|
| 1 | +package container |
| 2 | + |
| 3 | +import ( |
| 4 | + "errors" |
| 5 | + "fmt" |
| 6 | + |
| 7 | + "github.com/coreos/go-iptables/iptables" |
| 8 | + "github.com/vishvananda/netlink" |
| 9 | +) |
| 10 | + |
| 11 | +func getDefaultLink() (netlink.Link, error) { |
| 12 | + var link netlink.Link |
| 13 | + routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL) |
| 14 | + if err != nil { |
| 15 | + return link, err |
| 16 | + } |
| 17 | + dNet, _ := netlink.ParseAddr("0.0.0.0/0") |
| 18 | + for _, r := range routes { |
| 19 | + if r.Dst.Network() == dNet.IPNet.Network() { |
| 20 | + return netlink.LinkByIndex(r.LinkIndex) |
| 21 | + } |
| 22 | + } |
| 23 | + err = errors.New("did not find a default route") |
| 24 | + return link, err |
| 25 | +} |
| 26 | + |
| 27 | +func setForwarding(containerLink string, defaultLink string) error { |
| 28 | + table, err := iptables.New() |
| 29 | + if err != nil { |
| 30 | + return err |
| 31 | + } |
| 32 | + // masq |
| 33 | + err = table.Append("nat", "POSTROUTING", "-o", defaultLink, "-j", "MASQUERADE") |
| 34 | + if err != nil { |
| 35 | + return err |
| 36 | + } |
| 37 | + |
| 38 | + // forward |
| 39 | + err = table.Append("filter", "FORWARD", "-i", containerLink, "-o", defaultLink, "-j", "ACCEPT") |
| 40 | + if err != nil { |
| 41 | + return err |
| 42 | + } |
| 43 | + err = table.Append("filter", "FORWARD", "-i", containerLink, "-o", defaultLink, "-m", "state", "--state", "ESTABLISHED,RELATED", "-j", "ACCEPT") |
| 44 | + return err |
| 45 | +} |
| 46 | + |
| 47 | +func newBridge(id string, link netlink.Link) error { |
| 48 | + bAttrs := netlink.NewLinkAttrs() |
| 49 | + bAttrs.Name = "br-" + id |
| 50 | + br := &netlink.Bridge{LinkAttrs: bAttrs} |
| 51 | + err := netlink.LinkAdd(br) |
| 52 | + if err != nil { |
| 53 | + return err |
| 54 | + } |
| 55 | + err = netlink.LinkSetUp(br) |
| 56 | + if err != nil { |
| 57 | + return err |
| 58 | + } |
| 59 | + err = netlink.LinkSetMaster(link, br) |
| 60 | + return err |
| 61 | +} |
| 62 | + |
| 63 | +// func GetIP returns an available IP address for the container |
| 64 | +func (c *Container) GetIP() string { |
| 65 | + return "10.200.1.2/24" |
| 66 | +} |
| 67 | + |
| 68 | +func (c *Container) AttachNet(pid int) error { |
| 69 | + pName := "veth-" + c.Id |
| 70 | + lName := pName + "2" |
| 71 | + attr := netlink.LinkAttrs{Name: lName} |
| 72 | + link := netlink.NewVeth(attr) |
| 73 | + link.PeerName = pName |
| 74 | + err := netlink.LinkAdd(link) |
| 75 | + if err != nil { |
| 76 | + return err |
| 77 | + } |
| 78 | + peer, err := netlink.LinkByName(pName) |
| 79 | + if err != nil { |
| 80 | + return err |
| 81 | + } |
| 82 | + // TODO IP address lease management |
| 83 | + lAddr, err := netlink.ParseAddr("10.200.1.1/24") |
| 84 | + if err != nil { |
| 85 | + return err |
| 86 | + } |
| 87 | + err = netlink.AddrAdd(link, lAddr) |
| 88 | + if err != nil { |
| 89 | + return err |
| 90 | + } |
| 91 | + err = netlink.LinkSetUp(link) |
| 92 | + if err != nil { |
| 93 | + return err |
| 94 | + } |
| 95 | + err = netlink.LinkSetNsPid(peer, pid) |
| 96 | + if err != nil { |
| 97 | + return err |
| 98 | + } |
| 99 | + fmt.Println("DEBUG: setup veth and pushed peer into container netns") |
| 100 | + // peer gets configured within the namespace (addr, set up) |
| 101 | + |
| 102 | + // bridge for other containers to share the network. unlikely to use for awhile |
| 103 | + //newBridge(c.Id, link) |
| 104 | + // TODO teardown actions |
| 105 | + |
| 106 | + dLink, err := getDefaultLink() |
| 107 | + if err != nil { |
| 108 | + err = fmt.Errorf("failed to discover default network interface: %v", err) |
| 109 | + return err |
| 110 | + } |
| 111 | + dLinkName := dLink.Attrs().Name |
| 112 | + // TODO we should add routing to common bridge like docker does |
| 113 | + // then we can just setup iptables rules once |
| 114 | + |
| 115 | + // setup routing for the veth to the default interface |
| 116 | + err = setForwarding(lName, dLinkName) |
| 117 | + if err != nil { |
| 118 | + err = fmt.Errorf("failed to configure forwarding from host to container network: %v", err) |
| 119 | + return err |
| 120 | + } |
| 121 | + |
| 122 | + return err |
| 123 | +} |
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