lib: fix prefix_cmp() return values

OMGWTFBBQ

Signed-off-by: David Lamparter <equinox@diac24.net>

diff --git a/lib/compiler.h b/lib/compiler.h
index 7c7f4ce2944d45e564f12b07b65d29e93868a432..6700ca9e8b1080b4a9b66d44eb6f08ed84998b71 100644 (file)
--- a/lib/compiler.h
+++ b/lib/compiler.h
@@ -165,6 +165,13 @@ extern "C" {
                _min_a < _min_b ? _min_a : _min_b;                             \
        })
 
+#define numcmp(a, b)                                                           \
+       ({                                                                     \
+               typeof(a) _cmp_a = (a);                                        \
+               typeof(b) _cmp_b = (b);                                        \
+               (_cmp_a < _cmp_b) ? -1 : ((_cmp_a > _cmp_b) ? 1 : 0);          \
+       })
+
 #ifndef offsetof
 #ifdef __compiler_offsetof
 #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE,MEMBER)

diff --git a/lib/prefix.c b/lib/prefix.c
index 7abeebcd0961419297ae717c62b76fcf2e31c246..1008e16a5d0093fc37865bf330b458b08c2cc8c2 100644 (file)
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -712,10 +712,11 @@ int prefix_same(const struct prefix *p1, const struct prefix *p2)
 }
 
 /*
- * Return 0 if the network prefixes represented by the struct prefix
- * arguments are the same prefix, and 1 otherwise.  Network prefixes
- * are considered the same if the prefix lengths are equal and the
- * network parts are the same.  Host bits (which are considered masked
+ * Return -1/0/1 comparing the prefixes in a way that gives a full/linear
+ * order.
+ *
+ * Network prefixes are considered the same if the prefix lengths are equal
+ * and the network parts are the same.  Host bits (which are considered masked
  * by the prefix length) are not significant.  Thus, 10.0.0.1/8 and
  * 10.0.0.2/8 are considered equivalent by this routine.  Note that
  * this routine has the same return sense as strcmp (which is different
@@ -725,44 +726,43 @@ int prefix_cmp(const struct prefix *p1, const struct prefix *p2)
 {
        int offset;
        int shift;
+       int i;
 
        /* Set both prefix's head pointer. */
        const uint8_t *pp1;
        const uint8_t *pp2;
 
        if (p1->family != p2->family)
-               return 1;
+               return numcmp(p1->family, p2->family);
        if (p1->family == AF_FLOWSPEC) {
                pp1 = (const uint8_t *)p1->u.prefix_flowspec.ptr;
                pp2 = (const uint8_t *)p2->u.prefix_flowspec.ptr;
 
                if (p1->u.prefix_flowspec.prefixlen !=
                    p2->u.prefix_flowspec.prefixlen)
-                       return 1;
+                       return numcmp(p1->u.prefix_flowspec.prefixlen,
+                                     p2->u.prefix_flowspec.prefixlen);
 
                offset = p1->u.prefix_flowspec.prefixlen;
                while (offset--)
                        if (pp1[offset] != pp2[offset])
-                               return 1;
+                               return numcmp(pp1[offset], pp2[offset]);
                return 0;
        }
        pp1 = p1->u.val;
        pp2 = p2->u.val;
 
        if (p1->prefixlen != p2->prefixlen)
-               return 1;
+               return numcmp(p1->prefixlen, p2->prefixlen);
        offset = p1->prefixlen / PNBBY;
        shift = p1->prefixlen % PNBBY;
 
-       if (shift)
-               if (maskbit[shift] & (pp1[offset] ^ pp2[offset]))
-                       return 1;
-
-       while (offset--)
-               if (pp1[offset] != pp2[offset])
-                       return 1;
+       i = memcmp(pp1, pp2, offset);
+       if (i)
+               return i;
 
-       return 0;
+       return numcmp(pp1[offset] & maskbit[shift],
+                     pp2[offset] & maskbit[shift]);
 }
 
 /*