diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c index 6b9a7d811e0f..e595fd02a5d8 100644 --- a/net/ethtool/netlink.c +++ b/net/ethtool/netlink.c @@ -173,6 +173,327 @@ err: return NULL; } +/* GET request helpers */ + +/** + * struct ethnl_dump_ctx - context structure for generic dumpit() callback + * @ops: request ops of currently processed message type + * @req_info: parsed request header of processed request + * @pos_hash: saved iteration position - hashbucket + * @pos_idx: saved iteration position - index + * + * These parameters are kept in struct netlink_callback as context preserved + * between iterations. They are initialized by ethnl_default_start() and used + * in ethnl_default_dumpit() and ethnl_default_done(). + */ +struct ethnl_dump_ctx { + const struct ethnl_request_ops *ops; + struct ethnl_req_info *req_info; + struct ethnl_reply_data *reply_data; + int pos_hash; + int pos_idx; +}; + +static const struct ethnl_request_ops * +ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = { +}; + +static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback *cb) +{ + return (struct ethnl_dump_ctx *)cb->ctx; +} + +/** + * ethnl_default_parse() - Parse request message + * @req_info: pointer to structure to put data into + * @nlhdr: pointer to request message header + * @net: request netns + * @request_ops: struct request_ops for request type + * @extack: netlink extack for error reporting + * @require_dev: fail if no device identified in header + * + * Parse universal request header and call request specific ->parse_request() + * callback (if defined) to parse the rest of the message. + * + * Return: 0 on success or negative error code + */ +static int ethnl_default_parse(struct ethnl_req_info *req_info, + const struct nlmsghdr *nlhdr, struct net *net, + const struct ethnl_request_ops *request_ops, + struct netlink_ext_ack *extack, bool require_dev) +{ + struct nlattr **tb; + int ret; + + tb = kmalloc_array(request_ops->max_attr + 1, sizeof(tb[0]), + GFP_KERNEL); + if (!tb) + return -ENOMEM; + + ret = nlmsg_parse(nlhdr, GENL_HDRLEN, tb, request_ops->max_attr, + request_ops->request_policy, extack); + if (ret < 0) + goto out; + ret = ethnl_parse_header(req_info, tb[request_ops->hdr_attr], net, + extack, require_dev); + if (ret < 0) + goto out; + + if (request_ops->parse_request) { + ret = request_ops->parse_request(req_info, tb, extack); + if (ret < 0) + goto out; + } + + ret = 0; +out: + kfree(tb); + return ret; +} + +/** + * ethnl_init_reply_data() - Initialize reply data for GET request + * @req_info: pointer to embedded struct ethnl_req_info + * @ops: instance of struct ethnl_request_ops describing the layout + * @dev: network device to initialize the reply for + * + * Fills the reply data part with zeros and sets the dev member. Must be called + * before calling the ->fill_reply() callback (for each iteration when handling + * dump requests). + */ +static void ethnl_init_reply_data(struct ethnl_reply_data *reply_data, + const struct ethnl_request_ops *ops, + struct net_device *dev) +{ + memset(reply_data, 0, ops->reply_data_size); + reply_data->dev = dev; +} + +/* default ->doit() handler for GET type requests */ +static int ethnl_default_doit(struct sk_buff *skb, struct genl_info *info) +{ + struct ethnl_reply_data *reply_data = NULL; + struct ethnl_req_info *req_info = NULL; + const u8 cmd = info->genlhdr->cmd; + const struct ethnl_request_ops *ops; + struct sk_buff *rskb; + void *reply_payload; + int reply_len; + int ret; + + ops = ethnl_default_requests[cmd]; + if (WARN_ONCE(!ops, "cmd %u has no ethnl_request_ops\n", cmd)) + return -EOPNOTSUPP; + req_info = kzalloc(ops->req_info_size, GFP_KERNEL); + if (!req_info) + return -ENOMEM; + reply_data = kmalloc(ops->reply_data_size, GFP_KERNEL); + if (!reply_data) { + kfree(req_info); + return -ENOMEM; + } + + ret = ethnl_default_parse(req_info, info->nlhdr, genl_info_net(info), ops, + info->extack, !ops->allow_nodev_do); + if (ret < 0) + goto err_dev; + ethnl_init_reply_data(reply_data, ops, req_info->dev); + + rtnl_lock(); + ret = ops->prepare_data(req_info, reply_data, info); + rtnl_unlock(); + if (ret < 0) + goto err_cleanup; + reply_len = ops->reply_size(req_info, reply_data); + if (ret < 0) + goto err_cleanup; + ret = -ENOMEM; + rskb = ethnl_reply_init(reply_len, req_info->dev, ops->reply_cmd, + ops->hdr_attr, info, &reply_payload); + if (!rskb) + goto err_cleanup; + ret = ops->fill_reply(rskb, req_info, reply_data); + if (ret < 0) + goto err_msg; + if (ops->cleanup_data) + ops->cleanup_data(reply_data); + + genlmsg_end(rskb, reply_payload); + if (req_info->dev) + dev_put(req_info->dev); + kfree(reply_data); + kfree(req_info); + return genlmsg_reply(rskb, info); + +err_msg: + WARN_ONCE(ret == -EMSGSIZE, "calculated message payload length (%d) not sufficient\n", reply_len); + nlmsg_free(rskb); +err_cleanup: + if (ops->cleanup_data) + ops->cleanup_data(reply_data); +err_dev: + if (req_info->dev) + dev_put(req_info->dev); + kfree(reply_data); + kfree(req_info); + return ret; +} + +static int ethnl_default_dump_one(struct sk_buff *skb, struct net_device *dev, + const struct ethnl_dump_ctx *ctx) +{ + int ret; + + ethnl_init_reply_data(ctx->reply_data, ctx->ops, dev); + rtnl_lock(); + ret = ctx->ops->prepare_data(ctx->req_info, ctx->reply_data, NULL); + rtnl_unlock(); + if (ret < 0) + goto out; + ret = ethnl_fill_reply_header(skb, dev, ctx->ops->hdr_attr); + if (ret < 0) + goto out; + ret = ctx->ops->fill_reply(skb, ctx->req_info, ctx->reply_data); + +out: + if (ctx->ops->cleanup_data) + ctx->ops->cleanup_data(ctx->reply_data); + ctx->reply_data->dev = NULL; + return ret; +} + +/* Default ->dumpit() handler for GET requests. Device iteration copied from + * rtnl_dump_ifinfo(); we have to be more careful about device hashtable + * persistence as we cannot guarantee to hold RTNL lock through the whole + * function as rtnetnlink does. + */ +static int ethnl_default_dumpit(struct sk_buff *skb, + struct netlink_callback *cb) +{ + struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb); + struct net *net = sock_net(skb->sk); + int s_idx = ctx->pos_idx; + int h, idx = 0; + int ret = 0; + void *ehdr; + + rtnl_lock(); + for (h = ctx->pos_hash; h < NETDEV_HASHENTRIES; h++, s_idx = 0) { + struct hlist_head *head; + struct net_device *dev; + unsigned int seq; + + head = &net->dev_index_head[h]; + +restart_chain: + seq = net->dev_base_seq; + cb->seq = seq; + idx = 0; + hlist_for_each_entry(dev, head, index_hlist) { + if (idx < s_idx) + goto cont; + dev_hold(dev); + rtnl_unlock(); + + ehdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + ðtool_genl_family, 0, + ctx->ops->reply_cmd); + if (!ehdr) { + dev_put(dev); + ret = -EMSGSIZE; + goto out; + } + ret = ethnl_default_dump_one(skb, dev, ctx); + dev_put(dev); + if (ret < 0) { + genlmsg_cancel(skb, ehdr); + if (ret == -EOPNOTSUPP) + goto lock_and_cont; + if (likely(skb->len)) + ret = skb->len; + goto out; + } + genlmsg_end(skb, ehdr); +lock_and_cont: + rtnl_lock(); + if (net->dev_base_seq != seq) { + s_idx = idx + 1; + goto restart_chain; + } +cont: + idx++; + } + + } + rtnl_unlock(); + +out: + ctx->pos_hash = h; + ctx->pos_idx = idx; + nl_dump_check_consistent(cb, nlmsg_hdr(skb)); + + return ret; +} + +/* generic ->start() handler for GET requests */ +static int ethnl_default_start(struct netlink_callback *cb) +{ + struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb); + struct ethnl_reply_data *reply_data; + const struct ethnl_request_ops *ops; + struct ethnl_req_info *req_info; + struct genlmsghdr *ghdr; + int ret; + + BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx)); + + ghdr = nlmsg_data(cb->nlh); + ops = ethnl_default_requests[ghdr->cmd]; + if (WARN_ONCE(!ops, "cmd %u has no ethnl_request_ops\n", ghdr->cmd)) + return -EOPNOTSUPP; + req_info = kzalloc(ops->req_info_size, GFP_KERNEL); + if (!req_info) + return -ENOMEM; + reply_data = kmalloc(ops->reply_data_size, GFP_KERNEL); + if (!reply_data) { + kfree(req_info); + return -ENOMEM; + } + + ret = ethnl_default_parse(req_info, cb->nlh, sock_net(cb->skb->sk), ops, + cb->extack, false); + if (req_info->dev) { + /* We ignore device specification in dump requests but as the + * same parser as for non-dump (doit) requests is used, it + * would take reference to the device if it finds one + */ + dev_put(req_info->dev); + req_info->dev = NULL; + } + if (ret < 0) + return ret; + + ctx->ops = ops; + ctx->req_info = req_info; + ctx->reply_data = reply_data; + ctx->pos_hash = 0; + ctx->pos_idx = 0; + + return 0; +} + +/* default ->done() handler for GET requests */ +static int ethnl_default_done(struct netlink_callback *cb) +{ + struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb); + + kfree(ctx->reply_data); + kfree(ctx->req_info); + + return 0; +} + /* notifications */ typedef void (*ethnl_notify_handler_t)(struct net_device *dev, unsigned int cmd, diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h index 05d7183da894..6ec0dd06277f 100644 --- a/net/ethtool/netlink.h +++ b/net/ethtool/netlink.h @@ -200,16 +200,130 @@ static inline unsigned int ethnl_reply_header_size(void) nla_total_size(IFNAMSIZ)); } +/* GET request handling */ + +/* Unified processing of GET requests uses two data structures: request info + * and reply data. Request info holds information parsed from client request + * and its stays constant through all request processing. Reply data holds data + * retrieved from ethtool_ops callbacks or other internal sources which is used + * to compose the reply. When processing a dump request, request info is filled + * only once (when the request message is parsed) but reply data is filled for + * each reply message. + * + * Both structures consist of part common for all request types (struct + * ethnl_req_info and struct ethnl_reply_data defined below) and optional + * parts specific for each request type. Common part always starts at offset 0. + */ + /** * struct ethnl_req_info - base type of request information for GET requests * @dev: network device the request is for (may be null) * @flags: request flags common for all request types * - * This is a common base, additional members may follow after this structure. + * This is a common base for request specific structures holding data from + * parsed userspace request. These always embed struct ethnl_req_info at + * zero offset. */ struct ethnl_req_info { struct net_device *dev; u32 flags; }; +/** + * struct ethnl_reply_data - base type of reply data for GET requests + * @dev: device for current reply message; in single shot requests it is + * equal to ðnl_req_info.dev; in dumps it's different for each + * reply message + * + * This is a common base for request specific structures holding data for + * kernel reply message. These always embed struct ethnl_reply_data at zero + * offset. + */ +struct ethnl_reply_data { + struct net_device *dev; +}; + +static inline int ethnl_ops_begin(struct net_device *dev) +{ + if (dev && dev->ethtool_ops->begin) + return dev->ethtool_ops->begin(dev); + else + return 0; +} + +static inline void ethnl_ops_complete(struct net_device *dev) +{ + if (dev && dev->ethtool_ops->complete) + dev->ethtool_ops->complete(dev); +} + +/** + * struct ethnl_request_ops - unified handling of GET requests + * @request_cmd: command id for request (GET) + * @reply_cmd: command id for reply (GET_REPLY) + * @hdr_attr: attribute type for request header + * @max_attr: maximum (top level) attribute type + * @req_info_size: size of request info + * @reply_data_size: size of reply data + * @request_policy: netlink policy for message contents + * @allow_nodev_do: allow non-dump request with no device identification + * @parse_request: + * Parse request except common header (struct ethnl_req_info). Common + * header is already filled on entry, the rest up to @repdata_offset + * is zero initialized. This callback should only modify type specific + * request info by parsed attributes from request message. + * @prepare_data: + * Retrieve and prepare data needed to compose a reply message. Calls to + * ethtool_ops handlers are limited to this callback. Common reply data + * (struct ethnl_reply_data) is filled on entry, type specific part after + * it is zero initialized. This callback should only modify the type + * specific part of reply data. Device identification from struct + * ethnl_reply_data is to be used as for dump requests, it iterates + * through network devices while dev member of struct ethnl_req_info + * points to the device from client request. + * @reply_size: + * Estimate reply message size. Returned value must be sufficient for + * message payload without common reply header. The callback may returned + * estimate higher than actual message size if exact calculation would + * not be worth the saved memory space. + * @fill_reply: + * Fill reply message payload (except for common header) from reply data. + * The callback must not generate more payload than previously called + * ->reply_size() estimated. + * @cleanup_data: + * Optional cleanup called when reply data is no longer needed. Can be + * used e.g. to free any additional data structures outside the main + * structure which were allocated by ->prepare_data(). When processing + * dump requests, ->cleanup() is called for each message. + * + * Description of variable parts of GET request handling when using the + * unified infrastructure. When used, a pointer to an instance of this + * structure is to be added to ðnl_default_requests array and generic + * handlers ethnl_default_doit(), ethnl_default_dumpit(), + * ethnl_default_start() and ethnl_default_done() used in @ethtool_genl_ops. + */ +struct ethnl_request_ops { + u8 request_cmd; + u8 reply_cmd; + u16 hdr_attr; + unsigned int max_attr; + unsigned int req_info_size; + unsigned int reply_data_size; + const struct nla_policy *request_policy; + bool allow_nodev_do; + + int (*parse_request)(struct ethnl_req_info *req_info, + struct nlattr **tb, + struct netlink_ext_ack *extack); + int (*prepare_data)(const struct ethnl_req_info *req_info, + struct ethnl_reply_data *reply_data, + struct genl_info *info); + int (*reply_size)(const struct ethnl_req_info *req_info, + const struct ethnl_reply_data *reply_data); + int (*fill_reply)(struct sk_buff *skb, + const struct ethnl_req_info *req_info, + const struct ethnl_reply_data *reply_data); + void (*cleanup_data)(struct ethnl_reply_data *reply_data); +}; + #endif /* _NET_ETHTOOL_NETLINK_H */