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Add applyiptables4nattemplate chain element
Signed-off-by: Sergey Shlyanin <sergey.shlyanin@xored.com>
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Sergey Shlyanin
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May 10, 2022
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123 changes: 123 additions & 0 deletions
123
pkg/kernel/networkservice/applyiptables4nattemplate/common.go
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,123 @@ | ||
| // Copyright (c) 2022 Xored Software Inc and others. | ||
| // | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
| // | ||
| // 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. | ||
|
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| //go:build linux | ||
| // +build linux | ||
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| package applyiptables4nattemplate | ||
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| import ( | ||
| "bytes" | ||
| "fmt" | ||
| "log" | ||
| "os" | ||
| "strings" | ||
|
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| "github.com/edwarnicke/exechelper" | ||
| "github.com/pkg/errors" | ||
| ) | ||
|
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| type applyIPTablesKey struct { | ||
| } | ||
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| type iptableManagerImpl struct { | ||
| } | ||
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| // IPTablesManager provides methods for iptables nat rules management | ||
| type IPTablesManager interface { | ||
| Get() (string, error) | ||
| Restore(string) error | ||
| Apply(string) error | ||
| } | ||
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| func (m *iptableManagerImpl) Get() (string, error) { | ||
| cmdStr := "iptables-save" | ||
| buf := bytes.NewBuffer([]byte{}) | ||
| err := exechelper.Run(cmdStr, | ||
| exechelper.WithStdout(buf), | ||
| exechelper.WithStderr(buf), | ||
| ) | ||
| if err != nil { | ||
| err = errors.Wrapf(err, "%s", buf.String()) | ||
| return "", err | ||
| } | ||
|
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| return buf.String(), nil | ||
| } | ||
|
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| func (m *iptableManagerImpl) Apply(rulesTemplate string) error { | ||
| rules := strings.Split(rulesTemplate, "\n") | ||
|
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| for _, rule := range rules { | ||
| // Remove possible tabs from a multistring template | ||
| rule = strings.Trim(rule, "\t ") | ||
| arguments := strings.Split(rule, " ") | ||
| log.Println(rule) | ||
|
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| cmdStr := "iptables -t nat" | ||
| buf := bytes.NewBuffer([]byte{}) | ||
| err := exechelper.Run(cmdStr, | ||
| exechelper.WithArgs(arguments...), | ||
| exechelper.WithStdout(buf), | ||
| exechelper.WithStderr(buf), | ||
| ) | ||
| if err != nil { | ||
| err = errors.Wrapf(err, "%s", buf.String()) | ||
| return err | ||
| } | ||
| } | ||
|
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| return nil | ||
| } | ||
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| func (m *iptableManagerImpl) writeTmpRule(rules string) (string, error) { | ||
| fo, err := os.CreateTemp("/tmp", "rules-*") | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
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| defer func() { _ = fo.Close() }() | ||
| _, err = fo.WriteString(rules) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
|
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| return fo.Name(), nil | ||
| } | ||
|
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| func (m *iptableManagerImpl) Restore(rules string) error { | ||
| // Save rules to a temp file | ||
| tmpFile, err := m.writeTmpRule(rules) | ||
| if err != nil { | ||
| return err | ||
| } | ||
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| defer func() { _ = os.Remove(tmpFile) }() | ||
|
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| // Restore rules | ||
| cmdStr := fmt.Sprintf("iptables-restore %s", tmpFile) | ||
| buf := bytes.NewBuffer([]byte{}) | ||
| err = exechelper.Run(cmdStr, | ||
| exechelper.WithStdout(buf), | ||
| exechelper.WithStderr(buf), | ||
| ) | ||
| if err != nil { | ||
| err = errors.Wrapf(err, "%s", buf.String()) | ||
| return err | ||
| } | ||
|
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| return nil | ||
| } |
115 changes: 115 additions & 0 deletions
115
pkg/kernel/networkservice/applyiptables4nattemplate/server.go
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,115 @@ | ||
| // Copyright (c) 2022 Xored Software Inc and others. | ||
| // | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
| // | ||
| // 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. | ||
|
|
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| //go:build linux | ||
| // +build linux | ||
|
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| // Package applyiptables4nattemplate provides chain element for setup iptables nat rules | ||
| package applyiptables4nattemplate | ||
|
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| import ( | ||
| "context" | ||
|
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| "github.com/golang/protobuf/ptypes/empty" | ||
| "github.com/pkg/errors" | ||
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| "github.com/networkservicemesh/api/pkg/api/networkservice" | ||
| "github.com/networkservicemesh/api/pkg/api/networkservice/mechanisms/kernel" | ||
| "github.com/networkservicemesh/sdk/pkg/networkservice/core/next" | ||
| "github.com/networkservicemesh/sdk/pkg/networkservice/utils/metadata" | ||
| ) | ||
|
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| type iptablesServer struct { | ||
| manager IPTablesManager | ||
| } | ||
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| // Option is an option pattern for applyiptables4nattemplate chain elements | ||
| type Option func(server *iptablesServer) | ||
|
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| // WithIPTablesManager provides an option to change IPTablesManager for a chain element | ||
| func WithIPTablesManager(iptable IPTablesManager) Option { | ||
| return func(server *iptablesServer) { | ||
| server.manager = iptable | ||
| } | ||
| } | ||
|
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| // NewServer - returns a new networkservice.NetworkServiceServer that modify IPTables rules | ||
| // by mechanism provided template on Request and rollbacks rules changes on Close | ||
| func NewServer(options ...Option) networkservice.NetworkServiceServer { | ||
| result := &iptablesServer{ | ||
| manager: &iptableManagerImpl{}, | ||
| } | ||
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| for _, option := range options { | ||
| option(result) | ||
| } | ||
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| return result | ||
| } | ||
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| func (s *iptablesServer) Request(ctx context.Context, request *networkservice.NetworkServiceRequest) (*networkservice.Connection, error) { | ||
| ctxMap := metadata.Map(ctx, metadata.IsClient(s)) | ||
| _, rulesWasApplied := ctxMap.Load(applyIPTablesKey{}) | ||
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| conn, err := next.Server(ctx).Request(ctx, request) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| // Check refresh requests | ||
| if !rulesWasApplied { | ||
| mechanism := kernel.ToMechanism(request.GetConnection().GetMechanism()) | ||
| if mechanism != nil && mechanism.GetIPTables4NatTemplate() != "" { | ||
| rules, err := mechanism.EvaluateIPTables4NatTemplate(request.GetConnection()) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| initialRules, err := s.manager.Get() | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| ctxMap.Store(applyIPTablesKey{}, initialRules) | ||
|
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| err = s.manager.Apply(rules) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| } | ||
| } | ||
|
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| return conn, nil | ||
| } | ||
|
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| func (s *iptablesServer) Close(ctx context.Context, conn *networkservice.Connection) (*empty.Empty, error) { | ||
| _, err := next.Server(ctx).Close(ctx, conn) | ||
|
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| var restoreErr error | ||
| ctxMap := metadata.Map(ctx, metadata.IsClient(s)) | ||
| if initialRules, rulesWasApplied := ctxMap.Load(applyIPTablesKey{}); rulesWasApplied { | ||
| restoreErr = s.manager.Restore(initialRules.(string)) | ||
| } | ||
|
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| if err != nil && restoreErr != nil { | ||
| return nil, errors.Wrap(err, restoreErr.Error()) | ||
| } | ||
| if restoreErr != nil { | ||
| return nil, restoreErr | ||
| } | ||
|
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| return &empty.Empty{}, err | ||
| } |