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Files
WireGold/gold/link/send.go
2022-04-13 11:34:14 +08:00

78 lines
2.0 KiB
Go

package link
import (
"errors"
"fmt"
"math/rand"
"github.com/fumiama/WireGold/gold/head"
"github.com/sirupsen/logrus"
)
// WriteAndPut 向 peer 发包并将包放回缓存池
func (l *Link) WriteAndPut(p *head.Packet, istransfer bool) (n int, err error) {
teatype := uint8(rand.Intn(16))
if len(p.Data) <= int(l.me.mtu) {
if !istransfer {
p.FillHash()
p.Data = l.Encode(teatype, p.Data)
}
defer p.Put()
return l.write(p, teatype, uint32(len(p.Data)), 0, istransfer, false)
}
if !istransfer {
p.FillHash()
p.Data = l.Encode(teatype, p.Data)
}
data := p.Data
ttl := p.TTL
totl := uint32(len(data))
i := 0
packet := head.SelectPacket()
*packet = *p
for ; int(totl)-i > int(l.me.mtu); i += int(l.me.mtu) {
logrus.Debugln("[link] split frag", i, ":", i+int(l.me.mtu), ", remain:", int(totl)-i-int(l.me.mtu))
packet.Data = data[:int(l.me.mtu)]
cnt, err := l.write(packet, teatype, totl, uint16(uint(i)>>3), istransfer, true)
n += cnt
if err != nil {
return n, err
}
data = data[int(l.me.mtu):]
packet.TTL = ttl
}
packet.Put()
p.Data = data
cnt, err := l.write(p, teatype, totl, uint16(uint(i)>>3), istransfer, false)
p.Put()
n += cnt
return n, err
}
// write 向 peer 发一个包
func (l *Link) write(p *head.Packet, teatype uint8, datasz uint32, offset uint16, istransfer, hasmore bool) (n int, err error) {
var d []byte
var cl func()
if istransfer {
if p.Flags&0x4000 == 0x4000 && len(p.Data) > int(l.me.mtu) {
return len(p.Data), errors.New("drop dont fragmnet big trans packet")
}
d, cl = p.Marshal(nil, teatype, 0, 0, false, false)
} else {
d, cl = p.Marshal(l.me.me, teatype, datasz, offset, false, hasmore)
}
if d == nil {
return 0, errors.New("[link] ttl exceeded")
}
if err == nil {
peerep := l.endpoint
if peerep == nil {
return 0, errors.New("[link] nil endpoint of " + p.Dst.String())
}
logrus.Debugln("[link] write", len(d), "bytes data from ep", l.me.myep.LocalAddr(), "to", peerep, "offset:", fmt.Sprintf("%04x", offset))
n, err = l.me.myep.WriteToUDP(d, peerep)
cl()
}
return
}