- 24 Jun, 2021 10 commits
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Steen Hegelund authored
This adds Sparx5 VLAN support. Sparx5 has more VLAN features than provided here, but these will be added in later series. For now we only add the basic L2 features. Signed-off-by:
Steen Hegelund <steen.hegelund@microchip.com> Signed-off-by:
Bjarni Jonasson <bjarni.jonasson@microchip.com> Signed-off-by:
Lars Povlsen <lars.povlsen@microchip.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Steen Hegelund authored
This adds the Sparx5 MAC tables: listening for MAC table updates and updating on request. Signed-off-by:
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Steen Hegelund authored
This add configuration of the Sparx5 port module instances. Sparx5 has in total 65 logical ports (denoted D0 to D64) and 33 physical SerDes connections (S0 to S32). The 65th port (D64) is fixed allocated to SerDes0 (S0). The remaining 64 ports can in various multiplexing scenarios be connected to the remaining 32 SerDes using QSGMII, or USGMII or USXGMII extenders. 32 of the ports can have a 1:1 mapping to the 32 SerDes. Some additional ports (D65 to D69) are internal to the device and do not connect to port modules or SerDes macros. For example, internal ports are used for frame injection and extraction to the CPU queues. The 65 logical ports are split up into the following blocks. - 13 x 5G ports (D0-D11, D64) - 32 x 2G5 ports (D16-D47) - 12 x 10G ports (D12-D15, D48-D55) - 8 x 25G ports (D56-D63) Each logical port supports different line speeds, and depending on the speeds supported, different port modules (MAC+PCS) are needed. A port supporting 5 Gbps, 10 Gbps, or 25 Gbps as maximum line speed, will have a DEV5G, DEV10G, or DEV25G module to support the 5 Gbps, 10 Gbps (incl 5 Gbps), or 25 Gbps (including 10 Gbps and 5 Gbps) speeds. As well as, it will have a shadow DEV2G5 port module to support the lower speeds (10/100/1000/2500Mbps). When a port needs to operate at lower speed and the shadow DEV2G5 needs to be connected to its corresponding SerDes Not all interface modes are supported in this series, but will be added at a later stage. Signed-off-by:
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Steen Hegelund authored
This patch adds netdevs and phylink support for the ports in the switch. It also adds register based injection and extraction for these ports. Frame DMA support for injection and extraction will be added in a later series. Signed-off-by:
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Steen Hegelund authored
This adds the Sparx5 basic SwitchDev driver framework with IO range mapping, switch device detection and core clock configuration. Support for ports, phylink, netdev, mactable etc. are in the following patches. Signed-off-by:
Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by:
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Steen Hegelund authored
Document the Sparx5 switch device driver bindings Signed-off-by:
Rob Herring <robh@kernel.org> Signed-off-by:
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Marcin Wojtas authored
The fallback case of fwnode_mdbiobus_register() (relevant for !CONFIG_FWNODE_MDIO) was defined with wrong argument name, causing a compilation error. Fix that. Signed-off-by:
Marcin Wojtas <mw@semihalf.com> Reviewed-by:
Andrew Lunn <andrew@lunn.ch> Signed-off-by:
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Jakub Kicinski authored
Dave observed number of machines hitting OOM on the UDP send path. The workload seems to be sending large UDP packets over loopback. Since loopback has MTU of 64k kernel will try to allocate an skb with up to 64k of head space. This has a good chance of failing under memory pressure. What's worse if the message length is <32k the allocation may trigger an OOM killer. This is entirely avoidable, we can use an skb with page frags. af_unix solves a similar problem by limiting the head length to SKB_MAX_ALLOC. This seems like a good and simple approach. It means that UDP messages > 16kB will now use fragments if underlying device supports SG, if extra allocator pressure causes regressions in real workloads we can switch to trying the large allocation first and falling back. v4: pre-calculate all the additions to alloclen so we can be sure it won't go over order-2 Reported-by:Dave Jones <dsj@fb.com> Signed-off-by:
Jakub Kicinski <kuba@kernel.org> Signed-off-by:
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Lorenz Bauer authored
Make sure that SO_NETNS_COOKIE returns a non-zero value, and that sockets from different namespaces have a distinct cookie value. Signed-off-by:
Lorenz Bauer <lmb@cloudflare.com> Signed-off-by:
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Martynas Pumputis authored
It's getting more common to run nested container environments for testing cloud software. One of such examples is Kind [1] which runs a Kubernetes cluster in Docker containers on a single host. Each container acts as a Kubernetes node, and thus can run any Pod (aka container) inside the former. This approach simplifies testing a lot, as it eliminates complicated VM setups. Unfortunately, such a setup breaks some functionality when cgroupv2 BPF programs are used for load-balancing. The load-balancer BPF program needs to detect whether a request originates from the host netns or a container netns in order to allow some access, e.g. to a service via a loopback IP address. Typically, the programs detect this by comparing netns cookies with the one of the init ns via a call to bpf_get_netns_cookie(NULL). However, in nested environments the latter cannot be used given the Kubernetes node's netns is outside the init ns. To fix this, we need to pass the Kubernetes node netns cookie to the program in a different way: by extending getsockopt() with a SO_NETNS_COOKIE option, the orchestrator which runs in the Kubernetes node netns can retrieve the cookie and pass it to the program instead. Thus, this is following up on Eric's commit 3d368ab8 ("net: initialize net->net_cookie at netns setup") to allow retrieval via SO_NETNS_COOKIE. This is also in line in how we retrieve socket cookie via SO_COOKIE. [1] https://kind.sigs.k8s.io/Signed-off-by:
Martynas Pumputis <m@lambda.lt> Cc: Eric Dumazet <edumazet@google.com> Reviewed-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
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- 23 Jun, 2021 15 commits
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David S. Miller authored
Dmytro Linkin says: ==================== Fixes for devlink rate objects API Patch #1 fixes not decreased refcount of parent node for destroyed leaf object. Patch #2 fixes incorect eswitch mode check. Patch #3 protects list traversing with a lock. ==================== Signed-off-by: -
Dmytro Linkin authored
Devlink eswitch set command doesn't hold devlink->lock, which makes possible race condition between rate list traversing and others devlink rate KAPI calls, like devlink_rate_nodes_destroy(). Hold devlink lock while traversing the list. Fixes: a8ecb93e ("devlink: Introduce rate nodes") Signed-off-by:
Dmytro Linkin <dlinkin@nvidia.com> Reviewed-by:
Parav Pandit <parav@nvidia.com> Reviewed-by:
Jiri Pirko <jiri@nvidia.com> Signed-off-by:
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Dmytro Linkin authored
When eswitch is disabled, querying its current mode results in error. Due to this when trying to set the eswitch mode for mlx5 devices, it fails to set the eswitch switchdev mode. Hence remove such check. Fixes: a8ecb93e ("devlink: Introduce rate nodes") Signed-off-by:
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Dmytro Linkin authored
Port functions, like SFs, can be deleted by the user when its leaf rate object has parent node. In such case node refcnt won't be decreased which blocks the node from deletion later. Do simple refcnt decrease, since driver in cleanup stage. This: 1) assumes that driver took proper internal parent unset action; 2) allows to avoid nested callbacks call and deadlock. Fixes: d7555984 ("devlink: Allow setting parent node of rate objects") Signed-off-by:
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Xianting Tian authored
virtio_find_vqs_ctx() is defined but never be called currently, it is the right place to use it. Signed-off-by:
Xianting Tian <xianting.tian@linux.alibaba.com> Reviewed-by:
Stefano Garzarella <sgarzare@redhat.com> Signed-off-by:
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Kuniyuki Iwashima authored
The commit d26b698d ("net/tls: add skeleton of MIB statistics") introduced __TLS_DEC_STATS(), but it is not used and __SNMP_DEC_STATS() is not defined also. Let's remove it. Signed-off-by:
Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by:
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Kuniyuki Iwashima authored
This commit adds two stats for the socket migration feature to evaluate the effectiveness: LINUX_MIB_TCPMIGRATEREQ(SUCCESS|FAILURE). If the migration fails because of the own_req race in receiving ACK and sending SYN+ACK paths, we do not increment the failure stat. Then another CPU is responsible for the req. Link: https://lore.kernel.org/bpf/CAK6E8=cgFKuGecTzSCSQ8z3YJ_163C0uwO9yRvfDSE7vOe9mJA@mail.gmail.com/Suggested-by:
Yuchung Cheng <ycheng@google.com> Signed-off-by:
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David Wilder authored
TCP checksums on received packets may be set to NULL by the sender if CSO is enabled. The hypervisor flags these packets as check-sum-ok and the skb is then flagged CHECKSUM_UNNECESSARY. If these packets are then forwarded the sender will not request CSO due to the CHECKSUM_UNNECESSARY flag. The result is a TCP packet sent with a bad checksum. This change sets up CHECKSUM_PARTIAL on these packets causing the sender to correctly request CSUM offload. Signed-off-by:
David Wilder <dwilder@us.ibm.com> Reviewed-by:
Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com> Tested-by:
Cristobal Forno <cforno12@linux.ibm.com> Signed-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linuxDavid S. Miller authored
Saeed Mahameed says: ==================== mlx5-net-next-2021-06-22 1) Various minor cleanups and fixes from net-next branch 2) Optimize mlx5 feature check on tx and a fix to allow Vxlan with Ipsec offloads ==================== Signed-off-by: -
git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-nextDavid S. Miller authored
Pablo Neira Ayuso says: ==================== Netfilter updates for net-next The following patchset contains Netfilter updates for net-next: 1) Skip non-SCTP packets in the new SCTP chunk support for nft_exthdr, from Phil Sutter. 2) Simplify TCP option sanity check for TCP packets, also from Phil. 3) Add a new expression to store when the rule has been used last time. 4) Pass the hook state object to log function, from Florian Westphal. 5) Document the new sysctl knobs to tune the flowtable timeouts, from Oz Shlomo. 6) Fix snprintf error check in the new nfnetlink_hook infrastructure, from Dan Carpenter. ==================== Signed-off-by: -
Andrea Righi authored
According to a comment in commit 99513cfa ("selftest: Fixes for icmp_redirect test") the test "IPv6: mtu exception plus redirect" is expected to fail, because of a bug in the IPv6 logic that hasn't been fixed yet apparently. We should probably consider this failure as an "expected failure", therefore change the script to return XFAIL for that particular test and also report the total amount of expected failures at the end of the run. Signed-off-by:
Andrea Righi <andrea.righi@canonical.com> Signed-off-by:
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David S. Miller authored
Yunsheng Lin says: ==================== Some optimization for lockless qdisc Patch 1: remove unnecessary seqcount operation. Patch 2: implement TCQ_F_CAN_BYPASS. Patch 3: remove qdisc->empty. Performance data for pktgen in queue_xmit mode + dummy netdev with pfifo_fast: threads unpatched patched delta 1 2.60Mpps 3.21Mpps +23% 2 3.84Mpps 5.56Mpps +44% 4 5.52Mpps 5.58Mpps +1% 8 2.77Mpps 2.76Mpps -0.3% 16 2.24Mpps 2.23Mpps -0.4% Performance for IP forward testing: 1.05Mpps increases to 1.16Mpps, about 10% improvement. V3: Add 'Acked-by' from Jakub and 'Tested-by' from Vladimir, and resend based on latest net-next. V2: Adjust the comment and commit log according to discussion in V1. V1: Drop RFC tag, add nolock_qdisc_is_empty() and do the qdisc empty checking without the protection of qdisc->seqlock to aviod doing unnecessary spin_trylock() for contention case. RFC v4: Use STATE_MISSED and STATE_DRAINING to indicate non-empty qdisc, and add patch 1 and 3. ==================== Signed-off-by: -
Yunsheng Lin authored
As MISSED and DRAINING state are used to indicate a non-empty qdisc, qdisc->empty is not longer needed, so remove it. Acked-by:
Yunsheng Lin <linyunsheng@huawei.com> Signed-off-by:
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Yunsheng Lin authored
Currently pfifo_fast has both TCQ_F_CAN_BYPASS and TCQ_F_NOLOCK flag set, but queue discipline by-pass does not work for lockless qdisc because skb is always enqueued to qdisc even when the qdisc is empty, see __dev_xmit_skb(). This patch calls sch_direct_xmit() to transmit the skb directly to the driver for empty lockless qdisc, which aviod enqueuing and dequeuing operation. As qdisc->empty is not reliable to indicate a empty qdisc because there is a time window between enqueuing and setting qdisc->empty. So we use the MISSED state added in commit a90c57f2 ("net: sched: fix packet stuck problem for lockless qdisc"), which indicate there is lock contention, suggesting that it is better not to do the qdisc bypass in order to avoid packet out of order problem. In order to make MISSED state reliable to indicate a empty qdisc, we need to ensure that testing and clearing of MISSED state is within the protection of qdisc->seqlock, only setting MISSED state can be done without the protection of qdisc->seqlock. A MISSED state testing is added without the protection of qdisc->seqlock to aviod doing unnecessary spin_trylock() for contention case. As the enqueuing is not within the protection of qdisc->seqlock, there is still a potential data race as mentioned by Jakub [1]: thread1 thread2 thread3 qdisc_run_begin() # true qdisc_run_begin(q) set(MISSED) pfifo_fast_dequeue clear(MISSED) # recheck the queue qdisc_run_end() enqueue skb1 qdisc empty # true qdisc_run_begin() # true sch_direct_xmit() # skb2 qdisc_run_begin() set(MISSED) When above happens, skb1 enqueued by thread2 is transmited after skb2 is transmited by thread3 because MISSED state setting and enqueuing is not under the qdisc->seqlock. If qdisc bypass is disabled, skb1 has better chance to be transmited quicker than skb2. This patch does not take care of the above data race, because we view this as similar as below: Even at the same time CPU1 and CPU2 write the skb to two socket which both heading to the same qdisc, there is no guarantee that which skb will hit the qdisc first, because there is a lot of factor like interrupt/softirq/cache miss/scheduling afffecting that. There are below cases that need special handling: 1. When MISSED state is cleared before another round of dequeuing in pfifo_fast_dequeue(), and __qdisc_run() might not be able to dequeue all skb in one round and call __netif_schedule(), which might result in a non-empty qdisc without MISSED set. In order to avoid this, the MISSED state is set for lockless qdisc and __netif_schedule() will be called at the end of qdisc_run_end. 2. The MISSED state also need to be set for lockless qdisc instead of calling __netif_schedule() directly when requeuing a skb for a similar reason. 3. For netdev queue stopped case, the MISSED case need clearing while the netdev queue is stopped, otherwise there may be unnecessary __netif_schedule() calling. So a new DRAINING state is added to indicate this case, which also indicate a non-empty qdisc. 4. As there is already netif_xmit_frozen_or_stopped() checking in dequeue_skb() and sch_direct_xmit(), which are both within the protection of qdisc->seqlock, but the same checking in __dev_xmit_skb() is without the protection, which might cause empty indication of a lockless qdisc to be not reliable. So remove the checking in __dev_xmit_skb(), and the checking in the protection of qdisc->seqlock seems enough to avoid the cpu consumption problem for netdev queue stopped case. 1. https://lkml.org/lkml/2021/5/29/215Acked-by:
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Yunsheng Lin authored
qdisc->running seqcount operation is mainly used to do heuristic locking on q->busylock for locked qdisc, see qdisc_is_running() and __dev_xmit_skb(). So avoid doing seqcount operation for qdisc with TCQ_F_NOLOCK flag. Acked-by:
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- 22 Jun, 2021 15 commits
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Huy Nguyen authored
The packet is VXLAN packet over IPsec transport mode tunnel which has the following format: [IP1 | ESP | UDP | VXLAN | IP2 | TCP] NVIDIA ConnectX card cannot do checksum offload for two L4 headers. The solution is using the checksum partial offload similar to VXLAN | TCP packet. Hardware calculates IP1, IP2 and TCP checksums and software calculates UDP checksum. However, unlike VXLAN | TCP case, IPsec's mlx5 driver cannot access the inner plaintext IP protocol type. Therefore, inner_ipproto is added in the sec_path structure to provide this information. Also, utilize the skb's csum_start to program L4 inner checksum offset. While at it, remove the call to mlx5e_set_eseg_swp and setup software parser fields directly in mlx5e_ipsec_set_swp. mlx5e_set_eseg_swp is not needed as the two features (GENEVE and IPsec) are different and adding this sharing layer creates unnecessary complexity and affect performance. For the case VXLAN packet over IPsec tunnel mode tunnel, checksum offload is disabled because the hardware does not support checksum offload for three L3 (IP) headers. Signed-off-by:
Raed Salem <raeds@nvidia.com> Signed-off-by:
Huy Nguyen <huyn@nvidia.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by:
Saeed Mahameed <saeedm@nvidia.com>
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Huy Nguyen authored
The inner_ipproto saves the inner IP protocol of the plain text packet. This allows vendor's IPsec feature making offload decision at skb's features_check and configuring hardware at ndo_start_xmit. For example, ConnectX6-DX IPsec device needs the plaintext's IP protocol to support partial checksum offload on VXLAN/GENEVE packet over IPsec transport mode tunnel. Signed-off-by:
Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by:
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Huy Nguyen authored
mlx5e_ipsec_feature_check belongs to mlx5e_tunnel_features_check. Also, IPsec is not the default configuration so it should be checked at the end instead of the beginning of mlx5e_features_check. Signed-off-by:
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caihuoqing authored
remove "default n" and "No" is default Signed-off-by:
caihuoqing <caihuoqing@baidu.com> Signed-off-by:
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Colin Ian King authored
There is a spelling mistake in a mlx5_core_err error message. Fix it. Signed-off-by:
Colin Ian King <colin.king@canonical.com> Signed-off-by:
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Nathan Chancellor authored
When CONFIG_CPUMASK_OFFSTACK is unset, cpumask_var_t is not a pointer but a single element array, meaning its address in a structure cannot be NULL as long as it is not the first element, which it is not. This results in a clang warning: drivers/net/ethernet/mellanox/mlx5/core/eq.c:715:14: warning: address of array 'param->affinity' will always evaluate to 'true' [-Wpointer-bool-conversion] if (!param->affinity) ~~~~~~~~^~~~~~~~ 1 warning generated. The helper cpumask_available was added in commit f7e30f01 ("cpumask: Add helper cpumask_available()") to handle situations like this so use it to keep the meaning of the code the same while resolving the warning. Fixes: e4e3f24b ("net/mlx5: Provide cpumask at EQ creation phase") Link: https://github.com/ClangBuiltLinux/linux/issues/1400Signed-off-by:Nathan Chancellor <nathan@kernel.org> Reviewed-by:
Leon Romanovsky <leonro@nvidia.com> Signed-off-by:
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Jiapeng Chong authored
The error code is missing in this code scenario, add the error code '-ENOMEM' to the return value 'err'. Eliminate the follow smatch warning: drivers/net/ethernet/mellanox/mlx5/core/fs_core.c:2973 mlx5_init_fs() warn: missing error code 'err'. Reported-by:
Abaci Robot <abaci@linux.alibaba.com> Fixes: 4a98544d ("net/mlx5: Move chains ft pool to be used by all firmware steering"). Signed-off-by:
Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Signed-off-by:
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David S. Miller authored
Mat Martineau says: ==================== mptcp: Connection-time 'C' flag and two fixes Here are six more patches from the MPTCP tree. Most of them add support for the 'C' flag in the MPTCP connection-time option headers. This flag affects how the initial address and port are treated by each peer. Normally one peer may send MP_JOIN requests to the remote address and port that were used when initiating the MPTCP connection. The 'C' bit indicates that MP_JOINs should only be sent to remote addresses that have been advertised with ADD_ADDR. The other two patches are unrelated improvements. Patches 1-4: Add the 'C' flag feature, a sysctl to optionally enable it, and a selftest. Patch 5: Adjust rp_filter settings in a selftest. Patch 6: Improve rbuf cleanup for MPTCP sockets. ==================== Signed-off-by: -
Paolo Abeni authored
The current cleanup rbuf tries a bit too hard to avoid acquiring the subflow socket lock. We may end-up delaying the needed ack, or skip acking a blocked subflow. Address the above extending the conditions used to trigger the cleanup to reflect more closely what TCP does and invoking tcp_cleanup_rbuf() on all the active subflows. Note that we can't replicate the exact tests implemented in tcp_cleanup_rbuf(), as MPTCP lacks some of the required info - e.g. ping-pong mode. Signed-off-by:
Paolo Abeni <pabeni@redhat.com> Signed-off-by:
Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by:
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Yonglong Li authored
To turn rp_filter off we should: echo 0 > /proc/sys/net/ipv4/conf/default/rp_filter and echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter before NIC created. Co-developed-by:
Yonglong Li <liyonglong@chinatelecom.cn> Signed-off-by:
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Geliang Tang authored
This patch added a new argument '-d' for mptcp_join.sh script, to invoke the testcases for the MP_CAPABLE 'C' flag. Acked-by:
Geliang Tang <geliangtang@gmail.com> Signed-off-by:
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Geliang Tang authored
This patch added a new flag named deny_join_id0 in struct mptcp_options_received. Set it when MP_CAPABLE with the flag MPTCP_CAP_DENYJOIN_ID0 is received. Also add a new flag remote_deny_join_id0 in struct mptcp_pm_data. When the flag deny_join_id0 is set, set this remote_deny_join_id0 flag. In mptcp_pm_create_subflow_or_signal_addr, if the remote_deny_join_id0 flag is set, and the remote address id is zero, stop this connection. Suggested-by:
Florian Westphal <fw@strlen.de> Acked-by:
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Geliang Tang authored
This patch defined a new flag MPTCP_CAP_DENY_JOIN_ID0 for the third bit, labeled "C" of the MP_CAPABLE option. Add a new flag allow_join_id0 in struct mptcp_out_options. If this flag is set, send out the MP_CAPABLE option with the flag MPTCP_CAP_DENY_JOIN_ID0. Acked-by:
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Geliang Tang authored
This patch added a new sysctl, named allow_join_initial_addr_port, to control whether allow peers to send join requests to the IP address and port number used by the initial subflow. Suggested-by:
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David S. Miller authored
Xin Long says: ==================== sctp: implement RFC8899: Packetization Layer Path MTU Discovery for SCTP transport Overview(From RFC8899): In contrast to PMTUD, Packetization Layer Path MTU Discovery (PLPMTUD) [RFC4821] introduces a method that does not rely upon reception and validation of PTB messages. It is therefore more robust than Classical PMTUD. This has become the recommended approach for implementing discovery of the PMTU [BCP145]. It uses a general strategy in which the PL sends probe packets to search for the largest size of unfragmented datagram that can be sent over a network path. Probe packets are sent to explore using a larger packet size. If a probe packet is successfully delivered (as determined by the PL), then the PLPMTU is raised to the size of the successful probe. If a black hole is detected (e.g., where packets of size PLPMTU are consistently not received), the method reduces the PLPMTU. SCTP Probe Packets: As the RFC suggested, the probe packets consist of an SCTP common header followed by a HEARTBEAT chunk and a PAD chunk. The PAD chunk is used to control the length of the probe packet. The HEARTBEAT chunk is used to trigger the sending of a HEARTBEAT ACK chunk to confirm this probe on the HEARTBEAT sender. The HEARTBEAT chunk also carries a Heartbeat Information parameter that includes the probe size to help an implementation associate a HEARTBEAT ACK with the size of probe that was sent. The sender use the nonce and the probe size to verify the information returned. Detailed Implementation on SCTP: +------+ +------->| Base |-----------------+ Connectivity | +------+ | or BASE_PLPMTU | | | confirmation failed | | v | | Connectivity +-------+ | | and BASE_PLPMTU | Error | | | confirmed +-------+ | | | Consistent | v | connectivity Black Hole | +--------+ | and BASE_PLPMTU detected | | Search |<---------------+ confirmed | +--------+ | ^ | | | | | Raise | | Search | timer | | algorithm | expired | | completed | | | | | v | +-----------------+ +---| Search Complete | +-----------------+ When PLPMTUD is enabled, it's in Base state, and starts to probe with BASE_PLPMTU (1200). If this probe succeeds, it goes to Search state; If this probe fails, it goes to Error state under which pl.pmtu goes down to MIN_PLPMTU (512) and keeps probing with BASE_PLPMTU until it succeeds and goes to Search state. During the Search state, the probe size is growing by a Big step (32) every time when the last probe succeeds at the beginning. Once a probe (such as 1420) fails after trying MAX_PROBES (3) times, the probe_size goes back to the last one (1420 - 32 = 1388), meanwhile 'probe_high' is set to 1420 and the growing step becomes a Small one (4). Then the probe is continuing with a Small step grown each round. Until it gets the optimal size (such as 1400) when probe with its next probe size (1404) fails, it sync this size to pathmtu and goes to Complete state. In Complete state, it will only does a probe check for the pathmtu just set, if it fails, which means a Black Hole is detected and it goes back to Base state. If it succeeds, it goes back to Search state again, and probe is continuing with growing a Small step (1400 + 4). If this probe fails, probe_high is set and goes back to 1388 and then Complete state, which is kind of a loop normally. However if the env's pathmtu changes to a big size somehow, this probe will succeed and then probe continues with growing a Big step (1400 + 32) each round until another probe fails. PTB Messages Process: PLPMTUD doesn't rely on these package to find the pmtu, and shouldn't trust it either. When processing them, it only changes the probe_size to PL_PTB_SIZE(info - hlen) if 'pl.pmtu < PL_PTB_SIZE < the current probe_size' druing Search state. As this could help probe_size to get to the optimal size faster, for exmaple: pl.pmtu = 1388, probe_size = 1420, while the env's pathmtu = 1400. When probe_size is 1420, a Toobig packet with 1400 comes back. If probe size changes to use 1400, it will save quite a few rounds to get there. But of course after having this value, PLPMTUD will still verify it on its own before using it. Patches: - Patch 1-6: introduce some new constants/variables from the RFC, systcl and members in transport, APIs for the following patches, chunks and a timer for the probe sending and some codes for the probe receiving. - Patch 7-9: implement the state transition on the tx path, rx path and toobig ICMP packet processing. This is the main algorithm part. - Patch 10: activate this feature - Patch 11-14: improve the process for ICMP packets for SCTP over UDP, so that it can also be covered by this feature. Tests: - do sysctl and setsockopt tests for this feature's enabling and disabling. - get these pr_debug points for this feature by # cat /sys/kernel/debug/dynamic_debug/control | grep PLP and enable them on kernel dynamic debug, then play with the pathmtu and check if the state transition and plpmtu change match the RFC. - do the above tests for SCTP over IPv4/IPv6 and SCTP over UDP. v1->v2: - See Patch 06/14. ==================== Signed-off-by:
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