github.com/containerd/nerdctl/v2@v2.0.0-beta.5.0.20240520001846-b5758f54fa28/pkg/portutil/iptable/iptables.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package iptable
    18  
    19  import (
    20  	"regexp"
    21  	"strconv"
    22  	"strings"
    23  )
    24  
    25  // ParseIPTableRules takes a slice of iptables rules as input and returns a slice of
    26  // uint64 containing the parsed destination port numbers from the rules.
    27  func ParseIPTableRules(rules []string) []uint64 {
    28  	ports := []uint64{}
    29  
    30  	// Regex to match the '--dports' option followed by the port number
    31  	dportRegex := regexp.MustCompile(`--dports ((,?\d+)+)`)
    32  
    33  	for _, rule := range rules {
    34  		matches := dportRegex.FindStringSubmatch(rule)
    35  		if len(matches) > 1 {
    36  			for _, _match := range strings.Split(matches[1], ",") {
    37  				port64, err := strconv.ParseUint(_match, 10, 16)
    38  				if err != nil {
    39  					continue
    40  				}
    41  				ports = append(ports, port64)
    42  			}
    43  		}
    44  	}
    45  
    46  	return ports
    47  }