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* media, bpf: Do not copy more entries than user space requestedSean Young2021-06-241-1/+2
| | | | | | | | | | | | | | | The syscall bpf(BPF_PROG_QUERY, &attr) should use the prog_cnt field to see how many entries user space provided and return ENOSPC if there are more programs than that. Before this patch, this is not checked and ENOSPC is never returned. Note that one lirc device is limited to 64 bpf programs, and user space I'm aware of -- ir-keytable -- always gives enough space for 64 entries already. However, we should not copy program ids than are requested. Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210623213754.632-1-sean@mess.org
* bpf, x86: Remove unused cnt increase from EMIT macroJiri Olsa2021-06-241-32/+12
| | | | | | | | | | | | | Removing unused cnt increase from EMIT macro together with cnt declarations. This was introduced in commit [1] to ensure proper code generation. But that code was removed in commit [2] and this extra code was left in. [1] b52f00e6a715 ("x86: bpf_jit: implement bpf_tail_call() helper") [2] ebf7d1f508a7 ("bpf, x64: rework pro/epilogue and tailcall handling in JIT") Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210623112504.709856-1-jolsa@kernel.org
* docs, af_xdp: Consistent indentation in examplesIlya Maximets2021-06-231-16/+16
| | | | | | | | | | | Examples in this document use all kinds of indentation from 3 to 5 spaces and even mixed with tabs. Making them all even and equal to 4 spaces. Signed-off-by: Ilya Maximets <i.maximets@ovn.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/bpf/20210622185647.3705104-1-i.maximets@ovn.org
* libbpf: Switch to void * casting in netlink helpersKumar Kartikeya Dwivedi2021-06-223-6/+6
| | | | | | | | | | | | | | Netlink helpers I added in 8bbb77b7c7a2 ("libbpf: Add various netlink helpers") used char * casts everywhere, and there were a few more that existed from before. Convert all of them to void * cast, as it is treated equivalently by clang/gcc for the purposes of pointer arithmetic and to follow the convention elsewhere in the kernel/libbpf. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210619041454.417577-2-memxor@gmail.com
* libbpf: Add request buffer type for netlink messagesKumar Kartikeya Dwivedi2021-06-222-82/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Coverity complains about OOB writes to nlmsghdr. There is no OOB as we write to the trailing buffer, but static analyzers and compilers may rightfully be confused as the nlmsghdr pointer has subobject provenance (and hence subobject bounds). Fix this by using an explicit request structure containing the nlmsghdr, struct tcmsg/ifinfomsg, and attribute buffer. Also switch nh_tail (renamed to req_tail) to cast req * to char * so that it can be understood as arithmetic on pointer to the representation array (hence having same bound as request structure), which should further appease analyzers. As a bonus, callers don't have to pass sizeof(req) all the time now, as size is implicitly obtained using the pointer. While at it, also reduce the size of attribute buffer to 128 bytes (132 for ifinfomsg using functions due to the padding). Summary of problem: Even though C standard allows interconvertibility of pointer to first member and pointer to struct, for the purposes of alias analysis it would still consider the first as having pointer value "pointer to T" where T is type of first member hence having subobject bounds, allowing analyzers within reason to complain when object is accessed beyond the size of pointed to object. The only exception to this rule may be when a char * is formed to a member subobject. It is not possible for the compiler to be able to tell the intent of the programmer that it is a pointer to member object or the underlying representation array of the containing object, so such diagnosis is suppressed. Fixes: 715c5ce454a6 ("libbpf: Add low level TC-BPF management API") Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210619041454.417577-1-memxor@gmail.com
* libbpf: Add extra BPF_PROG_TYPE check to bpf_object__probe_loadingJonathan Edwards2021-06-211-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | eBPF has been backported for RHEL 7 w/ kernel 3.10-940+ [0]. However only the following program types are supported [1]: BPF_PROG_TYPE_KPROBE BPF_PROG_TYPE_TRACEPOINT BPF_PROG_TYPE_PERF_EVENT For libbpf this causes an EINVAL return during the bpf_object__probe_loading call which only checks to see if programs of type BPF_PROG_TYPE_SOCKET_FILTER can load. The following will try BPF_PROG_TYPE_TRACEPOINT as a fallback attempt before erroring out. BPF_PROG_TYPE_KPROBE was not a good candidate because on some kernels it requires knowledge of the LINUX_VERSION_CODE. [0] https://www.redhat.com/en/blog/introduction-ebpf-red-hat-enterprise-linux-7 [1] https://access.redhat.com/articles/3550581 Signed-off-by: Jonathan Edwards <jonathan.edwards@165gc.onmicrosoft.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210619151007.GA6963@165gc.onmicrosoft.com
* bpf: Add documentation for libbpf including API autogenGrant Seltzer2021-06-185-18/+103
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is meant to start the initiative to document libbpf. It includes .rst files which are text documentation describing building, API naming convention, as well as an index to generated API documentation. In this approach the generated API documentation is enabled by the kernels existing kernel documentation system which uses sphinx. The resulting docs would then be synced to kernel.org/doc You can test this by running `make htmldocs` and serving the html in Documentation/output. Since libbpf does not yet have comments in kernel doc format, see kernel.org/doc/html/latest/doc-guide/kernel-doc.html for an example so you can test this. The advantage of this approach is to use the existing sphinx infrastructure that the kernel has, and have libbpf docs in the same place as everything else. The current plan is to have the libbpf mirror sync the generated docs and version them based on the libbpf releases which are cut on github. This patch includes the addition of libbpf_api.rst which pulls comment documentation from header files in libbpf under tools/lib/bpf/. The comment docs would be of the standard kernel doc format. Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210618140459.9887-2-grantseltzer@gmail.com
* samples/bpf: Fix the error return code of xdp_redirect's main()Wang Hai2021-06-181-1/+1
| | | | | | | | | | | | Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. If bpf_map_update_elem() failed, main() should return a negative error. Fixes: 832622e6bd18 ("xdp: sample program for new bpf_redirect helper") Signed-off-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210616042534.315097-1-wanghai38@huawei.com
* samples/bpf: Fix Segmentation fault for xdp_redirect commandWang Hai2021-06-181-1/+1
| | | | | | | | | | | | | | | | | | | A Segmentation fault error is caused when the following command is executed. $ sudo ./samples/bpf/xdp_redirect lo Segmentation fault This command is missing a device <IFNAME|IFINDEX> as an argument, resulting in out-of-bounds access from argv. If the number of devices for the xdp_redirect parameter is not 2, we should report an error and exit. Fixes: 24251c264798 ("samples/bpf: add option for native and skb mode for redirect apps") Signed-off-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210616042324.314832-1-wanghai38@huawei.com
* selftests/bpf: Fix ringbuf test fetching map FDAndrii Nakryiko2021-06-181-1/+1
| | | | | | | | | | | | | | Seems like 4d1b62986125 ("selftests/bpf: Convert few tests to light skeleton.") and 704e2beba23c ("selftests/bpf: Test ringbuf mmap read-only and read-write restrictions") were done independently on bpf and bpf-next trees and are in conflict with each other, despite a clean merge. Fix fetching of ringbuf's map_fd to use light skeleton properly. Fixes: 704e2beba23c ("selftests/bpf: Test ringbuf mmap read-only and read-write restrictions") Fixes: 4d1b62986125 ("selftests/bpf: Convert few tests to light skeleton.") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210618002824.2081922-1-andrii@kernel.org
* Merge branch '100GbE' of ↵David S. Miller2021-06-177-26/+18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue Tony Nguyen says: ==================== 100GbE Intel Wired LAN Driver Updates 2021-06-17 This series contains updates to ice driver only. Jake corrects a couple of entries in the PTYPE table to properly reflect the datasheet and removes unneeded NULL checks for some PTP calls. Paul reduces the scope of variables and removes the use of a local variable. Shaokun Zhang removes a duplicate function declaration. Lorenzo Bianconi fixes a compilation warning if PTP_1588_CLOCK is disabled. Colin Ian King changes a for loop to remove an unneeded 'continue'. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * ice: remove redundant continue statement in a for-loopColin Ian King2021-06-171-6/+4
| | | | | | | | | | | | | | | | | | | | The continue statement in the for-loop is redundant. Re-work the hw_lock check to remove it. Addresses-Coverity: ("Continue has no effect") Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * net: ice: ptp: fix compilation warning if PTP_1588_CLOCK is disabledLorenzo Bianconi2021-06-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Fix the following compilation warning if PTP_1588_CLOCK is not enabled drivers/net/ethernet/intel/ice/ice_ptp.h:149:1: error: return type defaults to ‘int’ [-Werror=return-type] ice_ptp_request_ts(struct ice_ptp_tx *tx, struct sk_buff *skb) Fixes: ea9b847cda647 ("ice: enable transmit timestamps for E810 devices") Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * ice: remove unnecessary NULL checks before ptp_read_system_*Jacob Keller2021-06-171-8/+4
| | | | | | | | | | | | | | | | | | | | | | The ptp_read_system_prets and ptp_read_system_postts functions already check for the NULL value of the ptp_system_timestamp structure pointer. There is no need to check this manually in the ice driver code. Remove the checks. Reported-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * ice: Remove the repeated declarationShaokun Zhang2021-06-171-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Function 'ice_is_vsi_valid' is declared twice, remove the repeated declaration. Cc: Jesse Brandeburg <jesse.brandeburg@intel.com> Cc: Tony Nguyen <anthony.l.nguyen@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * ice: remove local variablePaul M Stillwell Jr2021-06-171-2/+1
| | | | | | | | | | | | | | | | | | Remove the local variable since it's only used once. Instead, use it directly. Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com> Tested-by: Tony Brelinski <tonyx.brelinski@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * ice: reduce scope of variablesPaul M Stillwell Jr2021-06-172-6/+6
| | | | | | | | | | | | | | | | | | There are some places where the scope of a variable can be reduced so do that. Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com> Tested-by: Tony Brelinski <tonyx.brelinski@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * ice: mark PTYPE 2 as reservedJacob Keller2021-06-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | The entry for PTYPE 2 in the ice_ptype_lkup table incorrectly states that this is an L2 packet with no payload. According to the datasheet, this PTYPE is actually unused and reserved. Fix the lookup entry to indicate this is an unused entry that is reserved. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Tony Brelinski <tonyx.brelinski@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
| * ice: fix incorrect payload indicator on PTYPEJacob Keller2021-06-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | The entry for PTYPE 90 indicates that the payload is layer 3. This does not match the specification in the datasheet which indicates the packet is a MAC, IPv6, UDP packet, with a payload in layer 4. Fix the lookup table to match the data sheet. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Tony Brelinski <tonyx.brelinski@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
* | Merge branch 'hdlc_ppp-cleanups'David S. Miller2021-06-171-21/+17
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Guangbin Huang says: ==================== net: hdlc_ppp: clean up some code style issues This patchset clean up some code style issues. --- Change Log: V1 -> V2: 1. remove patch "net: hdlc_ppp: fix the comments style issue" and patch "net: hdlc_ppp: remove redundant spaces" from this patchset. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: hdlc_ppp: add required spacePeng Li2021-06-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Add space required after that ','. Signed-off-by: Peng Li <lipeng321@huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: hdlc_ppp: remove unnecessary out of memory messagePeng Li2021-06-171-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes unnecessary out of memory message, to fix the following checkpatch.pl warning: "WARNING: Possible unnecessary 'out of memory' message" Signed-off-by: Peng Li <lipeng321@huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: hdlc_ppp: move out assignment in if conditionPeng Li2021-06-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Should not use assignment in if condition. Signed-off-by: Peng Li <lipeng321@huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: hdlc_ppp: fix the code style issue about "foo* bar"Peng Li2021-06-171-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | Fix the checkpatch error as "foo* bar" or "foo*bar" should be "foo *bar". Signed-off-by: Peng Li <lipeng321@huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: hdlc_ppp: add blank line after declarationsPeng Li2021-06-171-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the checkpatch error about missing a blank line after declarations. Signed-off-by: Peng Li <lipeng321@huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: hdlc_ppp: remove redundant blank linesPeng Li2021-06-171-9/+0
|/ / | | | | | | | | | | | | | | This patch removes some redundant blank lines. Signed-off-by: Peng Li <lipeng321@huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge branch 'mdio-nodes'David S. Miller2021-06-175-8/+14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ioana Ciornei says: ==================== net: mdio: setup both fwnode and of_node The first patch in this series fixes a bug introduced by mistake in the previous ACPI MDIO patch set. The next two patches are adding a new helper which takes a device and a fwnode_handle and populates both the of_node and fwnode so that we make sure that a bug like this does not happen anymore. Also, the new helper is used in the MDIO area. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: mdio: use device_set_node() to setup both fwnode and ofIoana Ciornei2021-06-173-9/+6
| | | | | | | | | | | | | | | | | | | | | | | | Use the newly introduced helper to setup both the of_node and the fwnode for a given device. Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | driver core: add a helper to setup both the of_node and fwnode of a deviceIoana Ciornei2021-06-172-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are many places where both the fwnode_handle and the of_node of a device need to be populated. Add a function which does both so that we have consistency. Suggested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
| * | net: mdio: setup of_node for the MDIO deviceIoana Ciornei2021-06-171-0/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | By mistake, the of_node of the MDIO device was not setup in the patch linked below. As a consequence, any PHY driver that depends on the of_node in its probe callback was not be able to successfully finish its probe on a PHY, thus the Generic PHY driver was used instead. Fix this by actually setting up the of_node. Fixes: bc1bee3b87ee ("net: mdiobus: Introduce fwnode_mdiobus_register_phy()") Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | r8152: store the information of the pipesHayes Wang2021-06-171-5/+13
| | | | | | | | | | | | | | | | | | Store the information of the pipes to avoid calling usb_rcvctrlpipe(), usb_sndctrlpipe(), usb_rcvbulkpipe(), usb_sndbulkpipe(), and usb_rcvintpipe() frequently. Signed-off-by: Hayes Wang <hayeswang@realtek.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller2021-06-17146-1247/+4777
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Daniel Borkmann says: ==================== pull-request: bpf-next 2021-06-17 The following pull-request contains BPF updates for your *net-next* tree. We've added 50 non-merge commits during the last 25 day(s) which contain a total of 148 files changed, 4779 insertions(+), 1248 deletions(-). The main changes are: 1) BPF infrastructure to migrate TCP child sockets from a listener to another in the same reuseport group/map, from Kuniyuki Iwashima. 2) Add a provably sound, faster and more precise algorithm for tnum_mul() as noted in https://arxiv.org/abs/2105.05398, from Harishankar Vishwanathan. 3) Streamline error reporting changes in libbpf as planned out in the 'libbpf: the road to v1.0' effort, from Andrii Nakryiko. 4) Add broadcast support to xdp_redirect_map(), from Hangbin Liu. 5) Extends bpf_map_lookup_and_delete_elem() functionality to 4 more map types, that is, {LRU_,PERCPU_,LRU_PERCPU_,}HASH, from Denis Salopek. 6) Support new LLVM relocations in libbpf to make them more linker friendly, also add a doc to describe the BPF backend relocations, from Yonghong Song. 7) Silence long standing KUBSAN complaints on register-based shifts in interpreter, from Daniel Borkmann and Eric Biggers. 8) Add dummy PT_REGS macros in libbpf to fail BPF program compilation when target arch cannot be determined, from Lorenz Bauer. 9) Extend AF_XDP to support large umems with 1M+ pages, from Magnus Karlsson. 10) Fix two minor libbpf tc BPF API issues, from Kumar Kartikeya Dwivedi. 11) Move libbpf BPF_SEQ_PRINTF/BPF_SNPRINTF macros that can be used by BPF programs to bpf_helpers.h header, from Florent Revest. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * | selftests/bpf: Fix selftests build with old system-wide headersAndrii Nakryiko2021-06-171-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | migrate_reuseport.c selftest relies on having TCP_FASTOPEN_CONNECT defined in system-wide netinet/tcp.h. Selftests can use up-to-date uapi/linux/tcp.h, but that one doesn't have SOL_TCP. So instead of switching everything to uapi header, add #define for TCP_FASTOPEN_CONNECT to fix the build. Fixes: c9d0bdef89a6 ("bpf: Test BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Link: https://lore.kernel.org/bpf/20210617041446.425283-1-andrii@kernel.org
| * | bpf: Fix up register-based shifts in interpreter to silence KUBSANDaniel Borkmann2021-06-171-18/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | syzbot reported a shift-out-of-bounds that KUBSAN observed in the interpreter: [...] UBSAN: shift-out-of-bounds in kernel/bpf/core.c:1420:2 shift exponent 255 is too large for 64-bit type 'long long unsigned int' CPU: 1 PID: 11097 Comm: syz-executor.4 Not tainted 5.12.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327 ___bpf_prog_run.cold+0x19/0x56c kernel/bpf/core.c:1420 __bpf_prog_run32+0x8f/0xd0 kernel/bpf/core.c:1735 bpf_dispatcher_nop_func include/linux/bpf.h:644 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:624 [inline] bpf_prog_run_clear_cb include/linux/filter.h:755 [inline] run_filter+0x1a1/0x470 net/packet/af_packet.c:2031 packet_rcv+0x313/0x13e0 net/packet/af_packet.c:2104 dev_queue_xmit_nit+0x7c2/0xa90 net/core/dev.c:2387 xmit_one net/core/dev.c:3588 [inline] dev_hard_start_xmit+0xad/0x920 net/core/dev.c:3609 __dev_queue_xmit+0x2121/0x2e00 net/core/dev.c:4182 __bpf_tx_skb net/core/filter.c:2116 [inline] __bpf_redirect_no_mac net/core/filter.c:2141 [inline] __bpf_redirect+0x548/0xc80 net/core/filter.c:2164 ____bpf_clone_redirect net/core/filter.c:2448 [inline] bpf_clone_redirect+0x2ae/0x420 net/core/filter.c:2420 ___bpf_prog_run+0x34e1/0x77d0 kernel/bpf/core.c:1523 __bpf_prog_run512+0x99/0xe0 kernel/bpf/core.c:1737 bpf_dispatcher_nop_func include/linux/bpf.h:644 [inline] bpf_test_run+0x3ed/0xc50 net/bpf/test_run.c:50 bpf_prog_test_run_skb+0xabc/0x1c50 net/bpf/test_run.c:582 bpf_prog_test_run kernel/bpf/syscall.c:3127 [inline] __do_sys_bpf+0x1ea9/0x4f00 kernel/bpf/syscall.c:4406 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae [...] Generally speaking, KUBSAN reports from the kernel should be fixed. However, in case of BPF, this particular report caused concerns since the large shift is not wrong from BPF point of view, just undefined. In the verifier, K-based shifts that are >= {64,32} (depending on the bitwidth of the instruction) are already rejected. The register-based cases were not given their content might not be known at verification time. Ideas such as verifier instruction rewrite with an additional AND instruction for the source register were brought up, but regularly rejected due to the additional runtime overhead they incur. As Edward Cree rightly put it: Shifts by more than insn bitness are legal in the BPF ISA; they are implementation-defined behaviour [of the underlying architecture], rather than UB, and have been made legal for performance reasons. Each of the JIT backends compiles the BPF shift operations to machine instructions which produce implementation-defined results in such a case; the resulting contents of the register may be arbitrary but program behaviour as a whole remains defined. Guard checks in the fast path (i.e. affecting JITted code) will thus not be accepted. The case of division by zero is not truly analogous here, as division instructions on many of the JIT-targeted architectures will raise a machine exception / fault on division by zero, whereas (to the best of my knowledge) none will do so on an out-of-bounds shift. Given the KUBSAN report only affects the BPF interpreter, but not JITs, one solution is to add the ANDs with 63 or 31 into ___bpf_prog_run(). That would make the shifts defined, and thus shuts up KUBSAN, and the compiler would optimize out the AND on any CPU that interprets the shift amounts modulo the width anyway (e.g., confirmed from disassembly that on x86-64 and arm64 the generated interpreter code is the same before and after this fix). The BPF interpreter is slow path, and most likely compiled out anyway as distros select BPF_JIT_ALWAYS_ON to avoid speculative execution of BPF instructions by the interpreter. Given the main argument was to avoid sacrificing performance, the fact that the AND is optimized away from compiler for mainstream archs helps as well as a solution moving forward. Also add a comment on LSH/RSH/ARSH translation for JIT authors to provide guidance when they see the ___bpf_prog_run() interpreter code and use it as a model for a new JIT backend. Reported-by: syzbot+bed360704c521841c85d@syzkaller.appspotmail.com Reported-by: Kurt Manucredo <fuzzybritches0@gmail.com> Signed-off-by: Eric Biggers <ebiggers@kernel.org> Co-developed-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: syzbot+bed360704c521841c85d@syzkaller.appspotmail.com Cc: Edward Cree <ecree.xilinx@gmail.com> Link: https://lore.kernel.org/bpf/0000000000008f912605bd30d5d7@google.com Link: https://lore.kernel.org/bpf/bac16d8d-c174-bdc4-91bd-bfa62b410190@gmail.com
| * | libbpf: Fail compilation if target arch is missingLorenz Bauer2021-06-171-4/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bpf2go is the Go equivalent of libbpf skeleton. The convention is that the compiled BPF is checked into the repository to facilitate distributing BPF as part of Go packages. To make this portable, bpf2go by default generates both bpfel and bpfeb variants of the C. Using bpf_tracing.h is inherently non-portable since the fields of struct pt_regs differ between platforms, so CO-RE can't help us here. The only way of working around this is to compile for each target platform independently. bpf2go can't do this by default since there are too many platforms. Define the various PT_... macros when no target can be determined and turn them into compilation failures. This works because bpf2go always compiles for bpf targets, so the compiler fallback doesn't kick in. Conditionally define __BPF_MISSING_TARGET so that we can inject a more appropriate error message at build time. The user can then choose which platform to target explicitly. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210616083635.11434-1-lmb@cloudflare.com
| * | samples/bpf: Add missing option to xdp_sample_pkts usageWang Hai2021-06-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | xdp_sample_pkts usage() is missing the introduction of the "-S" option, this patch adds it. Fixes: d50ecc46d18f ("samples/bpf: Attach XDP programs in driver mode by default") Signed-off-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/20210615135724.29528-1-wanghai38@huawei.com
| * | samples/bpf: Add missing option to xdp_fwd usageWang Hai2021-06-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | xdp_fwd usage() is missing the introduction of the "-S" and "-F" options, this patch adds it. Fixes: d50ecc46d18f ("samples/bpf: Attach XDP programs in driver mode by default") Signed-off-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/20210615135554.29158-1-wanghai38@huawei.com
| * | bpf: Fix typo in kernel/bpf/bpf_lsm.cShuyi Cheng2021-06-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Fix s/sleeable/sleepable/ typo in a comment. Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1623809076-97907-1-git-send-email-chengshuyi@linux.alibaba.com
| * | selftests/bpf: Whitelist test_progs.h from .gitignoreDaniel Xu2021-06-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Somehow test_progs.h was being included by the existing rule: /test_progs* This is bad because: 1) test_progs.h is a checked in file 2) grep-like tools like ripgrep[0] respect gitignore and test_progs.h was being hidden from searches [0]: https://github.com/BurntSushi/ripgrep Fixes: 74b5a5968fe8 ("selftests/bpf: Replace test_progs and test_maps w/ general rule") Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/a46f64944bf678bc652410ca6028d3450f4f7f4b.1623880296.git.dxu@dxuuu.xyz
| * | Merge branch 'bpf-sock-migration'Daniel Borkmann2021-06-1521-68/+1335
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kuniyuki Iwashima says: ==================== The SO_REUSEPORT option allows sockets to listen on the same port and to accept connections evenly. However, there is a defect in the current implementation [1]. When a SYN packet is received, the connection is tied to a listening socket. Accordingly, when the listener is closed, in-flight requests during the three-way handshake and child sockets in the accept queue are dropped even if other listeners on the same port could accept such connections. This situation can happen when various server management tools restart server (such as nginx) processes. For instance, when we change nginx configurations and restart it, it spins up new workers that respect the new configuration and closes all listeners on the old workers, resulting in the in-flight ACK of 3WHS is responded by RST. To avoid such a situation, users have to know deeply how the kernel handles SYN packets and implement connection draining by eBPF [2]: 1. Stop routing SYN packets to the listener by eBPF. 2. Wait for all timers to expire to complete requests 3. Accept connections until EAGAIN, then close the listener. or 1. Start counting SYN packets and accept syscalls using the eBPF map. 2. Stop routing SYN packets. 3. Accept connections up to the count, then close the listener. In either way, we cannot close a listener immediately. However, ideally, the application need not drain the not yet accepted sockets because 3WHS and tying a connection to a listener are just the kernel behaviour. The root cause is within the kernel, so the issue should be addressed in kernel space and should not be visible to user space. This patchset fixes it so that users need not take care of kernel implementation and connection draining. With this patchset, the kernel redistributes requests and connections from a listener to the others in the same reuseport group at/after close or shutdown syscalls. Although some software does connection draining, there are still merits in migration. For some security reasons, such as replacing TLS certificates, we may want to apply new settings as soon as possible and/or we may not be able to wait for connection draining. The sockets in the accept queue have not started application sessions yet. So, if we do not drain such sockets, they can be handled by the newer listeners and could have a longer lifetime. It is difficult to drain all connections in every case, but we can decrease such aborted connections by migration. In that sense, migration is always better than draining. Moreover, auto-migration simplifies user space logic and also works well in a case where we cannot modify and build a server program to implement the workaround. Note that the source and destination listeners MUST have the same settings at the socket API level; otherwise, applications may face inconsistency and cause errors. In such a case, we have to use the eBPF program to select a specific listener or to cancel migration. Special thanks to Martin KaFai Lau for bouncing ideas and exchanging code snippets along the way. Link: [1] The SO_REUSEPORT socket option https://lwn.net/Articles/542629/ [2] Re: [PATCH 1/1] net: Add SO_REUSEPORT_LISTEN_OFF socket option as drain mode https://lore.kernel.org/netdev/1458828813.10868.65.camel@edumazet-glaptop3.roam.corp.google.com/ Changelog: v8: * Make reuse const in reuseport_sock_index() * Don't use __reuseport_add_sock() in reuseport_alloc() * Change the arg of the second memcpy() in reuseport_grow() * Fix coding style to use goto in reuseport_alloc() * Keep sk_refcnt uninitialized in inet_reqsk_clone() * Initialize ireq_opt and ipv6_opt separately in reqsk_migrate_reset() [ This series does not include a stats patch suggested by Yuchung Cheng not to drop Acked-by/Reviewed-by tags and save reviewer's time. I will post the patch as a follow up after this series is merged. ] v7: https://lore.kernel.org/bpf/20210521182104.18273-1-kuniyu@amazon.co.jp/ * Prevent attaching/detaching a bpf prog via shutdowned socket * Fix typo in commit messages * Split selftest into subtests v6: https://lore.kernel.org/bpf/20210517002258.75019-1-kuniyu@amazon.co.jp/ * Change description in ip-sysctl.rst * Test IPPROTO_TCP before reading tfo_listener * Move reqsk_clone() to inet_connection_sock.c and rename to inet_reqsk_clone() * Pass req->rsk_listener to inet_csk_reqsk_queue_drop() and reqsk_queue_removed() in the migration path of receiving ACK * s/ARG_PTR_TO_SOCKET/PTR_TO_SOCKET/ in sk_reuseport_is_valid_access() * In selftest, use atomic ops to increment global vars, drop ACK by XDP, enable force fastopen, use "skel->bss" instead of "skel->data" v5: https://lore.kernel.org/bpf/20210510034433.52818-1-kuniyu@amazon.co.jp/ * Move initializtion of sk_node from 6th to 5th patch * Initialize sk_refcnt in reqsk_clone() * Modify some definitions in reqsk_timer_handler() * Validate in which path/state migration happens in selftest v4: https://lore.kernel.org/bpf/20210427034623.46528-1-kuniyu@amazon.co.jp/ * Make some functions and variables 'static' in selftest * Remove 'scalability' from the cover letter v3: https://lore.kernel.org/bpf/20210420154140.80034-1-kuniyu@amazon.co.jp/ * Add sysctl back for reuseport_grow() * Add helper functions to manage socks[] * Separate migration related logic into functions: reuseport_resurrect(), reuseport_stop_listen_sock(), reuseport_migrate_sock() * Clone request_sock to be migrated * Migrate request one by one * Pass child socket to eBPF prog v2: https://lore.kernel.org/netdev/20201207132456.65472-1-kuniyu@amazon.co.jp/ * Do not save closed sockets in socks[] * Revert 607904c357c61adf20b8fd18af765e501d61a385 * Extract inet_csk_reqsk_queue_migrate() into a single patch * Change the spin_lock order to avoid lockdep warning * Add static to __reuseport_select_sock * Use refcount_inc_not_zero() in reuseport_select_migrated_sock() * Set the default attach type in bpf_prog_load_check_attach() * Define new proto of BPF_FUNC_get_socket_cookie * Fix test to be compiled successfully * Update commit messages v1: https://lore.kernel.org/netdev/20201201144418.35045-1-kuniyu@amazon.co.jp/ * Remove the sysctl option * Enable migration if eBPF progam is not attached * Add expected_attach_type to check if eBPF program can migrate sockets * Add a field to tell migration type to eBPF program * Support BPF_FUNC_get_socket_cookie to get the cookie of sk * Allocate an empty skb if skb is NULL * Pass req_to_sk(req)->sk_hash because listener's hash is zero * Update commit messages and coverletter RFC: https://lore.kernel.org/netdev/20201117094023.3685-1-kuniyu@amazon.co.jp/ ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| | * | bpf: Test BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.Kuniyuki Iwashima2021-06-154-1/+692
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a test for BPF_SK_REUSEPORT_SELECT_OR_MIGRATE and removes 'static' from settimeo() in network_helpers.c. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-12-kuniyu@amazon.co.jp
| | * | libbpf: Set expected_attach_type for BPF_PROG_TYPE_SK_REUSEPORT.Kuniyuki Iwashima2021-06-151-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit introduces a new section (sk_reuseport/migrate) and sets expected_attach_type to two each section in BPF_PROG_TYPE_SK_REUSEPORT program. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-11-kuniyu@amazon.co.jp
| | * | bpf: Support socket migration by eBPF.Kuniyuki Iwashima2021-06-157-5/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces a new bpf_attach_type for BPF_PROG_TYPE_SK_REUSEPORT to check if the attached eBPF program is capable of migrating sockets. When the eBPF program is attached, we run it for socket migration if the expected_attach_type is BPF_SK_REUSEPORT_SELECT_OR_MIGRATE or net.ipv4.tcp_migrate_req is enabled. Currently, the expected_attach_type is not enforced for the BPF_PROG_TYPE_SK_REUSEPORT type of program. Thus, this commit follows the earlier idea in the commit aac3fc320d94 ("bpf: Post-hooks for sys_bind") to fix up the zero expected_attach_type in bpf_prog_load_fixup_attach_type(). Moreover, this patch adds a new field (migrating_sk) to sk_reuseport_md to select a new listener based on the child socket. migrating_sk varies depending on if it is migrating a request in the accept queue or during 3WHS. - accept_queue : sock (ESTABLISHED/SYN_RECV) - 3WHS : request_sock (NEW_SYN_RECV) In the eBPF program, we can select a new listener by BPF_FUNC_sk_select_reuseport(). Also, we can cancel migration by returning SK_DROP. This feature is useful when listeners have different settings at the socket API level or when we want to free resources as soon as possible. - SK_PASS with selected_sk, select it as a new listener - SK_PASS with selected_sk NULL, fallbacks to the random selection - SK_DROP, cancel the migration. There is a noteworthy point. We select a listening socket in three places, but we do not have struct skb at closing a listener or retransmitting a SYN+ACK. On the other hand, some helper functions do not expect skb is NULL (e.g. skb_header_pointer() in BPF_FUNC_skb_load_bytes(), skb_tail_pointer() in BPF_FUNC_skb_load_bytes_relative()). So we allocate an empty skb temporarily before running the eBPF program. Suggested-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/netdev/20201123003828.xjpjdtk4ygl6tg6h@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/netdev/20201203042402.6cskdlit5f3mw4ru@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/netdev/20201209030903.hhow5r53l6fmozjn@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/bpf/20210612123224.12525-10-kuniyu@amazon.co.jp
| | * | bpf: Support BPF_FUNC_get_socket_cookie() for BPF_PROG_TYPE_SK_REUSEPORT.Kuniyuki Iwashima2021-06-153-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We will call sock_reuseport.prog for socket migration in the next commit, so the eBPF program has to know which listener is closing to select a new listener. We can currently get a unique ID of each listener in the userspace by calling bpf_map_lookup_elem() for BPF_MAP_TYPE_REUSEPORT_SOCKARRAY map. This patch makes the pointer of sk available in sk_reuseport_md so that we can get the ID by BPF_FUNC_get_socket_cookie() in the eBPF program. Suggested-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/netdev/20201119001154.kapwihc2plp4f7zc@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/bpf/20210612123224.12525-9-kuniyu@amazon.co.jp
| | * | tcp: Migrate TCP_NEW_SYN_RECV requests at receiving the final ACK.Kuniyuki Iwashima2021-06-154-14/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch also changes the code to call reuseport_migrate_sock() and inet_reqsk_clone(), but unlike the other cases, we do not call inet_reqsk_clone() right after reuseport_migrate_sock(). Currently, in the receive path for TCP_NEW_SYN_RECV sockets, its listener has three kinds of refcnt: (A) for listener itself (B) carried by reuqest_sock (C) sock_hold() in tcp_v[46]_rcv() While processing the req, (A) may disappear by close(listener). Also, (B) can disappear by accept(listener) once we put the req into the accept queue. So, we have to hold another refcnt (C) for the listener to prevent use-after-free. For socket migration, we call reuseport_migrate_sock() to select a listener with (A) and to increment the new listener's refcnt in tcp_v[46]_rcv(). This refcnt corresponds to (C) and is cleaned up later in tcp_v[46]_rcv(). Thus we have to take another refcnt (B) for the newly cloned request_sock. In inet_csk_complete_hashdance(), we hold the count (B), clone the req, and try to put the new req into the accept queue. By migrating req after winning the "own_req" race, we can avoid such a worst situation: CPU 1 looks up req1 CPU 2 looks up req1, unhashes it, then CPU 1 loses the race CPU 3 looks up req2, unhashes it, then CPU 2 loses the race ... Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-8-kuniyu@amazon.co.jp
| | * | tcp: Migrate TCP_NEW_SYN_RECV requests at retransmitting SYN+ACKs.Kuniyuki Iwashima2021-06-151-6/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As with the preceding patch, this patch changes reqsk_timer_handler() to call reuseport_migrate_sock() and inet_reqsk_clone() to migrate in-flight requests at retransmitting SYN+ACKs. If we can select a new listener and clone the request, we resume setting the SYN+ACK timer for the new req. If we can set the timer, we call inet_ehash_insert() to unhash the old req and put the new req into ehash. The noteworthy point here is that by unhashing the old req, another CPU processing it may lose the "own_req" race in tcp_v[46]_syn_recv_sock() and drop the final ACK packet. However, the new timer will recover this situation. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-7-kuniyu@amazon.co.jp
| | * | tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues.Kuniyuki Iwashima2021-06-151-1/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we call close() or shutdown() for listening sockets, each child socket in the accept queue are freed at inet_csk_listen_stop(). If we can get a new listener by reuseport_migrate_sock() and clone the request by inet_reqsk_clone(), we try to add it into the new listener's accept queue by inet_csk_reqsk_queue_add(). If it fails, we have to call __reqsk_free() to call sock_put() for its listener and free the cloned request. After putting the full socket into ehash, tcp_v[46]_syn_recv_sock() sets NULL to ireq_opt/pktopts in struct inet_request_sock, but ipv6_opt can be non-NULL. So, we have to set NULL to ipv6_opt of the old request to avoid double free. Note that we do not update req->rsk_listener and instead clone the req to migrate because another path may reference the original request. If we protected it by RCU, we would need to add rcu_read_lock() in many places. Suggested-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/netdev/20201209030903.hhow5r53l6fmozjn@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/bpf/20210612123224.12525-6-kuniyu@amazon.co.jp
| | * | tcp: Add reuseport_migrate_sock() to select a new listener.Kuniyuki Iwashima2021-06-152-14/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | reuseport_migrate_sock() does the same check done in reuseport_listen_stop_sock(). If the reuseport group is capable of migration, reuseport_migrate_sock() selects a new listener by the child socket hash and increments the listener's sk_refcnt beforehand. Thus, if we fail in the migration, we have to decrement it later. We will support migration by eBPF in the later commits. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-5-kuniyu@amazon.co.jp
| | * | tcp: Keep TCP_CLOSE sockets in the reuseport group.Kuniyuki Iwashima2021-06-154-11/+186
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we close a listening socket, to migrate its connections to another listener in the same reuseport group, we have to handle two kinds of child sockets. One is that a listening socket has a reference to, and the other is not. The former is the TCP_ESTABLISHED/TCP_SYN_RECV sockets, and they are in the accept queue of their listening socket. So we can pop them out and push them into another listener's queue at close() or shutdown() syscalls. On the other hand, the latter, the TCP_NEW_SYN_RECV socket is during the three-way handshake and not in the accept queue. Thus, we cannot access such sockets at close() or shutdown() syscalls. Accordingly, we have to migrate immature sockets after their listening socket has been closed. Currently, if their listening socket has been closed, TCP_NEW_SYN_RECV sockets are freed at receiving the final ACK or retransmitting SYN+ACKs. At that time, if we could select a new listener from the same reuseport group, no connection would be aborted. However, we cannot do that because reuseport_detach_sock() sets NULL to sk_reuseport_cb and forbids access to the reuseport group from closed sockets. This patch allows TCP_CLOSE sockets to remain in the reuseport group and access it while any child socket references them. The point is that reuseport_detach_sock() was called twice from inet_unhash() and sk_destruct(). This patch replaces the first reuseport_detach_sock() with reuseport_stop_listen_sock(), which checks if the reuseport group is capable of migration. If capable, it decrements num_socks, moves the socket backwards in socks[] and increments num_closed_socks. When all connections are migrated, sk_destruct() calls reuseport_detach_sock() to remove the socket from socks[], decrement num_closed_socks, and set NULL to sk_reuseport_cb. By this change, closed or shutdowned sockets can keep sk_reuseport_cb. Consequently, calling listen() after shutdown() can cause EADDRINUSE or EBUSY in inet_csk_bind_conflict() or reuseport_add_sock() which expects such sockets not to have the reuseport group. Therefore, this patch also loosens such validation rules so that a socket can listen again if it has a reuseport group with num_closed_socks more than 0. When such sockets listen again, we handle them in reuseport_resurrect(). If there is an existing reuseport group (reuseport_add_sock() path), we move the socket from the old group to the new one and free the old one if necessary. If there is no existing group (reuseport_alloc() path), we allocate a new reuseport group, detach sk from the old one, and free it if necessary, not to break the current shutdown behaviour: - we cannot carry over the eBPF prog of shutdowned sockets - we cannot attach/detach an eBPF prog to/from listening sockets via shutdowned sockets Note that when the number of sockets gets over U16_MAX, we try to detach a closed socket randomly to make room for the new listening socket in reuseport_grow(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-4-kuniyu@amazon.co.jp
| | * | tcp: Add num_closed_socks to struct sock_reuseport.Kuniyuki Iwashima2021-06-152-20/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As noted in the following commit, a closed listener has to hold the reference to the reuseport group for socket migration. This patch adds a field (num_closed_socks) to struct sock_reuseport to manage closed sockets within the same reuseport group. Moreover, this and the following commits introduce some helper functions to split socks[] into two sections and keep TCP_LISTEN and TCP_CLOSE sockets in each section. Like a double-ended queue, we will place TCP_LISTEN sockets from the front and TCP_CLOSE sockets from the end. TCP_LISTEN----------> <-------TCP_CLOSE +---+---+ --- +---+ --- +---+ --- +---+ | 0 | 1 | ... | i | ... | j | ... | k | +---+---+ --- +---+ --- +---+ --- +---+ i = num_socks - 1 j = max_socks - num_closed_socks k = max_socks - 1 This patch also extends reuseport_add_sock() and reuseport_grow() to support num_closed_socks. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210612123224.12525-3-kuniyu@amazon.co.jp