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* TCP reuses t_rxtshift to determine the backoff timer used for both thejhb2011-04-291-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | persist state and the retransmit timer. However, the code that implements "bad retransmit recovery" only checks t_rxtshift to see if an ACK has been received in during the first retransmit timeout window. As a result, if ticks has wrapped over to a negative value and a socket is in the persist state, it can incorrectly treat an ACK from the remote peer as a "bad retransmit recovery" and restore saved values such as snd_ssthresh and snd_cwnd. However, if the socket has never had a retransmit timeout, then these saved values will be zero, so snd_ssthresh and snd_cwnd will be set to 0. If the socket is in fast recovery (this can be caused by excessive duplicate ACKs such as those fixed by 220794), then each ACK that arrives triggers either NewReno or SACK partial ACK handling which clamps snd_cwnd to be no larger than snd_ssthresh. In effect, the socket's send window is permamently stuck at 0 even though the remote peer is advertising a much larger window and pending data is only sent via TCP window probes (so one byte every few seconds). Fix this by adding a new TCP pcb flag (TF_PREVVALID) that indicates that the various snd_*_prev fields in the pcb are valid and only perform "bad retransmit recovery" if this flag is set in the pcb. The flag is set on the first retransmit timeout that occurs and is cleared on subsequent retransmit timeouts or when entering the persist state. Reviewed by: bz MFC after: 2 weeks
* Trim extra spaces before tabs.jhb2011-01-071-9/+9
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* Fix a typo in a comment.jhb2010-12-211-1/+1
| | | | MFC after: 1 week
* Pass NULL instead of 0 for the th pointer value. NULL != 0 on all platforms.lstewart2010-12-021-1/+1
| | | | | | Submitted by: David Hayes <dahayes at swin edu au> MFC after: 9 weeks X-MFC with: r215166
* This commit marks the first formal contribution of the "Five New TCP Congestionlstewart2010-11-121-38/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Control Algorithms for FreeBSD" FreeBSD Foundation funded project. More details about the project are available at: http://caia.swin.edu.au/freebsd/5cc/ - Add a KPI and supporting infrastructure to allow modular congestion control algorithms to be used in the net stack. Algorithms can maintain per-connection state if required, and connections maintain their own algorithm pointer, which allows different connections to concurrently use different algorithms. The TCP_CONGESTION socket option can be used with getsockopt()/setsockopt() to programmatically query or change the congestion control algorithm respectively from within an application at runtime. - Integrate the framework with the TCP stack in as least intrusive a manner as possible. Care was also taken to develop the framework in a way that should allow integration with other congestion aware transport protocols (e.g. SCTP) in the future. The hope is that we will one day be able to share a single set of congestion control algorithm modules between all congestion aware transport protocols. - Introduce a new congestion recovery (TF_CONGRECOVERY) state into the TCP stack and use it to decouple the meaning of recovery from a congestion event and recovery from packet loss (TF_FASTRECOVERY) a la RFC2581. ECN and delay based congestion control protocols don't generally need to recover from packet loss and need a different way to note a congestion recovery episode within the stack. - Remove the net.inet.tcp.newreno sysctl, which simplifies some portions of code and ensures the stack always uses the appropriate mechanisms for recovering from packet loss during a congestion recovery episode. - Extract the NewReno congestion control algorithm from the TCP stack and massage it into module form. NewReno is always built into the kernel and will remain the default algorithm for the forseeable future. Implementations of additional different algorithms will become available in the near future. - Bump __FreeBSD_version to 900025 and note in UPDATING that rebuilding code that relies on the size of "struct tcpcb" is required. Many thanks go to the Cisco University Research Program Fund at Community Foundation Silicon Valley and the FreeBSD Foundation. Their support of our work at the Centre for Advanced Internet Architectures, Swinburne University of Technology is greatly appreciated. In collaboration with: David Hayes <dahayes at swin edu au> and Grenville Armitage <garmitage at swin edu au> Sponsored by: Cisco URP, FreeBSD Foundation Reviewed by: rpaulo Tested by: David Hayes (and many others over the years) MFC after: 3 months
* - spread tcp timer callout load evenly across cpus if ↵kmacy2010-03-201-10/+30
| | | | | | | | net.inet.tcp.per_cpu_timers is set to 1 - don't default to acquiring tcbinfo lock exclusively in rexmt MFC after: 7 days
* Locking the tcbinfo structure should not be necessary in tcp_timer_delack(),rwatson2010-03-071-3/+0
| | | | | | | | so don't. MFC after: 1 week Reviewed by: bz Sponsored by: Juniper Networks
* Add the ability to see TCP timers via netstat -x. This can be a usefulsilby2009-09-161-0/+21
| | | | | | | | | feature when you have a seemingly stuck socket and want to figure out why it has not been closed yet. No plans to MFC this, as it changes the netstat sysctl ABI. Reviewed by: andre, rwatson, Eric Van Gyzen
* Merge the remainder of kern_vimage.c and vimage.h into vnet.c andrwatson2009-08-011-1/+1
| | | | | | | | | | vnet.h, we now use jails (rather than vimages) as the abstraction for virtualization management, and what remained was specific to virtual network stacks. Minor cleanups are done in the process, and comments updated to reflect these changes. Reviewed by: bz Approved by: re (vimage blanket)
* Reimplement and/or implement vnet list locking by replacing a mostlyrwatson2009-07-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | unused custom mutex/condvar-based sleep locks with two locks: an rwlock (for non-sleeping use) and sxlock (for sleeping use). Either acquired for read is sufficient to stabilize the vnet list, but both must be acquired for write to modify the list. Replace previous no-op read locking macros, used in various places in the stack, with actual locking to prevent race conditions. Callers must declare when they may perform unbounded sleeps or not when selecting how to lock. Refactor vnet sysinits so that the vnet list and locks are initialized before kernel modules are linked, as the kernel linker will use them for modules loaded by the boot loader. Update various consumers of these KPIs based on whether they may sleep or not. Reviewed by: bz Approved by: re (kib)
* Build on Jeff Roberson's linker-set based dynamic per-CPU allocatorrwatson2009-07-141-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (DPCPU), as suggested by Peter Wemm, and implement a new per-virtual network stack memory allocator. Modify vnet to use the allocator instead of monolithic global container structures (vinet, ...). This change solves many binary compatibility problems associated with VIMAGE, and restores ELF symbols for virtualized global variables. Each virtualized global variable exists as a "reference copy", and also once per virtual network stack. Virtualized global variables are tagged at compile-time, placing the in a special linker set, which is loaded into a contiguous region of kernel memory. Virtualized global variables in the base kernel are linked as normal, but those in modules are copied and relocated to a reserved portion of the kernel's vnet region with the help of a the kernel linker. Virtualized global variables exist in per-vnet memory set up when the network stack instance is created, and are initialized statically from the reference copy. Run-time access occurs via an accessor macro, which converts from the current vnet and requested symbol to a per-vnet address. When "options VIMAGE" is not compiled into the kernel, normal global ELF symbols will be used instead and indirection is avoided. This change restores static initialization for network stack global variables, restores support for non-global symbols and types, eliminates the need for many subsystem constructors, eliminates large per-subsystem structures that caused many binary compatibility issues both for monitoring applications (netstat) and kernel modules, removes the per-function INIT_VNET_*() macros throughout the stack, eliminates the need for vnet_symmap ksym(2) munging, and eliminates duplicate definitions of virtualized globals under VIMAGE_GLOBALS. Bump __FreeBSD_version and update UPDATING. Portions submitted by: bz Reviewed by: bz, zec Discussed with: gnn, jamie, jeff, jhb, julian, sam Suggested by: peter Approved by: re (kensmith)
* Trim extra sets of ()'s.jhb2009-06-161-4/+4
| | | | Requested by: bde
* Update stats in struct tcpstat using two new macros, TCPSTAT_ADD() andrwatson2009-04-111-9/+9
| | | | | | | | TCPSTAT_INC(), rather than directly manipulating the fields across the kernel. This will make it easier to change the implementation of these statistics, such as using per-CPU versions of the data structures. MFC after: 3 days
* Correct a number of evolved problems with inp_vflag and inp_flags:rwatson2009-03-151-5/+5
| | | | | | | | | | | | | | | | | | | | | certain flags that should have been in inp_flags ended up in inp_vflag, meaning that they were inconsistently locked, and in one case, interpreted. Move the following flags from inp_vflag to gaps in the inp_flags space (and clean up the inp_flags constants to make gaps more obvious to future takers): INP_TIMEWAIT INP_SOCKREF INP_ONESBCAST INP_DROPPED Some aspects of this change have no effect on kernel ABI at all, as these are UDP/TCP/IP-internal uses; however, netstat and sockstat detect INP_TIMEWAIT when listing TCP sockets, so any MFC will need to take this into account. MFC after: 1 week (or after dependencies are MFC'd) Reviewed by: bz
* Add TCP Appropriate Byte Counting (RFC 3465) support to kernel.lstewart2009-01-151-0/+1
| | | | | | | | | | | | | The new behaviour is on by default, and can be disabled by setting the net.inet.tcp.rfc3465 sysctl to 0 to obtain previous behaviour. The patch changes struct tcpcb in sys/netinet/tcp_var.h which breaks the ABI. Bump __FreeBSD_version to 800061 accordingly. User space tools that rely on the size of struct tcpcb (e.g. sockstat) need to be recompiled. Reviewed by: rpaulo, gnn Approved by: gnn, kmacy (mentors) Sponsored by: FreeBSD Foundation
* Rather than using hidden includes (with cicular dependencies),bz2008-12-021-0/+2
| | | | | | | | | | | directly include only the header files needed. This reduces the unneeded spamming of various headers into lots of files. For now, this leaves us with very few modules including vnet.h and thus needing to depend on opt_route.h. Reviewed by: brooks, gnn, des, zec, imp Sponsored by: The FreeBSD Foundation
* Step 1.5 of importing the network stack virtualization infrastructurezec2008-10-021-5/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | from the vimage project, as per plan established at devsummit 08/08: http://wiki.freebsd.org/Image/Notes200808DevSummit Introduce INIT_VNET_*() initializer macros, VNET_FOREACH() iterator macros, and CURVNET_SET() context setting macros, all currently resolving to NOPs. Prepare for virtualization of selected SYSCTL objects by introducing a family of SYSCTL_V_*() macros, currently resolving to their global counterparts, i.e. SYSCTL_V_INT() == SYSCTL_INT(). Move selected #defines from sys/sys/vimage.h to newly introduced header files specific to virtualized subsystems (sys/net/vnet.h, sys/netinet/vinet.h etc.). All the changes are verified to have zero functional impact at this point in time by doing MD5 comparision between pre- and post-change object files(*). (*) netipsec/keysock.c did not validate depending on compile time options. Implemented by: julian, bz, brooks, zec Reviewed by: julian, bz, brooks, kris, rwatson, ... Approved by: julian (mentor) Obtained from: //depot/projects/vimage-commit2/... X-MFC after: never Sponsored by: NLnet Foundation, The FreeBSD Foundation
* Commit step 1 of the vimage project, (network stack)bz2008-08-171-32/+33
| | | | | | | | | | | | | | | | | | | | | | | | virtualization work done by Marko Zec (zec@). This is the first in a series of commits over the course of the next few weeks. Mark all uses of global variables to be virtualized with a V_ prefix. Use macros to map them back to their global names for now, so this is a NOP change only. We hope to have caught at least 85-90% of what is needed so we do not invalidate a lot of outstanding patches again. Obtained from: //depot/projects/vimage-commit2/... Reviewed by: brooks, des, ed, mav, julian, jamie, kris, rwatson, zec, ... (various people I forgot, different versions) md5 (with a bit of help) Sponsored by: NLnet Foundation, The FreeBSD Foundation X-MFC after: never V_Commit_Message_Reviewed_By: more people than the patch
* Document a few sysctls.trhodes2008-07-201-3/+3
| | | | Reviewed by: rwatson
* When allocating temporary storage to hold a TCP/IP packet headerrwatson2008-06-021-1/+1
| | | | | | | | template, use an M_TEMP malloc(9) allocation rather than an mbuf with mtod(9) and dtom(9). This eliminates the last use of dtom(9) in TCP. MFC after: 3 weeks
* Convert pcbinfo and inpcb mutexes to rwlocks, and modify macros torwatson2008-04-171-16/+16
| | | | | | | | | | | | | | | explicitly select write locking for all use of the inpcb mutex. Update some pcbinfo lock assertions to assert locked rather than write-locked, although in practice almost all uses of the pcbinfo rwlock main exclusive, and all instances of inpcb lock acquisition are exclusive. This change should introduce (ideally) little functional change. However, it lays the groundwork for significantly increased parallelism in the TCP/IP code. MFC after: 3 months Tested by: kris (superset of committered patch)
* Add FBSDID to all files in netinet so that people can moresilby2007-10-071-1/+3
| | | | | | easily include file version information in bug reports. Approved by: re (kensmith)
* Revert rev. 1.94. After recent tcp backouts, tcp_close() may return NULL.kib2007-09-241-1/+1
| | | | | | | | Check the return value of tcp_close() being NULL before dereferencing it in #ifdef TCPDEBUG block. Reviewed by: rwatson Approved by: re (gnn)
* Two changes:silby2007-09-241-29/+29
| | | | | | | | | | | | | | | | | | - Reintegrate the ANSI C function declaration change from tcp_timer.c rev 1.92 - Reorganize the tcpcb structure so that it has a single pointer to the "tcp_timer" structure which contains all of the tcp timer callouts. This change means that when the single tcp timer change is reintegrated, tcpcb will not change in size, and therefore the ABI between netstat and the kernel will not change. Neither of these changes should have any functional impact. Reviewed by: bmah, rrs Approved by: re (bmah)
* Back out tcp_timer.c:1.93 and associated changes that reimplemented the manyrwatson2007-09-071-305/+241
| | | | | | | | | | | | | | | | | | | | | | | TCP timers as a single timer, but retain the API changes necessary to reintroduce this change. This will back out the source of at least two reported problems: lock leaks in certain timer edge cases, and TCP timers continuing to fire after a connection has closed (a bug previously fixed and then reintroduced with the timer rewrite). In a follow-up commit, some minor restylings and comment changes performed after the TCP timer rewrite will be reapplied, and a further change to allow the TCP timer rewrite to be added back without disturbing the ABI. The new design is believed to be a good thing, but the outstanding issues are leading to significant stability/correctness problems that are holding up 7.0. This patch was generated by silby, but is being committed by proxy due to poor network connectivity for silby this week. Approved by: re (kensmith) Submitted by: silby Tested by: rwatson, kris Problems reported by: peter, kris, others
* Handle a race condition on >2 core machines in tcp_timer() whenandre2007-06-091-2/+8
| | | | | | | | | a timer issues a shutdown and a simultaneous close on the socket happens. This race condition is inherent in the current socket/ inpcb life cycle system but can be handled well. Reported by: kris Tested by: kris (on 8-core machine)
* In tcp_timer_2msl(), tp can never become NULL, so don't check it forrwatson2007-05-271-1/+1
| | | | | | | NULL before entering tcp_trace(). Found with: Coverity Prevent(tm) CID: 1840
* Move TIME_WAIT related functions and timer handling from filesandre2007-05-161-54/+1
| | | | | | | | | | | | | | | | other than repo copied tcp_subr.c into tcp_timewait.c#1.284: tcp_input.c#1.350 tcp_timewait() -> tcp_twcheck() tcp_timer.c#1.92 tcp_timer_2msl_reset() -> tcp_tw_2msl_reset() tcp_timer.c#1.92 tcp_timer_2msl_stop() -> tcp_tw_2msl_stop() tcp_timer.c#1.92 tcp_timer_2msl_tw() -> tcp_tw_2msl_scan() This is a mechanical move with appropriate renames and making them static if used only locally. The tcp_tw_2msl_scan() cleanup function is still run from the tcp_slowtimo() in tcp_timer.c.
* Move universally to ANSI C function declarations, with relativelyrwatson2007-05-101-3/+1
| | | | consistent style(9)-ish layout.
* Fix two comments.andre2007-05-061-2/+2
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* Change the TCP timer system from using the callout system five timesandre2007-04-111-175/+299
| | | | | | | | | | | | | | | | directly to a merged model where only one callout, the next to fire, is registered. Instead of callout_reset(9) and callout_stop(9) the new function tcp_timer_activate() is used which then internally manages the callout. The single new callout is a mutex callout on inpcb simplifying the locking a bit. tcp_timer() is the called function which handles all race conditions in one place and then dispatches the individual timer functions. Reviewed by: rwatson (earlier version)
* Retire unused TCP_SACK_DEBUG.andre2007-04-041-1/+0
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* ANSIfy function declarations and remove register keywords for variables.andre2007-03-211-10/+5
| | | | Consistently apply style to all function declarations.
* Match up SYSCTL declaration style.andre2007-03-191-6/+9
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* Reap FIN_WAIT_2 connections marked SOCANTRCVMORE faster. This mitigatemohans2007-02-261-6/+26
| | | | | | | | potential issues where the peer does not close, potentially leaving thousands of connections in FIN_WAIT_2. This is controlled by a new sysctl fast_finwait2_recycle, which is disabled by default. Reviewed by: gnn, silby.
* Back when we had T/TCP support, we used to apply differentru2006-09-071-43/+20
| | | | | | | | | | | timeouts for TCP and T/TCP connections in the TIME_WAIT state, and we had two separate timed wait queues for them. Now that is has gone, the timeout is always 2*MSL again, and there is no reason to keep two queues (the first was unused anyway!). Also, reimplement the remaining queue using a TAILQ (it was technically impossible before, with two queues).
* Remove a microoptimization for i386 that was a micropessimization for amd64.ru2006-09-071-2/+1
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* o Backout rev. 1.125 of in_pcb.c. It appeared to behave extremelyglebius2006-09-061-7/+12
| | | | | | | | | | | | | | | | | | | | bad under high load. For example with 40k sockets and 25k tcptw entries, connect() syscall can run for seconds. Debugging showed that it iterates the cycle millions times and purges thousands of tcptw entries at a time. Besides practical unusability this change is architecturally wrong. First, in_pcblookup_local() is used in connect() and bind() syscalls. No stale entries purging shouldn't be done here. Second, it is a layering violation. o Return back the tcptw purging cycle to tcp_timer_2msl_tw(), that was removed in rev. 1.78 by rwatson. The commit log of this revision tells nothing about the reason cycle was removed. Now we need this cycle, since major cleaner of stale tcptw structures is removed. o Disable probably necessary, but now unused tcp_twrecycleable() function. Reviewed by: ru
* Fixes an edge case bug in timewait handling where ticks rolling over causingmohans2006-08-111-4/+3
| | | | | the timewait expiry to be exactly 0 corrupts the timewait queues (and that entry). Reviewed by: silby
* When entering a timer on a tcpcb, don't continue processing if it has beenrwatson2006-06-031-9/+14
| | | | | | | | | | | | dropped. This prevents a bug introduced during the socket/pcb refcounting work from occuring, in which occasionally the retransmit timer may fire after a connection has been reset, resulting in the resulting R|A TCP packet having a source port of 0, as the port reservation has been released. While here, fixing up some RUNLOCK->WUNLOCK bugs. MFC after: 1 month
* - Backout one line from 1.78. The tp can be freed by tcp_drop().glebius2006-05-161-3/+2
| | | | | | - Style next line. Coverity ID: 912
* Only return (tw) from tcp_twclose() if reuse is passed, otherwiserwatson2006-05-051-1/+1
| | | | | | | | | | return NULL. In principle this shouldn't change the behavior, but avoids returning a potentially invalid/inappropriate pointer to the caller. Found with: Coverity Prevent (tm) Submitted by: pjd MFC after: 3 months
* Update TCP for infrastructural changes to the socket/pcb refcount model,rwatson2006-04-011-16/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pru_abort(), pru_detach(), and in_pcbdetach(): - Universally support and enforce the invariant that so_pcb is never NULL, converting dozens of unnecessary NULL checks into assertions, and eliminating dozens of unnecessary error handling cases in protocol code. - In some cases, eliminate unnecessary pcbinfo locking, as it is no longer required to ensure so_pcb != NULL. For example, the receive code no longer requires the pcbinfo lock, and the send code only requires it if building a new connection on an otherwise unconnected socket triggered via sendto() with an address. This should significnatly reduce tcbinfo lock contention in the receive and send cases. - In order to support the invariant that so_pcb != NULL, it is now necessary for the TCP code to not discard the tcpcb any time a connection is dropped, but instead leave the tcpcb until the socket is shutdown. This case is handled by setting INP_DROPPED, to substitute for using a NULL so_pcb to indicate that the connection has been dropped. This requires the inpcb lock, but not the pcbinfo lock. - Unlike all other protocols in the tree, TCP may need to retain access to the socket after the file descriptor has been closed. Set SS_PROTOREF in tcp_detach() in order to prevent the socket from being freed, and add a flag, INP_SOCKREF, so that the TCP code knows whether or not it needs to free the socket when the connection finally does close. The typical case where this occurs is if close() is called on a TCP socket before all sent data in the send socket buffer has been transmitted or acknowledged. If INP_SOCKREF is found when the connection is dropped, we release the inpcb, tcpcb, and socket instead of flagging INP_DROPPED. - Abort and detach protocol switch methods no longer return failures, nor attempt to free sockets, as the socket layer does this. - Annotate the existence of a long-standing race in the TCP timer code, in which timers are stopped but not drained when the socket is freed, as waiting for drain may lead to deadlocks, or have to occur in a context where waiting is not permitted. This race has been handled by testing to see if the tcpcb pointer in the inpcb is NULL (and vice versa), which is not normally permitted, but may be true of a inpcb and tcpcb have been freed. Add a counter to test how often this race has actually occurred, and a large comment for each instance where we compare potentially freed memory with NULL. This will have to be fixed in the near future, but requires is to further address how to handle the timer shutdown shutdown issue. - Several TCP calls no longer potentially free the passed inpcb/tcpcb, so no longer need to return a pointer to indicate whether the argument passed in is still valid. - Un-macroize debugging and locking setup for various protocol switch methods for TCP, as it lead to more obscurity, and as locking becomes more customized to the methods, offers less benefit. - Assert copyright on tcp_usrreq.c due to significant modifications that have been made as part of this work. These changes significantly modify the memory management and connection logic of our TCP implementation, and are (as such) High Risk Changes, and likely to contain serious bugs. Please report problems to the current@ mailing list ASAP, ideally with simple test cases, and optionally, packet traces. MFC after: 3 months
* Explicitly assert socket pointer is non-NULL in tcp_input() so as torwatson2006-03-261-8/+8
| | | | | | | | | provide better debugging information. Prefer explicit comparison to NULL for tcpcb pointers rather than treating them as booleans. MFC after: 1 month
* Make sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS) generally available insteadandre2006-02-161-20/+0
| | | | | | | of being private to tcp_timer.c. Sponsored by: TCP/IP Optimization Fundraise 2005 MFC after: 3 days
* Remove no-op spl's and most comment references to spls, as TCP lockingrwatson2005-07-191-16/+0
| | | | | | is believed to be basically done (modulo any remaining bugs). MFC after: 3 days
* Replace t_force with a t_flag (TF_FORCEDATA).ps2005-05-211-2/+2
| | | | | Submitted by: Raja Mukerji. Reviewed by: Mohan, Silby, Andre Opperman.
* /* -> /*- for license, minor formatting changesimp2005-01-071-1/+1
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* Remove the now unused tcp_canceltimers() function. tcpcb timers arerwatson2004-12-231-15/+0
| | | | | | now stopped as part of tcp_discardcb(). MFC after: 2 weeks
* Remove an annotation of a minor race relating to the update ofrwatson2004-12-231-7/+0
| | | | | | | | | multiple MIB entries using sysctl in short order, which might result in unexpected values for tcp_maxidle being generated by tcp_slowtimo. In practice, this will not happen, or at least, doesn't require an explicit comment. MFC after: 2 weeks
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