cidr.go

// Copyright 2018 Authors of Cilium
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package policy

import (
	"net"

	"github.com/cilium/cilium/pkg/ip"
	"github.com/cilium/cilium/pkg/policy/api"
)

// getPrefixesFromCIDR fetches all CIDRs referred to by the specified slice
// and returns them as regular golang CIDR objects.
func getPrefixesFromCIDR(cidrs api.CIDRSlice) []*net.IPNet {
	result, _ := ip.ParseCIDRs(cidrs.StringSlice())
	return result
}

// GetPrefixesFromCIDRSet fetches all CIDRs referred to by the specified slice
// and returns them as regular golang CIDR objects.
//
// Assumes that validation already occurred on 'rules'.
func GetPrefixesFromCIDRSet(rules api.CIDRRuleSlice) []*net.IPNet {
	cidrs := api.ComputeResultantCIDRSet(rules)
	return getPrefixesFromCIDR(cidrs)
}

// GetCIDRPrefixes runs through the specified 'rules' to find every reference
// to a CIDR in the rules, and returns a slice containing all of these CIDRs.
// Multiple rules referring to the same CIDR will result in multiple copies of
// the CIDR in the returned slice.
//
// Assumes that validation already occurred on 'rules'.
func GetCIDRPrefixes(rules api.Rules) []*net.IPNet {
	if len(rules) == 0 {
		return nil
	}
	res := make([]*net.IPNet, 0, 32)
	for _, r := range rules {
		for _, ir := range r.Ingress {
			if len(ir.FromCIDR) > 0 {
				res = append(res, getPrefixesFromCIDR(ir.FromCIDR)...)
			}
			if len(ir.FromCIDRSet) > 0 {
				res = append(res, GetPrefixesFromCIDRSet(ir.FromCIDRSet)...)
			}
		}
		for _, er := range r.Egress {
			if len(er.ToCIDR) > 0 {
				res = append(res, getPrefixesFromCIDR(er.ToCIDR)...)
			}
			if len(er.ToCIDRSet) > 0 {
				res = append(res, GetPrefixesFromCIDRSet(er.ToCIDRSet)...)
			}
		}
	}
	return res
}