Songmin Li d61e7e5e1f fix(dhcp): can not renew an ip address
The dhcp server is systemd-networkd, and the dhcp
plugin can request an ip but can not renew it.
The systemd-networkd just ignore the renew request.

```
2024/09/14 21:46:00 no DHCP packet received within 10s
2024/09/14 21:46:00 retrying in 31.529038 seconds
2024/09/14 21:46:42 no DHCP packet received within 10s
2024/09/14 21:46:42 retrying in 63.150490 seconds
2024/09/14 21:47:45 98184616c91f15419f5cacd012697f85afaa2daeb5d3233e28b0ec21589fb45a/iot/eth1: no more tries
2024/09/14 21:47:45 98184616c91f15419f5cacd012697f85afaa2daeb5d3233e28b0ec21589fb45a/iot/eth1: renewal time expired, rebinding
2024/09/14 21:47:45 Link "eth1" down. Attempting to set up
2024/09/14 21:47:45 98184616c91f15419f5cacd012697f85afaa2daeb5d3233e28b0ec21589fb45a/iot/eth1: lease rebound, expiration is 2024-09-14 22:47:45.309270751 +0800 CST m=+11730.048516519
```

Follow the https://datatracker.ietf.org/doc/html/rfc2131#section-4.3.6,
following options must not be sent in renew

- Requested IP Address
- Server Identifier

Since the upstream code has been inactive for 6 years,
we should switch to another dhcpv4 library.
The new selected one is https://github.com/insomniacslk/dhcp.

Signed-off-by: Songmin Li <lisongmin@protonmail.com>
2024-10-14 17:42:30 +02:00

63 lines
1.6 KiB
Go

package dhcpv4
import (
"net"
"github.com/u-root/uio/uio"
)
// IP implements DHCPv4 IP option marshaling and unmarshaling as described by
// RFC 2132, Sections 5.3, 9.1, 9.7, and others.
type IP net.IP
// FromBytes parses an IP from data in binary form.
func (i *IP) FromBytes(data []byte) error {
buf := uio.NewBigEndianBuffer(data)
*i = IP(buf.CopyN(net.IPv4len))
return buf.FinError()
}
// ToBytes returns a serialized stream of bytes for this option.
func (i IP) ToBytes() []byte {
return []byte(net.IP(i).To4())
}
// String returns a human-readable IP.
func (i IP) String() string {
return net.IP(i).String()
}
// GetIP returns code out of o parsed as an IP.
func GetIP(code OptionCode, o Options) net.IP {
v := o.Get(code)
if v == nil {
return nil
}
var ip IP
if err := ip.FromBytes(v); err != nil {
return nil
}
return net.IP(ip)
}
// OptBroadcastAddress returns a new DHCPv4 Broadcast Address option.
//
// The broadcast address option is described in RFC 2132, Section 5.3.
func OptBroadcastAddress(ip net.IP) Option {
return Option{Code: OptionBroadcastAddress, Value: IP(ip)}
}
// OptRequestedIPAddress returns a new DHCPv4 Requested IP Address option.
//
// The requested IP address option is described by RFC 2132, Section 9.1.
func OptRequestedIPAddress(ip net.IP) Option {
return Option{Code: OptionRequestedIPAddress, Value: IP(ip)}
}
// OptServerIdentifier returns a new DHCPv4 Server Identifier option.
//
// The server identifier option is described by RFC 2132, Section 9.7.
func OptServerIdentifier(ip net.IP) Option {
return Option{Code: OptionServerIdentifier, Value: IP(ip)}
}