taglinefilesource code
ip_hcache_state180include/net/sock.hint        ip_hcache_state;  /* Have we a cached header    */
ip_hcache_state206net/ethernet/eth.csk->ip_hcache_state=0;  /* Try when arp resolves */
ip_hcache_state212net/ethernet/eth.csk->ip_hcache_state=1;
ip_hcache_state2390net/ipv4/ip.csk->ip_hcache_state= 0;
ip_hcache_state2400net/ipv4/ip.cif(rt->rt_dev->header_cache && sk->ip_hcache_state!= -1)
ip_hcache_state2406net/ipv4/ip.csk->ip_hcache_state= -1;
ip_hcache_state2516net/ipv4/ip.cif(sk->ip_hcache_state>0)