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* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2019-06-221-4/+1
|\ | | | | | | | | | | Minor SPDX change conflict. Signed-off-by: David S. Miller <davem@davemloft.net>
| * treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner2019-06-191-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | net/tls: fully initialize the msg wrapper skbJakub Kicinski2019-06-041-6/+2
|/ | | | | | | | | | | | | | | | | | | If strparser gets cornered into starting a new message from an sk_buff which already has frags, it will allocate a new skb to become the "wrapper" around the fragments of the message. This new skb does not inherit any metadata fields. In case of TLS offload this may lead to unnecessarily re-encrypting the message, as skb->decrypted is not set for the wrapper skb. Try to be conservative and copy all fields of old skb strparser's user may reasonably need. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-212-0/+2
| | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* net: strparser: make it explicitly non-modularPaul Gortmaker2019-04-221-10/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The Kconfig currently controlling compilation of this code is: net/strparser/Kconfig:config STREAM_PARSER net/strparser/Kconfig: def_bool n ...meaning that it currently is not being built as a module by anyone. Lets remove the modular code that is essentially orphaned, so that when reading the driver there is no doubt it is builtin-only. Since module_init translates to device_initcall in the non-modular case, the init ordering remains unchanged with this commit. For clarity, we change the fcn name mod_init to dev_init at the same time. We replace module.h with init.h and export.h ; the latter since this file exports some syms. Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Song Liu <songliubraving@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2019-04-171-7/+5
|\ | | | | | | | | | | Conflict resolution of af_smc.c from Stephen Rothwell. Signed-off-by: David S. Miller <davem@davemloft.net>
| * net: strparser: partially revert "strparser: Call skb_unclone conditionally"Jakub Kicinski2019-04-101-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts the first part of commit 4e485d06bb8c ("strparser: Call skb_unclone conditionally"). To build a message with multiple fragments we need our own root of frag_list. We can't simply use the frag_list of orig_skb, because it will lead to linking all orig_skbs together creating very long frag chains, and causing stack overflow on kfree_skb() (which is called recursively on the frag_lists). BUG: stack guard page was hit at 00000000d40fad41 (stack is 0000000029dde9f4..000000008cce03d5) kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP RIP: 0010:free_one_page+0x2b/0x490 Call Trace: __free_pages_ok+0x143/0x2c0 skb_release_data+0x8e/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 [...] skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 __kfree_skb+0xe/0x20 tcp_disconnect+0xd6/0x4d0 tcp_close+0xf4/0x430 ? tcp_check_oom+0xf0/0xf0 tls_sk_proto_close+0xe4/0x1e0 [tls] inet_release+0x36/0x60 __sock_release+0x37/0xa0 sock_close+0x11/0x20 __fput+0xa2/0x1d0 task_work_run+0x89/0xb0 exit_to_usermode_loop+0x9a/0xa0 do_syscall_64+0xc0/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Let's leave the second unclone conditional, as I'm not entirely sure what is its purpose :) Fixes: 4e485d06bb8c ("strparser: Call skb_unclone conditionally") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net: strparser: fix commentJakub Kicinski2019-04-101-1/+1
|/ | | | | | | Fix comment. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: strparser: fix a missing check for create_singlethread_workqueueKangjie Lu2019-03-151-0/+2
| | | | | | | | In case create_singlethread_workqueue fails, the check returns an error to callers to avoid potential NULL pointer dereferences. Signed-off-by: Kangjie Lu <kjlu@umn.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf, sockmap: convert to generic sk_msg interfaceDaniel Borkmann2018-10-151-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a generic sk_msg layer, and convert current sockmap and later kTLS over to make use of it. While sk_buff handles network packet representation from netdevice up to socket, sk_msg handles data representation from application to socket layer. This means that sk_msg framework spans across ULP users in the kernel, and enables features such as introspection or filtering of data with the help of BPF programs that operate on this data structure. Latter becomes in particular useful for kTLS where data encryption is deferred into the kernel, and as such enabling the kernel to perform L7 introspection and policy based on BPF for TLS connections where the record is being encrypted after BPF has run and came to a verdict. In order to get there, first step is to transform open coding of scatter-gather list handling into a common core framework that subsystems can use. The code itself has been split and refactored into three bigger pieces: i) the generic sk_msg API which deals with managing the scatter gather ring, providing helpers for walking and mangling, transferring application data from user space into it, and preparing it for BPF pre/post-processing, ii) the plain sock map itself where sockets can be attached to or detached from; these bits are independent of i) which can now be used also without sock map, and iii) the integration with plain TCP as one protocol to be used for processing L7 application data (later this could e.g. also be extended to other protocols like UDP). The semantics are the same with the old sock map code and therefore no change of user facing behavior or APIs. While pursuing this work it also helped finding a number of bugs in the old sockmap code that we've fixed already in earlier commits. The test_sockmap kselftest suite passes through fine as well. Joint work with John. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* strparser: remove redundant variable 'rd_desc'YueHaibing2018-08-011-4/+0
| | | | | | | | | | | Variable 'rd_desc' is being assigned but never used, so can be removed. fix this clang warning: net/strparser/strparser.c:411:20: warning: variable ‘rd_desc’ set but not used [-Wunused-but-set-variable] Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/netDavid S. Miller2018-07-031-16/+1
|\ | | | | | | | | | | | | | | | | | | Simple overlapping changes in stmmac driver. Adjust skb_gro_flush_final_remcsum function signature to make GRO list changes in net-next, as per Stephen Rothwell's example merge resolution. Signed-off-by: David S. Miller <davem@davemloft.net>
| * strparser: Remove early eaten to fix full tcp receive buffer stallDoron Roberts-Kedes2018-06-281-16/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On receving an incomplete message, the existing code stores the remaining length of the cloned skb in the early_eaten field instead of incrementing the value returned by __strp_recv. This defers invocation of sock_rfree for the current skb until the next invocation of __strp_recv, which returns early_eaten if early_eaten is non-zero. This behavior causes a stall when the current message occupies the very tail end of a massive skb, and strp_peek/need_bytes indicates that the remainder of the current message has yet to arrive on the socket. The TCP receive buffer is totally full, causing the TCP window to go to zero, so the remainder of the message will never arrive. Incrementing the value returned by __strp_recv by the amount otherwise stored in early_eaten prevents stalls of this nature. Signed-off-by: Doron Roberts-Kedes <doronrk@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | strparser: Call skb_unclone conditionallyVakul Garg2018-06-301-11/+15
|/ | | | | | | | | | Calling skb_unclone() is expensive as it triggers a memcpy operation. Instead of calling skb_unclone() unconditionally, call it only when skb has a shared frag_list. This improves tls rx throughout significantly. Signed-off-by: Vakul Garg <vakul.garg@nxp.com> Suggested-by: Boris Pismenny <borisp@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Don't schedule in workqueue in paused stateVakul Garg2018-06-211-4/+1
| | | | | | | | | | | | In function strp_data_ready(), it is useless to call queue_work if the state of strparser is already paused. The state checking should be done before calling queue_work. The change reduces the context switches and improves the ktls-rx throughput by approx 20% (measured on cortex-a53 based platform). Signed-off-by: Vakul Garg <vakul.garg@nxp.com> Acked-by: Dave Watson <davejwatson@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Add __strp_unpause and use it in ktls.Doron Roberts-Kedes2018-06-061-0/+13
| | | | | | | | | | | | | | | | | strp_unpause queues strp_work in order to parse any messages that arrived while the strparser was paused. However, the process invoking strp_unpause could eagerly parse a buffered message itself if it held the sock lock. __strp_unpause is an alternative to strp_pause that avoids the scheduling overhead that results when a receiving thread unpauses the strparser and waits for the next message to be delivered by the workqueue thread. This patch more than doubled the IOPS achieved in a benchmark of NBD traffic encrypted using ktls. Signed-off-by: Doron Roberts-Kedes <doronrk@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Do not call mod_delayed_work with a timeout of LONG_MAXDoron Roberts-Kedes2018-04-221-1/+1
| | | | | | | | | | | | | | | | | | struct sock's sk_rcvtimeo is initialized to LONG_MAX/MAX_SCHEDULE_TIMEOUT in sock_init_data. Calling mod_delayed_work with a timeout of LONG_MAX causes spurious execution of the work function. timer->expires is set equal to jiffies + LONG_MAX. When timer_base->clk falls behind the current value of jiffies, the delta between timer_base->clk and jiffies + LONG_MAX causes the expiration to be in the past. Returning early from strp_start_timer if timeo == LONG_MAX solves this problem. Found while testing net/tls_sw recv path. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: Doron Roberts-Kedes <doronrk@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Fix incorrect strp->need_bytes value.Doron Roberts-Kedes2018-04-121-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | strp_data_ready resets strp->need_bytes to 0 if strp_peek_len indicates that the remainder of the message has been received. However, do_strp_work does not reset strp->need_bytes to 0. If do_strp_work completes a partial message, the value of strp->need_bytes will continue to reflect the needed bytes of the previous message, causing future invocations of strp_data_ready to return early if strp->need_bytes is less than strp_peek_len. Resetting strp->need_bytes to 0 in __strp_recv on handing a full message to the upper layer solves this problem. __strp_recv also calculates strp->need_bytes using stm->accum_len before stm->accum_len has been incremented by cand_len. This can cause strp->need_bytes to be equal to the full length of the message instead of the full length minus the accumulated length. This, in turn, causes strp_data_ready to return early, even when there is sufficient data to complete the partial message. Incrementing stm->accum_len before using it to calculate strp->need_bytes solves this problem. Found while testing net/tls_sw recv path. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Signed-off-by: Doron Roberts-Kedes <doronrk@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Fix sign of err codesDave Watson2018-03-271-2/+2
| | | | | | | | | | | | | | | | | | | strp_parser_err is called with a negative code everywhere, which then calls abort_parser with a negative code. strp_msg_timeout calls abort_parser directly with a positive code. Negate ETIMEDOUT to match signed-ness of other calls. The default abort_parser callback, strp_abort_strp, sets sk->sk_err to err. Also negate the error here so sk_err always holds a positive value, as the rest of the net code expects. Currently a negative sk_err can result in endless loops, or user code that thinks it actually sent/received err bytes. Found while testing net/tls_sw recv path. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Signed-off-by: Dave Watson <davejwatson@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Call sock_owned_by_user_nocheckTom Herbert2017-12-281-1/+1
| | | | | | | | | | | | strparser wants to check socket ownership without producing any warnings. As indicated by the comment in the code, it is permissible for owned_by_user to return true. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Reported-by: syzbot <syzkaller@googlegroups.com> Reported-and-tested-by: <syzbot+c91c53af67f9ebe599a337d2e70950366153b295@syzkaller.appspotmail.com> Signed-off-by: Tom Herbert <tom@quantonium.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Use delayed work instead of timer for msg timeoutTom Herbert2017-10-251-9/+8
| | | | | | | | | | Sock lock may be taken in the message timer function which is a problem since timers run in BH. Instead of timers use delayed_work. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Fixes: bbb03029a899 ("strparser: Generalize strparser") Signed-off-by: Tom Herbert <tom@quantonium.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: initialize all callbacksEric Biggers2017-08-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit bbb03029a899 ("strparser: Generalize strparser") added more function pointers to 'struct strp_callbacks'; however, kcm_attach() was not updated to initialize them. This could cause the ->lock() and/or ->unlock() function pointers to be set to garbage values, causing a crash in strp_work(). Fix the bug by moving the callback structs into static memory, so unspecified members are zeroed. Also constify them while we're at it. This bug was found by syzkaller, which encountered the following splat: IP: 0x55 PGD 3b1ca067 P4D 3b1ca067 PUD 3b12f067 PMD 0 Oops: 0010 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 2 PID: 1194 Comm: kworker/u8:1 Not tainted 4.13.0-rc4-next-20170811 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: kstrp strp_work task: ffff88006bb0e480 task.stack: ffff88006bb10000 RIP: 0010:0x55 RSP: 0018:ffff88006bb17540 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88006ce4bd60 RCX: 0000000000000000 RDX: 1ffff1000d9c97bd RSI: 0000000000000000 RDI: ffff88006ce4bc48 RBP: ffff88006bb17558 R08: ffffffff81467ab2 R09: 0000000000000000 R10: ffff88006bb17438 R11: ffff88006bb17940 R12: ffff88006ce4bc48 R13: ffff88003c683018 R14: ffff88006bb17980 R15: ffff88003c683000 FS: 0000000000000000(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000055 CR3: 000000003c145000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2098 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Code: Bad RIP value. RIP: 0x55 RSP: ffff88006bb17540 CR2: 0000000000000055 ---[ end trace f0e4920047069cee ]--- Here is a C reproducer (requires CONFIG_BPF_SYSCALL=y and CONFIG_AF_KCM=y): #include <linux/bpf.h> #include <linux/kcm.h> #include <linux/types.h> #include <stdint.h> #include <sys/ioctl.h> #include <sys/socket.h> #include <sys/syscall.h> #include <unistd.h> static const struct bpf_insn bpf_insns[3] = { { .code = 0xb7 }, /* BPF_MOV64_IMM(0, 0) */ { .code = 0x95 }, /* BPF_EXIT_INSN() */ }; static const union bpf_attr bpf_attr = { .prog_type = 1, .insn_cnt = 2, .insns = (uintptr_t)&bpf_insns, .license = (uintptr_t)"", }; int main(void) { int bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &bpf_attr, sizeof(bpf_attr)); int inet_fd = socket(AF_INET, SOCK_STREAM, 0); int kcm_fd = socket(AF_KCM, SOCK_DGRAM, 0); ioctl(kcm_fd, SIOCKCMATTACH, &(struct kcm_attach) { .fd = inet_fd, .bpf_fd = bpf_fd }); } Fixes: bbb03029a899 ("strparser: Generalize strparser") Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Tom Herbert <tom@quantonium.net> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: early init support for strparserJohn Fastabend2017-08-161-6/+4
| | | | | | | | It is useful to allow strparser to init sockets before the read_sock callback has been established. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Generalize strparserTom Herbert2017-08-011-126/+187
| | | | | | | | | | | Generalize strparser from more than just being used in conjunction with read_sock. strparser will also be used in the send path with zero proxy. The primary change is to create strp_process function that performs the critical processing on skbs. The documentation is also updated to reflect the new uses. Signed-off-by: Tom Herbert <tom@quantonium.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: destroy workqueue on module exitWANG Cong2017-03-031-0/+1
| | | | | | | Fixes: 43a0c6751a32 ("strparser: Stream parser for messages") Cc: Tom Herbert <tom@herbertland.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Propagate correct error code in strp_recv()Geert Uytterhoeven2016-10-121-1/+1
| | | | | | | | | | | | | | With m68k-linux-gnu-gcc-4.1: net/strparser/strparser.c: In function ‘strp_recv’: net/strparser/strparser.c:98: warning: ‘err’ may be used uninitialized in this function Pass "len" (which is an error code when negative) instead of the uninitialized "err" variable to fix this. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* kcm: Remove TCP specific references from kcm and strparserTom Herbert2016-08-281-19/+29
| | | | | | | | | | kcm and strparser need to work with any type of stream socket not just TCP. Eliminate references to TCP and call generic proto_ops functions of read_sock and peek_len. Also in strp_init check if the socket support the proto_ops read_sock and peek_len. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Queue work when being unpausedTom Herbert2016-08-231-0/+11
| | | | | | | | When the upper layer unpauses a stream parser connection we need to queue rx_work to make sure no events are missed. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: strparser: fix strparser sk_user_data checkDave Watson2016-08-221-3/+0
| | | | | | | | | | | | sk_user_data mismatch between what kcm expects (psock) and what strparser expects (strparser). Queued rx_work, for example calling strp_check_rcv after socket buffer changes, will never complete. sk_user_data is unused in strparser, so just remove the check. Signed-off-by: Dave Watson <davejwatson@fb.com> Acked-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Stream parser for messagesTom Herbert2016-08-173-0/+497
This patch introduces a utility for parsing application layer protocol messages in a TCP stream. This is a generalization of the mechanism implemented of Kernel Connection Multiplexor. The API includes a context structure, a set of callbacks, utility functions, and a data ready function. A stream parser instance is defined by a strparse structure that is bound to a TCP socket. The function to initialize the structure is: int strp_init(struct strparser *strp, struct sock *csk, struct strp_callbacks *cb); csk is the TCP socket being bound to and cb are the parser callbacks. The upper layer calls strp_tcp_data_ready when data is ready on the lower socket for strparser to process. This should be called from a data_ready callback that is set on the socket: void strp_tcp_data_ready(struct strparser *strp); A parser is bound to a TCP socket by setting data_ready function to strp_tcp_data_ready so that all receive indications on the socket go through the parser. This is assumes that sk_user_data is set to the strparser structure. There are four callbacks. - parse_msg is called to parse the message (returns length or error). - rcv_msg is called when a complete message has been received - read_sock_done is called when data_ready function exits - abort_parser is called to abort the parser The input to parse_msg is an skbuff which contains next message under construction. The backend processing of parse_msg will parse the application layer protocol headers to determine the length of the message in the stream. The possible return values are: >0 : indicates length of successfully parsed message 0 : indicates more data must be received to parse the message -ESTRPIPE : current message should not be processed by the kernel, return control of the socket to userspace which can proceed to read the messages itself other < 0 : Error is parsing, give control back to userspace assuming that synchronzation is lost and the stream is unrecoverable (application expected to close TCP socket) In the case of error return (< 0) strparse will stop the parser and report and error to userspace. The application must deal with the error. To handle the error the strparser is unbound from the TCP socket. If the error indicates that the stream TCP socket is at recoverable point (ESTRPIPE) then the application can read the TCP socket to process the stream. Once the application has dealt with the exceptions in the stream, it may again bind the socket to a strparser to continue data operations. Note that ENODATA may be returned to the application. In this case parse_msg returned -ESTRPIPE, however strparser was unable to maintain synchronization of the stream (i.e. some of the message in question was already read by the parser). strp_pause and strp_unpause are used to provide flow control. For instance, if rcv_msg is called but the upper layer can't immediately consume the message it can hold the message and pause strparser. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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