绕过 TCP 三向握手？
Bypass TCP three way handshaking?
假设动态提供了正确的 SYN-seq 和 ack 编号，是否可以进行系统调用或编写内核模块以将 tcp 连接直接进入 ESTABLISHED 状态，而无需经过三向握手过程？
您可能想看看 TCP fast open，现代 Linux 内核实现了：
TCP Fast Open (TFO) is an extension to speed up the opening of successive Transmission Control Protocol (TCP) connections between two endpoints. It works by using a TFO cookie (a TCP option) in the initial SYN packet to authenticate a previously connected client. If successful, it may start sending data to the client before the receipt of the final ACK packet of the three way handshake is received, skipping a round trip and lowering the latency in the start of transmission of data.
假设动态提供了正确的 SYN-seq 和 ack 编号，是否可以进行系统调用或编写内核模块以将 tcp 连接直接进入 ESTABLISHED 状态，而无需经过三向握手过程？
您可能想看看 TCP fast open，现代 Linux 内核实现了：
TCP Fast Open (TFO) is an extension to speed up the opening of successive Transmission Control Protocol (TCP) connections between two endpoints. It works by using a TFO cookie (a TCP option) in the initial SYN packet to authenticate a previously connected client. If successful, it may start sending data to the client before the receipt of the final ACK packet of the three way handshake is received, skipping a round trip and lowering the latency in the start of transmission of data.