github.com/mysteriumnetwork/node@v0.0.0-20240516044423-365054f76801/firewall/iptables/chain.go (about)

     1  /*
     2   * Copyright (C) 2019 The "MysteriumNetwork/node" Authors.
     3   *
     4   * This program is free software: you can redistribute it and/or modify
     5   * it under the terms of the GNU General Public License as published by
     6   * the Free Software Foundation, either version 3 of the License, or
     7   * (at your option) any later version.
     8   *
     9   * This program is distributed in the hope that it will be useful,
    10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    12   * GNU General Public License for more details.
    13   *
    14   * You should have received a copy of the GNU General Public License
    15   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    16   */
    17  
    18  package iptables
    19  
    20  import "strconv"
    21  
    22  // Rule is a packet filter rule for IPTables.
    23  type Rule struct {
    24  	chainName string
    25  	action    []string
    26  	ruleSpec  []string
    27  }
    28  
    29  // AppendTo creates a new rule to be appended to the specified chain.
    30  func AppendTo(chainName string) Rule {
    31  	return Rule{
    32  		chainName: chainName,
    33  		action:    []string{"-A", chainName},
    34  	}
    35  }
    36  
    37  // InsertAt creates a new rule to be inserted into the specified chain.
    38  func InsertAt(chainName string, line int) Rule {
    39  	return Rule{
    40  		chainName: chainName,
    41  		action:    []string{"-I", chainName, strconv.Itoa(line)},
    42  	}
    43  }
    44  
    45  // RuleSpec sets the rule specification (see `man iptables`).
    46  func (r Rule) RuleSpec(spec ...string) Rule {
    47  	r.ruleSpec = spec
    48  	return r
    49  }
    50  
    51  // ApplyArgs returns an argument list to be passed to the iptables executable to APPLY the rule.
    52  func (r Rule) ApplyArgs() []string {
    53  	return append(r.action, r.ruleSpec...)
    54  }
    55  
    56  // RemoveArgs returns an argument list to be passed to the iptables executable to REMOVE the rule.
    57  func (r Rule) RemoveArgs() []string {
    58  	return append([]string{"-D", r.chainName}, r.ruleSpec...)
    59  }
    60  
    61  // Equals checks if two Rules are equal.
    62  func (r Rule) Equals(another Rule) bool {
    63  	return r.chainName == another.chainName &&
    64  		equalStringSlice(r.ruleSpec, another.ruleSpec)
    65  }
    66  
    67  func equalStringSlice(a, b []string) bool {
    68  	if len(a) != len(b) {
    69  		return false
    70  	}
    71  	for i := range a {
    72  		if a[i] != b[i] {
    73  			return false
    74  		}
    75  	}
    76  	return true
    77  }