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/*
* xfrd-tcp.h - XFR (transfer) Daemon TCP system header file. Manages tcp conn.
*
* Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
*
* See LICENSE for the license.
*
*/
#ifndef XFRD_TCP_H
#define XFRD_TCP_H
#include "xfrd.h"
struct buffer;
struct xfrd_zone;
struct xfrd_soa;
struct xfrd_state;
struct region;
struct dname;
struct acl_options;
struct xfrd_tcp_pipeline;
typedef struct xfrd_tcp xfrd_tcp_t;
typedef struct xfrd_tcp_set xfrd_tcp_set_t;
/*
* A set of xfrd tcp connections.
*/
struct xfrd_tcp_set {
/* tcp connections, each has packet and read/wr state */
struct xfrd_tcp_pipeline *tcp_state[XFRD_MAX_TCP];
/* number of TCP connections in use. */
int tcp_count;
/* TCP timeout. */
int tcp_timeout;
/* rbtree with pipelines sorted by master */
rbtree_t* pipetree;
/* double linked list of zones waiting for a TCP connection */
struct xfrd_zone *tcp_waiting_first, *tcp_waiting_last;
};
/*
* Structure to keep track of an open tcp connection
* The xfrd tcp connection is used to first make a request
* Then to receive the answer packet(s).
*/
struct xfrd_tcp {
/* tcp connection state */
/* state: reading or writing */
uint8_t is_reading;
/* how many bytes have been read/written - total,
incl. tcp length bytes */
uint32_t total_bytes;
/* msg len bytes */
uint16_t msglen;
/* fd of connection. -1 means unconnected */
int fd;
/* packet buffer of connection */
struct buffer* packet;
};
/* use illegal pointer value to denote skipped ID number.
* if this does not work, we can allocate with malloc */
#define TCP_NULL_SKIP ((struct xfrd_zone*)-1)
/* the number of ID values (16 bits) for a pipeline */
#define ID_PIPE_NUM 65536
/**
* Structure to keep track of a pipelined set of queries on
* an open tcp connection. The queries may be answered with
* interleaved answer packets, the ID number disambiguates.
* Sorted by the master IP address so you can use lookup with
* smaller-or-equal to find the tcp connection most suitable.
*/
struct xfrd_tcp_pipeline {
/* the rbtree node, sorted by IP and nr of unused queries */
rbnode_t node;
/* destination IP address */
#ifdef INET6
struct sockaddr_storage ip;
#else
struct sockaddr_in ip;
#endif /* INET6 */
socklen_t ip_len;
/* number of unused IDs. used IDs are waiting to send their query,
* or have been sent but not not all answer packets have been received.
* Sorted by num_unused, so a lookup smaller-equal for 65536 finds the
* connection to that master that has the most free IDs. */
int num_unused;
/* number of skip-set IDs (these are 'in-use') */
int num_skip;
int handler_added;
/* the event handler for this pipe (it'll disambiguate by ID) */
struct event handler;
/* the tcp connection to use for reading */
xfrd_tcp_t* tcp_r;
/* the tcp connection to use for writing, if it is done successfully,
* then the first zone from the sendlist can be removed. */
xfrd_tcp_t* tcp_w;
/* once a byte has been written, handshake complete */
int connection_established;
/* list of queries that want to send, first to get write event,
* if NULL, no write event interest */
struct xfrd_zone* tcp_send_first, *tcp_send_last;
/* the unused and id arrays must be last in the structure */
/* per-ID number the queries that have this ID number, every
* query owns one ID numbers (until it is done). NULL: unused
* When a query is done but not all answer-packets have been
* consumed for that ID number, the rest is skipped, this
* is denoted with the pointer-value TCP_NULL_SKIP, the ids that
* are skipped are not on the unused list. They may be
* removed once the last answer packet is skipped.
* ID_PIPE_NUM-num_unused values in the id array are nonNULL (either
* a zone pointer or SKIP) */
struct xfrd_zone* id[ID_PIPE_NUM];
/* unused ID numbers; the first part of the array contains the IDs */
uint16_t unused[ID_PIPE_NUM];
};
/* create set of tcp connections */
xfrd_tcp_set_t* xfrd_tcp_set_create(struct region* region);
/* init tcp state */
xfrd_tcp_t* xfrd_tcp_create(struct region* region, size_t bufsize);
/* obtain tcp connection for a zone (or wait) */
void xfrd_tcp_obtain(xfrd_tcp_set_t* set, struct xfrd_zone* zone);
/* release tcp connection for a zone (starts waiting) */
void xfrd_tcp_release(xfrd_tcp_set_t* set, struct xfrd_zone* zone);
/* release tcp pipe entirely (does not stop the zones inside it) */
void xfrd_tcp_pipe_release(xfrd_tcp_set_t* set, struct xfrd_tcp_pipeline* tp,
int conn);
/* use tcp connection to start xfr */
void xfrd_tcp_setup_write_packet(struct xfrd_tcp_pipeline* tp,
struct xfrd_zone* zone);
/* initialize tcp_state for a zone. Opens the connection. true on success.*/
int xfrd_tcp_open(xfrd_tcp_set_t* set, struct xfrd_tcp_pipeline* tp, struct xfrd_zone* zone);
/* read data from tcp, maybe partial read */
void xfrd_tcp_read(struct xfrd_tcp_pipeline* tp);
/* write data to tcp, maybe a partial write */
void xfrd_tcp_write(struct xfrd_tcp_pipeline* tp, struct xfrd_zone* zone);
/* handle tcp pipe events */
void xfrd_handle_tcp_pipe(int fd, short event, void* arg);
/*
* Read from a stream connection (size16)+packet into buffer.
* returns value is
* -1 on error.
* 0 on short read, call back later.
* 1 on completed read.
* On first call, make sure total_bytes = 0, msglen=0, buffer_clear().
* and the packet and fd need to be set.
*/
int conn_read(xfrd_tcp_t* conn);
/*
* Write to a stream connection (size16)+packet.
* return value is
* -1 on error. 0 on short write, call back later. 1 completed write.
* On first call, make sure total_bytes=0, msglen=buffer_limit(),
* buffer_flipped(). packet and fd need to be set.
*/
int conn_write(xfrd_tcp_t* conn);
/* setup DNS packet for a query of this type */
void xfrd_setup_packet(struct buffer* packet,
uint16_t type, uint16_t klass, const struct dname* dname, uint16_t qid);
/* write soa in network format to the packet buffer */
void xfrd_write_soa_buffer(struct buffer* packet,
const struct dname* apex, struct xfrd_soa* soa);
/* use acl address to setup sockaddr struct, returns length of addr. */
socklen_t xfrd_acl_sockaddr_to(struct acl_options* acl,
#ifdef INET6
struct sockaddr_storage *to);
#else
struct sockaddr_in *to);
#endif /* INET6 */
socklen_t xfrd_acl_sockaddr_frm(struct acl_options* acl,
#ifdef INET6
struct sockaddr_storage *frm);
#else
struct sockaddr_in *frm);
#endif /* INET6 */
/* create pipeline tcp structure */
struct xfrd_tcp_pipeline* xfrd_tcp_pipeline_create(region_type* region);
#endif /* XFRD_TCP_H */
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