From: David S. Miller Date: Tue, 14 Feb 2017 17:13:52 +0000 (-0500) Subject: Merge branch 'ipv6-v4mapped' X-Git-Tag: v4.10~23^2~14 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=144adc655fac089d485ee66354d402b319cff6d2;p=karo-tx-linux.git Merge branch 'ipv6-v4mapped' Jonathan T. Leighton says: ==================== IPv4-mapped on wire, :: dst address issue Under some circumstances IPv6 datagrams are sent with IPv4-mapped IPv6 addresses as the source. Given an IPv6 socket bound to an IPv4-mapped IPv6 address, and an IPv6 destination address, both TCP and UDP will will send packets using the IPv4-mapped IPv6 address as the source. Per RFC 6890 (Table 20), IPv4-mapped IPv6 source addresses are not allowed in an IP datagram. The problem can be observed by attempting to connect() either a TCP or UDP socket, or by using sendmsg() with a UDP socket. The patch is intended to correct this issue for all socket types. linux follows the BSD convention that an IPv6 destination address specified as in6addr_any is converted to the loopback address. Currently, neither TCP nor UDP consider the possibility that the source address is an IPv4-mapped IPv6 address, and assume that the appropriate loopback address is ::1. The patch adds a check on whether or not the source address is an IPv4-mapped IPv6 address and then sets the destination address to either ::ffff:127.0.0.1 or ::1, as appropriate. ==================== Signed-off-by: David S. Miller --- 144adc655fac089d485ee66354d402b319cff6d2