X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=7f8d596d7d648511aa6478db75bc706159874be0;hp=5d7c3fef7d15a5c2c58d380f5f0412bb493deb4a;hb=eb578d92fd87aeb86c0832689000dc772e689f92;hpb=35bbbf736c75f13c2bf9f6d6bdc2feecd42072cb

diff --git a/net.c b/net.c
index 5d7c3fef..7f8d596d 100644
--- a/net.c
+++ b/net.c
@@ -322,6 +322,28 @@ char *remote_name(int sockfd)
 	return __get_sock_name(sockfd, getpeername);
 }
 
+/**
+ * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
+ * \param ss Container of IPv4/6 address
+ * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
+ *
+ * \sa RFC 3493
+ */
+struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
+{
+	struct in_addr ia = { 0 };
+
+	if (ss->ss_family == AF_INET)
+		 ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
+	if (ss->ss_family == AF_INET6) {
+		const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
+
+		if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
+			memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
+	}
+	return ia;
+}
+
 /*
  * Send out a buffer, resend on short writes.
  *