fix: make keygen autodetect source ip

scripts/keygen.sh

@@ -5,7 +5,6 @@ KEY_DIR="${MAIL_LOGIN_KEY_DIR:-/usr/local/hitme_plugins/mail-login/secrets}"
 KEY_NAME="${MAIL_LOGIN_KEY_NAME:-mx1_ed25519}"
 KEY_PATH="$KEY_DIR/$KEY_NAME"
 MX_MODE="${MX_LOGIN_MODE:-1}"
-SOURCE_IP="${SOURCE_IP:-SOURCE_SERVER_PUBLIC_IP}"
 HELPER_COMMAND="${MAIL_LOGIN_HELPER_COMMAND:-/usr/local/hitme_plugins/mail-login-helper/bin/create-login-url}"
 
 derive_servername() {
@@ -21,6 +20,31 @@ clean_label() {
   printf '%s' "$1" | tr '[:upper:]' '[:lower:]' | sed 's/[^a-z0-9-]/-/g; s/^-*//; s/-*$//'
 }
 
+detect_source_ip() {
+  if [ -n "${SOURCE_IP:-}" ]; then
+    printf '%s' "$SOURCE_IP"
+    return
+  fi
+
+  if command -v ip >/dev/null 2>&1; then
+    detected="$(ip route get 1.1.1.1 2>/dev/null | awk '{for (i=1;i<=NF;i++) if ($i=="src") {print $(i+1); exit}}')"
+    if [ -n "$detected" ]; then
+      printf '%s' "$detected"
+      return
+    fi
+  fi
+
+  if command -v hostname >/dev/null 2>&1; then
+    detected="$(hostname -I 2>/dev/null | awk '{print $1}')"
+    if [ -n "$detected" ]; then
+      printf '%s' "$detected"
+      return
+    fi
+  fi
+
+  return 1
+}
+
 SERVER_LABEL="$(clean_label "$(derive_servername)")"
 if [ -z "$SERVER_LABEL" ]; then
   echo "Cannot determine SERVERNAME" >&2
@@ -35,9 +59,10 @@ case "$MX_MODE" in
     ;;
 esac
 
+SOURCE_IP="$(detect_source_ip || true)"
 case "$SOURCE_IP" in
   *[!A-Za-z0-9:./_-]*|'')
-    echo "SOURCE_IP contains unsupported characters" >&2
+    echo "Cannot determine SOURCE_IP automatically. Set SOURCE_IP explicitly." >&2
     exit 1
     ;;
 esac
@@ -82,4 +107,3 @@ MAIL_LOGIN_SSH_KNOWN_HOSTS=/root/.ssh/known_hosts
 Add this line to /root/.ssh/authorized_keys on mx1:
 $AUTH_OPTIONS $PUB_KEY $COMMENT
 EOF
-