bgpd: deny redefinition of default RIBs

[Denis Fondras]

Redefining a default RIB is not desirable.

Index: bgpd.h
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/bgpd.h,v
retrieving revision 1.352
diff -u -p -r1.352 bgpd.h
--- bgpd.h      4 Nov 2018 14:34:00 -0000       1.352
+++ bgpd.h      4 Nov 2018 17:49:38 -0000
@@ -1057,6 +1057,7 @@ extern struct rib_names ribnames;
 #define F_RIB_NOEVALUATE       0x0002
 #define F_RIB_NOFIB            0x0004
 #define F_RIB_NOFIBSYNC                0x0008
+#define F_RIB_DEFAULT          0x0010
 #define F_RIB_HASNOFIB         (F_RIB_NOFIB | F_RIB_NOEVALUATE)
 
 /* 4-byte magic AS number */
Index: parse.y
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/parse.y,v
retrieving revision 1.362
diff -u -p -r1.362 parse.y
--- parse.y     1 Nov 2018 00:18:44 -0000       1.362
+++ parse.y     4 Nov 2018 17:49:38 -0000
@@ -3319,10 +3319,10 @@ parse_config(char *filename, struct bgpd
        netconf = &conf->networks;
 
        add_rib("Adj-RIB-In", conf->default_tableid,
-           F_RIB_NOFIB | F_RIB_NOEVALUATE);
+           F_RIB_NOFIB | F_RIB_NOEVALUATE | F_RIB_DEFAULT);
        add_rib("Adj-RIB-Out", conf->default_tableid,
-           F_RIB_NOFIB | F_RIB_NOEVALUATE);
-       add_rib("Loc-RIB", conf->default_tableid, F_RIB_LOCAL);
+           F_RIB_NOFIB | F_RIB_NOEVALUATE | F_RIB_DEFAULT);
+       add_rib("Loc-RIB", conf->default_tableid, F_RIB_LOCAL | F_RIB_DEFAULT);
 
        if ((file = pushfile(filename, 1)) == NULL) {
                free(conf);
@@ -3876,6 +3876,11 @@ add_rib(char *name, u_int rtableid, u_in
                        return (-1);
                }
        }
+       if (rr->flags & F_RIB_DEFAULT) {
+               yyerror("redefinition of %s not permitted", rr->name);
+               return (-1);
+       }
+
        if (strlcpy(rr->name, name, sizeof(rr->name)) >= sizeof(rr->name)) {
                yyerror("rib name \"%s\" too long: max %zu",
                   name, sizeof(rr->name) - 1);
Index: rde.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/rde.c,v
retrieving revision 1.445
diff -u -p -r1.445 rde.c
--- rde.c       4 Nov 2018 12:34:54 -0000       1.445
+++ rde.c       4 Nov 2018 17:49:38 -0000
@@ -217,8 +217,10 @@ rde_main(int debug, int verbose)
        peer_init(peerhashsize);
 
        /* make sure the default RIBs are setup */
-       rib_new("Adj-RIB-In", 0, F_RIB_NOFIB | F_RIB_NOEVALUATE);
-       rib_new("Adj-RIB-Out", 0, F_RIB_NOFIB | F_RIB_NOEVALUATE);
+       rib_new("Adj-RIB-In", 0, F_RIB_NOFIB | F_RIB_NOEVALUATE |
+           F_RIB_DEFAULT);
+       rib_new("Adj-RIB-Out", 0, F_RIB_NOFIB | F_RIB_NOEVALUATE |
+           F_RIB_DEFAULT);
 
        out_rules = calloc(1, sizeof(struct filter_head));
        if (out_rules == NULL)