HelenOS sources

NIC_SET_PAUSE     546 uspace/lib/drv/generic/remote_nic.c 	    NIC_SET_PAUSE, allow_send, allow_receive, pause);
NIC_SET_PAUSE    2508 uspace/lib/drv/generic/remote_nic.c 	[NIC_SET_PAUSE] = remote_nic_set_pause,
HelenOS homepage, sources at GitHub