sendmsg_x accepts a destination per message on an unconnected socket; the
kernel then handles the messages one at a time internally (as sendto
would) but within a single system call. The header comment saying the
address must be zero is out of date relative to the implementation.
Updates #21486
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I3d8a1c6f2b9e4075a1d7c3e9b5f2a8d4c6e1b7f3
Brad Fitzpatrick
7b8995ff81