[dpdk-dev] [PATCH v2 03/10] telemetry: add client feature and sockets

[Mattias Rönnblom]

On 2018-10-03 19:36, Kevin Laatz wrote:
> From: Ciara Power <ciara.power at intel.com>
> 
> This patch introduces clients to the telemetry API.
> 
> When a client makes a connection through the initial telemetry
> socket, they can send a message through the socket to be
> parsed. Register messages are expected through this socket, to
> enable clients to register and have a client socket setup for
> future communications.
> 
> A TAILQ is used to store all clients information. Using this, the
> client sockets are polled for messages, which will later be parsed
> and dealt with accordingly.
> 
> Functionality that make use of the client sockets were introduced
> in this patch also, such as writing to client sockets, and sending
> error responses.
> 
> Signed-off-by: Ciara Power <ciara.power at intel.com>
> Signed-off-by: Brian Archbold <brian.archbold at intel.com>
> Signed-off-by: Kevin Laatz <kevin.laatz at intel.com>
> ---
>   lib/librte_telemetry/meson.build              |   2 +
>   lib/librte_telemetry/rte_telemetry.c          | 365 +++++++++++++++++++++++++-
>   lib/librte_telemetry/rte_telemetry_internal.h |  25 ++
>   mk/rte.app.mk                                 |   2 +-
>   4 files changed, 390 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/librte_telemetry/meson.build b/lib/librte_telemetry/meson.build
> index 7716076..0ccfa36 100644
> --- a/lib/librte_telemetry/meson.build
> +++ b/lib/librte_telemetry/meson.build
> @@ -5,3 +5,5 @@ sources = files('rte_telemetry.c')
>   headers = files('rte_telemetry.h', 'rte_telemetry_internal.h')
>   deps += ['metrics', 'ethdev']
>   cflags += '-DALLOW_EXPERIMENTAL_API'
> +jansson = cc.find_library('jansson', required: true)
> +ext_deps += jansson
> diff --git a/lib/librte_telemetry/rte_telemetry.c b/lib/librte_telemetry/rte_telemetry.c
> index 0c99d66..7726fd4 100644
> --- a/lib/librte_telemetry/rte_telemetry.c
> +++ b/lib/librte_telemetry/rte_telemetry.c
> @@ -7,6 +7,7 @@
>   #include <pthread.h>
>   #include <sys/socket.h>
>   #include <sys/un.h>
> +#include <jansson.h>
>   
>   #include <rte_eal.h>
>   #include <rte_ethdev.h>
> @@ -16,6 +17,8 @@
>   #include "rte_telemetry.h"
>   #include "rte_telemetry_internal.h"
>   
> +#define BUF_SIZE 1024
> +#define ACTION_POST 1
>   #define SLEEP_TIME 10
>   
>   #define DEFAULT_DPDK_PATH "/var/run/.rte_telemetry"
> @@ -34,6 +37,91 @@ rte_telemetry_is_port_active(int port_id)
>   
>   	TELEMETRY_LOG_ERR("port_id: %d is invalid, not active",
>   		port_id);
> +
> +	return 0;
> +}
> +
> +int32_t
> +rte_telemetry_write_to_socket(struct telemetry_impl *telemetry,
> +	const char *json_string)
> +{
> +	int ret;
> +
> +	if (!telemetry) {
> +		TELEMETRY_LOG_ERR("Could not initialise TELEMETRY_API");
> +		return -1;
> +	}

1.8.1 here again, and in many instances below.

> +
> +	if (!telemetry->request_client) {
> +		TELEMETRY_LOG_ERR("No client has been chosen to write to");
> +		return -1;
> +	} > +
> +	if (!json_string) {
> +		TELEMETRY_LOG_ERR("Invalid JSON string!");
> +		return -1;
> +	}
> +
> +	ret = send(telemetry->request_client->fd,
> +			json_string, strlen(json_string), 0);

How would this code handle a partial success (as in, for example, half 
of the string fits the socket buffer)? In not, maybe switching over to a 
SOCK_SEQPACKET AF_UNIX socket would be the best way around it.

> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Failed to write to socket for client: %s",
> +				telemetry->request_client->file_path);
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +int32_t
> +rte_telemetry_send_error_response(struct telemetry_impl *telemetry,
> +	int error_type)
> +{
> +	int ret;
> +	const char *status_code, *json_buffer;
> +	json_t *root;
> +
> +	if (error_type == -EPERM)
> +		status_code = "Status Error: Unknown";
> +	else if (error_type == -EINVAL)
> +		status_code = "Status Error: Invalid Argument 404";
> +	else if (error_type == -ENOMEM)
> +		status_code = "Status Error: Memory Allocation Error";
> +	else {
> +		TELEMETRY_LOG_ERR("Invalid error type");
> +		return -EINVAL;
> +	}
> +
> +	root = json_object();
> +
> +	if (!root) {
> +		TELEMETRY_LOG_ERR("Could not create root JSON object");
> +		return -EPERM;
> +	}
> +
> +	ret = json_object_set_new(root, "status_code",
> +		json_string(status_code));
> +
> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Status code field cannot be set");

No json_decref()?

> +		return -EPERM;
> +	}
> +
> +	ret = json_object_set_new(root, "data", json_null());
> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Data field cannot be set");

... and a json_decref() here too?

> +		return -EPERM;
> +	}
> +
> +	json_buffer = json_dumps(root, JSON_INDENT(2));
> +	json_decref(root);
> +
> +	ret = rte_telemetry_write_to_socket(telemetry, json_buffer);
> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Could not write to socket");
> +		return -EPERM;
> +	}
> +
>   	return 0;
>   }
>   
> @@ -110,8 +198,7 @@ rte_telemetry_initial_accept(struct telemetry_impl *telemetry)
>   	int pid;
>   
>   	RTE_ETH_FOREACH_DEV(pid) {
> -		telemetry->reg_index =
> -			rte_telemetry_reg_ethdev_to_metrics(pid);
> +		telemetry->reg_index = rte_telemetry_reg_ethdev_to_metrics(pid);
>   		break;
>   	}
>   
> @@ -126,6 +213,33 @@ rte_telemetry_initial_accept(struct telemetry_impl *telemetry)
>   }
>   
>   static int32_t
> +rte_telemetry_read_client(struct telemetry_impl *telemetry)
> +{
> +	char buf[BUF_SIZE];
> +	int ret, buffer_read = 0;
> +	errno = 0;

Generally speaking, you don't touch errno unless your function fails. In 
this case, I don't see the point at all.

> +
> +	buffer_read = read(telemetry->accept_fd, buf, BUF_SIZE-1);

This and the below code seem to assume that read() returns one and only 
one message, but on a SOCK_STREAM, there is no such thing as a message. 
It's a byte stream, and you need to provide your own framing, or have an 
application protocol which allows only have one outstanding request. If 
you do the latter, you still need to allow for "short" (partial) read()s 
(i.e. re-read() until done).

> +	buf[buffer_read] = '\0';

If buffer_read == -1, the above isn't a good idea.

> +
> +	if (buffer_read == -1) {
> +		TELEMETRY_LOG_ERR("Read error");
> +		return -1;
> +	} else if (buffer_read == 0) {
> +		close(telemetry->accept_fd);
> +		telemetry->accept_fd = 0;
> +	} else {
> +		ret = rte_telemetry_parse_client_message(telemetry, buf);
> +		if (ret < 0)
> +			TELEMETRY_LOG_WARN("Parse message failed");
> +		close(telemetry->accept_fd);
> +		telemetry->accept_fd = 0;

Maybe put the cleanup actions behind a goto label?

> +	}
> +
> +	return 0;
> +}
> +
> +static int32_t
>   rte_telemetry_accept_new_client(struct telemetry_impl *telemetry)
>   {
>   	int ret;
> @@ -136,8 +250,8 @@ rte_telemetry_accept_new_client(struct telemetry_impl *telemetry)
>   			TELEMETRY_LOG_ERR("Listening error with server fd");
>   			return -1;
>   		}
> -		telemetry->accept_fd = accept(telemetry->server_fd, NULL, NULL);
>   
> +		telemetry->accept_fd = accept(telemetry->server_fd, NULL, NULL);
>   		if (telemetry->accept_fd > 0 &&
>   			telemetry->metrics_register_done == 0) {
>   			ret = rte_telemetry_initial_accept(telemetry);
> @@ -146,6 +260,31 @@ rte_telemetry_accept_new_client(struct telemetry_impl *telemetry)
>   				return -1;
>   			}
>   		}
> +	} else {
> +		ret = rte_telemetry_read_client(telemetry);
> +		if (ret < 0) {
> +			TELEMETRY_LOG_ERR("Failed to read socket buffer");
> +			return -1;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int32_t
> +rte_telemetry_read_client_sockets(struct telemetry_impl *telemetry)
> +{
> +	telemetry_client *client;
> +	char client_buf[BUF_SIZE];
> +	int bytes;
> +
> +	TAILQ_FOREACH(client, &telemetry->client_list_head, client_list) {
> +		bytes = read(client->fd, client_buf, BUF_SIZE-1);
> +		client_buf[bytes] = '\0';
> +
> +		if (bytes > 0) {
> +			telemetry->request_client = client;
> +		}
>   	}
>   
>   	return 0;
> @@ -168,6 +307,12 @@ rte_telemetry_run(void *userdata)
>   		return -1;
>   	}
>   
> +	ret = rte_telemetry_read_client_sockets(telemetry);
> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Client socket read failed");
> +		return -1;
> +	}
> +
>   	return 0;
>   }
>   
> @@ -268,6 +413,7 @@ rte_telemetry_init()
>   			TELEMETRY_LOG_ERR("TELEMETRY cleanup failed");
>   		return -EPERM;
>   	}
> +	TAILQ_INIT(&static_telemetry->client_list_head);
>   
>   	pthread_attr_init(&attr);
>   	ret = rte_ctrl_thread_create(&static_telemetry->thread_id,
> @@ -285,11 +431,39 @@ rte_telemetry_init()
>   	return 0;
>   }
>   
> +static int32_t
> +rte_telemetry_client_cleanup(struct telemetry_client *client)
> +{
> +	int ret;
> +
> +	ret = close(client->fd);
> +	free(client->file_path);
> +	free(client);
> +
> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Close client socket failed");
> +		return -EPERM;

There are other close() calls for which the return code is not checked. 
The code should be consistent, one way or the other.

> +	}
> +
> +	return 0;
> +}
> +
>   int32_t
>   rte_telemetry_cleanup(void)
>   {
>   	int ret;
>   	struct telemetry_impl *telemetry = static_telemetry;
> +	telemetry_client *client, *temp_client;
> +
> +	TAILQ_FOREACH_SAFE(client, &telemetry->client_list_head, client_list,
> +		temp_client) {
> +		TAILQ_REMOVE(&telemetry->client_list_head, client, client_list);
> +		ret = rte_telemetry_client_cleanup(client);
> +		if (ret < 0) {
> +			TELEMETRY_LOG_ERR("Client cleanup failed");
> +			return -EPERM;
> +		}
> +	}
>   
>   	ret = close(telemetry->server_fd);
>   	if (ret < 0) {
> @@ -306,6 +480,191 @@ rte_telemetry_cleanup(void)
>   	return 0;
>   }
>   
> +int32_t
> +rte_telemetry_unregister_client(struct telemetry_impl *telemetry,
> +	const char *client_path)
> +{
> +	int ret;
> +	telemetry_client *client, *temp_client;
> +
> +	if (!telemetry) {
> +		TELEMETRY_LOG_WARN("TELEMETRY is not initialised");
> +		return -ENODEV;
> +	}
> +
> +	if (!client_path) {
> +		TELEMETRY_LOG_ERR("Invalid client path");
> +		goto einval_fail;
> +	}
> +
> +	if (TAILQ_EMPTY(&telemetry->client_list_head)) {
> +		TELEMETRY_LOG_ERR("There are no clients currently registered");
> +		return -EPERM;
> +	}
> +
> +	TAILQ_FOREACH_SAFE(client, &telemetry->client_list_head, client_list,
> +			temp_client) {
> +		if (strcmp(client_path, client->file_path) == 0) {
> +			TAILQ_REMOVE(&telemetry->client_list_head, client,
> +				client_list);
> +			ret = rte_telemetry_client_cleanup(client);
> +
> +			if (ret < 0) {
> +				TELEMETRY_LOG_ERR("Client cleanup failed");
> +				return -EPERM;
> +			}
> +
> +			return 0;
> +		}
> +	}
> +
> +	TELEMETRY_LOG_WARN("Couldn't find client, possibly not registered yet.");
> +	return -1;
> +
> +einval_fail:
> +	ret = rte_telemetry_send_error_response(telemetry, -EINVAL);
> +	if (ret < 0)
> +		TELEMETRY_LOG_ERR("Could not send error");
> +	return -EINVAL;
> +}
> +
> +int32_t
> +rte_telemetry_register_client(struct telemetry_impl *telemetry,
> +	const char *client_path)
> +{
> +	int ret, fd;
> +	struct sockaddr_un addrs = {0};

Setting all the fields, so no need to clear the struct.

> +
> +	if (!telemetry) {
> +		TELEMETRY_LOG_ERR("Could not initialize TELEMETRY API");
> +		return -ENODEV;
> +	}
> +
> +	if (!client_path) {
> +		TELEMETRY_LOG_ERR("Invalid client path");
> +		return -EINVAL;
> +	}
> +
> +	telemetry_client *client;
> +	TAILQ_FOREACH(client, &telemetry->client_list_head, client_list) {
> +		if (strcmp(client_path, client->file_path) == 0) {
> +			TELEMETRY_LOG_WARN("'%s' already registered",
> +					client_path);
> +			return -EINVAL;
> +		}
> +	}
> +	fd = socket(AF_UNIX, SOCK_STREAM, 0);
> +	if (fd == -1) {
> +		TELEMETRY_LOG_ERR("Client socket error");
> +		return -EACCES;
> +	}
> +	ret = rte_telemetry_set_socket_nonblock(fd);

You could also use SOCK_NONBLOCK at the time of the socket() call.

> +	if (ret < 0) {
> +		TELEMETRY_LOG_ERR("Could not set socket to NONBLOCK");
> +		return -EPERM;
> +	}
> +
> +	addrs.sun_family = AF_UNIX;
> +	strlcpy(addrs.sun_path, client_path, sizeof(addrs.sun_path));
> +	telemetry_client *new_client =
> +		(telemetry_client *)malloc(sizeof(telemetry_client));

malloc() returns a void pointer, so no need to cast.