11、TCP实现技术详解

TCP实现技术详解

1. 数据传输与MTU

在网络中，如果某个中间链路的最大传输单元（MTU）较低，发送方可能会传输比预期更少的数据，以避免数据分片。

2. TCP状态定义

TCP的每个状态都通过枚举和字符串进行定义，用于诊断打印。以下是TCP状态的定义：

/* TCP states */
#define TSTATE_STRINGS \
    "closed",       "SYN rcvd",     "established", \
    "close wait",   "last ACK",     "reset rcvd",   \
    "active open",  "ARP sent",     "ARP rcvd",     "SYN sent", \
    "active close", "FIN wait 1",   "FIN wait 2",   "closing",\
    "timed wait"
typedef enum {
    /* Passive open & close */
    TCP_CLOSED,              /* Closed */
    TCP_SYNR,                /* SYN recvd: send SYN ACK */
    TCP_EST,                 /* Established: connection OK */
    TCP_CLWAIT,              /* Close wait: FIN recvd, send data then FIN AC