问题：如何扩大之前的通信框架，使其反对 UDP 通信，进而成为一个欠缺的网络通讯框架？
UDP 通信扩大
UDP 通信实体概要设计
- 每个 UDP Point 位置对等（因为不用被动发动连贯），可通过 ip 地址和 port 号进行通信
- UDP Point 数据收发单位为： Message 或 Byte
- 在承受口设计上，与 TcpClient 保持一致（框架接口一致性）
- 指标：封装原生 socket 细节，关注 UDP 通信逻辑
UDP 通信实体接口设计
typedef void UdpPoint;UdpPoint *UdpPoint_New(int port);UdpPoint *UdpPoint_From(int fd);void UdpPoint_Del(UdpPoint *point);int UdpPoint_SendMsg(UdpPoint *point, Message *msg, const char *remote, int port);int UdpPoint_SendRaw(UdpPoint *point, const char *buf, int length, const char *remote, int port);Message *UdpPoint_RecvMsg(UdpPoint *point, char *remote, int *port);int UdpPoint_RecvRaw((UdpPoint *point, const char *buf, int length, char *remote, int *port);int UdpPoint_Available(UdpPoint *point);void UdpPoint_SetData(UdpPoint *point, void *data);void *UdpPoint_GetData(UdpPoint *point);int UdpPoint_SetOpt(UdpPoint *point, int levle, int optname, const void *optval, unsigned int optlen);int UdpPoint_GetOpt(UdpPoint *point, int levle, int optname, void *optval, unsigned int *optlen);要害代码实现
- 因为 UDP 是以数据报形式进行通信（非数据流形式，报文间有显著边界）
- 因而，不能间接通过 MParser_ReadFd(...) 解析出音讯
- 必须先将报文残缺接管到内存中，再进行从内存中解析出音讯
- 即通过 MParser_ReadMeme(...) 间接实现音讯解析
对于上述的补充
UDP 套接字的收发报文要用 sendto 和 recvfrom（能够类比 TCP 套接字的 connect 和 accept），参数外面会标识要发往的对端，或者要接管的对端的 IP 地址和端口；
对 UDP 套接字 connect 的行为也只会通知内核：”帮我做个过滤，我只关怀这个对端的报文“，已”连贯“的UDP套接字能够利用 read, write， recv, send 函数，通常如果确定了该实体只与一个对端进行通信，那么就抉择 connect；
[更重要的是 UDP 套接字的缓冲区是以一个个报文为单位进行排队的]，调用一次 recvfrom 示意提取一个报文，和基于 TCP 基于字节流的形式是不同的。基于这样的起因咱们不能在 UDP 中先读取肯定的应用层 header, 而后再依据头部长度字段来优雅的读取具体数量的数据，这样会出错，产生凌乱，而在 TCP 中常常这么做。
编程试验： UDP 通信端设计与实现
udp_point.h
#ifndef UDP_POINT_H#define UDP_POINT_H#include "message.h"typedef void UdpPoint;UdpPoint *UdpPoint_New(int port);UdpPoint *UdpPoint_From(int fd);void UdpPoint_Del(UdpPoint *point);int UdpPoint_SendMsg(UdpPoint *point, Message *msg, const char *remote, int port);int UdpPoint_SendRaw(UdpPoint *point, const char *buf, int length, const char *remote, int port);Message *UdpPoint_RecvMsg(UdpPoint *point, char *remote, int *port);int UdpPoint_RecvRaw(UdpPoint *point, char *buf, int length, char *remote, int *port);int UdpPoint_Available(UdpPoint *point);void UdpPoint_SetData(UdpPoint *point, void *data);void *UdpPoint_GetData(UdpPoint *point);int UdpPoint_SetOpt(UdpPoint *point, int levle, int optname, const void *optval, unsigned int optlen);int UdpPoint_GetOpt(UdpPoint *point, int levle, int optname, void *optval, unsigned int *optlen);#endif // UDP_POINT_Hudp_point.c
#include "udp_point.h"#include "msg_parser.h"#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netinet/tcp.h>#include <arpa/inet.h>#include <unistd.h>#include <malloc.h>#include <string.h>typedef struct udp_point { int fd; MParser *parser; void *data;}Point;static char g_temp[1024 * 4] = {0};static void ParserAddr(struct sockaddr_in addr, char *ip, int *port){ if (ip) { strcpy(ip, inet_ntoa(addr.sin_addr)); } if (port) { *port = ntohs(addr.sin_port); }}UdpPoint *UdpPoint_New(int port){ Point *ret = malloc(sizeof(Point)); struct sockaddr_in addr = {0}; int ok = !! ret; addr.sin_family = AF_INET; addr.sin_addr.s_addr = htonl(INADDR_ANY); addr.sin_port = htons(port); ok = ok && ((ret->parser = MParser_New()) != NULL); ok = ok && ((ret->fd = socket(PF_INET, SOCK_DGRAM, 0)) != -1); ok = ok && (bind(ret->fd, (struct sockaddr*)&addr, sizeof(addr)) != -1); if (ok) { ret->data = NULL; } else { ret ? (MParser_Del(ret->parser), NULL) : NULL; ret ? close(ret->fd) : -1; free(ret); ret = NULL; } return ret;}UdpPoint *UdpPoint_From(int fd){ Point *ret = malloc(sizeof(Point)); if (ret) { ret->fd = fd; ret->parser = MParser_New(); ret->data = NULL; } return (ret && ret->parser) ? ret : (free(ret), NULL);}void UdpPoint_Del(UdpPoint *point){ Point *c = (Point*)point; if (c) { close(c->fd); MParser_Del(c->parser); free(c); }}int UdpPoint_SendMsg(UdpPoint *point, Message *msg, const char *remote, int port){ int ret = 0; Point *c = (Point*)point; if (c && msg && remote) { int len = Message_Size(msg); char *data = (char*)Message_H2N(msg); ret = UdpPoint_SendRaw(point, data, len, remote, port); Message_N2H(msg); } return ret; }int UdpPoint_SendRaw(UdpPoint *point, const char *buf, int length, const char *remote, int port){ int ret = 0; Point *c = (Point*)point; if (c && buf && remote) { struct sockaddr_in raddr = {0}; int addrlen = sizeof(raddr); raddr.sin_family = AF_INET; raddr.sin_addr.s_addr = inet_addr(remote); raddr.sin_port = htons(port); ret = (sendto(c->fd, buf, length, 0, (struct sockaddr*)&raddr, addrlen) != -1); } return ret;}Message *UdpPoint_RecvMsg(UdpPoint *point, char *remote, int *port){ Message *ret = NULL; Point *c = (Point*)point; if (c) { struct sockaddr_in raddr = {0}; int addrlen = sizeof(raddr); int length = recvfrom(c->fd, g_temp, sizeof(g_temp), MSG_PEEK, (struct sockaddr*)&raddr, &addrlen); char *buf = (length > 0) ? malloc(length) : NULL; length = recvfrom(c->fd, buf, length, 0, (struct sockaddr*)&raddr, &addrlen); if (length > 0) { ret = MParser_ReadMem(c->parser, buf, length); } if (ret) { ParserAddr(raddr, remote, port); } free(buf); } return ret;}int UdpPoint_RecvRaw(UdpPoint *point, char *buf, int length, char *remote, int *port){ int ret = 0; Point *c = (Point*)point; if (c && buf) { struct sockaddr_in raddr = {0}; int addrlen = sizeof(raddr); printf("===============================\n"); ret = recvfrom(c->fd, buf, length, 0, (struct sockaddr*)&raddr, &addrlen); printf("===============================\n"); if (ret != -1) { ParserAddr(raddr, remote, port); } } return ret;}int UdpPoint_Available(UdpPoint *point){ int ret = -1; Point *c = (Point*)point; if (c) { struct sockaddr_in raddr = {0}; int len = sizeof(raddr); ret = recvfrom(c->fd, g_temp, sizeof(g_temp), MSG_PEEK | MSG_DONTWAIT, (struct sockaddr*)&raddr, &len); } return ret; }void UdpPoint_SetData(UdpPoint *point, void *data){ Point *c = (Point*)point; if (c) { c->data = data; }}void *UdpPoint_GetData(UdpPoint *point){ void *ret = NULL; Point *c = (Point*)point; if (c) { ret = c->data; } return ret;}int UdpPoint_SetOpt(UdpPoint *point, int levle, int optname, const void *optval, unsigned int optlen){ int ret = -1; Point *c = (Point*)point; if (c) { ret = setsockopt(c->fd, levle, optname, optval, optlen); } return ret;}int UdpPoint_GetOpt(UdpPoint *point, int levle, int optname, void *optval, unsigned int *optlen){ int ret = -1; Point *c = (Point*)point; if (c) { ret = getsockopt(c->fd, levle, optname, optval, optlen); } return ret; }输入：
p = 0x55bd81ba4260ip: 192.168.2.24, port: 7777msg: 0x55bd81ba46e0msg->type = 1msg->cmd = 2msg->index = 3msg->total = 403 02 01tcp_client 增加属性相干操作
int TcpClient_SetOpt(TcpClient *client, int levle, int optname, const void *optval, unsigned int optlen);int TcpClient_GetOpt(TcpClient *client, int levle, int optname, void *optval, unsigned int *optlen);// ...int TcpClient_SetOpt(TcpClient *client, int levle, int optname, const void *optval, unsigned int optlen){ int ret = -1; Client *c = (Client*)client; if (c) { ret = setsockopt(c->fd, levle, optname, optval, optlen); } return ret;}int TcpClient_GetOpt(TcpClient *client, int levle, int optname, void *optval, unsigned int *optlen){ int ret = -1; Client *c = (Client*)client; if (c) { ret = getsockopt(c->fd, levle, optname, optval, optlen); } return ret; }tcp_server 增加属性相干操作
int TcpClient_SetOpt(TcpServer *server, int levle, int optname, const void *optval, unsigned int optlen);int TcpClient_GetOpt(TcpServer *server, int levle, int optname, void *optval, unsigned int *optlen);// ...int TcpServer_SetOpt(TcpServer *server, int levle, int optname, const void *optval, unsigned int optlen){ int ret = -1; Server *s = (Server*)server; if (s) { ret = setsockopt(s->fd, levle, optname, optval, optlen); } return ret;}int TcpServer_GetOpt(TcpServer *server, int levle, int optname, void *optval, unsigned int *optlen){ int ret = -1; Server *s = (Server*)server; if (s) { ret = getsockopt(s->fd, levle, optname, optval, optlen); } return ret; }