iproute: fix parsing and matching of of "short" IP addrs like 10/8

function                                             old     new   delta
print_route                                         1613    1813    +200
get_addr_1                                           209     258     +49
get_prefix                                           393     356     -37
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 249/-37)           Total: 212 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 54 insertions, 32 deletions

diff --git a/networking/libiproute/utils.c b/networking/libiproute/utils.c
index d32db8d..d0fe306 100644
--- a/networking/libiproute/utils.c
+++ b/networking/libiproute/utils.c
@@ -83,20 +83,43 @@ int get_addr_1(inet_prefix *addr, char *name, int family)
 		return 0;
 	}
 
-	addr->family = AF_INET;
 	if (family != AF_UNSPEC && family != AF_INET)
 		return -1;
+
+	/* Try to parse it as IPv4 */
+	addr->family = AF_INET;
+#if 0 /* Doesn't handle e.g. "10.10", for example, "ip r l root 10.10/16" */
 	if (inet_pton(AF_INET, name, addr->data) <= 0)
 		return -1;
+#else
+	{
+		unsigned i = 0;
+		unsigned n = 0;
+		const char *cp = name - 1;
+		while (*++cp) {
+			if ((unsigned char)(*cp - '0') <= 9) {
+				n = 10 * n + (unsigned char)(*cp - '0');
+				if (n >= 256)
+					return -1;
+				((uint8_t*)addr->data)[i] = n;
+				continue;
+			}
+			if (*cp == '.' && ++i <= 3) {
+				n = 0;
+				continue;
+			}
+			return -1;
+		}
+	}
+#endif
 	addr->bytelen = 4;
 	addr->bitlen = -1;
+
 	return 0;
 }
 
-static int get_prefix_1(inet_prefix *dst, char *arg, int family)
+static void get_prefix_1(inet_prefix *dst, char *arg, int family)
 {
-	int err;
-	unsigned plen;
 	char *slash;
 
 	memset(dst, 0, sizeof(*dst));
@@ -108,48 +131,50 @@ static int get_prefix_1(inet_prefix *dst, char *arg, int family)
 		dst->family = family;
 		/*dst->bytelen = 0; - done by memset */
 		/*dst->bitlen = 0;*/
-		return 0;
+		return;
 	}
 
 	slash = strchr(arg, '/');
 	if (slash)
 		*slash = '\0';
-	err = get_addr_1(dst, arg, family);
-	if (err == 0) {
+
+	if (get_addr_1(dst, arg, family) == 0) {
 		dst->bitlen = (dst->family == AF_INET6) ? 128 : 32;
 		if (slash) {
+			unsigned plen;
 			inet_prefix netmask_pfx;
 
 			netmask_pfx.family = AF_UNSPEC;
 			plen = bb_strtou(slash + 1, NULL, 0);
 			if ((errno || plen > dst->bitlen)
-			 && (get_addr_1(&netmask_pfx, slash + 1, family)))
-				err = -1;
-			else if (netmask_pfx.family == AF_INET) {
+			 && get_addr_1(&netmask_pfx, slash + 1, family) != 0
+			) {
+				goto bad;
+			}
+			if (netmask_pfx.family == AF_INET) {
 				/* fill in prefix length of dotted quad */
 				uint32_t mask = ntohl(netmask_pfx.data[0]);
 				uint32_t host = ~mask;
 
 				/* a valid netmask must be 2^n - 1 */
-				if (!(host & (host + 1))) {
-					for (plen = 0; mask; mask <<= 1)
-						++plen;
-					if (plen <= dst->bitlen) {
-						dst->bitlen = plen;
-						/* dst->flags |= PREFIXLEN_SPECIFIED; */
-					} else
-						err = -1;
-				} else
-					err = -1;
-			} else {
-				/* plain prefix */
-				dst->bitlen = plen;
+				if (host & (host + 1))
+					goto bad;
+
+				for (plen = 0; mask; mask <<= 1)
+					++plen;
+				if (plen > dst->bitlen)
+					goto bad;
+				/* dst->flags |= PREFIXLEN_SPECIFIED; */
 			}
+			dst->bitlen = plen;
 		}
 	}
+
 	if (slash)
 		*slash = '/';
-	return err;
+	return;
+ bad:
+	bb_error_msg_and_die("an %s %s is expected rather than \"%s\"", "inet", "prefix", arg);
 }
 
 int get_addr(inet_prefix *dst, char *arg, int family)
@@ -163,15 +188,12 @@ int get_addr(inet_prefix *dst, char *arg, int family)
 	return 0;
 }
 
-int get_prefix(inet_prefix *dst, char *arg, int family)
+void get_prefix(inet_prefix *dst, char *arg, int family)
 {
 	if (family == AF_PACKET) {
 		bb_error_msg_and_die("\"%s\" may be inet %s, but it is not allowed in this context", arg, "prefix");
 	}
-	if (get_prefix_1(dst, arg, family)) {
-		bb_error_msg_and_die("an %s %s is expected rather than \"%s\"", "inet", "prefix", arg);
-	}
-	return 0;
+	get_prefix_1(dst, arg, family);
 }
 
 uint32_t get_addr32(char *name)
@@ -204,10 +226,10 @@ void duparg2(const char *key, const char *arg)
 	bb_error_msg_and_die("either \"%s\" is duplicate, or \"%s\" is garbage", key, arg);
 }
 
-int inet_addr_match(inet_prefix *a, inet_prefix *b, int bits)
+int inet_addr_match(const inet_prefix *a, const inet_prefix *b, int bits)
 {
-	uint32_t *a1 = a->data;
-	uint32_t *a2 = b->data;
+	const uint32_t *a1 = a->data;
+	const uint32_t *a2 = b->data;
 	int words = bits >> 5;
 
 	bits &= 0x1f;