README
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Testing against a local DHCP server
These instructions will run a DHCP server locally on your computer for testing the DHCP client.
Run qemu with Fuchsia. We'll give Fuchsia two NICs so that we can test the interaction between them and DHCP. Make all the tunnels:
sudo tunctl -u $USER -t qemu
sudo tunctl -u $USER -t qemu-extra
sudo ifconfig qemu up
sudo ifconfig qemu-extra up
Now build and run Fuchsia with those two ports:
fx build && fx qemu -kN -- -nic tap,ifname=qemu-extra,model=e1000
Now install a DHCP server.
sudo apt-get install isc-dhcp-server
ps aux | grep dhcp
If dhcpd was started as part of that, kill it:
sudo systemctl disable isc-dhcp-server.service
Make a file called /tmp/dhcpd.conf with these contents:
default-lease-time 3600;
max-lease-time 7200;
authoritative;
subnet 172.18.0.0 netmask 255.255.0.0 {
option routers 172.18.0.1;
option subnet-mask 255.255.0.0;
option domain-search "testdomain18.lan";
option domain-name-servers 172.18.0.1;
range 172.18.0.10 172.18.0.100;
}
subnet 172.19.0.0 netmask 255.255.0.0 {
option routers 172.19.0.1;
option subnet-mask 255.255.0.0;
option domain-search "testdomain19.lan";
option domain-name-servers 172.19.0.1;
range 172.19.0.10 172.19.0.100;
}
dhcpd knows which addresses to serve on which nics based on matching the existing IP address on the NIC so you need to set those:
sudo ifconfig qemu 172.18.0.1
sudo ifconfig qemu-extra 172.19.0.1
Now we'll run dhcpd. You can use the filenames below or modify them.
If the leases file doesn't already exist, dhcpd might complain. Go ahead and create the file first:
sudo touch /tmp/dhcpd.leases
Now run:
sudo dhcpd -4 -f -d -cf /tmp/dhcpd.conf -lf /tmp/dhcpd.leases qemu qemu-extra
Now Fuchsia should get DHCP addresses and you'll see debug output for each step in the dhcpd output.
Documentation
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Overview ¶
Package dhcp implements a DHCP client and server as described in RFC 2131.
Index ¶
Constants ¶
const ( // ServerPort is the well-known UDP port number for a DHCP server. ServerPort = 67 // ClientPort is the well-known UDP port number for a DHCP client. ClientPort = 68 )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type AcquiredFunc ¶
type AcquiredFunc func(oldAddr, newAddr tcpip.AddressWithPrefix, cfg Config)
type Client ¶
type Client struct {
// contains filtered or unexported fields
}
Client is a DHCP client.
func NewClient ¶
func NewClient( s *stack.Stack, nicid tcpip.NICID, linkAddr tcpip.LinkAddress, acquisition, backoff, retransmission time.Duration, acquiredFunc AcquiredFunc, ) *Client
NewClient creates a DHCP client.
acquiredFunc will be called after each DHCP acquisition, and is responsible for making necessary modifications to the stack state.
type Config ¶
type Config struct {
ServerAddress tcpip.Address // address of the server
SubnetMask tcpip.AddressMask // client address subnet mask
Router []tcpip.Address // client router addresses
DNS []tcpip.Address // client DNS server addresses
LeaseLength Seconds // length of the address lease
RenewTime Seconds // time until client enters RENEWING state
RebindTime Seconds // time until client enters REBINDING state
Declined bool // server sent a NAK
}
Config is standard DHCP configuration.
type Info ¶
type Info struct {
// NICID is the identifer to the associated NIC.
NICID tcpip.NICID
// LinkAddr is the link-address of the associated NIC.
LinkAddr tcpip.LinkAddress
// Acquisition is the duration within which a complete DHCP transaction must
// complete before timing out.
Acquisition time.Duration
// Backoff is the duration for which the client must wait before starting a
// new DHCP transaction after a failed transaction.
Backoff time.Duration
// Retransmission is the duration to wait before resending a DISCOVER or
// REQUEST within an active transaction.
Retransmission time.Duration
// Addr is the acquired network address.
Addr tcpip.AddressWithPrefix
// Server is the network address of the DHCP server.
Server tcpip.Address
// State is the DHCP client state.
State dhcpClientState
// OldAddr is the address reported in the last call to acquiredFunc.
OldAddr tcpip.AddressWithPrefix
}
type Seconds ¶
type Seconds uint32
Seconds represents a time duration in seconds.
RFC 2131 Section 3.3 https://tools.ietf.org/html/rfc2131#section-3.3
Throughout the protocol, times are to be represented in units of seconds. Representing relative times in units of seconds in an unsigned 32 bit word gives a range of relative times from 0 to approximately 100 years, which is sufficient for the relative times to be measured using DHCP.
type Server ¶
type Server struct {
// contains filtered or unexported fields
}
Server is a DHCP server.
type Stats ¶
type Stats struct {
InitAcquire tcpip.StatCounter
RenewAcquire tcpip.StatCounter
RebindAcquire tcpip.StatCounter
SendDiscovers tcpip.StatCounter
RecvOffers tcpip.StatCounter
SendRequests tcpip.StatCounter
RecvAcks tcpip.StatCounter
RecvNaks tcpip.StatCounter
SendDiscoverErrors tcpip.StatCounter
SendRequestErrors tcpip.StatCounter
RecvOfferErrors tcpip.StatCounter
RecvOfferUnexpectedType tcpip.StatCounter
RecvOfferOptsDecodeErrors tcpip.StatCounter
RecvOfferTimeout tcpip.StatCounter
RecvOfferAcquisitionTimeout tcpip.StatCounter
RecvAckErrors tcpip.StatCounter
RecvNakErrors tcpip.StatCounter
RecvAckOptsDecodeErrors tcpip.StatCounter
RecvAckAddrErrors tcpip.StatCounter
RecvAckUnexpectedType tcpip.StatCounter
RecvAckTimeout tcpip.StatCounter
RecvAckAcquisitionTimeout tcpip.StatCounter
ReacquireAfterNAK tcpip.StatCounter
}
Stats collects DHCP statistics per client.
Source Files