├── .gitignore ├── Gopkg.lock ├── Gopkg.toml ├── LICENSE ├── README.md ├── dhcp.go ├── etcd.go ├── main.go └── storage.go /.gitignore: -------------------------------------------------------------------------------- 1 | vendor 2 | -------------------------------------------------------------------------------- /Gopkg.lock: -------------------------------------------------------------------------------- 1 | # This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'. 2 | 3 | 4 | [[projects]] 5 | branch = "master" 6 | name = "github.com/beorn7/perks" 7 | packages = ["quantile"] 8 | revision = "4c0e84591b9aa9e6dcfdf3e020114cd81f89d5f9" 9 | 10 | [[projects]] 11 | branch = "master" 12 | name = "github.com/coreos/etcd" 13 | packages = ["auth/authpb","clientv3","etcdserver/api/v3rpc/rpctypes","etcdserver/etcdserverpb","mvcc/mvccpb"] 14 | revision = "9ce7bb6a1c15bcffdd011a571dc686e71aabc314" 15 | 16 | [[projects]] 17 | branch = "master" 18 | name = "github.com/golang/glog" 19 | packages = ["."] 20 | revision = "23def4e6c14b4da8ac2ed8007337bc5eb5007998" 21 | 22 | [[projects]] 23 | branch = "master" 24 | name = "github.com/golang/protobuf" 25 | packages = ["proto","ptypes/any"] 26 | revision = "0a4f71a498b7c4812f64969510bcb4eca251e33a" 27 | 28 | [[projects]] 29 | branch = "master" 30 | name = "github.com/krolaw/dhcp4" 31 | packages = ["."] 32 | revision = "f61f734b73027e29f7fa2ed623f2ed85a7ef08fa" 33 | 34 | [[projects]] 35 | name = "github.com/matttproud/golang_protobuf_extensions" 36 | packages = ["pbutil"] 37 | revision = "3247c84500bff8d9fb6d579d800f20b3e091582c" 38 | version = "v1.0.0" 39 | 40 | [[projects]] 41 | name = "github.com/pkg/errors" 42 | packages = ["."] 43 | revision = "645ef00459ed84a119197bfb8d8205042c6df63d" 44 | version = "v0.8.0" 45 | 46 | [[projects]] 47 | name = "github.com/prometheus/client_golang" 48 | packages = ["prometheus","prometheus/promhttp"] 49 | revision = "c5b7fccd204277076155f10851dad72b76a49317" 50 | version = "v0.8.0" 51 | 52 | [[projects]] 53 | branch = "master" 54 | name = "github.com/prometheus/client_model" 55 | packages = ["go"] 56 | revision = "6f3806018612930941127f2a7c6c453ba2c527d2" 57 | 58 | [[projects]] 59 | branch = "master" 60 | name = "github.com/prometheus/common" 61 | packages = ["expfmt","internal/bitbucket.org/ww/goautoneg","model"] 62 | revision = "3e6a7635bac6573d43f49f97b47eb9bda195dba8" 63 | 64 | [[projects]] 65 | branch = "master" 66 | name = "github.com/prometheus/procfs" 67 | packages = [".","xfs"] 68 | revision = "e645f4e5aaa8506fc71d6edbc5c4ff02c04c46f2" 69 | 70 | [[projects]] 71 | branch = "master" 72 | name = "golang.org/x/net" 73 | packages = ["bpf","context","http2","http2/hpack","idna","internal/iana","internal/socket","internal/timeseries","ipv4","lex/httplex","trace"] 74 | revision = "b3756b4b77d7b13260a0a2ec658753cf48922eac" 75 | 76 | [[projects]] 77 | branch = "master" 78 | name = "golang.org/x/sync" 79 | packages = ["errgroup"] 80 | revision = "f52d1811a62927559de87708c8913c1650ce4f26" 81 | 82 | [[projects]] 83 | branch = "master" 84 | name = "golang.org/x/text" 85 | packages = ["internal/gen","internal/triegen","internal/ucd","secure/bidirule","transform","unicode/bidi","unicode/cldr","unicode/norm","unicode/rangetable"] 86 | revision = "836efe42bb4aa16aaa17b9c155d8813d336ed720" 87 | 88 | [[projects]] 89 | branch = "master" 90 | name = "google.golang.org/genproto" 91 | packages = ["googleapis/rpc/status"] 92 | revision = "b0a3dcfcd1a9bd48e63634bd8802960804cf8315" 93 | 94 | [[projects]] 95 | name = "google.golang.org/grpc" 96 | packages = [".","codes","credentials","grpclb/grpc_lb_v1","grpclog","internal","keepalive","metadata","naming","peer","stats","status","tap","transport"] 97 | revision = "b15215fb911b24a5d61d57feec4233d610530464" 98 | version = "v1.4.2" 99 | 100 | [solve-meta] 101 | analyzer-name = "dep" 102 | analyzer-version = 1 103 | inputs-digest = "8b2bcce0943c4c2ad7c85e8f939d84b4d1b4ae56c3728451159a65430e670f50" 104 | solver-name = "gps-cdcl" 105 | solver-version = 1 106 | -------------------------------------------------------------------------------- /Gopkg.toml: -------------------------------------------------------------------------------- 1 | 2 | # Gopkg.toml example 3 | # 4 | # Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md 5 | # for detailed Gopkg.toml documentation. 6 | # 7 | # required = ["github.com/user/thing/cmd/thing"] 8 | # ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"] 9 | # 10 | # [[constraint]] 11 | # name = "github.com/user/project" 12 | # version = "1.0.0" 13 | # 14 | # [[constraint]] 15 | # name = "github.com/user/project2" 16 | # branch = "dev" 17 | # source = "github.com/myfork/project2" 18 | # 19 | # [[override]] 20 | # name = "github.com/x/y" 21 | # version = "2.4.0" 22 | 23 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | {one line to give the program's name and a brief idea of what it does.} 635 | Copyright (C) {year} {name of author} 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | {project} Copyright (C) {year} {fullname} 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # etcDHCP 2 | 3 | Ever wondered what was going on with your DHCP leases? Not comfortable looking 4 | at `/var/lib/dhcp/dhcp.leases`? Feel like your DHCP should be a bit higher 5 | availablilty, and a little bit more stateless? Prefer GRPC to ARP? Want to make 6 | your DHCP server a legitimate microservice? Is dhcpd not cloud native enough for 7 | you? 8 | 9 | If any of that applies to you, I may have the DHCP server of your dreams, right 10 | here. etcDHCP is the worlds first strongly consistent distributed DHCP server 11 | (in the absence of any other google results), using CoreOS's etcd to ensure that 12 | whatever happens, your leases will remain available. Well, at least, in 49% of 13 | cases. Assuming all cases have an independent effect on your etcd nodes. 14 | 15 | ## Install 16 | 17 | If you've never built a Go project before, I'm sorry. 18 | 19 | ``` 20 | $ go get -u github.com/golang/dep/cmd/dep 21 | $ go get github.com/lclarkmichalek/etcdhcp 22 | $ cd $GOPATH/src/github.com/lclarkmichalek/etcdhcp 23 | $ dep ensure 24 | $ go install 25 | ``` 26 | 27 | ## Setup 28 | 29 | ### etcd 30 | 31 | etcDHCP requires etcd, surprisingly enough. Notably, it requires at least 32 | version 3.3.0. However, this version doesn't actually exist yet, so just run 33 | master. 34 | 35 | ### etcDHCP 36 | 37 | Because running `--help` is hard, I guess. 38 | 39 | ``` 40 | $ etcdhcp \ 41 | -etcd.discovery.endpoints localhost:2379 \ 42 | -v=2 \ 43 | -dhcp.router 10.6.9.1 \ 44 | -dhcp.dns 10.6.9.1 \ 45 | -dhcp.server-if wlan0_ap \ 46 | -dhcp.server-ip 10.6.9.1 \ 47 | -dhcp.subnet-mask 255.255.255.0 \ 48 | -dhcp.issue-from 10.6.9.10 \ 49 | -dhcp.issue-to 10.6.9.100 \ 50 | I0717 17:39:22.076564 25273 main.go:51] starting dhcp listener 51 | I0717 17:39:22.076564 25273 main.go:45] starting admin server on :9842 52 | ``` 53 | 54 | There are tons of etcd options, most of which will probably be useless, as if 55 | you're not yet running a DHCP server, there's a decent chance that SRV record 56 | resolution won't be working. Notably missing is discovery via MAC address. Now 57 | that'd be fun.. 58 | 59 | The DHCP options should be, um, well, let's hope you've configured a DHCP server 60 | before. Plenty of things aren't supported, but you can certainly get a lot of 61 | stuff working by writing to etcd directly. 62 | 63 | ## Operating concerns 64 | 65 | Like all ~~good~~ cloud native software, etcDHCP exports Prometheus metrics on 66 | `:9842`. There's also pprof endpoints exposed. I didn't implement a readiness or 67 | liveness endpoint, as um, well they'd be a bit pointless. Also no graceful 68 | shutdowns because github.com/krolaw/dhcp4 doesn't support context yet. 69 | 70 | ## etcd structure 71 | 72 | ``` 73 | $ ./etcdctl get etcdhcp::ips::leased::10.6.9.99 74 | etcdhcp::ips::leased::10.6.9.99 75 | 5c:96:56:a4:be:eb 76 | $ ./etcdctl get etcdhcp::ips::free::10.6.9.94 77 | etcdhcp::ips::free::10.6.9.94 78 | 10.6.9.94 79 | $ ./etcdctl get etcdhcp::nics::leased::08:9e:08:b5:af:01 80 | etcdhcp::nics::leased::08:9e:08:b5:af:01 81 | 10.6.9.97 82 | ``` 83 | 84 | Want to add more IPs? Either restart the dhcp server with a different range, 85 | or.. 86 | 87 | ``` 88 | $ for i in `seq 200 220`; do ./etcdctl put etcdhcp::ips::free::10.6.9.$i 10.6.9.$i; done 89 | ``` 90 | 91 | Warning: IPs that aren't in the range of a running server will gradually be 92 | phased out. They'll be removed when they are picked up by a client, and that 93 | client allows the lease to expire. 94 | 95 | Want to react to a device connecting? Watch the nic entry for the device's MAC 96 | address: 97 | 98 | ``` 99 | $ etcdctl watch etcdhcp::nics::leased::08:9e:08:b5:af:01 100 | ``` 101 | 102 | Beware that renewals will cause updates to the nic key (updating/changing the 103 | lease to one with a more recent expiry). make sure to watch for 104 | creation/deletion events only. 105 | 106 | Want to give a specific device a specific ip? Just associate the two, and any 107 | DHCP discovery request will pick up the existing association. 108 | 109 | ``` 110 | $ etcdctl put etcdhcp::nics::leased::08:9e:08:b5:af:01 10.6.9.2 111 | $ etcdctl put etcdhcp::ips::leased::10.6.9.2 08:9e:08:b5:af:01 112 | $ etcdctl delete etcdhcp::ips::free::10.6.9.2 113 | ``` 114 | 115 | Warning: the leased keys have ttls set when a lease is issued, so you should set 116 | this up in a cron or something. 117 | -------------------------------------------------------------------------------- /dhcp.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "context" 5 | "net" 6 | "time" 7 | 8 | etcd "github.com/coreos/etcd/clientv3" 9 | "github.com/golang/glog" 10 | dhcp "github.com/krolaw/dhcp4" 11 | "github.com/pkg/errors" 12 | ) 13 | 14 | type DHCPHandler struct { 15 | client *etcd.Client 16 | prefix string 17 | timeout time.Duration 18 | 19 | ip net.IP 20 | options dhcp.Options 21 | start net.IP 22 | end net.IP 23 | leaseDuration time.Duration 24 | } 25 | 26 | func (h *DHCPHandler) ServeDHCP(p dhcp.Packet, msgType dhcp.MessageType, options dhcp.Options) dhcp.Packet { 27 | ctx, cancel := context.WithTimeout(context.Background(), h.timeout) 28 | defer cancel() 29 | 30 | switch msgType { 31 | case dhcp.Discover: 32 | glog.Infof("handling discover") 33 | nic := p.CHAddr().String() 34 | ip, err := h.handleDiscover(ctx, nic) 35 | if err != nil { 36 | glog.Errorf("failed to respond to discover request: %v", err) 37 | return nil 38 | } 39 | glog.Infof("offering %v to %v", ip, nic) 40 | 41 | return dhcp.ReplyPacket(p, dhcp.Offer, h.ip, ip, h.leaseDuration, 42 | h.options.SelectOrderOrAll(options[dhcp.OptionParameterRequestList])) 43 | 44 | case dhcp.Request: 45 | if server, ok := options[dhcp.OptionServerIdentifier]; ok && !net.IP(server).Equal(h.ip) { 46 | return nil // Message not for this dhcp server 47 | } 48 | reqIP := net.IP(options[dhcp.OptionRequestedIPAddress]) 49 | if reqIP == nil { 50 | reqIP = net.IP(p.CIAddr()) 51 | } 52 | 53 | ip, err := h.handleRequest(ctx, reqIP, p.CHAddr().String()) 54 | if err != nil { 55 | glog.Errorf("could not lease: %v", err) 56 | return dhcp.ReplyPacket(p, dhcp.NAK, h.ip, nil, 0, nil) 57 | } 58 | glog.Infof("leased %v to %v", reqIP, p.CHAddr().String()) 59 | return dhcp.ReplyPacket(p, dhcp.ACK, h.ip, ip, h.leaseDuration, 60 | h.options.SelectOrderOrAll(options[dhcp.OptionParameterRequestList])) 61 | 62 | case dhcp.Release, dhcp.Decline: 63 | err := h.revokeLease(ctx, p.CHAddr().String()) 64 | if err != nil { 65 | glog.Errorf("could not revoke lease for %v: %v", p.CHAddr().String(), err) 66 | } 67 | } 68 | return nil 69 | } 70 | 71 | func (h *DHCPHandler) handleDiscover(ctx context.Context, nic string) (net.IP, error) { 72 | leased, err := h.nicLeasedIP(ctx, nic) 73 | if err != nil { 74 | return nil, errors.Wrap(err, "could not lookup existing nic lease") 75 | } 76 | if leased != nil { 77 | glog.Infof("found previous lease for %v", nic) 78 | return leased, nil 79 | } 80 | new, err := h.freeIP(ctx) 81 | if err != nil { 82 | return nil, errors.Wrap(err, "could not find next free ip") 83 | } 84 | return new, nil 85 | } 86 | 87 | func (h *DHCPHandler) handleRequest(ctx context.Context, ip net.IP, nic string) (net.IP, error) { 88 | glog.Infof("handling request for %v from %v", ip, nic) 89 | if len(ip) != 4 || ip.Equal(net.IPv4zero) { 90 | return nil, errors.New("invalid ip requested") 91 | } 92 | 93 | err := h.leaseIP(ctx, ip, nic, h.leaseDuration*2) 94 | if err != nil { 95 | return nil, errors.Wrap(err, "could not update lease") 96 | } 97 | return ip, nil 98 | } 99 | -------------------------------------------------------------------------------- /etcd.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "context" 5 | "crypto/tls" 6 | "crypto/x509" 7 | "flag" 8 | "fmt" 9 | "io/ioutil" 10 | "net" 11 | "net/url" 12 | "strings" 13 | "time" 14 | 15 | etcd "github.com/coreos/etcd/clientv3" 16 | "github.com/golang/glog" 17 | "github.com/pkg/errors" 18 | ) 19 | 20 | var ( 21 | etcdDiscoverySRV = flag.String("etcd.discovery.srv", "", "SRV record to use to discover ETCD") 22 | etcdDiscoveryEndpoints = flag.String("etcd.discovery.endpoints", "", "endpoint list to use to discover ETCD") 23 | etcdAuthUsername = flag.String("etcd.auth.username", "", "username used to auth with ETCD") 24 | etcdAuthPassword = flag.String("etcd.auth.password", "", "password used to auth with ETCD") 25 | etcdAuthCA = flag.String("etcd.auth.ca", "", "CA certificate used to connect to ETCD") 26 | etcdAuthCert = flag.String("etcd.auth.cert", "", "client certificate used to connect to ETCD") 27 | etcdAuthKey = flag.String("etcd.auth.key", "", "client key used to connect to ETCD") 28 | etcdPrefix = flag.String("etcd.prefix", "etcdhcp::", "prefix to use when calculating ETCD keys") 29 | ) 30 | 31 | func NewETCDStore(ctx context.Context) (*etcd.Client, error) { 32 | conf, err := etcdConfig() 33 | if err != nil { 34 | return nil, errors.WithMessage(err, "could not load etcd config") 35 | } 36 | 37 | client, err := etcd.New(conf) 38 | if err != nil { 39 | return nil, errors.Wrap(err, "could not create etcd client") 40 | } 41 | 42 | err = client.Sync(ctx) 43 | if err != nil { 44 | return nil, errors.Wrap(err, "could not perform initial etcd endpoint sync") 45 | } 46 | 47 | go func() { 48 | for ctx.Err() == nil { 49 | func() { 50 | ctx, cancel := context.WithTimeout(ctx, time.Second*30) 51 | defer cancel() 52 | 53 | err := client.Sync(ctx) 54 | if err != nil { 55 | glog.Errorf("failed to sync etcd endpoints: %v", err) 56 | } else { 57 | glog.V(4).Infof("synced etcd endpoint list") 58 | } 59 | }() 60 | 61 | select { 62 | case <-time.After(time.Second * 60): 63 | case <-ctx.Done(): 64 | } 65 | } 66 | }() 67 | 68 | return client, nil 69 | } 70 | 71 | func etcdConfig() (etcd.Config, error) { 72 | https := false 73 | certificates := []tls.Certificate{} 74 | if *etcdAuthCert != "" { 75 | if *etcdAuthKey == "" { 76 | return etcd.Config{}, errors.New("-etcd.auth.cert requires -etcd.auth.key") 77 | } 78 | https = true 79 | 80 | cert, err := tls.LoadX509KeyPair(*etcdAuthCert, *etcdAuthKey) 81 | if err != nil { 82 | return etcd.Config{}, errors.Wrap(err, "could not load etcd client key pair") 83 | } 84 | 85 | certificates = append(certificates, cert) 86 | } 87 | 88 | caCertPool := x509.NewCertPool() 89 | if *etcdAuthCA != "" { 90 | https = true 91 | caCert, err := ioutil.ReadFile(*etcdAuthCA) 92 | if err != nil { 93 | return etcd.Config{}, errors.Wrap(err, "could not load etcd CA") 94 | } 95 | 96 | caCertPool.AppendCertsFromPEM(caCert) 97 | } 98 | 99 | endpoints := []string{} 100 | if *etcdDiscoverySRV != "" { 101 | _, addrs, err := net.LookupSRV("", "", *etcdDiscoverySRV) 102 | if err != nil { 103 | return etcd.Config{}, errors.Wrapf(err, "could not resolve discovery SRV %v", etcdDiscoverySRV) 104 | } 105 | for _, addr := range addrs { 106 | endpoints = append(endpoints, fmt.Sprintf("%v:%v", addr.Target, addr.Port)) 107 | } 108 | } else if *etcdDiscoveryEndpoints != "" { 109 | endpoints = strings.Split(*etcdDiscoveryEndpoints, ",") 110 | } else { 111 | return etcd.Config{}, errors.New("No etcd discovery mechanism specified (-etcd.discovery.srv, -etcd.discovery.endpoints)") 112 | } 113 | 114 | for _, e := range endpoints { 115 | u, err := url.Parse(e) 116 | if err != nil { 117 | return etcd.Config{}, errors.Wrapf(err, "could not parse initial node %v", e) 118 | } 119 | if https && u.Scheme != "https" { 120 | return etcd.Config{}, errors.Errorf("HTTPS configured, but non https address found in initial nodes: %v", e) 121 | } 122 | } 123 | 124 | var tlsConfig *tls.Config 125 | if https { 126 | tlsConfig = &tls.Config{ 127 | Certificates: certificates, 128 | RootCAs: caCertPool, 129 | } 130 | } 131 | 132 | return etcd.Config{ 133 | Endpoints: endpoints, 134 | TLS: tlsConfig, 135 | Username: *etcdAuthUsername, 136 | Password: *etcdAuthPassword, 137 | }, nil 138 | } 139 | -------------------------------------------------------------------------------- /main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "context" 5 | "flag" 6 | "net/http" 7 | _ "net/http/pprof" 8 | "time" 9 | 10 | "golang.org/x/sync/errgroup" 11 | 12 | "github.com/golang/glog" 13 | dhcp "github.com/krolaw/dhcp4" 14 | "github.com/pkg/errors" 15 | "github.com/prometheus/client_golang/prometheus/promhttp" 16 | ) 17 | 18 | var ( 19 | adminAddr = flag.String("admin-addr", ":9842", "address to serve admin interface on") 20 | serverIP = flag.String("dhcp.server-ip", "10.0.0.1", "dhcp server ip") 21 | serverIF = flag.String("dhcp.server-if", "eth0", "interface to serve on") 22 | subnetMask = flag.String("dhcp.subnet-mask", "255.255.240.0", "the subnet to serve") 23 | router = flag.String("dhcp.router", "10.0.0.1", "gateway to point clients to") 24 | dns = flag.String("dhcp.dns", "10.0.0.1", "dns server to point clients to") 25 | issueFrom = flag.String("dhcp.issue-from", "10.0.0.10", "first ip address to issue to clients") 26 | issueTo = flag.String("dhcp.issue-to", "10.0.0.100", "last ip address to issue to clients") 27 | leaseDuration = flag.Duration("dhcp.lease", time.Hour, "dhcp lease duration") 28 | requestTimeout = flag.Duration("dhcp.request-timeout", 200*time.Millisecond*200, "dhcp request processing timeout") 29 | ) 30 | 31 | func main() { 32 | ctx, cancel := context.WithCancel(context.Background()) 33 | defer cancel() 34 | 35 | flag.Set("logtostderr", "true") 36 | flag.Parse() 37 | 38 | etcd, err := NewETCDStore(ctx) 39 | if err != nil { 40 | glog.Exitf("could not connect to etcd: %v", err) 41 | } 42 | handler := &DHCPHandler{ 43 | client: etcd, 44 | prefix: *etcdPrefix, 45 | timeout: *requestTimeout, 46 | leaseDuration: *leaseDuration, 47 | start: parseIP4(*issueFrom), 48 | end: parseIP4(*issueTo), 49 | ip: parseIP4(*serverIP), 50 | options: dhcp.Options{ 51 | dhcp.OptionSubnetMask: parseIP4(*subnetMask), 52 | dhcp.OptionRouter: parseIP4(*router), 53 | dhcp.OptionDomainNameServer: parseIP4(*dns), 54 | }, 55 | } 56 | 57 | err = handler.bootstrapLeasableRange(ctx) 58 | if err != nil { 59 | glog.Exitf("failed to initialise etcd with leasable range: %v", err) 60 | } 61 | 62 | grp, ctx := errgroup.WithContext(ctx) 63 | 64 | grp.Go(func() error { 65 | http.Handle("/metrics", promhttp.Handler()) 66 | glog.Infof("starting admin server on %v", *adminAddr) 67 | err := listenAndServe(ctx, *adminAddr, http.DefaultServeMux) 68 | return errors.Wrap(err, "could not serve admin server") 69 | }) 70 | 71 | grp.Go(func() error { 72 | glog.Infof("starting dhcp listener") 73 | err := dhcp.ListenAndServeIf(*serverIF, handler) 74 | return errors.Wrap(err, "could not listen to dhcp") 75 | }) 76 | 77 | grp.Go(func() error { 78 | glog.Infof("starting lease monitor") 79 | err := handler.monitorLeases(ctx) 80 | return errors.Wrap(err, "could not monitor leases") 81 | }) 82 | 83 | err = grp.Wait() 84 | if err != nil && errors.Cause(err) != context.Canceled { 85 | glog.Exitf("%v", err.Error()) 86 | } 87 | } 88 | 89 | func listenAndServe(ctx context.Context, addr string, handler http.Handler) error { 90 | srv := &http.Server{ 91 | Addr: addr, 92 | ReadTimeout: 5 * time.Second, 93 | WriteTimeout: 10 * time.Second, 94 | IdleTimeout: 120 * time.Second, 95 | Handler: handler, 96 | } 97 | 98 | go func() { 99 | <-ctx.Done() 100 | srv.Shutdown(ctx) 101 | }() 102 | err := srv.ListenAndServe() 103 | if ctx.Err() == nil { 104 | return err 105 | } 106 | return nil 107 | } 108 | -------------------------------------------------------------------------------- /storage.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "context" 5 | "flag" 6 | "net" 7 | "strings" 8 | "time" 9 | 10 | etcd "github.com/coreos/etcd/clientv3" 11 | etcdutil "github.com/coreos/etcd/clientv3/clientv3util" 12 | etcdpb "github.com/coreos/etcd/etcdserver/etcdserverpb" 13 | "github.com/golang/glog" 14 | dhcp "github.com/krolaw/dhcp4" 15 | "github.com/pkg/errors" 16 | ) 17 | 18 | var ( 19 | monitorInterval = flag.Duration("dhcp.monitor-interval", time.Minute*5, "period to resurrect ips from expired leases at") 20 | ) 21 | 22 | func (h *DHCPHandler) bootstrapLeasableRange(ctx context.Context) error { 23 | kvc := etcd.NewKV(h.client) 24 | for ip := h.start; !ip.Equal(h.end); ip = dhcp.IPAdd(ip, 1) { 25 | freeIPKey := h.prefix + "ips::free::" + ip.String() 26 | leasedIPKey := h.prefix + "ips::leased::" + ip.String() 27 | res, err := kvc.Txn(ctx).If( 28 | etcdutil.KeyMissing(freeIPKey), 29 | etcdutil.KeyMissing(leasedIPKey), 30 | ).Then( 31 | etcd.OpPut(freeIPKey, ip.String()), 32 | ).Commit() 33 | if err != nil { 34 | return errors.Wrap(err, "could not move ip to free state") 35 | } 36 | if res.Succeeded { 37 | glog.Infof("established %v as free", ip) 38 | } 39 | } 40 | return nil 41 | } 42 | 43 | func (h *DHCPHandler) monitorLeases(ctx context.Context) error { 44 | t := time.NewTicker(*monitorInterval) 45 | defer t.Stop() 46 | for { 47 | err := h.resurrectLeases(ctx) 48 | if err != nil { 49 | glog.Errorf("could not resurrect leases: %v", err) 50 | } 51 | 52 | select { 53 | case <-ctx.Done(): 54 | return ctx.Err() 55 | case <-t.C: 56 | } 57 | } 58 | } 59 | 60 | func (h *DHCPHandler) resurrectLeases(ctx context.Context) error { 61 | kvc := etcd.NewKV(h.client) 62 | leasedIPPrefix := h.prefix + "ips::leased::" 63 | glog.V(2).Infof("listing ips under %v", leasedIPPrefix) 64 | resp, err := kvc.Get(ctx, leasedIPPrefix, etcd.WithPrefix()) 65 | if err != nil { 66 | return errors.Wrap(err, "could not list leased ips") 67 | } 68 | 69 | leased := map[string]struct{}{} 70 | for _, kv := range resp.Kvs { 71 | parts := strings.Split(string(kv.Key), "::") 72 | ip := parts[len(parts)-1] 73 | 74 | leased[ip] = struct{}{} 75 | } 76 | 77 | freeIPPrefix := h.prefix + "ips::free::" 78 | glog.V(2).Infof("listing ips under %v", freeIPPrefix) 79 | resp, err = kvc.Get(ctx, freeIPPrefix, etcd.WithPrefix()) 80 | if err != nil { 81 | return errors.Wrap(err, "could not list free ips") 82 | } 83 | 84 | free := map[string]struct{}{} 85 | for _, kv := range resp.Kvs { 86 | parts := strings.Split(string(kv.Key), "::") 87 | ip := parts[len(parts)-1] 88 | 89 | free[ip] = struct{}{} 90 | } 91 | 92 | for ip := h.start; !ip.Equal(h.end); ip = dhcp.IPAdd(ip, 1) { 93 | if _, ok := free[ip.String()]; ok { 94 | continue 95 | } 96 | if _, ok := leased[ip.String()]; ok { 97 | continue 98 | } 99 | 100 | glog.V(2).Infof("moving %v from leased to free", ip) 101 | freeIPKey := h.prefix + "ips::free::" + ip.String() 102 | leasedIPKey := h.prefix + "ips::leased::" + ip.String() 103 | 104 | res, err := kvc.Txn(ctx).If( 105 | etcdutil.KeyMissing(freeIPKey), 106 | etcdutil.KeyMissing(leasedIPKey), 107 | ).Then( 108 | etcd.OpPut(freeIPKey, ip.String()), 109 | ).Commit() 110 | if err != nil { 111 | return errors.Wrap(err, "could not move ip to free state") 112 | } 113 | if res.Succeeded { 114 | glog.Infof("resurrected %v", ip) 115 | } 116 | } 117 | return nil 118 | } 119 | 120 | func (h *DHCPHandler) nicLeasedIP(ctx context.Context, nic string) (net.IP, error) { 121 | kvc := etcd.NewKV(h.client) 122 | key := h.prefix + "nics::leased::" + nic 123 | glog.V(2).Infof("GET %v", key) 124 | resp, err := kvc.Get(ctx, key) 125 | if err != nil { 126 | return nil, errors.Wrap(err, "could not get etcd key") 127 | } 128 | if len(resp.Kvs) == 0 { 129 | return nil, nil 130 | } 131 | return parseIP4(string(resp.Kvs[0].Value)), nil 132 | } 133 | 134 | func (h *DHCPHandler) freeIP(ctx context.Context) (net.IP, error) { 135 | kvc := etcd.NewKV(h.client) 136 | prefix := h.prefix + "ips::free::" 137 | glog.V(2).Infof("GET PREFIX(%v)", prefix) 138 | resp, err := kvc.Get(ctx, prefix, etcd.WithPrefix(), etcd.WithSort(etcd.SortByKey, etcd.SortAscend)) 139 | if err != nil { 140 | return nil, errors.Wrap(err, "could not get etcd key") 141 | } 142 | if len(resp.Kvs) == 0 { 143 | return nil, errors.New("no free IP addresses") 144 | } 145 | ip := string(resp.Kvs[0].Value) 146 | return parseIP4(ip), nil 147 | } 148 | 149 | func (h *DHCPHandler) leaseIP(ctx context.Context, ip net.IP, nic string, ttl time.Duration) error { 150 | lease, err := etcd.NewLease(h.client).Grant(ctx, int64(ttl.Seconds())) 151 | if err != nil { 152 | return errors.Wrap(err, "could not create new lease") 153 | } 154 | 155 | freeIPKey := h.prefix + "ips::free::" + ip.String() 156 | leasedIPKey := h.prefix + "ips::leased::" + ip.String() 157 | leasedNicKey := h.prefix + "nics::leased::" + nic 158 | 159 | res, err := etcd.NewKV(h.client).Txn(ctx).If( 160 | // if the ip was previously free 161 | etcdutil.KeyExists(freeIPKey), 162 | ).Then( 163 | etcd.OpTxn([]etcd.Cmp{ 164 | etcdutil.KeyMissing(leasedIPKey), 165 | etcdutil.KeyMissing(leasedNicKey), 166 | }, []etcd.Op{ 167 | // Unfree it, and associate it with this nic 168 | etcd.OpDelete(freeIPKey), 169 | etcd.OpPut(leasedIPKey, nic, etcd.WithLease(lease.ID)), 170 | etcd.OpPut(leasedNicKey, ip.String(), etcd.WithLease(lease.ID)), 171 | }, nil), 172 | ).Else( 173 | // Otherwise, we're _probably_ renewing it, so check that it's currently 174 | // associated with us 175 | etcd.OpTxn([]etcd.Cmp{ 176 | etcd.Compare(etcd.Value(leasedIPKey), "=", nic), 177 | etcd.Compare(etcd.Value(leasedNicKey), "=", ip.String()), 178 | }, []etcd.Op{ 179 | // And if it is, renew the lease 180 | etcd.OpPut(leasedIPKey, nic, etcd.WithLease(lease.ID)), 181 | etcd.OpPut(leasedNicKey, ip.String(), etcd.WithLease(lease.ID)), 182 | }, nil), 183 | ).Commit() 184 | if err != nil { 185 | return errors.Wrap(err, "could not update for leased ip") 186 | } 187 | 188 | // If we did an else in the nested transaction, we failed to actually update 189 | // the lease 190 | if !res.Responses[0].Response.(*etcdpb.ResponseOp_ResponseTxn).ResponseTxn.Succeeded { 191 | return errors.New("ip is no longer free") 192 | } 193 | 194 | return nil 195 | } 196 | 197 | func (h *DHCPHandler) revokeLease(ctx context.Context, nic string) error { 198 | kvc := etcd.NewKV(h.client) 199 | leasedNicKey := h.prefix + "nics::leased::" + nic 200 | res, err := kvc.Get(ctx, leasedNicKey) 201 | if err != nil { 202 | return errors.Wrap(err, "could not get nic's current lease") 203 | } 204 | ip := string(res.Kvs[0].Value) 205 | leasedIPKey := h.prefix + "ips::leased::" + ip 206 | freeIPKey := h.prefix + "ips::free::" + ip 207 | 208 | _, err = kvc.Txn(ctx).If( 209 | etcdutil.KeyExists(leasedIPKey), 210 | etcdutil.KeyExists(leasedNicKey), 211 | ).Then( 212 | etcd.OpDelete(leasedIPKey), 213 | etcd.OpDelete(leasedNicKey), 214 | etcd.OpPut(freeIPKey, ip), 215 | ).Commit() 216 | return errors.Wrap(err, "could not delete lease") 217 | } 218 | 219 | func parseIP4(raw string) net.IP { 220 | ip := net.ParseIP(raw) 221 | if ip == nil { 222 | return nil 223 | } 224 | return ip[12:16] 225 | } 226 | --------------------------------------------------------------------------------