root/include/net/mld.h

INCLUDED FROM

DEFINITIONS

1. mldv2_mrc

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef LINUX_MLD_H
   3 #define LINUX_MLD_H
   4 
   5 #include <linux/in6.h>
   6 #include <linux/icmpv6.h>
   7 
   8 /* MLDv1 Query/Report/Done */
   9 struct mld_msg {
  10         struct icmp6hdr         mld_hdr;
  11         struct in6_addr         mld_mca;
  12 };
  13 
  14 #define mld_type                mld_hdr.icmp6_type
  15 #define mld_code                mld_hdr.icmp6_code
  16 #define mld_cksum               mld_hdr.icmp6_cksum
  17 #define mld_maxdelay            mld_hdr.icmp6_maxdelay
  18 #define mld_reserved            mld_hdr.icmp6_dataun.un_data16[1]
  19 
  20 /* Multicast Listener Discovery version 2 headers */
  21 /* MLDv2 Report */
  22 struct mld2_grec {
  23         __u8            grec_type;
  24         __u8            grec_auxwords;
  25         __be16          grec_nsrcs;
  26         struct in6_addr grec_mca;
  27         struct in6_addr grec_src[0];
  28 };
  29 
  30 struct mld2_report {
  31         struct icmp6hdr         mld2r_hdr;
  32         struct mld2_grec        mld2r_grec[0];
  33 };
  34 
  35 #define mld2r_type              mld2r_hdr.icmp6_type
  36 #define mld2r_resv1             mld2r_hdr.icmp6_code
  37 #define mld2r_cksum             mld2r_hdr.icmp6_cksum
  38 #define mld2r_resv2             mld2r_hdr.icmp6_dataun.un_data16[0]
  39 #define mld2r_ngrec             mld2r_hdr.icmp6_dataun.un_data16[1]
  40 
  41 /* MLDv2 Query */
  42 struct mld2_query {
  43         struct icmp6hdr         mld2q_hdr;
  44         struct in6_addr         mld2q_mca;
  45 #if defined(__LITTLE_ENDIAN_BITFIELD)
  46         __u8                    mld2q_qrv:3,
  47                                 mld2q_suppress:1,
  48                                 mld2q_resv2:4;
  49 #elif defined(__BIG_ENDIAN_BITFIELD)
  50         __u8                    mld2q_resv2:4,
  51                                 mld2q_suppress:1,
  52                                 mld2q_qrv:3;
  53 #else
  54 #error "Please fix <asm/byteorder.h>"
  55 #endif
  56         __u8                    mld2q_qqic;
  57         __be16                  mld2q_nsrcs;
  58         struct in6_addr         mld2q_srcs[0];
  59 };
  60 
  61 #define mld2q_type              mld2q_hdr.icmp6_type
  62 #define mld2q_code              mld2q_hdr.icmp6_code
  63 #define mld2q_cksum             mld2q_hdr.icmp6_cksum
  64 #define mld2q_mrc               mld2q_hdr.icmp6_maxdelay
  65 #define mld2q_resv1             mld2q_hdr.icmp6_dataun.un_data16[1]
  66 
  67 /* RFC3810, 5.1.3. Maximum Response Code:
  68  *
  69  * If Maximum Response Code >= 32768, Maximum Response Code represents a
  70  * floating-point value as follows:
  71  *
  72  *  0 1 2 3 4 5 6 7 8 9 A B C D E F
  73  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  74  * |1| exp |          mant         |
  75  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  76  */
  77 #define MLDV2_MRC_EXP(value)    (((value) >> 12) & 0x0007)
  78 #define MLDV2_MRC_MAN(value)    ((value) & 0x0fff)
  79 
  80 /* RFC3810, 5.1.9. QQIC (Querier's Query Interval Code):
  81  *
  82  * If QQIC >= 128, QQIC represents a floating-point value as follows:
  83  *
  84  *  0 1 2 3 4 5 6 7
  85  * +-+-+-+-+-+-+-+-+
  86  * |1| exp | mant  |
  87  * +-+-+-+-+-+-+-+-+
  88  */
  89 #define MLDV2_QQIC_EXP(value)   (((value) >> 4) & 0x07)
  90 #define MLDV2_QQIC_MAN(value)   ((value) & 0x0f)
  91 
  92 #define MLD_EXP_MIN_LIMIT       32768UL
  93 #define MLDV1_MRD_MAX_COMPAT    (MLD_EXP_MIN_LIMIT - 1)
  94 
  95 static inline unsigned long mldv2_mrc(const struct mld2_query *mlh2)
  96 {
  97         /* RFC3810, 5.1.3. Maximum Response Code */
  98         unsigned long ret, mc_mrc = ntohs(mlh2->mld2q_mrc);
  99 
 100         if (mc_mrc < MLD_EXP_MIN_LIMIT) {
 101                 ret = mc_mrc;
 102         } else {
 103                 unsigned long mc_man, mc_exp;
 104 
 105                 mc_exp = MLDV2_MRC_EXP(mc_mrc);
 106                 mc_man = MLDV2_MRC_MAN(mc_mrc);
 107 
 108                 ret = (mc_man | 0x1000) << (mc_exp + 3);
 109         }
 110 
 111         return ret;
 112 }
 113 
 114 #endif