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* Documentation: ip-sysctl.txt: clarify secure_redirectsEric Garver2016-05-301-3/+5
| | | | | | | Clarify how secure_redirects works. Mention that RFC1122 always applies. Signed-off-by: Eric Garver <e@erig.me> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: ipv4: Consider failed nexthops in multipath routesDavid Ahern2016-04-111-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multipath route lookups should consider knowledge about next hops and not select a hop that is known to be failed. Example: [h2] [h3] 15.0.0.5 | | 3| 3| [SP1] [SP2]--+ 1 2 1 2 | | /-------------+ | | \ / | | X | | / \ | | / \---------------\ | 1 2 1 2 12.0.0.2 [TOR1] 3-----------------3 [TOR2] 12.0.0.3 4 4 \ / \ / \ / -------| |-----/ 1 2 [TOR3] 3| | [h1] 12.0.0.1 host h1 with IP 12.0.0.1 has 2 paths to host h3 at 15.0.0.5: root@h1:~# ip ro ls ... 12.0.0.0/24 dev swp1 proto kernel scope link src 12.0.0.1 15.0.0.0/16 nexthop via 12.0.0.2 dev swp1 weight 1 nexthop via 12.0.0.3 dev swp1 weight 1 ... If the link between tor3 and tor1 is down and the link between tor1 and tor2 then tor1 is effectively cut-off from h1. Yet the route lookups in h1 are alternating between the 2 routes: ping 15.0.0.5 gets one and ssh 15.0.0.5 gets the other. Connections that attempt to use the 12.0.0.2 nexthop fail since that neighbor is not reachable: root@h1:~# ip neigh show ... 12.0.0.3 dev swp1 lladdr 00:02:00:00:00:1b REACHABLE 12.0.0.2 dev swp1 FAILED ... The failed path can be avoided by considering known neighbor information when selecting next hops. If the neighbor lookup fails we have no knowledge about the nexthop, so give it a shot. If there is an entry then only select the nexthop if the state is sane. This is similar to what fib_detect_death does. To maintain backward compatibility use of the neighbor information is based on a new sysctl, fib_multipath_use_neigh. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Reviewed-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
* igmp: Document sysctl_igmp_max_msfBenjamin Poirier2016-03-221-3/+8
| | | | | Signed-off-by: Benjamin Poirier <bpoirier@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Fix indentation of the conf/ documentation blockBenjamin Poirier2016-03-221-5/+5
| | | | | | | | | | | Commit d67ef35fff67 ("clarify documentation for net.ipv4.igmp_max_memberships") mistakenly indented a block of documentation such that it now looks like it belongs to a specific sysctl. Restore that block's original position. Cc: Jeremy Eder <jeder@redhat.com> Signed-off-by: Benjamin Poirier <bpoirier@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: ipv6: Make address flushing on ifdown optionalDavid Ahern2016-02-261-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, all ipv6 addresses are flushed when the interface is configured down, including global, static addresses: $ ip -6 addr show dev eth1 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000 inet6 2100:1::2/120 scope global valid_lft forever preferred_lft forever inet6 fe80::e0:f9ff:fe79:34bd/64 scope link valid_lft forever preferred_lft forever $ ip link set dev eth1 down $ ip -6 addr show dev eth1 << nothing; all addresses have been flushed>> Add a new sysctl to make this behavior optional. The new setting defaults to flush all addresses to maintain backwards compatibility. When the set global addresses with no expire times are not flushed on an admin down. The sysctl is per-interface or system-wide for all interfaces $ sysctl -w net.ipv6.conf.eth1.keep_addr_on_down=1 or $ sysctl -w net.ipv6.conf.all.keep_addr_on_down=1 Will keep addresses on eth1 on an admin down. $ ip -6 addr show dev eth1 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000 inet6 2100:1::2/120 scope global valid_lft forever preferred_lft forever inet6 fe80::e0:f9ff:fe79:34bd/64 scope link valid_lft forever preferred_lft forever $ ip link set dev eth1 down $ ip -6 addr show dev eth1 3: eth1: <BROADCAST,MULTICAST> mtu 1500 state DOWN qlen 1000 inet6 2100:1::2/120 scope global tentative valid_lft forever preferred_lft forever inet6 fe80::e0:f9ff:fe79:34bd/64 scope link tentative valid_lft forever preferred_lft forever Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: add option to drop unsolicited neighbor advertisementsJohannes Berg2016-02-111-0/+7
| | | | | | | | | | | | In certain 802.11 wireless deployments, there will be NA proxies that use knowledge of the network to correctly answer requests. To prevent unsolicitd advertisements on the shared medium from being a problem, on such deployments wireless needs to drop them. Enable this by providing an option called "drop_unsolicited_na". Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: add option to drop unicast encapsulated in L2 multicastJohannes Berg2016-02-111-0/+6
| | | | | | | | | | | | | | In order to solve a problem with 802.11, the so-called hole-196 attack, add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if enabled, causes the stack to drop IPv6 unicast packets encapsulated in link-layer multi- or broadcast frames. Such frames can (as an attack) be created by any member of the same wireless network and transmitted as valid encrypted frames since the symmetric key for broadcast frames is shared between all stations. Reviewed-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv4: add option to drop gratuitous ARP packetsJohannes Berg2016-02-111-0/+6
| | | | | | | | | | | | In certain 802.11 wireless deployments, there will be ARP proxies that use knowledge of the network to correctly answer requests. To prevent gratuitous ARP frames on the shared medium from being a problem, on such deployments wireless needs to drop them. Enable this by providing an option called "drop_gratuitous_arp". Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv4: add option to drop unicast encapsulated in L2 multicastJohannes Berg2016-02-111-0/+7
| | | | | | | | | | | | | | | | | In order to solve a problem with 802.11, the so-called hole-196 attack, add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if enabled, causes the stack to drop IPv4 unicast packets encapsulated in link-layer multi- or broadcast frames. Such frames can (as an attack) be created by any member of the same wireless network and transmitted as valid encrypted frames since the symmetric key for broadcast frames is shared between all stations. Additionally, enabling this option provides compliance with a SHOULD clause of RFC 1122. Reviewed-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: change tcp_syn_retries documentationXin Long2016-01-211-1/+1
| | | | | | | | | | Documentation should be kept consistent with the code: static int tcp_syn_retries_max = MAX_TCP_SYNCNT; #define MAX_TCP_SYNCNT 127 Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Allow accepted sockets to be bound to l3mdev domainDavid Ahern2015-12-181-0/+8
| | | | | | | | | | | | | | | | | Allow accepted sockets to derive their sk_bound_dev_if setting from the l3mdev domain in which the packets originated. A sysctl setting is added to control the behavior which is similar to sk_mark and sysctl_tcp_fwmark_accept. This effectively allow a process to have a "VRF-global" listen socket, with child sockets bound to the VRF device in which the packet originated. A similar behavior can be achieved using sk_mark, but a solution using marks is incomplete as it does not handle duplicate addresses in different L3 domains/VRFs. Allowing sockets to inherit the sk_bound_dev_if from l3mdev domain provides a complete solution. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sctp: dynamically enable or disable pf stateZhu Yanjun2015-12-161-1/+22
| | | | | | | | | | | | | | | | | | As we all know, the value of pf_retrans >= max_retrans_path can disable pf state. The variables of pf_retrans and max_retrans_path can be changed by the userspace application. Sometimes the user expects to disable pf state while the 2 variables are changed to enable pf state. So it is necessary to introduce a new variable to disable pf state. According to the suggestions from Vlad Yasevich, extra1 and extra2 are removed. The initialization of pf_enable is added. Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: Zhu Yanjun <zyjzyj2000@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Documentation: Fix default value tcp_limit_output_bytesNiklas Cassel2015-11-091-1/+1
| | | | | | | | Commit c39c4c6abb89 ("tcp: double default TSQ output bytes limit") updated default value for tcp_limit_output_bytes Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge branch 'master' of ↵David S. Miller2015-10-301-2/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next Steffen Klassert says: ==================== pull request (net-next): ipsec-next 2015-10-30 1) The flow cache is limited by the flow cache limit which depends on the number of cpus and the xfrm garbage collector threshold which is independent of the number of cpus. This leads to the fact that on systems with more than 16 cpus we hit the xfrm garbage collector limit and refuse new allocations, so new flows are dropped. On systems with 16 or less cpus, we hit the flowcache limit. In this case, we shrink the flow cache instead of refusing new flows. We increase the xfrm garbage collector threshold to INT_MAX to get the same behaviour, independent of the number of cpus. 2) Fix some unaligned accesses on sparc systems. From Sowmini Varadhan. 3) Fix some header checks in _decode_session4. We may call pskb_may_pull with a negative value converted to unsigened int from pskb_may_pull. This can lead to incorrect policy lookups. We fix this by a check of the data pointer position before we call pskb_may_pull. 4) Reload skb header pointers after calling pskb_may_pull in _decode_session4 as this may change the pointers into the packet. 5) Add a missing statistic counter on inner mode errors. Please pull or let me know if there are problems. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * xfrm: Let the flowcache handle its size by default.Steffen Klassert2015-09-291-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The xfrm flowcache size is limited by the flowcache limit (4096 * number of online cpus) and the xfrm garbage collector threshold (2 * 32768), whatever is reached first. This means that we can hit the garbage collector limit only on systems with more than 16 cpus. On such systems we simply refuse new allocations if we reach the limit, so new flows are dropped. On syslems with 16 or less cpus, we hit the flowcache limit. In this case, we shrink the flow cache instead of refusing new flows. We increase the xfrm garbage collector threshold to INT_MAX to get the same behaviour, independent of the number of cpus. The xfrm garbage collector threshold can still be set below the flowcache limit to reduce the memory usage of the flowcache. Tested-by: Dan Streetman <dan.streetman@canonical.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
* | tcp: use RACK to detect lossesYuchung Cheng2015-10-211-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements the second half of RACK that uses the the most recent transmit time among all delivered packets to detect losses. tcp_rack_mark_lost() is called upon receiving a dubious ACK. It then checks if an not-yet-sacked packet was sent at least "reo_wnd" prior to the sent time of the most recently delivered. If so the packet is deemed lost. The "reo_wnd" reordering window starts with 1msec for fast loss detection and changes to min-RTT/4 when reordering is observed. We found 1msec accommodates well on tiny degree of reordering (<3 pkts) on faster links. We use min-RTT instead of SRTT because reordering is more of a path property but SRTT can be inflated by self-inflicated congestion. The factor of 4 is borrowed from the delayed early retransmit and seems to work reasonably well. Since RACK is still experimental, it is now used as a supplemental loss detection on top of existing algorithms. It is only effective after the fast recovery starts or after the timeout occurs. The fast recovery is still triggered by FACK and/or dupack threshold instead of RACK. We introduce a new sysctl net.ipv4.tcp_recovery for future experiments of loss recoveries. For now RACK can be disabled by setting it to 0. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | tcp: track min RTT using windowed min-filterYuchung Cheng2015-10-211-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kathleen Nichols' algorithm for tracking the minimum RTT of a data stream over some measurement window. It uses constant space and constant time per update. Yet it almost always delivers the same minimum as an implementation that has to keep all the data in the window. The measurement window is tunable via sysctl.net.ipv4.tcp_min_rtt_wlen with a default value of 5 minutes. The algorithm keeps track of the best, 2nd best & 3rd best min values, maintaining an invariant that the measurement time of the n'th best >= n-1'th best. It also makes sure that the three values are widely separated in the time window since that bounds the worse case error when that data is monotonically increasing over the window. Upon getting a new min, we can forget everything earlier because it has no value - the new min is less than everything else in the window by definition and it's the most recent. So we restart fresh on every new min and overwrites the 2nd & 3rd choices. The same property holds for the 2nd & 3rd best. Therefore we have to maintain two invariants to maximize the information in the samples, one on values (1st.v <= 2nd.v <= 3rd.v) and the other on times (now-win <=1st.t <= 2nd.t <= 3rd.t <= now). These invariants determine the structure of the code The RTT input to the windowed filter is the minimum RTT measured from ACK or SACK, or as the last resort from TCP timestamps. The accessor tcp_min_rtt() returns the minimum RTT seen in the window. ~0U indicates it is not available. The minimum is 1usec even if the true RTT is below that. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Revert "ipv4/icmp: redirect messages can use the ingress daddr as source"Paolo Abeni2015-10-141-17/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Revert the commit e2ca690b657f ("ipv4/icmp: redirect messages can use the ingress daddr as source"), which tried to introduce a more suitable behaviour for ICMP redirect messages generated by VRRP routers. However RFC 5798 section 8.1.1 states: The IPv4 source address of an ICMP redirect should be the address that the end-host used when making its next-hop routing decision. while said commit used the generating packet destination address, which do not match the above and in most cases leads to no redirect packets to be generated. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | ipv4/icmp: redirect messages can use the ingress daddr as sourcePaolo Abeni2015-10-131-2/+17
|/ | | | | | | | | | | | | | | | | | | | | | | | | | This patch allows configuring how the source address of ICMP redirect messages is selected; by default the old behaviour is retained, while setting icmp_redirects_use_orig_daddr force the usage of the destination address of the packet that caused the redirect. The new behaviour fits closely the RFC 5798 section 8.1.1, and fix the following scenario: Two machines are set up with VRRP to act as routers out of a subnet, they have IPs x.x.x.1/24 and x.x.x.2/24, with VRRP holding on to x.x.x.254/24. If a host in said subnet needs to get an ICMP redirect from the VRRP router, i.e. to reach a destination behind a different gateway, the source IP in the ICMP redirect is chosen as the primary IP on the interface that the packet arrived at, i.e. x.x.x.1 or x.x.x.2. The host will then ignore said redirect, due to RFC 1122 section 3.2.2.2, and will continue to use the wrong next-op. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* IGMP: Document igmp_link_local_mcast_reportsPhilip Downey2015-08-311-0/+5
| | | | | | | | | | | | | | | | | Document the addition of a new sysctl variable which controls the generation of IGMP reports for link local multicast groups in the 224.0.0.X range. IGMP reports for local multicast groups can now be optionally inhibited by setting the value to zero e.g.: echo 0 > /proc/sys/net/ipv4/igmp_link_local_mcast_reports To retain backwards compatibility the previous behaviour is retained by default on system boot or reverted by setting the value back to non-zero. Signed-off-by: Philip Downey <pdowney@brocade.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: refine pacing rate determinationEric Dumazet2015-08-251-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | When TCP pacing was added back in linux-3.12, we chose to apply a fixed ratio of 200 % against current rate, to allow probing for optimal throughput even during slow start phase, where cwnd can be doubled every other gRTT. At Google, we found it was better applying a different ratio while in Congestion Avoidance phase. This ratio was set to 120 %. We've used the normal tcp_in_slow_start() helper for a while, then tuned the condition to select the conservative ratio as soon as cwnd >= ssthresh/2 : - After cwnd reduction, it is safer to ramp up more slowly, as we approach optimal cwnd. - Initial ramp up (ssthresh == INFINITY) still allows doubling cwnd every other RTT. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Document xfrm4_gc_thresh and xfrm6_gc_threshAlexander Duyck2015-08-121-0/+10
| | | | | | | | | This change adds documentation for xfrm4_gc_thresh and xfrm6_gc_thresh based on the comments in commit eeb1b73378b56 ("xfrm: Increase the garbage collector threshold"). Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
* ipv6: Enable auto flow labels by defaultTom Herbert2015-08-011-1/+1
| | | | | | | | | Initialize auto_flowlabels to one. This enables automatic flow labels, individual socket may disable them using the IPV6_AUTOFLOWLABEL socket option. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: Implement different admin modes for automatic flow labelsTom Herbert2015-08-011-7/+13
| | | | | | | | | | | | | | | Change the meaning of net.ipv6.auto_flowlabels to provide a mode for automatic flow labels generation. There are four modes: 0: flow labels are disabled 1: flow labels are enabled, sockets can opt-out 2: flow labels are allowed, sockets can opt-in 3: flow labels are enabled and enforced, no opt-out for sockets np->autoflowlabel is initialized according to the sysctl value. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net/ipv6: add sysctl option accept_ra_min_hop_limitHangbin Liu2015-07-311-0/+8
| | | | | | | | | | | | | | | | | | | | | | | Commit 6fd99094de2b ("ipv6: Don't reduce hop limit for an interface") disabled accept hop limit from RA if it is smaller than the current hop limit for security stuff. But this behavior kind of break the RFC definition. RFC 4861, 6.3.4. Processing Received Router Advertisements A Router Advertisement field (e.g., Cur Hop Limit, Reachable Time, and Retrans Timer) may contain a value denoting that it is unspecified. In such cases, the parameter should be ignored and the host should continue using whatever value it is already using. If the received Cur Hop Limit value is non-zero, the host SHOULD set its CurHopLimit variable to the received value. So add sysctl option accept_ra_min_hop_limit to let user choose the minimum hop limit value they can accept from RA. And set default to 1 to meet RFC standards. Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Acked-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: sysctl to restrict candidate source addressesErik Kline2015-07-221-0/+7
| | | | | | | | | | | | | Per RFC 6724, section 4, "Candidate Source Addresses": It is RECOMMENDED that the candidate source addresses be the set of unicast addresses assigned to the interface that will be used to send to the destination (the "outgoing" interface). Add a sysctl to enable this behaviour. Signed-off-by: Erik Kline <ek@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: Nonlocal bindTom Herbert2015-07-101-0/+5
| | | | | | | | | | | | | | | | | | | | | | Add support to allow non-local binds similar to how this was done for IPv4. Non-local binds are very useful in emulating the Internet in a box, etc. This add the ip_nonlocal_bind sysctl under ipv6. Testing: Set up nonlocal binding and receive routing on a host, e.g.: ip -6 rule add from ::/0 iif eth0 lookup 200 ip -6 route add local 2001:0:0:1::/64 dev lo proto kernel scope host table 200 sysctl -w net.ipv6.ip_nonlocal_bind=1 Set up routing to 2001:0:0:1::/64 on peer to go to first host ping6 -I 2001:0:0:1::1 peer-address -- to verify Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp/dccp: try to not exhaust ip_local_port_range in connect()Eric Dumazet2015-05-271-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A long standing problem on busy servers is the tiny available TCP port range (/proc/sys/net/ipv4/ip_local_port_range) and the default sequential allocation of source ports in connect() system call. If a host is having a lot of active TCP sessions, chances are very high that all ports are in use by at least one flow, and subsequent bind(0) attempts fail, or have to scan a big portion of space to find a slot. In this patch, I changed the starting point in __inet_hash_connect() so that we try to favor even [1] ports, leaving odd ports for bind() users. We still perform a sequential search, so there is no guarantee, but if connect() targets are very different, end result is we leave more ports available to bind(), and we spread them all over the range, lowering time for both connect() and bind() to find a slot. This strategy only works well if /proc/sys/net/ipv4/ip_local_port_range is even, ie if start/end values have different parity. Therefore, default /proc/sys/net/ipv4/ip_local_port_range was changed to 32768 - 60999 (instead of 32768 - 61000) There is no change on security aspects here, only some poor hashing schemes could be eventually impacted by this change. [1] : The odd/even property depends on ip_local_port_range values parity Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: add rfc3168, section 6.1.1.1. fallbackDaniel Borkmann2015-05-191-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This work as a follow-up of commit f7b3bec6f516 ("net: allow setting ecn via routing table") and adds RFC3168 section 6.1.1.1. fallback for outgoing ECN connections. In other words, this work adds a retry with a non-ECN setup SYN packet, as suggested from the RFC on the first timeout: [...] A host that receives no reply to an ECN-setup SYN within the normal SYN retransmission timeout interval MAY resend the SYN and any subsequent SYN retransmissions with CWR and ECE cleared. [...] Schematic client-side view when assuming the server is in tcp_ecn=2 mode, that is, Linux default since 2009 via commit 255cac91c3c9 ("tcp: extend ECN sysctl to allow server-side only ECN"): 1) Normal ECN-capable path: SYN ECE CWR -----> <----- SYN ACK ECE ACK -----> 2) Path with broken middlebox, when client has fallback: SYN ECE CWR ----X crappy middlebox drops packet (timeout, rtx) SYN -----> <----- SYN ACK ACK -----> In case we would not have the fallback implemented, the middlebox drop point would basically end up as: SYN ECE CWR ----X crappy middlebox drops packet (timeout, rtx) SYN ECE CWR ----X crappy middlebox drops packet (timeout, rtx) SYN ECE CWR ----X crappy middlebox drops packet (timeout, rtx) In any case, it's rather a smaller percentage of sites where there would occur such additional setup latency: it was found in end of 2014 that ~56% of IPv4 and 65% of IPv6 servers of Alexa 1 million list would negotiate ECN (aka tcp_ecn=2 default), 0.42% of these webservers will fail to connect when trying to negotiate with ECN (tcp_ecn=1) due to timeouts, which the fallback would mitigate with a slight latency trade-off. Recent related paper on this topic: Brian Trammell, Mirja Kühlewind, Damiano Boppart, Iain Learmonth, Gorry Fairhurst, and Richard Scheffenegger: "Enabling Internet-Wide Deployment of Explicit Congestion Notification." Proc. PAM 2015, New York. http://ecn.ethz.ch/ecn-pam15.pdf Thus, when net.ipv4.tcp_ecn=1 is being set, the patch will perform RFC3168, section 6.1.1.1. fallback on timeout. For users explicitly not wanting this which can be in DC use case, we add a net.ipv4.tcp_ecn_fallback knob that allows for disabling the fallback. tp->ecn_flags are not being cleared in tcp_ecn_clear_syn() on output, but rather we let tcp_ecn_rcv_synack() take that over on input path in case a SYN ACK ECE was delayed. Thus a spurious SYN retransmission will not prevent ECN being negotiated eventually in that case. Reference: https://www.ietf.org/proceedings/92/slides/slides-92-iccrg-1.pdf Reference: https://www.ietf.org/proceedings/89/slides/slides-89-tsvarea-1.pdf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Mirja Kühlewind <mirja.kuehlewind@tik.ee.ethz.ch> Signed-off-by: Brian Trammell <trammell@tik.ee.ethz.ch> Cc: Eric Dumazet <edumazet@google.com> Cc: Dave That <dave.taht@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: Flow label state rangesTom Herbert2015-05-041-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch divides the IPv6 flow label space into two ranges: 0-7ffff is reserved for flow label manager, 80000-fffff will be used for creating auto flow labels (per RFC6438). This only affects how labels are set on transmit, it does not affect receive. This range split can be disbaled by systcl. Background: IPv6 flow labels have been an unmitigated disappointment thus far in the lifetime of IPv6. Support in HW devices to use them for ECMP is lacking, and OSes don't turn them on by default. If we had these we could get much better hashing in IPv6 networks without resorting to DPI, possibly eliminating some of the motivations to to define new encaps in UDP just for getting ECMP. Unfortunately, the initial specfications of IPv6 did not clarify how they are to be used. There has always been a vague concept that these can be used for ECMP, flow hashing, etc. and we do now have a good standard how to this in RFC6438. The problem is that flow labels can be either stateful or stateless (as in RFC6438), and we are presented with the possibility that a stateless label may collide with a stateful one. Attempts to split the flow label space were rejected in IETF. When we added support in Linux for RFC6438, we could not turn on flow labels by default due to this conflict. This patch splits the flow label space and should give us a path to enabling auto flow labels by default for all IPv6 packets. This is an API change so we need to consider compatibility with existing deployment. The stateful range is chosen to be the lower values in hopes that most uses would have chosen small numbers. Once we resolve the stateless/stateful issue, we can proceed to look at enabling RFC6438 flow labels by default (starting with scaled testing). Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv6: add documentation for stable_secret, idgen_delay and idgen_retries knobsHannes Frederic Sowa2015-03-241-0/+25
| | | | | | | | | Cc: Erik Kline <ek@google.com> Cc: Fernando Gont <fgont@si6networks.com> Cc: Lorenzo Colitti <lorenzo@google.com> Cc: YOSHIFUJI Hideaki/吉藤英明 <hideaki.yoshifuji@miraclelinux.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: neighbour: Document {mcast, ucast}_solicit, mcast_resolicit.YOSHIFUJI Hideaki/吉藤英明2015-03-211-1/+13
| | | | | Signed-off-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipv4: Documenting two sysctls for tcp PMTU probeFan Du2015-03-061-0/+10
| | | | | | | | | Namely tcp_probe_interval to control how often to restart a probe. And tcp_probe_threshold to control when stop the probing in respect to the width of search range in bytes Signed-off-by: Fan Du <fan.du@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacksNeal Cardwell2015-02-081-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Helpers for mitigating ACK loops by rate-limiting dupacks sent in response to incoming out-of-window packets. This patch includes: - rate-limiting logic - sysctl to control how often we allow dupacks to out-of-window packets - SNMP counter for cases where we rate-limited our dupack sending The rate-limiting logic in this patch decides to not send dupacks in response to out-of-window segments if (a) they are SYNs or pure ACKs and (b) the remote endpoint is sending them faster than the configured rate limit. We rate-limit our responses rather than blocking them entirely or resetting the connection, because legitimate connections can rely on dupacks in response to some out-of-window segments. For example, zero window probes are typically sent with a sequence number that is below the current window, and ZWPs thus expect to thus elicit a dupack in response. We allow dupacks in response to TCP segments with data, because these may be spurious retransmissions for which the remote endpoint wants to receive DSACKs. This is safe because segments with data can't realistically be part of ACK loops, which by their nature consist of each side sending pure/data-less ACKs to each other. The dupack interval is controlled by a new sysctl knob, tcp_invalid_ratelimit, given in milliseconds, in case an administrator needs to dial this upward in the face of a high-rate DoS attack. The name and units are chosen to be analogous to the existing analogous knob for ICMP, icmp_ratelimit. The default value for tcp_invalid_ratelimit is 500ms, which allows at most one such dupack per 500ms. This is chosen to be 2x faster than the 1-second minimum RTO interval allowed by RFC 6298 (section 2, rule 2.4). We allow the extra 2x factor because network delay variations can cause packets sent at 1 second intervals to be compressed and arrive much closer. Reported-by: Avery Fay <avery@mixpanel.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: ipv6: Add sysctl entry to disable MTU updates from RAHarout Hedeshian2015-01-251-0/+7
| | | | | | | | | | | | | The kernel forcefully applies MTU values received in router advertisements provided the new MTU is less than the current. This behavior is undesirable when the user space is managing the MTU. Instead a sysctl flag 'accept_ra_mtu' is introduced such that the user space can control whether or not RA provided MTU updates should be applied. The default behavior is unchanged; user space must explicitly set this flag to 0 for RA MTUs to be ignored. Signed-off-by: Harout Hedeshian <harouth@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* update ip-sysctl.txt documentation (v2)Ani Sinha2015-01-121-0/+2
| | | | | | | | Update documentation to reflect the fact that /proc/sys/net/ipv4/route/max_size is no longer used for ipv4. Signed-off-by: Ani Sinha <ani@arista.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2014-11-071-0/+14
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| * net: Add missing descriptions for fwmark_reflect for ipv4 and ipv6.Loganaden Velvindron2014-11-051-0/+14
| | | | | | | | | | | | | | | | It was initially sent by Lorenzo Colitti, but was subsequently lost in the final diff he submitted. Signed-off-by: Loganaden Velvindron <logan@elandsys.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net: ipv6: Add a sysctl to make optimistic addresses useful candidatesErik Kline2014-10-291-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a sysctl that causes an interface's optimistic addresses to be considered equivalent to other non-deprecated addresses for source address selection purposes. Preferred addresses will still take precedence over optimistic addresses, subject to other ranking in the source address selection algorithm. This is useful where different interfaces are connected to different networks from different ISPs (e.g., a cell network and a home wifi network). The current behaviour complies with RFC 3484/6724, and it makes sense if the host has only one interface, or has multiple interfaces on the same network (same or cooperating administrative domain(s), but not in the multiple distinct networks case. For example, if a mobile device has an IPv6 address on an LTE network and then connects to IPv6-enabled wifi, while the wifi IPv6 address is undergoing DAD, IPv6 connections will try use the wifi default route with the LTE IPv6 address, and will get stuck until they time out. Also, because optimistic nodes can receive frames, issue an RTM_NEWADDR as soon as DAD starts (with the IFA_F_OPTIMSTIC flag appropriately set). A second RTM_NEWADDR is sent if DAD completes (the address flags have changed), otherwise an RTM_DELADDR is sent. Also: add an entry in ip-sysctl.txt for optimistic_dad. Signed-off-by: Erik Kline <ek@google.com> Acked-by: Lorenzo Colitti <lorenzo@google.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* | tcp: allow for bigger reordering levelEric Dumazet2014-10-291-1/+9
|/ | | | | | | | | | | | | | | | | | | While testing upcoming Yaogong patch (converting out of order queue into an RB tree), I hit the max reordering level of linux TCP stack. Reordering level was limited to 127 for no good reason, and some network setups [1] can easily reach this limit and get limited throughput. Allow a new max limit of 300, and add a sysctl to allow admins to even allow bigger (or lower) values if needed. [1] Aggregation of links, per packet load balancing, fabrics not doing deep packet inspections, alternative TCP congestion modules... Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Yaogong Wang <wygivan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds2014-10-091-8/+32
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking updates from David Miller: "Most notable changes in here: 1) By far the biggest accomplishment, thanks to a large range of contributors, is the addition of multi-send for transmit. This is the result of discussions back in Chicago, and the hard work of several individuals. Now, when the ->ndo_start_xmit() method of a driver sees skb->xmit_more as true, it can choose to defer the doorbell telling the driver to start processing the new TX queue entires. skb->xmit_more means that the generic networking is guaranteed to call the driver immediately with another SKB to send. There is logic added to the qdisc layer to dequeue multiple packets at a time, and the handling mis-predicted offloads in software is now done with no locks held. Finally, pktgen is extended to have a "burst" parameter that can be used to test a multi-send implementation. Several drivers have xmit_more support: i40e, igb, ixgbe, mlx4, virtio_net Adding support is almost trivial, so export more drivers to support this optimization soon. I want to thank, in no particular or implied order, Jesper Dangaard Brouer, Eric Dumazet, Alexander Duyck, Tom Herbert, Jamal Hadi Salim, John Fastabend, Florian Westphal, Daniel Borkmann, David Tat, Hannes Frederic Sowa, and Rusty Russell. 2) PTP and timestamping support in bnx2x, from Michal Kalderon. 3) Allow adjusting the rx_copybreak threshold for a driver via ethtool, and add rx_copybreak support to enic driver. From Govindarajulu Varadarajan. 4) Significant enhancements to the generic PHY layer and the bcm7xxx driver in particular (EEE support, auto power down, etc.) from Florian Fainelli. 5) Allow raw buffers to be used for flow dissection, allowing drivers to determine the optimal "linear pull" size for devices that DMA into pools of pages. The objective is to get exactly the necessary amount of headers into the linear SKB area pre-pulled, but no more. The new interface drivers use is eth_get_headlen(). From WANG Cong, with driver conversions (several had their own by-hand duplicated implementations) by Alexander Duyck and Eric Dumazet. 6) Support checksumming more smoothly and efficiently for encapsulations, and add "foo over UDP" facility. From Tom Herbert. 7) Add Broadcom SF2 switch driver to DSA layer, from Florian Fainelli. 8) eBPF now can load programs via a system call and has an extensive testsuite. Alexei Starovoitov and Daniel Borkmann. 9) Major overhaul of the packet scheduler to use RCU in several major areas such as the classifiers and rate estimators. From John Fastabend. 10) Add driver for Intel FM10000 Ethernet Switch, from Alexander Duyck. 11) Rearrange TCP_SKB_CB() to reduce cache line misses, from Eric Dumazet. 12) Add Datacenter TCP congestion control algorithm support, From Florian Westphal. 13) Reorganize sk_buff so that __copy_skb_header() is significantly faster. From Eric Dumazet" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1558 commits) netlabel: directly return netlbl_unlabel_genl_init() net: add netdev_txq_bql_{enqueue, complete}_prefetchw() helpers net: description of dma_cookie cause make xmldocs warning cxgb4: clean up a type issue cxgb4: potential shift wrapping bug i40e: skb->xmit_more support net: fs_enet: Add NAPI TX net: fs_enet: Remove non NAPI RX r8169:add support for RTL8168EP net_sched: copy exts->type in tcf_exts_change() wimax: convert printk to pr_foo() af_unix: remove 0 assignment on static ipv6: Do not warn for informational ICMP messages, regardless of type. Update Intel Ethernet Driver maintainers list bridge: Save frag_max_size between PRE_ROUTING and POST_ROUTING tipc: fix bug in multicast congestion handling net: better IFF_XMIT_DST_RELEASE support net/mlx4_en: remove NETDEV_TX_BUSY 3c59x: fix bad split of cpu_to_le32(pci_map_single()) net: bcmgenet: fix Tx ring priority programming ...
| * icmp: add a global rate limitationEric Dumazet2014-09-231-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current ICMP rate limiting uses inetpeer cache, which is an RBL tree protected by a lock, meaning that hosts can be stuck hard if all cpus want to check ICMP limits. When say a DNS or NTP server process is restarted, inetpeer tree grows quick and machine comes to its knees. iptables can not help because the bottleneck happens before ICMP messages are even cooked and sent. This patch adds a new global limitation, using a token bucket filter, controlled by two new sysctl : icmp_msgs_per_sec - INTEGER Limit maximal number of ICMP packets sent per second from this host. Only messages whose type matches icmp_ratemask are controlled by this limit. Default: 1000 icmp_msgs_burst - INTEGER icmp_msgs_per_sec controls number of ICMP packets sent per second, while icmp_msgs_burst controls the burst size of these packets. Default: 50 Note that if we really want to send millions of ICMP messages per second, we might extend idea and infra added in commit 04ca6973f7c1a ("ip: make IP identifiers less predictable") : add a token bucket in the ip_idents hash and no longer rely on inetpeer. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * Revert "ipv4: Clarify in docs that accept_local requires rp_filter."Sébastien Barré2014-09-121-8/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit c801e3cc1925 ("ipv4: Clarify in docs that accept_local requires rp_filter."). It is not needed anymore since commit 1dced6a85482 ("ipv4: Restore accept_local behaviour in fib_validate_source()"). Suggested-by: Julian Anastasov <ja@ssi.bg> Cc: Gregory Detal <gregory.detal@uclouvain.be> Cc: Christoph Paasch <christoph.paasch@uclouvain.be> Cc: Hannes Frederic Sowa <hannes@redhat.com> Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Signed-off-by: Sébastien Barré <sebastien.barre@uclouvain.be> Signed-off-by: David S. Miller <davem@davemloft.net>
| * ipv4: implement igmp_qrv sysctl to tune igmp robustness variableHannes Frederic Sowa2014-09-051-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As in IPv6 people might increase the igmp query robustness variable to make sure unsolicited state change reports aren't lost on the network. Add and document this new knob to igmp code. RFCs allow tuning this parameter back to first IGMP RFC, so we also use this setting for all counters, including source specific multicast. Also take over sysctl value when upping the interface and don't reuse the last one seen on the interface. Cc: Flavio Leitner <fbl@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Flavio Leitner <fbl@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * ipv6: add sysctl_mld_qrv to configure query robustness variableHannes Frederic Sowa2014-09-051-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a new sysctl_mld_qrv knob to configure the mldv1/v2 query robustness variable. It specifies how many retransmit of unsolicited mld retransmit should happen. Admins might want to tune this on lossy links. Also reset mld state on interface down/up, so we pick up new sysctl settings during interface up event. IPv6 certification requests this knob to be available. I didn't make this knob netns specific, as it is mostly a setting in a physical environment and should be per host. Cc: Flavio Leitner <fbl@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Flavio Leitner <fbl@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * neigh: document gc_thresh2stephen hemminger2014-08-261-0/+6
| | | | | | | | | | | | | | Missing documentation for gc_thresh2 sysctl. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge tag 'dmaengine-3.17' of ↵Linus Torvalds2014-10-081-6/+0
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine Pull dmaengine updates from Dan Williams: "Even though this has fixes marked for -stable, given the size and the needed conflict resolutions this is 3.18-rc1/merge-window material. These patches have been languishing in my tree for a long while. The fact that I do not have the time to do proper/prompt maintenance of this tree is a primary factor in the decision to step down as dmaengine maintainer. That and the fact that the bulk of drivers/dma/ activity is going through Vinod these days. The net_dma removal has not been in -next. It has developed simple conflicts against mainline and net-next (for-3.18). Continuing thanks to Vinod for staying on top of drivers/dma/. Summary: 1/ Step down as dmaengine maintainer see commit 08223d80df38 "dmaengine maintainer update" 2/ Removal of net_dma, as it has been marked 'broken' since 3.13 (commit 77873803363c "net_dma: mark broken"), without reports of performance regression. 3/ Miscellaneous fixes" * tag 'dmaengine-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine: net: make tcp_cleanup_rbuf private net_dma: revert 'copied_early' net_dma: simple removal dmaengine maintainer update dmatest: prevent memory leakage on error path in thread ioat: Use time_before_jiffies() dmaengine: fix xor sources continuation dma: mv_xor: Rename __mv_xor_slot_cleanup() to mv_xor_slot_cleanup() dma: mv_xor: Remove all callers of mv_xor_slot_cleanup() dma: mv_xor: Remove unneeded mv_xor_clean_completed_slots() call ioat: Use pci_enable_msix_exact() instead of pci_enable_msix() drivers: dma: Include appropriate header file in dca.c drivers: dma: Mark functions as static in dma_v3.c dma: mv_xor: Add DMA API error checks ioat/dca: Use dev_is_pci() to check whether it is pci device
| * net_dma: simple removalDan Williams2014-09-281-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Per commit "77873803363c net_dma: mark broken" net_dma is no longer used and there is no plan to fix it. This is the mechanical removal of bits in CONFIG_NET_DMA ifdef guards. Reverting the remainder of the net_dma induced changes is deferred to subsequent patches. Marked for stable due to Roman's report of a memory leak in dma_pin_iovec_pages(): https://lkml.org/lkml/2014/9/3/177 Cc: Dave Jiang <dave.jiang@intel.com> Cc: Vinod Koul <vinod.koul@intel.com> Cc: David Whipple <whipple@securedatainnovations.ch> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: <stable@vger.kernel.org> Reported-by: Roman Gushchin <klamm@yandex-team.ru> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | inet: frag: set limits and make init_net's high_thresh limit globalNikolay Aleksandrov2014-07-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes init_net's high_thresh limit to be the maximum for all namespaces, thus introducing a global memory limit threshold equal to the sum of the individual high_thresh limits which are capped. It also introduces some sane minimums for low_thresh as it shouldn't be able to drop below 0 (or > high_thresh in the unsigned case), and overall low_thresh should not ever be above high_thresh, so we make the following relations for a namespace: init_net: high_thresh - max(not capped), min(init_net low_thresh) low_thresh - max(init_net high_thresh), min (0) all other namespaces: high_thresh = max(init_net high_thresh), min(namespace's low_thresh) low_thresh = max(namespace's high_thresh), min(0) The major issue with having low_thresh > high_thresh is that we'll schedule eviction but never evict anything and thus rely only on the timers. Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | inet: frag: remove periodic secret rebuild timerFlorian Westphal2014-07-281-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | merge functionality into the eviction workqueue. Instead of rebuilding every n seconds, take advantage of the upper hash chain length limit. If we hit it, mark table for rebuild and schedule workqueue. To prevent frequent rebuilds when we're completely overloaded, don't rebuild more than once every 5 seconds. ipfrag_secret_interval sysctl is now obsolete and has been marked as deprecated, it still can be changed so scripts won't be broken but it won't have any effect. A comment is left above each unused secret_timer variable to avoid confusion. Joint work with Nikolay Aleksandrov. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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