Initial commit of code

README.md

@@ -1,2 +1,88 @@
 # dnsseeder
 Go Language dns seeder for the Twister P2P network
+
+This is a dns seeder for the [Twister P2P network](http://twister.net.co/)
+
+It is based on the original twister-seeder https://github.com/miguelfreitas/twister-seeder
+
+
+
+> **NOTE:** This repository is under ongoing development and
+is likely to break over time. Use at your own risk.
+
+
+## Installing
+
+Simply use go get to download the code:
+
+    $ go get github.com/gombadi/dnsseeder
+
+Dependencies are handled by the Go vendor directory.
+
+Note: This means the codebase requires Go 1.5 or higher and use of GO15VENDOREXPERIMENT=1
+
+
+## Usage
+
+    $ dnsseeder -h <domain respond to>
+
+An easy way to run the program is with tmux or screen. This enables you to log out and leave the program running.
+
+```
+
+Command line Options:
+-h hostname to serve 
+-p port to listen on
+-d Produce debug output
+-v Produce verbose output
+-v Produce stats output
+
+```
+
+An easy way to run the program is with the following script. Change to suit your system.
+
+```
+
+#!/bin/bash
+
+LOGDIR=${HOME}/goseederlogs/
+
+mkdir -p ${LOGDIR}
+
+# pass through the logging level needed
+if [ -z ${1} ]; then
+        LOGLV="-v"
+else
+        LOGLV="${1}"
+fi
+
+cd
+echo
+echo "======= Run the Go Language dnsseed ======="
+echo
+${HOME}/go/bin/dnsseeder -h <host.to.serve> -p <port.to.listen.on> ${LOGLV} 2>&1 | tee ${LOGDIR}/$(date +%F-%s)-goseeder.log
+
+
+```
+
+
+## RUNNING AS NON-ROOT
+
+Typically, you'll need root privileges to listen to port 53 (name service).
+
+One solution is using an iptables rule (Linux only) to redirect it to
+a non-privileged port:
+
+$ iptables -t nat -A PREROUTING -p udp --dport 53 -j REDIRECT --to-port 5353
+
+If properly configured, this will allow you to run dnsseeder in userspace, using
+the -p 5353 option.
+
+
+## License
+
+For the DNS library license see https://github.com/miekg/dns
+
+For the bitcoin library license see https://github.com/btcsuite/btcd
+
+

crawler.go

@@ -0,0 +1,234 @@
+package main
+
+import (
+	"errors"
+	"log"
+	"net"
+	"strconv"
+	"time"
+
+	"github.com/btcsuite/btcd/wire"
+)
+
+// crawlTwistee runs in a goroutine, crawls the remote ip and updates the master
+// list of currently active addresses
+func crawlTwistee(tw *Twistee) {
+
+	if config.debug {
+		log.Printf("status - start crawl: twistee %s status: %v:%v lastcrawl: %s\n",
+			net.JoinHostPort(tw.na.IP.String(),
+				strconv.Itoa(int(tw.na.Port))),
+			tw.status,
+			tw.rating,
+			time.Since(tw.crawlStart).String())
+	}
+
+	tw.crawlActive = true
+	tw.crawlStart = time.Now()
+
+	defer crawlEnd(tw)
+
+	// connect to the remote ip and ask them for their addr list
+	ras, err := crawlIP(tw)
+	if err != nil {
+		// update the fact that we have not connected to this twistee
+		tw.lastTry = time.Now()
+		tw.connectFails++
+		// update the status of this failed twistee
+		switch tw.status {
+		case statusRG:
+			if tw.rating += 25; tw.rating > 30 {
+				tw.status = statusWG
+			}
+		case statusCG:
+			if tw.rating += 25; tw.rating >= 50 {
+				tw.status = statusWG
+			}
+		case statusWG:
+			if tw.rating += 30; tw.rating >= 100 {
+				tw.status = statusNG // not able to connect to this twistee so ignore
+			}
+		}
+		// no more to do so return which will shutdown the goroutine & call
+		// the deffered cleanup
+		if config.verbose {
+			log.Printf("debug - failed crawl: twistee %s newstatus: %v:%v\n",
+				net.JoinHostPort(tw.na.IP.String(),
+					strconv.Itoa(int(tw.na.Port))),
+				tw.status,
+				tw.rating)
+		}
+		return
+	}
+
+	// succesful connection and addresses received so mark status
+	if tw.status != statusCG {
+		tw.status = statusCG
+	}
+	tw.rating = 0
+	tw.connectFails = 0
+	tw.lastConnect = time.Now()
+	tw.lastTry = time.Now()
+
+	added := 0
+
+	// loop through all the received network addresses and add to thelist if not present
+	for _, na := range ras {
+		// a new network address so add to the system
+		if x := config.seeder.addNa(na); x == true {
+			added++
+		}
+	}
+
+	if config.verbose {
+		log.Printf("status - crawl done: twistee: %s newstatus: %v.%v received_addr: %v added_addr: %v CrawlTime: %s\n",
+			net.JoinHostPort(tw.na.IP.String(),
+				strconv.Itoa(int(tw.na.Port))),
+			tw.status,
+			tw.rating,
+			len(ras),
+			added,
+			time.Since(tw.crawlStart).String())
+	}
+
+	// goroutine ends. deffered cleanup runs
+}
+
+// crawlEnd is a deffered func to update theList after a crawl is all done
+func crawlEnd(tw *Twistee) {
+	tw.crawlActive = false
+	// FIXME - scan for long term crawl active twistees. Dial timeout is 10 seconds
+	// so should be done in under 5 minutes
+}
+
+// crawlIP retrievs a slice of ip addresses from a client
+func crawlIP(tw *Twistee) ([]*wire.NetAddress, error) {
+
+	ip := tw.na.IP.String()
+	port := strconv.Itoa(int(tw.na.Port))
+	// get correct formatting for ipv6 addresses
+	dialString := net.JoinHostPort(ip, port)
+
+	conn, err := net.DialTimeout("tcp", dialString, time.Second*10)
+	if err != nil {
+		if config.debug {
+			log.Printf("error - Could not connect to %s - %v\n", ip, err)
+		}
+		return nil, err
+	}
+
+	defer conn.Close()
+	if config.verbose {
+		log.Printf("%s - Connected to remote address. Last connect was %v ago\n", ip, time.Since(tw.lastConnect).String())
+	}
+
+	// First command to remote end needs to be a version command
+	// last parameter is lastblock
+	msgver, err := wire.NewMsgVersionFromConn(conn, NOUNCE, 0)
+	if err != nil {
+		log.Printf("error - NewMsgVer from conn: %v\n", err)
+		return nil, err
+	}
+
+	err = wire.WriteMessage(conn, msgver, PVER, TWISTNET)
+	if err != nil {
+		// Log and handle the error
+		log.Printf("error - %s:%s Write Message: %v\n", ip, port, err)
+		return nil, err
+	}
+
+	// first message received should be version
+	msg, _, err := wire.ReadMessage(conn, PVER, TWISTNET)
+	if err != nil {
+		// Log and handle the error
+		log.Printf("error - %s:%s Read Message after sending version: %v\n", ip, port, err)
+		return nil, err
+	}
+
+	switch msg := msg.(type) {
+	case *wire.MsgVersion:
+		// The message is a pointer to a MsgVersion struct.
+		if config.debug {
+			log.Printf("%s - Remote version: %v\n", ip, msg.ProtocolVersion)
+		}
+	default:
+		if config.debug {
+			log.Printf("error: expected Version Message but received: %v\n", msg.Command())
+		}
+		return nil, errors.New("Error. Did not receive expected Version message from remote client")
+	}
+
+	// FIXME - update twistee client version with what they just said
+
+	// send verack command
+	msgverack := wire.NewMsgVerAck()
+
+	err = wire.WriteMessage(conn, msgverack, PVER, TWISTNET)
+	if err != nil {
+		// Log and handle the error
+		log.Printf("error - %s:%s Writing Message Ver Ack failed: %v\n", ip, port, err)
+		return nil, err
+	}
+
+	// second message received should be verack
+	msg, _, err = wire.ReadMessage(conn, PVER, TWISTNET)
+	if err != nil {
+		// Log and handle the error
+		log.Printf("error - %s:%s Reading Message expected Ver Ack: %v\n", ip, port, err)
+		return nil, err
+	}
+
+	switch msg := msg.(type) {
+	case *wire.MsgVerAck:
+		if config.debug {
+			// The message is a pointer to a MsgVersion struct.
+			log.Printf("%s - received Version Ack\n", ip)
+		}
+	default:
+		if config.debug {
+			log.Printf("error: expected Version Ack Message but received: %v\n", msg.Command())
+		}
+		return nil, errors.New("Error. Did not receive expected Version Ack message from remote client")
+	}
+
+	// send getaddr command
+	msgGetAddr := wire.NewMsgGetAddr()
+
+	err = wire.WriteMessage(conn, msgGetAddr, PVER, TWISTNET)
+	if err != nil {
+		// Log and handle the error
+		log.Printf("error - %s:%s writing message Get Addr: %v\n", ip, port, err)
+		return nil, err
+	}
+
+	dowhile := true
+	for dowhile == true {
+
+		// Using the Bitcoin lib for the Twister Net means it does not understand some
+		// of the commands and will error. We can ignore these as we are only
+		// interested in the addr message and its content.
+		msgaddr, _, _ := wire.ReadMessage(conn, PVER, TWISTNET)
+		if msgaddr != nil {
+			switch msg := msgaddr.(type) {
+			case *wire.MsgAddr:
+				// received the addrt message so return the result
+				if config.debug {
+					log.Printf("%s - received valid addr message\n", ip)
+				}
+				return msg.AddrList, nil
+				dowhile = false
+			default:
+				if config.debug {
+					log.Printf("%s - ignoring message - %v\n", ip, msg.Command())
+				}
+			}
+		}
+	}
+
+	// should never get here but need a return command
+	return nil, nil
+}
+
+/*
+
+ */