Previously TCP had a transitional state during which reno
counted segments that are already below the current window into
sacked_out, which is now prevented. In addition, re-try now
the unconditional S+L skb catching.
This approach conservatively calls just remove_sack and leaves
reset_sack() calls alone. The best solution to the whole problem
would be to first calculate the new sacked_out fully (this patch
does not move reno_sack_reset calls from original sites and thus
does not implement this). However, that would require very
invasive change to fastretrans_alert (perhaps even slicing it to
two halves). Alternatively, all callers of tcp_packets_in_flight
(i.e., users that depend on sacked_out) should be postponed
until the new sacked_out has been calculated but it isn't any
simpler alternative.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This happens rather infrequently and is only possible during
FRTO. We must not allow TCP to slip to Open state because
tcp_fastretrans_alert might then not be called on it's time
when FRTO has exited. This become a problem when left_out
got removed and was replaced by just sacked_out.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_verify_left_out is useful for verifying S+L condition, so
add it back to couple of places in where the code was not
calling to tcp_sync_left_out but used own ad-hoc solution
(before the tcp_sync_left_out got removed).
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Left_out was dropped a while ago, thus leaving verifying
consistency of the "left out" as only task for the function in
question. Thus make it's name more appropriate.
In addition, it is intentionally converted to #define instead
of static inline because the location of the invariant failure
is the most important thing to have if this ever triggers. I
think it would have been helpful e.g. in this case where the
location of the failure point had to be based on some quesswork:
http://lkml.org/lkml/2007/5/2/464
...Luckily the guesswork seems to have proved to be correct.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
tp->left_out got removed but nothing came to replace it back
then (users just did addition by themselves), so add function
for users now.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is easily calculable when needed and user are not that many
after all.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no need for such check in pkts_acked because the
callback is not invoked unless at least one segment got fully
ACKed (i.e., the snd_una moved past skb's end_seq) by the
cumulative ACK's snd_una advancement.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
No other users exist for tcp_ecn.h. Very few things remain in
tcp.h, for most TCP ECN functions callers reside within a
single .c file and can be placed there.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
In addition, added a reference about the purpose of the loop.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
F-RTO does not touch SACKED_ACKED bits at all, so there is no
need to recount them in tcp_enter_frto_loss. After removal of
the else branch, nested ifs can be combined.
This must also reset sacked_out when SACK is not in use as TCP
could have received some duplicate ACKs prior RTO. To achieve
that in a sane manner, tcp_reset_reno_sack was re-placed by the
previous patch.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stupid error from my side. Even though now that I noticed this,
I hoped it would have been an optimization but no, the counter
hint is then incorrect. Thus clearing is necessary for now (I
still suspect though that this path is never executed).
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is guaranteed to be valid only when !tp->sacked_out. In most
cases this seqno is available in the last ACK but there is no
guarantee for that. The new fast recovery loss marking algorithm
needs this as entry point.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch provides generic Large Receive Offload (LRO) functionality
for IPv4/TCP traffic.
LRO combines received tcp packets to a single larger tcp packet and
passes them then to the network stack in order to increase performance
(throughput). The interface supports two modes: Drivers can either
pass SKBs or fragment lists to the LRO engine.
Signed-off-by: Jan-Bernd Themann <themann@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When only GSO skb was partially ACKed, no hints are reset,
therefore fastpath_cnt_hint must be tweaked too or else it can
corrupt fackets_out. The corruption to occur, one must have
non-trivial ACK/SACK sequence, so this bug is not very often
that harmful. There's a fackets_out state reset in TCP because
fackets_out is known to be inaccurate and that fixes the issue
eventually anyway.
In case there was also at least one skb that got fully ACKed,
the fastpath_skb_hint is set to NULL which causes a recount for
fastpath_cnt_hint (the old value won't be accessed anymore),
thus it can safely be decremented without additional checking.
Reported by Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based upon a report and initial patch by Peter Lieven.
tcp4_md5sig_key and tcp6_md5sig_key need to start with
the exact same members as tcp_md5sig_key. Because they
are both cast to that type by tcp_v{4,6}_md5_do_lookup().
Unfortunately tcp{4,6}_md5sig_key use a u16 for the key
length instead of a u8, which is what tcp_md5sig_key
uses. This just so happens to work by accident on
little-endian, but on big-endian it doesn't.
Instead of casting, just place tcp_md5sig_key as the first member of
the address-family specific structures, adjust the access sites, and
kill off the ugly casts.
Signed-off-by: David S. Miller <davem@davemloft.net>
So I've had a deadlock reported to me. I've found that the sequence of
events goes like this:
1) process A (modprobe) runs to remove ip_tables.ko
2) process B (iptables-restore) runs and calls setsockopt on a netfilter socket,
increasing the ip_tables socket_ops use count
3) process A acquires a file lock on the file ip_tables.ko, calls remove_module
in the kernel, which in turn executes the ip_tables module cleanup routine,
which calls nf_unregister_sockopt
4) nf_unregister_sockopt, seeing that the use count is non-zero, puts the
calling process into uninterruptible sleep, expecting the process using the
socket option code to wake it up when it exits the kernel
4) the user of the socket option code (process B) in do_ipt_get_ctl, calls
ipt_find_table_lock, which in this case calls request_module to load
ip_tables_nat.ko
5) request_module forks a copy of modprobe (process C) to load the module and
blocks until modprobe exits.
6) Process C. forked by request_module process the dependencies of
ip_tables_nat.ko, of which ip_tables.ko is one.
7) Process C attempts to lock the request module and all its dependencies, it
blocks when it attempts to lock ip_tables.ko (which was previously locked in
step 3)
Theres not really any great permanent solution to this that I can see, but I've
developed a two part solution that corrects the problem
Part 1) Modifies the nf_sockopt registration code so that, instead of using a
use counter internal to the nf_sockopt_ops structure, we instead use a pointer
to the registering modules owner to do module reference counting when nf_sockopt
calls a modules set/get routine. This prevents the deadlock by preventing set 4
from happening.
Part 2) Enhances the modprobe utilty so that by default it preforms non-blocking
remove operations (the same way rmmod does), and add an option to explicity
request blocking operation. So if you select blocking operation in modprobe you
can still cause the above deadlock, but only if you explicity try (and since
root can do any old stupid thing it would like.... :) ).
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we're now using a generic tuple decoding function in ICMP
connection tracking, ipv4_get_l4proto() might get called with a
fragmented packet from within an ICMP error. Remove the error
message we used to print when this happens.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bug: http://bugzilla.kernel.org/show_bug.cgi?id=8876
Not all ips are shown by "ip addr show" command when IPs number assigned to an
interface is more than 60-80 (in fact it depends on broadcast/label etc
presence on each address).
Steps to reproduce:
It's terribly simple to reproduce:
# for i in $(seq 1 100); do ip ad add 10.0.$i.1/24 dev eth10 ; done
# ip addr show
this will _not_ show all IPs.
Looks like the problem is in netlink/ipv4 message processing.
This is fix from bug submitter, it looks correct.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cell phone networks do link layer retransmissions and other
things that cause unnecessary timeout retransmits. So allow
the minimum RTO to be inflated per-route to deal with this.
Signed-off-by: David S. Miller <davem@davemloft.net>
People often get tripped up by this function and think that
it does not implemented the prescribed algorithms from
RFC2414 and RFC3390, even though it does.
So add a comment to head off such misunderstandings in the
future.
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix IP[V6]_ADD_MEMBERSHIP and IP[V6]_DROP_MEMBERSHIP to
return -EPROTO for connection oriented sockets.
Signed-off-by: Flavio Leitner <fleitner@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In testing our ESP/AH offload hardware, I discovered an issue with how
AH handles mutable fields in IPv4. RFC 4302 (AH) states the following
on the subject:
For IPv4, the entire option is viewed as a unit; so even
though the type and length fields within most options are immutable
in transit, if an option is classified as mutable, the entire option
is zeroed for ICV computation purposes.
The current implementation does not zero the type and length fields,
resulting in authentication failures when communicating with hosts
that do (i.e. FreeBSD).
I have tested record route and timestamp options (ping -R and ping -T)
on a small network involving Windows XP, FreeBSD 6.2, and Linux hosts,
with one router. In the presence of these options, the FreeBSD and
Linux hosts (with the patch or with the hardware) can communicate.
The Windows XP host simply fails to accept these packets with or
without the patch.
I have also been trying to test source routing options (using
traceroute -g), but haven't had much luck getting this option to work
*without* AH, let alone with.
Signed-off-by: Nick Bowler <nbowler@ellipticsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't drop packets shorter than "SIP/2.0", just ignore them. Keep-alives
can validly be shorter for example.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
For architectures that don't have a volatile atomic_ts constructs like
while (atomic_read(&something)); might result in endless loops since a
barrier() is missing which forces the compiler to generate code that
actually reads memory contents.
Fix this in ipvs by using the IP_VS_WAIT_WHILE macro which resolves to
while (expr) { cpu_relax(); }
(why isn't this open coded btw?)
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch cleans up duplicate includes in
net/ipv4/
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The following commandline:
root=/dev/mtdblock6 rw rootfstype=jffs2 ip=192.168.1.10:::255.255.255.0:localhost.localdomain:eth1:off console=ttyS0,115200
makes ip_auto_config fall back to DHCP and complain "IP-Config: Incomplete
network configuration information." depending on if CONFIG_IP_PNP_DHCP is
set or not.
The only way I can make ip_auto_config accept my IP config is to add an
entry for the server IP:
ip=192.168.1.10:192.168.1.15::255.255.255.0:localhost.localdomain:eth1:off
I think this is a bug since I am not using a NFS root FS.
The following patch fixes the above problem.
From: Andrew Morton <akpm@linux-foundation.org>
Davem said (in February!):
Well, first of all the change in question is not in 2.4.x either. I just
checked the current 2.4.x GIT tree and the test is exactly:
if (ic_myaddr == INADDR_NONE ||
#ifdef CONFIG_ROOT_NFS
(MAJOR(ROOT_DEV) == UNNAMED_MAJOR
&& root_server_addr == INADDR_NONE
&& ic_servaddr == INADDR_NONE) ||
#endif
ic_first_dev->next) {
which matches 2.6.x
I even checked 2.4.x when it was branched for 2.5.x and the test was the
same at the point in time too.
Looking at the proposed change a bit it appears that it is probably
correct, as it's trying to check that ROOT_DEV is nfs root. But if it is
correct then the UNNAMED_MAJOR comparison in the same code block should be
removed as it becomes superfluous.
I'm happy to apply this patch with that modification made.
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Small patch to H-TCP from Douglas Leith.
Fix estimation of maxRTT. The original code ignores rtt measurements
during slow start (via the check tp->snd_ssthresh < 0xFFFF) yet this
is probably a good time to try to estimate max rtt as delayed acking
is disabled and slow start will only exit on a loss which presumably
corresponds to a maxrtt measurement. Second, the original code (via
the check htcp_ccount(ca) > 3) ignores rtt data during what it
estimates to be the first 3 round-trip times. This seems like an
unnecessary check now that the RCV timestamp are no longer used
for rtt estimation.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Loading nf_nat causes the conntrack core to be loaded, but we need IPv4 as
well.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the call to seq_open() returns != 0 then the code calls
kfree(st) but then on the very next line proceeds to
dereference the pointer - not good.
Problem spotted by the Coverity checker.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In case a DSACK is received, it's better to lower cwnd as it's
a sign of data receival.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_cwnd_down must check for it too as it should be conservative
in case of collapse stuff and also when receiver is trying to
lie (though that wouldn't be very successful/useful anyway).
Note:
- Separated also is_dupack and do_lost in fast_retransalert
* Much cleaner look-and-feel now
* This time it really fixes cumulative ACK with many new
SACK blocks recovery entry (I claimed this fixes with
last patch but it wasn't). TCP will now call
tcp_update_scoreboard regardless of is_dupack when
in recovery as long as there is enough fackets_out.
- Introduce FLAG_SND_UNA_ADVANCED
* Some prior_snd_una arguments are unnecessary after it
- Added helper FLAG_ANY_PROGRESS to avoid long FLAG...|FLAG...
constructs
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
As discovered by Evegniy Polyakov, if we try to sendmsg after
a connection reset, we can do incredibly stupid things.
The core issue is that inet_sendmsg() tries to autobind the
socket, but we should never do that for TCP. Instead we should
just go straight into TCP's sendmsg() code which will do all
of the necessary state and pending socket error checks.
TCP's sendpage already directly vectors to tcp_sendpage(), so this
merely brings sendmsg() in line with that.
Signed-off-by: David S. Miller <davem@davemloft.net>
It's possible that new SACK blocks that should trigger new LOST
markings arrive with new data (which previously made is_dupack
false). In addition, I think this fixes a case where we get
a cumulative ACK with enough SACK blocks to trigger the fast
recovery (is_dupack would be false there too).
I'm not completely pleased with this solution because readability
of the code is somewhat questionable as 'is_dupack' in SACK case
is no longer about dupacks only but would mean something like
'lost_marker_work_todo' too... But because of Eifel stuff done
in CA_Recovery, the FLAG_DATA_SACKED check cannot be placed to
the if statement which seems attractive solution. Nevertheless,
I didn't like adding another variable just for that either... :-)
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Actually, the ratehalving seems to work too well, as cwnd is
reduced on every second ACK even though the packets in flight
remains unchanged. Recoveries in a bidirectional flows suffer
quite badly because of this, both NewReno and SACK are affected.
After this patch, rate halving is performed for ACK only if
packets in flight was supposedly changed too.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that netdev notifications can fail, we can use this to signal
errors during registration for IPv4/IPv6. In particular, if we
fail to allocate memory for the inet device, we can fail the netdev
registration.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
As a path that forwards packets, IPVS should be using
skb_forward_csum instead of directly setting ip_summed
to CHECKSUM_NONE.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change HTCP to use measured RTT rather than smooth RTT.
Srtt is computed using the TCP receive timestamp
options, so it is vulnerable to hostile receivers. To avoid any problems
this might cause use the measured RTT instead.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove use of received timestamp option value from RTT calculation in Cubic.
A hostile receiver may be returning a larger timestamp option than the original
value. This would cause the sender to believe the malevolent receiver had
a larger RTT and because Cubic tries to provide some RTT friendliness, the
sender would then favor the liar.
Instead, use the jiffie resolutionRTT value already computed and
passed back after ack.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch changes the API for the callback that is done after an ACK is
received. It solves a couple of issues:
* Some congestion controls want higher resolution value of RTT
(controlled by TCP_CONG_RTT_SAMPLE flag). These don't really want a ktime, but
all compute a RTT in microseconds.
* Other congestion control could use RTT at jiffies resolution.
To keep API consistent the units should be the same for both cases, just the
resolution should change.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
