Connection

Detailed Description

Connection object holds information about TCP and UDP connections. There is a connection object for each of the following:

• UDP listener
• TCP listener
• TCP connection.

TCP (established) connections are tracked in a Least Recently Used cache. LRU cache is used to check for various timeout conditions. Each TCP connection has a unique Id (connection ID) associated with it. The only purpose of this ID is to provide a unique key for LRU cache. LRU cache implementation uses UT HASH.

Listener connections are not tracked in LRU cache.

UDP listener and TCP connection objects have DNS query objects associated with them.

Data Structures
struct	conn_tcp_s
struct	conn_udp_s
struct	conn_s
struct	conn_fifo_queue_s

Macros
#define	CONN_IS_UDP_LISTENER(conn)    conn->lc == 0 && conn->proto == 0
#define	CONN_IS_TCP_LISTENER(conn)    conn->lc == 0 && conn->proto == 1
#define	CONN_IS_TCP_CONN(conn)    conn->lc == 1 && conn->proto == 1

Typedefs
typedef enum listener_start_error_e	listener_start_error_t
typedef enum conn_tcp_state_e	conn_tcp_state_t
typedef struct conn_tcp_s	conn_tcp_t
typedef struct conn_udp_s	conn_udp_t
typedef struct conn_s	conn_t
typedef struct conn_fifo_queue_s	conn_fifo_queue_t

Enumerations
enum	listener_start_error_e {   LISTENER_ERR_SOCKET = -1 , LISTENER_ERR_SOCKET_OPT_REUSEADDR = -2 , LISTENER_ERR_SOCKET_OPT_REUSEPORT = -3 , LISTENER_ERR_BIND = -4 ,   LISTENER_ERR_LISTEN = -5 , LISTENER_ERR_SOCKET_OPT_IP_PKTINFO = -6 , LISTENER_ERR_SOCKET_OPT_IPV6_V6ONLY = -7 , LISTENER_ERR_SOCKET_OPT_IPV6_RECVPKTINFO = -8 ,   LISTENER_ERR_SOCKET_OPT_RCVBUF = -9 , LISTENER_ERR_SOCKET_OPT_SNDBUF = -10 }
enum	conn_tcp_state_e {   TCP_CONN_ST_ASSIGN_CONN_ID_ERR = 0 , TCP_CONN_ST_WAIT_FOR_QUERY , TCP_CONN_ST_WAIT_FOR_QUERY_DATA , TCP_CONN_ST_WAIT_FOR_WRITE ,   TCP_CONN_ST_CLOSED_FOR_READ , TCP_CONN_ST_READ_ERR , TCP_CONN_ST_CLOSED_FOR_WRITE , TCP_CONN_ST_WRITE_ERR ,   TCP_CONN_ST_QUERY_SIZE_TOOLARGE }

Functions
void	conn_fifo_enqueue_read (conn_fifo_queue_t *queue, conn_t *entry)
conn_t *	conn_fifo_dequeue_read (conn_fifo_queue_t *queue)
void	conn_fifo_enqueue_write (conn_fifo_queue_t *queue, conn_t *entry)
conn_t *	conn_fifo_dequeue_write (conn_fifo_queue_t *queue)
void	conn_fifo_enqueue_gen (conn_fifo_queue_t *queue, conn_t *conn)
conn_t *	conn_fifo_dequeue_gen (conn_fifo_queue_t *queue)
void	conn_fifo_remove_from_read_queue (conn_fifo_queue_t *queue, conn_t *conn_rm)
void	conn_fifo_remove_from_write_queue (conn_fifo_queue_t *queue, conn_t *conn_rm)
void	conn_fifo_enqueue_release (conn_fifo_queue_t *queue, conn_t *conn)
conn_t *	conn_fifo_dequeue_release (conn_fifo_queue_t *queue)
void	conn_tcp_release (conn_tcp_t *conn_tcp)
void	conn_udp_release (conn_udp_t *conn_udp)
void	conn_release (conn_t *conn)
void	conn_udp_vectors_reset (conn_udp_t *conn_udp)
conn_udp_t *	conn_udp_new (config_t *cfg, int family)
conn_t *	conn_new_tcp (int fd, config_t *cfg, int ip_version, struct sockaddr_storage *client_ip, struct sockaddr_storage *local_ip)
conn_t *	conn_listener_provision (config_t *cfg, int family, int protocol, char *err_buf, size_t err_buf_len)
conn_t *	conn_lru_cache_get (conn_t **lru, uint64_t id)
bool	conn_tcp_id_assign (uint64_t *id, conn_t **lru, uint64_t *base)
void	conn_tcp_report_metrics (conn_tcp_t *conn_tcp, metrics_t *metrics)

Macro Definition Documentation

CONN_IS_TCP_CONN

#define CONN_IS_TCP_CONN

(

conn

)

conn->lc == 1 && conn->proto == 1

Marco that returns true if conn (conn_t struct) is a TCP connection

CONN_IS_TCP_LISTENER

#define CONN_IS_TCP_LISTENER

(

conn

)

conn->lc == 0 && conn->proto == 1

Marco that returns true if conn (conn_t struct) is a TCP listener

CONN_IS_UDP_LISTENER

#define CONN_IS_UDP_LISTENER

(

conn

)

conn->lc == 0 && conn->proto == 0

Marco that returns true if conn (conn_t struct) is a UDP listener

Typedef Documentation

conn_fifo_queue_t

typedef struct conn_fifo_queue_s conn_fifo_queue_t

Connection object FIFO queue. New objects are enqueued (added) to the tail of the queue, and objects are dequeued (removed) from head of the queue.

conn_t

typedef struct conn_s conn_t

Structure holds data common to TCP and UDP connections.

conn_tcp_state_t

typedef enum conn_tcp_state_e conn_tcp_state_t

Enumerated TCP connection states.

conn_tcp_t

typedef struct conn_tcp_s conn_tcp_t

Structure holds data specific to TCP listener connection.

conn_udp_t

typedef struct conn_udp_s conn_udp_t

Structure holds data specific to UDP listener connection.

listener_start_error_t

typedef enum listener_start_error_e listener_start_error_t

Enumerated error returned by listener_start() function.

Enumeration Type Documentation

conn_tcp_state_e

enum conn_tcp_state_e

Enumerated TCP connection states.

Enumerator
TCP_CONN_ST_WAIT_FOR_QUERY	Wait for query request (not first one).
TCP_CONN_ST_WAIT_FOR_WRITE	Wait for epoll notification for socket to become "writable".
TCP_CONN_ST_CLOSED_FOR_READ	TCP connection is closed for read (by far end), also known as half close.
TCP_CONN_ST_READ_ERR	There was an error reading from connection socket. Socket is closed and no further reads nor writes are done.
TCP_CONN_ST_CLOSED_FOR_WRITE	TCP connection is was closed for write.
TCP_CONN_ST_WRITE_ERR	There was an error writing to connection socket. Socket is closed and no further reads nor writes are done.
TCP_CONN_ST_QUERY_SIZE_TOOLARGE	Query size received over TCP connection exceeds RIP_NS_PACKETSZ.

listener_start_error_e

enum listener_start_error_e

Enumerated error returned by listener_start() function.

Enumerator
LISTENER_ERR_SOCKET	Socket create error.
LISTENER_ERR_SOCKET_OPT_REUSEADDR	Error setting socket option SO_REUSEADDR.
LISTENER_ERR_SOCKET_OPT_REUSEPORT	Error setting socket option SO_REUSEPORT.
LISTENER_ERR_BIND	Error binding socket.
LISTENER_ERR_LISTEN	Error calling listen() on socket, applies to TCP only.
LISTENER_ERR_SOCKET_OPT_IP_PKTINFO	Error setting socket option IP_PKTINFO.
LISTENER_ERR_SOCKET_OPT_IPV6_V6ONLY	Error setting socket option IPV6_V6ONLY.
LISTENER_ERR_SOCKET_OPT_IPV6_RECVPKTINFO	Error setting socket option IPV6_RECVPKTINFO.
LISTENER_ERR_SOCKET_OPT_RCVBUF	Error setting socket option IPV6_RECVPKTINFO.
LISTENER_ERR_SOCKET_OPT_SNDBUF	Error setting socket option IPV6_RECVPKTINFO.

Function Documentation

conn_fifo_dequeue_gen()

conn_t * conn_fifo_dequeue_gen

(

conn_fifo_queue_t *

queue

)

Remove (dequeue) a connection object from generic fifo queue.

Parameters

queue

Queue to remove connection object from.

Returns

On success returns object, otherwise there are no entries in the queue and returns NULL.

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conn_fifo_dequeue_read()

conn_t * conn_fifo_dequeue_read

(

conn_fifo_queue_t *

queue

)

Remove (dequeue) a connection object from read fifo queue.

Parameters

queue

Read queue to remove connection object from.

Returns

On success returns connection object, otherwise there are no entries in the queue and returns NULL.

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conn_fifo_dequeue_release()

conn_t * conn_fifo_dequeue_release

(

conn_fifo_queue_t *

queue

)

Remove (dequeue) a generic object from fifo queue.

Parameters

queue

Queue to remove connection object from.

Returns

On success returns object, otherwise there are no entries in the queue and returns NULL.

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conn_fifo_dequeue_write()

conn_t * conn_fifo_dequeue_write

(

conn_fifo_queue_t *

queue

)

Remove (dequeue) a connection object from write fifo queue.

Parameters

queue

Write queue to remove connection object from.

Returns

On success returns connection object, otherwise there are no entries in the queue and returns NULL.

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conn_fifo_enqueue_gen()

void conn_fifo_enqueue_gen	(	conn_fifo_queue_t *	queue,
		conn_t *	conn
	)

Add (enqueue) a connection object to generic fifo queue.

Parameters

queue	Queue to add object to.
conn	Object to queue up.

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conn_fifo_enqueue_read()

void conn_fifo_enqueue_read	(	conn_fifo_queue_t *	queue,
		conn_t *	conn
	)

Add (enqueue) a connection object to read fifo queue.

Parameters

queue	Read queue to add connection object to.
conn	Connection object to queue up.

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conn_fifo_enqueue_release()

void conn_fifo_enqueue_release	(	conn_fifo_queue_t *	queue,
		conn_t *	conn
	)

Add (enqueue) a connection object to release fifo queue.

Parameters

queue	Queue to add object to.
conn	Object to queue up.

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conn_fifo_enqueue_write()

void conn_fifo_enqueue_write	(	conn_fifo_queue_t *	queue,
		conn_t *	conn
	)

Add (enqueue) a connection object to write fifo queue.

Parameters

queue	Write queue to add connection object to.
conn	Connection object to queue up.

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conn_fifo_remove_from_read_queue()

void conn_fifo_remove_from_read_queue	(	conn_fifo_queue_t *	queue,
		conn_t *	conn_rm
	)

Remove conn from read queue.

Parameters

queue	Read queue to remove conn object from.
conn_rm	Conn object to remove from queue.

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conn_fifo_remove_from_write_queue()

void conn_fifo_remove_from_write_queue	(	conn_fifo_queue_t *	queue,
		conn_t *	conn_rm
	)

Remove conn from write queue.

Parameters

queue	Write queue to remove conn object from.
conn_rm	Conn object to remove from queue.

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conn_listener_provision()

conn_t * conn_listener_provision	(	config_t *	cfg,
		int	family,
		int	protocol,
		char *	err_buf,
		size_t	err_buf_len
	)

Provision a new TCP or UDP listener and return the corresponding connection conn_t object.

Listener is started and associated with new connection object. New connection object is initialized meaning it has all necessary buffers allocated.

Parameters

cfg	Configuration object that has settings: udp_conn_vector_len,
family	IP family to start a listener for, valid options are: AF_INET, AF_INET6.
protocol	Protocol to start listener for, valid options are: IPPROTO_TCP, IPPROTO_UDP.
err_buf	Buffer where to store error message if error was encountered. If NULL no message is stored.
err_buf_len	Length of error buffer.

Returns

On success returns a newly allocated and active connection object. On error returns NULL and message is populated into error buffer.

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conn_lru_cache_get()

conn_t * conn_lru_cache_get	(	conn_t **	lru,
		uint64_t	id
	)

Get entry in TCP connection LRU cache and also update LRU state (entry is set as MRU).

Parameters

lru	Pointer to LRU cache.
id	Entry key to look for.

Returns

On success returns a pointer to connection in LRU cache. Entry place in LRU is updated. Otherwise returns NULL indicating that entry was not found in LRU cache.

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conn_new_tcp()

conn_t * conn_new_tcp	(	int	fd,
		config_t *	cfg,
		int	ip_version,
		struct sockaddr_storage *	client_ip,
		struct sockaddr_storage *	local_ip
	)

Create a new TCP connection object for an established TCP connection.

Parameters

fd	Socket for TCP connection.
cfg	Application configuration to get various settings from.
ip_version	IP version this connection is for, 0=IPv4, 1=IPv6.
client_ip	Client IP address.
local_ip	Local IP address.

Returns

Returns a newly allocated and initialized TCP connection object.

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conn_release()

void conn_release

(

conn_t *

conn

)

Free memory associated with conn_t object and free object it self.

Parameters

conn	Connection object to release.

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conn_tcp_id_assign()

bool conn_tcp_id_assign	(	uint64_t *	id,
		conn_t **	lru,
		uint64_t *	base
	)

Assign a new TCP connection ID.

Parameters

id	Where to store newly assigned TCP connection ID.
lru	TCP connection LRU cache, used to verify uniqueness of connection ID being assigned.
base	Base for connection ID. (Base is unique per Vectorloop object.

Returns

Returns true if connection ID was assigned, otherwise returns false.

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conn_tcp_release()

void conn_tcp_release

(

conn_tcp_t *

conn_tcp

)

Free memory associated with conn_tcp_t object and free object it self.

Parameters

conn_tcp

TCP connection object to release.

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conn_tcp_report_metrics()

void conn_tcp_report_metrics	(	conn_tcp_t *	conn_tcp,
		metrics_t *	metrics
	)

Report TCP metrics for a query.

Parameters

conn_tcp	TCP connection to report metrics for.
metrics	Metrics object where to report metrics.

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conn_udp_new()

conn_udp_t * conn_udp_new	(	config_t *	cfg,
		int	family
	)

Create a new UDP connection object

Parameters

cfg	Application configuration to get various settings from.
family	IP family: AF_INET or AF_INET6.

Returns

Returns a newly allocated and initialized UDP connection object.

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conn_udp_release()

void conn_udp_release

(

conn_udp_t *

conn_udp

)

Free memory associated with conn_udp_t object and free object it self.

Parameters

conn_udp

UDP connection object to release.

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conn_udp_vectors_reset()

void conn_udp_vectors_reset

(

conn_udp_t *

conn_udp

)

Reset UDP connection vectors so the can be reused for next iteration of read/resolve/send of DNS queries.

Parameters

conn_udp

UDP connection to reset vectors for.

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