link-local IPv6 addresses need a '%interface' specification to be useful

This commit is contained in:
Joshua Tauberer 2014-08-31 08:09:13 -04:00
parent 24ff0e04b1
commit cfffb38508

View file

@ -85,6 +85,9 @@ function get_default_privateip {
# Return the IP address of the network interface connected
# to the Internet.
#
# Pass '4' or '6' as an argument to this function to specify
# what type of address to get (IPv4, IPv6).
#
# We used to use `hostname -I` and then filter for either
# IPv4 or IPv6 addresses. However if there are multiple
# network interfaces on the machine, not all may be for
@ -99,11 +102,16 @@ function get_default_privateip {
# assigned to an interface. `ip route get` reports the
# preferred. That's good enough for us. See issue #121.
#
# With IPv6, the best route may be via an interface that
# only has a link-local address (fe80::*). These addresses
# are only unique to an interface and so need an explicit
# interface specification in order to use them with bind().
# In these cases, we append "%interface" to the address.
# See the Notes section in the man page for getaddrinfo and
# https://discourse.mailinabox.email/t/update-broke-mailinabox/34/9.
#
# Also see ae67409603c49b7fa73c227449264ddd10aae6a9 and
# issue #3 for why/how we originally added IPv6.
#
# Pass '4' or '6' as an argument to this function to specify
# what type of address to get (IPv4, IPv6).
target=8.8.8.8
@ -112,9 +120,21 @@ function get_default_privateip {
# as it's an address on the public Internet.
if [ "$1" == "6" ]; then target=2001:4860:4860::8888; fi
ip -$1 -o route get $target \
| grep -v unreachable \
| sed "s/.* src \([^ ]*\).*/\1/"
# Get the route information.
route=$(ip -$1 -o route get $target | grep -v unreachable)
# Parse the address out of the route information.
address=$(echo $route | sed "s/.* src \([^ ]*\).*/\1/")
if [[ "$1" == "6" && $address == fe80:* ]]; then
# For IPv6 link-local addresses, parse the interface out
# of the route information and append it with a '%'.
interface=$(echo $route | sed "s/.* dev \([^ ]*\).*/\1/")
address=$address%$interface
fi
echo $address
}
function ufw_allow {