kubernetes/pkg/util/iptables/save_restore.go
Dan Winship 7c27cf0b9b Simplify iptables-save parsing
We don't need to parse out the counter values from the iptables-save
output (since they are always 0 for the chains we care about). Just
parse the chain names themselves.

Also, all of the callers of GetChainLines() pass it input that
contains only a single table, so just assume that, rather than
carefully parsing only a single table's worth of the input.
2022-06-28 08:39:32 -04:00

53 lines
1.4 KiB
Go

/*
Copyright 2014 The Kubernetes Authors.
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 iptables
import (
"bytes"
"fmt"
)
// MakeChainLine return an iptables-save/restore formatted chain line given a Chain
func MakeChainLine(chain Chain) string {
return fmt.Sprintf(":%s - [0:0]", chain)
}
// GetChainsFromTable parses iptables-save data to find the chains that are defined. It
// assumes that save contains a single table's data, and returns a map with keys for every
// chain defined in that table.
func GetChainsFromTable(save []byte) map[Chain]struct{} {
chainsMap := make(map[Chain]struct{})
for {
i := bytes.Index(save, []byte("\n:"))
if i == -1 {
break
}
start := i + 2
save = save[start:]
end := bytes.Index(save, []byte(" "))
if i == -1 {
// shouldn't happen, but...
break
}
chain := Chain(save[:end])
chainsMap[chain] = struct{}{}
save = save[end:]
}
return chainsMap
}