On Tue, 9 Jul 2002, Juan Francisco Rodriguez Hervella wrote: > Hello: > > I'm seeing that "struct sockaddr_in" has a field like this: > > char sin_zero[8]; > > Why ? > Could anyone explain me what's used for ? > > Could it be bad if I'd add the same field to > "sockaddr_in6" ? > > PS: I'm trying to implement divert sockets for > IPv6 using the KAME implementation of "ip6fw". > > Thanks. > > JFRH. >
The minimum size of a sockaddr's address portion (as defined in sys/socket.h) is 14 bytes (max is SOCK_MAXADDRLEN = 255); combined with the size of the sa_len and sa_family fields you get a minimum length of 16 bytes for the entire structure. The sin_zero field of sockaddr_in is to pad the structure out to this minimum length. Given that a sockaddr_in6 is already larger than the minimum required, there really isn't any point in adding the padding field to it. Kelly -- Kelly Yancey -- kbyanc@{posi.net,FreeBSD.org} To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-net" in the body of the message