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rule_addr.go
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rule_addr.go
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package main
import (
"fmt"
"net/netip"
"sort"
"github.com/samber/lo"
)
func (r *Rule) checkCIDR(addrs []Addr) (map[netip.Prefix]struct{}, error) {
m := make(map[netip.Prefix]struct{}, len(addrs))
for i := range addrs {
addr := addrs[i]
cidr, err := netip.ParsePrefix(addr.CidrUser)
if err != nil {
return nil, fmt.Errorf("%s is an invalid CIDR", addr.CidrUser)
}
cidr = cidr.Masked()
addrs[i].CidrStandard = cidr.String()
for k := range m {
if cidr.Overlaps(k) {
return nil, fmt.Errorf("%s overlaps with %s", cidr, k)
}
}
m[cidr] = struct{}{}
}
return m, nil
}
func (r *Rule) checkSrcCIDR() (map[netip.Prefix]struct{}, error) {
m, err := r.checkCIDR(r.AddrSrcArr)
if err != nil {
return nil, fmt.Errorf("failed to check src addrs: %w", err)
}
return m, nil
}
func (r *Rules) addSrcCIDRPriority(rule *Rule) error {
m, err := rule.checkSrcCIDR()
if err != nil {
return err
}
err = r.checkCIDRLimit(r.srcCIDRPriorities, m)
if err != nil {
return fmt.Errorf("source CIDR limit: %w", err)
}
for k := range m {
r.srcCIDRPriorities[k] = append(r.srcCIDRPriorities[k], rule.Priority)
}
return nil
}
func (r *Rule) checkDstCIDR() (map[netip.Prefix]struct{}, error) {
m, err := r.checkCIDR(r.AddrDstArr)
if err != nil {
return nil, fmt.Errorf("failed to check dst addrs: %w", err)
}
return m, nil
}
func (r *Rules) addDstCIDRPriority(rule *Rule) error {
m, err := rule.checkDstCIDR()
if err != nil {
return err
}
err = r.checkCIDRLimit(r.dstCIDRPriorities, m)
if err != nil {
return fmt.Errorf("destination CIDR limit: %w", err)
}
for k := range m {
r.dstCIDRPriorities[k] = append(r.dstCIDRPriorities[k], rule.Priority)
}
return nil
}
func (r *Rules) checkCIDRLimit(mExist map[netip.Prefix][]uint32, mAdding map[netip.Prefix]struct{}) error {
nAdding := 0
for k := range mAdding {
if _, ok := mExist[k]; !ok {
nAdding++
}
}
if total := len(mExist) + nAdding; total > int(ipMaxEntries) {
return fmt.Errorf("the number of entry %d exceeds the limit %d", total, ipMaxEntries)
}
return nil
}
func (r *Rules) fixCIDRPriority(m map[netip.Prefix][]uint32) {
prefixes := lo.Keys(m)
sort.Slice(prefixes, func(i, j int) bool {
a, b := prefixes[i], prefixes[j]
if a.Bits() < b.Bits() {
return true
}
if a.Bits() > b.Bits() {
return false
}
ipA, ipB := a.Addr(), b.Addr()
return ipA.Less(ipB)
})
length := len(prefixes)
for i := range prefixes {
prev := prefixes[i]
for j := i + 1; j < length; j++ {
curr := prefixes[j]
if prev.Overlaps(curr) {
// prev CIDR contains curr CIDR
// then append all priority of prev to curr
// because curr is part of prev
m[curr] = append(m[curr], m[prev]...)
// remove duplicated priority
// not required, but for performance
m[curr] = lo.Uniq(m[curr])
}
}
}
}
func (r *Rules) fixSrcCIDRPriority() {
r.fixCIDRPriority(r.srcCIDRPriorities)
}
func (r *Rules) fixDstCIDRPriority() {
r.fixCIDRPriority(r.dstCIDRPriorities)
}