README
¶
netneslink 
NESlink is go package that allows for interaction with netlink. NESlink is simply a quality of life wrapper around these great netlink and netns packages. Not all the functionality of these packages remains in NESlink, but the interactions that are included are better suited to the NES platform implementation.
The main objective of this package is to make link interaction easier when dealing with many links across many network namespaces. This includes safe parallel operations in multiple namespaces.
Usage
At the core of this package are the Do functions, one for network namespaces, the other for links. These allow for low-code, go routine safe interaction with both links and namespaces (and links in namespaces).
Namespace Interaction
Any interaction with a netns should be done via a call to NsDo. As an example, to list the links in a network namespace, you would simply need to provide NsDo with a NsProvider for the target namespace, and the NsAction for listing links. So if there was a network namespace called example, then the following snippet would perform the action safely:
links := make([]netlink.Link, 0)
err, ok := neslink.NsDo(neslink.NPName("example"), neslink.NALinks(&links))
if err != nil || !ok {
...
💡 Any number of
NSActionscan be provided to a singleNsDocall, and they will be executed in order.
Here err would contain any error that occurred either in switching namespaces or within the function. However, ok will only be true if the network namespace was successfully returned to the original netns prior to running the function.
A new netns can be created similarly by specifying with the NPNew() or NPNewNamed(...) provider. The actions set can simply be left blank if you wish to only create the netns and not interact with it.
Custom NsActions can be easily created too, see this example.
Link Interaction
To manage links, any operation should be a LinkAction set in a call to LinkDo. Much like NsDo, LinkDo will execute a set of functions in a given netns, but applied to a specific link found via a LinkProvider. As an example, the below snippet will create a new bridge called br0 in a pre-existing named netns called example, then set its MAC address to 12:23:34:45:56:67 and set its state to UP:
if err, ok := neslink.LinkDo(
neslink.NPName("example"),
neslink.LPNewBridge("br0"),
neslink.LASetHw("12:23:34:45:56:67"),
neslink.LASetUp(),
); err != nil || !ok {
...
📝 Setting a link's netns is not a
LinkActionbut instead aNsAction, since after moving the link to another netns, the netns of the LinkDo goroutine should also be changed to the netns to complete any further actions on the link.
Via the LinkProviders, new links can be created, or already created links can be obtained via their name, index, or alias.
NEScript Integration
Using this package, NEScripts can be executed on any specific netns, making it easy to specify custom actions to execute via the NsAction system.
Other Notes
- Both
XXDofunctions have aMustXXDovariant that will still return errors, but if the function can not successfully revert to the original netns, will cause a panic.
Motivation
Whilst the 2 packages referenced at the top of this doc for netlink and netns provide all this functionality and more, they are still somewhat low-level packages. This can result in programs that use them extensively needing a lot of wrapper code to make the provided functionality easier and safer to use. This package is that wrapper code.
🚧 WIP
- Address inline TODOs
- Add tests
- Run tests via actions
Documentation
¶
Index ¶
- func DeleteNamedNs(name string) error
- func LinkDo(nsP NsProvider, lP LinkProvider, actions ...LinkAction) (error, bool)
- func MustLinkDo(nsP NsProvider, lP LinkProvider, actions ...LinkAction) error
- func MustNsDo(nsP NsProvider, actions ...NsAction) error
- func NsDo(nsP NsProvider, actions ...NsAction) (error, bool)
- type LinkAction
- func LAAddAddr(cidr string) LinkAction
- func LADelAddr(cidr string) LinkAction
- func LADelete() LinkAction
- func LAGeneric(name string, function func(netlink.Link) error) LinkAction
- func LASetAlias(alias string) LinkAction
- func LASetDown() LinkAction
- func LASetHw(addr string) LinkAction
- func LASetName(name string) LinkAction
- func LASetPromiscOff() LinkAction
- func LASetPromiscOn() LinkAction
- func LASetUp() LinkAction
- type LinkProvider
- func LPAlias(alias string) LinkProvider
- func LPIndex(index int) LinkProvider
- func LPName(name string) LinkProvider
- func LPNewBridge(name string) LinkProvider
- func LPNewDummy(name string) LinkProvider
- func LPNewGRETap(name, localIP, remoteIP string) LinkProvider
- func LPNewVeth(name, peerName string) LinkProvider
- func LPNewVxlan(name, localIP, groupIP string, id, port int) LinkProvider
- func LPNewWireguard(name string) LinkProvider
- type NsAction
- func NAExecNescript(script nescript.Script, subcommand []string, process *nescript.Process) NsAction
- func NAGeneric(name string, function func() error) NsAction
- func NAGetLink(provider LinkProvider, link *netlink.Link) NsAction
- func NAGetNsFd(nsfd *NsFd) NsAction
- func NALinks(links *[]netlink.Link) NsAction
- func NASetLinkNs(lP LinkProvider, nsP NsProvider) NsAction
- type NsFd
- type NsProvider
- func NPCurrent() NsProvider
- func NPDocker(containerID string) NsProvider
- func NPName(name string) NsProvider
- func NPNew() NsProvider
- func NPNewNamed(name string) NsProvider
- func NPNow() NsProvider
- func NPPath(path string) NsProvider
- func NPProcess(pid int) NsProvider
- func NPThread(pid, tid int) NsProvider
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func DeleteNamedNs ¶
DeleteNamedNs literally just called the delete named from the netlink package, but is here just incase of a use case where there is no other reason to directly import that package.
func LinkDo ¶
func LinkDo(nsP NsProvider, lP LinkProvider, actions ...LinkAction) (error, bool)
LinkDo runs a set of link actions on a link that is obtained from the given LinkProvider. The link provider is called and the actions are performed in the namespace obtained by the NsProvider, thus this can be used to manage links in any namespace. The actions are perfromed in the given namespace via NsDo, so the returned outputs are much the same as with NsDo.
func MustLinkDo ¶
func MustLinkDo(nsP NsProvider, lP LinkProvider, actions ...LinkAction) error
MustLinkDo performs a normal LinkDo, however if it fails to revert back to the origin netns, then this will trigger a panic. Any other errors are returned as normal.
func MustNsDo ¶
func MustNsDo(nsP NsProvider, actions ...NsAction) error
MustNsDo performs a normal NsDo, however if it fails to revert back to the origin netns, then this will trigger a panic. Any other errors are returned as normal.
func NsDo ¶
func NsDo(nsP NsProvider, actions ...NsAction) (error, bool)
NsDo executes a given function in a specified network namespace. It does so in a separate OS thread in order to allow the rest of the program to continue on the current network namespace. Returned is the error (if any occurred) and a bool, that if false, shows that the function did not successfully return the netns back to the origin, a potentially critical error.
Types ¶
type LinkAction ¶
type LinkAction struct {
// contains filtered or unexported fields
}
LinkAction is a singular operation that can be performed on a generic netlink link. Actions have a name as to identify individual actions when passed as a set to a LinkDo call, providing more contextual errors. They also have a function that take a link as a parameter. When called, the function will perform the operation on the provided link, returning an error if any occurred. These do support being executed outside of LinkDo calls, but using LinkDo is still recommended.
func LAAddAddr ¶
func LAAddAddr(cidr string) LinkAction
func LADelAddr ¶
func LADelAddr(cidr string) LinkAction
func LADelete ¶
func LADelete() LinkAction
LADelete will simply delete the link when the action is executed. For obvious reasons this should be at the end of any LinkDo call (since the link will be deleted, further actions will error).
func LAGeneric ¶
func LAGeneric(name string, function func(netlink.Link) error) LinkAction
LAGeneric allows for a custom LinkAction to be created and then used in a LinkDo call.
func LASetAlias ¶
func LASetAlias(alias string) LinkAction
func LASetDown ¶
func LASetDown() LinkAction
func LASetHw ¶
func LASetHw(addr string) LinkAction
func LASetName ¶
func LASetName(name string) LinkAction
func LASetPromiscOff ¶
func LASetPromiscOff() LinkAction
func LASetPromiscOn ¶
func LASetPromiscOn() LinkAction
func LASetUp ¶
func LASetUp() LinkAction
func (LinkAction) ActionName ¶
func (la LinkAction) ActionName() string
ActionName returns the name associated with the given link action.
type LinkProvider ¶
func LPAlias ¶
func LPAlias(alias string) LinkProvider
LPAlias creates a link provider that when called, will provide the pre-existing link with the given alias (in the namespace this is called in). If no matches are found, an error is returned.
func LPIndex ¶
func LPIndex(index int) LinkProvider
LPIndex creates a link provider that when called, will provide the pre-existing link with the given index (in the namespace this is called in). If no matches are found, an error is returned.
func LPName ¶
func LPName(name string) LinkProvider
LPName creates a link provider that when called, will provide the pre-existing link with the given name (in the namespace this is called in). If no matches are found, an error is returned.
func LPNewBridge ¶
func LPNewBridge(name string) LinkProvider
LPNewBridge creates a link provider that when called, will create a new bridge with the given name and then provides the newly created bridge.
func LPNewDummy ¶
func LPNewDummy(name string) LinkProvider
LPNewDummy creates a link provider that when called, will create a new dummy link with the given name and returns it, provided no errors occur.
func LPNewGRETap ¶
func LPNewGRETap(name, localIP, remoteIP string) LinkProvider
LPNewGRETap creates a link provider that when called, creates a new gretap device with the given name, local IP, and remoteIP.
func LPNewVeth ¶
func LPNewVeth(name, peerName string) LinkProvider
LPNewVeth creates a link provider that when called, will create a new veth pair and return the link. The names for both the new interfaces (main link and peer) should be provided. Only the main link is actually then provided by the LinkProvider. To get the peer, LAName with the peer's name should suffice. Any errors in creating/finding the veth pair are also returned.
func LPNewVxlan ¶
func LPNewVxlan(name, localIP, groupIP string, id, port int) LinkProvider
LPNewVxlan creates a link provider that when called, will create a new vxlan link with the given configuration and returns it.
func LPNewWireguard ¶
func LPNewWireguard(name string) LinkProvider
LPNewWireguard creates a link provider that when called, will create a new wireguard link with the given name and returns it, provided no errors occur. Further setup of this link should be done in custom LinkDos withwireguard specifc code.
type NsAction ¶
type NsAction struct {
// contains filtered or unexported fields
}
NsAction represents an action that should be executed in a namespace via NsDo. The action should have a relevant name as to give context to errors (as multiple actions are executed in a single NsDo call). Also the action itself should be a function that takes no parameters and returns an error (or nil in the event of success).
func NAExecNescript ¶
func NAExecNescript(script nescript.Script, subcommand []string, process *nescript.Process) NsAction
NAExecNescript will execute a NEScript in the netns it is called in, most likely the netns of the wrapping NsDo. This opens up extensive custom options. Provided should be the already compiled NEScript, a subcommand to use for the script such as ["sh" "-c"] (or nil to use the nescript package's deafult), and a nescript.Process for the resulting process to be stored in.
func NAGeneric ¶
NAGeneric allows for a custom action (function) to be performed in a given network namespace. A name should be given to describe the custom function in a couple of words to give context to NsDo errors.
func NAGetLink ¶
func NAGetLink(provider LinkProvider, link *netlink.Link) NsAction
NAGetLink gets a specific link from the given link provider when the action is called. The result is stored within the given link parameter. An error is returned if any occurred.
func NAGetNsFd ¶
NAGetNsFd provides an open file descriptor for the network namespace it is called in. This fd is separate from that of the one in the enclosing NsDo, so it is up to the user to close the fd when it is no longer needed.
func NALinks ¶
ListLinks returns a list of all the links in the namespace obtained via the given provider. Any errors are returned and a boolean to express if the the network namespace has returned back to the origin successfully.
func NASetLinkNs ¶
func NASetLinkNs(lP LinkProvider, nsP NsProvider) NsAction
NASetLinkNs moves a link provided by the given link provider to the namespace provided by the ns provider. The link itself should br present in the namespace in which the wrapping NsDo is set to execute in.
type NsFd ¶
type NsFd int
NsFd is a file descriptor referencing a network namespace. This can be used to interact and mange the netns.
func (*NsFd) Close ¶
Close effectively closes the reference to the netns, thus after calling the file descriptor should not be used again. This is handled already by the Do functions in this package, so is only needed to be used when manually managaging netns handles.
type NsProvider ¶
NsProvider is a function that retruns a network namespace (netns) handle (file descriptor) when it is called. If the provider fails to correctly obtain the netns, an error is returned.
func NPCurrent ¶
func NPCurrent() NsProvider
NPCurrent returns a netns provider that will return the current netns fd as of the time when the provider itself is called.
func NPDocker ¶
func NPDocker(containerID string) NsProvider
NPDocker returns a netns provider that when called will return the netns fd associated with a given docker container.
func NPName ¶
func NPName(name string) NsProvider
NPName returns a netns provider that when called will return the netns fd associated with the given name.
func NPNew ¶
func NPNew() NsProvider
NPNew returns a netns provider that when called will create a new unnamed netns (in turn switching to it) and returns the fd of the newly created ns.
func NPNewNamed ¶
func NPNewNamed(name string) NsProvider
NPNewNamed returns a netns provider that when called will create a new named netns (in turn switching to it) and returns the fd of the newly created ns.
func NPNow ¶
func NPNow() NsProvider
NPNow returns a netns provider that simply provides the netns fd that was found at the time that the provider itself was generated (the time that this function is called).
func NPPath ¶
func NPPath(path string) NsProvider
NPPath returns a netns provider that when called will return the netns fd associated with the given file path.
func NPProcess ¶
func NPProcess(pid int) NsProvider
NPProcess returns a netns provider that when called will return the netns fd associated with the given process.
func NPThread ¶
func NPThread(pid, tid int) NsProvider
NPThread returns a netns provider that when called will return the netns fd associated with the given thread.
Source Files
Directories