bridge: Add macspoofchk support

The new macspoofchk field is added to the bridge plugin to support
anti-mac-spoofing.
When the parameter is enabled, traffic is limited to the mac addresses
of the container interface (the veth peer that is placed in the
container ns).
Any traffic that exits the pod is checked against the source mac address
that is expected. If the mac address is different, the frames are
dropped.

The implementation is using nftables and should only be used on nodes
that support it.

Signed-off-by: Edward Haas <edwardh@redhat.com>

vendor/github.com/networkplumbing/go-nft/nft/config/chain.go

@@ -0,0 +1,80 @@
+/*
+ * This file is part of the go-nft project
+ *
+ * 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.
+ *
+ * Copyright 2021 Red Hat, Inc.
+ *
+ */
+
+package config
+
+import (
+	"github.com/networkplumbing/go-nft/nft/schema"
+)
+
+// AddChain appends the given chain to the nftable config.
+// The chain is added without an explicit action (`add`).
+// Adding multiple times the same chain has no affect when the config is applied.
+func (c *Config) AddChain(chain *schema.Chain) {
+	nftable := schema.Nftable{Chain: chain}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// DeleteChain appends a given chain to the nftable config
+// with the `delete` action.
+// Attempting to delete a non-existing chain, results with a failure when the config is applied.
+// The chain must not contain any rules or be used as a jump target.
+func (c *Config) DeleteChain(chain *schema.Chain) {
+	nftable := schema.Nftable{Delete: &schema.Objects{Chain: chain}}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// FlushChain appends a given chain to the nftable config
+// with the `flush` action.
+// All rules under the chain are removed (when applied).
+// Attempting to flush a non-existing chain, results with a failure when the config is applied.
+func (c *Config) FlushChain(chain *schema.Chain) {
+	nftable := schema.Nftable{Flush: &schema.Objects{Chain: chain}}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// LookupChain searches the configuration for a matching chain and returns it.
+// The chain is matched first by the table and chain name.
+// Other matching fields are optional (for matching base chains).
+// Mutating the returned chain will result in mutating the configuration.
+func (c *Config) LookupChain(toFind *schema.Chain) *schema.Chain {
+	for _, nftable := range c.Nftables {
+		if chain := nftable.Chain; chain != nil {
+			match := chain.Table == toFind.Table && chain.Family == toFind.Family && chain.Name == toFind.Name
+			if match {
+				if t := toFind.Type; t != "" {
+					match = match && chain.Type == t
+				}
+				if h := toFind.Hook; h != "" {
+					match = match && chain.Hook == h
+				}
+				if p := toFind.Prio; p != nil {
+					match = match && chain.Prio != nil && *chain.Prio == *p
+				}
+				if p := toFind.Policy; p != "" {
+					match = match && chain.Policy == p
+				}
+				if match {
+					return chain
+				}
+			}
+		}
+	}
+	return nil
+}

vendor/github.com/networkplumbing/go-nft/nft/config/config.go

@@ -0,0 +1,59 @@
+/*
+ * This file is part of the go-nft project
+ *
+ * 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.
+ *
+ * Copyright 2021 Red Hat, Inc.
+ *
+ */
+
+package config
+
+import (
+	"encoding/json"
+
+	"github.com/networkplumbing/go-nft/nft/schema"
+)
+
+type Config struct {
+	schema.Root
+}
+
+// New returns a new nftables config structure.
+func New() *Config {
+	c := &Config{}
+	c.Nftables = []schema.Nftable{}
+	return c
+}
+
+// ToJSON returns the JSON encoding of the nftables config.
+func (c *Config) ToJSON() ([]byte, error) {
+	return json.Marshal(*c)
+}
+
+// FromJSON decodes the provided JSON-encoded data and populates the nftables config.
+func (c *Config) FromJSON(data []byte) error {
+	if err := json.Unmarshal(data, c); err != nil {
+		return err
+	}
+	return nil
+}
+
+// FlushRuleset adds a command to the nftables config that erases all the configuration when applied.
+// It is commonly used as the first config instruction, followed by a declarative configuration.
+// When used, any previous configuration is flushed away before adding the new one.
+// Calling FlushRuleset updates the configuration and will take effect only
+// when applied on the system.
+func (c *Config) FlushRuleset() {
+	c.Nftables = append(c.Nftables, schema.Nftable{Flush: &schema.Objects{Ruleset: true}})
+}

vendor/github.com/networkplumbing/go-nft/nft/config/rule.go

@@ -0,0 +1,94 @@
+/*
+ * This file is part of the go-nft project
+ *
+ * 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.
+ *
+ * Copyright 2021 Red Hat, Inc.
+ *
+ */
+
+package config
+
+import (
+	"bytes"
+	"encoding/json"
+
+	"github.com/networkplumbing/go-nft/nft/schema"
+)
+
+// AddRule appends the given rule to the nftable config.
+// The rule is added without an explicit action (`add`).
+// Adding multiple times the same rule will result in multiple identical rules when applied.
+func (c *Config) AddRule(rule *schema.Rule) {
+	nftable := schema.Nftable{Rule: rule}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// DeleteRule appends a given rule to the nftable config
+// with the `delete` action.
+// A rule is identified by its handle ID and it must be present in the given rule.
+// Attempting to delete a non-existing rule, results with a failure when the config is applied.
+// A common usage is to use LookupRule() and then to pass the result to DeleteRule.
+func (c *Config) DeleteRule(rule *schema.Rule) {
+	nftable := schema.Nftable{Delete: &schema.Objects{Rule: rule}}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// LookupRule searches the configuration for a matching rule and returns it.
+// The rule is matched first by the table and chain.
+// Other matching fields are optional (nil or an empty string arguments imply no-matching).
+// Mutating the returned chain will result in mutating the configuration.
+func (c *Config) LookupRule(toFind *schema.Rule) []*schema.Rule {
+	var rules []*schema.Rule
+
+	for _, nftable := range c.Nftables {
+		if r := nftable.Rule; r != nil {
+			match := r.Table == toFind.Table && r.Family == toFind.Family && r.Chain == toFind.Chain
+			if match {
+				if h := toFind.Handle; h != nil {
+					match = match && r.Handle != nil && *r.Handle == *h
+				}
+				if i := toFind.Index; i != nil {
+					match = match && r.Index != nil && *r.Index == *i
+				}
+				if co := toFind.Comment; co != "" {
+					match = match && r.Comment == co
+				}
+				if toFindStatements := toFind.Expr; toFindStatements != nil {
+					if match = match && len(toFindStatements) == len(r.Expr); match {
+						for i, toFindStatement := range toFindStatements {
+							equal, err := areStatementsEqual(toFindStatement, r.Expr[i])
+							match = match && err == nil && equal
+						}
+					}
+				}
+				if match {
+					rules = append(rules, r)
+				}
+			}
+		}
+	}
+	return rules
+}
+
+func areStatementsEqual(statementA, statementB schema.Statement) (bool, error) {
+	statementARow, err := json.Marshal(statementA)
+	if err != nil {
+		return false, err
+	}
+	statementBRow, err := json.Marshal(statementB)
+	if err != nil {
+		return false, err
+	}
+	return bytes.Equal(statementARow, statementBRow), nil
+}

vendor/github.com/networkplumbing/go-nft/nft/config/table.go

@@ -0,0 +1,63 @@
+/*
+ * This file is part of the go-nft project
+ *
+ * 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.
+ *
+ * Copyright 2021 Red Hat, Inc.
+ *
+ */
+
+package config
+
+import (
+	"github.com/networkplumbing/go-nft/nft/schema"
+)
+
+// AddTable appends the given table to the nftable config.
+// The table is added without an explicit action (`add`).
+// Adding multiple times the same table has no effect when the config is applied.
+func (c *Config) AddTable(table *schema.Table) {
+	nftable := schema.Nftable{Table: table}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// DeleteTable appends a given table to the nftable config
+// with the `delete` action.
+// Attempting to delete a non-existing table, results with a failure when the config is applied.
+// All chains and rules under the table are removed as well (when applied).
+func (c *Config) DeleteTable(table *schema.Table) {
+	nftable := schema.Nftable{Delete: &schema.Objects{Table: table}}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// FlushTable appends a given table to the nftable config
+// with the `flush` action.
+// All chains and rules under the table are removed (when applied).
+// Attempting to flush a non-existing table, results with a failure when the config is applied.
+func (c *Config) FlushTable(table *schema.Table) {
+	nftable := schema.Nftable{Flush: &schema.Objects{Table: table}}
+	c.Nftables = append(c.Nftables, nftable)
+}
+
+// LookupTable searches the configuration for a matching table and returns it.
+// Mutating the returned table will result in mutating the configuration.
+func (c *Config) LookupTable(toFind *schema.Table) *schema.Table {
+	for _, nftable := range c.Nftables {
+		if t := nftable.Table; t != nil {
+			if t.Name == toFind.Name && t.Family == toFind.Family {
+				return t
+			}
+		}
+	}
+	return nil
+}