diff options
Diffstat (limited to 'pkg/tcpip/stack/iptables.go')
| -rw-r--r-- | pkg/tcpip/stack/iptables.go | 91 |
1 files changed, 38 insertions, 53 deletions
diff --git a/pkg/tcpip/stack/iptables.go b/pkg/tcpip/stack/iptables.go index 443423b3c..4e9b404c8 100644 --- a/pkg/tcpip/stack/iptables.go +++ b/pkg/tcpip/stack/iptables.go @@ -16,7 +16,6 @@ package stack import ( "fmt" - "strings" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/header" @@ -44,11 +43,11 @@ const HookUnset = -1 // DefaultTables returns a default set of tables. Each chain is set to accept // all packets. -func DefaultTables() IPTables { +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{ + return &IPTables{ + tables: map[string]Table{ TablenameNat: Table{ Rules: []Rule{ Rule{Target: AcceptTarget{}}, @@ -107,7 +106,7 @@ func DefaultTables() IPTables { UserChains: map[string]int{}, }, }, - Priorities: map[Hook][]string{ + priorities: map[Hook][]string{ Input: []string{TablenameNat, TablenameFilter}, Prerouting: []string{TablenameMangle, TablenameNat}, Output: []string{TablenameMangle, TablenameNat, TablenameFilter}, @@ -159,6 +158,36 @@ func EmptyNatTable() Table { } } +// GetTable returns table by name. +func (it *IPTables) GetTable(name string) (Table, bool) { + it.mu.RLock() + defer it.mu.RUnlock() + t, ok := it.tables[name] + return t, ok +} + +// ReplaceTable replaces or inserts table by name. +func (it *IPTables) ReplaceTable(name string, table Table) { + it.mu.Lock() + defer it.mu.Unlock() + it.tables[name] = table +} + +// ModifyTables acquires write-lock and calls fn with internal name-to-table +// map. This function can be used to update multiple tables atomically. +func (it *IPTables) ModifyTables(fn func(map[string]Table)) { + it.mu.Lock() + defer it.mu.Unlock() + fn(it.tables) +} + +// GetPriorities returns slice of priorities associated with hook. +func (it *IPTables) GetPriorities(hook Hook) []string { + it.mu.RLock() + defer it.mu.RUnlock() + return it.priorities[hook] +} + // A chainVerdict is what a table decides should be done with a packet. type chainVerdict int @@ -185,8 +214,8 @@ func (it *IPTables) Check(hook Hook, pkt *PacketBuffer, gso *GSO, r *Route, addr it.connections.HandlePacket(pkt, hook, gso, r) // Go through each table containing the hook. - for _, tablename := range it.Priorities[hook] { - table := it.Tables[tablename] + for _, tablename := range it.GetPriorities(hook) { + table, _ := it.GetTable(tablename) ruleIdx := table.BuiltinChains[hook] switch verdict := it.checkChain(hook, pkt, table, ruleIdx, gso, r, address, nicName); verdict { // If the table returns Accept, move on to the next table. @@ -314,7 +343,7 @@ func (it *IPTables) checkRule(hook Hook, pkt *PacketBuffer, table Table, ruleIdx } // Check whether the packet matches the IP header filter. - if !filterMatch(rule.Filter, header.IPv4(pkt.NetworkHeader), hook, nicName) { + if !rule.Filter.match(header.IPv4(pkt.NetworkHeader), hook, nicName) { // Continue on to the next rule. return RuleJump, ruleIdx + 1 } @@ -322,7 +351,7 @@ func (it *IPTables) checkRule(hook Hook, pkt *PacketBuffer, table Table, ruleIdx // Go through each rule matcher. If they all match, run // the rule target. for _, matcher := range rule.Matchers { - matches, hotdrop := matcher.Match(hook, *pkt, "") + matches, hotdrop := matcher.Match(hook, pkt, "") if hotdrop { return RuleDrop, 0 } @@ -335,47 +364,3 @@ func (it *IPTables) checkRule(hook Hook, pkt *PacketBuffer, table Table, ruleIdx // All the matchers matched, so run the target. return rule.Target.Action(pkt, &it.connections, hook, gso, r, address) } - -func filterMatch(filter IPHeaderFilter, hdr header.IPv4, hook Hook, nicName string) bool { - // TODO(gvisor.dev/issue/170): Support other fields of the filter. - // Check the transport protocol. - if filter.Protocol != 0 && filter.Protocol != hdr.TransportProtocol() { - return false - } - - // Check the destination IP. - dest := hdr.DestinationAddress() - matches := true - for i := range filter.Dst { - if dest[i]&filter.DstMask[i] != filter.Dst[i] { - matches = false - break - } - } - if matches == filter.DstInvert { - return false - } - - // Check the output interface. - // TODO(gvisor.dev/issue/170): Add the check for FORWARD and POSTROUTING - // hooks after supported. - if hook == Output { - n := len(filter.OutputInterface) - if n == 0 { - return true - } - - // If the interface name ends with '+', any interface which begins - // with the name should be matched. - ifName := filter.OutputInterface - matches = true - if strings.HasSuffix(ifName, "+") { - matches = strings.HasPrefix(nicName, ifName[:n-1]) - } else { - matches = nicName == ifName - } - return filter.OutputInterfaceInvert != matches - } - - return true -} |