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Tobias Waldekranz 4e83520b0e ixll: Fix ping(8)s that require all options precede address
The default ping(8) shipped with alpine does not support `ping <addr>
-c1`, but happily executes `ping -c1 <addr>`. Therefore, make sure
that the address is always the last argument.
2025-01-17 14:33:41 +01:00

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# Utility functions for communicating with IPv6 neighbors on the local
# LAN
# Usage: llping <iface>
#
# Send ping to all-hosts group, with link-local scope, on <iface>,
# suppressing loopbacked packets.
llping()
{
local iface="$1"
shift
ping -L "$@" ff02::1%$iface
}
# Usage: llpeer <iface>
#
# Return the address of the first IPv6 neighbor to respond on
# <iface>'s local LAN. It is thus typically only useful in scenarios
# where only one neighbor exists
llpeer()
{
local iface="$1"
shift
llping $iface -c1 "$@" | \
awk '/bytes from/ { sub(/:$/, "", $4); print($4); exit(0); }'
}
llssh_expand()
{
local old_ifs="$IFS"
local orig="$1"
local fmt="$2"
local peer=
local user=
local iface=
IFS=@
set $1
IFS="$old_ifs"
case $# in
1)
user="$LLSSH_USER"
iface="$1"
;;
2)
user="$1"
iface="$2"
;;
*)
echo "Error: Invalid peer \"$orig1\"" >&2
return 1
;;
esac
if [ -d "/sys/class/net/$iface" ]; then
peer="$(llpeer $iface -w3)"
else
peer="$iface"
fi
if [ ! "$peer" ]; then
echo "Error: No peer responded on $iface" >&2
return 1
fi
case "$fmt" in
ssh)
;;
scp)
peer="[$peer]"
;;
*)
echo "Internal error: Invalid format \"$fmt\"" >&2
return 1
;;
esac
[ "$user" ] && peer="$user@$peer"
echo $peer
}
# Usage: llssh <destination> [<ssh-args>]
#
# ssh(1) to <destination>, but if the host matches an existing
# interface name, expand it to a neighboring host on that interface.
llssh()
{
local remote="$1"
shift
local peer="$(llssh_expand $remote ssh)"
[ "$peer" ] || return 1
local sshpasscmd=
[ "$LLSSH_PASS" ] && sshpasscmd="sshpass -p$LLSSH_PASS $LLSSHPASS_OPTS"
$sshpasscmd ssh $LLSSH_OPTS $peer "$@"
}
llscp_expand()
{
local orig="$1"
local old_ifs="$IFS"
local peer=
IFS=:
set $@
IFS="$old_ifs"
case $# in
1)
echo "$1"
;;
2)
peer="$(llssh_expand $1 scp)"
[ "$peer" ] || return 1
echo "$peer:$2"
;;
*)
echo "Error: Invalid location \"$orig1\"" >&2
return 1
;;
esac
}
# Usage: llscp <src> <dst>
#
# scp(1) from <src> to <dst>, but expand any host specified in either
# <src> or <dst>, which matches an existing interface name, to a
# neighboring host on that interface.
llscp()
{
local src="$(llscp_expand $1)"
local dst="$(llscp_expand $2)"
[ "$src" -a "$dst" ] || return 1
shift 2
local sshpasscmd=
[ "$LLSSH_PASS" ] && sshpasscmd="sshpass -p$LLSSH_PASS $LLSSHPASS_OPTS"
$sshpasscmd scp $LLSCP_OPTS "$src" "$dst"
}