Initial commit

meta-google/recipes-google/ncsi/files/gbmc-ncsi-ip-from-ra.sh.in

@@ -0,0 +1,95 @@
+#!/bin/bash
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+[ ! -e /usr/share/gbmc-br-lib.sh ] && exit
+
+# shellcheck source=meta-google/recipes-google/networking/network-sh/lib.sh
+source /usr/share/network/lib.sh || exit
+# shellcheck source=meta-google/recipes-google/networking/gbmc-bridge/gbmc-br-lib.sh
+source /usr/share/gbmc-br-lib.sh || exit
+
+NCSI_IF='@NCSI_IF@'
+
+old_pfx=
+old_fqdn=
+old_rtr=
+
+set_host() {
+  [[ -n "$host" && -n "$domain" && -n "$hextet" ]] || return
+
+  local fqdn="$host-n$hextet.$domain"
+  [ "$fqdn" != "$old_fqdn" ] || return
+  old_fqdn="$fqdn"
+
+  echo "Found hostname $fqdn" >&2
+  hostnamectl set-hostname "$fqdn" || true
+}
+
+set_net() {
+  [[ -n "$pfx" && -n "$rtr" ]] || return
+  [[ "$pfx" != "$old_pfx" || "$rtr" != "$old_rtr" ]] || return
+  old_pfx="$pfx"
+  old_rtr="$rtr"
+
+  echo "Found prefix $pfx from $rtr" >&2
+
+  # We no longer need NCSId if we are in this configuration
+  systemctl stop --no-block ncsid@"$NCSI_IF" || true
+
+  # Save the IP address for the interface
+  gbmc_br_set_ip "$pfx" || true
+
+  # DHCP Relay workaround until alternate source port is supported
+  # TODO: Remove this once internal relaying cleanups land
+  gbmc-ncsi-smartnic-wa.sh || true
+}
+
+w=60
+while true; do
+  start=$SECONDS
+  while read -r line; do
+    if [ -z "$line" ]; then
+      hextet=
+      pfx=
+      host=
+      domain=
+    elif [[ "$line" =~ ^Prefix' '*:' '*(.*)/([0-9]+)$ ]]; then
+      t_pfx="${BASH_REMATCH[1]}"
+      t_pfx_len="${BASH_REMATCH[2]}"
+      ip_to_bytes t_pfx_b "$t_pfx" || continue
+      (( t_pfx_len == 76 && t_pfx_b[8] & 0xfd == 0xfd )) || continue
+      (( t_pfx_b[9] |= 1 ))
+      hextet="fd$(printf '%02x' "${t_pfx_b[9]}")"
+      pfx="$(ip_bytes_to_str t_pfx_b)"
+    elif [[ "$line" =~ ^'DNS search list'' '*:' '*([^.]+)(.*[.]google[.]com)$ ]]; then
+      # Ideally, we use PCRE and with lookahead and can do this in a single regex
+      #   ^([a-zA-Z0-9-]+(?=-n[a-fA-F0-9]{1,4})|[a-zA-Z0-9-]+(?!-n[a-fA-F0-9]{1,4}))[^.]*[.]((?:[a-zA-Z0-9]*[.])*google[.]com)$
+      # Instead we do multiple steps to extract the needed info
+      host="${BASH_REMATCH[1]}"
+      domain="${BASH_REMATCH[2]#.}"
+      if [[ "$host" =~ (-n[a-fA-F0-9]{1,4})$ ]]; then
+        host="${host%"${BASH_REMATCH[1]}"}"
+      fi
+    elif [[ "$line" =~ ^from' '(.*)$ ]]; then
+      rtr="${BASH_REMATCH[1]}"
+      set_net || true
+      set_host || true
+    fi
+  done < <(rdisc6 -d -m "$NCSI_IF" -w $(( w * 1000 )) 2>/dev/null)
+  # If rdisc6 exits early we still want to wait the full `w` time before
+  # starting again.
+  (( timeout = start + w - SECONDS ))
+  sleep $(( timeout < 0 ? 0 : timeout ))
+done