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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2020-04-16 13:45:41 +0200 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2020-04-16 13:45:41 +0200 |
| commit | 4e2b112c91b63a183d2608606b35c6e1c04c55f6 (patch) | |
| tree | 6fe7fb7eab2693404d92ce0f403127f558d9ffce /man7 | |
| parent | d407f83e5f612a644846c2c269ddbc5ab39cf323 (diff) | |
| download | man-pages-4e2b112c91b63a183d2608606b35c6e1c04c55f6.tar.gz | |
bpf-helpers.7: Sync against Linux 5.7-rc1
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Diffstat (limited to 'man7')
| -rw-r--r-- | man7/bpf-helpers.7 | 418 |
1 files changed, 343 insertions, 75 deletions
diff --git a/man7/bpf-helpers.7 b/man7/bpf-helpers.7 index 02c1907c15..a23243abff 100644 --- a/man7/bpf-helpers.7 +++ b/man7/bpf-helpers.7 @@ -1,6 +1,6 @@ .\" Man page generated from reStructuredText. . -.TH BPF-HELPERS 7 2019-11-19 "Linux" "Linux Programmer's Manual" +.TH BPF-HELPERS 7 "" "" "" .SH NAME BPF-HELPERS \- list of eBPF helper functions . @@ -32,17 +32,17 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] .. .\" Copyright (C) All BPF authors and contributors from 2014 to present. .\" See git log include/uapi/linux/bpf.h in kernel tree for details. -.\" +.\" .\" %%%LICENSE_START(VERBATIM) .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. -.\" +.\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. -.\" +.\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from @@ -50,15 +50,16 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. -.\" +.\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" %%%LICENSE_END -.\" +.\" .\" Please do not edit this file. It was generated from the documentation .\" located in file include/uapi/linux/bpf.h of the Linux kernel sources .\" (helpers description), and from scripts/bpf_helpers_doc.py in the same .\" repository (header and footer). +. .SH DESCRIPTION .sp The extended Berkeley Packet Filter (eBPF) subsystem consists in programs @@ -135,12 +136,15 @@ Delete entry with \fIkey\fP from \fImap\fP\&. 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_probe_read(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIsrc\fP\fB)\fP +.B \fBint bpf_probe_read(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP .INDENT 7.0 .TP .B Description For tracing programs, safely attempt to read \fIsize\fP bytes from -address \fIsrc\fP and store the data in \fIdst\fP\&. +kernel space address \fIunsafe_ptr\fP and store the data in \fIdst\fP\&. +.sp +Generally, use bpf_probe_read_user() or bpf_probe_read_kernel() +instead. .TP .B Return 0 on success, or a negative error in case of failure. @@ -432,7 +436,7 @@ A 64\-bit integer containing the current GID and UID, and created as such: \fIcurrent_gid\fP \fB<< 32 |\fP \fIcurrent_uid\fP\&. .UNINDENT .TP -.B \fBint bpf_get_current_comm(char *\fP\fIbuf\fP\fB, u32\fP \fIsize_of_buf\fP\fB)\fP +.B \fBint bpf_get_current_comm(void *\fP\fIbuf\fP\fB, u32\fP \fIsize_of_buf\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -672,9 +676,9 @@ is present, egress path otherwise). Currently, XDP only supports redirection to the egress interface, and accepts no flag at all. .sp -The same effect can be attained with the more generic -\fBbpf_redirect_map\fP(), which requires specific maps to be -used but offers better performance. +The same effect can also be attained with the more generic +\fBbpf_redirect_map\fP(), which uses a BPF map to store the +redirect target instead of providing it directly to the helper. .TP .B Return For XDP, the helper returns \fBXDP_REDIRECT\fP on success or @@ -711,7 +715,7 @@ The realm of the route for the packet associated to \fIskb\fP, or 0 if none was found. .UNINDENT .TP -.B \fBint bpf_perf_event_output(struct pt_regs *\fP\fIctx\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u64\fP \fIflags\fP\fB, void *\fP\fIdata\fP\fB, u64\fP \fIsize\fP\fB)\fP +.B \fBint bpf_perf_event_output(void *\fP\fIctx\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u64\fP \fIflags\fP\fB, void *\fP\fIdata\fP\fB, u64\fP \fIsize\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -764,7 +768,7 @@ A combination of both. 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_skb_load_bytes(const struct sk_buff *\fP\fIskb\fP\fB, u32\fP \fIoffset\fP\fB, void *\fP\fIto\fP\fB, u32\fP \fIlen\fP\fB)\fP +.B \fBint bpf_skb_load_bytes(const void *\fP\fIskb\fP\fB, u32\fP \fIoffset\fP\fB, void *\fP\fIto\fP\fB, u32\fP \fIlen\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -785,7 +789,7 @@ at once from a packet into the eBPF stack. 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_get_stackid(struct pt_regs *\fP\fIctx\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u64\fP \fIflags\fP\fB)\fP +.B \fBint bpf_get_stackid(void *\fP\fIctx\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u64\fP \fIflags\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -876,7 +880,7 @@ The checksum result, or a negative error code in case of failure. .UNINDENT .TP -.B \fBint bpf_skb_get_tunnel_opt(struct sk_buff *\fP\fIskb\fP\fB, u8 *\fP\fIopt\fP\fB, u32\fP \fIsize\fP\fB)\fP +.B \fBint bpf_skb_get_tunnel_opt(struct sk_buff *\fP\fIskb\fP\fB, void *\fP\fIopt\fP\fB, u32\fP \fIsize\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -898,7 +902,7 @@ headers. The size of the option data retrieved. .UNINDENT .TP -.B \fBint bpf_skb_set_tunnel_opt(struct sk_buff *\fP\fIskb\fP\fB, u8 *\fP\fIopt\fP\fB, u32\fP \fIsize\fP\fB)\fP +.B \fBint bpf_skb_set_tunnel_opt(struct sk_buff *\fP\fIskb\fP\fB, void *\fP\fIopt\fP\fB, u32\fP \fIsize\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -1220,52 +1224,16 @@ direct packet access. 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_probe_read_str(void *\fP\fIdst\fP\fB, int\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP +.B \fBint bpf_probe_read_str(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP .INDENT 7.0 .TP .B Description -Copy a NUL terminated string from an unsafe address -\fIunsafe_ptr\fP to \fIdst\fP\&. The \fIsize\fP should include the -terminating NUL byte. In case the string length is smaller than -\fIsize\fP, the target is not padded with further NUL bytes. If the -string length is larger than \fIsize\fP, just \fIsize\fP\-1 bytes are -copied and the last byte is set to NUL. -.sp -On success, the length of the copied string is returned. This -makes this helper useful in tracing programs for reading -strings, and more importantly to get its length at runtime. See -the following snippet: -.INDENT 7.0 -.INDENT 3.5 -.sp -.nf -.ft C -SEC("kprobe/sys_open") -void bpf_sys_open(struct pt_regs *ctx) -{ - char buf[PATHLEN]; // PATHLEN is defined to 256 - int res = bpf_probe_read_str(buf, sizeof(buf), - ctx\->di); - - // Consume buf, for example push it to - // userspace via bpf_perf_event_output(); we - // can use res (the string length) as event - // size, after checking its boundaries. -} -.ft P -.fi -.UNINDENT -.UNINDENT +Copy a NUL terminated string from an unsafe kernel address +\fIunsafe_ptr\fP to \fIdst\fP\&. See bpf_probe_read_kernel_str() for +more details. .sp -In comparison, using \fBbpf_probe_read()\fP helper here instead -to read the string would require to estimate the length at -compile time, and would often result in copying more memory -than necessary. -.sp -Another useful use case is when parsing individual process -arguments or individual environment variables navigating -\fIcurrent\fP\fB\->mm\->arg_start\fP and \fIcurrent\fP\fB\->mm\->env_start\fP: using this helper and the return value, -one can quickly iterate at the right offset of the memory area. +Generally, use bpf_probe_read_user_str() or bpf_probe_read_kernel_str() +instead. .TP .B Return On success, the strictly positive length of the string, @@ -1334,7 +1302,7 @@ to value \fIhash\fP\&. 0 .UNINDENT .TP -.B \fBint bpf_setsockopt(struct bpf_sock_ops *\fP\fIbpf_socket\fP\fB, int\fP \fIlevel\fP\fB, int\fP \fIoptname\fP\fB, char *\fP\fIoptval\fP\fB, int\fP \fIoptlen\fP\fB)\fP +.B \fBint bpf_setsockopt(struct bpf_sock_ops *\fP\fIbpf_socket\fP\fB, int\fP \fIlevel\fP\fB, int\fP \fIoptname\fP\fB, void *\fP\fIoptval\fP\fB, int\fP \fIoptlen\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -1429,16 +1397,21 @@ one of the XDP program return codes up to XDP_TX, as chosen by the caller. Any higher bits in the \fIflags\fP argument must be unset. .sp -When used to redirect packets to net devices, this helper -provides a high performance increase over \fBbpf_redirect\fP(). -This is due to various implementation details of the underlying -mechanisms, one of which is the fact that \fBbpf_redirect_map\fP() tries to send packet as a "bulk" to the device. +See also bpf_redirect(), which only supports redirecting to an +ifindex, but doesn\(aqt require a map to do so. .TP .B Return -\fBXDP_REDIRECT\fP on success, or \fBXDP_ABORTED\fP on error. +\fBXDP_REDIRECT\fP on success, or the value of the two lower bits +of the +.nf +** +.fi +flags* argument on error. +.IP "System Message: WARNING/2 (/tmp/bpf-helpers.rst:, line 1105)" +Inline strong start\-string without end\-string. .UNINDENT .TP -.B \fBint bpf_sk_redirect_map(struct bpf_map *\fP\fImap\fP\fB, u32\fP \fIkey\fP\fB, u64\fP \fIflags\fP\fB)\fP +.B \fBint bpf_sk_redirect_map(struct sk_buff *\fP\fIskb\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u32\fP \fIkey\fP\fB, u64\fP \fIflags\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -1587,7 +1560,7 @@ more details). 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_getsockopt(struct bpf_sock_ops *\fP\fIbpf_socket\fP\fB, int\fP \fIlevel\fP\fB, int\fP \fIoptname\fP\fB, char *\fP\fIoptval\fP\fB, int\fP \fIoptlen\fP\fB)\fP +.B \fBint bpf_getsockopt(struct bpf_sock_ops *\fP\fIbpf_socket\fP\fB, int\fP \fIlevel\fP\fB, int\fP \fIoptname\fP\fB, void *\fP\fIoptval\fP\fB, int\fP \fIoptlen\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -1878,7 +1851,7 @@ This helper is available only if the kernel was compiled with 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_get_stack(struct pt_regs *\fP\fIregs\fP\fB, void *\fP\fIbuf\fP\fB, u32\fP \fIsize\fP\fB, u64\fP \fIflags\fP\fB)\fP +.B \fBint bpf_get_stack(void *\fP\fIctx\fP\fB, void *\fP\fIbuf\fP\fB, u32\fP \fIsize\fP\fB, u64\fP \fIflags\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -1924,7 +1897,7 @@ A non\-negative value equal to or less than \fIsize\fP on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_skb_load_bytes_relative(const struct sk_buff *\fP\fIskb\fP\fB, u32\fP \fIoffset\fP\fB, void *\fP\fIto\fP\fB, u32\fP \fIlen\fP\fB, u32\fP \fIstart_header\fP\fB)\fP +.B \fBint bpf_skb_load_bytes_relative(const void *\fP\fIskb\fP\fB, u32\fP \fIoffset\fP\fB, void *\fP\fIto\fP\fB, u32\fP \fIlen\fP\fB, u32\fP \fIstart_header\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -1996,7 +1969,7 @@ packet is not forwarded or needs assist from full stack .UNINDENT .UNINDENT .TP -.B \fBint bpf_sock_hash_update(struct bpf_sock_ops_kern *\fP\fIskops\fP\fB, struct bpf_map *\fP\fImap\fP\fB, void *\fP\fIkey\fP\fB, u64\fP \fIflags\fP\fB)\fP +.B \fBint bpf_sock_hash_update(struct bpf_sock_ops *\fP\fIskops\fP\fB, struct bpf_map *\fP\fImap\fP\fB, void *\fP\fIkey\fP\fB, u64\fP \fIflags\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -2455,7 +2428,7 @@ Get an element from \fImap\fP without removing it. 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_msg_push_data(struct sk_buff *\fP\fIskb\fP\fB, u32\fP \fIstart\fP\fB, u32\fP \fIlen\fP\fB, u64\fP \fIflags\fP\fB)\fP +.B \fBint bpf_msg_push_data(struct sk_msg_buff *\fP\fImsg\fP\fB, u32\fP \fIstart\fP\fB, u32\fP \fIlen\fP\fB, u64\fP \fIflags\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -2475,11 +2448,11 @@ error and BPF programs will need to handle them. 0 on success, or a negative error in case of failure. .UNINDENT .TP -.B \fBint bpf_msg_pop_data(struct sk_msg_buff *\fP\fImsg\fP\fB, u32\fP \fIstart\fP\fB, u32\fP \fIpop\fP\fB, u64\fP \fIflags\fP\fB)\fP +.B \fBint bpf_msg_pop_data(struct sk_msg_buff *\fP\fImsg\fP\fB, u32\fP \fIstart\fP\fB, u32\fP \fIlen\fP\fB, u64\fP \fIflags\fP\fB)\fP .INDENT 7.0 .TP .B Description -Will remove \fIpop\fP bytes from a \fImsg\fP starting at byte \fIstart\fP\&. +Will remove \fIlen\fP bytes from a \fImsg\fP starting at byte \fIstart\fP\&. This may result in \fBENOMEM\fP errors under certain situations if an allocation and copy are required due to a full ring buffer. However, the helper will try to avoid doing the allocation @@ -2613,7 +2586,7 @@ A \fBstruct bpf_tcp_sock\fP pointer on success, or \fBNULL\fP in case of failure. .UNINDENT .TP -.B \fBint bpf_skb_ecn_set_ce(struct sk_buf *\fP\fIskb\fP\fB)\fP +.B \fBint bpf_skb_ecn_set_ce(struct sk_buff *\fP\fIskb\fP\fB)\fP .INDENT 7.0 .TP .B Description @@ -2869,7 +2842,8 @@ Delete a bpf\-local\-storage from a \fIsk\fP\&. .INDENT 7.0 .TP .B Description -Send signal \fIsig\fP to the current task. +Send signal \fIsig\fP to the process of the current task. +The signal may be delivered to any of this process\(aqs threads. .TP .B Return 0 on success or successfully queued. @@ -2912,6 +2886,300 @@ On failure, the returned value is one of the following: .sp \fB\-EPROTONOSUPPORT\fP IP packet version is not 4 or 6 .UNINDENT +.TP +.B \fBint bpf_skb_output(void *\fP\fIctx\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u64\fP \fIflags\fP\fB, void *\fP\fIdata\fP\fB, u64\fP \fIsize\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Write raw \fIdata\fP blob into a special BPF perf event held by +\fImap\fP of type \fBBPF_MAP_TYPE_PERF_EVENT_ARRAY\fP\&. This perf +event must have the following attributes: \fBPERF_SAMPLE_RAW\fP +as \fBsample_type\fP, \fBPERF_TYPE_SOFTWARE\fP as \fBtype\fP, and +\fBPERF_COUNT_SW_BPF_OUTPUT\fP as \fBconfig\fP\&. +.sp +The \fIflags\fP are used to indicate the index in \fImap\fP for which +the value must be put, masked with \fBBPF_F_INDEX_MASK\fP\&. +Alternatively, \fIflags\fP can be set to \fBBPF_F_CURRENT_CPU\fP +to indicate that the index of the current CPU core should be +used. +.sp +The value to write, of \fIsize\fP, is passed through eBPF stack and +pointed by \fIdata\fP\&. +.sp +\fIctx\fP is a pointer to in\-kernel struct sk_buff. +.sp +This helper is similar to \fBbpf_perf_event_output\fP() but +restricted to raw_tracepoint bpf programs. +.TP +.B Return +0 on success, or a negative error in case of failure. +.UNINDENT +.TP +.B \fBint bpf_probe_read_user(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Safely attempt to read \fIsize\fP bytes from user space address +\fIunsafe_ptr\fP and store the data in \fIdst\fP\&. +.TP +.B Return +0 on success, or a negative error in case of failure. +.UNINDENT +.TP +.B \fBint bpf_probe_read_kernel(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Safely attempt to read \fIsize\fP bytes from kernel space address +\fIunsafe_ptr\fP and store the data in \fIdst\fP\&. +.TP +.B Return +0 on success, or a negative error in case of failure. +.UNINDENT +.TP +.B \fBint bpf_probe_read_user_str(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Copy a NUL terminated string from an unsafe user address +\fIunsafe_ptr\fP to \fIdst\fP\&. The \fIsize\fP should include the +terminating NUL byte. In case the string length is smaller than +\fIsize\fP, the target is not padded with further NUL bytes. If the +string length is larger than \fIsize\fP, just \fIsize\fP\-1 bytes are +copied and the last byte is set to NUL. +.sp +On success, the length of the copied string is returned. This +makes this helper useful in tracing programs for reading +strings, and more importantly to get its length at runtime. See +the following snippet: +.INDENT 7.0 +.INDENT 3.5 +.sp +.nf +.ft C +SEC("kprobe/sys_open") +void bpf_sys_open(struct pt_regs *ctx) +{ + char buf[PATHLEN]; // PATHLEN is defined to 256 + int res = bpf_probe_read_user_str(buf, sizeof(buf), + ctx\->di); + + // Consume buf, for example push it to + // userspace via bpf_perf_event_output(); we + // can use res (the string length) as event + // size, after checking its boundaries. +} +.ft P +.fi +.UNINDENT +.UNINDENT +.sp +In comparison, using \fBbpf_probe_read_user()\fP helper here +instead to read the string would require to estimate the length +at compile time, and would often result in copying more memory +than necessary. +.sp +Another useful use case is when parsing individual process +arguments or individual environment variables navigating +\fIcurrent\fP\fB\->mm\->arg_start\fP and \fIcurrent\fP\fB\->mm\->env_start\fP: using this helper and the return value, +one can quickly iterate at the right offset of the memory area. +.TP +.B Return +On success, the strictly positive length of the string, +including the trailing NUL character. On error, a negative +value. +.UNINDENT +.TP +.B \fBint bpf_probe_read_kernel_str(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIunsafe_ptr\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Copy a NUL terminated string from an unsafe kernel address \fIunsafe_ptr\fP +to \fIdst\fP\&. Same semantics as with bpf_probe_read_user_str() apply. +.TP +.B Return +On success, the strictly positive length of the string, including +the trailing NUL character. On error, a negative value. +.UNINDENT +.TP +.B \fBint bpf_tcp_send_ack(void *\fP\fItp\fP\fB, u32\fP \fIrcv_nxt\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Send out a tcp\-ack. \fItp\fP is the in\-kernel struct tcp_sock. +\fIrcv_nxt\fP is the ack_seq to be sent out. +.TP +.B Return +0 on success, or a negative error in case of failure. +.UNINDENT +.TP +.B \fBint bpf_send_signal_thread(u32\fP \fIsig\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Send signal \fIsig\fP to the thread corresponding to the current task. +.TP +.B Return +0 on success or successfully queued. +.sp +\fB\-EBUSY\fP if work queue under nmi is full. +.sp +\fB\-EINVAL\fP if \fIsig\fP is invalid. +.sp +\fB\-EPERM\fP if no permission to send the \fIsig\fP\&. +.sp +\fB\-EAGAIN\fP if bpf program can try again. +.UNINDENT +.TP +.B \fBu64 bpf_jiffies64(void)\fP +.INDENT 7.0 +.TP +.B Description +Obtain the 64bit jiffies +.TP +.B Return +The 64 bit jiffies +.UNINDENT +.TP +.B \fBint bpf_read_branch_records(struct bpf_perf_event_data *\fP\fIctx\fP\fB, void *\fP\fIbuf\fP\fB, u32\fP \fIsize\fP\fB, u64\fP \fIflags\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +For an eBPF program attached to a perf event, retrieve the +branch records (struct perf_branch_entry) associated to \fIctx\fP +and store it in the buffer pointed by \fIbuf\fP up to size +\fIsize\fP bytes. +.TP +.B Return +On success, number of bytes written to \fIbuf\fP\&. On error, a +negative value. +.sp +The \fIflags\fP can be set to \fBBPF_F_GET_BRANCH_RECORDS_SIZE\fP to +instead return the number of bytes required to store all the +branch entries. If this flag is set, \fIbuf\fP may be NULL. +.sp +\fB\-EINVAL\fP if arguments invalid or \fBsize\fP not a multiple +of sizeof(struct perf_branch_entry). +.sp +\fB\-ENOENT\fP if architecture does not support branch records. +.UNINDENT +.TP +.B \fBint bpf_get_ns_current_pid_tgid(u64\fP \fIdev\fP\fB, u64\fP \fIino\fP\fB, struct bpf_pidns_info *\fP\fInsdata\fP\fB, u32\fP \fIsize\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Returns 0 on success, values for \fIpid\fP and \fItgid\fP as seen from the current +\fInamespace\fP will be returned in \fInsdata\fP\&. +.sp +On failure, the returned value is one of the following: +.sp +\fB\-EINVAL\fP if dev and inum supplied don\(aqt match dev_t and inode number +with nsfs of current task, or if dev conversion to dev_t lost high bits. +.sp +\fB\-ENOENT\fP if pidns does not exists for the current task. +.UNINDENT +.TP +.B \fBint bpf_xdp_output(void *\fP\fIctx\fP\fB, struct bpf_map *\fP\fImap\fP\fB, u64\fP \fIflags\fP\fB, void *\fP\fIdata\fP\fB, u64\fP \fIsize\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Write raw \fIdata\fP blob into a special BPF perf event held by +\fImap\fP of type \fBBPF_MAP_TYPE_PERF_EVENT_ARRAY\fP\&. This perf +event must have the following attributes: \fBPERF_SAMPLE_RAW\fP +as \fBsample_type\fP, \fBPERF_TYPE_SOFTWARE\fP as \fBtype\fP, and +\fBPERF_COUNT_SW_BPF_OUTPUT\fP as \fBconfig\fP\&. +.sp +The \fIflags\fP are used to indicate the index in \fImap\fP for which +the value must be put, masked with \fBBPF_F_INDEX_MASK\fP\&. +Alternatively, \fIflags\fP can be set to \fBBPF_F_CURRENT_CPU\fP +to indicate that the index of the current CPU core should be +used. +.sp +The value to write, of \fIsize\fP, is passed through eBPF stack and +pointed by \fIdata\fP\&. +.sp +\fIctx\fP is a pointer to in\-kernel struct xdp_buff. +.sp +This helper is similar to \fBbpf_perf_eventoutput\fP() but +restricted to raw_tracepoint bpf programs. +.TP +.B Return +0 on success, or a negative error in case of failure. +.UNINDENT +.TP +.B \fBu64 bpf_get_netns_cookie(void *\fP\fIctx\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Retrieve the cookie (generated by the kernel) of the network +namespace the input \fIctx\fP is associated with. The network +namespace cookie remains stable for its lifetime and provides +a global identifier that can be assumed unique. If \fIctx\fP is +NULL, then the helper returns the cookie for the initial +network namespace. The cookie itself is very similar to that +of bpf_get_socket_cookie() helper, but for network namespaces +instead of sockets. +.TP +.B Return +A 8\-byte long opaque number. +.UNINDENT +.TP +.B \fBu64 bpf_get_current_ancestor_cgroup_id(int\fP \fIancestor_level\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Return id of cgroup v2 that is ancestor of the cgroup associated +with the current task at the \fIancestor_level\fP\&. The root cgroup +is at \fIancestor_level\fP zero and each step down the hierarchy +increments the level. If \fIancestor_level\fP == level of cgroup +associated with the current task, then return value will be the +same as that of \fBbpf_get_current_cgroup_id\fP(). +.sp +The helper is useful to implement policies based on cgroups +that are upper in hierarchy than immediate cgroup associated +with the current task. +.sp +The format of returned id and helper limitations are same as in +\fBbpf_get_current_cgroup_id\fP(). +.TP +.B Return +The id is returned or 0 in case the id could not be retrieved. +.UNINDENT +.TP +.B \fBint bpf_sk_assign(struct sk_buff *\fP\fIskb\fP\fB, struct bpf_sock *\fP\fIsk\fP\fB, u64\fP \fIflags\fP\fB)\fP +.INDENT 7.0 +.TP +.B Description +Assign the \fIsk\fP to the \fIskb\fP\&. When combined with appropriate +routing configuration to receive the packet towards the socket, +will cause \fIskb\fP to be delivered to the specified socket. +Subsequent redirection of \fIskb\fP via \fBbpf_redirect\fP(), +\fBbpf_clone_redirect\fP() or other methods outside of BPF may +interfere with successful delivery to the socket. +.sp +This operation is only valid from TC ingress path. +.sp +The \fIflags\fP argument must be zero. +.TP +.B Return +0 on success, or a negative errno in case of failure. +.INDENT 7.0 +.IP \(bu 2 +\fB\-EINVAL\fP Unsupported flags specified. +.IP \(bu 2 +\fB\-ENOENT\fP Socket is unavailable for assignment. +.IP \(bu 2 +\fB\-ENETUNREACH\fP Socket is unreachable (wrong netns). +.IP \(bu 2 +.INDENT 2.0 +.TP +.B \fB\-EOPNOTSUPP\fP Unsupported operation, for example a +call from outside of TC ingress. +.UNINDENT +.IP \(bu 2 +\fB\-ESOCKTNOSUPPORT\fP Socket type not supported (reuseport). +.UNINDENT +.UNINDENT .UNINDENT .SH EXAMPLES .sp |