JAVA开发

JAVA开发

流程

初始化模型（规则树）

将规则添加到前缀树中

提取前缀树中规则

模型更新

验证

根据端口名获取端口（不存在直接添加）

Port p = device.getPort("default");

public Port getPort(String name) {
    nameToPort.putIfAbsent(name, new Port(name, this));
    return this.nameToPort.get(name);
    }

规则插入树结构

public IndexedRules traverseSrc(Rule rule, ArrayList<Rule> ret, int size) {
        IndexedRules t = this;
        if (ret != null) t.read(rule, ret, size);
        long srcIp = rule.getSrc();//获取IP
        for (int i = 0; i < rule.getSrcSuffix(); i++) {//遍历前缀
            long bit = (srcIp >> i) & 1;右移i位 并将其结果与1进行and运算
            t = t.buildNext(bit == 0 ? 0 : 1);
            if (ret != null) t.read(rule, ret, size);
        }
        if (ret != null) t.exploreSrc(rule, ret, size);
        return t.traverse(rule, size);
}
//read() method
    public void read(Rule rule, ArrayList<Rule> ret, int size) {
        if (this.dst == null) return;
        IndexedRules t = this.dst;
        if (ret != null) ret.addAll(t.getRules());
        long dstIp = rule.getMatch().longValue();
        for (int i = 0; i < rule.getPrefix() - (32 - size); i++) {
            long bit = (dstIp >> (size - 1 - i)) & 1;
            t = (bit == 0) ? t.left : t.right;
            if (t == null) return;
            if (ret != null) ret.addAll(t.getRules());
        }
        if (ret != null) t.explore(ret);
    }
//buildNext() method
    private IndexedRules buildNext(int flag) {
        if (flag == 0) {
            if (this.left == null) {
                this.left = new IndexedRules();
            }
            return this.left;
        } else {
            if (this.right == null) {
                this.right = new IndexedRules();
            }
            return this.right;    
}
    }
//explore() method
    private void explore(ArrayList<Rule> ret) {
        if (this.left != null) this.left.explore(ret);
        if (this.right != null) this.right.explore(ret);
        ret.addAll(this.getRules());
 }
//traverse() method
    public IndexedRules traverse(Rule rule, int size) {
        if (this.dst == null) this.dst = new IndexedRules();
        IndexedRules t = this.dst;

        long dstIp = rule.getMatch().longValue();
        for (int i = 0; i < rule.getPrefix() - (32 - size); i++) {
            long bit = (dstIp >> (size - 1 - i)) & 1;
            t = t.buildNext(bit == 0 ? 0 : 1);
        }
        return t;
    }
//exploreSrc() method
    private void exploreSrc(Rule rule, ArrayList<Rule> ret, int size) {
        if (this.left != null) {
            this.left.read(rule, ret, size);
            this.left.exploreSrc(rule, ret, size);
        }
        if (this.right != null) {
            this.right.read(rule, ret, size);
            this.right.exploreSrc(rule, ret, size);
        }
    }

/*
test
default rule 0/0 32 ->srcIp=0 getSrcSuffix=0 size=32
*/

模拟测试

假设存在三条转发规则

rule 1 192.168.1.1/24 port1
rule 2 192.168.1.2/16 port2
rule 3 192.168.1.1/25 port3

存在默认规则

rule default 0.0/24 default

过程

1.添加默认规则

调用traverseSrc(default, null, 32)

调用traverse(default,32)

t = t.dst

2.添加规则rule 1 rule 2 rule 3

for循环遍历规则集合[rule 1,rule 2,rule 3]

添加规则rule 1

调用traverseSrc(default, null, 32)

执行

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