swrap: Simplify cmspace calculation in swrap_sendmsg_copy_cmsg()

swrap: Simplify cmspace calculation in swrap_sendmsg_copy_cmsg()

With cmsg->cmsg_len = CMSG_LEN(len) =>

CMSG_ALIGN(cmsg->cmsg_len) =

CMSG_ALIGN(CMSG_LEN(len)) =

CMSG_ALIGN(CMSG_ALIGN(sizeof(struct cmsghdr)) + len) =

CMSG_ALIGN(sizeof(struct cmsghdr)) + CMSG_ALIGN(len) =

CMSG_SPACE(len) =

CMSG_SPACE(CMSG_ALIGN(sizeof(struct cmsghdr)) + len - CMSG_ALIGN(sizeof(struct cmsghdr))) =

CMSG_SPACE(CMSG_LEN(len) - CMSG_ALIGN(sizeof(struct cmsghdr))) =

CMSG_SPACE(cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr)))

:)

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>