ubus数据结构和接口介绍

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libubus
数据结构

struct ubus_event_handler {struct ubus_object obj;ubus_event_handler_t cb;};struct ubus_context {struct list_head requests;struct avl_tree objects;    /** client端object链表头 */struct list_head pending;struct uloop_fd sock;       /** client端sock对象 */uint32_t local_id;          /** ubusd分配的client id */uint16_t request_seq;int stack_depth;/** 断开连接回调函数 */void (*connection_lost)(struct ubus_context *ctx);struct {struct ubus_msghdr hdr;char data[UBUS_MAX_MSGLEN];} msgbuf;                   /** 通信报文 */};struct ubus_object_data {uint32_t id;uint32_t type_id;const char *path;struct blob_attr *signature;};struct ubus_request_data {uint32_t object;uint32_t peer;uint16_t seq;/* internal use */bool deferred;int fd;};struct ubus_request {struct list_head list;struct list_head pending;int status_code;bool status_msg;bool blocked;bool cancelled;bool notify;uint32_t peer;uint16_t seq;ubus_data_handler_t raw_data_cb;ubus_data_handler_t data_cb;ubus_fd_handler_t fd_cb;ubus_complete_handler_t complete_cb;struct ubus_context *ctx;void *priv;};struct ubus_notify_request {struct ubus_request req;ubus_notify_complete_handler_t status_cb;ubus_notify_complete_handler_t complete_cb;uint32_t pending;uint32_t id[UBUS_MAX_NOTIFY_PEERS + 1];};struct ubus_auto_conn {struct ubus_context ctx;struct uloop_timeout timer;const char *path;ubus_connect_handler_t cb;};

接口说明 

/*** 初始化client端context结构，并连接ubusd*/struct ubus_context *ubus_connect(const char *path)/*** 与ubus_connect()函数基本功能相同，但此函数在连接断开后会自动进行重连*/void ubus_auto_connect(struct ubus_auto_conn *conn)/*** 注册新事件*/int ubus_register_event_handler(struct ubus_context *ctx,struct ubus_event_handler *ev,const char *pattern)/*** 发出事件消息*/int ubus_send_event(struct ubus_context *ctx, const char *id,struct blob_attr *data)/*** 向ubusd查询指定UBUS_ATTR_OBJPATH对应对象信息内容* 内容通过输入回调函数ubus_lookup_handler_t由调用者自行处理*/int ubus_lookup(struct ubus_context *ctx, const char *path,ubus_lookup_handler_t cb, void *priv)/*** 向ubusd查询指定UBUS_ATTR_OBJPATH对应的ID号*/int ubus_lookup_id(struct ubus_context *ctx, const char *path, uint32_t *id)

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libubus-io 
接口说明 

/*** libubus关注的报文中数据属性列表*/static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {[UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },[UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },[UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },[UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },[UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },[UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },[UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },};/*** 把libubus关注的无序报文转化为有序的blob_attr数组*/__hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)/*** 发送报文** @param ctx    - client上下文对象* @param seq    - 报文顺序号 hdr.seq* @param msg    - 报文内容* @param cmd    - 报文类型 hdr.type* @param perr   -* @param fd     - 需传递给对端的描述符，等于-1表示不需传递*/int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,struct blob_attr *msg, int cmd, uint32_t peer, int fd)/*** client端fd收包处理函数*/void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)/*** client端轮询fd收包处理函数*/void __hidden ubus_poll_data(struct ubus_context *ctx, int timeout)/*** client连接ubusd server*/int ubus_reconnect(struct ubus_context *ctx, const char *path)

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libubus-obj 
数据结构 

struct ubus_object {struct avl_node avl;  /** 关系到struct ubus_context的objects */const char *name;     /** UBUS_ATTR_OBJPATH */uint32_t id;          /** 由ubusd server分配的obj id */const char *path;struct ubus_object_type *type;/** 第1次被订阅或最后1次补退订时被调用 */ubus_state_handler_t subscribe_cb;bool has_subscribers;    /** 此对象是否被订阅 */const struct ubus_method *methods;  /** 方法数组 */int n_methods;                      /** 方法数组个数 */};struct ubus_object_type {const char *name;uint32_t id;            /** 由ubusd server分配的obj type id */const struct ubus_method *methods;  /** 方法数组 */int n_methods;                      /** 方法数组个数 */};struct ubus_method {const char *name;         /** 方法名称 */ubus_handler_t handler;   /** 方法处理回调函数 */unsigned long mask;                   /** 参数过滤掩码 */const struct blobmsg_policy *policy;  /** 参数过滤列表 */int n_policy;                         /** 参数过滤列表个数 */};

接口说明 

/*** client端向ubusd server请求增加一个新object*/int ubus_add_object(struct ubus_context *ctx, struct ubus_object *obj)/*** client端向ubusd server请求删除一个object*/int ubus_remove_object(struct ubus_context *ctx, struct ubus_object *obj)/*** 处理收到与object相关报文*/void __hidden ubus_process_obj_msg(struct ubus_context *ctx,struct ubus_msghdr *hdr)/*** 处理UBUS_MSG_INVOKE报文*/static voidubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr,struct ubus_object *obj, struct blob_attr **attrbuf)/*** 处理UBUS_MSG_UNSUBSCRIBE报文*/static voidubus_process_unsubscribe(struct ubus_context *ctx, struct ubus_msghdr *hdr,struct ubus_object *obj, struct blob_attr **attrbuf)/*** 处理UBUS_MSG_NOTIFY报文*/static voidubus_process_notify(struct ubus_context *ctx, struct ubus_msghdr *hdr,struct ubus_object *obj, struct blob_attr **attrbuf)

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libubus-sub 
数据结构 

struct ubus_subscriber {struct ubus_object obj;ubus_handler_t cb;ubus_remove_handler_t remove_cb;};

接口说明 

/****/int ubus_register_subscriber(struct ubus_context *ctx, struct ubus_subscriber *s)/****/int ubus_subscribe(struct ubus_context *ctx, struct ubus_subscriber *obj,uint32_t id)/****/int ubus_unsubscribe(struct ubus_context *ctx, struct ubus_subscriber *obj,uint32_t id)

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libubus-req 
数据结构 

struct ubus_request_data {uint32_t object;uint32_t peer;uint16_t seq;/* internal use */bool deferred;int fd;};struct ubus_request {struct list_head list;struct list_head pending;int status_code;bool status_msg;bool blocked;bool cancelled;bool notify;uint32_t peer;uint16_t seq;ubus_data_handler_t raw_data_cb;ubus_data_handler_t data_cb;ubus_fd_handler_t fd_cb;ubus_complete_handler_t complete_cb;struct ubus_context *ctx;void *priv;};struct ubus_notify_request {struct ubus_request req;ubus_notify_complete_handler_t status_cb;ubus_notify_complete_handler_t complete_cb;uint32_t pending;uint32_t id[UBUS_MAX_NOTIFY_PEERS + 1];};

接口说明 

/*** 发送回应信息，消息类型UBUS_MSG_DATA*/int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,struct blob_attr *msg)/*** 异步通知指定object执行其方法*/int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,struct blob_attr *msg, struct ubus_request *req)/*** 同步通知指定object执行其方法*/int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,struct blob_attr *msg, ubus_data_handler_t cb, void *priv,int timeout)/*** 异步发出通知消息*/int ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,const char *type, struct blob_attr *msg,struct ubus_notify_request *req)/*** 同步发出通知消息*/int ubus_notify(struct ubus_context *ctx, struct ubus_object *obj,const char *type, struct blob_attr *msg, int timeout)

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例子 
向ubusd注册新object 

定义object方法:

enum {OBJ_SET_ARG1,OBJ_SET_ARG2,__OBJ_SET_ATTR_MAX};/** 定义set方法参数列表 */static const struct blobmsg_policy obj_set_attrs[__OBJ_SET_ATTR_MAX] = {[OBJ_SET_ARG1] = { .name = "arg1", .type = BLOBMSG_TYPE_STRING },[OBJ_SET_ARG2 ] = { .name = "arg2", .type = BLOBMSG_TYPE_STRING },};static struct ubus_method obj_methods[] = {{ .name = "enable", .handler = obj_enable },UBUS_METHOD("set", obj_set, obj_set_attrs),{ .name = "dump", .handler = obj_dump },};

定义object类型:

static struct ubus_object_type obj_type =UBUS_OBJECT_TYPE("my_obj", obj_methods);

定义object:

static struct ubus_object obj = {.name = "myobj",.type = &obj_type,.methods = obj_methods,.n_methods = ARRAR_SIZE(obj_methods),};

注册新object:

uloop_init();struct ubus_context *ubus_ctx = ubus_connect(NULL);ubus_add_uloop(ubus_ctx);ubus_add_object(ubus_ctx, &obj);uloop_run();

向ubusd注册事件监听 

定义事件触发回调方法:

static voidevent_receive_cb(struct ubus_context *ctx, struct ubus_event_handler *ev,const char *type, struct blob_attr *msg){enum {EV_ACTION,EV_IFNAME,__EV_MAX};static const struct blobmsg_policy ev_policy[__EV_MAX] = {[EV_ACTION] = { .name = "action", .type = BLOBMSG_TYPE_STRING },[EV_IFNAME] = { .name = "interface", .type = BLOBMSG_TYPE_STRING },};struct blob_attr *tb[__EV_MAX];blobmsg_parse(ev_policy, __EV_MAX, tb, blob_data(msg), blob_len(msg));/* do something */}

注册监听事件

static voidevent_listen(void){static struct ubus_event_handler listener;memset(&listener, 0, sizeof(listener));/** 监听netwrok.interface事件 */ubus_register_event_handler(ubus_ctx, &listener, "network.interface");}

向ubusd发送命令 

定义命令返回回调方法:

static voidcommand_cb(struct ubus_request *req, int type, struct blob_attr *msg){if (!msg)return;enum {ADDR_IPV4,__ADDR_MAX,};static const struct blobmsg_policy policy[__ADDR_MAX] = {[ADDR_IPV4] = { .name = "ipv4-address", .type = BLOBMSG_TYPE_ARRAY },};struct blob_attr *tb[__ADDR_MAX];blobmsg_parse(policy, __ADDR_MAX, tb, blobmsg_data(msg), blobmsg_len(msg));/** do something */}

发送命令:

static voidinvoke_command(char *net){uint32_t id;char path[64] = {0};sprintf(path, "network.interface.%s", net);/** lookup `network.interface.%s` object id */ubus_lookup_id(ubus_ctx, path, &id);/** invoke command `status` */ubus_invoke(ubus_ctx, id, "status", NULL, command_cb, NULL, 500);}