? ? ? ?使用C简单的实现一个tcp?server，包括常规server、多线程实现server、select实现server、poll实现server、epoll实现server。
常规模式
#define MAXLEN 4096
int main(int argc, char **argv) {
int listenfd, connfd, n;
struct sockaddr_in servaddr;
char buff[MAXLEN];
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(9999);
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
if (listen(listenfd, 10) != 0) {
printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
struct sockaddr_in client;
socklen_t len = sizeof(client);
if ((connfd = accept(listenfd, (struct sockaddr *)&client, &len)) == -1) {
printf("accept socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
printf("========waiting for client's request========\n");
while (1) {
n = recv(connfd, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
send(connfd, buff, n, 0);
} else if (n == 0) {
close(connfd);
}
close(listenfd);
return 0;
}
?多线程模式
? ? ? ? 支持多个客户端并发连接。
#define MAXLEN 4096
void *client_routine(void *arg) {
int connfd = *(int *)arg;
char buff[MAXLEN];
while (1) {
int n = recv(connfd, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
send(connfd, buff, n, 0);
} else if (n == 0) {
close(connfd);
break;
}
}
return NULL;
}
int main(int argc, char **argv) {
int listenfd, connfd, n;
struct sockaddr_in servaddr;
char buff[MAXLEN];
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(9999);
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
if (listen(listenfd, 10) != 0) {
printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
while (1) {
struct sockaddr_in client;
socklen_t len = sizeof(client);
if ((connfd = accept(listenfd, (struct sockaddr *)&client, &len)) == -1) {
printf("accept socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
pthread_t threadid;
pthread_create(&threadid, NULL, client_routine, (void *)&connfd);
}
close(listenfd);
return 0;
}
select模式
? ? ? ? 单线程支持多个客户端连接。
#define MAXLEN 4096
void *client_routine(void *arg) {
int connfd = *(int *)arg;
char buff[MAXLEN];
while (1) {
int n = recv(connfd, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
send(connfd, buff, n, 0);
} else if (n == 0) {
close(connfd);
break;
}
}
return NULL;
}
int main(int argc, char **argv) {
int listenfd, connfd, n;
struct sockaddr_in servaddr;
char buff[MAXLEN];
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(9999);
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
if (listen(listenfd, 10) != 0) {
printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
fd_set rfds, rset, wfds, wset;
FD_ZERO(&rfds); /*将rfds清零使集合中不含任何fd*/
FD_SET(listenfd, &rfds); /*将fd加入rfds集合*/
FD_ZERO(&wfds);
int max_fd = listenfd;
while (1) {
rset = rfds;
wset = wfds;
int nready = select(max_fd + 1, &rset, &wset, NULL, NULL);
/*在调用select()函数后，用FD_ISSET来检测fd是否在set集合中，当检测到fd在set中则返回真，否则，返回假（0）*/
if (FD_ISSET(listenfd, &rset)) {
struct sockaddr_in client;
socklen_t len = sizeof(client);
if ((connfd = accept(listenfd, (struct sockaddr *)&client, &len)) == 1) {
printf("accept socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
FD_SET(connfd, &rfds);
if (connfd > max_fd) max_fd = connfd;
if (--nready == 0) continue;
}
int i = 0;
for (i = listenfd + 1; i <= max_fd; i++) {
if (FD_ISSET(i, &rset)) {
n = recv(i, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
FD_SET(i, &wfds);
} else if (n == 0) {
FD_CLR(i, &rfds); /*将fd从set集合中清除*/
close(i);
}
if (--nready == 0) break;
} else if (FD_ISSET(i, &wset)) {
send(i, buff, n, 0);
FD_SET(i, &rfds);
FD_CLR(i, &wfds); /*将fd从wfds集合中清除*/
}
}
}
close(listenfd);
return 0;
}
?
poll 模式
#define MAXLEN 4096
void *client_routine(void *arg) {
int connfd = *(int *)arg;
char buff[MAXLEN];
while (1) {
int n = recv(connfd, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
send(connfd, buff, n, 0);
} else if (n == 0) {
close(connfd);
break;
}
}
return NULL;
}
int main(int argc, char **argv) {
int listenfd, connfd, n;
struct sockaddr_in servaddr;
char buff[MAXLEN];
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(9999);
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
if (listen(listenfd, 10) != 0) {
printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
struct pollfd fds[POLL_SIZE] = {0};
fds[0].fd = listenfd;
fds[0].events = POLLIN;
int max_fd = listenfd;
int i = 0;
for (i = 1; i < POLL_SIZE; i++) {
fds[i].fd = -1;
}
while (1) {
int nready = poll(fds, max_fd + 1, -1);
printf("nready: %d \n", nready);
if (fds[0].revents & POLLIN) {
struct sockaddr_in client;
socklen_t len = sizeof(client);
if ((connfd = accept(listenfd, (struct sockaddr *)&client, &len)) == -1) {
printf("accept socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
printf("accept \n");
fds[connfd].fd = connfd;
fds[connfd].events = POLLIN;
if (connfd > max_fd) max_fd = connfd;
if (--nready == 0) continue;
}
for (i = listenfd + 1; i <= max_fd; i++) {
if (fds[i].revents & POLLIN) {
n = recv(i, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
fds[i].events = POLLOUT;
// send(i, buff, n, 0);
} else if (n == 0) {
fds[i].fd = -1;
close(i);
}
if (--nready == 0) break;
} else if (fds[i].revents & POLLOUT) {
send(i, buff, n, 0);
fds[i].events = POLLIN;
}
}
}
close(listenfd);
return 0;
}
epoll模式
#define MAXLEN 4096
void *client_routine(void *arg) {
int connfd = *(int *)arg;
char buff[MAXLEN];
while (1) {
int n = recv(connfd, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
send(connfd, buff, n, 0);
} else if (n == 0) {
close(connfd);
break;
}
}
return NULL;
}
int main(int argc, char **argv) {
int listenfd, connfd, n;
struct sockaddr_in servaddr;
char buff[MAXLEN];
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(9999);
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
if (listen(listenfd, 10) != 0) {
printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
return 0;
}
int epfd = epoll_create(1); // init size
struct epoll_event events[POLL_SIZE] = {0};
struct epoll_event ev;
ev.events = EPOLLIN;
ev.data.fd = listenfd;
epoll_ctl(epfd, EPOLL_CTL_ADD, listenfd, &ev);
while (1) {
int nready = epoll_wait(epfd, events, POLL_SIZE, 5);
if (nready == -1) {
continue;
}
int i = 0;
for (i = 0; i < nready; i++) {
int clientfd = events[i].data.fd;
if (clientfd == listenfd) {
struct sockaddr_in client;
socklen_t len = sizeof(client);
if ((connfd = accept(listenfd, (struct sockaddr *)&client, &len)) ==
-1) {
printf("accept socket error: %s(errno: %d)\n", strerror(errno),
errno);
return 0;
}
printf("accept\n");
ev.events = EPOLLIN;
ev.data.fd = connfd;
epoll_ctl(epfd, EPOLL_CTL_ADD, connfd, &ev);
} else if (events[i].events & EPOLLIN) {
n = recv(clientfd, buff, MAXLEN, 0);
if (n > 0) {
buff[n] = '\0';
printf("recv msg from client: %s\n", buff);
send(clientfd, buff, n, 0);
} else if (n == 0) {
ev.events = EPOLLIN;
ev.data.fd = clientfd;
epoll_ctl(epfd, EPOLL_CTL_DEL, clientfd, &ev);
close(clientfd);
}
}
}
}
close(listenfd);
return 0;
}