The MSG_TRUNC flag is set in the msghdr when a message is truncated.
Fixesgoogle/gvisor#200
PiperOrigin-RevId: 244440486
Change-Id: I03c7d5e7f5935c0c6b8d69b012db1780ac5b8456
netlink_autobind() sets a port id to a process ID, if this address is
available. Otherwise, it will set a port id to a random negative value.
PiperOrigin-RevId: 230631956
Change-Id: I11692e4fe9421e77d9406627b4e7772e4d9b105a