+/*
+ * Convert a bit token value to a string; use "fmt" if not found.
+ * this is useful for parsing bitfields, the output strings are comma seperated
+ */
+char *
+bittok2str(register const struct tok *lp, register const char *fmt,
+ register int v)
+{
+ static char buf[256]; /* our stringbuffer */
+ int buflen=0;
+ register int rotbit; /* this is the bit we rotate through all bitpositions */
+ register int tokval;
+
+ while (lp->s != NULL) {
+ tokval=lp->v; /* load our first value */
+ rotbit=1;
+ while (rotbit != 0) {
+ /*
+ * lets AND the rotating bit with our token value
+ * and see if we have got a match
+ */
+ if (tokval == (v&rotbit)) {
+ /* ok we have found something */
+ buflen+=snprintf(buf+buflen, sizeof(buf)-buflen, "%s, ",lp->s);
+ break;
+ }
+ rotbit=rotbit<<1; /* no match - lets shift and try again */
+ }
+ lp++;
+ }
+
+ if (buflen != 0) { /* did we find anything */
+ /* yep, set the the trailing zero 2 bytes before to eliminate the last comma & whitespace */
+ buf[buflen-2] = '\0';
+ return (buf);
+ }
+ else {
+ /* bummer - lets print the "unknown" message as advised in the fmt string if we got one */
+ if (fmt == NULL)
+ fmt = "#%d";
+ (void)snprintf(buf, sizeof(buf), fmt, v);
+ return (buf);
+ }
+}
+
+/*
+ * Convert a value to a string using an array; the macro
+ * tok2strary() in <interface.h> is the public interface to
+ * this function and ensures that the second argument is
+ * correct for bounds-checking.
+ */
+const char *
+tok2strary_internal(register const char **lp, int n, register const char *fmt,
+ register int v)
+{
+ static char buf[128];
+
+ if (v >= 0 && v < n && lp[v] != NULL)
+ return lp[v];
+ if (fmt == NULL)
+ fmt = "#%d";
+ (void)snprintf(buf, sizeof(buf), fmt, v);
+ return (buf);
+}
+
+/*
+ * Convert a 32-bit netmask to prefixlen if possible
+ * the function returns the prefix-len; if plen == -1
+ * then conversion was not possible;
+ */
+
+int
+mask2plen (u_int32_t mask)
+{
+ u_int32_t bitmasks[33] = {
+ 0x00000000,
+ 0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
+ 0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
+ 0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
+ 0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
+ 0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
+ 0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
+ 0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
+ 0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff
+ };
+ int prefix_len = 32;
+
+ /* let's see if we can transform the mask into a prefixlen */
+ while (prefix_len >= 0) {
+ if (bitmasks[prefix_len] == mask)
+ break;
+ prefix_len--;
+ }
+ return (prefix_len);
+}