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endpoints.go
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endpoints.go
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// Copyright (c) 2016-2018 Tigera, Inc. All rights reserved.
//
// 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.
package rules
import (
log "github.com/sirupsen/logrus"
"github.com/projectcalico/felix/hashutils"
. "github.com/projectcalico/felix/iptables"
"github.com/projectcalico/felix/proto"
)
const (
dropEncap = true
dontDropEncap = false
)
func (r *DefaultRuleRenderer) WorkloadEndpointToIptablesChains(
ifaceName string,
epMarkMapper EndpointMarkMapper,
adminUp bool,
ingressPolicies []string,
egressPolicies []string,
profileIDs []string,
) []*Chain {
result := []*Chain{}
result = append(result,
// Chain for traffic _to_ the endpoint.
r.endpointIptablesChain(
ingressPolicies,
profileIDs,
ifaceName,
PolicyInboundPfx,
ProfileInboundPfx,
WorkloadToEndpointPfx,
"", // No fail-safe chains for workloads.
chainTypeNormal,
adminUp,
r.filterAllowAction, // Workload endpoint chains are only used in the filter table
dontDropEncap,
),
// Chain for traffic _from_ the endpoint.
r.endpointIptablesChain(
egressPolicies,
profileIDs,
ifaceName,
PolicyOutboundPfx,
ProfileOutboundPfx,
WorkloadFromEndpointPfx,
"", // No fail-safe chains for workloads.
chainTypeNormal,
adminUp,
r.filterAllowAction, // Workload endpoint chains are only used in the filter table
dropEncap,
),
)
if r.KubeIPVSSupportEnabled {
// Chain for setting endpoint mark of an endpoint.
result = append(result,
r.endpointSetMarkChain(
ifaceName,
epMarkMapper,
SetEndPointMarkPfx,
),
)
}
return result
}
func (r *DefaultRuleRenderer) HostEndpointToFilterChains(
ifaceName string,
epMarkMapper EndpointMarkMapper,
ingressPolicyNames []string,
egressPolicyNames []string,
ingressForwardPolicyNames []string,
egressForwardPolicyNames []string,
profileIDs []string,
) []*Chain {
log.WithField("ifaceName", ifaceName).Debug("Rendering filter host endpoint chain.")
result := []*Chain{}
result = append(result,
// Chain for output traffic _to_ the endpoint.
r.endpointIptablesChain(
egressPolicyNames,
profileIDs,
ifaceName,
PolicyOutboundPfx,
ProfileOutboundPfx,
HostToEndpointPfx,
ChainFailsafeOut,
chainTypeNormal,
true, // Host endpoints are always admin up.
r.filterAllowAction,
dontDropEncap,
),
// Chain for input traffic _from_ the endpoint.
r.endpointIptablesChain(
ingressPolicyNames,
profileIDs,
ifaceName,
PolicyInboundPfx,
ProfileInboundPfx,
HostFromEndpointPfx,
ChainFailsafeIn,
chainTypeNormal,
true, // Host endpoints are always admin up.
r.filterAllowAction,
dontDropEncap,
),
// Chain for forward traffic _to_ the endpoint.
r.endpointIptablesChain(
egressForwardPolicyNames,
profileIDs,
ifaceName,
PolicyOutboundPfx,
ProfileOutboundPfx,
HostToEndpointForwardPfx,
"", // No fail-safe chains for forward traffic.
chainTypeForward,
true, // Host endpoints are always admin up.
r.filterAllowAction,
dontDropEncap,
),
// Chain for forward traffic _from_ the endpoint.
r.endpointIptablesChain(
ingressForwardPolicyNames,
profileIDs,
ifaceName,
PolicyInboundPfx,
ProfileInboundPfx,
HostFromEndpointForwardPfx,
"", // No fail-safe chains for forward traffic.
chainTypeForward,
true, // Host endpoints are always admin up.
r.filterAllowAction,
dontDropEncap,
),
)
if r.KubeIPVSSupportEnabled {
// Chain for setting endpoint mark of an endpoint.
result = append(result,
r.endpointSetMarkChain(
ifaceName,
epMarkMapper,
SetEndPointMarkPfx,
),
)
}
return result
}
func (r *DefaultRuleRenderer) HostEndpointToRawChains(
ifaceName string,
ingressPolicyNames []string,
egressPolicyNames []string,
) []*Chain {
log.WithField("ifaceName", ifaceName).Debug("Rendering raw (untracked) host endpoint chain.")
return []*Chain{
// Chain for traffic _to_ the endpoint.
r.endpointIptablesChain(
egressPolicyNames,
nil, // We don't render profiles into the raw table.
ifaceName,
PolicyOutboundPfx,
ProfileOutboundPfx,
HostToEndpointPfx,
ChainFailsafeOut,
chainTypeUntracked,
true, // Host endpoints are always admin up.
AcceptAction{},
dontDropEncap,
),
// Chain for traffic _from_ the endpoint.
r.endpointIptablesChain(
ingressPolicyNames,
nil, // We don't render profiles into the raw table.
ifaceName,
PolicyInboundPfx,
ProfileInboundPfx,
HostFromEndpointPfx,
ChainFailsafeIn,
chainTypeUntracked,
true, // Host endpoints are always admin up.
AcceptAction{},
dontDropEncap,
),
}
}
func (r *DefaultRuleRenderer) HostEndpointToMangleChains(
ifaceName string,
preDNATPolicyNames []string,
) []*Chain {
log.WithField("ifaceName", ifaceName).Debug("Rendering pre-DNAT host endpoint chain.")
return []*Chain{
// Chain for traffic _from_ the endpoint. Pre-DNAT policy does not apply to
// outgoing traffic through a host endpoint.
r.endpointIptablesChain(
preDNATPolicyNames,
nil, // We don't render profiles into the raw table.
ifaceName,
PolicyInboundPfx,
ProfileInboundPfx,
HostFromEndpointPfx,
ChainFailsafeIn,
chainTypePreDNAT,
true, // Host endpoints are always admin up.
r.mangleAllowAction,
dontDropEncap,
),
}
}
type endpointChainType int
const (
chainTypeNormal endpointChainType = iota
chainTypeUntracked
chainTypePreDNAT
chainTypeForward
)
func (r *DefaultRuleRenderer) endpointSetMarkChain(
name string,
epMarkMapper EndpointMarkMapper,
endpointPrefix string,
) *Chain {
rules := []Rule{}
chainName := EndpointChainName(endpointPrefix, name)
if endPointMark, err := epMarkMapper.GetEndpointMark(name); err == nil {
// Set endpoint mark.
rules = append(rules, Rule{
Action: SetMaskedMarkAction{
Mark: endPointMark,
Mask: epMarkMapper.GetMask()},
})
}
return &Chain{
Name: chainName,
Rules: rules,
}
}
func (r *DefaultRuleRenderer) endpointIptablesChain(
policyNames []string,
profileIds []string,
name string,
policyPrefix PolicyChainNamePrefix,
profilePrefix ProfileChainNamePrefix,
endpointPrefix string,
failsafeChain string,
chainType endpointChainType,
adminUp bool,
allowAction Action,
dropEncap bool,
) *Chain {
rules := []Rule{}
chainName := EndpointChainName(endpointPrefix, name)
if !adminUp {
// Endpoint is admin-down, drop all traffic to/from it.
rules = append(rules, Rule{
Match: Match(),
Action: DropAction{},
Comment: "Endpoint admin disabled",
})
return &Chain{
Name: chainName,
Rules: rules,
}
}
if chainType != chainTypeUntracked {
// Tracked chain: install conntrack rules, which implement our stateful connections.
// This allows return traffic associated with a previously-permitted request.
rules = r.appendConntrackRules(rules, allowAction)
}
// First set up failsafes.
if failsafeChain != "" {
rules = append(rules, Rule{
Action: JumpAction{Target: failsafeChain},
})
}
// Start by ensuring that the accept mark bit is clear, policies set that bit to indicate
// that they accepted the packet.
rules = append(rules, Rule{
Action: ClearMarkAction{
Mark: r.IptablesMarkAccept,
},
})
if dropEncap {
rules = append(rules, Rule{
Match: Match().ProtocolNum(ProtoUDP).
DestPorts(uint16(r.Config.VXLANPort)),
Action: DropAction{},
Comment: "Drop VXLAN encapped packets originating in pods",
})
rules = append(rules, Rule{
Match: Match().ProtocolNum(ProtoIPIP),
Action: DropAction{},
Comment: "Drop IPinIP encapped packets originating in pods",
})
}
if len(policyNames) > 0 {
// Clear the "pass" mark. If a policy sets that mark, we'll skip the rest of the policies and
// continue processing the profiles, if there are any.
rules = append(rules, Rule{
Comment: "Start of policies",
Action: ClearMarkAction{
Mark: r.IptablesMarkPass,
},
})
// Then, jump to each policy in turn.
for _, polID := range policyNames {
polChainName := PolicyChainName(
policyPrefix,
&proto.PolicyID{Name: polID},
)
// If a previous policy didn't set the "pass" mark, jump to the policy.
rules = append(rules, Rule{
Match: Match().MarkClear(r.IptablesMarkPass),
Action: JumpAction{Target: polChainName},
})
// If policy marked packet as accepted, it returns, setting the accept
// mark bit.
if chainType == chainTypeUntracked {
// For an untracked policy, map allow to "NOTRACK and ALLOW".
rules = append(rules, Rule{
Match: Match().MarkSingleBitSet(r.IptablesMarkAccept),
Action: NoTrackAction{},
})
}
// If accept bit is set, return from this chain. We don't immediately
// accept because there may be other policy still to apply.
rules = append(rules, Rule{
Match: Match().MarkSingleBitSet(r.IptablesMarkAccept),
Action: ReturnAction{},
Comment: "Return if policy accepted",
})
}
if chainType == chainTypeNormal || chainType == chainTypeForward {
// When rendering normal and forward rules, if no policy marked the packet as "pass", drop the
// packet.
//
// For untracked and pre-DNAT rules, we don't do that because there may be
// normal rules still to be applied to the packet in the filter table.
rules = append(rules, Rule{
Match: Match().MarkClear(r.IptablesMarkPass),
Action: DropAction{},
Comment: "Drop if no policies passed packet",
})
}
} else if chainType == chainTypeForward {
// Forwarded traffic is allowed when there are no policies with
// applyOnForward that apply to this endpoint (and in this direction).
rules = append(rules, Rule{
Action: SetMarkAction{Mark: r.IptablesMarkAccept},
Comment: "Allow forwarded traffic by default",
})
rules = append(rules, Rule{
Action: ReturnAction{},
Comment: "Return for accepted forward traffic",
})
}
if chainType == chainTypeNormal {
// Then, jump to each profile in turn.
for _, profileID := range profileIds {
profChainName := ProfileChainName(profilePrefix, &proto.ProfileID{Name: profileID})
rules = append(rules,
Rule{Action: JumpAction{Target: profChainName}},
// If policy marked packet as accepted, it returns, setting the
// accept mark bit. If that is set, return from this chain.
Rule{
Match: Match().MarkSingleBitSet(r.IptablesMarkAccept),
Action: ReturnAction{},
Comment: "Return if profile accepted",
})
}
// When rendering normal rules, if no profile marked the packet as accepted, drop
// the packet.
//
// For untracked rules, we don't do that because there may be tracked rules
// still to be applied to the packet in the filter table.
rules = append(rules, Rule{
Match: Match(),
Action: DropAction{},
Comment: "Drop if no profiles matched",
})
}
return &Chain{
Name: chainName,
Rules: rules,
}
}
func (r *DefaultRuleRenderer) appendConntrackRules(rules []Rule, allowAction Action) []Rule {
// Allow return packets for established connections.
if allowAction != (AcceptAction{}) {
// If we've been asked to return instead of accept the packet immediately,
// make sure we flag the packet as allowed.
rules = append(rules,
Rule{
Match: Match().ConntrackState("RELATED,ESTABLISHED"),
Action: SetMarkAction{Mark: r.IptablesMarkAccept},
},
)
}
rules = append(rules,
Rule{
Match: Match().ConntrackState("RELATED,ESTABLISHED"),
Action: allowAction,
},
)
if !r.Config.DisableConntrackInvalid {
// Drop packets that aren't either a valid handshake or part of an established
// connection.
rules = append(rules, Rule{
Match: Match().ConntrackState("INVALID"),
Action: DropAction{},
})
}
return rules
}
func EndpointChainName(prefix string, ifaceName string) string {
return hashutils.GetLengthLimitedID(
prefix,
ifaceName,
MaxChainNameLength,
)
}