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	Fresh ground-up MLD implementation with subscriber-tracking for MLDv2. Intended to be adapted for IPv4 and replace the IGMP implementation at a later point. Tested in ANVL, currently at 94/116. Some issues/TODOs are left in the code as CPP_NOTICE markers, but the code is very much good enough to proceed since otherwise we're blocked on overall PIM v6 progress. Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
		
			
				
	
	
		
			126 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			126 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * MLD protocol definitions
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 * Copyright (C) 2022  David Lamparter for NetDEF, Inc.
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 *
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 * This program is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License as published by the Free
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 * Software Foundation; either version 2 of the License, or (at your option)
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 * any later version.
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 *
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 * This program is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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 * more details.
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 *
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 * You should have received a copy of the GNU General Public License along
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 * with this program; see the file COPYING; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#ifndef _PIM6_MLD_PROTOCOL_H
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#define _PIM6_MLD_PROTOCOL_H
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#include <stdalign.h>
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#include <stdint.h>
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/* There is a struct icmp6_hdr provided by OS, but it includes 4 bytes of data.
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 * Not helpful for us if we want to put the MLD struct after it.
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 */
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struct icmp6_plain_hdr {
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	uint8_t icmp6_type;
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	uint8_t icmp6_code;
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	uint16_t icmp6_cksum;
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};
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static_assert(sizeof(struct icmp6_plain_hdr) == 4, "struct mismatch");
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static_assert(alignof(struct icmp6_plain_hdr) <= 4, "struct mismatch");
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/* for MLDv1 query, report and leave all use the same packet format */
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struct mld_v1_pkt {
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	uint16_t max_resp_code;
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	uint16_t rsvd0;
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	struct in6_addr grp;
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};
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static_assert(sizeof(struct mld_v1_pkt) == 20, "struct mismatch");
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static_assert(alignof(struct mld_v1_pkt) <= 4, "struct mismatch");
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struct mld_v2_query_hdr {
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	uint16_t max_resp_code;
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	uint16_t rsvd0;
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	struct in6_addr grp;
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	uint8_t flags;
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	uint8_t qqic;
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	uint16_t n_src;
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	struct in6_addr srcs[0];
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};
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static_assert(sizeof(struct mld_v2_query_hdr) == 24, "struct mismatch");
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static_assert(alignof(struct mld_v2_query_hdr) <= 4, "struct mismatch");
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struct mld_v2_report_hdr {
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	uint16_t rsvd;
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	uint16_t n_records;
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};
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static_assert(sizeof(struct mld_v2_report_hdr) == 4, "struct mismatch");
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static_assert(alignof(struct mld_v2_report_hdr) <= 4, "struct mismatch");
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struct mld_v2_rec_hdr {
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	uint8_t type;
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	uint8_t aux_len;
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	uint16_t n_src;
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	struct in6_addr grp;
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	struct in6_addr srcs[0];
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};
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static_assert(sizeof(struct mld_v2_rec_hdr) == 20, "struct mismatch");
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static_assert(alignof(struct mld_v2_rec_hdr) <= 4, "struct mismatch");
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/* clang-format off */
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enum icmp6_mld_type {
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	ICMP6_MLD_QUERY			= 130,
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	ICMP6_MLD_V1_REPORT		= 131,
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	ICMP6_MLD_V1_DONE		= 132,
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	ICMP6_MLD_V2_REPORT		= 143,
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};
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enum mld_v2_rec_type {
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	MLD_RECTYPE_IS_INCLUDE		= 1,
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	MLD_RECTYPE_IS_EXCLUDE		= 2,
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	MLD_RECTYPE_CHANGE_TO_INCLUDE	= 3,
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	MLD_RECTYPE_CHANGE_TO_EXCLUDE	= 4,
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	MLD_RECTYPE_ALLOW_NEW_SOURCES	= 5,
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	MLD_RECTYPE_BLOCK_OLD_SOURCES	= 6,
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};
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/* clang-format on */
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/* helper functions */
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static inline unsigned int mld_max_resp_decode(uint16_t wire)
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{
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	uint16_t code = ntohs(wire);
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	uint8_t exp;
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	if (code < 0x8000)
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		return code;
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	exp = (code >> 12) & 0x7;
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	return ((code & 0xfff) | 0x1000) << (exp + 3);
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}
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static inline uint16_t mld_max_resp_encode(uint32_t value)
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{
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	uint16_t code;
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	uint8_t exp;
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	if (value < 0x8000)
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		code = value;
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	else {
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		exp = 16 - __builtin_clz(value);
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		code = (value >> (exp + 3)) & 0xfff;
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		code |= 0x8000 | (exp << 12);
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	}
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	return htons(code);
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}
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#endif /* _PIM6_MLD_PROTOCOL_H */
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