mirror of
https://github.com/fumiama/WireGold.git
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82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
package link
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import (
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"encoding/binary"
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"net"
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"sync"
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"github.com/sirupsen/logrus"
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)
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type Router struct {
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// map[cidr]*Link
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table map[string]*Link
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mu sync.RWMutex
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list []*net.IPNet
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}
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// Accept 判断是否应当接受 ip 发来的包
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func (l *Link) Accept(ip net.IP) bool {
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for _, cidr := range l.allowedips {
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if cidr.Contains(ip) {
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return true
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}
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}
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return false
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}
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// IsToMe 判断是否是发给自己的包
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func (l *Link) IsToMe(ip net.IP) bool {
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return ip.Equal(l.me.me) || ip.Equal(net.IPv4bcast) || isSubnetBcast(ip, &l.me.subnet)
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}
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// SetDefault 设置默认网关
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func (r *Router) SetDefault(l *Link) {
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defnet := &net.IPNet{IP: net.IPv4(0, 0, 0, 0), Mask: net.IPv4Mask(0, 0, 0, 0)}
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r.mu.Lock()
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r.list[len(r.list)-1] = defnet
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r.table[defnet.String()] = l
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r.mu.Unlock()
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}
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// NextHop 得到前往 ip 的下一跳的 link
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func (r *Router) NextHop(cidr string) *Link {
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logrus.Infoln("[router] search for cidr", cidr)
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// TODO: 遍历 r.table，得到正确的下一跳
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// 注意使用 r.mu 读写锁避免竞争
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return r.table[cidr]
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}
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// SetItem 添加一条表项
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func (r *Router) SetItem(ip *net.IPNet, l *Link) {
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r.mu.Lock()
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// 从第一条表项开始匹配
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for i := 0; i < len(r.list); i++ {
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if r.list[i].Contains(ip.IP) {
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// 是同一个网络
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if ip.Mask.String() == r.list[i].Mask.String() {
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logrus.Infoln("[router] change link of item", r.list[i], "from", r.table[r.list[i].String()], "to", l)
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r.table[r.list[i].String()] = l
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break
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}
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// 是新网络
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r.list = append(r.list, nil)
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copy(r.list[i+1:], r.list[i:len(r.list)-1])
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r.list[i] = ip
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r.table[ip.String()] = l
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logrus.Infoln("[router] add item: net =", ip, "link =", l)
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break
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}
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}
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r.mu.Unlock()
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}
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func isSubnetBcast(ip net.IP, subnet *net.IPNet) bool {
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if !subnet.Contains(ip) {
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return false
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}
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maskr := make(net.IPMask, 4)
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binary.LittleEndian.PutUint32(maskr[:], ^binary.LittleEndian.Uint32(subnet.Mask))
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return ip.Mask(maskr).Equal(net.IP(maskr))
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}
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