utils: rework u_parse_ip4addr()

Redefine u_parse_ip4addr() to match the behaviour of other u_parse_*()
functions:

  * Drop the err_msg parameter.
  * Return the number of bytes parsed instead of an error number.
  * Remove support for fancy IPv4 address notations.

There is currently only one user of u_parse_ip4addr() (in iprange.c).
Dropping the fancy IPv4 address representations is probably not going
to harm anyone (quite the opposite as many users don't realise that
leading 0 means octal and that plain integers can be considered IPv4
addresses).
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>

accel-pppd/iprange.c

@@ -51,7 +51,6 @@ static int parse_iprange(const char *str, struct iprange_t **range)
 	char ipstr[CIDR_MAXLEN + 1] = { 0 };
 	struct iprange_t *_range;
 	struct in_addr addr;
-	const char *errmsg;
 	char *suffix_str;
 	uint32_t ipmin;
 	uint32_t ipmax;
@@ -88,7 +87,7 @@ static int parse_iprange(const char *str, struct iprange_t **range)
 	*suffix_str = '\0';
 	++suffix_str;
 
-	if (u_parse_ip4addr(ipstr, &addr, &errmsg)) {
+	if (!u_parse_ip4addr(ipstr, &addr)) {
 		log_error("iprange: impossible to parse range \"%s\":"
 			  " invalid IPv4 address \"%s\"\n",
 			  str, ipstr);

accel-pppd/utils.c

 #include <arpa/inet.h>
 #include <ctype.h>
 #include <errno.h>
-#include <netdb.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -167,31 +166,6 @@ size_t __export u_parse_u32(const char *str, uint32_t *val)
 	return endptr - str;
 }
 
-int __export u_parse_ip4addr(const char *src, struct in_addr *addr,
-			     const char **err_msg)
-{
-	struct addrinfo hint = {
-		.ai_flags = AI_NUMERICHOST,
-		.ai_family = AF_INET,
-		.ai_socktype = 0,
-		.ai_protocol = 0,
-	};
-	struct addrinfo *ainfo;
-	int err;
-
-	err = getaddrinfo(src, NULL, &hint, &ainfo);
-	if (err) {
-		*err_msg = gai_strerror(err);
-		return err;
-	}
-
-	*addr = ((struct sockaddr_in *)ainfo->ai_addr)->sin_addr;
-
-	freeaddrinfo(ainfo);
-
-	return 0;
-}
-
 /* Parse an IPv6 address (for example "2001:db8::1").
  * Returns the number of bytes parsed, or 0 if str doesn't start with an IPv6
  * address.
@@ -214,6 +188,31 @@ size_t __export u_parse_ip6addr(const char *str, struct in6_addr *addr)
 	return len;
 }
 
+/* Parse an IPv4 address in dotted-decimal format (for example "198.51.100.1").
+ * Other formats (hex "0xc6.0x33.0x64.0x1", octal "0306.063.0144.01", mixed
+ * "0xc6.51.0144.1", non dotted-quad "198.51.25601"...) are rejected.
+ *
+ * Returns the number of bytes parsed, or 0 if str doesn't start with an IPv4
+ * address.
+ */
+size_t __export u_parse_ip4addr(const char *str, struct in_addr *addr)
+{
+	char buf[INET_ADDRSTRLEN];
+	size_t len;
+
+	len = strspn(str, ".0123456789");
+	if (!len || len >= sizeof(buf))
+		return 0;
+
+	memcpy(buf, str, len);
+	buf[len] = '\0';
+
+	if (inet_pton(AF_INET, buf, addr) != 1)
+		return 0;
+
+	return len;
+}
+
 /* Parse an IPv6 network prefix in CIDR notation (for example "2001:db8::/32").
  * Returns the number of bytes parsed, or 0 if str doesn't start with an IPv6
  * network prefix.

accel-pppd/utils.h

@@ -16,9 +16,9 @@ size_t u_parse_u8(const char *str, uint8_t *val);
 size_t u_parse_u16(const char *str, uint16_t *val);
 size_t u_parse_u32(const char *str, uint32_t *val);
 
-int u_parse_ip4addr(const char *src, struct in_addr *addr,
-		    const char **err_msg);
 size_t u_parse_ip6addr(const char *str, struct in6_addr *addr);
+size_t u_parse_ip4addr(const char *str, struct in_addr *addr);
+
 size_t u_parse_ip6cidr(const char *str, struct in6_addr *netp, uint8_t *plen);
 
 int u_randbuf(void *buf, size_t buf_len, int *err);