131 lines
2.2 KiB
Groff
131 lines
2.2 KiB
Groff
.Dd December 13, 2021
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.Dt GETDNSCOFIG 2
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.Os
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.Sh NAME
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.Nm getdnsconfig ,
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.Nm setdnsconfig
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.Nd get and set the kernel DNS resolver list
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.Sh SYNOPSIS
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.In sys/dnsconfig.h
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.Fd #define DNSCONFIG_MAX_SERVERS 3
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.Ft int
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.Fn getdnsconfig "struct dnsconfig *cfg"
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.Ft int
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.Fn getdnsconfig "const struct dnsconfig *cfg"
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.Sh DESCRIPTION
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.Fn getdnsconfig
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gets and
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.Fn setdnsconfig
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sets the kernel DNS resolver list.
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.Pp
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.Fa cfg
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points to a
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.Vt struct dnsconfig
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structure.
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The
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.Fa servers
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array can contain up to
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.Dv DNSCONFIG_MAX_SERVERS
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DNS resolvers.
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The
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.Fa servers_count
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field marks how many of the entries in
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.Fa servers
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are populated.
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.Bd -literal
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struct dnsconfig {
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size_t servers_count;
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struct dnsconfig_server servers[DNSCONFIG_MAX_SERVERS];
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}
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.Ed
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.Pp
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Each DNS resolver in the
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.Fa servers
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array is described by a
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.Vt struct dnsconfig_server
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structure.
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The resolver can be defined by either an IPv4 or an IPv6 address.
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.Pp
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For an IPv4 address
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.Fa family
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is
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.Dv AF_INET ,
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.Fa addrsize
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is
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.Fn sizeof "struct in_addr" ,
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and the address is stored in the
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.Fa in
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field of the
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.Fa addr
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union.
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.Pp
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For an IPv6 address
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.Fa family
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is
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.Dv AF_INET6 ,
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.Fa addrsize
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is
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.Fn sizeof "struct in_addr6" ,
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and the address is stored in the
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.Fa in6
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field of the
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.Fa addr
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union.
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.Bd -literal
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union dnsconfig_server_union {
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struct in_addr in;
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struct in6_addr in6;
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}
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struct dnsconfig_server {
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sa_family_t family;
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size_t addrsize;
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union dnsconfig_server_union addr;
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}
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.Ed
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.Sh RETURN VALUES
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On success 0 is returned.
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On error -1 is returned, and
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.Va errno
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is set appropriately.
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.Sh ERRORS
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.Fn getdnsconfig
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and
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.Fn setdnsconfig
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will fail if:
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.Bl -tag -width "12345678"
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.It Er EFAULT
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.Fa cfg
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points to an invalid address.
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.El
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.Pp
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.Fn setdnsconfig
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will additionally fail if:
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.Bl -tag -width "12345678"
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.It Er EAFNOSUPPORT
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.Fa family
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is set to an address family other than
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.Dv AF_INET
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or
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.Dv AF_INET6 .
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.It Er EINVAL
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.Fa servers_count
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is larger than
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.Dv DNSCONFIG_MAX_SERVERS .
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.It Er EINVAL
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.Fa addrsize
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does not match the size of the address corresponding to
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.Fa family .
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.El
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.Sh SEE ALSO
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.Xr inet 4 ,
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.Xr inet6 4 ,
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.Xr dhclient 8 ,
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.Xr dnsconfig 8
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.Sh HISTORY
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The
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.Fn getdnsconfig
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and
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.Fn setdnsconfig
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system calls originally appeared in Sortix 1.1.
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