPE_CHANGE_TO_EXCLUDE = 4,
MLD_RECTYPE_ALLOW_NEW_SOURCES = 5,
MLD_RECTYPE_BLOCK_OLD_SOURCES = 6,
};
/* clang-format on */
/* helper functions */
static inline unsigned int mld_max_resp_decode(uint16_t wire)
{
uint16_t code = ntohs(wire);
uint8_t exp;
if (code < 0x8000)
return code;
exp = (code >> 12) & 0x7;
return ((code & 0xfff) | 0x1000) << (exp + 3);
}
static inline uint16_t mld_max_resp_encode(uint32_t value)
{
uint16_t code;
uint8_t exp;
if (value < 0x8000)
code = value;
else {
exp = 16 - __builtin_clz(value);
code = (value >> (exp + 3)) & 0xfff;
code |= 0x8000 | (exp << 12);
}
return htons(code);
}
#endif /* _PIM6_MLD_PROTOCOL_H */
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