P92 5.2 TCP 原理

ch05/op_client.c

@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#define BUF_SIZE 1024
+#define RLT_SIZE 4
+#define OPSZ 4
+void error_handling(char *message);
+
+int main(int argc, char *argv[])
+{
+    int sock;
+    char opmsg[BUF_SIZE];
+    int result, opnd_cnt, i;
+    struct sockaddr_in serv_adr;
+    if (argc != 3)
+    {
+        printf("Usage : %s <IP> <port>\n", argv[0]);
+        exit(1);
+    }
+
+    sock = socket(PF_INET, SOCK_STREAM, 0);
+    if (sock == -1)
+        error_handling("socket() error");
+
+    memset(&serv_adr, 0, sizeof(serv_adr));
+    serv_adr.sin_family = AF_INET;
+    serv_adr.sin_addr.s_addr = inet_addr(argv[1]);
+    serv_adr.sin_port = htons(atoi(argv[2]));
+
+    if (connect(sock, (struct sockaddr *)&serv_adr, sizeof(serv_adr)) == -1)
+        error_handling("connect() error!");
+    else
+        puts("Connected...........");
+
+    fputs("Operand count: ", stdout);
+    scanf("%d", &opnd_cnt);
+    opmsg[0] = (char)opnd_cnt;
+
+    for (i = 0; i < opnd_cnt; i++)
+    {
+        printf("Operand %d: ", i + 1);
+        scanf("%d", (int *)&opmsg[i * OPSZ + 1]);
+    }
+    fgetc(stdin);
+    fputs("Operator: ", stdout);
+    scanf("%c", &opmsg[opnd_cnt * OPSZ + 1]);
+    write(sock, opmsg, opnd_cnt * OPSZ + 2);
+    read(sock, &result, RLT_SIZE);
+
+    printf("Operation result: %d \n", result);
+    close(sock);
+    return 0;
+}
+
+void error_handling(char *message)
+{
+    fputs(message, stderr);
+    fputc('\n', stderr);
+    exit(1);
+}

ch05/op_server.c

@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#define BUF_SIZE 1024
+#define OPSZ 4
+void error_handling(char *message);
+int calculate(int opnum, int opnds[], char oprator);
+int main(int argc, char *argv[])
+{
+    int serv_sock, clnt_sock;
+    char opinfo[BUF_SIZE];
+    int result, opnd_cnt, i;
+    int recv_cnt, recv_len;
+    struct sockaddr_in serv_adr, clnt_adr;
+    socklen_t clnt_adr_sz;
+    if (argc != 2)
+    {
+        printf("Usage : %s <port>\n", argv[0]);
+        exit(1);
+    }
+
+    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
+    if (serv_sock == -1)
+        error_handling("socket() error");
+
+    memset(&serv_adr, 0, sizeof(serv_adr));
+    serv_adr.sin_family = AF_INET;
+    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
+    serv_adr.sin_port = htons(atoi(argv[1]));
+
+    if (bind(serv_sock, (struct sockaddr *)&serv_adr, sizeof(serv_adr)) == -1)
+        error_handling("bind() error");
+    if (listen(serv_sock, 5) == -1)
+        error_handling("listen() error");
+    clnt_adr_sz = sizeof(clnt_adr);
+    for (int i = 0; i < 5; i++)
+    {
+        opnd_cnt = 0;
+        clnt_sock = accept(serv_sock, (struct sockaddr *)&clnt_adr, &clnt_adr_sz);
+        read(clnt_sock, &opnd_cnt, 1);
+
+        recv_len = 0;
+        while ((opnd_cnt * OPSZ + 1) > recv_len)
+        {
+            recv_cnt = read(clnt_sock, &opinfo[recv_len], BUF_SIZE - 1);
+            recv_len += recv_cnt;
+        }
+        result = calculate(opnd_cnt, (int *)opinfo, opinfo[recv_len - 1]);
+        write(clnt_sock, (char *)&result, sizeof(result));
+        close(clnt_sock);
+    }
+    close(serv_sock);
+    return 0;
+}
+int calculate(int opnum, int opnds[], char op)
+{
+    int result = opnds[0], i;
+    switch (op)
+    {
+    case '+':
+        for (i = 1; i < opnum; i++)
+            result += opnds[i];
+        break;
+    case '-':
+        for (i = 1; i < opnum; i++)
+            result -= opnds[i];
+        break;
+    case '*':
+        for (i = 1; i < opnum; i++)
+            result *= opnds[i];
+        break;
+    }
+    return result;
+}
+void error_handling(char *message)
+{
+    fputs(message, stderr);
+    fputc('\n', stderr);
+    exit(1);
+}