taglinefilesource code
last_xmit525drivers/net/ppp.cppp->last_xmit  = jiffies - flag_time;
last_xmit1976drivers/net/ppp.cif (jiffies - ppp->last_xmit > flag_time)
last_xmit1979drivers/net/ppp.cppp->last_xmit = jiffies;
last_xmit127include/linux/if_pppvar.h__u32      last_xmit;  /* time of last transmission  */