-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Basic functionality works and is persistent
- Loading branch information
Showing
3 changed files
with
280 additions
and
39 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,84 @@ | ||
| package lsrv | ||
|
|
||
| import ( | ||
| "log" | ||
| "strconv" | ||
|
|
||
| "github.com/coreos/go-iptables/iptables" | ||
| ) | ||
|
|
||
| type IPTablesManager struct { | ||
| ipt *iptables.IPTables | ||
| } | ||
|
|
||
| func NewIPTablesManager() (*IPTablesManager, error) { | ||
| ipt, err := iptables.New() | ||
| if err != nil { | ||
| return nil, err | ||
| } else { | ||
| manager := new(IPTablesManager) | ||
| manager.ipt = ipt | ||
| return manager, nil | ||
| } | ||
| } | ||
|
|
||
| func (manager *IPTablesManager) Initialize() error { | ||
| ipt := manager.ipt | ||
|
|
||
| ipt.NewChain("nat", "LSRV") | ||
| ipt.AppendUnique("nat", "OUTPUT", "-jLSRV") | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| func (manager *IPTablesManager) AddRule(source_addr string, source_port uint16, | ||
| dest_addr string, dest_port uint16) error { | ||
|
|
||
| ipt := manager.ipt | ||
| rulespec := rule_for(source_addr, source_port, dest_addr, dest_port) | ||
|
|
||
| ipt.AppendUnique("nat", "LSRV", rulespec...) | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| func (manager *IPTablesManager) RemoveRule(source_addr string, source_port uint16, | ||
| dest_addr string, dest_port uint16) error { | ||
|
|
||
| ipt := manager.ipt | ||
| rulespec := rule_for(source_addr, source_port, dest_addr, dest_port) | ||
|
|
||
| return ipt.Delete("nat", "LSRV", rulespec...) | ||
| } | ||
|
|
||
| func (manager *IPTablesManager) Cleanup() error { | ||
| ipt := manager.ipt | ||
|
|
||
| chains, err := ipt.ListChains("nat") | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
|
||
| containsChain := false | ||
| for _, elem := range chains { | ||
| if elem == "LSRV" { | ||
| containsChain = true | ||
| } | ||
| } | ||
|
|
||
| if containsChain { | ||
| log.Println("Deleting chain LSRV") | ||
| ipt.Delete("nat", "OUTPUT", "-jLSRV") | ||
| ipt.ClearChain("nat", "LSRV") | ||
| ipt.DeleteChain("nat", "LSRV") | ||
| } | ||
| return nil | ||
| } | ||
|
|
||
| func rule_for(service_addr string, service_port uint16, | ||
| dest_addr string, dest_port uint16) []string { | ||
|
|
||
| return []string{"-p", "tcp", "-d", dest_addr, "--dport", | ||
| strconv.FormatUint(uint64(dest_port), 10), "-j", "DNAT", | ||
| "--to", service_addr + ":" + strconv.FormatUint(uint64(service_port), 10)} | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,146 @@ | ||
| package lsrv | ||
|
|
||
| import ( | ||
| "encoding/binary" | ||
| "encoding/json" | ||
| "fmt" | ||
| "io/ioutil" | ||
| "log" | ||
| "net" | ||
| "os" | ||
| ) | ||
|
|
||
| type ServiceManager struct { | ||
| // ip_allocator *IPAllocator | ||
| services map[string]ServiceEntry | ||
| state_path string | ||
| start_ip net.IP | ||
| ipt_man *IPTablesManager | ||
| } | ||
|
|
||
| type ServiceEntry struct { | ||
| ServiceAddress string | ||
| ServicePort uint16 | ||
|
|
||
| // The service will respond to the address/port below | ||
| DestAddress string | ||
| DestPort uint16 | ||
| } | ||
|
|
||
| func NewServiceManager(state_path string, start_ip net.IP) *ServiceManager { | ||
| manager := new(ServiceManager) | ||
| manager.state_path = state_path | ||
| manager.start_ip = start_ip | ||
|
|
||
| ipt_man, err := NewIPTablesManager() | ||
|
|
||
| if err != nil { | ||
| log.Fatal(err) | ||
| } | ||
|
|
||
| manager.ipt_man = ipt_man | ||
|
|
||
| if _, err := os.Stat(state_path); os.IsNotExist(err) { | ||
| manager.services = make(map[string]ServiceEntry) | ||
| } else { | ||
| manager.services = load(state_path) | ||
| } | ||
|
|
||
| manager.ipt_man.Cleanup() | ||
| manager.ipt_man.Initialize() | ||
|
|
||
| // TODO: What if start_ip has changed | ||
| for service_name, entry := range manager.services { | ||
| log.Printf("Loaded %s: %+v\n", service_name, entry) | ||
| manager.ipt_man.AddRule(entry.ServiceAddress, entry.ServicePort, entry.DestAddress, entry.DestPort) | ||
| } | ||
|
|
||
| return manager | ||
| } | ||
|
|
||
| func (manager *ServiceManager) Add(service_name string, service_address string, | ||
| service_port uint16, dest_port uint16) (ServiceEntry, error) { | ||
|
|
||
| entry, present := manager.services[service_name] | ||
| if present { | ||
| return entry, fmt.Errorf("Entry for service %s already exists", service_name) | ||
| } | ||
|
|
||
| entry = ServiceEntry{ | ||
| ServiceAddress: service_address, | ||
| ServicePort: service_port, | ||
| DestAddress: ipAdd(manager.start_ip, len(manager.services)).String(), | ||
| DestPort: dest_port, | ||
| } | ||
|
|
||
| manager.services[service_name] = entry | ||
| manager.serialize() | ||
| manager.ipt_man.AddRule(entry.ServiceAddress, entry.ServicePort, entry.DestAddress, entry.DestPort) | ||
| return entry, nil | ||
| } | ||
|
|
||
| func (manager *ServiceManager) Delete(service_name string) error { | ||
| entry, err := manager.GetServiceEntry(service_name) | ||
|
|
||
| if err != nil { | ||
| return err | ||
| } | ||
|
|
||
| err = manager.ipt_man.RemoveRule(entry.ServiceAddress, entry.ServicePort, | ||
| entry.DestAddress, entry.DestPort) | ||
|
|
||
| if err == nil { | ||
| delete(manager.services, service_name) | ||
| manager.serialize() | ||
| } | ||
|
|
||
| return err | ||
| } | ||
|
|
||
| func (manager *ServiceManager) List() []ServiceEntry { | ||
| tmp := make([]ServiceEntry, 0, len(manager.services)) | ||
|
|
||
| for _, value := range manager.services { | ||
| tmp = append(tmp, value) | ||
| } | ||
|
|
||
| return tmp | ||
| } | ||
|
|
||
| func (manager *ServiceManager) GetServiceEntry(service_name string) (ServiceEntry, error) { | ||
| entry, present := manager.services[service_name] | ||
|
|
||
| if present { | ||
| return entry, nil | ||
| } else { | ||
| return ServiceEntry{}, fmt.Errorf("Service not found") | ||
| } | ||
| } | ||
|
|
||
| func (manager *ServiceManager) serialize() { | ||
| services_json, _ := json.Marshal(manager.services) | ||
| // This is not safe. This file should be moved into place | ||
| err := ioutil.WriteFile(manager.state_path, services_json, 0644) | ||
| if err != nil { | ||
| log.Fatal(err) | ||
| } | ||
| } | ||
|
|
||
| func load(path string) map[string]ServiceEntry { | ||
| raw, err := ioutil.ReadFile(path) | ||
| if err != nil { | ||
| log.Fatal(err) | ||
| } | ||
|
|
||
| var services map[string]ServiceEntry | ||
| json.Unmarshal(raw, &services) | ||
|
|
||
| return services | ||
| } | ||
|
|
||
| func ipAdd(start net.IP, add int) net.IP { // IPv4 only | ||
| start = start.To4() | ||
| result := make(net.IP, 4) | ||
| binary.BigEndian.PutUint32(result, binary.BigEndian.Uint32(start)+uint32(add)) | ||
| return result | ||
| } |