vendor: add github.com/d2g

Godeps/Godeps.json

@@ -81,6 +81,14 @@
 			"Comment": "v2-53-g2688e91",
 			"Rev": "2688e91251d9d8e404e86dd8f096e23b2f086958"
 		},
+		{
+			"ImportPath": "github.com/d2g/dhcp4",
+			"Rev": "f0e4d29ff0231dce36e250b2ed9ff08412584bca"
+		},
+		{
+			"ImportPath": "github.com/d2g/dhcp4client",
+			"Rev": "bed07e1bc5b85f69c6f0fd73393aa35ec68ed892"
+		},
 		{
 			"ImportPath": "github.com/onsi/ginkgo",
 			"Comment": "v1.2.0-29-g7f8ab55",

vendor/github.com/d2g/dhcp4/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2013 Skagerrak Software Limited. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Skagerrak Software Limited nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/d2g/dhcp4/README.md

@@ -0,0 +1,5 @@
+# DHCP4 - A DHCP library written in Go.
+
+Warning: This library is still being developed.  Function calls will change.
+
+I've removed Server Functionality, for me this project supports the underlying DHCP format not the implementation.

vendor/github.com/d2g/dhcp4/constants.go

@@ -0,0 +1,121 @@
+package dhcp4
+
+// OpCodes
+const (
+	BootRequest OpCode = 1 // From Client
+	BootReply   OpCode = 2 // From Server
+)
+
+// DHCP Message Type 53
+const (
+	Discover MessageType = 1 // Broadcast Packet From Client - Can I have an IP?
+	Offer    MessageType = 2 // Broadcast From Server - Here's an IP
+	Request  MessageType = 3 // Broadcast From Client - I'll take that IP (Also start for renewals)
+	Decline  MessageType = 4 // Broadcast From Client - Sorry I can't use that IP
+	ACK      MessageType = 5 // From Server, Yes you can have that IP
+	NAK      MessageType = 6 // From Server, No you cannot have that IP
+	Release  MessageType = 7 // From Client, I don't need that IP anymore
+	Inform   MessageType = 8 // From Client, I have this IP and there's nothing you can do about it
+)
+
+// DHCP Options
+const (
+	End                          OptionCode = 255
+	Pad                          OptionCode = 0
+	OptionSubnetMask             OptionCode = 1
+	OptionTimeOffset             OptionCode = 2
+	OptionRouter                 OptionCode = 3
+	OptionTimeServer             OptionCode = 4
+	OptionNameServer             OptionCode = 5
+	OptionDomainNameServer       OptionCode = 6
+	OptionLogServer              OptionCode = 7
+	OptionCookieServer           OptionCode = 8
+	OptionLPRServer              OptionCode = 9
+	OptionImpressServer          OptionCode = 10
+	OptionResourceLocationServer OptionCode = 11
+	OptionHostName               OptionCode = 12
+	OptionBootFileSize           OptionCode = 13
+	OptionMeritDumpFile          OptionCode = 14
+	OptionDomainName             OptionCode = 15
+	OptionSwapServer             OptionCode = 16
+	OptionRootPath               OptionCode = 17
+	OptionExtensionsPath         OptionCode = 18
+
+	// IP Layer Parameters per Host
+	OptionIPForwardingEnableDisable          OptionCode = 19
+	OptionNonLocalSourceRoutingEnableDisable OptionCode = 20
+	OptionPolicyFilter                       OptionCode = 21
+	OptionMaximumDatagramReassemblySize      OptionCode = 22
+	OptionDefaultIPTimeToLive                OptionCode = 23
+	OptionPathMTUAgingTimeout                OptionCode = 24
+	OptionPathMTUPlateauTable                OptionCode = 25
+
+	// IP Layer Parameters per Interface
+	OptionInterfaceMTU              OptionCode = 26
+	OptionAllSubnetsAreLocal        OptionCode = 27
+	OptionBroadcastAddress          OptionCode = 28
+	OptionPerformMaskDiscovery      OptionCode = 29
+	OptionMaskSupplier              OptionCode = 30
+	OptionPerformRouterDiscovery    OptionCode = 31
+	OptionRouterSolicitationAddress OptionCode = 32
+	OptionStaticRoute               OptionCode = 33
+
+	// Link Layer Parameters per Interface
+	OptionTrailerEncapsulation  OptionCode = 34
+	OptionARPCacheTimeout       OptionCode = 35
+	OptionEthernetEncapsulation OptionCode = 36
+
+	// TCP Parameters
+	OptionTCPDefaultTTL        OptionCode = 37
+	OptionTCPKeepaliveInterval OptionCode = 38
+	OptionTCPKeepaliveGarbage  OptionCode = 39
+
+	// Application and Service Parameters
+	OptionNetworkInformationServiceDomain            OptionCode = 40
+	OptionNetworkInformationServers                  OptionCode = 41
+	OptionNetworkTimeProtocolServers                 OptionCode = 42
+	OptionVendorSpecificInformation                  OptionCode = 43
+	OptionNetBIOSOverTCPIPNameServer                 OptionCode = 44
+	OptionNetBIOSOverTCPIPDatagramDistributionServer OptionCode = 45
+	OptionNetBIOSOverTCPIPNodeType                   OptionCode = 46
+	OptionNetBIOSOverTCPIPScope                      OptionCode = 47
+	OptionXWindowSystemFontServer                    OptionCode = 48
+	OptionXWindowSystemDisplayManager                OptionCode = 49
+	OptionNetworkInformationServicePlusDomain        OptionCode = 64
+	OptionNetworkInformationServicePlusServers       OptionCode = 65
+	OptionMobileIPHomeAgent                          OptionCode = 68
+	OptionSimpleMailTransportProtocol                OptionCode = 69
+	OptionPostOfficeProtocolServer                   OptionCode = 70
+	OptionNetworkNewsTransportProtocol               OptionCode = 71
+	OptionDefaultWorldWideWebServer                  OptionCode = 72
+	OptionDefaultFingerServer                        OptionCode = 73
+	OptionDefaultInternetRelayChatServer             OptionCode = 74
+	OptionStreetTalkServer                           OptionCode = 75
+	OptionStreetTalkDirectoryAssistance              OptionCode = 76
+
+	// DHCP Extensions
+	OptionRequestedIPAddress     OptionCode = 50
+	OptionIPAddressLeaseTime     OptionCode = 51
+	OptionOverload               OptionCode = 52
+	OptionDHCPMessageType        OptionCode = 53
+	OptionServerIdentifier       OptionCode = 54
+	OptionParameterRequestList   OptionCode = 55
+	OptionMessage                OptionCode = 56
+	OptionMaximumDHCPMessageSize OptionCode = 57
+	OptionRenewalTimeValue       OptionCode = 58
+	OptionRebindingTimeValue     OptionCode = 59
+	OptionVendorClassIdentifier  OptionCode = 60
+	OptionClientIdentifier       OptionCode = 61
+
+	OptionTFTPServerName OptionCode = 66
+	OptionBootFileName   OptionCode = 67
+
+	OptionUserClass OptionCode = 77
+
+	OptionClientArchitecture OptionCode = 93
+
+	OptionTZPOSIXString    OptionCode = 100
+	OptionTZDatabaseString OptionCode = 101
+
+	OptionClasslessRouteFormat OptionCode = 121
+)

vendor/github.com/d2g/dhcp4/helpers.go

@@ -0,0 +1,58 @@
+package dhcp4
+
+import (
+	"encoding/binary"
+	"net"
+	"time"
+)
+
+// IPRange returns how many ips in the ip range from start to stop (inclusive)
+func IPRange(start, stop net.IP) int {
+	//return int(Uint([]byte(stop))-Uint([]byte(start))) + 1
+	return int(binary.BigEndian.Uint32(stop.To4())) - int(binary.BigEndian.Uint32(start.To4())) + 1
+}
+
+// IPAdd returns a copy of start + add.
+// IPAdd(net.IP{192,168,1,1},30) returns net.IP{192.168.1.31}
+func IPAdd(start net.IP, add int) net.IP { // IPv4 only
+	start = start.To4()
+	//v := Uvarint([]byte(start))
+	result := make(net.IP, 4)
+	binary.BigEndian.PutUint32(result, binary.BigEndian.Uint32(start)+uint32(add))
+	//PutUint([]byte(result), v+uint64(add))
+	return result
+}
+
+// IPLess returns where IP a is less than IP b.
+func IPLess(a, b net.IP) bool {
+	b = b.To4()
+	for i, ai := range a.To4() {
+		if ai != b[i] {
+			return ai < b[i]
+		}
+	}
+	return false
+}
+
+// IPInRange returns true if ip is between (inclusive) start and stop.
+func IPInRange(start, stop, ip net.IP) bool {
+	return !(IPLess(ip, start) || IPLess(stop, ip))
+}
+
+// OptionsLeaseTime - converts a time.Duration to a 4 byte slice, compatible
+// with OptionIPAddressLeaseTime.
+func OptionsLeaseTime(d time.Duration) []byte {
+	leaseBytes := make([]byte, 4)
+	binary.BigEndian.PutUint32(leaseBytes, uint32(d/time.Second))
+	//PutUvarint(leaseBytes, uint64(d/time.Second))
+	return leaseBytes
+}
+
+// JoinIPs returns a byte slice of IP addresses, one immediately after the other
+// This may be useful for creating multiple IP options such as OptionRouter.
+func JoinIPs(ips []net.IP) (b []byte) {
+	for _, v := range ips {
+		b = append(b, v.To4()...)
+	}
+	return
+}

vendor/github.com/d2g/dhcp4/option.go

@@ -0,0 +1,40 @@
+package dhcp4
+
+type OptionCode byte
+
+type Option struct {
+	Code  OptionCode
+	Value []byte
+}
+
+// Map of DHCP options
+type Options map[OptionCode][]byte
+
+// SelectOrderOrAll has same functionality as SelectOrder, except if the order
+// param is nil, whereby all options are added (in arbitary order).
+func (o Options) SelectOrderOrAll(order []byte) []Option {
+	if order == nil {
+		opts := make([]Option, 0, len(o))
+		for i, v := range o {
+			opts = append(opts, Option{Code: i, Value: v})
+		}
+		return opts
+	}
+	return o.SelectOrder(order)
+}
+
+// SelectOrder returns a slice of options ordered and selected by a byte array
+// usually defined by OptionParameterRequestList.  This result is expected to be
+// used in ReplyPacket()'s []Option parameter.
+func (o Options) SelectOrder(order []byte) []Option {
+	opts := make([]Option, 0, len(order))
+	for _, v := range order {
+		if data, ok := o[OptionCode(v)]; ok {
+			opts = append(opts, Option{Code: OptionCode(v), Value: data})
+		}
+	}
+	return opts
+}
+
+type OpCode byte
+type MessageType byte // Option 53

vendor/github.com/d2g/dhcp4/packet.go

@@ -0,0 +1,149 @@
+package dhcp4
+
+import (
+	"net"
+	"time"
+)
+
+// A DHCP packet
+type Packet []byte
+
+func (p Packet) OpCode() OpCode { return OpCode(p[0]) }
+func (p Packet) HType() byte    { return p[1] }
+func (p Packet) HLen() byte     { return p[2] }
+func (p Packet) Hops() byte     { return p[3] }
+func (p Packet) XId() []byte    { return p[4:8] }
+func (p Packet) Secs() []byte   { return p[8:10] } // Never Used?
+func (p Packet) Flags() []byte  { return p[10:12] }
+func (p Packet) CIAddr() net.IP { return net.IP(p[12:16]) }
+func (p Packet) YIAddr() net.IP { return net.IP(p[16:20]) }
+func (p Packet) SIAddr() net.IP { return net.IP(p[20:24]) }
+func (p Packet) GIAddr() net.IP { return net.IP(p[24:28]) }
+func (p Packet) CHAddr() net.HardwareAddr {
+	hLen := p.HLen()
+	if hLen > 16 { // Prevent chaddr exceeding p boundary
+		hLen = 16
+	}
+	return net.HardwareAddr(p[28 : 28+hLen]) // max endPos 44
+}
+
+// 192 bytes of zeros BOOTP legacy
+func (p Packet) Cookie() []byte { return p[236:240] }
+func (p Packet) Options() []byte {
+	if len(p) > 240 {
+		return p[240:]
+	}
+	return nil
+}
+
+func (p Packet) Broadcast() bool { return p.Flags()[0] > 127 }
+
+func (p Packet) SetBroadcast(broadcast bool) {
+	if p.Broadcast() != broadcast {
+		p.Flags()[0] ^= 128
+	}
+}
+
+func (p Packet) SetOpCode(c OpCode) { p[0] = byte(c) }
+func (p Packet) SetCHAddr(a net.HardwareAddr) {
+	copy(p[28:44], a)
+	p[2] = byte(len(a))
+}
+func (p Packet) SetHType(hType byte)     { p[1] = hType }
+func (p Packet) SetCookie(cookie []byte) { copy(p.Cookie(), cookie) }
+func (p Packet) SetHops(hops byte)       { p[3] = hops }
+func (p Packet) SetXId(xId []byte)       { copy(p.XId(), xId) }
+func (p Packet) SetSecs(secs []byte)     { copy(p.Secs(), secs) }
+func (p Packet) SetFlags(flags []byte)   { copy(p.Flags(), flags) }
+func (p Packet) SetCIAddr(ip net.IP)     { copy(p.CIAddr(), ip.To4()) }
+func (p Packet) SetYIAddr(ip net.IP)     { copy(p.YIAddr(), ip.To4()) }
+func (p Packet) SetSIAddr(ip net.IP)     { copy(p.SIAddr(), ip.To4()) }
+func (p Packet) SetGIAddr(ip net.IP)     { copy(p.GIAddr(), ip.To4()) }
+
+// Parses the packet's options into an Options map
+func (p Packet) ParseOptions() Options {
+	opts := p.Options()
+	options := make(Options, 10)
+	for len(opts) >= 2 && OptionCode(opts[0]) != End {
+		if OptionCode(opts[0]) == Pad {
+			opts = opts[1:]
+			continue
+		}
+		size := int(opts[1])
+		if len(opts) < 2+size {
+			break
+		}
+		options[OptionCode(opts[0])] = opts[2 : 2+size]
+		opts = opts[2+size:]
+	}
+	return options
+}
+
+func NewPacket(opCode OpCode) Packet {
+	p := make(Packet, 241)
+	p.SetOpCode(opCode)
+	p.SetHType(1) // Ethernet
+	p.SetCookie([]byte{99, 130, 83, 99})
+	p[240] = byte(End)
+	return p
+}
+
+// Appends a DHCP option to the end of a packet
+func (p *Packet) AddOption(o OptionCode, value []byte) {
+	*p = append((*p)[:len(*p)-1], []byte{byte(o), byte(len(value))}...) // Strip off End, Add OptionCode and Length
+	*p = append(*p, value...)                                           // Add Option Value
+	*p = append(*p, byte(End))                                          // Add on new End
+}
+
+// Removes all options from packet.
+func (p *Packet) StripOptions() {
+	*p = append((*p)[:240], byte(End))
+}
+
+// Creates a request packet that a Client would send to a server.
+func RequestPacket(mt MessageType, chAddr net.HardwareAddr, cIAddr net.IP, xId []byte, broadcast bool, options []Option) Packet {
+	p := NewPacket(BootRequest)
+	p.SetCHAddr(chAddr)
+	p.SetXId(xId)
+	if cIAddr != nil {
+		p.SetCIAddr(cIAddr)
+	}
+	p.SetBroadcast(broadcast)
+	p.AddOption(OptionDHCPMessageType, []byte{byte(mt)})
+	for _, o := range options {
+		p.AddOption(o.Code, o.Value)
+	}
+	p.PadToMinSize()
+	return p
+}
+
+// ReplyPacket creates a reply packet that a Server would send to a client.
+// It uses the req Packet param to copy across common/necessary fields to
+// associate the reply the request.
+func ReplyPacket(req Packet, mt MessageType, serverId, yIAddr net.IP, leaseDuration time.Duration, options []Option) Packet {
+	p := NewPacket(BootReply)
+	p.SetXId(req.XId())
+	p.SetFlags(req.Flags())
+	p.SetYIAddr(yIAddr)
+	p.SetGIAddr(req.GIAddr())
+	p.SetCHAddr(req.CHAddr())
+	p.SetSecs(req.Secs())
+	p.AddOption(OptionDHCPMessageType, []byte{byte(mt)})
+	p.AddOption(OptionServerIdentifier, []byte(serverId))
+	p.AddOption(OptionIPAddressLeaseTime, OptionsLeaseTime(leaseDuration))
+	for _, o := range options {
+		p.AddOption(o.Code, o.Value)
+	}
+	p.PadToMinSize()
+	return p
+}
+
+// PadToMinSize pads a packet so that when sent over UDP, the entire packet,
+// is 300 bytes (BOOTP min), to be compatible with really old devices.
+var padder [272]byte
+
+func (p *Packet) PadToMinSize() {
+	if n := len(*p); n < 272 {
+		*p = append(*p, padder[:272-n]...)
+	}
+}

vendor/github.com/d2g/dhcp4client/LICENSE

@@ -0,0 +1,354 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. “Contributor”
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. “Contributor Version”
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor’s Contribution.
+
+1.3. “Contribution”
+
+     means Covered Software of a particular Contributor.
+
+1.4. “Covered Software”
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. “Incompatible With Secondary Licenses”
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of version
+        1.1 or earlier of the License, but not also under the terms of a
+        Secondary License.
+
+1.6. “Executable Form”
+
+     means any form of the work other than Source Code Form.
+
+1.7. “Larger Work”
+
+     means a work that combines Covered Software with other material, in a separate
+     file or files, that is not Covered Software.
+
+1.8. “License”
+
+     means this document.
+
+1.9. “Licensable”
+
+     means having the right to grant, to the maximum extent possible, whether at the
+     time of the initial grant or subsequently, any and all of the rights conveyed by
+     this License.
+
+1.10. “Modifications”
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to, deletion
+        from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. “Patent Claims” of a Contributor
+
+      means any patent claim(s), including without limitation, method, process,
+      and apparatus claims, in any patent Licensable by such Contributor that
+      would be infringed, but for the grant of the License, by the making,
+      using, selling, offering for sale, having made, import, or transfer of
+      either its Contributions or its Contributor Version.
+
+1.12. “Secondary License”
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. “Source Code Form”
+
+      means the form of the work preferred for making modifications.
+
+1.14. “You” (or “Your”)
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, “You” includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, “control” means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or as
+        part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its Contributions
+        or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution become
+     effective for each Contribution on the date the Contributor first distributes
+     such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under this
+     License. No additional rights or licenses will be implied from the distribution
+     or licensing of Covered Software under this License. Notwithstanding Section
+     2.1(b) above, no patent license is granted by a Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party’s
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of its
+        Contributions.
+
+     This License does not grant any rights in the trademarks, service marks, or
+     logos of any Contributor (except as may be necessary to comply with the
+     notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this License
+     (see Section 10.2) or under the terms of a Secondary License (if permitted
+     under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its Contributions
+     are its original creation(s) or it has sufficient rights to grant the
+     rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under applicable
+     copyright doctrines of fair use, fair dealing, or other equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under the
+     terms of this License. You must inform recipients that the Source Code Form
+     of the Covered Software is governed by the terms of this License, and how
+     they can obtain a copy of this License. You may not attempt to alter or
+     restrict the recipients’ rights in the Source Code Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this License,
+        or sublicense it under different terms, provided that the license for
+        the Executable Form does not attempt to limit or alter the recipients’
+        rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for the
+     Covered Software. If the Larger Work is a combination of Covered Software
+     with a work governed by one or more Secondary Licenses, and the Covered
+     Software is not Incompatible With Secondary Licenses, this License permits
+     You to additionally distribute such Covered Software under the terms of
+     such Secondary License(s), so that the recipient of the Larger Work may, at
+     their option, further distribute the Covered Software under the terms of
+     either this License or such Secondary License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices (including
+     copyright notices, patent notices, disclaimers of warranty, or limitations
+     of liability) contained within the Source Code Form of the Covered
+     Software, except that You may alter any license notices to the extent
+     required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on behalf
+     of any Contributor. You must make it absolutely clear that any such
+     warranty, support, indemnity, or liability obligation is offered by You
+     alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute, judicial
+   order, or regulation then You must: (a) comply with the terms of this License
+   to the maximum extent possible; and (b) describe the limitations and the code
+   they affect. Such description must be placed in a text file included with all
+   distributions of the Covered Software under this License. Except to the
+   extent prohibited by statute or regulation, such description must be
+   sufficiently detailed for a recipient of ordinary skill to be able to
+   understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing basis,
+     if such Contributor fails to notify You of the non-compliance by some
+     reasonable means prior to 60 days after You have come back into compliance.
+     Moreover, Your grants from a particular Contributor are reinstated on an
+     ongoing basis if such Contributor notifies You of the non-compliance by
+     some reasonable means, this is the first time You have received notice of
+     non-compliance with this License from such Contributor, and You become
+     compliant prior to 30 days after Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions, counter-claims,
+     and cross-claims) alleging that a Contributor Version directly or
+     indirectly infringes any patent, then the rights granted to You by any and
+     all Contributors for the Covered Software under Section 2.1 of this License
+     shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an “as is” basis, without
+   warranty of any kind, either expressed, implied, or statutory, including,
+   without limitation, warranties that the Covered Software is free of defects,
+   merchantable, fit for a particular purpose or non-infringing. The entire
+   risk as to the quality and performance of the Covered Software is with You.
+   Should any Covered Software prove defective in any respect, You (not any
+   Contributor) assume the cost of any necessary servicing, repair, or
+   correction. This disclaimer of warranty constitutes an essential part of this
+   License. No use of  any Covered Software is authorized under this License
+   except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from such
+   party’s negligence to the extent applicable law prohibits such limitation.
+   Some jurisdictions do not allow the exclusion or limitation of incidental or
+   consequential damages, so this exclusion and limitation may not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts of
+   a jurisdiction where the defendant maintains its principal place of business
+   and such litigation shall be governed by laws of that jurisdiction, without
+   reference to its conflict-of-law provisions. Nothing in this Section shall
+   prevent a party’s ability to bring cross-claims or counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject matter
+   hereof. If any provision of this License is held to be unenforceable, such
+   provision shall be reformed only to the extent necessary to make it
+   enforceable. Any law or regulation which provides that the language of a
+   contract shall be construed against the drafter shall not be used to construe
+   this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version of
+      the License under which You originally received the Covered Software, or
+      under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a modified
+      version of this License if you rename the license and remove any
+      references to the name of the license steward (except to note that such
+      modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary Licenses
+      If You choose to distribute Source Code Form that is Incompatible With
+      Secondary Licenses under the terms of this version of the License, the
+      notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file, then
+You may include the notice in a location (such as a LICENSE file in a relevant
+directory) where a recipient would be likely to look for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - “Incompatible With Secondary Licenses” Notice
+
+      This Source Code Form is “Incompatible
+      With Secondary Licenses”, as defined by
+      the Mozilla Public License, v. 2.0.
+

vendor/github.com/d2g/dhcp4client/README.md

@@ -0,0 +1,8 @@
+dhcp4client [![GoDoc](https://godoc.org/github.com/d2g/dhcp4client?status.svg)](http://godoc.org/github.com/d2g/dhcp4client) [![Coverage Status](https://coveralls.io/repos/d2g/dhcp4client/badge.svg?branch=HEAD)](https://coveralls.io/r/d2g/dhcp4client?branch=HEAD) [![Codeship Status for d2g/dhcp4client](https://codeship.com/projects/d75d9860-b364-0132-bc79-7e1d8cf367b9/status?branch=master)](https://codeship.com/projects/70187)
+===========
+
+DHCP Client
+
+
+###### Thanks to:
+@eyakubovich For AF_PACKET support.

vendor/github.com/d2g/dhcp4client/client.go

@@ -0,0 +1,366 @@
+package dhcp4client
+
+import (
+	"bytes"
+	"crypto/rand"
+	"net"
+	"time"
+
+	"github.com/d2g/dhcp4"
+)
+
+const (
+	MaxDHCPLen = 576
+)
+
+type Client struct {
+	hardwareAddr  net.HardwareAddr //The HardwareAddr to send in the request.
+	ignoreServers []net.IP         //List of Servers to Ignore requests from.
+	timeout       time.Duration    //Time before we timeout.
+	broadcast     bool             //Set the Bcast flag in BOOTP Flags
+	connection    connection       //The Connection Method to use
+}
+
+/*
+ * Abstracts the type of underlying socket used
+ */
+type connection interface {
+	Close() error
+	Write(packet []byte) error
+	ReadFrom() ([]byte, net.IP, error)
+	SetReadTimeout(t time.Duration) error
+}
+
+func New(options ...func(*Client) error) (*Client, error) {
+	c := Client{
+		timeout:   time.Second * 10,
+		broadcast: true,
+	}
+
+	err := c.SetOption(options...)
+	if err != nil {
+		return nil, err
+	}
+
+	//if connection hasn't been set as an option create the default.
+	if c.connection == nil {
+		conn, err := NewInetSock()
+		if err != nil {
+			return nil, err
+		}
+		c.connection = conn
+	}
+
+	return &c, nil
+}
+
+func (c *Client) SetOption(options ...func(*Client) error) error {
+	for _, opt := range options {
+		if err := opt(c); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func Timeout(t time.Duration) func(*Client) error {
+	return func(c *Client) error {
+		c.timeout = t
+		return nil
+	}
+}
+
+func IgnoreServers(s []net.IP) func(*Client) error {
+	return func(c *Client) error {
+		c.ignoreServers = s
+		return nil
+	}
+}
+
+func HardwareAddr(h net.HardwareAddr) func(*Client) error {
+	return func(c *Client) error {
+		c.hardwareAddr = h
+		return nil
+	}
+}
+
+func Broadcast(b bool) func(*Client) error {
+	return func(c *Client) error {
+		c.broadcast = b
+		return nil
+	}
+}
+
+func Connection(conn connection) func(*Client) error {
+	return func(c *Client) error {
+		c.connection = conn
+		return nil
+	}
+}
+
+/*
+ * Close Connections
+ */
+func (c *Client) Close() error {
+	if c.connection != nil {
+		return c.connection.Close()
+	}
+	return nil
+}
+
+/*
+ * Send the Discovery Packet to the Broadcast Channel
+ */
+func (c *Client) SendDiscoverPacket() (dhcp4.Packet, error) {
+	discoveryPacket := c.DiscoverPacket()
+	discoveryPacket.PadToMinSize()
+
+	return discoveryPacket, c.SendPacket(discoveryPacket)
+}
+
+/*
+ * Retreive Offer...
+ * Wait for the offer for a specific Discovery Packet.
+ */
+func (c *Client) GetOffer(discoverPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	for {
+		c.connection.SetReadTimeout(c.timeout)
+		readBuffer, source, err := c.connection.ReadFrom()
+		if err != nil {
+			return dhcp4.Packet{}, err
+		}
+
+		offerPacket := dhcp4.Packet(readBuffer)
+		offerPacketOptions := offerPacket.ParseOptions()
+
+		// Ignore Servers in my Ignore list
+		for _, ignoreServer := range c.ignoreServers {
+			if source.Equal(ignoreServer) {
+				continue
+			}
+
+			if offerPacket.SIAddr().Equal(ignoreServer) {
+				continue
+			}
+		}
+
+		if len(offerPacketOptions[dhcp4.OptionDHCPMessageType]) < 1 || dhcp4.MessageType(offerPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.Offer || !bytes.Equal(discoverPacket.XId(), offerPacket.XId()) {
+			continue
+		}
+
+		return offerPacket, nil
+	}
+
+}
+
+/*
+ * Send Request Based On the offer Received.
+ */
+func (c *Client) SendRequest(offerPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	requestPacket := c.RequestPacket(offerPacket)
+	requestPacket.PadToMinSize()
+
+	return requestPacket, c.SendPacket(requestPacket)
+}
+
+/*
+ * Retreive Acknowledgement
+ * Wait for the offer for a specific Request Packet.
+ */
+func (c *Client) GetAcknowledgement(requestPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	for {
+		c.connection.SetReadTimeout(c.timeout)
+		readBuffer, source, err := c.connection.ReadFrom()
+		if err != nil {
+			return dhcp4.Packet{}, err
+		}
+
+		acknowledgementPacket := dhcp4.Packet(readBuffer)
+		acknowledgementPacketOptions := acknowledgementPacket.ParseOptions()
+
+		// Ignore Servers in my Ignore list
+		for _, ignoreServer := range c.ignoreServers {
+			if source.Equal(ignoreServer) {
+				continue
+			}
+
+			if acknowledgementPacket.SIAddr().Equal(ignoreServer) {
+				continue
+			}
+		}
+
+		if !bytes.Equal(requestPacket.XId(), acknowledgementPacket.XId()) || len(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType]) < 1 || (dhcp4.MessageType(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK && dhcp4.MessageType(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.NAK) {
+			continue
+		}
+
+		return acknowledgementPacket, nil
+	}
+}
+
+/*
+ * Send a DHCP Packet.
+ */
+func (c *Client) SendPacket(packet dhcp4.Packet) error {
+	return c.connection.Write(packet)
+}
+
+/*
+ * Create Discover Packet
+ */
+func (c *Client) DiscoverPacket() dhcp4.Packet {
+	messageid := make([]byte, 4)
+	if _, err := rand.Read(messageid); err != nil {
+		panic(err)
+	}
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(c.hardwareAddr)
+	packet.SetXId(messageid)
+	packet.SetBroadcast(c.broadcast)
+
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Discover)})
+	//packet.PadToMinSize()
+	return packet
+}
+
+/*
+ * Create Request Packet
+ */
+func (c *Client) RequestPacket(offerPacket *dhcp4.Packet) dhcp4.Packet {
+	offerOptions := offerPacket.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(c.hardwareAddr)
+
+	packet.SetXId(offerPacket.XId())
+	packet.SetCIAddr(offerPacket.CIAddr())
+	packet.SetSIAddr(offerPacket.SIAddr())
+
+	packet.SetBroadcast(c.broadcast)
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Request)})
+	packet.AddOption(dhcp4.OptionRequestedIPAddress, (offerPacket.YIAddr()).To4())
+	packet.AddOption(dhcp4.OptionServerIdentifier, offerOptions[dhcp4.OptionServerIdentifier])
+
+	//packet.PadToMinSize()
+	return packet
+}
+
+/*
+ * Create Request Packet For a Renew
+ */
+func (c *Client) RenewalRequestPacket(acknowledgement *dhcp4.Packet) dhcp4.Packet {
+	messageid := make([]byte, 4)
+	if _, err := rand.Read(messageid); err != nil {
+		panic(err)
+	}
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(acknowledgement.CHAddr())
+
+	packet.SetXId(messageid)
+	packet.SetCIAddr(acknowledgement.YIAddr())
+	packet.SetSIAddr(acknowledgement.SIAddr())
+
+	packet.SetBroadcast(c.broadcast)
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Request)})
+	packet.AddOption(dhcp4.OptionRequestedIPAddress, (acknowledgement.YIAddr()).To4())
+	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])
+
+	//packet.PadToMinSize()
+	return packet
+}
+
+/*
+ * Create Release Packet For a Release
+ */
+func (c *Client) ReleasePacket(acknowledgement *dhcp4.Packet) dhcp4.Packet {
+	messageid := make([]byte, 4)
+	if _, err := rand.Read(messageid); err != nil {
+		panic(err)
+	}
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(acknowledgement.CHAddr())
+
+	packet.SetXId(messageid)
+	packet.SetCIAddr(acknowledgement.YIAddr())
+
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Release)})
+	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])
+
+	//packet.PadToMinSize()
+	return packet
+}
+
+/*
+ * Lets do a Full DHCP Request.
+ */
+func (c *Client) Request() (bool, dhcp4.Packet, error) {
+	discoveryPacket, err := c.SendDiscoverPacket()
+	if err != nil {
+		return false, discoveryPacket, err
+	}
+
+	offerPacket, err := c.GetOffer(&discoveryPacket)
+	if err != nil {
+		return false, offerPacket, err
+	}
+
+	requestPacket, err := c.SendRequest(&offerPacket)
+	if err != nil {
+		return false, requestPacket, err
+	}
+
+	acknowledgement, err := c.GetAcknowledgement(&requestPacket)
+	if err != nil {
+		return false, acknowledgement, err
+	}
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+	if dhcp4.MessageType(acknowledgementOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK {
+		return false, acknowledgement, nil
+	}
+
+	return true, acknowledgement, nil
+}
+
+/*
+ * Renew a lease backed on the Acknowledgement Packet.
+ * Returns Sucessfull, The AcknoledgementPacket, Any Errors
+ */
+func (c *Client) Renew(acknowledgement dhcp4.Packet) (bool, dhcp4.Packet, error) {
+	renewRequest := c.RenewalRequestPacket(&acknowledgement)
+	renewRequest.PadToMinSize()
+
+	err := c.SendPacket(renewRequest)
+	if err != nil {
+		return false, renewRequest, err
+	}
+
+	newAcknowledgement, err := c.GetAcknowledgement(&renewRequest)
+	if err != nil {
+		return false, newAcknowledgement, err
+	}
+
+	newAcknowledgementOptions := newAcknowledgement.ParseOptions()
+	if dhcp4.MessageType(newAcknowledgementOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK {
+		return false, newAcknowledgement, nil
+	}
+
+	return true, newAcknowledgement, nil
+}
+
+/*
+ * Release a lease backed on the Acknowledgement Packet.
+ * Returns Any Errors
+ */
+func (c *Client) Release(acknowledgement dhcp4.Packet) error {
+	release := c.ReleasePacket(&acknowledgement)
+	release.PadToMinSize()
+
+	return c.SendPacket(release)
+}

vendor/github.com/d2g/dhcp4client/inetsock.go

@@ -0,0 +1,75 @@
+package dhcp4client
+
+import (
+	"net"
+	"time"
+)
+
+type inetSock struct {
+	*net.UDPConn
+
+	laddr net.UDPAddr
+	raddr net.UDPAddr
+}
+
+func NewInetSock(options ...func(*inetSock) error) (*inetSock, error) {
+	c := &inetSock{
+		laddr: net.UDPAddr{IP: net.IPv4(0, 0, 0, 0), Port: 68},
+		raddr: net.UDPAddr{IP: net.IPv4bcast, Port: 67},
+	}
+
+	err := c.setOption(options...)
+	if err != nil {
+		return nil, err
+	}
+
+	conn, err := net.ListenUDP("udp4", &c.laddr)
+	if err != nil {
+		return nil, err
+	}
+
+	c.UDPConn = conn
+	return c, err
+}
+
+func (c *inetSock) setOption(options ...func(*inetSock) error) error {
+	for _, opt := range options {
+		if err := opt(c); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func SetLocalAddr(l net.UDPAddr) func(*inetSock) error {
+	return func(c *inetSock) error {
+		c.laddr = l
+		return nil
+	}
+}
+
+func SetRemoteAddr(r net.UDPAddr) func(*inetSock) error {
+	return func(c *inetSock) error {
+		c.raddr = r
+		return nil
+	}
+}
+
+func (c *inetSock) Write(packet []byte) error {
+	_, err := c.WriteToUDP(packet, &c.raddr)
+	return err
+}
+
+func (c *inetSock) ReadFrom() ([]byte, net.IP, error) {
+	readBuffer := make([]byte, MaxDHCPLen)
+	n, source, err := c.ReadFromUDP(readBuffer)
+	if source != nil {
+		return readBuffer[:n], source.IP, err
+	} else {
+		return readBuffer[:n], net.IP{}, err
+	}
+}
+
+func (c *inetSock) SetReadTimeout(t time.Duration) error {
+	return c.SetReadDeadline(time.Now().Add(t))
+}

vendor/github.com/d2g/dhcp4client/init.go

@@ -0,0 +1,10 @@
+package dhcp4client
+
+import (
+	"math/rand"
+	"time"
+)
+
+func init() {
+	rand.Seed(time.Now().Unix())
+}

vendor/github.com/d2g/dhcp4client/pktsock_linux.go

@@ -0,0 +1,147 @@
+package dhcp4client
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"net"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+const (
+	minIPHdrLen = 20
+	maxIPHdrLen = 60
+	udpHdrLen   = 8
+	ip4Ver      = 0x40
+	ttl         = 16
+	srcPort     = 68
+	dstPort     = 67
+)
+
+var (
+	bcastMAC = []byte{255, 255, 255, 255, 255, 255}
+)
+
+// abstracts AF_PACKET
+type packetSock struct {
+	fd      int
+	ifindex int
+}
+
+func NewPacketSock(ifindex int) (*packetSock, error) {
+	fd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_DGRAM, int(swap16(unix.ETH_P_IP)))
+	if err != nil {
+		return nil, err
+	}
+
+	addr := unix.SockaddrLinklayer{
+		Ifindex:  ifindex,
+		Protocol: swap16(unix.ETH_P_IP),
+	}
+
+	if err = unix.Bind(fd, &addr); err != nil {
+		return nil, err
+	}
+
+	return &packetSock{
+		fd:      fd,
+		ifindex: ifindex,
+	}, nil
+}
+
+func (pc *packetSock) Close() error {
+	return unix.Close(pc.fd)
+}
+
+func (pc *packetSock) Write(packet []byte) error {
+	lladdr := unix.SockaddrLinklayer{
+		Ifindex:  pc.ifindex,
+		Protocol: swap16(unix.ETH_P_IP),
+		Halen:    uint8(len(bcastMAC)),
+	}
+	copy(lladdr.Addr[:], bcastMAC)
+
+	pkt := make([]byte, minIPHdrLen+udpHdrLen+len(packet))
+
+	fillIPHdr(pkt[0:minIPHdrLen], udpHdrLen+uint16(len(packet)))
+	fillUDPHdr(pkt[minIPHdrLen:minIPHdrLen+udpHdrLen], uint16(len(packet)))
+
+	// payload
+	copy(pkt[minIPHdrLen+udpHdrLen:len(pkt)], packet)
+
+	return unix.Sendto(pc.fd, pkt, 0, &lladdr)
+}
+
+func (pc *packetSock) ReadFrom() ([]byte, net.IP, error) {
+	pkt := make([]byte, maxIPHdrLen+udpHdrLen+MaxDHCPLen)
+	n, _, err := unix.Recvfrom(pc.fd, pkt, 0)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// IP hdr len
+	ihl := int(pkt[0]&0x0F) * 4
+	// Source IP address
+	src := net.IP(pkt[12:16])
+
+	return pkt[ihl+udpHdrLen : n], src, nil
+}
+
+func (pc *packetSock) SetReadTimeout(t time.Duration) error {
+
+	tv := unix.NsecToTimeval(t.Nanoseconds())
+	return unix.SetsockoptTimeval(pc.fd, unix.SOL_SOCKET, unix.SO_RCVTIMEO, &tv)
+}
+
+// compute's 1's complement checksum
+func chksum(p []byte, csum []byte) {
+	cklen := len(p)
+	s := uint32(0)
+	for i := 0; i < (cklen - 1); i += 2 {
+		s += uint32(p[i+1])<<8 | uint32(p[i])
+	}
+	if cklen&1 == 1 {
+		s += uint32(p[cklen-1])
+	}
+	s = (s >> 16) + (s & 0xffff)
+	s = s + (s >> 16)
+	s = ^s
+
+	csum[0] = uint8(s & 0xff)
+	csum[1] = uint8(s >> 8)
+}
+
+func fillIPHdr(hdr []byte, payloadLen uint16) {
+	// version + IHL
+	hdr[0] = ip4Ver | (minIPHdrLen / 4)
+	// total length
+	binary.BigEndian.PutUint16(hdr[2:4], uint16(len(hdr))+payloadLen)
+	// identification
+	if _, err := rand.Read(hdr[4:5]); err != nil {
+		panic(err)
+	}
+	// TTL
+	hdr[8] = 16
+	// Protocol
+	hdr[9] = unix.IPPROTO_UDP
+	// dst IP
+	copy(hdr[16:20], net.IPv4bcast.To4())
+	// compute IP hdr checksum
+	chksum(hdr[0:len(hdr)], hdr[10:12])
+}
+
+func fillUDPHdr(hdr []byte, payloadLen uint16) {
+	// src port
+	binary.BigEndian.PutUint16(hdr[0:2], srcPort)
+	// dest port
+	binary.BigEndian.PutUint16(hdr[2:4], dstPort)
+	// length
+	binary.BigEndian.PutUint16(hdr[4:6], udpHdrLen+payloadLen)
+}
+
+func swap16(x uint16) uint16 {
+	var b [2]byte
+	binary.BigEndian.PutUint16(b[:], x)
+	return binary.LittleEndian.Uint16(b[:])
+}