Description:
This series addresses a mismatch in how multicast query
intervals and response codes are handled across IPv4 (IGMPv3)
and IPv6 (MLDv2). While decoding logic currently exists,
the corresponding encoding logic is missing during query
packet generation. This leads to incorrect intervals being
transmitted when values exceed their linear thresholds.
The patches introduce a unified floating-point encoding
approach based on RFC3376 and RFC3810, ensuring that large
intervals are correctly represented in QQIC and MRC fields
using the exponent-mantissa format.
Key Changes:
* ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify calculation
Removes legacy macros in favor of a cleaner, unified
calculation for retrieving intervals from encoded fields,
improving code maintainability.
* ipv6: mld: rename mldv2_mrc() and add mldv2_qqi()
Standardizes MLDv2 terminology by renaming mldv2_mrc()
to mldv2_mrd() (Maximum Response Delay) and introducing
a new API mldv2_qqi for QQI calculation, improving code
readability.
* ipv4: igmp: encode multicast exponential fields
Introduces the logic to dynamically calculate the exponent
and mantissa using bit-scan (fls). This ensures QQIC and
MRC fields (8-bit) are properly encoded when transmitting
query packets with intervals that exceed their respective
linear threshold value of 128 (for QQI/MRT).
* ipv6: mld: encode multicast exponential fields
Applies similar encoding logic for MLDv2. This ensures
QQIC (8-bit) and MRC (16-bit) fields are properly encoded
when transmitting query packets with intervals that exceed
their respective linear thresholds (128 for QQI; 32768
for MRD).
Impact:
These changes ensure that multicast queriers and listeners
stay synchronized on timing intervals, preventing protocol
timeouts or premature group membership expiration caused
by incorrectly formatted packet headers.
Ujjal Roy (4):
ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify calculation
ipv6: mld: rename mldv2_mrc() and add mldv2_qqi()
ipv4: igmp: encode multicast exponential fields
ipv6: mld: encode multicast exponential fields
include/linux/igmp.h | 158 +++++++++++++++++++++++++++++++--
include/net/mld.h | 179 ++++++++++++++++++++++++++++++++++++--
net/bridge/br_multicast.c | 22 +++--
net/ipv4/igmp.c | 6 +-
net/ipv6/mcast.c | 19 +---
5 files changed, 336 insertions(+), 48 deletions(-)
--
2.43.0
