- fix ip route rejecting dotted quads as prefix

- adjust error message for wrong prefix not to mention address
  Previously e.g. ip route add 127.0.0.0/255.0.0.0 dev dummy0
  was rejected, saying
ip: an inet address is expected rather than "127.0.0.0/255.0.0.0"
 
function                                             old     new   delta
get_prefix_1                                         201     309    +108
get_prefix                                            55      73     +18
get_addr                                              55      73     +18
get_addr32                                            48      58     +10
get_addr_1                                           249     204     -45
.rodata                                           114569  114524     -45
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/2 up/down: 154/-90)            Total: 64 bytes

networking/libiproute/utils.c

@@ -115,10 +115,6 @@ int get_s8(int8_t * val, char *arg, int base)
 
 int get_addr_1(inet_prefix * addr, char *name, int family)
 {
-	char *cp;
-	unsigned char *ap = (unsigned char *) addr->data;
-	int i;
-
 	memset(addr, 0, sizeof(*addr));
 
 	if (strcmp(name, bb_str_default) == 0 ||
@@ -143,24 +139,17 @@ int get_addr_1(inet_prefix * addr, char *name, int family)
 	addr->family = AF_INET;
 	if (family != AF_UNSPEC && family != AF_INET)
 		return -1;
+	if (inet_pton(AF_INET, name, addr->data) <= 0)
+		return -1;
 	addr->bytelen = 4;
 	addr->bitlen = -1;
-	for (cp = name, i = 0; *cp; cp++) {
-		if (*cp <= '9' && *cp >= '0') {
-			ap[i] = 10 * ap[i] + (*cp - '0');
-			continue;
-		}
-		if (*cp == '.' && ++i <= 3)
-			continue;
-		return -1;
-	}
 	return 0;
 }
 
 int get_prefix_1(inet_prefix * dst, char *arg, int family)
 {
 	int err;
-	int plen;
+	unsigned plen;
 	char *slash;
 
 	memset(dst, 0, sizeof(*dst));
@@ -177,23 +166,36 @@ int get_prefix_1(inet_prefix * dst, char *arg, int family)
 		*slash = '\0';
 	err = get_addr_1(dst, arg, family);
 	if (err == 0) {
-		switch (dst->family) {
+		dst->bitlen = (dst->family == AF_INET6) ? 128 : 32;
-		case AF_INET6:
-			dst->bitlen = 128;
-			break;
-		default:
-		case AF_INET:
-			dst->bitlen = 32;
-		}
 		if (slash) {
-			if (get_integer(&plen, slash + 1, 0) || plen > dst->bitlen) {
+			inet_prefix netmask_pfx;
+
+			netmask_pfx.family = AF_UNSPEC;
+			if ((get_unsigned(&plen, slash + 1, 0) || plen > dst->bitlen)
+				&& (get_addr_1(&netmask_pfx, slash + 1, family)))
 				err = -1;
-				goto done;
+			else 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 >= 0 && plen <= dst->bitlen) {
+							dst->bitlen = plen;
+							/* dst->flags |= PREFIXLEN_SPECIFIED; */
+					} else
+						err = -1;
+				} else
+					err = -1;
+			} else {
+				/* plain prefix */
 				dst->bitlen = plen;
 			}
 		}
- done:
+	}
 	if (slash)
 		*slash = '/';
 	return err;
@@ -202,10 +204,10 @@ int get_prefix_1(inet_prefix * dst, char *arg, int family)
 int get_addr(inet_prefix * dst, char *arg, int family)
 {
 	if (family == AF_PACKET) {
-		bb_error_msg_and_die("\"%s\" may be inet address, but it is not allowed in this context", arg);
+		bb_error_msg_and_die("\"%s\" may be inet %s, but it is not allowed in this context", arg, "address");
 	}
 	if (get_addr_1(dst, arg, family)) {
-		bb_error_msg_and_die("an inet address is expected rather than \"%s\"", arg);
+		bb_error_msg_and_die("an %s %s is expected rather than \"%s\"", "inet", "address", arg);
 	}
 	return 0;
 }
@@ -213,10 +215,10 @@ int get_addr(inet_prefix * dst, char *arg, int family)
 int get_prefix(inet_prefix * dst, char *arg, int family)
 {
 	if (family == AF_PACKET) {
-		bb_error_msg_and_die("\"%s\" may be inet address, but it is not allowed in this context", arg);
+		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 inet address is expected rather than \"%s\"", arg);
+		bb_error_msg_and_die("an %s %s is expected rather than \"%s\"", "inet", "prefix", arg);
 	}
 	return 0;
 }
@@ -226,7 +228,7 @@ uint32_t get_addr32(char *name)
 	inet_prefix addr;
 
 	if (get_addr_1(&addr, name, AF_INET)) {
-		bb_error_msg_and_die("an IP address is expected rather than \"%s\"", name);
+		bb_error_msg_and_die("an %s %s is expected rather than \"%s\"", "IP", "address", name);
 	}
 	return addr.data[0];
 }

networking/libiproute/utils.h

@@ -39,6 +39,8 @@ typedef struct {
 	uint32_t data[4];
 } inet_prefix;
 
+#define PREFIXLEN_SPECIFIED 1
+
 #define DN_MAXADDL 20
 #ifndef AF_DECnet
 #define AF_DECnet 12