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Enable discovery gossiping

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This commit is contained in:
Jakob Borg 2014-05-11 19:55:43 -03:00
parent b783169c72
commit 1d602b9efa
5 changed files with 206 additions and 62 deletions
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48
discover/PROTOCOL.md
View File

@ -36,12 +36,28 @@ The Announcement packet has the following structure:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Magic Number (0x029E4C77) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length of Node ID |
| Magic (0x029E4C77) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ /
\ Node ID (variable length) \
\ Node Structure \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Extra Nodes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ /
\ Zero or more Node Structures \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Node Structure:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length of ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ /
\ ID (variable length) \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Addresses |
@ -62,29 +78,37 @@ The Announcement packet has the following structure:
\ IP (variable length) \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Number | 0x0000 |
| Port | 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This is the XDR encoding of:
struct Announcement {
unsigned int MagicNumber;
string NodeID<>;
unsigned int Magic;
Node This;
Node Extra<>;
}
struct Node {
string ID<>;
Address Addresses<>;
}
struct Address {
opaque IP<>;
unsigned short PortNumber;
unsigned short Port;
}
NodeID is padded to a multiple of 32 bits and all fields are in sent in
network (big endian) byte order. In the Address structure, the IP field
can be of three differnt kinds;
The first Node structure contains information about the sending node.
The following zero or more Extra nodes contain information about other
nodes known to the sending node.
In the Address structure, the IP field can be of three differnt kinds;
- A zero length indicates that the IP address should be taken from the
source address of the announcement packet, be it IPv4 or IPv6. The
source address must be a valid unicast address.
source address must be a valid unicast address. This is only valid
in the first node structure, not in the list of extras.
- A four byte length indicates that the address is an IPv4 unicast
address.

132
discover/discover.go
View File

@ -4,6 +4,7 @@ import (
"encoding/hex"
"errors"
"fmt"
"io"
"log"
"net"
"sync"
@ -108,18 +109,34 @@ func (d *Discoverer) announcementPkt() []byte {
}
}
var pkt = AnnounceV2{
Magic: AnnouncementMagicV2,
NodeID: d.myID,
Addresses: addrs,
Magic: AnnouncementMagicV2,
This: Node{d.myID, addrs},
}
return pkt.MarshalXDR()
}
func (d *Discoverer) sendLocalAnnouncements() {
var buf = d.announcementPkt()
var addrs = resolveAddrs(d.listenAddrs)
var pkt = AnnounceV2{
Magic: AnnouncementMagicV2,
This: Node{d.myID, addrs},
}
for {
d.beacon.Send(buf)
pkt.Extra = nil
d.registryLock.RLock()
for node, addrs := range d.registry {
if len(pkt.Extra) == 16 {
break
}
anode := Node{node, resolveAddrs(addrs)}
pkt.Extra = append(pkt.Extra, anode)
}
d.registryLock.RUnlock()
d.beacon.Send(pkt.MarshalXDR())
select {
case <-d.localBcastTick:
@ -144,9 +161,8 @@ func (d *Discoverer) sendExternalAnnouncements() {
var buf []byte
if d.extPort != 0 {
var pkt = AnnounceV2{
Magic: AnnouncementMagicV2,
NodeID: d.myID,
Addresses: []Address{{Port: d.extPort}},
Magic: AnnouncementMagicV2,
This: Node{d.myID, []Address{{Port: d.extPort}}},
}
buf = pkt.MarshalXDR()
} else {
@ -203,7 +219,7 @@ func (d *Discoverer) recvAnnouncements() {
var pkt AnnounceV2
err := pkt.UnmarshalXDR(buf)
if err != nil {
if err != nil && err != io.EOF {
continue
}
@ -211,35 +227,55 @@ func (d *Discoverer) recvAnnouncements() {
dlog.Printf("parsed announcement: %#v", pkt)
}
if pkt.NodeID != d.myID {
var addrs []string
for _, a := range pkt.Addresses {
var nodeAddr string
if len(a.IP) > 0 {
nodeAddr = fmt.Sprintf("%s:%d", net.IP(a.IP), a.Port)
} else {
ua := addr.(*net.UDPAddr)
ua.Port = int(a.Port)
nodeAddr = ua.String()
}
addrs = append(addrs, nodeAddr)
var newNode bool
if pkt.This.ID != d.myID {
n := d.registerNode(addr, pkt.This)
newNode = newNode || n
}
for _, node := range pkt.Extra {
if node.ID != d.myID {
n := d.registerNode(nil, node)
newNode = newNode || n
}
if debug {
dlog.Printf("register: %#v", addrs)
}
if newNode {
select {
case d.forcedBcastTick <- time.Now():
}
d.registryLock.Lock()
_, seen := d.registry[pkt.NodeID]
if !seen {
select {
case d.forcedBcastTick <- time.Now():
}
}
d.registry[pkt.NodeID] = addrs
d.registryLock.Unlock()
}
}
}
func (d *Discoverer) registerNode(addr net.Addr, node Node) bool {
var addrs []string
for _, a := range node.Addresses {
var nodeAddr string
if len(a.IP) > 0 {
nodeAddr = fmt.Sprintf("%s:%d", net.IP(a.IP), a.Port)
addrs = append(addrs, nodeAddr)
} else if addr != nil {
ua := addr.(*net.UDPAddr)
ua.Port = int(a.Port)
nodeAddr = ua.String()
addrs = append(addrs, nodeAddr)
}
}
if len(addrs) == 0 {
if debug {
dlog.Println("no valid address for", node.ID)
}
}
if debug {
dlog.Printf("register: %s -> %#v", node.ID, addrs)
}
d.registryLock.Lock()
_, seen := d.registry[node.ID]
d.registry[node.ID] = addrs
d.registryLock.Unlock()
return !seen
}
func (d *Discoverer) externalLookup(node string) []string {
extIP, err := net.ResolveUDPAddr("udp", d.extServer)
if err != nil {
@ -268,7 +304,7 @@ func (d *Discoverer) externalLookup(node string) []string {
}
buffers.Put(buf)
buf = buffers.Get(256)
buf = buffers.Get(2048)
defer buffers.Put(buf)
n, err := conn.Read(buf)
@ -287,7 +323,7 @@ func (d *Discoverer) externalLookup(node string) []string {
var pkt AnnounceV2
err = pkt.UnmarshalXDR(buf[:n])
if err != nil {
if err != nil && err != io.EOF {
log.Println("discover/external/decode:", err)
return nil
}
@ -297,9 +333,35 @@ func (d *Discoverer) externalLookup(node string) []string {
}
var addrs []string
for _, a := range pkt.Addresses {
for _, a := range pkt.This.Addresses {
nodeAddr := fmt.Sprintf("%s:%d", net.IP(a.IP), a.Port)
addrs = append(addrs, nodeAddr)
}
return addrs
}
func addrToAddr(addr *net.TCPAddr) Address {
if len(addr.IP) == 0 || addr.IP.IsUnspecified() {
return Address{Port: uint16(addr.Port)}
} else if bs := addr.IP.To4(); bs != nil {
return Address{IP: bs, Port: uint16(addr.Port)}
} else if bs := addr.IP.To16(); bs != nil {
return Address{IP: bs, Port: uint16(addr.Port)}
}
return Address{}
}
func resolveAddrs(addrs []string) []Address {
var raddrs []Address
for _, addrStr := range addrs {
addrRes, err := net.ResolveTCPAddr("tcp", addrStr)
if err != nil {
continue
}
addr := addrToAddr(addrRes)
if len(addr.IP) > 0 {
raddrs = append(raddrs, addr)
}
}
return raddrs
}

9
discover/packets.go
View File

@ -11,8 +11,13 @@ type QueryV2 struct {
}
type AnnounceV2 struct {
Magic uint32
NodeID string // max:64
Magic uint32
This Node
Extra []Node // max:16
}
type Node struct {
ID string // max:64
Addresses []Address // max:16
}

66
discover/packets_xdr.go
View File

@ -59,16 +59,13 @@ func (o AnnounceV2) MarshalXDR() []byte {
func (o AnnounceV2) encodeXDR(xw *xdr.Writer) (int, error) {
xw.WriteUint32(o.Magic)
if len(o.NodeID) > 64 {
o.This.encodeXDR(xw)
if len(o.Extra) > 16 {
return xw.Tot(), xdr.ErrElementSizeExceeded
}
xw.WriteString(o.NodeID)
if len(o.Addresses) > 16 {
return xw.Tot(), xdr.ErrElementSizeExceeded
}
xw.WriteUint32(uint32(len(o.Addresses)))
for i := range o.Addresses {
o.Addresses[i].encodeXDR(xw)
xw.WriteUint32(uint32(len(o.Extra)))
for i := range o.Extra {
o.Extra[i].encodeXDR(xw)
}
return xw.Tot(), xw.Error()
}
@ -86,7 +83,58 @@ func (o *AnnounceV2) UnmarshalXDR(bs []byte) error {
func (o *AnnounceV2) decodeXDR(xr *xdr.Reader) error {
o.Magic = xr.ReadUint32()
o.NodeID = xr.ReadStringMax(64)
(&o.This).decodeXDR(xr)
_ExtraSize := int(xr.ReadUint32())
if _ExtraSize > 16 {
return xdr.ErrElementSizeExceeded
}
o.Extra = make([]Node, _ExtraSize)
for i := range o.Extra {
(&o.Extra[i]).decodeXDR(xr)
}
return xr.Error()
}
func (o Node) EncodeXDR(w io.Writer) (int, error) {
var xw = xdr.NewWriter(w)
return o.encodeXDR(xw)
}
func (o Node) MarshalXDR() []byte {
var buf bytes.Buffer
var xw = xdr.NewWriter(&buf)
o.encodeXDR(xw)
return buf.Bytes()
}
func (o Node) encodeXDR(xw *xdr.Writer) (int, error) {
if len(o.ID) > 64 {
return xw.Tot(), xdr.ErrElementSizeExceeded
}
xw.WriteString(o.ID)
if len(o.Addresses) > 16 {
return xw.Tot(), xdr.ErrElementSizeExceeded
}
xw.WriteUint32(uint32(len(o.Addresses)))
for i := range o.Addresses {
o.Addresses[i].encodeXDR(xw)
}
return xw.Tot(), xw.Error()
}
func (o *Node) DecodeXDR(r io.Reader) error {
xr := xdr.NewReader(r)
return o.decodeXDR(xr)
}
func (o *Node) UnmarshalXDR(bs []byte) error {
var buf = bytes.NewBuffer(bs)
var xr = xdr.NewReader(buf)
return o.decodeXDR(xr)
}
func (o *Node) decodeXDR(xr *xdr.Reader) error {
o.ID = xr.ReadStringMax(64)
_AddressesSize := int(xr.ReadUint32())
if _AddressesSize > 16 {
return xdr.ErrElementSizeExceeded

13
xdr/reader.go
View File

@ -72,20 +72,25 @@ func (r *Reader) ReadUint16() uint16 {
}
func (r *Reader) ReadUint32() uint32 {
var n int
if r.err != nil {
return 0
}
_, r.err = io.ReadFull(r.r, r.b[:4])
r.tot += 4
n, r.err = io.ReadFull(r.r, r.b[:4])
if n < 4 {
return 0
}
r.tot += n
return uint32(r.b[3]) | uint32(r.b[2])<<8 | uint32(r.b[1])<<16 | uint32(r.b[0])<<24
}
func (r *Reader) ReadUint64() uint64 {
var n int
if r.err != nil {
return 0
}
_, r.err = io.ReadFull(r.r, r.b[:8])
r.tot += 8
n, r.err = io.ReadFull(r.r, r.b[:8])
r.tot += n
return uint64(r.b[7]) | uint64(r.b[6])<<8 | uint64(r.b[5])<<16 | uint64(r.b[4])<<24 |
uint64(r.b[3])<<32 | uint64(r.b[2])<<40 | uint64(r.b[1])<<48 | uint64(r.b[0])<<56
}