1、前言
网络编程分为客户端和服务端，服务器通常分为迭代服务器和并发服务器。并发服务器可以根据多进程或多线程进行细分，给每个连接创建一个独立的进程或线程，或者预先分配好多个进程或线程等待连接的请求。今天探讨三种设计范式
（1）迭代服务器
（2）并发服务器，为每个客户请求创建一个进程或线程
（3）预先分配子进程或线程，每个子进程或线程调用accept
3、测试用例：
客户端代码：
1 #include <sys/wait.h>
2 #include <string.h>
3 #include <errno.h>
4 #include <netdb.h>
5 #include <stdlib.h>
6
7 #define IP "127.0.0.1"
8 #define PORT 8888
9 #define WORKER 4
10 #define MAXIN 4096
11 #define MAXLINE 4096
12
13 int tcp_connect(const char *host, const char *port)
14 {
15 if (host == NULL || port == NULL) {
16 return -1;
17 }
18 int sockfd, n;
19 struct addrinfo hints, *res, *ressave;
20 bzero(&hints, sizeof(struct addrinfo));
21 hints.ai_family = AF_UNSPEC;
22 hints.ai_socktype = SOCK_STREAM;
23 if ((n = getaddrinfo(host, port, &hints, &res)) != 0) {
24 printf("tcp_connect error for %s,%s: %s\n", host, port, strerror(errno));
25 return -1;
26 }
27 ressave = res;
28 do {
29 sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
30 if (sockfd < 0) {
31 continue;
32 }
33 if (connect(sockfd, res->ai_addr, res->ai_addrlen) == 0) {
34 break;
35 }
36 close(sockfd);
37 } while( (res = res->ai_next) != NULL);
38 if (res == NULL) {
39 printf("tcp_connect error for %s,%s: %s", host, port, strerror(errno));
40 return -1;
41 }
42 freeaddrinfo(ressave);
43 return sockfd;
44 }
45
46 int main(int argc, char **argv)
47 {
48 if (argc != 6) {
49 printf("usage: client <hostname or IPaddr> <port> <#children> <#loops/child> <#bytes/request>\n");
50 return -1;
51 }
52
53 int i, j, fd, nchildlen, nloops, nbytes;
54 pid_t pid;
55 ssize_t n;
56 char request[MAXLINE], reply[MAXIN];
57 nchildlen = atoi(argv[3]);
58 nloops = atoi(argv[4]);
59 nbytes = atoi(argv[5]);
60 snprintf(request, sizeof(request), "%d\n", nbytes);
61 for (i = 0; i < nchildlen; i++) {
62 if ((pid = fork()) == 0) {
63 for (j = 0; j < nloops; j++) {
64 fd = tcp_connect(argv[1], argv[2]);
65 if (fd > 0) {
66 write(fd, request, strlen(request));
67
68 if ((n = read(fd, reply, nbytes)) != nbytes) {
69 printf("read from server is:%s\n", reply);
70 }
71 close(fd);
72 } else {
73 break;
74 }
75 }
76 printf("child %d done\n", i);
77 exit(0);
78 }
79 }
80 /*waits all child process*/
81 while (wait(NULL) > 0)
82 ;
83 if (errno != ECHILD) {
84 fprintf(stderr, "wait error");
85 return -1;
86 }
87 return 0;
88 }
迭代服务器代码如下：
1 #include <stdio.h>
2 #include <unistd.h>
3 #include <sys/types.h>
4 #include <sys/socket.h>
5 #include <netinet/in.h>
6 #include <arpa/inet.h>
7 #include <assert.h>
8 #include <string.h>
9 #include <errno.h>
10
11 #define IP "127.0.0.1"
12 #define PORT 8888
13 #define MAXLINE 4096
14
15 int main()
16 {
17 int listenfd, connfd;
18 struct sockaddr_in address, client_addr;
19 socklen_t client_addrlen = sizeof(client_addr);
20 bzero(&address, sizeof(address));
21 address.sin_family = AF_INET;
22 inet_pton( AF_INET, IP, &address.sin_addr);
23 address.sin_port = htons(PORT);
24 listenfd = socket(PF_INET, SOCK_STREAM, 0);
25 assert(listenfd >= 0);
26 int ret = bind(listenfd, (struct sockaddr*)&address, sizeof(address));
27 assert(ret != -1);
28 ret = listen(listenfd, 5);
29 assert(ret != -1);
30
31 char buffer[MAXLINE];
32 while (1) {
33 printf("begin to accept.\n");
34 int connfd = accept( listenfd, ( struct sockaddr* )&client_addr, &client_addrlen );
35 if (connfd != -1) {
36 printf("accept a connection success.ip :%s, port :%d\n", inet_ntoa(client_addr.sin_addr), client_addr.sin_port);
37 } else {
38 printf("accept a connection failed,error:%s", strerror(errno));
39 }
40
41 int nbytes = read(connfd, buffer, MAXLINE);
42 printf("read from client is:%s\n", buffer);
43 write(connfd, buffer, nbytes);
44
45 close(connfd);
46 }
47 return 0;
48 }
并发服务器，为每个客户请求创建一个进程测试代码如下：
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <sys/wait.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#define IP "127.0.0.1"
#define PORT 8888
#define MAXLINE 4096
int main()
{
int count = 0;
struct sockaddr_in address, client_addr;
socklen_t client_addrlen = sizeof( client_addr );
bzero(&address, sizeof(address));
address.sin_family = AF_INET;
inet_pton( AF_INET, IP, &address.sin_addr);
address.sin_port = htons(PORT);
int listenfd,connfd;
listenfd = socket(PF_INET, SOCK_STREAM, 0);
assert(listenfd >= 0);
int ret = bind(listenfd, (struct sockaddr*)&address, sizeof(address));
assert(ret != -1);
ret = listen(listenfd, 5);
assert(ret != -1);
while(1) {
connfd = accept( listenfd, ( struct sockaddr* )&client_addr, &client_addrlen );
if (connfd == -1) {
printf("accept a connection failed,error:%s", strerror(errno));
break;
}
printf("accept a connection success.ip: %s,prot: %d\n",inet_ntoa(client_addr.sin_addr),client_addr.sin_port);
pid_t pid = fork();
count = count + 1;
/*child process */
if (pid == 0) {
printf("Create process %d handle a new connetcion.\n", count);
close(listenfd);
char buffer[MAXLINE];
int nbytes = read(connfd, buffer, MAXLINE);
printf("read from client is:%s\n", buffer);
write(connfd, buffer, nbytes);
exit(0);
}
if (pid < 0) {
printf("fork error");
}
close(connfd);
}
return 0;
}
预先分配子进程，每个子进程调用accept测试代码如下：
1 #include <stdio.h>
2 #include <unistd.h>
3 #include <sys/types.h>
4 #include <sys/socket.h>
5 #include <netinet/in.h>
6 #include <arpa/inet.h>
7 #include <assert.h>
8 #include <sys/wait.h>
9 #include <string.h>
10 #include <errno.h>
11 #include <stdlib.h>
12
13 #define IP "127.0.0.1"
14 #define PORT 8888
15 #define WORKER 4
16 #define MAXLINE 4096
17
18 int worker(int listenfd, int i)
19 {
20 while (1) {
21 printf("I am worker %d, begin to accept connection.\n", i);
22 struct sockaddr_in client_addr;
23 socklen_t client_addrlen = sizeof( client_addr );
24 int connfd = accept( listenfd, ( struct sockaddr* )&client_addr, &client_addrlen );
25 if (connfd != -1) {
26 printf("worker %d accept a connection success. ip:%s, prot:%d\n", i, inet_ntoa(client_addr.sin_addr), client_addr.sin_port);
27 } else {
28 printf("worker %d accept a connection failed,error:%s", i, strerror(errno));
29 }
30 char buffer[MAXLINE];
31 int nbytes = read(connfd, buffer, MAXLINE);
32 printf("read from client is:%s\n", buffer);
33 write(connfd, buffer, nbytes);
34 close(connfd);
35 }
36 return 0;
37 }
38
39 int main()
40 {
41 int i = 0;
42 struct sockaddr_in address;
43 bzero(&address, sizeof(address));
44 address.sin_family = AF_INET;
45 inet_pton( AF_INET, IP, &address.sin_addr);
46 address.sin_port = htons(PORT);
47 int listenfd = socket(PF_INET, SOCK_STREAM, 0);
48 assert(listenfd >= 0);
49 int ret = bind(listenfd, (struct sockaddr*)&address, sizeof(address));
50 assert(ret != -1);
51 ret = listen(listenfd, 5);
52 assert(ret != -1);
53
54 for (i = 0; i < WORKER; i++) {
55 printf("Create worker %d\n", i+1);
56 pid_t pid = fork();
57 /*child process */
58 if (pid == 0) {
59 worker(listenfd, i);
60 }
61 if (pid < 0) {
62 printf("fork error");
63 }
64 }
65 /*wait child process*/
66 while (wait(NULL) != 0)
67 ;
68 if (errno == ECHILD) {
69 fprintf(stderr, "wait error:%s\n", strerror(errno));
70 }
71 return 0;
72 }
时间： 2024-08-04 22:21:48