kernel/net/ipv4/tcp_illinois.c, branch linux-6.2.y

tcp: add accessors to read/set tp->snd_cwnd

2022-04-06T19:05:41Z

We had various bugs over the years with code breaking the assumption that tp->snd_cwnd is greater than zero. Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction") can trigger, and without a repro we would have to spend considerable time finding the bug. Instead of complaining too late, we want to catch where and when tp->snd_cwnd is set to an illegal value. Signed-off-by: Eric Dumazet Suggested-by: Yuchung Cheng Cc: Neal Cardwell Acked-by: Yuchung Cheng Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski

treewide: Add SPDX license identifier for more missed files

2019-05-21T08:50:45Z

Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

net/tcp/illinois: replace broken algorithm reference link

2018-02-28T17:03:47Z

The link to the pdf containing the algorithm description is now a dead link; it seems http://www.ifp.illinois.edu/~srikant/ has been moved to https://sites.google.com/a/illinois.edu/srikant/ and none of the original papers can be found there... I have replaced it with the only working copy I was able to find. n.b. there is also a copy available at: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.296.6350&rep=rep1&type=pdf However, this seems to only be a *cached* version, so I am unsure exactly how reliable that link can be expected to remain over time and have decided against using that one. Signed-off-by: Joey Pabalinas 1 file changed, 1 insertion(+), 1 deletion(-) Signed-off-by: David S. Miller

tcp: consolidate congestion control undo functions

2017-08-07T04:25:10Z

Most TCP congestion controls are using identical logic to undo cwnd except BBR. This patch consolidates these similar functions to the one used currently by Reno and others. Suggested-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Signed-off-by: David S. Miller

tcp: add cwnd_undo functions to various tcp cc algorithms

2016-11-21T18:20:17Z

congestion control algorithms that do not halve cwnd in their .ssthresh should provide a .cwnd_undo rather than rely on current fallback which assumes reno halving (and thus doubles the cwnd). All of these do 'something else' in their .ssthresh implementation, thus store the cwnd on loss and provide .undo_cwnd to restore it again. A followup patch will remove the fallback and all algorithms will need to provide a .cwnd_undo function. Signed-off-by: Florian Westphal Signed-off-by: David S. Miller

tcp: replace cnt & rtt with struct in pkts_acked()

2016-05-11T18:43:19Z

Replace 2 arguments (cnt and rtt) in the congestion control modules' pkts_acked() function with a struct. This will allow adding more information without having to modify existing congestion control modules (tcp_nv in particular needs bytes in flight when packet was sent). As proposed by Neal Cardwell in his comments to the tcp_nv patch. Signed-off-by: Lawrence Brakmo Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: add tcp_in_slow_start helper

2015-07-09T21:22:52Z

Add a helper to test the slow start condition in various congestion control modules and other places. This is to prepare a slight improvement in policy as to exactly when to slow start. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Signed-off-by: Eric Dumazet Signed-off-by: Nandita Dukkipati Signed-off-by: David S. Miller

tcp: prepare CC get_info() access from getsockopt()

2015-04-29T21:10:38Z

We would like that optional info provided by Congestion Control modules using netlink can also be read using getsockopt() This patch changes get_info() to put this information in a buffer, instead of skb, like tcp_get_info(), so that following patch can reuse this common infrastructure. Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Cc: Neal Cardwell Acked-by: Neal Cardwell Acked-by: Daniel Borkmann Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

inet_diag: fix access to tcp cc information

2015-04-17T17:28:31Z

Two different problems are fixed here : 1) inet_sk_diag_fill() might be called without socket lock held. icsk->icsk_ca_ops can change under us and module be unloaded. -> Access to freed memory. Fix this using rcu_read_lock() to prevent module unload. 2) Some TCP Congestion Control modules provide information but again this is not safe against icsk->icsk_ca_ops change and nla_put() errors were ignored. Some sockets could not get the additional info if skb was almost full. Fix this by returning a status from get_info() handlers and using rcu protection as well. Signed-off-by: Eric Dumazet Acked-by: Daniel Borkmann Signed-off-by: David S. Miller

tcp: whitespace fixes

2014-09-02T01:12:45Z

Fix places where there is space before tab, long lines, and awkward if(){, double spacing etc. Add blank line after declaration/initialization. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller