13-Openwrt libubox ustream

流缓冲管理,ustream_fd跟uloop_fd有什么不一样呢？ustream_fd内部其实就是uloop_fd，与fopen和open类似，fopen的内部也是open加上流缓冲管理。

struct ustream_fd {
    struct ustream stream;
    struct uloop_fd fd;
};

ustream相关的函数

void ustream_fd_init(struct ustream_fd *s, int fd)

void ustream_init_defaults(struct ustream *s)

void ustream_free(struct ustream *s)

ustream的应用在uhttpd的socket监听里面有使用到

bool uh_accept_client(int fd, bool tls)
{
    static struct client *next_client;
    struct client *cl;
    unsigned int sl; 
    int sfd;
    static int client_id = 0;
    struct sockaddr_in6 addr;

    if (!next_client)
        next_client = calloc(1, sizeof(*next_client));

    cl = next_client;

    sl = sizeof(addr);
    sfd = accept(fd, (struct sockaddr *) &addr, &sl);
    if (sfd < 0)
        return false;

    set_addr(&cl->peer_addr, &addr);
    sl = sizeof(addr);
    getsockname(sfd, (struct sockaddr *) &addr, &sl);
    set_addr(&cl->srv_addr, &addr);

    cl->us = &cl->sfd.stream;
    if (tls) {
        uh_tls_client_attach(cl);
    } else {
        cl->us->notify_read = client_ustream_read_cb;
        cl->us->notify_write = client_ustream_write_cb;
        cl->us->notify_state = client_notify_state;
    }

    cl->us->string_data = true;
    ustream_fd_init(&cl->sfd, sfd);

    uh_poll_connection(cl);
    list_add_tail(&cl->list, &clients);

    next_client = NULL;
    n_clients++;
    cl->id = client_id++;
    cl->tls = tls;

    return true;
}

ustream在socket上面的使用例子：

//客户端//
#include "std.h"
 
/* 在TCP连接持续多少秒没有报文往来之后则开始发送探测报文 */
int tcp_keepalive_time = 5;
/* TCP keepalive探测包的发送间隔 */
int tcp_keepalive_intvl = 5;
/* 在tcp_keepalive_time之后没有收到对方确认，继续发送保活探测包的次数 */
int tcp_keepalive_probes = 3;
 
int fd = -1;
struct ustream_fd ufd;                      // uloop机制监听的结构体
 
static void notify_read_cb(struct ustream *s, int bytes)
{
    char *data = NULL;
    int len;
 
    data = ustream_get_read_buf(s, &len);
    printf("eason recv data:%d available len:%d", bytes, len);
    if(!data){
        printf("eason recv packet len is too short, wait more data");
        return;
    }
 
    ustream_consume(s, len);
}
 
/**************************************************************************************
* FunctionName   : notify_state_cb()
* Description    : uloop+ustream框架通知连接状态发生变化的回调,如果检测到对端断开则本地断开连接
* EntryParameter : 指向当前活跃的ustream的指针
* ReturnValue    : NULL
**************************************************************************************/
static void notify_state_cb(struct ustream *s)
{
    if (!s->eof) return;
    printf("eason misock client got eof!, pending:%d", s->w.data_bytes);
	close(fd);
}
 
/**************************************************************************************
* FunctionName   : notify_write_cb()
* Description    : uloop+ustream框架通知缓冲数据已经被写入到stream中
* EntryParameter : 指向当前活跃的ustream的指针
* ReturnValue    : NULL
**************************************************************************************/
static void notify_write_cb(struct ustream *s, int bytes)
{
    printf("eason misock client wrote:%d bytes, pending:%d", bytes, s->w.data_bytes);
}
 
static void setup_misock_client_ustream()
{
    ufd.stream.string_data  = false;
    ufd.stream.notify_read  = notify_read_cb;
    ufd.stream.notify_state = notify_state_cb;
    ufd.stream.notify_write = notify_write_cb;
    ustream_fd_init(&ufd, fd);
}
 
int main(void)
{
	struct sockaddr_in server;
	int optval;
    struct timeval tval;
    fd_set r_set, w_set;
    int rc = 0;
	
	// 1.创建
	if (0 > (fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)))
		err_exit("socket");
	
	// 2.模式
    fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK); //设置非阻塞模式
 
	// 3.绑定
 
	// 4.连接
	memset(&server, 0, sizeof(server));
	server.sin_family = AF_INET;
	server.sin_port = htons(8888);
	server.sin_addr.s_addr = inet_addr("192.168.201.130");
	if (0 > connect(fd, (struct sockaddr *)&server, sizeof(server)))
		err_exit("connect");
	printf("connect success!\n");
 
 
	/* 4.KEEPALIVE相关配置 */
	/*使能keepalive*/
	optval =1;
	setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &optval, sizeof(optval));
	/* 配置tcp_keepalive_time */
	optval = tcp_keepalive_time;
	setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, &optval, sizeof(optval));
	/* 配置tcp_keepalive_intvl */
	optval = tcp_keepalive_intvl;
	setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, &optval, sizeof(optval));
	/* 配置tcp_keepalive_probes */
	optval = tcp_keepalive_probes;
	setsockopt(fd, SOL_TCP, TCP_KEEPCNT, &optval, sizeof(optval));
 
	// 4.确定连接已经成功
	FD_ZERO(&r_set);
	FD_SET(fd, &r_set);
	FD_ZERO(&w_set);
	FD_SET(fd, &w_set);
	tval.tv_sec  = 1;
	tval.tv_usec = 0;
 
	rc = select(fd+1, &r_set, &w_set, NULL, &tval);
	if(rc <= 0){
		printf("eason fun=%s,line=%d", __FUNCTION__,__LINE__);
		goto RETURN_1;
	}
 
	printf("eason connect fd=%d,%d,%d,%d",fd,rc,FD_ISSET(fd, &w_set),FD_ISSET(fd, &r_set));
	if (rc == 1 && FD_ISSET(fd, &w_set) && !FD_ISSET(fd, &r_set)) {
		printf("eason connected\n");
		setup_misock_client_ustream();
		return NULL; // connected
	}
	printf("eason connect failed fun=%s,line=%d", __FUNCTION__,__LINE__);
 
RETURN_1:
	// 10.关闭
	close(fd);
	return NULL;
	
#if 0	
	char send_buf[BUFSIZ];
	char recv_buf[BUFSIZ];
	int maxfd= -1;
	fd_set readfds;
	int ret=-1;
	int i;
	
	while(1) {
		FD_ZERO(&readfds);
 
		FD_SET(0, &readfds);
		maxfd = maxfd > 0 ? maxfd : 0;
		FD_SET(connfd, &readfds);
		maxfd = maxfd > connfd ? maxfd : connfd;
		
		if (0 > select(maxfd + 1, &readfds, NULL, NULL, NULL))
			err_exit("select");
 
		for (i=0; i<=maxfd; i++) 
		{
			if (FD_ISSET(i, &readfds)) 
			{
				if (0 == i) 
				{
					fgets(send_buf, sizeof(send_buf), stdin);		
					if (0 > send(connfd, send_buf, strlen(send_buf) + 1, 0))
						err_exit("send");				
				} 
				else if (connfd == i) 
				{
					if (0 > (ret = recv(connfd, recv_buf, BUFSIZ, 0)))
						err_exit("recv");
					else if (0 == ret) 
					{
						printf("server quit!\n");
						exit(0);
					}
					
					recv_buf[ret] = '\0';
					printf("server: %s\n", recv_buf);
				}
			}
		}
	}
	close(connfd);
	exit(0);
#endif	
}

另外在libubox里面也有自带一个例子：
位于/example/ustream-example.c

#include <sys/socket.h>
#include <netinet/in.h>

#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "ustream.h"
#include "uloop.h"
#include "usock.h"

static struct uloop_fd server;
static const char *port = "10000";
struct client *next_client = NULL;

struct client {
	struct sockaddr_in sin;

	struct ustream_fd s;
	int ctr;
};

static void client_read_cb(struct ustream *s, int bytes)
{
	struct client *cl = container_of(s, struct client, s.stream);
	struct ustream_buf *buf = s->r.head;
	char *newline, *str;

	do {
		str = ustream_get_read_buf(s, NULL);
		if (!str)
			break;

		newline = strchr(buf->data, '\n');
		if (!newline)
			break;

		*newline = 0;
		ustream_printf(s, "%s\n", str);
		ustream_consume(s, newline + 1 - str);
		cl->ctr += newline + 1 - str;
	} while(1);

	if (s->w.data_bytes > 256 && !ustream_read_blocked(s)) {
		fprintf(stderr, "Block read, bytes: %d\n", s->w.data_bytes);
		ustream_set_read_blocked(s, true);
	}
}

static void client_close(struct ustream *s)
{
	struct client *cl = container_of(s, struct client, s.stream);

	fprintf(stderr, "Connection closed\n");
	ustream_free(s);
	close(cl->s.fd.fd);
	free(cl);
}

static void client_notify_write(struct ustream *s, int bytes)
{
	fprintf(stderr, "Wrote %d bytes, pending: %d\n", bytes, s->w.data_bytes);

	if (s->w.data_bytes < 128 && ustream_read_blocked(s)) {
		fprintf(stderr, "Unblock read\n");
		ustream_set_read_blocked(s, false);
	}
}

static void client_notify_state(struct ustream *s)
{
	struct client *cl = container_of(s, struct client, s.stream);

	if (!s->eof)
		return;

	fprintf(stderr, "eof!, pending: %d, total: %d\n", s->w.data_bytes, cl->ctr);
	if (!s->w.data_bytes)
		return client_close(s);

}

static void server_cb(struct uloop_fd *fd, unsigned int events)
{
	struct client *cl;
	unsigned int sl = sizeof(struct sockaddr_in);
	int sfd;

	if (!next_client)
		next_client = calloc(1, sizeof(*next_client));

	cl = next_client;
	sfd = accept(server.fd, (struct sockaddr *) &cl->sin, &sl);
	if (sfd < 0) {
		fprintf(stderr, "Accept failed\n");
		return;
	}

	cl->s.stream.string_data = true;
	cl->s.stream.notify_read = client_read_cb;
	cl->s.stream.notify_state = client_notify_state;
	cl->s.stream.notify_write = client_notify_write;
	ustream_fd_init(&cl->s, sfd);
	next_client = NULL;
	fprintf(stderr, "New connection\n");
}

static int run_server(void)
{

	server.cb = server_cb;
	server.fd = usock(USOCK_TCP | USOCK_SERVER | USOCK_IPV4ONLY | USOCK_NUMERIC, "127.0.0.1", port);
	if (server.fd < 0) {
		perror("usock");
		return 1;
	}

	uloop_init();
	uloop_fd_add(&server, ULOOP_READ);
	uloop_run();

	return 0;
}

static int usage(const char *name)
{
	fprintf(stderr, "Usage: %s -p <port>\n", name);
	return 1;
}

int main(int argc, char **argv)
{
	int ch;

	while ((ch = getopt(argc, argv, "p:")) != -1) {
		switch(ch) {
		case 'p':
			port = optarg;
			break;
		default:
			return usage(argv[0]);
		}
	}

	return run_server();
}

参考文件
https://blog.csdn.net/TSZ0000/article/details/103558627

https://segmentfault.com/a/1190000012104130