xref: /openbmc/linux/include/net/mld.h (revision 9cfc5c90)
1 #ifndef LINUX_MLD_H
2 #define LINUX_MLD_H
3 
4 #include <linux/in6.h>
5 #include <linux/icmpv6.h>
6 
7 /* MLDv1 Query/Report/Done */
8 struct mld_msg {
9 	struct icmp6hdr		mld_hdr;
10 	struct in6_addr		mld_mca;
11 };
12 
13 #define mld_type		mld_hdr.icmp6_type
14 #define mld_code		mld_hdr.icmp6_code
15 #define mld_cksum		mld_hdr.icmp6_cksum
16 #define mld_maxdelay		mld_hdr.icmp6_maxdelay
17 #define mld_reserved		mld_hdr.icmp6_dataun.un_data16[1]
18 
19 /* Multicast Listener Discovery version 2 headers */
20 /* MLDv2 Report */
21 struct mld2_grec {
22 	__u8		grec_type;
23 	__u8		grec_auxwords;
24 	__be16		grec_nsrcs;
25 	struct in6_addr	grec_mca;
26 	struct in6_addr	grec_src[0];
27 };
28 
29 struct mld2_report {
30 	struct icmp6hdr		mld2r_hdr;
31 	struct mld2_grec	mld2r_grec[0];
32 };
33 
34 #define mld2r_type		mld2r_hdr.icmp6_type
35 #define mld2r_resv1		mld2r_hdr.icmp6_code
36 #define mld2r_cksum		mld2r_hdr.icmp6_cksum
37 #define mld2r_resv2		mld2r_hdr.icmp6_dataun.un_data16[0]
38 #define mld2r_ngrec		mld2r_hdr.icmp6_dataun.un_data16[1]
39 
40 /* MLDv2 Query */
41 struct mld2_query {
42 	struct icmp6hdr		mld2q_hdr;
43 	struct in6_addr		mld2q_mca;
44 #if defined(__LITTLE_ENDIAN_BITFIELD)
45 	__u8			mld2q_qrv:3,
46 				mld2q_suppress:1,
47 				mld2q_resv2:4;
48 #elif defined(__BIG_ENDIAN_BITFIELD)
49 	__u8			mld2q_resv2:4,
50 				mld2q_suppress:1,
51 				mld2q_qrv:3;
52 #else
53 #error "Please fix <asm/byteorder.h>"
54 #endif
55 	__u8			mld2q_qqic;
56 	__be16			mld2q_nsrcs;
57 	struct in6_addr		mld2q_srcs[0];
58 };
59 
60 #define mld2q_type		mld2q_hdr.icmp6_type
61 #define mld2q_code		mld2q_hdr.icmp6_code
62 #define mld2q_cksum		mld2q_hdr.icmp6_cksum
63 #define mld2q_mrc		mld2q_hdr.icmp6_maxdelay
64 #define mld2q_resv1		mld2q_hdr.icmp6_dataun.un_data16[1]
65 
66 /* RFC3810, 5.1.3. Maximum Response Code:
67  *
68  * If Maximum Response Code >= 32768, Maximum Response Code represents a
69  * floating-point value as follows:
70  *
71  *  0 1 2 3 4 5 6 7 8 9 A B C D E F
72  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
73  * |1| exp |          mant         |
74  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
75  */
76 #define MLDV2_MRC_EXP(value)	(((value) >> 12) & 0x0007)
77 #define MLDV2_MRC_MAN(value)	((value) & 0x0fff)
78 
79 /* RFC3810, 5.1.9. QQIC (Querier's Query Interval Code):
80  *
81  * If QQIC >= 128, QQIC represents a floating-point value as follows:
82  *
83  *  0 1 2 3 4 5 6 7
84  * +-+-+-+-+-+-+-+-+
85  * |1| exp | mant  |
86  * +-+-+-+-+-+-+-+-+
87  */
88 #define MLDV2_QQIC_EXP(value)	(((value) >> 4) & 0x07)
89 #define MLDV2_QQIC_MAN(value)	((value) & 0x0f)
90 
91 #define MLD_EXP_MIN_LIMIT	32768UL
92 #define MLDV1_MRD_MAX_COMPAT	(MLD_EXP_MIN_LIMIT - 1)
93 
94 static inline unsigned long mldv2_mrc(const struct mld2_query *mlh2)
95 {
96 	/* RFC3810, 5.1.3. Maximum Response Code */
97 	unsigned long ret, mc_mrc = ntohs(mlh2->mld2q_mrc);
98 
99 	if (mc_mrc < MLD_EXP_MIN_LIMIT) {
100 		ret = mc_mrc;
101 	} else {
102 		unsigned long mc_man, mc_exp;
103 
104 		mc_exp = MLDV2_MRC_EXP(mc_mrc);
105 		mc_man = MLDV2_MRC_MAN(mc_mrc);
106 
107 		ret = (mc_man | 0x1000) << (mc_exp + 3);
108 	}
109 
110 	return ret;
111 }
112 
113 #endif
114