github.com/zaolin/u-root@v0.0.0-20200428085104-64aaafd46c6d/pkg/dhclient/dhcp6.go (about)

     1  // Copyright 2017-2018 the u-root Authors. All rights reserved
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package dhclient
     6  
     7  import (
     8  	"fmt"
     9  	"net"
    10  	"net/url"
    11  	"os"
    12  
    13  	"github.com/insomniacslk/dhcp/dhcpv4"
    14  	"github.com/insomniacslk/dhcp/dhcpv6"
    15  	"github.com/vishvananda/netlink"
    16  	"golang.org/x/sys/unix"
    17  )
    18  
    19  // Packet6 implements Packet for IPv6 DHCP.
    20  type Packet6 struct {
    21  	p     *dhcpv6.Message
    22  	iface netlink.Link
    23  }
    24  
    25  // NewPacket6 wraps a DHCPv6 packet with some convenience methods.
    26  func NewPacket6(iface netlink.Link, p *dhcpv6.Message) *Packet6 {
    27  	return &Packet6{
    28  		p:     p,
    29  		iface: iface,
    30  	}
    31  }
    32  
    33  // Message returns the unwrapped DHCPv6 packet.
    34  func (p *Packet6) Message() (*dhcpv4.DHCPv4, *dhcpv6.Message) {
    35  	return nil, p.p
    36  }
    37  
    38  // Link returns the interface this packet was received for.
    39  func (p *Packet6) Link() netlink.Link {
    40  	return p.iface
    41  }
    42  
    43  // Configure6 adds IPv6 addresses, routes, and DNS servers to the system.
    44  func Configure6(iface netlink.Link, packet *dhcpv6.Message) error {
    45  	p := NewPacket6(iface, packet)
    46  	return p.Configure()
    47  }
    48  
    49  // Configure configures interface using this packet.
    50  func (p *Packet6) Configure() error {
    51  	l := p.Lease()
    52  	if l == nil {
    53  		return fmt.Errorf("no lease returned")
    54  	}
    55  
    56  	// Add the address to the iface.
    57  	dst := &netlink.Addr{
    58  		IPNet: &net.IPNet{
    59  			IP:   l.IPv6Addr,
    60  			Mask: net.IPMask(net.ParseIP("ffff:ffff:ffff:ffff::")),
    61  		},
    62  		PreferedLft: int(l.PreferredLifetime),
    63  		ValidLft:    int(l.ValidLifetime),
    64  		// Optimistic DAD (Duplicate Address Detection) means we can
    65  		// use the address before DAD is complete. The DHCP server's
    66  		// job was to give us a unique IP so there is little risk of a
    67  		// collision.
    68  		Flags: unix.IFA_F_OPTIMISTIC,
    69  	}
    70  	if err := netlink.AddrReplace(p.iface, dst); err != nil {
    71  		if os.IsExist(err) {
    72  			return fmt.Errorf("add/replace %s to %v: %v", dst, p.iface, err)
    73  		}
    74  	}
    75  
    76  	if ips := p.DNS(); ips != nil {
    77  		if err := WriteDNSSettings(ips, nil, ""); err != nil {
    78  			return err
    79  		}
    80  	}
    81  	return nil
    82  }
    83  
    84  func (p *Packet6) String() string {
    85  	return fmt.Sprintf("IPv6 DHCP Lease IP %s", p.Lease().IPv6Addr)
    86  }
    87  
    88  // Lease returns lease information assigned.
    89  func (p *Packet6) Lease() *dhcpv6.OptIAAddress {
    90  	iana := p.p.Options.OneIANA()
    91  	if iana == nil {
    92  		return nil
    93  	}
    94  
    95  	iaAddrOpt := iana.Options.GetOne(dhcpv6.OptionIAAddr)
    96  	iaAddr, ok := iaAddrOpt.(*dhcpv6.OptIAAddress)
    97  	if !ok {
    98  		return nil
    99  	}
   100  	return iaAddr
   101  }
   102  
   103  // DNS returns DNS servers assigned.
   104  func (p *Packet6) DNS() []net.IP {
   105  	return p.p.Options.DNS()
   106  }
   107  
   108  // Boot returns the boot file URL and parameters assigned.
   109  func (p *Packet6) Boot() (*url.URL, error) {
   110  	uri := p.p.Options.BootFileURL()
   111  	if len(uri) == 0 {
   112  		return nil, fmt.Errorf("packet does not contain boot file URL")
   113  	}
   114  	return url.Parse(uri)
   115  }
   116  
   117  // ISCSIBoot returns the target address and volume name to boot from if
   118  // they were part of the DHCP message.
   119  //
   120  // Parses the DHCPv6 Boot File for iSCSI target and volume as specified by RFC
   121  // 4173 and RFC 5970.
   122  func (p *Packet6) ISCSIBoot() (*net.TCPAddr, string, error) {
   123  	uri := p.p.Options.BootFileURL()
   124  	if len(uri) == 0 {
   125  		return nil, "", fmt.Errorf("packet does not contain boot file URL")
   126  	}
   127  	return parseISCSIURI(uri)
   128  }