对ip_frag_reasm我的理解

/* This data is invariant across clones and lives at
* the end of the header data, ie. at skb->end.
*/
struct skb_shared_info {
atomic_t dataref;
#ifdef CONFIG_MIPS_BRCM
/* to preserve compat with binary only modules, do not change the
* position of this field relative to the start of the structure. */
__u8 *dirty_p;