193 lines
7.7 KiB
Groff
193 lines
7.7 KiB
Groff
.\" Man page generated from reStructuredText.
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.
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.TH "SYNCTHING-LOCALDISCO" "7" "November 21, 2015" "v0.12" "Syncthing"
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.SH NAME
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syncthing-localdisco \- Local Discovery Protocol v3
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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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..
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.de1 INDENT
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.\" .rstReportMargin pre:
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. RS \\$1
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. nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin]
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. nr rst2man-indent-level +1
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.\" .rstReportMargin post:
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..
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.de UNINDENT
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. RE
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.\" indent \\n[an-margin]
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.\" old: \\n[rst2man-indent\\n[rst2man-indent-level]]
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.nr rst2man-indent-level -1
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.\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
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.in \\n[rst2man-indent\\n[rst2man-indent-level]]u
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..
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.SH MODE OF OPERATION
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.sp
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Each participating device periodically sends an Announcement packet. It also
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keeps a table of the announcements it has seen. There is no way to solicit a
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reply; the only message type is Announcement.
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.sp
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On multihomed hosts the announcement packets should be sent on each interface
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on which Syncthing will accept connections.
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.sp
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For IPv4, the Announcement packet is broadcast either to the link\-specific
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broadcast address, or to the generic link\-local broadcast address
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\fB255.255.255.255\fP, with destination port 21027.
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.sp
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For IPv6, the Announcement packet is multicast to the transient link\-local
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multicast address \fB[ff12::8384]\fP, with destination port 21027.
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.sp
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It is recommended that local discovery Announcement packets be sent on a 30 to
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60 second interval, possibly with immediate transmissions when a previously
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unknown device is discovered.
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.SH DEVICE ID
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.sp
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The device ID is the SHA\-256 (32 bytes) of the device X.509 certificate. See
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device\-ids in the Syncthing documentation.
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.SH ANNOUNCEMENT PACKET
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.sp
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The Announcement packet has the following structure:
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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Announce Structure:
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Magic |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e Device Structure \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Number of Extra Devices |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e Zero or more Device Structures \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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Device Structure:
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Length of ID |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e ID (variable length) \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Number of Addresses |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e Zero or more Address Structures \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Number of Relays |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e Zero or more Relay Structures \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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Address Structure:
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Length of URL |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e URL (variable length) \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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Relay Structure:
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Length of URL |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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/ /
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\e URL (variable length) \e
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/ /
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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| Latency |
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+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+\-+
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.sp
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The corresponding XDR representation is as follows (see
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\fI\%RFC4506\fP <\fBhttp://tools.ietf.org/html/rfc4506\fP> for the XDR format):
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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struct Announcement {
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unsigned int Magic;
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Device This;
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Device Extra<>;
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}
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struct Device {
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opaque ID<32>;
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Address Addresses<16>;
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Relay Relays<16>;
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}
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struct Address {
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string URL<2083>;
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}
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struct Relay {
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string URL<2083>;
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int Latency;
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}
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.sp
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In the \fBAnnounce\fP structure field \fBMagic\fP is used to ensure
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a correct datagram was received and MUST be equal to \fB0x9D79BC40\fP\&.
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.sp
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The first Device structure contains information about the sending
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device. The following zero or more Extra devices contain information
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about other devices known to the sending device.
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.sp
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In the \fBDevice\fP structure, field \fBDeviceID\fP is the SHA\-256 (32
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bytes) of the device X.509 certificate, as explained in section \fIDevice
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ID\fP\&.
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.sp
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For each \fBAddress\fP and \fBRelay\fP the \fBURL\fP field contains the actual
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target address. Direct connections (the \fBAddress\fP list) will
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typically have the \fBtcp://\fP scheme. Relay connections will typically use the
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\fBrelay://\fP scheme.
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.sp
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The \fBLatency\fP field contains the approximate latency for a TCP handshake
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(i.e. three packet round trips) between the other device and the relay, in
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milliseconds.
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.SH AUTHOR
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The Syncthing Authors
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.SH COPYRIGHT
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2015, The Syncthing Authors
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.\" Generated by docutils manpage writer.
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.
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