diff options
Diffstat (limited to 'pkg/tcpip/iptables')
-rw-r--r-- | pkg/tcpip/iptables/BUILD | 5 | ||||
-rw-r--r-- | pkg/tcpip/iptables/iptables.go | 120 | ||||
-rw-r--r-- | pkg/tcpip/iptables/targets.go | 16 | ||||
-rw-r--r-- | pkg/tcpip/iptables/types.go | 49 |
4 files changed, 118 insertions, 72 deletions
diff --git a/pkg/tcpip/iptables/BUILD b/pkg/tcpip/iptables/BUILD index cc5f531e2..64769c333 100644 --- a/pkg/tcpip/iptables/BUILD +++ b/pkg/tcpip/iptables/BUILD @@ -11,5 +11,8 @@ go_library( ], importpath = "gvisor.dev/gvisor/pkg/tcpip/iptables", visibility = ["//visibility:public"], - deps = ["//pkg/tcpip/buffer"], + deps = [ + "//pkg/log", + "//pkg/tcpip/buffer", + ], ) diff --git a/pkg/tcpip/iptables/iptables.go b/pkg/tcpip/iptables/iptables.go index 68c68d4aa..647970133 100644 --- a/pkg/tcpip/iptables/iptables.go +++ b/pkg/tcpip/iptables/iptables.go @@ -16,66 +16,114 @@ // tool. package iptables +// Table names. const ( - tablenameNat = "nat" - tablenameMangle = "mangle" + TablenameNat = "nat" + TablenameMangle = "mangle" + TablenameFilter = "filter" ) // Chain names as defined by net/ipv4/netfilter/ip_tables.c. const ( - chainNamePrerouting = "PREROUTING" - chainNameInput = "INPUT" - chainNameForward = "FORWARD" - chainNameOutput = "OUTPUT" - chainNamePostrouting = "POSTROUTING" + ChainNamePrerouting = "PREROUTING" + ChainNameInput = "INPUT" + ChainNameForward = "FORWARD" + ChainNameOutput = "OUTPUT" + ChainNamePostrouting = "POSTROUTING" ) +// HookUnset indicates that there is no hook set for an entrypoint or +// underflow. +const HookUnset = -1 + // DefaultTables returns a default set of tables. Each chain is set to accept // all packets. func DefaultTables() IPTables { + // TODO(gvisor.dev/issue/170): We may be able to swap out some strings for + // iotas. return IPTables{ Tables: map[string]Table{ - tablenameNat: Table{ - BuiltinChains: map[Hook]Chain{ - Prerouting: unconditionalAcceptChain(chainNamePrerouting), - Input: unconditionalAcceptChain(chainNameInput), - Output: unconditionalAcceptChain(chainNameOutput), - Postrouting: unconditionalAcceptChain(chainNamePostrouting), + TablenameNat: Table{ + Rules: []Rule{ + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: ErrorTarget{}}, + }, + BuiltinChains: map[Hook]int{ + Prerouting: 0, + Input: 1, + Output: 2, + Postrouting: 3, }, - DefaultTargets: map[Hook]Target{ - Prerouting: UnconditionalAcceptTarget{}, - Input: UnconditionalAcceptTarget{}, - Output: UnconditionalAcceptTarget{}, - Postrouting: UnconditionalAcceptTarget{}, + Underflows: map[Hook]int{ + Prerouting: 0, + Input: 1, + Output: 2, + Postrouting: 3, }, - UserChains: map[string]Chain{}, + UserChains: map[string]int{}, }, - tablenameMangle: Table{ - BuiltinChains: map[Hook]Chain{ - Prerouting: unconditionalAcceptChain(chainNamePrerouting), - Output: unconditionalAcceptChain(chainNameOutput), + TablenameMangle: Table{ + Rules: []Rule{ + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: ErrorTarget{}}, + }, + BuiltinChains: map[Hook]int{ + Prerouting: 0, + Output: 1, }, - DefaultTargets: map[Hook]Target{ - Prerouting: UnconditionalAcceptTarget{}, - Output: UnconditionalAcceptTarget{}, + Underflows: map[Hook]int{ + Prerouting: 0, + Output: 1, }, - UserChains: map[string]Chain{}, + UserChains: map[string]int{}, + }, + TablenameFilter: Table{ + Rules: []Rule{ + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: UnconditionalAcceptTarget{}}, + Rule{Target: ErrorTarget{}}, + }, + BuiltinChains: map[Hook]int{ + Input: 0, + Forward: 1, + Output: 2, + }, + Underflows: map[Hook]int{ + Input: 0, + Forward: 1, + Output: 2, + }, + UserChains: map[string]int{}, }, }, Priorities: map[Hook][]string{ - Prerouting: []string{tablenameMangle, tablenameNat}, - Output: []string{tablenameMangle, tablenameNat}, + Input: []string{TablenameNat, TablenameFilter}, + Prerouting: []string{TablenameMangle, TablenameNat}, + Output: []string{TablenameMangle, TablenameNat, TablenameFilter}, }, } } -func unconditionalAcceptChain(name string) Chain { - return Chain{ - Name: name, - Rules: []Rule{ - Rule{ - Target: UnconditionalAcceptTarget{}, - }, +// EmptyFilterTable returns a Table with no rules and the filter table chains +// mapped to HookUnset. +func EmptyFilterTable() Table { + return Table{ + Rules: []Rule{}, + BuiltinChains: map[Hook]int{ + Input: HookUnset, + Forward: HookUnset, + Output: HookUnset, + }, + Underflows: map[Hook]int{ + Input: HookUnset, + Forward: HookUnset, + Output: HookUnset, }, + UserChains: map[string]int{}, } } diff --git a/pkg/tcpip/iptables/targets.go b/pkg/tcpip/iptables/targets.go index 19a7f77e3..b94a4c941 100644 --- a/pkg/tcpip/iptables/targets.go +++ b/pkg/tcpip/iptables/targets.go @@ -16,7 +16,10 @@ package iptables -import "gvisor.dev/gvisor/pkg/tcpip/buffer" +import ( + "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/tcpip/buffer" +) // UnconditionalAcceptTarget accepts all packets. type UnconditionalAcceptTarget struct{} @@ -33,3 +36,14 @@ type UnconditionalDropTarget struct{} func (UnconditionalDropTarget) Action(packet buffer.VectorisedView) (Verdict, string) { return Drop, "" } + +// ErrorTarget logs an error and drops the packet. It represents a target that +// should be unreachable. +type ErrorTarget struct{} + +// Action implements Target.Action. +func (ErrorTarget) Action(packet buffer.VectorisedView) (Verdict, string) { + log.Warningf("ErrorTarget triggered.") + return Drop, "" + +} diff --git a/pkg/tcpip/iptables/types.go b/pkg/tcpip/iptables/types.go index 42a79ef9f..540f8c0b4 100644 --- a/pkg/tcpip/iptables/types.go +++ b/pkg/tcpip/iptables/types.go @@ -61,9 +61,12 @@ const ( type Verdict int const ( + // Invalid indicates an unkonwn or erroneous verdict. + Invalid Verdict = iota + // Accept indicates the packet should continue traversing netstack as // normal. - Accept Verdict = iota + Accept // Drop inicates the packet should be dropped, stopping traversing // netstack. @@ -104,29 +107,22 @@ type IPTables struct { Priorities map[Hook][]string } -// A Table defines a set of chains and hooks into the network stack. The -// currently supported tables are: -// * nat -// * mangle +// A Table defines a set of chains and hooks into the network stack. It is +// really just a list of rules with some metadata for entrypoints and such. type Table struct { - // BuiltinChains holds the un-deletable chains built into netstack. If - // a hook isn't present in the map, this table doesn't utilize that - // hook. - BuiltinChains map[Hook]Chain + // Rules holds the rules that make up the table. + Rules []Rule - // DefaultTargets holds a target for each hook that will be executed if - // chain traversal doesn't yield a verdict. - DefaultTargets map[Hook]Target + // BuiltinChains maps builtin chains to their entrypoint rule in Rules. + BuiltinChains map[Hook]int + + // Underflows maps builtin chains to their underflow rule in Rules + // (i.e. the rule to execute if the chain returns without a verdict). + Underflows map[Hook]int // UserChains holds user-defined chains for the keyed by name. Users // can give their chains arbitrary names. - UserChains map[string]Chain - - // Chains maps names to chains for both builtin and user-defined chains. - // Its entries point to Chains already either in BuiltinChains or - // UserChains, and its purpose is to make looking up tables by name - // fast. - Chains map[string]*Chain + UserChains map[string]int // Metadata holds information about the Table that is useful to users // of IPTables, but not to the netstack IPTables code itself. @@ -152,21 +148,6 @@ func (table *Table) SetMetadata(metadata interface{}) { table.metadata = metadata } -// A Chain defines a list of rules for packet processing. When a packet -// traverses a chain, it is checked against each rule until either a rule -// returns a verdict or the chain ends. -// -// By convention, builtin chains end with a rule that matches everything and -// returns either Accept or Drop. User-defined chains end with Return. These -// aren't strictly necessary here, but the iptables tool writes tables this way. -type Chain struct { - // Name is the chain name. - Name string - - // Rules is the list of rules to traverse. - Rules []Rule -} - // A Rule is a packet processing rule. It consists of two pieces. First it // contains zero or more matchers, each of which is a specification of which // packets this rule applies to. If there are no matchers in the rule, it |