This document was automatically generated from the exports/exports.go file

About the API

package main implements the main exported API to be used by other languages

Some notes:

Errors are returned as JSON c strings. The JSON type is defined in types/error/error.go Error. Free them using FreeString. Same is the case for other string types, you should also free them. The errors are always localized
Types are converted from the Go representation to C using JSON strings
Cookies are used for cancellation, just fancy contexts. Create a cookie using CookieNew, pass it to the function that needs one as the first argument. To cancel the function, call CookieCancel, passing in the same cookie as argument
Cookies must also be freed, by using the CookieDelete function if the cookie is no longer needed
The state machine is used to track the state of a client. It is mainly used for asking for certain data from the client, e.g. asking for profiles and locations. But a client may also wish to build upon this state machine to build the whole UI around it. The SetState and InState functions are useful for this

Functions

AddServer

Signature:

func AddServer(c C.uintptr_t, _type C.int, id *C.char, ot *C.longlong) *C.char

AddServer adds a server to the eduvpn-common server list c is the cookie that is used for cancellation. Create a cookie first with CookieNew. This same cookie is also used for replying to state transitions.

_type is the type of server that needs to be added. This type is defined in types/server/server.go Type

id is the identifier of the string:

In case of secure internet: The organization ID
In case of custom server: The base URL
In case of institute access: The base URL

ni stands for non-interactive. If non-zero, any state transitions will not be run.

This ot flag is useful for preprovisioned servers; set this to non-null to non-interactively add a server. This flag represents the Unix time OAuth was last triggered, if the server needs to be added non-interactively but there is no token structure, set this to zero (integer) or the current Unix time. This value will be overwritten once OAuth is triggered.

If the server cannot be added it returns the error as types/error/error.go Error. Note that the server is removed when an error has occured

The following state callbacks are mandatory to handle:

OAUTH_STARTED: This indicates that the OAuth procedure has been started, it returns the URL as the data. The client should open the webbrowser with this URL and continue the authorization process. Note: For mobile platforms this returns a Cookie and data (json: {"cookie": x, "data": url}). This url should also be opened in the browser like desktop platforms. But these platforms also need to reply to the library to give back the full authorization code URI with CookieReply(x, uri). E.g. CookieReply(x, "/callback?code=...&state=...&iss=...") this is the path of the request that the apps get back when the user clicks approve. For this, apps need to register an app url or sorts. For the valid values for app URLs, see the redirect URIs for mobile platforms here https://git.sr.ht/~fkooman/vpn-user-portal/tree/v3/item/src/OAuth/VpnClientDb.php

Example Input (3=custom server): AddServer(mycookie, 3, "https://demo.eduvpn.nl", 0)

Example Output:

{
  "message": {
    "en": "failed to add server"
  },
  "misc": false
}

CalculateGateway

Signature:

func CalculateGateway(subnet *C.char) (*C.char, *C.char)

CalculateGateway calculates the gateway for a subnet, it can take IPv4 or IPv6 networks with CIDR notation as inputs and returns the gateway address.

This is useful to pass to StartFailover. It returns an error if it fails to calculate a gateway. The function is implemented according to: the eduVPN docs.

Example Input: CalculateGateway("10.10.0.5/24")

Example Output: "10.10.0.1", null

Cleanup

Signature:

func Cleanup(c C.uintptr_t) *C.char

Cleanup sends a /disconnect to cleanup the connection. Additionally, if ProxyGuard is active it cancels the running process

This MUST be called when disconnecting, see the eduVPN docs. c is the Cookie that needs to be passed. Create a new Cookie using CookieNew.

If it was unsuccessful, it returns an error.

Example Input: Cleanup(myCookie)

Example Output:

{
  "message": {
    "en": "cleanup was not successful"
  },
  "misc": false
}

CookieCancel

Signature:

func CookieCancel(c C.uintptr_t) *C.char

CookieCancel cancels the cookie.

This means that functions which take this as first argument, return if they're still running. The error cause is always context.Canceled for that cancelled function: see the Go docs.

This CookieCancel function can also return an error if cancelling was unsuccessful. Example Input: CookieCancel(myCookie)

Example Output: null

CookieDelete

Signature:

func CookieDelete(c C.uintptr_t) *C.char

CookieDelete deletes the cookie by cancelling it and deleting the underlying cgo handle.

This function MUST be called when the cookie that is created using CookieNew is no longer needed. Example Input: CookieDelete(myCookie)

Example Output: null

CookieNew

Signature:

func CookieNew() C.uintptr_t

CookieNew creates a new cookie and returns it.

This value should not be parsed or converted somehow by the client. This value is simply to pass back to the Go library. This value has two purposes:

Cancel a long running function
Send a reply to a state transition (ASK_PROFILE and ASK_LOCATION)

Example Input: CookieNew()

Example Output: 5

CookieReply

Signature:

func CookieReply(c C.uintptr_t, data *C.char) *C.char

CookieReply replies to a state transition using the cookie.

c is the Cookie
data is the data to send, e.g. a profile ID

Example Input: CookieReply(myCookie, "split-tunnel-profile")

Example Output: null

CurrentServer

Signature:

func CurrentServer() (*C.char, *C.char)

CurrentServer gets the current server from eduvpn-common

In eduvpn-common, a server is marked as 'current' if you have gotten a VPN configuration for it

It returns the server as JSON, defined in types/server/server.go Current.

If there is no current server or some other, e.g. there is no current state, an error is returned with a nil string.

Example Input: CurrentServer()

Example Output:

{
  "institute_access_server": {
    "display_name": {
      "en": "Demo"
    },
    "identifier": "https://demo.eduvpn.nl/",
    "profiles": {
      "map": {
        "internet": {
          "display_name": {
            "en": "Internet"
          },
          "supported_protocols": [
            1,
            2
          ]
        },
        "internet-split": {
          "display_name": {
            "en": "No rfc1918 routes"
          },
          "supported_protocols": [
            1,
            2
          ]
        }
      },
      "current": "internet"
    },
    "support_contacts": [
      "mailto:eduvpn@surf.nl"
    ],
    "delisted": false
  },
  "server_type": 1
}, null

Deregister

Signature:

func Deregister() *C.char

Deregister cleans up the state for the client.

This function SHOULD be called when the application exits such that the configuration file is saved correctly. Note that saving of the configuration file also happens in other cases, such as after getting a VPN configuration. Thus it is often not problematic if this function cannot be called due to a client crash.

If no client is available or deregistering fails, it returns an error.

Example Input: Deregister()

Example Output:

{
  "message": {
    "en": "failed to deregister"
  },
  "misc": false
}

DiscoOrganizations

Signature:

func DiscoOrganizations(c C.uintptr_t, search *C.char) (*C.char, *C.char)

DiscoOrganizations gets the organizations from discovery, returned as types/discovery/discovery.go Organizations marshalled as JSON.

c is the Cookie that needs to be passed. Create a new Cookie using CookieNew
search is the search string for filtering the list.

If any of the words in the search query is not contained in any of the display names or keywords, the candidate is filtered. Otherwise they are ranked based on the levenshtein distance: Levenshtein Wikipedia. If search is empty it returns ALL organizations currently known in common

If it was unsuccessful, it returns an error. Note that when the lib was built in release mode the data is almost always non-nil, even when an error has occurred This means it has just returned the cached list, the error should then not be handled in a fatal way. E.g. show the returned cache list but log the error or show the error with a warning.

Example Input: DiscoOrganizations(myCookie, "")

Example Output:

{
 "organization_list": [
   {
     "display_name": {
       "en": "Academic Network of Albania - RASH"
     },
     "org_id": "https://idp.rash.al/simplesaml/saml2/idp/metadata.php",
   },
   {
     "display_name": {
       "da": "Dansk Sprognævn",
       "en": "Danish Language Council"
     },
     "org_id": "http://idp.dsn.dk/adfs/services/trust",
   },
   {
     "display_name": {
       "da": "Erhvervsakademi Aarhus",
       "en": "Business Academy Aarhus"
     },
     "org_id": "http://adfs.eaaa.dk/adfs/services/trust",
}, null

Example Input: DiscoOrganizations(myCookie, "rash")

Example Output:

	{
	 "organization_list": [
	   {
	     "display_name": {
	       "en": "Academic Network of Albania - RASH"
	     },
	     "org_id": "https://idp.rash.al/simplesaml/saml2/idp/metadata.php",
	   },
      ]
	}, null

DiscoServers

Signature:

func DiscoServers(c C.uintptr_t, search *C.char) (*C.char, *C.char)

DiscoServers gets the servers from discovery, returned as types/discovery/discovery.go Servers marshalled as JSON

c is the Cookie that needs to be passed. Create a new Cookie using CookieNew
search is the search string for filtering the list.

If any of the words in the search query is not contained in any of the display names or keywords, the candidate is filtered. Otherwise they are ranked based on the levenshtein distance: Levenshtein Wikipedia. If search is empty it returns ALL servers currently known in common

If it was unsuccessful, it returns an error. Note that when the lib was built in release mode the data is almost always non-nil, even when an error has occurred. This means it has just returned the cached list, the error should then not be handled in a fatal way. E.g. show the returned cache list but log the error or show the error with a warning.

Example Input: DiscoServers(myCookie, "")

Example Output:

	{
	 "server_list": [
	   {
	     "base_url": "https://eduvpn.rash.al/",
          "country_code": "AL",
	     "server_type": "secure_internet",
	   },
	   {
	     "base_url": "https://eduvpn.deic.dk/",
          "country_code": "DK",
	     "server_type": "secure_internet",
	} , null

Example Input: DiscoServers(myCookie, "heanet")

Example Output:

	{
	 "server_list": [
         {
           "base_url": "https://eduvpn.heanet.ie/",
           "display_name": {
             "en": "HEAnet Staff"
            },
           "server_type": "institute_access",
         },
       ]
	} , null

DiscoveryStartup

Signature:

func DiscoveryStartup(refresh C.RefreshList) *C.char

DiscoveryStartup does a discovery request in the background.

The refresh argument is a callback that is called when the refreshing is done.

When this callback is thus called, the app SHOULD refresh the server list of the already configured servers. This DiscoveryStartup function MUST be called after calling Register.

ExpiryTimes

Signature:

func ExpiryTimes() (*C.char, *C.char)

ExpiryTimes gets the expiry times for the current server

Expiry times are just fields that represent unix timestamps at which to do certain events regarding expiry, e.g. when to show the renew button, when to show expiry notifications

The expiry times structure is defined in types/server/server.go Expiry If some error occurs, it is returned as types/error/error.go Error

Example Input: ExpiryTimes()

Example Output (1...4 are unix timestamps):

{
     "start_time": 1,
     "end_time": 2,
     "button_time": 3,
     "countdown_time": 4,
     "notification_times": [
         1,
         2,
     ],
}, null

FreeString

Signature:

func FreeString(addr *C.char)

FreeString frees a string that was allocated by the eduvpn-common Go library.

This happens when we return strings, such as errors from the Go lib back to the client. The client MUST thus ensure that this memory is freed using this function. Simply pass the pointer to the string in here.

Example Input: FreeString(strPtr)

GetConfig

Signature:

func GetConfig(c C.uintptr_t, _type C.int, id *C.char, pTCP C.int, startup C.int) (*C.char, *C.char)

GetConfig gets a configuration for the server. It returns additional information in case WireGuard over Proxyguard is used (see the last example)

c is the cookie that is used for cancellation. Create a cookie first with CookieNew, this same cookie is also used for replying to state transitions

_type is the type of server that needs to be added. This type is defined in types/server/server.go Type

id is the identifier of the string

In case of secure internet: The organization ID
In case of custom server: The base URL
In case of institute access: The base URL

pTCP is if we prefer TCP or not to get the configuration, non-zero means yes

startup is if the client is just starting up, set this to true (non-zero) if you autoconnect to a server on startup. If this startup value is true (non-zero) then any authorization or other callacks (profile/location) are not triggered

After getting a configuration, the FSM moves to the GOT_CONFIG state The return data is the configuration, marshalled as JSON and defined in types/server/server.go Configuration

If the config cannot be retrieved it returns an error as types/error/error.go Error.

The current state callbacks MUST be handled:

ASK_PROFILE

This asks the client for profile.

This is called when the user/client has not set a profile for this server before, or the current profile is invalid

When the user has selected a profile, reply with the choice using the CookieReply function and the profile ID e.g. CookieReply(cookie, "wireguard"). CookieReply can be done in the background as the Go library waits for a reply

The data for this transition is defined in types/server/server.go RequiredAskTransition with embedded data Profiles in types/server/server.go. Note that RequiredAskTransition contains the cookie to be used for the CookieReply.

So a client would:

Parse the data to get the cookie and data
get the cookie
get the profiles from the data
show it in the UI and then reply with CookieReply using the choice

ASK_LOCATION

This asks the client for a location. Note that under normal circumstances, this callback is not actually called as the home organization for the secure internet server is set as the current if for some reason, an invalid location has been configured, the library will ask the client for a new one

When the user has selected a location, reply with the choice using the CookieReply function and the location ID e.g. CookieReply(cookie, "nl")

CookieReply can be done in the background as the Go library waits for a reply The data for this transition is defined in types/server/server.go RequiredAskTransition with embedded data a list of strings ([]string)

Note that RequiredAskTransition contains the cookie to be used for the CookieReply function,

So a client would:

Parse the data to get the cookie and data
get the cookie
get the list of locations from the data
show it in the UI and then reply with CookieReply using the choice

OAUTH_STARTED

OAUTH_STARTED: This indicates that the OAuth procedure has been started, it returns the URL as the data. The client should open the webbrowser with this URL and continue the authorization process. Note: For mobile platforms this returns a Cookie and data (json: {"cookie": x, "data": url}). This url should also be opened in the browser like desktop platforms. But these platforms also need to reply to the library to give back the full authorization code URI with CookieReply(x, uri). E.g. CookieReply(x, "/callback?code=...&state=...&iss=...") this is the path of the request that the apps get back when the user clicks approve. For this, apps need to register an app url or sorts. For the valid values for app URLs, see the redirect URIs for mobile platforms here https://git.sr.ht/~fkooman/vpn-user-portal/tree/v3/item/src/OAuth/VpnClientDb.php

The client should open the webbrowser with this URL and continue the authorization process. This is only called if authorization needs to be retriggered

Example Input (3=custom server): GetConfig(myCookie, 3, "https://demo.eduvpn.nl/", 0, 0)

Example Output (2=WireGuard):

{
 "config": "[Interface]\nPrivateKey = ...\nAddress = ...\nDNS = ...\n\n[Peer]\nPublicKey = ...=\nAllowedIPs = 0.0.0.0/0,::/0\nEndpoint = ...",
 "protocol": 2,
 "default_gateway": true,
 "should_failover": true, <- whether or not the failover procedure should happen
}

Example Output (3=WireGuard + Proxyguard):

{
"config":"[Interface]\nMTU = ...\nAddress = ...\nDNS = ...\nPrivateKey = ...\n[Peer]\nPublicKey = ...\nAllowedIPs = ...\nEndpoint = 127.0.0.1:x\n",
"protocol":3,
"default_gateway":true,
"should_failover":true,
"proxy":{"source_port":38683,"listen":"127.0.0.1:59812","peer":"https://..."}
}

InState

Signature:

func InState(fsmState C.int) (C.int, *C.char)

InState checks if the FSM is in fsmState.

Example Input: InState(5)

Example Output: 1, null

Register

Signature:

func Register(
   name *C.char,
   version *C.char,
   configDirectory *C.char,
   cb C.StateCB,
   debug C.int,
) *C.char

Name is the name of the client, must be a valid client ID.

Version is the version of the client. This version field is used for the user agent in all HTTP requests.

cb is the state callback. It takes three arguments: The old state, the new state and the data for the state as JSON.

Note that the states are defined in client/fsm.go, e.g. Main (in Go: StateMain), ASK_PROFILE (in Go: StateAskProfile)
This callback returns non-zero if the state transition is handled. This is used to check if the client handles the needed transitions

debug, if non-zero, enables debugging mode for the library, this means:

Log everything in debug mode, so you can get more detail of what is going on
Write the state graph to a file in the configDirectory. This can be used to create a FSM png file with mermaid https://mermaid.js.org/

After registering, the FSM is initialized and the state transition MAIN should have been completed If some error occurs during registering, it is returned as a types/error/error.go Error

Example Input: Register("org.eduvpn.app.linux", "0.0.1", "/tmp/eduvpn-common", myCallbackFunc, 1)

Example Output:

{
  "message": {
    "en": "failed to register, a VPN state is already present"
  },
  "misc": false
}

RemoveServer

Signature:

func RemoveServer(_type C.int, id *C.char) *C.char

RemoveServer removes a server from the eduvpn-common server list

_type is the type of server that needs to be added. This type is defined in types/server/server.go Type

id is the identifier of the string:

In case of secure internet: The organization ID
In case of custom server: The base URL
In case of institute access: The base URL

If the server cannot be removed it returns the error types/error/error.go Error.

Example Input (3=custom server): RemoveServer(3, "bogus")

Example Output:

{
  "message": {
    "en": "failed to remove server"
  },
  "misc": false
}

RenewSession

Signature:

func RenewSession(c C.uintptr_t) *C.char

RenewSession renews the session of the VPN

This essentially means that the OAuth tokens are deleted. And it also possibly re-runs every state callback you need when getting a config. So least you MUST handle the OAuth started transition

It returns an error if unsuccessful. Example Input: RenewSession(myCookie)

Example Output:

{
  "message": {
    "en": "could not renew session"
  },
  "misc": false
}

ServerList

Signature:

func ServerList() (*C.char, *C.char)

ServerList gets the list of servers that are currently added

This is NOT the discovery list, but the servers that have previously been added with AddServer.

It returns the server list as a JSON string defined in types/server/server.go List. If the server list cannot be retrieved it returns a nil string and an error.

Example Input: ServerList()

Example Output (current profile here is empty as none has been chosen yet):

{
  "institute_access_servers": [
    {
      "display_name": {
        "en": "Demo"
      },
      "identifier": "https://demo.eduvpn.nl/",
      "profiles": {
        "current": ""
      },
      "support_contacts": [
        "mailto:eduvpn@surf.nl"
      ],
      "delisted": false
    }
  ]
}, null

SetProfileID

Signature:

func SetProfileID(data *C.char) *C.char

SetProfileID sets the profile ID of the current serrver.

This MUST only be called if the user/client wishes to manually set a profile instead of the common lib asking for one using a transition.

data is the profile ID.

It returns an error if unsuccessful. Example Input: SetProfileID("splittunnel")

Example Output:

{
  "message": {
    "en": "profile does not exist"
  },
  "misc": false
}

SetSecureLocation

Signature:

func SetSecureLocation(orgID *C.char, cc *C.char) *C.char

SetSecureLocation sets the location for the secure internet server if it exists.

This MUST only be called if the user/client wishes to manually set a location instead of the common lib asking for one using a transition.

orgID is the organisation ID for the secure internet server
cc is the location ID/country code

It returns an error if unsuccessful. Example Input: SetSecureLocation("http://idp.geant.org/", "nl")

Example Output:

{
  "message": {
    "en": "location does not exist"
  },
  "misc": false
}

SetState

Signature:

func SetState(fsmState C.int) *C.char

SetState sets the state of the state machine.

Note: this transitions the FSM into the new state without passing any data to it. Example Input: SetState(5)

Example Output: null

SetTokenHandler

Signature:

func SetTokenHandler(getter C.TokenGetter, setter C.TokenSetter) *C.char

SetTokenHandler sets the token getters and token setters for OAuth.

Because the data that is saved does not contain OAuth tokens for server, the common lib asks and sets the tokens using these callback functions. The client can thus pass callbacks to this function so that the tokens can be securely stored in a keyring.

The client must pass two callback arguments to this function:

getter is the void function that gets tokens from the client. It takes three arguments:

The server for which to get the tokens for, marshalled as JSON and defined in types/server/server.go Current
The output buffer
The length of the output buffer. This 'output buffer' must contain the tokens, marshalled as JSON that is defined in types/server/server.go Tokens

setter is the void function that sets tokens. It takes two arguments:

The server for which to get the tokens for, marshalled as JSON and defined in types/server/server.go Current
The tokens, defined in types/server/server.go Tokens marshalled as JSON

It returns an error when the tokens cannot be set. Example Input: SetTokenHandler(getterFunc, setterFunc)

Example Output: null

StartFailover

Signature:

func StartFailover(c C.uintptr_t, gateway *C.char, mtu C.int, readRxBytes C.ReadRxBytes) (C.int, *C.char)

StartFailover starts the 'failover' procedure in eduvpn-common.

Failover has one primary goal: check if the VPN can reach the gateway. This can be used to check whether or not the client needs to 'failover' to prefer TCP (if currently using UDP). Which is useful to go from a broken WireGuard connection to OpenVPN over TCP.

c is the cookie that is passed for cancellation. To create a cookie, use the CookieNew function
gateway is the gateway IP of the VPN. You MAY calculate this with the CalculateGateway function
readRxBytes is a function that returns the current rx bytes of the VPN interface, this should return a long long int in c

It returns a boolean whether or not the common lib has determined that it cannot reach the gateway. Non-zero=dropped, zero=not dropped. It also returns an error, if it fails to indicate if it has dropped or not. In this case, dropped is also set to zero.

Example Input: StartFailover(myCookie, "10.10.10.1", 1400, myRxBytesReader)

Example Output: 1, null

StartProxyguard

Signature:

func StartProxyguard(c C.uintptr_t, listen *C.char, tcpsp C.int, peer *C.char, proxySetup C.ProxySetup, proxyReady C.ProxyReady) *C.char

StartProxyguard starts the 'proxyguard' procedure in eduvpn-common. eduvpn-common currently also cleans up the running ProxyGuard process in cleanup. If the proxy cannot be started it returns an error.

This function proxies WireGuard UDP connections over HTTP: ProxyGuard on Codeberg.

These input variables can be gotten from the configuration that is retrieved using the proxy JSON key

c is the cookie. Note that if you cancel/delete the cookie, ProxyGuard gets cleaned up. Common automatically cleans up ProxyGuard when Cleanup is called, but it is good to cleanup yourself too.
listen is the ip:port of the local udp connection, this is what is set to the WireGuard endpoint
tcpsp is the TCP source port. Pass 0 if you do not route based on source port, so far only the Linux client has to pass non-zero.
peer is the ip:port of the remote server
proxySetup is a callback which is called when the socket is setting up, this can be used for configuring routing in the client. It takes two arguments: the file descriptor (integer) and a JSON list of IPs the client connects to
proxyReady is a callback when the proxy is ready to be used. This is only called when the client is not connected yet. Use this to determine when the actual wireguard connection can be started. This callback returns and takes no arguments

Example Input: StartProxyGuard(myCookie, "127.0.0.1:1337", 0, "5.5.5.5:51820", proxySetupCB, proxyReadyCB)

Example Output: null

eduVPN-common documentation

Table of contents

About the API

Functions

AddServer

CalculateGateway

Cleanup

CookieCancel

CookieDelete

CookieNew

CookieReply

CurrentServer

Deregister

DiscoOrganizations

DiscoServers

DiscoveryStartup

ExpiryTimes

FreeString

GetConfig

ASK_PROFILE

ASK_LOCATION

OAUTH_STARTED

InState

Register

RemoveServer

RenewSession

ServerList

SetProfileID

SetSecureLocation

SetState

SetTokenHandler

StartFailover

StartProxyguard