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Pull request 2245: 4923 gopacket DHCP vol.8

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Updates #4923.

Squashed commit of the following:

commit 0bfccf8bc1e63c4f5a01ce7f268e767969b368a0
Merge: 305f9fe2f 0e5e8e4dd
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Jul 3 15:12:43 2024 +0300

    Merge branch 'master' into 4923-gopacket-dhcp-vol.8

commit 305f9fe2fec033f28385dfe2bbee6a27a83b9702
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Jul 2 17:03:01 2024 +0300

    dhcpsvc: adjust interface

commit f05b9f42e2f50325ddaf09b5fed84b62e48c5120
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Jul 2 16:59:39 2024 +0300

    dhcpsvc: use logger

commit 4779f945baf9c8722d07d589928a86290a37d3ab
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Jul 2 14:59:22 2024 +0300

    dhcpsvc: add todo

commit ae1713e5f717a66863eb0289e3aa66c7069ac8bf
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Jul 1 15:49:22 2024 +0300

    dhcpsvc: use slog
This commit is contained in:
Eugene Burkov
2024-07-03 15:29:54 +03:00
parent 0e5e8e4dde
commit beeb8f0522
9 changed files with 368 additions and 212 deletions
Download Patch File Download Diff File Expand all files Collapse all files

253
internal/dhcpsvc/v4.go
View File

@@ -1,13 +1,15 @@
package dhcpsvc
import (
"context"
"fmt"
"log/slog"
"net"
"net/netip"
"slices"
"time"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/netutil"
"github.com/google/gopacket/layers"
)
@@ -43,25 +45,133 @@ type IPv4Config struct {
}
// validate returns an error in conf if any.
func (conf *IPv4Config) validate() (err error) {
switch {
case conf == nil:
func (c *IPv4Config) validate() (err error) {
if c == nil {
return errNilConfig
case !conf.Enabled:
return nil
case !conf.GatewayIP.Is4():
return newMustErr("gateway ip", "be a valid ipv4", conf.GatewayIP)
case !conf.SubnetMask.Is4():
return newMustErr("subnet mask", "be a valid ipv4 cidr mask", conf.SubnetMask)
case !conf.RangeStart.Is4():
return newMustErr("range start", "be a valid ipv4", conf.RangeStart)
case !conf.RangeEnd.Is4():
return newMustErr("range end", "be a valid ipv4", conf.RangeEnd)
case conf.LeaseDuration <= 0:
return newMustErr("lease duration", "be less than %d", conf.LeaseDuration)
default:
} else if !c.Enabled {
return nil
}
var errs []error
if !c.GatewayIP.Is4() {
err = newMustErr("gateway ip", "be a valid ipv4", c.GatewayIP)
errs = append(errs, err)
}
if !c.SubnetMask.Is4() {
err = newMustErr("subnet mask", "be a valid ipv4 cidr mask", c.SubnetMask)
errs = append(errs, err)
}
if !c.RangeStart.Is4() {
err = newMustErr("range start", "be a valid ipv4", c.RangeStart)
errs = append(errs, err)
}
if !c.RangeEnd.Is4() {
err = newMustErr("range end", "be a valid ipv4", c.RangeEnd)
errs = append(errs, err)
}
if c.LeaseDuration <= 0 {
err = newMustErr("icmp timeout", "be positive", c.LeaseDuration)
errs = append(errs, err)
}
return errors.Join(errs...)
}
// netInterfaceV4 is a DHCP interface for IPv4 address family.
type netInterfaceV4 struct {
// gateway is the IP address of the network gateway.
gateway netip.Addr
// subnet is the network subnet.
subnet netip.Prefix
// addrSpace is the IPv4 address space allocated for leasing.
addrSpace ipRange
// implicitOpts are the options listed in Appendix A of RFC 2131 and
// initialized with default values. It must not have intersections with
// explicitOpts.
implicitOpts layers.DHCPOptions
// explicitOpts are the user-configured options. It must not have
// intersections with implicitOpts.
explicitOpts layers.DHCPOptions
// netInterface is embedded here to provide some common network interface
// logic.
netInterface
}
// newNetInterfaceV4 creates a new DHCP interface for IPv4 address family with
// the given configuration. It returns an error if the given configuration
// can't be used.
func newNetInterfaceV4(
ctx context.Context,
l *slog.Logger,
name string,
conf *IPv4Config,
) (i *netInterfaceV4, err error) {
l = l.With(
keyInterface, name,
keyFamily, netutil.AddrFamilyIPv4,
)
if !conf.Enabled {
l.DebugContext(ctx, "disabled")
return nil, nil
}
maskLen, _ := net.IPMask(conf.SubnetMask.AsSlice()).Size()
subnet := netip.PrefixFrom(conf.GatewayIP, maskLen)
switch {
case !subnet.Contains(conf.RangeStart):
return nil, fmt.Errorf("range start %s is not within %s", conf.RangeStart, subnet)
case !subnet.Contains(conf.RangeEnd):
return nil, fmt.Errorf("range end %s is not within %s", conf.RangeEnd, subnet)
}
addrSpace, err := newIPRange(conf.RangeStart, conf.RangeEnd)
if err != nil {
return nil, err
} else if addrSpace.contains(conf.GatewayIP) {
return nil, fmt.Errorf("gateway ip %s in the ip range %s", conf.GatewayIP, addrSpace)
}
i = &netInterfaceV4{
gateway: conf.GatewayIP,
subnet: subnet,
addrSpace: addrSpace,
netInterface: netInterface{
name: name,
leaseTTL: conf.LeaseDuration,
logger: l,
},
}
i.implicitOpts, i.explicitOpts = conf.options(ctx, l)
return i, nil
}
// netInterfacesV4 is a slice of network interfaces of IPv4 address family.
type netInterfacesV4 []*netInterfaceV4
// find returns the first network interface within ifaces containing ip. It
// returns false if there is no such interface.
func (ifaces netInterfacesV4) find(ip netip.Addr) (iface4 *netInterface, ok bool) {
i := slices.IndexFunc(ifaces, func(iface *netInterfaceV4) (contains bool) {
return iface.subnet.Contains(ip)
})
if i < 0 {
return nil, false
}
return &ifaces[i].netInterface, true
}
// options returns the implicit and explicit options for the interface. The two
@@ -69,14 +179,14 @@ func (conf *IPv4Config) validate() (err error) {
// values.
//
// TODO(e.burkov): DRY with the IPv6 version.
func (conf *IPv4Config) options() (implicit, explicit layers.DHCPOptions) {
func (c *IPv4Config) options(ctx context.Context, l *slog.Logger) (imp, exp layers.DHCPOptions) {
// Set default values of host configuration parameters listed in Appendix A
// of RFC-2131.
implicit = layers.DHCPOptions{
imp = layers.DHCPOptions{
// Values From Configuration
layers.NewDHCPOption(layers.DHCPOptSubnetMask, conf.SubnetMask.AsSlice()),
layers.NewDHCPOption(layers.DHCPOptRouter, conf.GatewayIP.AsSlice()),
layers.NewDHCPOption(layers.DHCPOptSubnetMask, c.SubnetMask.AsSlice()),
layers.NewDHCPOption(layers.DHCPOptRouter, c.GatewayIP.AsSlice()),
// IP-Layer Per Host
@@ -228,110 +338,29 @@ func (conf *IPv4Config) options() (implicit, explicit layers.DHCPOptions) {
// See https://datatracker.ietf.org/doc/html/rfc1122#section-4.2.3.6.
layers.NewDHCPOption(layers.DHCPOptTCPKeepAliveGarbage, []byte{0x1}),
}
slices.SortFunc(implicit, compareV4OptionCodes)
slices.SortFunc(imp, compareV4OptionCodes)
// Set values for explicitly configured options.
for _, exp := range conf.Options {
i, found := slices.BinarySearchFunc(implicit, exp, compareV4OptionCodes)
for _, o := range c.Options {
i, found := slices.BinarySearchFunc(imp, o, compareV4OptionCodes)
if found {
implicit = slices.Delete(implicit, i, i+1)
imp = slices.Delete(imp, i, i+1)
}
i, found = slices.BinarySearchFunc(explicit, exp, compareV4OptionCodes)
if exp.Length > 0 {
explicit = slices.Insert(explicit, i, exp)
i, found = slices.BinarySearchFunc(exp, o, compareV4OptionCodes)
if o.Length > 0 {
exp = slices.Insert(exp, i, o)
} else if found {
explicit = slices.Delete(explicit, i, i+1)
exp = slices.Delete(exp, i, i+1)
}
}
log.Debug("dhcpsvc: v4: implicit options: %s", implicit)
log.Debug("dhcpsvc: v4: explicit options: %s", explicit)
l.DebugContext(ctx, "options", "implicit", imp, "explicit", exp)
return implicit, explicit
return imp, exp
}
// compareV4OptionCodes compares option codes of a and b.
func compareV4OptionCodes(a, b layers.DHCPOption) (res int) {
return int(a.Type) - int(b.Type)
}
// netInterfaceV4 is a DHCP interface for IPv4 address family.
type netInterfaceV4 struct {
// gateway is the IP address of the network gateway.
gateway netip.Addr
// subnet is the network subnet.
subnet netip.Prefix
// addrSpace is the IPv4 address space allocated for leasing.
addrSpace ipRange
// implicitOpts are the options listed in Appendix A of RFC 2131 and
// initialized with default values. It must not have intersections with
// explicitOpts.
implicitOpts layers.DHCPOptions
// explicitOpts are the user-configured options. It must not have
// intersections with implicitOpts.
explicitOpts layers.DHCPOptions
// netInterface is embedded here to provide some common network interface
// logic.
netInterface
}
// newNetInterfaceV4 creates a new DHCP interface for IPv4 address family with
// the given configuration. It returns an error if the given configuration
// can't be used.
func newNetInterfaceV4(name string, conf *IPv4Config) (i *netInterfaceV4, err error) {
if !conf.Enabled {
return nil, nil
}
maskLen, _ := net.IPMask(conf.SubnetMask.AsSlice()).Size()
subnet := netip.PrefixFrom(conf.GatewayIP, maskLen)
switch {
case !subnet.Contains(conf.RangeStart):
return nil, fmt.Errorf("range start %s is not within %s", conf.RangeStart, subnet)
case !subnet.Contains(conf.RangeEnd):
return nil, fmt.Errorf("range end %s is not within %s", conf.RangeEnd, subnet)
}
addrSpace, err := newIPRange(conf.RangeStart, conf.RangeEnd)
if err != nil {
return nil, err
} else if addrSpace.contains(conf.GatewayIP) {
return nil, fmt.Errorf("gateway ip %s in the ip range %s", conf.GatewayIP, addrSpace)
}
i = &netInterfaceV4{
gateway: conf.GatewayIP,
subnet: subnet,
addrSpace: addrSpace,
netInterface: netInterface{
name: name,
leaseTTL: conf.LeaseDuration,
},
}
i.implicitOpts, i.explicitOpts = conf.options()
return i, nil
}
// netInterfacesV4 is a slice of network interfaces of IPv4 address family.
type netInterfacesV4 []*netInterfaceV4
// find returns the first network interface within ifaces containing ip. It
// returns false if there is no such interface.
func (ifaces netInterfacesV4) find(ip netip.Addr) (iface4 *netInterface, ok bool) {
i := slices.IndexFunc(ifaces, func(iface *netInterfaceV4) (contains bool) {
return iface.subnet.Contains(ip)
})
if i < 0 {
return nil, false
}
return &ifaces[i].netInterface, true
}