ubusd_proto.c

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/*
 * Copyright (C) 2011-2014 Felix Fietkau <nbd@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
 
#include <arpa/inet.h>
#include <unistd.h>
 
#include "ubusd.h"
 
struct blob_buf b;
static struct avl_tree clients;
 
static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
 
typedef int (*ubus_cmd_cb)(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr);
 
static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
        [UBUS_ATTR_SIGNATURE] = { .type = BLOB_ATTR_NESTED },
        [UBUS_ATTR_OBJTYPE] = { .type = BLOB_ATTR_INT32 },
        [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
        [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
        [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
        [UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
        [UBUS_ATTR_USER] = { .type = BLOB_ATTR_STRING },
        [UBUS_ATTR_GROUP] = { .type = BLOB_ATTR_STRING },
};
 
struct blob_attr **ubus_parse_msg(struct blob_attr *msg, size_t len)
{
        blob_parse_untrusted(msg, len, attrbuf, ubus_policy, UBUS_ATTR_MAX);
        return attrbuf;
}
 
static void ubus_msg_close_fd(struct ubus_msg_buf *ub)
{
        if (ub->fd < 0)
                return;
 
        close(ub->fd);
        ub->fd = -1;
}
 
static void ubus_msg_init(struct ubus_msg_buf *ub, uint8_t type, uint16_t seq, uint32_t peer)
{
        ub->hdr.version = 0;
        ub->hdr.type = type;
        ub->hdr.seq = seq;
        ub->hdr.peer = peer;
}
 
static struct ubus_msg_buf *ubus_msg_from_blob(bool shared)
{
        return ubus_msg_new(b.head, blob_raw_len(b.head), shared);
}
 
static struct ubus_msg_buf *ubus_reply_from_blob(struct ubus_msg_buf *ub, bool shared)
{
        struct ubus_msg_buf *new;
 
        new = ubus_msg_from_blob(shared);
        if (!new)
                return NULL;
 
        ubus_msg_init(new, UBUS_MSG_DATA, ub->hdr.seq, ub->hdr.peer);
        return new;
}
 
void
ubus_proto_send_msg_from_blob(struct ubus_client *cl, struct ubus_msg_buf *ub,
                        uint8_t type)
{
        /* keep the fd to be passed if it is UBUS_MSG_INVOKE */
        int fd = ub->fd;
        ub = ubus_reply_from_blob(ub, true);
        if (!ub)
                return;
 
        ub->hdr.type = type;
        ub->fd = fd;
 
        ubus_msg_send(cl, ub);
        ubus_msg_free(ub);
}
 
static bool ubusd_send_hello(struct ubus_client *cl)
{
        struct ubus_msg_buf *ub;
 
        blob_buf_init(&b, 0);
        ub = ubus_msg_from_blob(true);
        if (!ub)
                return false;
 
        ubus_msg_init(ub, UBUS_MSG_HELLO, 0, cl->id.id);
        ubus_msg_send(cl, ub);
        ubus_msg_free(ub);
        return true;
}
 
static int ubusd_send_pong(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        ub->hdr.type = UBUS_MSG_DATA;
        ubus_msg_send(cl, ub);
        return 0;
}
 
static int ubusd_handle_remove_object(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj;
 
        if (!attr[UBUS_ATTR_OBJID])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        obj = ubusd_find_object(blob_get_u32(attr[UBUS_ATTR_OBJID]));
        if (!obj)
                return UBUS_STATUS_NOT_FOUND;
 
        if (obj->client != cl)
                return UBUS_STATUS_PERMISSION_DENIED;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id.id);
 
        /* check if we're removing the object type as well */
        if (obj->type && obj->type->refcount == 1)
                blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id.id);
 
        ubus_proto_send_msg_from_blob(cl, ub, UBUS_MSG_DATA);
        ubusd_free_object(obj);
 
        return 0;
}
 
static int ubusd_handle_add_object(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj;
 
        obj = ubusd_create_object(cl, attr);
        if (!obj)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id.id);
        if (attr[UBUS_ATTR_SIGNATURE] && obj->type)
                blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id.id);
 
        ubus_proto_send_msg_from_blob(cl, ub, UBUS_MSG_DATA);
        return 0;
}
 
static void ubusd_send_obj(struct ubus_client *cl, struct ubus_msg_buf *ub, struct ubus_object *obj)
{
        struct ubus_method *m;
        int all_cnt = 0, cnt = 0;
        void *s;
 
        if (!obj->type)
                return;
 
        blob_buf_init(&b, 0);
 
        blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->path.key);
        blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id.id);
        blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id.id);
 
        s = blob_nest_start(&b, UBUS_ATTR_SIGNATURE);
        list_for_each_entry(m, &obj->type->methods, list) {
                all_cnt++;
                if (!ubusd_acl_check(cl, obj->path.key, blobmsg_name(m->data), UBUS_ACL_ACCESS)) {
                        blobmsg_add_blob(&b, m->data);
                        cnt++;
                }
        }
        blob_nest_end(&b, s);
 
        if (cnt || !all_cnt)
                ubus_proto_send_msg_from_blob(cl, ub, UBUS_MSG_DATA);
}
 
static int ubus_client_cmd_queue_add(struct ubus_client *cl,
                                        struct ubus_msg_buf *msg,
                                        struct ubus_object *obj)
{
        struct ubus_client_cmd *cmd = malloc(sizeof(*cmd));
 
        if (cmd) {
                cmd->msg = msg;
                cmd->obj = obj;
                list_add_tail(&cmd->list, &cl->cmd_queue);
                return -2;
        }
        return UBUS_STATUS_UNKNOWN_ERROR;
}
 
static int __ubusd_handle_lookup(struct ubus_client *cl,
                                struct ubus_msg_buf *ub,
                                struct blob_attr **attr,
                                struct ubus_client_cmd *cmd)
{
        struct ubus_object *obj = NULL;
        char *objpath;
        bool found = false;
        int len;
 
        if (!attr[UBUS_ATTR_OBJPATH]) {
                if (cmd)
                        obj = cmd->obj;
 
                /* Start from beginning or continue from the last object */
                if (obj == NULL)
                        obj = avl_first_element(&path, obj, path);
 
                avl_for_element_range(obj, avl_last_element(&path, obj, path), obj, path) {
                        /* Keep sending objects until buffering starts */
                        if (list_empty(&cl->tx_queue)) {
                                ubusd_send_obj(cl, ub, obj);
                        } else {
                                /* Queue command and continue on the next call */
                                int ret;
 
                                if (cmd == NULL) {
                                        ret = ubus_client_cmd_queue_add(cl, ub, obj);
                                } else {
                                        cmd->obj = obj;
                                        ret = -2;
                                }
                                return ret;
                        }
                }
                return 0;
        }
 
        objpath = blob_data(attr[UBUS_ATTR_OBJPATH]);
        len = strlen(objpath);
        if (objpath[len - 1] != '*') {
                obj = avl_find_element(&path, objpath, obj, path);
                if (!obj)
                        return UBUS_STATUS_NOT_FOUND;
 
                ubusd_send_obj(cl, ub, obj);
                return 0;
        }
 
        objpath[--len] = 0;
 
        obj = avl_find_ge_element(&path, objpath, obj, path);
        if (!obj)
                return UBUS_STATUS_NOT_FOUND;
 
        while (!strncmp(objpath, obj->path.key, len)) {
                found = true;
                ubusd_send_obj(cl, ub, obj);
                if (obj == avl_last_element(&path, obj, path))
                        break;
                obj = avl_next_element(obj, path);
        }
 
        if (!found)
                return UBUS_STATUS_NOT_FOUND;
 
        return 0;
}
 
static int ubusd_handle_lookup(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        int rc;
 
        if (list_empty(&cl->tx_queue))
                rc = __ubusd_handle_lookup(cl, ub, attr, NULL);
        else
                rc = ubus_client_cmd_queue_add(cl, ub, NULL);
 
        return rc;
}
 
int ubusd_cmd_lookup(struct ubus_client *cl, struct ubus_client_cmd *cmd)
{
        struct ubus_msg_buf *ub = cmd->msg;
        struct blob_attr **attr;
        int ret;
 
        attr = ubus_parse_msg(ub->data, blob_raw_len(ub->data));
        ret = __ubusd_handle_lookup(cl, ub, attr, cmd);
 
        if (ret != -2) {
                struct ubus_msg_buf *retmsg = cl->retmsg;
                int *retmsg_data = blob_data(blob_data(retmsg->data));
 
                retmsg->hdr.seq = ub->hdr.seq;
                retmsg->hdr.peer = ub->hdr.peer;
 
                *retmsg_data = htonl(ret);
                ubus_msg_send(cl, retmsg);
        }
        return ret;
}
 
static void
ubusd_forward_invoke(struct ubus_client *cl, struct ubus_object *obj,
                     const char *method, struct ubus_msg_buf *ub,
                     struct blob_attr *data)
{
        blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id.id);
        blob_put_string(&b, UBUS_ATTR_METHOD, method);
        if (cl->user)
                blob_put_string(&b, UBUS_ATTR_USER, cl->user);
        if (cl->group)
                blob_put_string(&b, UBUS_ATTR_GROUP, cl->group);
        if (data)
                blob_put(&b, UBUS_ATTR_DATA, blob_data(data), blob_len(data));
 
        ubus_proto_send_msg_from_blob(obj->client, ub, UBUS_MSG_INVOKE);
}
 
static int ubusd_handle_invoke(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj = NULL;
        struct ubus_id *id;
        const char *method;
 
        if (!attr[UBUS_ATTR_METHOD] || !attr[UBUS_ATTR_OBJID])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        id = ubus_find_id(&objects, blob_get_u32(attr[UBUS_ATTR_OBJID]));
        if (!id)
                return UBUS_STATUS_NOT_FOUND;
 
        obj = container_of(id, struct ubus_object, id);
 
        method = blob_data(attr[UBUS_ATTR_METHOD]);
 
        if (ubusd_acl_check(cl, obj->path.key, method, UBUS_ACL_ACCESS))
                return UBUS_STATUS_PERMISSION_DENIED;
 
        if (!obj->client)
                return obj->recv_msg(cl, ub, method, attr[UBUS_ATTR_DATA]);
 
        ub->hdr.peer = cl->id.id;
        blob_buf_init(&b, 0);
 
        ubusd_forward_invoke(cl, obj, method, ub, attr[UBUS_ATTR_DATA]);
 
        return -1;
}
 
static int ubusd_handle_notify(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj = NULL;
        struct ubus_subscription *s;
        struct ubus_id *id;
        const char *method;
        bool no_reply = false;
        void *c;
 
        if (!attr[UBUS_ATTR_METHOD] || !attr[UBUS_ATTR_OBJID])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        if (attr[UBUS_ATTR_NO_REPLY])
                no_reply = blob_get_int8(attr[UBUS_ATTR_NO_REPLY]);
 
        id = ubus_find_id(&objects, blob_get_u32(attr[UBUS_ATTR_OBJID]));
        if (!id)
                return UBUS_STATUS_NOT_FOUND;
 
        obj = container_of(id, struct ubus_object, id);
        if (obj->client != cl)
                return UBUS_STATUS_PERMISSION_DENIED;
 
        if (!no_reply) {
                blob_buf_init(&b, 0);
                blob_put_int32(&b, UBUS_ATTR_OBJID, id->id);
                c = blob_nest_start(&b, UBUS_ATTR_SUBSCRIBERS);
                list_for_each_entry(s, &obj->subscribers, list) {
                        blob_put_int32(&b, 0, s->subscriber->id.id);
                }
                blob_nest_end(&b, c);
                blob_put_int32(&b, UBUS_ATTR_STATUS, 0);
                ubus_proto_send_msg_from_blob(cl, ub, UBUS_MSG_STATUS);
        }
 
        ub->hdr.peer = cl->id.id;
        method = blob_data(attr[UBUS_ATTR_METHOD]);
        list_for_each_entry(s, &obj->subscribers, list) {
                blob_buf_init(&b, 0);
                if (no_reply)
                        blob_put_int8(&b, UBUS_ATTR_NO_REPLY, 1);
                ubusd_forward_invoke(cl, s->subscriber, method, ub, attr[UBUS_ATTR_DATA]);
        }
 
        return -1;
}
 
static struct ubus_client *ubusd_get_client_by_id(uint32_t id)
{
        struct ubus_id *clid;
 
        clid = ubus_find_id(&clients, id);
        if (!clid)
                return NULL;
 
        return container_of(clid, struct ubus_client, id);
}
 
static int ubusd_handle_response(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj;
 
        if (!attr[UBUS_ATTR_OBJID] ||
            (ub->hdr.type == UBUS_MSG_STATUS && !attr[UBUS_ATTR_STATUS]) ||
            (ub->hdr.type == UBUS_MSG_DATA && !attr[UBUS_ATTR_DATA]))
                goto out;
 
        obj = ubusd_find_object(blob_get_u32(attr[UBUS_ATTR_OBJID]));
        if (!obj)
                goto out;
 
        if (cl != obj->client)
                goto out;
 
        cl = ubusd_get_client_by_id(ub->hdr.peer);
        if (!cl)
                goto out;
 
        ub->hdr.peer = blob_get_u32(attr[UBUS_ATTR_OBJID]);
        ubus_msg_send(cl, ub);
out:
        return -1;
}
 
static int ubusd_handle_add_watch(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj, *target;
 
        if (!attr[UBUS_ATTR_OBJID] || !attr[UBUS_ATTR_TARGET])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        obj = ubusd_find_object(blob_get_u32(attr[UBUS_ATTR_OBJID]));
        if (!obj)
                return UBUS_STATUS_NOT_FOUND;
 
        if (cl != obj->client)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        target = ubusd_find_object(blob_get_u32(attr[UBUS_ATTR_TARGET]));
        if (!target || !target->client)
                return UBUS_STATUS_NOT_FOUND;
 
        if (cl == target->client)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        if (!target->path.key) {
                if (strcmp(target->client->user, cl->user) && strcmp(target->client->group, cl->group))
                        return UBUS_STATUS_NOT_FOUND;
        } else if (ubusd_acl_check(cl, target->path.key, NULL, UBUS_ACL_SUBSCRIBE)) {
                return UBUS_STATUS_NOT_FOUND;
        }
 
        ubus_subscribe(obj, target);
        return 0;
}
 
static int ubusd_handle_remove_watch(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
{
        struct ubus_object *obj;
        struct ubus_subscription *s;
        uint32_t id;
 
        if (!attr[UBUS_ATTR_OBJID] || !attr[UBUS_ATTR_TARGET])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        obj = ubusd_find_object(blob_get_u32(attr[UBUS_ATTR_OBJID]));
        if (!obj)
                return UBUS_STATUS_NOT_FOUND;
 
        if (cl != obj->client)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        id = blob_get_u32(attr[UBUS_ATTR_TARGET]);
        list_for_each_entry(s, &obj->target_list, target_list) {
                if (s->target->id.id != id)
                        continue;
 
                ubus_unsubscribe(s);
                return 0;
        }
 
        return UBUS_STATUS_NOT_FOUND;
}
 
static const ubus_cmd_cb handlers[__UBUS_MSG_LAST] = {
        [UBUS_MSG_PING] = ubusd_send_pong,
        [UBUS_MSG_ADD_OBJECT] = ubusd_handle_add_object,
        [UBUS_MSG_REMOVE_OBJECT] = ubusd_handle_remove_object,
        [UBUS_MSG_LOOKUP] = ubusd_handle_lookup,
        [UBUS_MSG_INVOKE] = ubusd_handle_invoke,
        [UBUS_MSG_STATUS] = ubusd_handle_response,
        [UBUS_MSG_DATA] = ubusd_handle_response,
        [UBUS_MSG_SUBSCRIBE] = ubusd_handle_add_watch,
        [UBUS_MSG_UNSUBSCRIBE] = ubusd_handle_remove_watch,
        [UBUS_MSG_NOTIFY] = ubusd_handle_notify,
};
 
void ubusd_proto_receive_message(struct ubus_client *cl, struct ubus_msg_buf *ub)
{
        ubus_cmd_cb cb = NULL;
        int ret;
        struct ubus_msg_buf *retmsg = cl->retmsg;
        int *retmsg_data = blob_data(blob_data(retmsg->data));
 
        retmsg->hdr.seq = ub->hdr.seq;
        retmsg->hdr.peer = ub->hdr.peer;
 
        if (ub->hdr.type < __UBUS_MSG_LAST)
                cb = handlers[ub->hdr.type];
 
        if (ub->hdr.type != UBUS_MSG_STATUS && ub->hdr.type != UBUS_MSG_INVOKE)
                ubus_msg_close_fd(ub);
 
        /* Note: no callback should free the `ub` buffer
                 that's always done right after the callback finishes */
        if (cb)
                ret = cb(cl, ub, ubus_parse_msg(ub->data, blob_raw_len(ub->data)));
        else
                ret = UBUS_STATUS_INVALID_COMMAND;
 
        /* Command has not been completed yet and got queued */
        if (ret == -2)
                return;
 
        ubus_msg_free(ub);
 
        if (ret == -1)
                return;
 
        *retmsg_data = htonl(ret);
        ubus_msg_send(cl, retmsg);
}
 
static int ubusd_proto_init_retmsg(struct ubus_client *cl)
{
        struct blob_buf *b = &cl->b;
 
        blob_buf_init(&cl->b, 0);
        blob_put_int32(&cl->b, UBUS_ATTR_STATUS, 0);
 
        /* we make the 'retmsg' buffer shared with the blob_buf b, to reduce mem duplication */
        cl->retmsg = ubus_msg_new(b->head, blob_raw_len(b->head), true);
        if (!cl->retmsg)
                return -1;
 
        cl->retmsg->hdr.type = UBUS_MSG_STATUS;
        return 0;
}
 
struct ubus_client *ubusd_proto_new_client(int fd, uloop_fd_handler cb)
{
        struct ubus_client *cl;
 
        cl = calloc(1, sizeof(*cl));
        if (!cl)
                return NULL;
 
        if (ubusd_acl_init_client(cl, fd))
                goto free;
 
        INIT_LIST_HEAD(&cl->objects);
        INIT_LIST_HEAD(&cl->cmd_queue);
        INIT_LIST_HEAD(&cl->tx_queue);
        cl->sock.fd = fd;
        cl->sock.cb = cb;
        cl->pending_msg_fd = -1;
 
        if (!ubus_alloc_id(&clients, &cl->id, 0))
                goto free;
 
        if (ubusd_proto_init_retmsg(cl))
                goto free;
 
        if (!ubusd_send_hello(cl))
                goto delete;
 
        return cl;
 
delete:
        ubus_free_id(&clients, &cl->id);
free:
        free(cl);
        return NULL;
}
 
void ubusd_proto_free_client(struct ubus_client *cl)
{
        struct ubus_object *obj, *tmp;
 
        list_for_each_entry_safe(obj, tmp, &cl->objects, list) {
                ubusd_free_object(obj);
        }
 
        ubus_msg_free(cl->retmsg);
        blob_buf_free(&cl->b);
 
        ubusd_acl_free_client(cl);
        ubus_free_id(&clients, &cl->id);
}
 
void ubus_notify_subscription(struct ubus_object *obj)
{
        bool active = !list_empty(&obj->subscribers);
        struct ubus_msg_buf *ub;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id.id);
        blob_put_int8(&b, UBUS_ATTR_ACTIVE, active);
 
        ub = ubus_msg_from_blob(false);
        if (!ub)
                return;
 
        ubus_msg_init(ub, UBUS_MSG_NOTIFY, ++obj->invoke_seq, 0);
        ubus_msg_send(obj->client, ub);
        ubus_msg_free(ub);
}
 
void ubus_notify_unsubscribe(struct ubus_subscription *s)
{
        struct ubus_msg_buf *ub;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, s->subscriber->id.id);
        blob_put_int32(&b, UBUS_ATTR_TARGET, s->target->id.id);
 
        ub = ubus_msg_from_blob(false);
        if (ub != NULL) {
                ubus_msg_init(ub, UBUS_MSG_UNSUBSCRIBE, ++s->subscriber->invoke_seq, 0);
                ubus_msg_send(s->subscriber->client, ub);
                ubus_msg_free(ub);
        }
 
        ubus_unsubscribe(s);
}
 
static void __constructor ubusd_proto_init(void)
{
        ubus_init_id_tree(&clients);
}