esis: explain why we're doing ND_TTEST_LEN(pptr, 1).

diff --git a/print-isoclns.c b/print-isoclns.c
index 3859c8ffc6af252b4f8b57968fdd26dfa6dab8fd..9e83e613aef543d5eb345203fc64de26ff6bd811 100644 (file)
--- a/print-isoclns.c
+++ b/print-isoclns.c
@@ -1382,6 +1382,10 @@ esis_print(netdissect_options *ndo,
 
        default:
                if (ndo->ndo_vflag <= 1) {
+                       /*
+                        * If there's at least one byte to print, print
+                        * it/them.
+                        */
                        if (ND_TTEST_LEN(pptr, 1))
                                print_unknown_data(ndo, pptr, "\n\t  ", ND_BYTES_AVAILABLE_AFTER(pptr));
                }