Hi There, In "tcp_v4_rcv()", "tcp_v4_checksum_init()" is called if skb->ip_summed != CHECKSUM_UNNECESSARY. In "tcp_v4_checksum_init()", "tcp_v4_check()" is called if skb->ip_summed == CHECKSUM_HW. To my understanding, the TCP checksum should be verified if ip_summed == CHECKSUM_HW, how come it is verified again here? Is skb->csum useful for the receiving path? Thanks, Bluesea __________________________________ Do you Yahoo!? The New Yahoo! Shopping - with improved product search http://shopping.yahoo.com - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html