Pull up following revision(s) (requested by tih in ticket #639):
sys/kern/uipc_socket.c: revision 1.258
sys/kern/uipc_socket.c: revision 1.259
sys/netinet/ip_input.c: revision 1.364 (via patch)
sys/netinet/ip_output.c: revision 1.289
sys/netinet/in.h: revision 1.102
sys/netinet/in_pcb.c: revision 1.181
share/man/man9/sockopt.9: revision 1.11
sys/netinet/in_pcb.h: revision 1.65
sys/sys/socketvar.h: revision 1.146
sys/kern/uipc_syscalls.c: revision 1.189
sys/netinet/ip_output.c: revision 1.290
share/man/man4/ip.4: revision 1.41
share/man/man4/ip.4: revision 1.42
sys/kern/uipc_syscalls.c: revision 1.190

pass valsize for getsockopt like we do for setsockopt
make sure that we have enough space, don't require the exact size
(Tom Ivar Helbekkmo)

1) "#define ipi_spec_dst ipi_addr" in <netinet/in.h>
2) Change the IP_RECVPKTINFO option to control the generation of
  IP_PKTINFO control messages, the way it's done in Solaris.
3) Remove the superfluous IP_RECVPKTINFO control message.
4) Change the IP_PKTINFO option to do different things depending on
  the parameter it's supplied with:
  - If it's sizeof(int), assume it's being used as in Linux:
    - If it's non-zero, turn on the IP_RECVPKTINFO option.
    - If it's zero, turn off the IP_RECVPKTINFO option.
  - If it's sizeof(struct in_pktinfo), assume it's being used as in
    Solaris, to set a default for the source interface and/or
    source address for outgoing packets on the socket.
5) Return what Linux or Solaris compatible code expects, depending
  on data size, and just added a fallback to a Linux (and current NetBSD)
  compatible value if the size is unknown (as it is now), or,
  in the future, if the calling application specifies a receiving
  buffer that doesn't match either data item.

From: Tom Ivar Helbekkmo

new sentence-new line

Remove comment now that the getsockopt code passes the size.

Add a new sockopt member to keep track of the actual size of the option
that should be returned to the caller in getsockopt(2).
(Tom Ivar Helbekkmo)

(martin)