--- usr.sbin/ngctl/dot.c        (working copy)	
+++ usr.sbin/ngctl/dot.c        (working copy)	
@@ -2,6 +2,7 @@ 
 /*
  * dot.c
  *
+ * Copyright (c) 2019 Lutz Donnerhacke
  * Copyright (c) 2004 Brian Fundakowski Feldman
  * Copyright (c) 1996-1999 Whistle Communications, Inc.
  * All rights reserved.
@@ -53,9 +54,11 @@ 
 
 const struct ngcmd dot_cmd = {
        DotCmd,
-       "dot [outputfile]",
+       "dot [-c] [outputfile]",
        "Produce a GraphViz (.dot) of the entire netgraph.",
-       "If no outputfile is specified, stdout will be assumed.",
+       "If no outputfile is specified, stdout will be assumed."
+       " The optional -c argument generates a graph without separate"
+       " structures for egde names. Such a graph is more compact.",
        { "graphviz", "confdot" }
 };
 
@@ -66,12 +69,16 @@ 
        struct namelist *nlist;
        FILE *f = stdout;
        int ch;
+       int compact = 0;
        u_int i;
 
        /* Get options */
        optind = 1;
-       while ((ch = getopt(ac, av, "")) != -1) {
+       while ((ch = getopt(ac, av, "c")) != -1) {
                switch (ch) {
+               case 'c':
+                       compact = 1;
+                       break;
                case '?':
                default:
                        return (CMDRTN_USAGE);
@@ -109,9 +116,14 @@ 
        }
 
        nlist = (struct namelist *)nlresp->data;
-       fprintf(f, "graph netgraph {\n");
-       /* TODO: implement rank = same or subgraphs at some point */
-       fprintf(f, "\tedge [ weight = 1.0 ];\n");
+       if(compact) {
+               fprintf(f, "digraph netgraph {\n");
+               fprintf(f, "\tedge [ dir = \"none\", fontsize = 10 ];\n");
+       } else {
+               fprintf(f, "graph netgraph {\n");
+               /* TODO: implement rank = same or subgraphs at some point */
+               fprintf(f, "\tedge [ weight = 1.0 ];\n");
+       }
        fprintf(f, "\tnode [ shape = record, fontsize = 12 ] {\n");
        for (i = 0; i < nlist->numnames; i++)
                fprintf(f, "\t\t\"%jx\" [ label = \"{%s:|{%s|[%jx]:}}\" ];\n",
@@ -159,30 +171,40 @@ 
                        continue;
                }
 
-               fprintf(f, "\tnode [ shape = octagon, fontsize = 10 ] {\n");
-               for (j = 0; j < ninfo->hooks; j++)
-                       fprintf(f, "\t\t\"%jx.%s\" [ label = \"%s\" ];\n",
-                           (uintmax_t)nlist->nodeinfo[i].id,
-                           hlist->link[j].ourhook, hlist->link[j].ourhook);
-               fprintf(f, "\t};\n");
+               if(!compact) {
+                       fprintf(f, "\tnode [ shape = octagon, fontsize = 10 ] {\n");
+                       for (j = 0; j < ninfo->hooks; j++)
+                         fprintf(f, "\t\t\"%jx.%s\" [ label = \"%s\" ];\n",
+                                 (uintmax_t)nlist->nodeinfo[i].id,
+                                 hlist->link[j].ourhook, hlist->link[j].ourhook);
+                       fprintf(f, "\t};\n");
+
+                       fprintf(f, "\t{\n\t\tedge [ weight = 2.0, style = bold ];\n");
+                       for (j = 0; j < ninfo->hooks; j++)
+                         fprintf(f, "\t\t\"%jx\" -- \"%jx.%s\";\n",
+                                 (uintmax_t)nlist->nodeinfo[i].id,
+                                 (uintmax_t)nlist->nodeinfo[i].id,
+                                 hlist->link[j].ourhook);
+                       fprintf(f, "\t};\n");
+               }
 
-               fprintf(f, "\t{\n\t\tedge [ weight = 2.0, style = bold ];\n");
-               for (j = 0; j < ninfo->hooks; j++)
-                       fprintf(f, "\t\t\"%jx\" -- \"%jx.%s\";\n",
-                           (uintmax_t)nlist->nodeinfo[i].id,
-                           (uintmax_t)nlist->nodeinfo[i].id,
-                           hlist->link[j].ourhook);
-               fprintf(f, "\t};\n");
-
                for (j = 0; j < ninfo->hooks; j++) {
                        /* Only print the edges going in one direction. */
                        if (hlist->link[j].nodeinfo.id > nlist->nodeinfo[i].id)
                                continue;
-                       fprintf(f, "\t\"%jx.%s\" -- \"%jx.%s\";\n",
-                           (uintmax_t)nlist->nodeinfo[i].id,
-                           hlist->link[j].ourhook,
-                           (uintmax_t)hlist->link[j].nodeinfo.id,
-                           hlist->link[j].peerhook);
+                       if(compact) {
+                               fprintf(f, "\t\"%jx\" -> \"%jx\" [ headlabel = \"%s\", taillabel =\"%s\" ] ;\n",
+                                       (uintmax_t)hlist->link[j].nodeinfo.id,
+                                       (uintmax_t)nlist->nodeinfo[i].id,
+                                       hlist->link[j].ourhook,
+                                       hlist->link[j].peerhook);
+                       } else {
+                               fprintf(f, "\t\"%jx.%s\" -- \"%jx.%s\";\n",
+                                       (uintmax_t)nlist->nodeinfo[i].id,
+                                       hlist->link[j].ourhook,
+                                       (uintmax_t)hlist->link[j].nodeinfo.id,
+                                       hlist->link[j].peerhook);
+                       }
                }
                free(hlresp);
        }