diff options
| -rw-r--r-- | pkg/tcpip/header/igmp.go | 17 | ||||
| -rw-r--r-- | pkg/tcpip/network/ipv4/igmp.go | 40 |
2 files changed, 33 insertions, 24 deletions
diff --git a/pkg/tcpip/header/igmp.go b/pkg/tcpip/header/igmp.go index e0f5d46f4..5c5be1b9d 100644 --- a/pkg/tcpip/header/igmp.go +++ b/pkg/tcpip/header/igmp.go @@ -17,6 +17,7 @@ package header import ( "encoding/binary" "fmt" + "time" "gvisor.dev/gvisor/pkg/tcpip" ) @@ -103,7 +104,15 @@ func (b IGMP) SetType(t IGMPType) { b[igmpTypeOffset] = byte(t) } // MaxRespTime gets the MaxRespTimeField. This is meaningful only in Membership // Query messages, in other cases it is set to 0 by the sender and ignored by // the receiver. -func (b IGMP) MaxRespTime() byte { return b[igmpMaxRespTimeOffset] } +func (b IGMP) MaxRespTime() time.Duration { + // As per RFC 2236 section 2.2, + // + // The Max Response Time field is meaningful only in Membership Query + // messages, and specifies the maximum allowed time before sending a + // responding report in units of 1/10 second. In all other messages, it + // is set to zero by the sender and ignored by receivers. + return DecisecondToDuration(b[igmpMaxRespTimeOffset]) +} // SetMaxRespTime sets the MaxRespTimeField. func (b IGMP) SetMaxRespTime(m byte) { b[igmpMaxRespTimeOffset] = m } @@ -164,3 +173,9 @@ func IGMPCalculateChecksum(h IGMP) uint16 { h.SetChecksum(existingXsum) return xsum } + +// DecisecondToDuration converts a value representing deci-seconds to a +// time.Duration. +func DecisecondToDuration(ds uint8) time.Duration { + return time.Duration(ds) * time.Second / 10 +} diff --git a/pkg/tcpip/network/ipv4/igmp.go b/pkg/tcpip/network/ipv4/igmp.go index e1de58f73..18fe2fd2f 100644 --- a/pkg/tcpip/network/ipv4/igmp.go +++ b/pkg/tcpip/network/ipv4/igmp.go @@ -35,15 +35,18 @@ const ( // See note on igmpState.igmpV1Present for more detail. v1RouterPresentTimeout = 400 * time.Second - // v1MaxRespTimeTenthSec from RFC 2236 Section 4, Page 5. "The IGMPv1 router + // v1MaxRespTime from RFC 2236 Section 4, Page 5. "The IGMPv1 router // will send General Queries with the Max Response Time set to 0. This MUST // be interpreted as a value of 100 (10 seconds)." - v1MaxRespTimeTenthSec = 100 - - // UnsolicitedReportIntervalMaxTenthSec from RFC 2236 Section 8.10, Page 19. - // As all IGMP delay timers are set to a random value between 0 and the - // interval, this is technically a maximum. - UnsolicitedReportIntervalMaxTenthSec = 100 + // + // Note that the Max Response Time field is a value in units of deciseconds. + v1MaxRespTime = 10 * time.Second + + // UnsolicitedReportIntervalMax is the maximum delay between sending + // unsolicited IGMP reports. + // + // Obtained from RFC 2236 Section 8.10, Page 19. + UnsolicitedReportIntervalMax = 10 * time.Second ) // igmpState is the per-interface IGMP state. @@ -185,7 +188,7 @@ func (igmp *igmpState) handleIGMP(pkt *stack.PacketBuffer) { } } -func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxRespTime byte) { +func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxRespTime time.Duration) { igmp.mu.Lock() defer igmp.mu.Unlock() @@ -196,7 +199,7 @@ func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxResp igmp.mu.igmpV1Job.Cancel() igmp.mu.igmpV1Job.Schedule(v1RouterPresentTimeout) igmp.mu.igmpV1Present = true - maxRespTime = v1MaxRespTimeTenthSec + maxRespTime = v1MaxRespTime } // IPv4Any is the General Query Address. @@ -215,7 +218,7 @@ func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxResp // modify IGMP state directly. // // Precondition: igmp.mu MUST be read locked. -func (igmp *igmpState) setDelayTimerForAddressRLocked(groupAddress tcpip.Address, info *membershipInfo, maxRespTime byte) { +func (igmp *igmpState) setDelayTimerForAddressRLocked(groupAddress tcpip.Address, info *membershipInfo, maxRespTime time.Duration) { if info.state == delayingMember { // As per RFC 2236 Section 3, page 3: "If a timer for the group is already // running, it is reset to the random value only if the requested Max @@ -352,7 +355,7 @@ func (igmp *igmpState) joinGroup(groupAddress tcpip.Address) *tcpip.Error { // it should immediately transmit an unsolicited Version 2 Membership Report // for that group" ... "it is recommended that it be repeated" igmp.sendReportLocked(groupAddress) - igmp.setDelayTimerForAddressRLocked(groupAddress, &info, UnsolicitedReportIntervalMaxTenthSec) + igmp.setDelayTimerForAddressRLocked(groupAddress, &info, UnsolicitedReportIntervalMax) igmp.mu.memberships[groupAddress] = info return nil @@ -383,16 +386,7 @@ func (igmp *igmpState) leaveGroup(groupAddress tcpip.Address) { } // RFC 2236 Section 3, Page 3: The response time is set to a "random value... -// selected from the range (0, Max Response Time]" where Max Resp Time is given -// in units of 1/10 of a second. -func (igmp *igmpState) calculateDelayTimerDuration(maxRespTime byte) time.Duration { - maxRespTimeDuration := DecisecondToSecond(maxRespTime) - return time.Duration(igmp.ep.protocol.stack.Rand().Int63n(int64(maxRespTimeDuration))) -} - -// DecisecondToSecond converts a byte representing deci-seconds to a Duration -// type. This helper function exists because the IGMP stack sends and receives -// Max Response Times in deci-seconds. -func DecisecondToSecond(ds byte) time.Duration { - return time.Duration(ds) * time.Second / 10 +// selected from the range (0, Max Response Time]". +func (igmp *igmpState) calculateDelayTimerDuration(maxRespTime time.Duration) time.Duration { + return time.Duration(igmp.ep.protocol.stack.Rand().Int63n(int64(maxRespTime))) } |