From aa57b1e412dfe2ce6c473162a1cf47e967d3949a Mon Sep 17 00:00:00 2001
From: yangsoon <yangsoonlx@gmail.com>
Date: Sat, 23 May 2020 11:58:16 +0800
Subject: [PATCH] =?UTF-8?q?=E7=AE=80=E5=8D=95=E7=9A=84=E5=9B=9E=E5=B0=84?=
 =?UTF-8?q?=E4=BB=A3=E7=A0=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 muduo/unp/README.md             | 13 ++++++++
 muduo/unp/byteorder.c           | 23 -------------
 muduo/unp/daytimetcp/server.c   |  3 ++
 muduo/unp/tcpcliser/tcpcli01.c  | 23 +++++++++++++
 muduo/unp/tcpcliser/tcpserv01.c | 57 +++++++++++++++++++++++++++++++++
 5 files changed, 96 insertions(+), 23 deletions(-)
 create mode 100644 muduo/unp/README.md
 delete mode 100644 muduo/unp/byteorder.c
 create mode 100644 muduo/unp/tcpcliser/tcpcli01.c
 create mode 100644 muduo/unp/tcpcliser/tcpserv01.c

diff --git a/muduo/unp/README.md b/muduo/unp/README.md
new file mode 100644
index 0000000..fadc9da
--- /dev/null
+++ b/muduo/unp/README.md
@@ -0,0 +1,13 @@
+## UNP
+
+记录细碎的知识点
+
+### TCP客户/服务器程序示例
+网络连接的一些边界问题
+
+1. 客户和服务器启动时候发生了什么？
+2. 客户正常终止时发生了什么？
+3. 若服务器进程在客户之前终止，客户会发生什么？
+4. 若服务器主机崩溃，则客户发生什么？
+
+
diff --git a/muduo/unp/byteorder.c b/muduo/unp/byteorder.c
deleted file mode 100644
index d75109b..0000000
--- a/muduo/unp/byteorder.c
+++ /dev/null
@@ -1,23 +0,0 @@
-// byteorder.c
-#include "unp.h"
-
-int main(int argc, char *argv[]) {
-    union {
-        short s;
-        char c[sizeof(short)];
-    } un;
-    un.s = 0x0102;
-    printf("%s: ", CPU_VENDOR_OS);
-    if (sizeof(short) == 2) {
-        if (un.c[0] == 1 && un.c[1] == 2) {
-            printf("big-endian\n");
-        } else if (un.c[0] == 2 && un.c[1] == 1) {
-            printf("little-endian\n");
-        } else {
-            printf("unknown\n");
-        }
-    } else {
-        printf("sizeof(short) = %d\n", sizeof(short));
-    }
-    exit(0);
-}
\ No newline at end of file
diff --git a/muduo/unp/daytimetcp/server.c b/muduo/unp/daytimetcp/server.c
index b38ce43..43b82a6 100644
--- a/muduo/unp/daytimetcp/server.c
+++ b/muduo/unp/daytimetcp/server.c
@@ -67,6 +67,9 @@ int main(int argc, char **argv) {
         // 返回值是和参数3一致的如果不一样说明出错
         if (write(connfd, buff, sizeof(buff)) != sizeof(buff))
             err_sys("write error");
+
+        // 当调用close函数的时候 close函数尝试发送已排队等待发送到对端的数据 发送完毕后是正常的TCP的四次挥手
+        // 当调用close函数的时候 只有对应的socket 描述符的引用计数为0时 才会引发四次挥手
         if (close(connfd) == -1) 
             err_sys("close error");
     }
diff --git a/muduo/unp/tcpcliser/tcpcli01.c b/muduo/unp/tcpcliser/tcpcli01.c
new file mode 100644
index 0000000..b8a1354
--- /dev/null
+++ b/muduo/unp/tcpcliser/tcpcli01.c
@@ -0,0 +1,23 @@
+#include "unp.h"
+
+int main(int argc, char **argv) {
+    int sockfd;
+    struct sockaddr_in servaddr;
+    if(argc != 2){
+        err_quit("usage: tcpcli <IPaddress>");
+    }
+
+    sockfd = Socket(AF_INET, SOCK_STREAM, 0);
+    bzero(&servaddr, sizeof(servaddr));
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_port = htons(SERV_PORT);
+    Inet_pton(AF_INET, argv[1], &servaddr.sin_addr);
+    
+    if(connect(sockfd, (struct sockaddr*) &servaddr, sizeof(servaddr))<0) {
+        err_sys("connect error");
+    }
+
+    str_cli(stdin, sockfd);
+
+    exit(0);
+}
\ No newline at end of file
diff --git a/muduo/unp/tcpcliser/tcpserv01.c b/muduo/unp/tcpcliser/tcpserv01.c
new file mode 100644
index 0000000..59b9b4f
--- /dev/null
+++ b/muduo/unp/tcpcliser/tcpserv01.c
@@ -0,0 +1,57 @@
+#include "unp.h"
+
+void str_echo_local(int sockfd) {
+    ssize_t n;
+    char buf[MAXLINE];
+again:
+    // 如果客户端关闭连接 那么接收到客户端的FIN将导致read的返回值n=0，进而导致函数返回
+    while((n=read(sockfd, buf, MAXLINE))>0) {
+        Write(sockfd, buf, n);
+    }
+
+    if(n < 0 && errno == EINTR) {
+        goto again;
+    } else if (n < 0) {
+        err_sys("read error");
+    }
+}
+
+int main(int argc, char **argv) {
+    int listenfd, connfd;
+    pid_t childpid;
+    socklen_t clilen;
+    struct sockaddr_in servaddr, cliaddr;
+
+    if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+        err_sys("socket error");
+    }
+    bzero(&servaddr, sizeof(servaddr));
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+    servaddr.sin_port = htons(SERV_PORT);
+
+    if(bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0){
+        err_sys("bind error");
+    }
+
+    if(listen(listenfd, LISTENQ)<0) {
+        err_sys("listen error");
+    }
+
+    for(;;) {
+        clilen = sizeof(cliaddr);
+        connfd = accept(listenfd, (struct sockaddr *) &cliaddr, &clilen);
+
+        if((childpid = fork()) == 0) {
+            if(close(listenfd)<0) {
+                err_sys("listen error");
+            }
+            str_echo_local(connfd);
+            exit(0);
+        }
+
+        if(close(connfd)<0) {
+            err_sys("close error");
+        }
+    }
+}
\ No newline at end of file