Get rid of the IGMPV3_MRC macro and use the igmpv3_mrt() API to calculate the Max Resp Time from the Maximum Response Code.
Similarly, for IGMPV3_QQIC, use the igmpv3_qqi() API to calculate the Querier's Query Interval from the QQIC field. Signed-off-by: Ujjal Roy <[email protected]> --- include/linux/igmp.h | 78 +++++++++++++++++++++++++++++++++++---- net/bridge/br_multicast.c | 2 +- net/ipv4/igmp.c | 6 +-- 3 files changed, 74 insertions(+), 12 deletions(-) diff --git a/include/linux/igmp.h b/include/linux/igmp.h index 073b30a9b850..3c12c0a63492 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -92,15 +92,77 @@ struct ip_mc_list { struct rcu_head rcu; }; +/* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 4.1.7. QQIC (Querier's Query Interval Code) + * + * If Max Resp Code >= 128, Max Resp Code represents a floating-point + * value as follows: + * If QQIC >= 128, QQIC represents a floating-point value as follows: + * + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+ + */ +#define IGMPV3_FP_EXP(value) (((value) >> 4) & 0x07) +#define IGMPV3_FP_MAN(value) ((value) & 0x0f) + +/* IGMPV3 floating-point exponential field threshold */ +#define IGMPV3_EXP_MIN_THRESHOLD 128 + /* V3 exponential field decoding */ -#define IGMPV3_MASK(value, nb) ((nb)>=32 ? (value) : ((1<<(nb))-1) & (value)) -#define IGMPV3_EXP(thresh, nbmant, nbexp, value) \ - ((value) < (thresh) ? (value) : \ - ((IGMPV3_MASK(value, nbmant) | (1<<(nbmant))) << \ - (IGMPV3_MASK((value) >> (nbmant), nbexp) + (nbexp)))) - -#define IGMPV3_QQIC(value) IGMPV3_EXP(0x80, 4, 3, value) -#define IGMPV3_MRC(value) IGMPV3_EXP(0x80, 4, 3, value) + +/* + * IGMPv3 QQI/MRT 8-bit exponential field decode. + * + * RFC3376, 4.1.1 & 4.1.7. defines the decoding formula: + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+ + * Max Resp Time = (mant | 0x10) << (exp + 3) + * QQI = (mant | 0x10) << (exp + 3) + */ +static inline unsigned long igmpv3_exp_field_decode(const u8 code) +{ + /* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 4.1.7. QQIC (Querier's Query Interval Code) + */ + if (code < IGMPV3_EXP_MIN_THRESHOLD) { + return (unsigned long)code; + } else { + unsigned long mc_man, mc_exp; + + mc_exp = IGMPV3_FP_EXP(code); + mc_man = IGMPV3_FP_MAN(code); + + return ((mc_man | 0x10) << (mc_exp + 3)); + } +} + +/* Calculate Max Resp Time from Maximum Response Code */ +static inline unsigned long igmpv3_mrt(const struct igmpv3_query *ih3) +{ + /* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 8.3. Query Response Interval + */ + return igmpv3_exp_field_decode(ih3->code); +} + +/* Calculate Querier's Query Interval from Querier's Query Interval Code */ +static inline unsigned long igmpv3_qqi(const struct igmpv3_query *ih3) +{ + /* RFC3376, relevant sections: + * - 4.1.7. QQIC (Querier's Query Interval Code) + * - 8.2. Query Interval + * - 8.12. Older Version Querier Present Timeout + * (the [Query Interval] in the last Query received) + */ + return igmpv3_exp_field_decode(ih3->qqic); +} static inline int ip_mc_may_pull(struct sk_buff *skb, unsigned int len) { diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 881d866d687a..9fec76e887bc 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -3518,7 +3518,7 @@ static void br_ip4_multicast_query(struct net_bridge_mcast *brmctx, goto out; max_delay = ih3->code ? - IGMPV3_MRC(ih3->code) * (HZ / IGMP_TIMER_SCALE) : 1; + igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE) : 1; } else { goto out; } diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index a674fb44ec25..8c6102737096 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -991,7 +991,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, * different encoding. We use the v3 encoding as more likely * to be intended in a v3 query. */ - max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); + max_delay = igmpv3_mrt(ih3)*(HZ/IGMP_TIMER_SCALE); if (!max_delay) max_delay = 1; /* can't mod w/ 0 */ } else { /* v3 */ @@ -1006,7 +1006,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, ih3 = igmpv3_query_hdr(skb); } - max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); + max_delay = igmpv3_mrt(ih3)*(HZ/IGMP_TIMER_SCALE); if (!max_delay) max_delay = 1; /* can't mod w/ 0 */ WRITE_ONCE(in_dev->mr_maxdelay, max_delay); @@ -1016,7 +1016,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, * configured value. */ in_dev->mr_qrv = ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv); - in_dev->mr_qi = IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL; + in_dev->mr_qi = igmpv3_qqi(ih3)*HZ ?: IGMP_QUERY_INTERVAL; /* RFC3376, 8.3. Query Response Interval: * The number of seconds represented by the [Query Response -- 2.43.0
