理解TCP/UDP

Love The Way You Lie 2024-04-17 20:45 67阅读 0赞

1:  IP层是面向消息的，不可靠的协议。是解决数据传输中的路径选择问题

2：TCP/UDP 决定了主机之间的数据传输方式。

3： server and  Client

## Server ##

1.  Initialize Winsock   2。  Create a socket Bind the socket.         3     Listen on the socket for a client. 4   Accept a connection from a client.  5 Receive and send data   6 Disconnect.

## Client ##

1.Initialize Winsock  2.Create a socket   3.Connect to the server  4.Send and receive data     5.Disconnect

4.WSDA结构体

typedef struct WSAData {
      WORD           wVersion;
      WORD           wHighVersion;
      unsigned short iMaxSockets;
      unsigned short iMaxUdpDg;
      char           *lpVendorInfo;
      char           szDescription[WSADESCRIPTION_LEN + 1];
      char           szSystemStatus[WSASYS_STATUS_LEN + 1];
      char           szDescription[WSADESCRIPTION_LEN + 1];
      unsigned short iMaxSockets;
      unsigned short iMaxUdpDg;
      char           *lpVendorInfo;
    } WSADATA;

5.WSAStartup 结构体

int WSAStartup(
      WORD      wVersionRequired,
      LPWSADATA lpWSAData
    );

`wVersionRequired`

TBD

`lpWSAData`

A pointer to the [WSADATA][] data structure that is to receive details of the Windows Sockets implementation.

If successful, the **WSAStartup** function returns zero. Otherwise, it returns one of the error codes listed below.

各种常见错误：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjUyODA4OQ_size_16_color_FFFFFF_t_70][]

6.结构体：addinfo

typedef struct addrinfo {
      int             ai_flags;
      int             ai_family;
      int             ai_socktype;
      int             ai_protocol;
      size_t          ai_addrlen;
      char            *ai_canonname;
      struct sockaddr *ai_addr;
      struct addrinfo *ai_next;
    } ADDRINFOA, *PADDRINFOA;

7.结构体：sockaddr

struct sockaddr {
            ushort  sa_family;
            char    sa_data[14];
    };
    
    struct sockaddr_in {
            short   sin_family;
            u_short sin_port;
            struct  in_addr sin_addr;
            char    sin_zero[8];
    };

[WSADATA]: https://docs.microsoft.com/windows/desktop/api/winsock/ns-winsock-wsadata
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjUyODA4OQ_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/53a4fdfe390242e284b445c9d9e2e643.png