user/sven/linux.git/net/ipv4, branch v3.4.40

tcp: undo spurious timeout after SACK reneging

2013-04-05T17:04:38Z

[ Upstream commit 7ebe183c6d444ef5587d803b64a1f4734b18c564 ] On SACK reneging the sender immediately retransmits and forces a timeout but disables Eifel (undo). If the (buggy) receiver does not drop any packet this can trigger a false slow-start retransmit storm driven by the ACKs of the original packets. This can be detected with undo and TCP timestamps. Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: preserve ACK clocking in TSO

2013-04-05T17:04:38Z

[ Upstream commit f4541d60a449afd40448b06496dcd510f505928e ] A long standing problem with TSO is the fact that tcp_tso_should_defer() rearms the deferred timer, while it should not. Current code leads to following bad bursty behavior : 20:11:24.484333 IP A > B: . 297161:316921(19760) ack 1 win 119 20:11:24.484337 IP B > A: . ack 263721 win 1117 20:11:24.485086 IP B > A: . ack 265241 win 1117 20:11:24.485925 IP B > A: . ack 266761 win 1117 20:11:24.486759 IP B > A: . ack 268281 win 1117 20:11:24.487594 IP B > A: . ack 269801 win 1117 20:11:24.488430 IP B > A: . ack 271321 win 1117 20:11:24.489267 IP B > A: . ack 272841 win 1117 20:11:24.490104 IP B > A: . ack 274361 win 1117 20:11:24.490939 IP B > A: . ack 275881 win 1117 20:11:24.491775 IP B > A: . ack 277401 win 1117 20:11:24.491784 IP A > B: . 316921:332881(15960) ack 1 win 119 20:11:24.492620 IP B > A: . ack 278921 win 1117 20:11:24.493448 IP B > A: . ack 280441 win 1117 20:11:24.494286 IP B > A: . ack 281961 win 1117 20:11:24.495122 IP B > A: . ack 283481 win 1117 20:11:24.495958 IP B > A: . ack 285001 win 1117 20:11:24.496791 IP B > A: . ack 286521 win 1117 20:11:24.497628 IP B > A: . ack 288041 win 1117 20:11:24.498459 IP B > A: . ack 289561 win 1117 20:11:24.499296 IP B > A: . ack 291081 win 1117 20:11:24.500133 IP B > A: . ack 292601 win 1117 20:11:24.500970 IP B > A: . ack 294121 win 1117 20:11:24.501388 IP B > A: . ack 295641 win 1117 20:11:24.501398 IP A > B: . 332881:351881(19000) ack 1 win 119 While the expected behavior is more like : 20:19:49.259620 IP A > B: . 197601:202161(4560) ack 1 win 119 20:19:49.260446 IP B > A: . ack 154281 win 1212 20:19:49.261282 IP B > A: . ack 155801 win 1212 20:19:49.262125 IP B > A: . ack 157321 win 1212 20:19:49.262136 IP A > B: . 202161:206721(4560) ack 1 win 119 20:19:49.262958 IP B > A: . ack 158841 win 1212 20:19:49.263795 IP B > A: . ack 160361 win 1212 20:19:49.264628 IP B > A: . ack 161881 win 1212 20:19:49.264637 IP A > B: . 206721:211281(4560) ack 1 win 119 20:19:49.265465 IP B > A: . ack 163401 win 1212 20:19:49.265886 IP B > A: . ack 164921 win 1212 20:19:49.266722 IP B > A: . ack 166441 win 1212 20:19:49.266732 IP A > B: . 211281:215841(4560) ack 1 win 119 20:19:49.267559 IP B > A: . ack 167961 win 1212 20:19:49.268394 IP B > A: . ack 169481 win 1212 20:19:49.269232 IP B > A: . ack 171001 win 1212 20:19:49.269241 IP A > B: . 215841:221161(5320) ack 1 win 119 Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Cc: Van Jacobson Cc: Neal Cardwell Cc: Nandita Dukkipati Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

inet: limit length of fragment queue hash table bucket lists

2013-03-28T19:11:54Z

[ Upstream commit 5a3da1fe9561828d0ca7eca664b16ec2b9bf0055 ] This patch introduces a constant limit of the fragment queue hash table bucket list lengths. Currently the limit 128 is choosen somewhat arbitrary and just ensures that we can fill up the fragment cache with empty packets up to the default ip_frag_high_thresh limits. It should just protect from list iteration eating considerable amounts of cpu. If we reach the maximum length in one hash bucket a warning is printed. This is implemented on the caller side of inet_frag_find to distinguish between the different users of inet_fragment.c. I dropped the out of memory warning in the ipv4 fragment lookup path, because we already get a warning by the slab allocator. Cc: Eric Dumazet Cc: Jesper Dangaard Brouer Signed-off-by: Hannes Frederic Sowa Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: fix skb_availroom()

2013-03-28T19:11:53Z

[ Upstream commit 16fad69cfe4adbbfa813de516757b87bcae36d93 ] Chrome OS team reported a crash on a Pixel ChromeBook in TCP stack : https://code.google.com/p/chromium/issues/detail?id=182056 commit a21d45726acac (tcp: avoid order-1 allocations on wifi and tx path) did a poor choice adding an 'avail_size' field to skb, while what we really needed was a 'reserved_tailroom' one. It would have avoided commit 22b4a4f22da (tcp: fix retransmit of partially acked frames) and this commit. Crash occurs because skb_split() is not aware of the 'avail_size' management (and should not be aware) Signed-off-by: Eric Dumazet Reported-by: Mukesh Agrawal Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/ipv4: Ensure that location of timestamp option is stored

2013-03-28T19:11:52Z

[ Upstream commit 4660c7f498c07c43173142ea95145e9dac5a6d14 ] This is needed in order to detect if the timestamp option appears more than once in a packet, to remove the option if the packet is fragmented, etc. My previous change neglected to store the option location when the router addresses were prespecified and Pointer > Length. But now the option location is also stored when Flag is an unrecognized value, to ensure these option handling behaviors are still performed. Signed-off-by: David Ward Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: fix double-counted receiver RTT when leaving receiver fast path

2013-03-20T20:05:01Z

[ Upstream commit aab2b4bf224ef8358d262f95b568b8ad0cecf0a0 ] We should not update ts_recent and call tcp_rcv_rtt_measure_ts() both before and after going to step5. That wastes CPU and double-counts the receiver-side RTT sample. Signed-off-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: use a stronger hash for tcp

2013-02-28T14:59:06Z

[ Upstream commit 08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664 ] It looks like its possible to open thousands of TCP IPv6 sessions on a server, all landing in a single slot of TCP hash table. Incoming packets have to lookup sockets in a very long list. We should hash all bits from foreign IPv6 addresses, using a salt and hash mix, not a simple XOR. inet6_ehashfn() can also separately use the ports, instead of xoring them. Reported-by: Neal Cardwell Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv4: fix a bug in ping_err().

2013-02-28T14:59:06Z

[ Upstream commit b531ed61a2a2a77eeb2f7c88b49aa5ec7d9880d8 ] We should get 'type' and 'code' from the outer ICMP header. Signed-off-by: Li Wei Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: fix for zero packets_in_flight was too broad

2013-02-14T18:49:06Z

[ Upstream commit 6731d2095bd4aef18027c72ef845ab1087c3ba63 ] There are transients during normal FRTO procedure during which the packets_in_flight can go to zero between write_queue state updates and firing the resulting segments out. As FRTO processing occurs during that window the check must be more precise to not match "spuriously" :-). More specificly, e.g., when packets_in_flight is zero but FLAG_DATA_ACKED is true the problematic branch that set cwnd into zero would not be taken and new segments might be sent out later. Signed-off-by: Ilpo Järvinen Tested-by: Eric Dumazet Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: frto should not set snd_cwnd to 0

2013-02-14T18:49:06Z

[ Upstream commit 2e5f421211ff76c17130b4597bc06df4eeead24f ] Commit 9dc274151a548 (tcp: fix ABC in tcp_slow_start()) uncovered a bug in FRTO code : tcp_process_frto() is setting snd_cwnd to 0 if the number of in flight packets is 0. As Neal pointed out, if no packet is in flight we lost our chance to disambiguate whether a loss timeout was spurious. We should assume it was a proper loss. Reported-by: Pasi Kärkkäinen Signed-off-by: Neal Cardwell Signed-off-by: Eric Dumazet Cc: Ilpo Järvinen Cc: Yuchung Cheng Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman