mirror of https://github.com/mkerrisk/man-pages
bpf-helpers.7: Refresh against Linux 5.0-rc8
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk
parent
d1a719857b
commit
2223d7df7e
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@ -28,18 +28,14 @@
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.\" located in file include/uapi/linux/bpf.h of the Linux kernel sources
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.\" (helpers description), and from scripts/bpf_helpers_doc.py in the same
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.\" repository (header and footer).
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.
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.TH BPF-HELPERS 7 "" "" ""
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.SH NAME
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BPF-HELPERS \- list of eBPF helper functions
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.
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.nr rst2man-indent-level 0
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.
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.de1 rstReportMargin
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\\$1 \\n[an-margin]
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level \\n[rst2man-indent-level]
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level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
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-
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\\n[rst2man-indent0]
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\\n[rst2man-indent1]
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\\n[rst2man-indent2]
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@ -135,6 +131,20 @@ Delete entry with \fIkey\fP from \fImap\fP\&.
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBint bpf_map_push_elem(struct bpf_map *\fP\fImap\fP\fB, const void *\fP\fIvalue\fP\fB, u64\fP \fIflags\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Push an element \fIvalue\fP in \fImap\fP\&. \fIflags\fP is one of:
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.sp
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\fBBPF_EXIST\fP
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If the queue/stack is full, the oldest element is removed to
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make room for this.
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBint bpf_probe_read(void *\fP\fIdst\fP\fB, u32\fP \fIsize\fP\fB, const void *\fP\fIsrc\fP\fB)\fP
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.INDENT 7.0
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.TP
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@ -1240,7 +1250,6 @@ the following snippet:
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.ft C
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SEC("kprobe/sys_open")
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void bpf_sys_open(struct pt_regs *ctx)
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{
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char buf[PATHLEN]; // PATHLEN is defined to 256
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int res = bpf_probe_read_str(buf, sizeof(buf),
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ctx\->di);
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@ -1249,7 +1258,6 @@ void bpf_sys_open(struct pt_regs *ctx)
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// userspace via bpf_perf_event_output(); we
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// can use res (the string length) as event
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// size, after checking its boundaries.
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}
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.ft P
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.fi
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.UNINDENT
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@ -1329,7 +1337,6 @@ Set the full hash for \fIskb\fP (set the field \fIskb\fP\fB\->hash\fP)
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to value \fIhash\fP\&.
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.TP
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.B Return
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0
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.UNINDENT
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.TP
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.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
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@ -1363,7 +1370,7 @@ It supports the following \fIlevel\fPs:
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBint bpf_skb_adjust_room(struct sk_buff *\fP\fIskb\fP\fB, u32\fP \fIlen_diff\fP\fB, u32\fP \fImode\fP\fB, u64\fP \fIflags\fP\fB)\fP
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.B \fBint bpf_skb_adjust_room(struct sk_buff *\fP\fIskb\fP\fB, s32\fP \fIlen_diff\fP\fB, u32\fP \fImode\fP\fB, u64\fP \fIflags\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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@ -1615,7 +1622,6 @@ the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
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x86 architecture is the only one to support this feature.
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.TP
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.B Return
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0
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.UNINDENT
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.TP
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.B \fBint bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *\fP\fIbpf_sock\fP\fB, int\fP \fIargval\fP\fB)\fP
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@ -1724,7 +1730,6 @@ a non\-zero value, this is not a problem because data is not
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being buffered for \fIbytes\fP and is sent as it is received.
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.TP
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.B Return
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0
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.UNINDENT
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.TP
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.B \fBint bpf_msg_cork_bytes(struct sk_msg_buff *\fP\fImsg\fP\fB, u32\fP \fIbytes\fP\fB)\fP
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@ -1746,7 +1751,6 @@ prevent the eBPF program to be called again until \fIbytes\fP have
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been accumulated.
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.TP
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.B Return
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0
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.UNINDENT
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.TP
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.B \fBint bpf_msg_pull_data(struct sk_msg_buff *\fP\fImsg\fP\fB, u32\fP \fIstart\fP\fB, u32\fP \fIend\fP\fB, u64\fP \fIflags\fP\fB)\fP
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@ -2141,8 +2145,8 @@ report a successfully decoded key press with \fIscancode\fP,
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translated to a keycode using the rc keymap, and reported as
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an input key down event. After a period a key up event is
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generated. This period can be extended by calling either
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\fBbpf_rc_keydown\fP () again with the same values, or calling
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\fBbpf_rc_repeat\fP ().
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\fBbpf_rc_keydown\fP() again with the same values, or calling
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\fBbpf_rc_repeat\fP().
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.sp
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Some protocols include a toggle bit, in case the button was
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released and pressed again between consecutive scancodes.
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@ -2158,7 +2162,6 @@ the \fBCONFIG_BPF_LIRC_MODE2\fP configuration option set to
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"\fBy\fP".
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.TP
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.B Return
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0
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.UNINDENT
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.TP
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.B \fBint bpf_rc_repeat(void *\fP\fIctx\fP\fB)\fP
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@ -2181,7 +2184,6 @@ the \fBCONFIG_BPF_LIRC_MODE2\fP configuration option set to
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"\fBy\fP".
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.TP
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.B Return
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0
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.UNINDENT
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.TP
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.B \fBuint64_t bpf_skb_cgroup_id(struct sk_buff *\fP\fIskb\fP\fB)\fP
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@ -2244,29 +2246,201 @@ by the \fImap\fP argument.
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The \fIflags\fP meaning is specific for each map type,
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and has to be 0 for cgroup local storage.
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.sp
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Depending on the bpf program type, a local storage area
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can be shared between multiple instances of the bpf program,
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Depending on the BPF program type, a local storage area
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can be shared between multiple instances of the BPF program,
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running simultaneously.
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.sp
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A user should care about the synchronization by himself.
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For example, by using the BPF_STX_XADD instruction to alter
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For example, by using the \fBBPF_STX_XADD\fP instruction to alter
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the shared data.
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.TP
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.B Return
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Pointer to the local storage area.
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A pointer to the local storage area.
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.UNINDENT
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.TP
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.B \fBint bpf_sk_select_reuseport(struct sk_reuseport_md *\fP\fIreuse\fP\fB, struct bpf_map *\fP\fImap\fP\fB, void *\fP\fIkey\fP\fB, u64\fP \fIflags\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Select a SO_REUSEPORT sk from a BPF_MAP_TYPE_REUSEPORT_ARRAY map
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It checks the selected sk is matching the incoming
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request in the skb.
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Select a \fBSO_REUSEPORT\fP socket from a
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\fBBPF_MAP_TYPE_REUSEPORT_ARRAY\fP \fImap\fP\&.
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It checks the selected socket is matching the incoming
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request in the socket buffer.
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBstruct bpf_sock *bpf_sk_lookup_tcp(void *\fP\fIctx\fP\fB, struct bpf_sock_tuple *\fP\fItuple\fP\fB, u32\fP \fItuple_size\fP\fB, u64\fP \fInetns\fP\fB, u64\fP \fIflags\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Look for TCP socket matching \fItuple\fP, optionally in a child
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network namespace \fInetns\fP\&. The return value must be checked,
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and if non\-\fBNULL\fP, released via \fBbpf_sk_release\fP().
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.sp
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The \fIctx\fP should point to the context of the program, such as
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the skb or socket (depending on the hook in use). This is used
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to determine the base network namespace for the lookup.
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.sp
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\fItuple_size\fP must be one of:
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.INDENT 7.0
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.TP
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.B \fBsizeof\fP(\fItuple\fP\fB\->ipv4\fP)
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Look for an IPv4 socket.
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.TP
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.B \fBsizeof\fP(\fItuple\fP\fB\->ipv6\fP)
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Look for an IPv6 socket.
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.UNINDENT
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.sp
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If the \fInetns\fP is a negative signed 32\-bit integer, then the
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socket lookup table in the netns associated with the \fIctx\fP will
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will be used. For the TC hooks, this is the netns of the device
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in the skb. For socket hooks, this is the netns of the socket.
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If \fInetns\fP is any other signed 32\-bit value greater than or
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equal to zero then it specifies the ID of the netns relative to
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the netns associated with the \fIctx\fP\&. \fInetns\fP values beyond the
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range of 32\-bit integers are reserved for future use.
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.sp
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All values for \fIflags\fP are reserved for future usage, and must
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be left at zero.
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.sp
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This helper is available only if the kernel was compiled with
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\fBCONFIG_NET\fP configuration option.
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.TP
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.B Return
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Pointer to \fBstruct bpf_sock\fP, or \fBNULL\fP in case of failure.
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For sockets with reuseport option, the \fBstruct bpf_sock\fP
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result is from \fBreuse\->socks\fP[] using the hash of the tuple.
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.UNINDENT
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.TP
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.B \fBstruct bpf_sock *bpf_sk_lookup_udp(void *\fP\fIctx\fP\fB, struct bpf_sock_tuple *\fP\fItuple\fP\fB, u32\fP \fItuple_size\fP\fB, u64\fP \fInetns\fP\fB, u64\fP \fIflags\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Look for UDP socket matching \fItuple\fP, optionally in a child
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network namespace \fInetns\fP\&. The return value must be checked,
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and if non\-\fBNULL\fP, released via \fBbpf_sk_release\fP().
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.sp
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The \fIctx\fP should point to the context of the program, such as
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the skb or socket (depending on the hook in use). This is used
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to determine the base network namespace for the lookup.
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.sp
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\fItuple_size\fP must be one of:
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.INDENT 7.0
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.TP
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.B \fBsizeof\fP(\fItuple\fP\fB\->ipv4\fP)
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Look for an IPv4 socket.
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.TP
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.B \fBsizeof\fP(\fItuple\fP\fB\->ipv6\fP)
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Look for an IPv6 socket.
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.UNINDENT
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.sp
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If the \fInetns\fP is a negative signed 32\-bit integer, then the
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socket lookup table in the netns associated with the \fIctx\fP will
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will be used. For the TC hooks, this is the netns of the device
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in the skb. For socket hooks, this is the netns of the socket.
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If \fInetns\fP is any other signed 32\-bit value greater than or
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equal to zero then it specifies the ID of the netns relative to
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the netns associated with the \fIctx\fP\&. \fInetns\fP values beyond the
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range of 32\-bit integers are reserved for future use.
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.sp
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All values for \fIflags\fP are reserved for future usage, and must
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be left at zero.
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.sp
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This helper is available only if the kernel was compiled with
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\fBCONFIG_NET\fP configuration option.
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.TP
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.B Return
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Pointer to \fBstruct bpf_sock\fP, or \fBNULL\fP in case of failure.
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For sockets with reuseport option, the \fBstruct bpf_sock\fP
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result is from \fBreuse\->socks\fP[] using the hash of the tuple.
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.UNINDENT
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.TP
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.B \fBint bpf_sk_release(struct bpf_sock *\fP\fIsock\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Release the reference held by \fIsock\fP\&. \fIsock\fP must be a
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non\-\fBNULL\fP pointer that was returned from
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\fBbpf_sk_lookup_xxx\fP().
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBint bpf_map_pop_elem(struct bpf_map *\fP\fImap\fP\fB, void *\fP\fIvalue\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Pop an element from \fImap\fP\&.
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBint bpf_map_peek_elem(struct bpf_map *\fP\fImap\fP\fB, void *\fP\fIvalue\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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Get an element from \fImap\fP without removing it.
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.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
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.INDENT 7.0
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.TP
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.B Description
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For socket policies, insert \fIlen\fP bytes into \fImsg\fP at offset
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\fIstart\fP\&.
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.sp
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If a program of type \fBBPF_PROG_TYPE_SK_MSG\fP is run on a
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\fImsg\fP it may want to insert metadata or options into the \fImsg\fP\&.
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This can later be read and used by any of the lower layer BPF
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hooks.
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.sp
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This helper may fail if under memory pressure (a malloc
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fails) in these cases BPF programs will get an appropriate
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error and BPF programs will need to handle them.
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.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
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.INDENT 7.0
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.TP
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.B Description
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Will remove \fIpop\fP bytes from a \fImsg\fP starting at byte \fIstart\fP\&.
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This may result in \fBENOMEM\fP errors under certain situations if
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an allocation and copy are required due to a full ring buffer.
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However, the helper will try to avoid doing the allocation
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if possible. Other errors can occur if input parameters are
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invalid either due to \fIstart\fP byte not being valid part of \fImsg\fP
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payload and/or \fIpop\fP value being to large.
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.TP
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.B Return
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0 on success, or a negative error in case of failure.
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.UNINDENT
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.TP
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.B \fBint bpf_rc_pointer_rel(void *\fP\fIctx\fP\fB, s32\fP \fIrel_x\fP\fB, s32\fP \fIrel_y\fP\fB)\fP
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.INDENT 7.0
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.TP
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.B Description
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This helper is used in programs implementing IR decoding, to
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report a successfully decoded pointer movement.
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.sp
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The \fIctx\fP should point to the lirc sample as passed into
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the program.
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.sp
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This helper is only available is the kernel was compiled with
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the \fBCONFIG_BPF_LIRC_MODE2\fP configuration option set to
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"\fBy\fP".
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.TP
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.B Return
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.UNINDENT
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.UNINDENT
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.SH EXAMPLES
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.sp
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@ -2353,4 +2527,3 @@ pointers for network processing are listed in function
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\fBsocket\fP(7),
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\fBtc\-bpf\fP(8)
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.\" Generated by docutils manpage writer.
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.
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