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package sql
import (
"database/sql"
"sync"
"time"
"github.com/jmoiron/sqlx"
_ "github.com/mattn/go-sqlite3" // SQLite database driver
)
const schema = `
CREATE TABLE IF NOT EXISTS rr_question (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
CONSTRAINT name_unique UNIQUE(name)
);
CREATE TABLE IF NOT EXISTS rr_answer (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
CONSTRAINT name_unique UNIQUE(name)
);
CREATE TABLE IF NOT EXISTS rr_type (
id INTEGER PRIMARY KEY,
type INTEGER NOT NULL,
CONSTRAINT type_unique UNIQUE(type)
);
CREATE TABLE IF NOT EXISTS remote_addr (
id INTEGER PRIMARY KEY,
addr BLOB NOT NULL,
CONSTRAINT addr_unique UNIQUE(addr)
);
CREATE TABLE IF NOT EXISTS log (
id INTEGER PRIMARY KEY,
time INTEGER NOT NULL,
hijacked INTEGER NOT NULL,
remote_addr_id INTEGER NOT NULL,
rr_type_id INTEGER NOT NULL,
rr_question_id INTEGER NOT NULL,
FOREIGN KEY (remote_addr_id) REFERENCES remote_addr(id),
FOREIGN KEY (rr_question_id) REFERENCES rr_question(id),
FOREIGN KEY (rr_type_id) REFERENCES rr_type(id)
);
CREATE TABLE IF NOT EXISTS log_rr_answer (
id INTEGER PRIMARY KEY,
log_id INTEGER NOT NULL,
rr_answer_id INTEGER NOT NULL,
FOREIGN KEY (log_id) REFERENCES log(id),
FOREIGN KEY (rr_answer_id) REFERENCES rr_answer(id)
);
CREATE TABLE IF NOT EXISTS cache (
id INTEGER PRIMARY KEY,
key INTEGER NOT NULL,
data TEXT NOT NULL,
CONSTRAINT key_unique UNIQUE(key)
);
`
// Client implements a client for a SQLite database.
type Client struct {
db *sqlx.DB
mu sync.RWMutex
}
// LogEntry represents an entry in the log.
type LogEntry struct {
ID int64 `db:"id"`
Time int64 `db:"time"`
RemoteAddr []byte `db:"remote_addr"`
Hijacked bool `db:"hijacked"`
Qtype uint16 `db:"type"`
Question string `db:"question"`
Answer string `db:"answer"`
}
type cacheEntry struct {
Key uint32 `db:"key"`
Data string `db:"data"`
}
// New creates a new database client for given filename.
func New(filename string) (*Client, error) {
db, err := sqlx.Connect("sqlite3", filename)
if err != nil {
return nil, err
}
// Ensure foreign keys are enabled (defaults to off)
if _, err := db.Exec("PRAGMA foreign_keys = ON"); err != nil {
return nil, err
}
if _, err := db.Exec(schema); err != nil {
return nil, err
}
return &Client{db: db}, nil
}
// ReadLog reads the n most recent entries from the log.
func (c *Client) ReadLog(n int) ([]LogEntry, error) {
c.mu.RLock()
defer c.mu.RUnlock()
query := `
SELECT log.id AS id,
time,
remote_addr.addr AS remote_addr,
hijacked,
type,
rr_question.name AS question,
IFNULL(rr_answer.name, "") AS answer
FROM log
INNER JOIN remote_addr ON remote_addr.id = log.remote_addr_id
INNER JOIN rr_question ON rr_question.id = rr_question_id
INNER JOIN rr_type ON rr_type.id = rr_type_id
LEFT JOIN log_rr_answer ON log_rr_answer.log_id = log.id
LEFT JOIN rr_answer ON rr_answer.id = log_rr_answer.rr_answer_id
WHERE log.id IN (SELECT id FROM log ORDER BY time DESC, id DESC LIMIT $1)
ORDER BY time DESC, rr_answer.id DESC
`
var entries []LogEntry
err := c.db.Select(&entries, query, n)
return entries, err
}
func getOrInsert(tx *sqlx.Tx, table, column string, value interface{}) (int64, error) {
var id int64
err := tx.Get(&id, "SELECT id FROM "+table+" WHERE "+column+" = ?", value)
if err == sql.ErrNoRows {
res, err := tx.Exec("INSERT INTO "+table+" ("+column+") VALUES (?)", value)
if err != nil {
return 0, err
}
return res.LastInsertId()
}
return id, err
}
// WriteLog writes a new entry to the log.
func (c *Client) WriteLog(time time.Time, remoteAddr []byte, hijacked bool, qtype uint16, question string, answers ...string) error {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return err
}
defer tx.Rollback()
typeID, err := getOrInsert(tx, "rr_type", "type", qtype)
if err != nil {
return err
}
questionID, err := getOrInsert(tx, "rr_question", "name", question)
if err != nil {
return err
}
remoteAddrID, err := getOrInsert(tx, "remote_addr", "addr", remoteAddr)
if err != nil {
return err
}
answerIDs := make([]int64, 0, len(answers))
for _, answer := range answers {
answerID, err := getOrInsert(tx, "rr_answer", "name", answer)
if err != nil {
return err
}
answerIDs = append(answerIDs, answerID)
}
hijackedInt := 0
if hijacked {
hijackedInt = 1
}
res, err := tx.Exec("INSERT INTO log (time, hijacked, remote_addr_id, rr_type_id, rr_question_id) VALUES ($1, $2, $3, $4, $5)", time.Unix(), hijackedInt, remoteAddrID, typeID, questionID)
if err != nil {
return err
}
logID, err := res.LastInsertId()
if err != nil {
return err
}
for _, answerID := range answerIDs {
if _, err := tx.Exec("INSERT INTO log_rr_answer (log_id, rr_answer_id) VALUES ($1, $2)", logID, answerID); err != nil {
return err
}
}
return tx.Commit()
}
// DeleteLogBefore deletes all log entries occurring before time t.
func (c *Client) DeleteLogBefore(t time.Time) (err error) {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return nil
}
defer tx.Rollback()
var ids []int64
if err := tx.Select(&ids, "SELECT id FROM log WHERE time < $1", t.Unix()); err != nil {
return err
}
if len(ids) == 0 {
return nil
}
deleteByIds := []string{
"DELETE FROM log_rr_answer WHERE log_id IN (?)",
"DELETE FROM log WHERE id IN (?)",
}
for _, q := range deleteByIds {
query, args, err := sqlx.In(q, ids)
if err != nil {
return err
}
if _, err := tx.Exec(query, args...); err != nil {
return err
}
}
deleteBySelection := []string{
"DELETE FROM rr_type WHERE id NOT IN (SELECT rr_type_id FROM log)",
"DELETE FROM rr_question WHERE id NOT IN (SELECT rr_question_id FROM log)",
"DELETE FROM rr_answer WHERE id NOT IN (SELECT rr_answer_id FROM log_rr_answer)",
"DELETE FROM remote_addr WHERE id NOT IN (SELECT remote_addr_id FROM log)",
}
for _, q := range deleteBySelection {
if _, err := tx.Exec(q); err != nil {
return err
}
}
return tx.Commit()
}
func (c *Client) writeCacheValue(key uint32, data string) error {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return nil
}
defer tx.Rollback()
query := `INSERT INTO cache (key, data) VALUES ($1, $2)
ON CONFLICT(key) DO UPDATE SET data=excluded.data`
if _, err := tx.Exec(query, key, data); err != nil {
return err
}
return tx.Commit()
}
func (c *Client) removeCacheValue(key uint32) error {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return nil
}
defer tx.Rollback()
if _, err := tx.Exec("DELETE FROM cache WHERE key = $1", key); err != nil {
return err
}
return tx.Commit()
}
func (c *Client) truncateCache() error {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return nil
}
defer tx.Rollback()
if _, err := tx.Exec("DELETE FROM cache"); err != nil {
return err
}
return tx.Commit()
}
func (c *Client) readCache() ([]cacheEntry, error) {
c.mu.RLock()
defer c.mu.RUnlock()
var entries []cacheEntry
err := c.db.Select(&entries, "SELECT key, data FROM cache ORDER BY id ASC")
return entries, err
}
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