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| 1 | +// Copyright 2019-2025 The Liqo Authors |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +package firewall |
| 16 | + |
| 17 | +import ( |
| 18 | + "fmt" |
| 19 | + |
| 20 | + "github.com/google/nftables" |
| 21 | + firewallapi "github.com/liqotech/liqo/apis/networking/v1beta1/firewall" |
| 22 | + "github.com/liqotech/liqo/pkg/firewall/utils" |
| 23 | +) |
| 24 | + |
| 25 | +// cleanSets removes the sets that are no longer used in the firewall configuration and updates the existing ones if their elements differ from the wanted elements. |
| 26 | +func cleanSets(nftconn *nftables.Conn, table *firewallapi.Table) error { |
| 27 | + // Find the table by name and family |
| 28 | + nftTables, err := nftconn.ListTablesOfFamily(getTableFamily(*table.Family)) |
| 29 | + if err != nil { |
| 30 | + return err |
| 31 | + } |
| 32 | + |
| 33 | + var nftTable *nftables.Table |
| 34 | + for _, t := range nftTables { |
| 35 | + if t.Name == *table.Name { |
| 36 | + nftTable = t |
| 37 | + break |
| 38 | + } |
| 39 | + } |
| 40 | + |
| 41 | + if nftTable == nil { |
| 42 | + // Table does not exist, nothing to clean |
| 43 | + return nil |
| 44 | + } |
| 45 | + |
| 46 | + // Get all existing sets in the table |
| 47 | + nftSets, err := nftconn.GetSets(nftTable) |
| 48 | + if err != nil { |
| 49 | + return err |
| 50 | + } |
| 51 | + |
| 52 | + // Remove sets that are no longer used. |
| 53 | + if err := removeOutdatedSets(nftconn, nftSets, table); err != nil { |
| 54 | + return err |
| 55 | + } |
| 56 | + |
| 57 | + // Update existing sets if their elements differ from the wanted elements. |
| 58 | + if err := updateSetElements(nftconn, nftSets, table); err != nil { |
| 59 | + return err |
| 60 | + } |
| 61 | + |
| 62 | + return nil |
| 63 | +} |
| 64 | + |
| 65 | +// removeOutdatedSets removes the sets that are no longer used in the firewall configuration. |
| 66 | +func removeOutdatedSets(nftconn *nftables.Conn, nftSets []*nftables.Set, table *firewallapi.Table) error { |
| 67 | + // Delete sets that are not used anymore in the table |
| 68 | + usedSetNames := make(map[string]interface{}) |
| 69 | + for _, set := range table.Sets { |
| 70 | + usedSetNames[set.Name] = nil |
| 71 | + } |
| 72 | + |
| 73 | + for _, nftSet := range nftSets { |
| 74 | + if _, used := usedSetNames[nftSet.Name]; !used { |
| 75 | + // Set is not used anymore, delete it |
| 76 | + nftconn.DelSet(nftSet) |
| 77 | + } |
| 78 | + } |
| 79 | + |
| 80 | + return nil |
| 81 | +} |
| 82 | + |
| 83 | +// updateSetElements updates the elements of an existing set, if they differ from the wanted elements. |
| 84 | +func updateSetElements(nftconn *nftables.Conn, nftSets []*nftables.Set, table *firewallapi.Table) error { |
| 85 | + for _, set := range table.Sets { |
| 86 | + // Find the corresponding nftables.Set |
| 87 | + var nftSet *nftables.Set |
| 88 | + for _, ns := range nftSets { |
| 89 | + if ns.Name == set.Name { |
| 90 | + nftSet = ns |
| 91 | + break |
| 92 | + } |
| 93 | + } |
| 94 | + |
| 95 | + if nftSet == nil { |
| 96 | + // Set does not exist, skip |
| 97 | + continue |
| 98 | + } |
| 99 | + |
| 100 | + // Get existing elements of the set |
| 101 | + existingElements, err := nftconn.GetSetElements(nftSet) |
| 102 | + if err != nil { |
| 103 | + return err |
| 104 | + } |
| 105 | + |
| 106 | + // Get wanted elements of the set |
| 107 | + wantedElements, err := genSetElements(&set) |
| 108 | + if err != nil { |
| 109 | + return err |
| 110 | + } |
| 111 | + |
| 112 | + // Check if the set is outdated |
| 113 | + if isSetOutdated(existingElements, wantedElements) { |
| 114 | + // Remove the existing elements and add the wanted ones |
| 115 | + if err := nftconn.SetDeleteElements(nftSet, existingElements); err != nil { |
| 116 | + return err |
| 117 | + } |
| 118 | + if err := nftconn.SetAddElements(nftSet, wantedElements); err != nil { |
| 119 | + return err |
| 120 | + } |
| 121 | + } |
| 122 | + } |
| 123 | + |
| 124 | + return nil |
| 125 | +} |
| 126 | + |
| 127 | +// isSetOutdated checks if the existing set elements differ from the wanted set elements. |
| 128 | +func isSetOutdated(existingElements []nftables.SetElement, wantedElements []nftables.SetElement) bool { |
| 129 | + // If the lengths differ, the set is outdated. |
| 130 | + if len(existingElements) != len(wantedElements) { |
| 131 | + return true |
| 132 | + } |
| 133 | + |
| 134 | + // Build a map of existing elements for quick lookup. |
| 135 | + existingElementsMap := make(map[string]string) |
| 136 | + for _, element := range existingElements { |
| 137 | + existingElementsMap[string(element.Key)] = string(element.Val) |
| 138 | + } |
| 139 | + |
| 140 | + // Check if any wanted element is missing or differs in value. |
| 141 | + for _, wantedElement := range wantedElements { |
| 142 | + val, exists := existingElementsMap[string(wantedElement.Key)] |
| 143 | + if !exists || val != string(wantedElement.Val) { |
| 144 | + return true |
| 145 | + } |
| 146 | + } |
| 147 | + |
| 148 | + return false |
| 149 | +} |
| 150 | + |
| 151 | +// addSets adds the sets that are missing in the nftables configuration. |
| 152 | +func addSets(nftconn *nftables.Conn, sets []firewallapi.Set, nftTable *nftables.Table) error { |
| 153 | + nftSets, err := nftconn.GetSets(nftTable) |
| 154 | + if err != nil { |
| 155 | + return err |
| 156 | + } |
| 157 | + existingSetNames := make(map[string]struct{}) |
| 158 | + for _, nftSet := range nftSets { |
| 159 | + existingSetNames[nftSet.Name] = struct{}{} |
| 160 | + } |
| 161 | + |
| 162 | + for _, set := range sets { |
| 163 | + if _, exists := existingSetNames[set.Name]; !exists { |
| 164 | + _, err := addSet(nftconn, nftTable, &set) |
| 165 | + if err != nil { |
| 166 | + return err |
| 167 | + } |
| 168 | + } |
| 169 | + } |
| 170 | + return nil |
| 171 | +} |
| 172 | + |
| 173 | +// addSet adds a new set to the nftables configuration. |
| 174 | +func addSet(nftconn *nftables.Conn, table *nftables.Table, set *firewallapi.Set) (*nftables.Set, error) { |
| 175 | + dataType, err := getSetDataType(set.DataType) |
| 176 | + if err != nil { |
| 177 | + return nil, err |
| 178 | + } |
| 179 | + |
| 180 | + keyType, err := getSetDataType(&set.KeyType) |
| 181 | + if err != nil { |
| 182 | + return nil, err |
| 183 | + } |
| 184 | + |
| 185 | + nftSet := &nftables.Set{ |
| 186 | + Table: table, |
| 187 | + Name: set.Name, |
| 188 | + KeyType: keyType, |
| 189 | + DataType: dataType, |
| 190 | + } |
| 191 | + |
| 192 | + setData, err := genSetElements(set) |
| 193 | + if err != nil { |
| 194 | + return nil, err |
| 195 | + } |
| 196 | + |
| 197 | + err = nftconn.AddSet(nftSet, setData) |
| 198 | + if err != nil { |
| 199 | + return nil, err |
| 200 | + } |
| 201 | + |
| 202 | + return nftSet, nil |
| 203 | +} |
| 204 | + |
| 205 | +func genSetElements(set *firewallapi.Set) ([]nftables.SetElement, error) { |
| 206 | + setData := make([]nftables.SetElement, len(set.Elements)) |
| 207 | + for i, element := range set.Elements { |
| 208 | + data, err := utils.ConvertSetData(element.Data, set.DataType) |
| 209 | + if err != nil { |
| 210 | + return nil, fmt.Errorf("unable to convert set element data: %v", err) |
| 211 | + } |
| 212 | + |
| 213 | + key, err := utils.ConvertSetData(&element.Key, &set.KeyType) |
| 214 | + if err != nil { |
| 215 | + return nil, fmt.Errorf("unable to convert set element key: %v", err) |
| 216 | + } |
| 217 | + |
| 218 | + setData[i] = nftables.SetElement{ |
| 219 | + Key: key, |
| 220 | + Val: data, |
| 221 | + } |
| 222 | + } |
| 223 | + |
| 224 | + return setData, nil |
| 225 | +} |
| 226 | + |
| 227 | +func getSetDataType(dataType *firewallapi.SetDataType) (nftables.SetDatatype, error) { |
| 228 | + if dataType == nil { |
| 229 | + return nftables.SetDatatype{}, nil |
| 230 | + } |
| 231 | + |
| 232 | + switch *dataType { |
| 233 | + case firewallapi.SetTypeIPAddr: |
| 234 | + return nftables.TypeIPAddr, nil |
| 235 | + default: |
| 236 | + return nftables.SetDatatype{}, fmt.Errorf("unsupported set data type: %s", *dataType) |
| 237 | + } |
| 238 | +} |
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