Pull request: 2606 substitute nclient4 with fork
Merge in DNS/adguard-home from 2606-rm-nclient4 to master
Closes #2606.
Squashed commit of the following:
commit a9abc3ac27b19ef0ab6c4dea8610d97034b24ec2
Author: Eugene Burkov <e.burkov@adguard.com>
Date: Wed Apr 21 13:22:56 2021 +0300
nclient4: rm
commit abcd0042a7f0d1fbf7ebb398a06414bbc7fc2528
Author: Eugene Burkov <e.burkov@adguard.com>
Date: Wed Apr 21 13:19:11 2021 +0300
all: clear changes
commit d1bc3b83f00be07bf9bb97cfe6ef773e07ae8710
Merge: 1b1ab0b9 c2667558
Author: Eugene Burkov <e.burkov@adguard.com>
Date: Wed Apr 21 12:58:48 2021 +0300
Merge branch 'master' into 2606-rm-nclient4
commit 1b1ab0b9796552854ecffefe8e79ca24b472fed0
Author: Eugene Burkov <e.burkov@adguard.com>
Date: Mon Apr 19 18:53:04 2021 +0300
dhcpd: subst nclient4 with fork
This commit is contained in:
Eugene Burkov
parent
c26675585d
commit
2e4e1973d9
6
go.mod
6
go.mod
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@ -16,14 +16,11 @@ require (
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github.com/gobuffalo/packr/v2 v2.8.1 // indirect
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github.com/google/go-cmp v0.5.5 // indirect
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github.com/google/renameio v1.0.1-0.20210406141108-81588dbe0453
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github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714
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github.com/insomniacslk/dhcp v0.0.0-20210310193751-cfd4d47082c2
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github.com/kardianos/service v1.2.0
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github.com/karrick/godirwalk v1.16.1 // indirect
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github.com/lucas-clemente/quic-go v0.20.1
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github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7
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github.com/mdlayher/netlink v1.4.0
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github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065
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github.com/miekg/dns v1.1.40
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github.com/rogpeppe/go-internal v1.7.0 // indirect
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github.com/satori/go.uuid v1.2.0
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@ -31,7 +28,6 @@ require (
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github.com/spf13/cobra v1.1.3 // indirect
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github.com/stretchr/testify v1.7.0
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github.com/ti-mo/netfilter v0.4.0
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github.com/u-root/u-root v7.0.0+incompatible
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go.etcd.io/bbolt v1.3.5
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golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83
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golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4
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@ -43,3 +39,5 @@ require (
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gopkg.in/yaml.v2 v2.4.0
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howett.net/plist v0.0.0-20201203080718-1454fab16a06
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)
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replace github.com/insomniacslk/dhcp => github.com/AdguardTeam/dhcp v0.0.0-20210420175708-50b0efd52063
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12
go.sum
12
go.sum
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@ -18,11 +18,12 @@ dmitri.shuralyov.com/html/belt v0.0.0-20180602232347-f7d459c86be0/go.mod h1:JLBr
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dmitri.shuralyov.com/service/change v0.0.0-20181023043359-a85b471d5412/go.mod h1:a1inKt/atXimZ4Mv927x+r7UpyzRUf4emIoiiSC2TN4=
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dmitri.shuralyov.com/state v0.0.0-20180228185332-28bcc343414c/go.mod h1:0PRwlb0D6DFvNNtx+9ybjezNCa8XF0xaYcETyp6rHWU=
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git.apache.org/thrift.git v0.0.0-20180902110319-2566ecd5d999/go.mod h1:fPE2ZNJGynbRyZ4dJvy6G277gSllfV2HJqblrnkyeyg=
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github.com/AdguardTeam/dhcp v0.0.0-20210420175708-50b0efd52063 h1:RBsQppxEJEqHApY6WDBkM2H0UG5wt57RcT0El2WGdp8=
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github.com/AdguardTeam/dhcp v0.0.0-20210420175708-50b0efd52063/go.mod h1:TKl4jN3Voofo4UJIicyNhWGp/nlQqQkFxmwIFTvBkKI=
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github.com/AdguardTeam/dnsproxy v0.37.1 h1:vULyF1+xSI7vV99m8GD2hmOuCQrpu87awyeSe5qtFbA=
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github.com/AdguardTeam/dnsproxy v0.37.1/go.mod h1:xkJWEuTr550gPDmB9azsciKZzSXjf9wMn+Ji54PQ4gE=
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github.com/AdguardTeam/golibs v0.4.0/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKUzB6TIgtUj4=
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github.com/AdguardTeam/golibs v0.4.2/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKUzB6TIgtUj4=
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github.com/AdguardTeam/golibs v0.4.4 h1:cM9UySQiYFW79zo5XRwnaIWVzfW4eNXmZktMrWbthpw=
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github.com/AdguardTeam/golibs v0.4.4/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKUzB6TIgtUj4=
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github.com/AdguardTeam/golibs v0.4.5 h1:RRA9ZsmbJEN4OllAx0BcfvSbRBxxpWluJijBYmtp13U=
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github.com/AdguardTeam/golibs v0.4.5/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKUzB6TIgtUj4=
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@ -68,7 +69,6 @@ github.com/cheekybits/genny v1.0.0/go.mod h1:+tQajlRqAUrPI7DOSpB0XAqZYtQakVtB7wX
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github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
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github.com/coreos/bbolt v1.3.2/go.mod h1:iRUV2dpdMOn7Bo10OQBFzIJO9kkE559Wcmn+qkEiiKk=
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github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
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github.com/coreos/etcd v3.3.13+incompatible h1:8F3hqu9fGYLBifCmRCJsicFqDx/D68Rt3q1JMazcgBQ=
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github.com/coreos/etcd v3.3.13+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
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github.com/coreos/go-etcd v2.0.0+incompatible/go.mod h1:Jez6KQU2B/sWsbdaef3ED8NzMklzPG4d5KIOhIy30Tk=
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github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
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@ -125,7 +125,6 @@ github.com/gobuffalo/packr/v2 v2.5.1/go.mod h1:8f9c96ITobJlPzI44jj+4tHnEKNt0xXWS
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github.com/gobuffalo/packr/v2 v2.8.1 h1:tkQpju6i3EtMXJ9uoF5GT6kB+LMTimDWD8Xvbz6zDVA=
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github.com/gobuffalo/packr/v2 v2.8.1/go.mod h1:c/PLlOuTU+p3SybaJATW3H6lX/iK7xEz5OeMf+NnJpg=
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github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
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github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
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github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
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github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
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github.com/golang/groupcache v0.0.0-20190129154638-5b532d6fd5ef/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
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@ -133,7 +132,6 @@ github.com/golang/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:tluoj9z5200j
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github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
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github.com/golang/mock v1.2.0/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
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github.com/golang/mock v1.3.1/go.mod h1:sBzyDLLjw3U8JLTeZvSv8jJB+tU5PVekmnlKIyFUx0Y=
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github.com/golang/mock v1.4.4 h1:l75CXGRSwbaYNpl/Z2X1XIIAMSCquvXgpVZDhwEIJsc=
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github.com/golang/mock v1.4.4/go.mod h1:l3mdAwkq5BuhzHwde/uurv3sEJeZMXNpwsxVWU71h+4=
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github.com/golang/mock v1.5.0 h1:jlYHihg//f7RRwuPfptm04yp4s7O6Kw8EZiVYIGcH0g=
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github.com/golang/mock v1.5.0/go.mod h1:CWnOUgYIOo4TcNZ0wHX3YZCqsaM1I1Jvs6v3mP3KVu8=
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@ -205,11 +203,7 @@ github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714 h1:/jC7qQFrv8
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github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Goc3h8EklBH5mspfHFxBnEoURQCGzQQH1ga9Myjvis=
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github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
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github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
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github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
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github.com/insomniacslk/dhcp v0.0.0-20210310193751-cfd4d47082c2 h1:NpTIlXznCStsY88jU+Gh1Dy5dt/jYV4z4uU8h2TUOt4=
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github.com/insomniacslk/dhcp v0.0.0-20210310193751-cfd4d47082c2/go.mod h1:TKl4jN3Voofo4UJIicyNhWGp/nlQqQkFxmwIFTvBkKI=
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github.com/jellevandenhooff/dkim v0.0.0-20150330215556-f50fe3d243e1/go.mod h1:E0B/fFc00Y+Rasa88328GlI/XbtyysCtTHZS8h7IrBU=
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github.com/jessevdk/go-flags v1.4.0 h1:4IU2WS7AumrZ/40jfhf4QVDMsQwqA7VEHozFRrGARJA=
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github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
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github.com/joho/godotenv v1.3.0 h1:Zjp+RcGpHhGlrMbJzXTrZZPrWj+1vfm90La1wgB6Bhc=
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github.com/joho/godotenv v1.3.0/go.mod h1:7hK45KPybAkOC6peb+G5yklZfMxEjkZhHbwpqxOKXbg=
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@ -655,7 +649,6 @@ google.golang.org/genproto v0.0.0-20190801165951-fa694d86fc64/go.mod h1:DMBHOl98
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google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
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google.golang.org/genproto v0.0.0-20190911173649-1774047e7e51/go.mod h1:IbNlFCBrqXvoKpeg0TB2l7cyZUmoaFKYIwrEpbDKLA8=
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google.golang.org/genproto v0.0.0-20191108220845-16a3f7862a1a/go.mod h1:n3cpQtvxv34hfy77yVDNjmbRyujviMdxYliBSkLhpCc=
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google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013 h1:+kGHl1aib/qcwaRi1CbqBZ1rk19r85MNUf8HaBghugY=
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google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
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google.golang.org/grpc v1.14.0/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
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google.golang.org/grpc v1.16.0/go.mod h1:0JHn/cJsOMiMfNA9+DeHDlAU7KAAB5GDlYFpa9MZMio=
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@ -665,7 +658,6 @@ google.golang.org/grpc v1.20.1/go.mod h1:10oTOabMzJvdu6/UiuZezV6QK5dSlG84ov/aaiq
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google.golang.org/grpc v1.21.0/go.mod h1:oYelfM1adQP15Ek0mdvEgi9Df8B9CZIaU1084ijfRaM=
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google.golang.org/grpc v1.21.1/go.mod h1:oYelfM1adQP15Ek0mdvEgi9Df8B9CZIaU1084ijfRaM=
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google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
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google.golang.org/grpc v1.27.0 h1:rRYRFMVgRv6E0D70Skyfsr28tDXIuuPZyWGMPdMcnXg=
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google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk=
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google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
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google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
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@ -10,9 +10,9 @@ import (
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"runtime"
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"time"
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"github.com/AdguardTeam/AdGuardHome/internal/dhcpd/nclient4"
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"github.com/AdguardTeam/golibs/log"
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"github.com/insomniacslk/dhcp/dhcpv4"
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"github.com/insomniacslk/dhcp/dhcpv4/nclient4"
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"github.com/insomniacslk/dhcp/dhcpv6"
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"github.com/insomniacslk/dhcp/dhcpv6/nclient6"
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"github.com/insomniacslk/dhcp/iana"
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@ -1,554 +0,0 @@
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// Copyright 2018 the u-root Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux netbsd openbsd solaris
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// +build go1.12
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// Package nclient4 is a small, minimum-functionality client for DHCPv4.
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//
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// It only supports the 4-way DHCPv4 Discover-Offer-Request-Ack handshake as
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// well as the Request-Ack renewal process.
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// Originally from here: github.com/insomniacslk/dhcp/dhcpv4/nclient4
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// with the difference that this package can be built on UNIX (not just Linux),
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// because github.com/mdlayher/raw package supports it.
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package nclient4
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import (
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"bytes"
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"context"
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"errors"
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"fmt"
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"net"
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"sync"
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"sync/atomic"
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"time"
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"github.com/insomniacslk/dhcp/dhcpv4"
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)
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const (
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defaultBufferCap = 5
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// DefaultTimeout is the default value for read-timeout if option WithTimeout is not set
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DefaultTimeout = 5 * time.Second
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// DefaultRetries is amount of retries will be done if no answer was received within read-timeout amount of time
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DefaultRetries = 3
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// MaxMessageSize is the value to be used for DHCP option "MaxMessageSize".
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MaxMessageSize = 1500
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// ClientPort is the port that DHCP clients listen on.
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ClientPort = 68
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// ServerPort is the port that DHCP servers and relay agents listen on.
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ServerPort = 67
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)
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// DefaultServers is the address of all link-local DHCP servers and
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// relay agents.
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var DefaultServers = &net.UDPAddr{
|
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IP: net.IPv4bcast,
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Port: ServerPort,
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}
|
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||||
var (
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// ErrNoResponse is returned when no response packet is received.
|
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ErrNoResponse = errors.New("no matching response packet received")
|
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// ErrNoConn is returned when NewWithConn is called with nil-value as conn.
|
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ErrNoConn = errors.New("conn is nil")
|
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|
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// ErrNoIfaceHWAddr is returned when NewWithConn is called with nil-value as ifaceHWAddr
|
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ErrNoIfaceHWAddr = errors.New("ifaceHWAddr is nil")
|
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)
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// pendingCh is a channel associated with a pending TransactionID.
|
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type pendingCh struct {
|
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// SendAndRead closes done to indicate that it wishes for no more
|
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// messages for this particular XID.
|
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done <-chan struct{}
|
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|
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// ch is used by the receive loop to distribute DHCP messages.
|
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ch chan<- *dhcpv4.DHCPv4
|
||||
}
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|
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// Logger is a handler which will be used to output logging messages
|
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type Logger interface {
|
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// PrintMessage print _all_ DHCP messages
|
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PrintMessage(prefix string, message *dhcpv4.DHCPv4)
|
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|
||||
// Printf is use to print the rest debugging information
|
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Printf(format string, v ...interface{})
|
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}
|
||||
|
||||
// EmptyLogger prints nothing
|
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type EmptyLogger struct{}
|
||||
|
||||
// Printf is just a dummy function that does nothing
|
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func (e EmptyLogger) Printf(format string, v ...interface{}) {}
|
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|
||||
// PrintMessage is just a dummy function that does nothing
|
||||
func (e EmptyLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4) {}
|
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|
||||
// Printfer is used for actual output of the logger. For example *log.Logger is a Printfer.
|
||||
type Printfer interface {
|
||||
// Printf is the function for logging output. Arguments are handled in the manner of fmt.Printf.
|
||||
Printf(format string, v ...interface{})
|
||||
}
|
||||
|
||||
// ShortSummaryLogger is a wrapper for Printfer to implement interface Logger.
|
||||
// DHCP messages are printed in the short format.
|
||||
type ShortSummaryLogger struct {
|
||||
// Printfer is used for actual output of the logger
|
||||
Printfer
|
||||
}
|
||||
|
||||
// Printf prints a log message as-is via predefined Printfer
|
||||
func (s ShortSummaryLogger) Printf(format string, v ...interface{}) {
|
||||
s.Printfer.Printf(format, v...)
|
||||
}
|
||||
|
||||
// PrintMessage prints a DHCP message in the short format via predefined Printfer
|
||||
func (s ShortSummaryLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4) {
|
||||
s.Printf("%s: %s", prefix, message)
|
||||
}
|
||||
|
||||
// DebugLogger is a wrapper for Printfer to implement interface Logger.
|
||||
// DHCP messages are printed in the long format.
|
||||
type DebugLogger struct {
|
||||
// Printfer is used for actual output of the logger
|
||||
Printfer
|
||||
}
|
||||
|
||||
// Printf prints a log message as-is via predefined Printfer
|
||||
func (d DebugLogger) Printf(format string, v ...interface{}) {
|
||||
d.Printfer.Printf(format, v...)
|
||||
}
|
||||
|
||||
// PrintMessage prints a DHCP message in the long format via predefined Printfer
|
||||
func (d DebugLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4) {
|
||||
d.Printf("%s: %s", prefix, message.Summary())
|
||||
}
|
||||
|
||||
// Client is an IPv4 DHCP client.
|
||||
type Client struct {
|
||||
ifaceHWAddr net.HardwareAddr
|
||||
conn net.PacketConn
|
||||
timeout time.Duration
|
||||
retry int
|
||||
logger Logger
|
||||
|
||||
// bufferCap is the channel capacity for each TransactionID.
|
||||
bufferCap int
|
||||
|
||||
// serverAddr is the UDP address to send all packets to.
|
||||
//
|
||||
// This may be an actual broadcast address, or a unicast address.
|
||||
serverAddr *net.UDPAddr
|
||||
|
||||
// closed is an atomic bool set to 1 when done is closed.
|
||||
closed uint32
|
||||
|
||||
// done is closed to unblock the receive loop.
|
||||
done chan struct{}
|
||||
|
||||
// wg protects any spawned goroutines, namely the receiveLoop.
|
||||
wg sync.WaitGroup
|
||||
|
||||
pendingMu sync.Mutex
|
||||
// pending stores the distribution channels for each pending
|
||||
// TransactionID. receiveLoop uses this map to determine which channel
|
||||
// to send a new DHCP message to.
|
||||
pending map[dhcpv4.TransactionID]*pendingCh
|
||||
}
|
||||
|
||||
// New returns a client usable with an unconfigured interface.
|
||||
func New(iface string, opts ...ClientOpt) (*Client, error) {
|
||||
return new(iface, nil, nil, opts...)
|
||||
}
|
||||
|
||||
// NewWithConn creates a new DHCP client that sends and receives packets on the
|
||||
// given interface.
|
||||
func NewWithConn(conn net.PacketConn, ifaceHWAddr net.HardwareAddr, opts ...ClientOpt) (*Client, error) {
|
||||
return new(``, conn, ifaceHWAddr, opts...)
|
||||
}
|
||||
|
||||
func new(iface string, conn net.PacketConn, ifaceHWAddr net.HardwareAddr, opts ...ClientOpt) (*Client, error) {
|
||||
c := &Client{
|
||||
ifaceHWAddr: ifaceHWAddr,
|
||||
timeout: DefaultTimeout,
|
||||
retry: DefaultRetries,
|
||||
serverAddr: DefaultServers,
|
||||
bufferCap: defaultBufferCap,
|
||||
conn: conn,
|
||||
logger: EmptyLogger{},
|
||||
|
||||
done: make(chan struct{}),
|
||||
pending: make(map[dhcpv4.TransactionID]*pendingCh),
|
||||
}
|
||||
|
||||
for _, opt := range opts {
|
||||
err := opt(c)
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("unable to apply option: %w", err)
|
||||
}
|
||||
}
|
||||
|
||||
if c.ifaceHWAddr == nil {
|
||||
if iface == `` {
|
||||
return nil, ErrNoIfaceHWAddr
|
||||
}
|
||||
|
||||
i, err := net.InterfaceByName(iface)
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("unable to get interface information: %w", err)
|
||||
}
|
||||
|
||||
c.ifaceHWAddr = i.HardwareAddr
|
||||
}
|
||||
|
||||
if c.conn == nil {
|
||||
var err error
|
||||
if iface == `` {
|
||||
return nil, ErrNoConn
|
||||
}
|
||||
c.conn, err = NewRawUDPConn(iface, ClientPort) // broadcast
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("unable to open a broadcasting socket: %w", err)
|
||||
}
|
||||
}
|
||||
c.wg.Add(1)
|
||||
go c.receiveLoop()
|
||||
return c, nil
|
||||
}
|
||||
|
||||
// Close closes the underlying connection.
|
||||
func (c *Client) Close() error {
|
||||
// Make sure not to close done twice.
|
||||
if !atomic.CompareAndSwapUint32(&c.closed, 0, 1) {
|
||||
return nil
|
||||
}
|
||||
|
||||
err := c.conn.Close()
|
||||
|
||||
// Closing c.done sets off a chain reaction:
|
||||
//
|
||||
// Any SendAndRead unblocks trying to receive more messages, which
|
||||
// means rem() gets called.
|
||||
//
|
||||
// rem() should be unblocking receiveLoop if it is blocked.
|
||||
//
|
||||
// receiveLoop should then exit gracefully.
|
||||
close(c.done)
|
||||
|
||||
// Wait for receiveLoop to stop.
|
||||
c.wg.Wait()
|
||||
|
||||
return err
|
||||
}
|
||||
|
||||
func (c *Client) isClosed() bool {
|
||||
return atomic.LoadUint32(&c.closed) != 0
|
||||
}
|
||||
|
||||
func (c *Client) receiveLoop() {
|
||||
defer c.wg.Done()
|
||||
for {
|
||||
// TODO: Clients can send a "max packet size" option in their
|
||||
// packets, IIRC. Choose a reasonable size and set it.
|
||||
b := make([]byte, MaxMessageSize)
|
||||
n, _, err := c.conn.ReadFrom(b)
|
||||
if err != nil {
|
||||
if !c.isClosed() {
|
||||
c.logger.Printf("error reading from UDP connection: %v", err)
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
msg, err := dhcpv4.FromBytes(b[:n])
|
||||
if err != nil {
|
||||
// Not a valid DHCP packet; keep listening.
|
||||
continue
|
||||
}
|
||||
|
||||
if msg.OpCode != dhcpv4.OpcodeBootReply {
|
||||
// Not a response message.
|
||||
continue
|
||||
}
|
||||
|
||||
// This is a somewhat non-standard check, by the looks
|
||||
// of RFC 2131. It should work as long as the DHCP
|
||||
// server is spec-compliant for the HWAddr field.
|
||||
if c.ifaceHWAddr != nil && !bytes.Equal(c.ifaceHWAddr, msg.ClientHWAddr) {
|
||||
// Not for us.
|
||||
continue
|
||||
}
|
||||
|
||||
c.pendingMu.Lock()
|
||||
p, ok := c.pending[msg.TransactionID]
|
||||
if ok {
|
||||
select {
|
||||
case <-p.done:
|
||||
close(p.ch)
|
||||
delete(c.pending, msg.TransactionID)
|
||||
|
||||
// This send may block.
|
||||
case p.ch <- msg:
|
||||
}
|
||||
}
|
||||
c.pendingMu.Unlock()
|
||||
}
|
||||
}
|
||||
|
||||
// ClientOpt is a function that configures the Client.
|
||||
type ClientOpt func(c *Client) error
|
||||
|
||||
// WithTimeout configures the retransmission timeout.
|
||||
//
|
||||
// Default is 5 seconds.
|
||||
func WithTimeout(d time.Duration) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
c.timeout = d
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// WithLogger set the logger (see interface Logger).
|
||||
func WithLogger(newLogger Logger) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
c.logger = newLogger
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// WithUnicast forces client to send messages as unicast frames.
|
||||
// By default client sends messages as broadcast frames even if server address is defined.
|
||||
//
|
||||
// srcAddr is both:
|
||||
// * The source address of outgoing frames.
|
||||
// * The address to be listened for incoming frames.
|
||||
func WithUnicast(srcAddr *net.UDPAddr) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
if srcAddr == nil {
|
||||
srcAddr = &net.UDPAddr{Port: ServerPort}
|
||||
}
|
||||
c.conn, err = net.ListenUDP("udp4", srcAddr)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("unable to start listening UDP port: %w", err)
|
||||
}
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// WithHWAddr tells to the Client to receive messages destinated to selected
|
||||
// hardware address
|
||||
func WithHWAddr(hwAddr net.HardwareAddr) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
c.ifaceHWAddr = hwAddr
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// WithRetry configures the number of retransmissions to attempt.
|
||||
//
|
||||
// Default is 3.
|
||||
func WithRetry(r int) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
c.retry = r
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// WithServerAddr configures the address to send messages to.
|
||||
func WithServerAddr(n *net.UDPAddr) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
c.serverAddr = n
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// Matcher matches DHCP packets.
|
||||
type Matcher func(*dhcpv4.DHCPv4) bool
|
||||
|
||||
// IsMessageType returns a matcher that checks for the message type.
|
||||
//
|
||||
// If t is MessageTypeNone, all packets are matched.
|
||||
func IsMessageType(t dhcpv4.MessageType) Matcher {
|
||||
return func(p *dhcpv4.DHCPv4) bool {
|
||||
return p.MessageType() == t || t == dhcpv4.MessageTypeNone
|
||||
}
|
||||
}
|
||||
|
||||
// DiscoverOffer sends a DHCPDiscover message and returns the first valid offer
|
||||
// received.
|
||||
func (c *Client) DiscoverOffer(ctx context.Context, modifiers ...dhcpv4.Modifier) (offer *dhcpv4.DHCPv4, err error) {
|
||||
// RFC 2131, Section 4.4.1, Table 5 details what a DISCOVER packet should
|
||||
// contain.
|
||||
discover, err := dhcpv4.NewDiscovery(c.ifaceHWAddr, dhcpv4.PrependModifiers(modifiers,
|
||||
dhcpv4.WithOption(dhcpv4.OptMaxMessageSize(MaxMessageSize)))...)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("unable to create a discovery request: %w", err)
|
||||
return
|
||||
}
|
||||
|
||||
offer, err = c.SendAndRead(ctx, c.serverAddr, discover, IsMessageType(dhcpv4.MessageTypeOffer))
|
||||
if err != nil {
|
||||
err = fmt.Errorf("got an error while the discovery request: %w", err)
|
||||
return
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// Request completes the 4-way Discover-Offer-Request-Ack handshake.
|
||||
//
|
||||
// Note that modifiers will be applied *both* to Discover and Request packets.
|
||||
func (c *Client) Request(ctx context.Context, modifiers ...dhcpv4.Modifier) (offer, ack *dhcpv4.DHCPv4, err error) {
|
||||
offer, err = c.DiscoverOffer(ctx, modifiers...)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("unable to receive an offer: %w", err)
|
||||
return
|
||||
}
|
||||
|
||||
// TODO(chrisko): should this be unicast to the server?
|
||||
request, err := dhcpv4.NewRequestFromOffer(offer, dhcpv4.PrependModifiers(modifiers,
|
||||
dhcpv4.WithOption(dhcpv4.OptMaxMessageSize(MaxMessageSize)))...)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("unable to create a request: %w", err)
|
||||
return
|
||||
}
|
||||
|
||||
ack, err = c.SendAndRead(ctx, c.serverAddr, request, nil)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("got an error while processing the request: %w", err)
|
||||
return
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// ErrTransactionIDInUse is returned if there were an attempt to send a message
|
||||
// with the same TransactionID as we are already waiting an answer for.
|
||||
type ErrTransactionIDInUse struct {
|
||||
// TransactionID is the transaction ID of the message which the error is related to.
|
||||
TransactionID dhcpv4.TransactionID
|
||||
}
|
||||
|
||||
// Error is just the method to comply interface "error".
|
||||
func (err *ErrTransactionIDInUse) Error() string {
|
||||
return fmt.Sprintf("transaction ID %s already in use", err.TransactionID)
|
||||
}
|
||||
|
||||
// send sends p to destination and returns a response channel.
|
||||
//
|
||||
// Responses will be matched by transaction ID and ClientHWAddr.
|
||||
//
|
||||
// The returned lambda function must be called after all desired responses have
|
||||
// been received in order to return the Transaction ID to the usable pool.
|
||||
func (c *Client) send(dest *net.UDPAddr, msg *dhcpv4.DHCPv4) (resp <-chan *dhcpv4.DHCPv4, cancel func(), err error) {
|
||||
c.pendingMu.Lock()
|
||||
if _, ok := c.pending[msg.TransactionID]; ok {
|
||||
c.pendingMu.Unlock()
|
||||
return nil, nil, &ErrTransactionIDInUse{msg.TransactionID}
|
||||
}
|
||||
|
||||
ch := make(chan *dhcpv4.DHCPv4, c.bufferCap)
|
||||
done := make(chan struct{})
|
||||
c.pending[msg.TransactionID] = &pendingCh{done: done, ch: ch}
|
||||
c.pendingMu.Unlock()
|
||||
|
||||
cancel = func() {
|
||||
// Why can't we just close ch here?
|
||||
//
|
||||
// Because receiveLoop may potentially be blocked trying to
|
||||
// send on ch. We gotta unblock it first, and then we can take
|
||||
// the lock and remove the XID from the pending transaction
|
||||
// map.
|
||||
close(done)
|
||||
|
||||
c.pendingMu.Lock()
|
||||
if p, ok := c.pending[msg.TransactionID]; ok {
|
||||
close(p.ch)
|
||||
delete(c.pending, msg.TransactionID)
|
||||
}
|
||||
c.pendingMu.Unlock()
|
||||
}
|
||||
|
||||
if _, err = c.conn.WriteTo(msg.ToBytes(), dest); err != nil {
|
||||
cancel()
|
||||
return nil, nil, fmt.Errorf("error writing packet to connection: %w", err)
|
||||
}
|
||||
return ch, cancel, nil
|
||||
}
|
||||
|
||||
// This error should never be visible to users.
|
||||
// It is used only to increase the timeout in retryFn.
|
||||
var errDeadlineExceeded = errors.New("INTERNAL ERROR: deadline exceeded")
|
||||
|
||||
// SendAndRead sends a packet p to a destination dest and waits for the first
|
||||
// response matching `match` as well as its Transaction ID and ClientHWAddr.
|
||||
//
|
||||
// If match is nil, the first packet matching the Transaction ID and
|
||||
// ClientHWAddr is returned.
|
||||
func (c *Client) SendAndRead(ctx context.Context, dest *net.UDPAddr, p *dhcpv4.DHCPv4, match Matcher) (*dhcpv4.DHCPv4, error) {
|
||||
var response *dhcpv4.DHCPv4
|
||||
err := c.retryFn(func(timeout time.Duration) error {
|
||||
ch, rem, err := c.send(dest, p)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
c.logger.PrintMessage("sent message", p)
|
||||
defer rem()
|
||||
|
||||
for {
|
||||
select {
|
||||
case <-c.done:
|
||||
return ErrNoResponse
|
||||
|
||||
case <-time.After(timeout):
|
||||
return errDeadlineExceeded
|
||||
|
||||
case <-ctx.Done():
|
||||
return ctx.Err()
|
||||
|
||||
case packet := <-ch:
|
||||
if match == nil || match(packet) {
|
||||
c.logger.PrintMessage("received message", packet)
|
||||
response = packet
|
||||
return nil
|
||||
}
|
||||
}
|
||||
}
|
||||
})
|
||||
if err == errDeadlineExceeded {
|
||||
return nil, ErrNoResponse
|
||||
}
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return response, nil
|
||||
}
|
||||
|
||||
func (c *Client) retryFn(fn func(timeout time.Duration) error) error {
|
||||
timeout := c.timeout
|
||||
|
||||
// Each retry takes the amount of timeout at worst.
|
||||
for i := 0; i < c.retry || c.retry < 0; i++ { // TODO: why is this called "retry" if this is "tries" ("retries"+1)?
|
||||
switch err := fn(timeout); err {
|
||||
case nil:
|
||||
// Got it!
|
||||
return nil
|
||||
|
||||
case errDeadlineExceeded:
|
||||
// Double timeout, then retry.
|
||||
timeout *= 2
|
||||
|
||||
default:
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
return errDeadlineExceeded
|
||||
}
|
||||
|
|
@ -1,345 +0,0 @@
|
|||
// Copyright 2018 the u-root Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
// +build linux
|
||||
// github.com/hugelgupf/socketpair is Linux-only
|
||||
// +build go1.12
|
||||
|
||||
package nclient4
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"context"
|
||||
"fmt"
|
||||
"net"
|
||||
"sync"
|
||||
"testing"
|
||||
"time"
|
||||
|
||||
"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
|
||||
"github.com/hugelgupf/socketpair"
|
||||
"github.com/insomniacslk/dhcp/dhcpv4"
|
||||
"github.com/insomniacslk/dhcp/dhcpv4/server4"
|
||||
)
|
||||
|
||||
func TestMain(m *testing.M) {
|
||||
aghtest.DiscardLogOutput(m)
|
||||
}
|
||||
|
||||
type handler struct {
|
||||
mu sync.Mutex
|
||||
received []*dhcpv4.DHCPv4
|
||||
|
||||
// Each received packet can have more than one response (in theory,
|
||||
// from different servers sending different Advertise, for example).
|
||||
responses [][]*dhcpv4.DHCPv4
|
||||
}
|
||||
|
||||
func (h *handler) handle(conn net.PacketConn, peer net.Addr, m *dhcpv4.DHCPv4) {
|
||||
h.mu.Lock()
|
||||
defer h.mu.Unlock()
|
||||
|
||||
h.received = append(h.received, m)
|
||||
|
||||
if len(h.responses) > 0 {
|
||||
for _, resp := range h.responses[0] {
|
||||
_, _ = conn.WriteTo(resp.ToBytes(), peer)
|
||||
}
|
||||
h.responses = h.responses[1:]
|
||||
}
|
||||
}
|
||||
|
||||
func serveAndClient(ctx context.Context, responses [][]*dhcpv4.DHCPv4, opts ...ClientOpt) (*Client, net.PacketConn) {
|
||||
// Fake PacketConn connection.
|
||||
clientRawConn, serverRawConn, err := socketpair.PacketSocketPair()
|
||||
if err != nil {
|
||||
panic(err)
|
||||
}
|
||||
|
||||
clientConn := NewBroadcastUDPConn(clientRawConn, &net.UDPAddr{Port: ClientPort})
|
||||
serverConn := NewBroadcastUDPConn(serverRawConn, &net.UDPAddr{Port: ServerPort})
|
||||
|
||||
o := []ClientOpt{WithRetry(1), WithTimeout(2 * time.Second)}
|
||||
o = append(o, opts...)
|
||||
mc, err := NewWithConn(clientConn, net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf}, o...)
|
||||
if err != nil {
|
||||
panic(err)
|
||||
}
|
||||
|
||||
h := &handler{responses: responses}
|
||||
s, err := server4.NewServer("", nil, h.handle, server4.WithConn(serverConn))
|
||||
if err != nil {
|
||||
panic(err)
|
||||
}
|
||||
go func() {
|
||||
_ = s.Serve()
|
||||
}()
|
||||
|
||||
return mc, serverConn
|
||||
}
|
||||
|
||||
func ComparePacket(got, want *dhcpv4.DHCPv4) error {
|
||||
if got == nil && got == want {
|
||||
return nil
|
||||
}
|
||||
if (want == nil || got == nil) && (got != want) {
|
||||
return fmt.Errorf("packet got %v, want %v", got, want)
|
||||
}
|
||||
if !bytes.Equal(got.ToBytes(), want.ToBytes()) {
|
||||
return fmt.Errorf("packet got %v, want %v", got, want)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func pktsExpected(got, want []*dhcpv4.DHCPv4) error {
|
||||
if len(got) != len(want) {
|
||||
return fmt.Errorf("got %d packets, want %d packets", len(got), len(want))
|
||||
}
|
||||
|
||||
for i := range got {
|
||||
if err := ComparePacket(got[i], want[i]); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func newPacketWeirdHWAddr(op dhcpv4.OpcodeType, xid dhcpv4.TransactionID) *dhcpv4.DHCPv4 {
|
||||
p, err := dhcpv4.New()
|
||||
if err != nil {
|
||||
panic(fmt.Sprintf("newpacket: %v", err))
|
||||
}
|
||||
p.OpCode = op
|
||||
p.TransactionID = xid
|
||||
p.ClientHWAddr = net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 1, 2, 3, 4, 5, 6}
|
||||
return p
|
||||
}
|
||||
|
||||
func newPacket(op dhcpv4.OpcodeType, xid dhcpv4.TransactionID) *dhcpv4.DHCPv4 {
|
||||
p, err := dhcpv4.New()
|
||||
if err != nil {
|
||||
panic(fmt.Sprintf("newpacket: %v", err))
|
||||
}
|
||||
p.OpCode = op
|
||||
p.TransactionID = xid
|
||||
p.ClientHWAddr = net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf}
|
||||
return p
|
||||
}
|
||||
|
||||
func withBufferCap(n int) ClientOpt {
|
||||
return func(c *Client) (err error) {
|
||||
c.bufferCap = n
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
func TestSendAndRead(t *testing.T) {
|
||||
for _, tt := range []struct {
|
||||
desc string
|
||||
send *dhcpv4.DHCPv4
|
||||
server []*dhcpv4.DHCPv4
|
||||
|
||||
// If want is nil, we assume server[0] contains what is wanted.
|
||||
want *dhcpv4.DHCPv4
|
||||
wantErr error
|
||||
}{
|
||||
{
|
||||
desc: "two response packets",
|
||||
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
server: []*dhcpv4.DHCPv4{
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
want: newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
{
|
||||
desc: "one response packet",
|
||||
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
server: []*dhcpv4.DHCPv4{
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
want: newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
{
|
||||
desc: "one response packet, one invalid XID, one invalid opcode, one invalid hwaddr",
|
||||
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
server: []*dhcpv4.DHCPv4{
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x77, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacketWeirdHWAddr(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
want: newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
{
|
||||
desc: "discard wrong XID",
|
||||
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
server: []*dhcpv4.DHCPv4{
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0, 0, 0, 0}),
|
||||
},
|
||||
want: nil, // Explicitly empty.
|
||||
wantErr: ErrNoResponse,
|
||||
},
|
||||
{
|
||||
desc: "no response, timeout",
|
||||
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
wantErr: ErrNoResponse,
|
||||
},
|
||||
} {
|
||||
t.Run(tt.desc, func(t *testing.T) {
|
||||
// Both server and client only get 2 seconds.
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
|
||||
defer cancel()
|
||||
|
||||
mc, _ := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{tt.server},
|
||||
// Use an unbuffered channel to make sure we
|
||||
// have no deadlocks.
|
||||
withBufferCap(0))
|
||||
defer mc.Close()
|
||||
|
||||
rcvd, err := mc.SendAndRead(context.Background(), DefaultServers, tt.send, nil)
|
||||
if err != tt.wantErr {
|
||||
t.Error(err)
|
||||
}
|
||||
|
||||
if err = ComparePacket(rcvd, tt.want); err != nil {
|
||||
t.Errorf("got unexpected packets: %v", err)
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
func TestParallelSendAndRead(t *testing.T) {
|
||||
pkt := newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33})
|
||||
|
||||
// Both the server and client only get 2 seconds.
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
|
||||
defer cancel()
|
||||
|
||||
mc, _ := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{},
|
||||
WithTimeout(10*time.Second),
|
||||
// Use an unbuffered channel to make sure nothing blocks.
|
||||
withBufferCap(0))
|
||||
defer mc.Close()
|
||||
|
||||
var wg sync.WaitGroup
|
||||
|
||||
wg.Add(1)
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
if _, err := mc.SendAndRead(context.Background(), DefaultServers, pkt, nil); err != ErrNoResponse {
|
||||
t.Errorf("SendAndRead(%v) = %v, want %v", pkt, err, ErrNoResponse)
|
||||
}
|
||||
}()
|
||||
|
||||
wg.Add(1)
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
|
||||
time.Sleep(4 * time.Second)
|
||||
|
||||
if err := mc.Close(); err != nil {
|
||||
t.Errorf("closing failed: %v", err)
|
||||
}
|
||||
}()
|
||||
|
||||
wg.Wait()
|
||||
}
|
||||
|
||||
func TestReuseXID(t *testing.T) {
|
||||
pkt := newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33})
|
||||
|
||||
// Both the server and client only get 2 seconds.
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
|
||||
defer cancel()
|
||||
|
||||
mc, _ := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{})
|
||||
defer mc.Close()
|
||||
|
||||
if _, err := mc.SendAndRead(context.Background(), DefaultServers, pkt, nil); err != ErrNoResponse {
|
||||
t.Errorf("SendAndRead(%v) = %v, want %v", pkt, err, ErrNoResponse)
|
||||
}
|
||||
|
||||
if _, err := mc.SendAndRead(context.Background(), DefaultServers, pkt, nil); err != ErrNoResponse {
|
||||
t.Errorf("SendAndRead(%v) = %v, want %v", pkt, err, ErrNoResponse)
|
||||
}
|
||||
}
|
||||
|
||||
func TestSimpleSendAndReadDiscardGarbage(t *testing.T) {
|
||||
pkt := newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33})
|
||||
|
||||
responses := newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33})
|
||||
|
||||
// Both the server and client only get 2 seconds.
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
|
||||
defer cancel()
|
||||
|
||||
mc, udpConn := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{{responses}})
|
||||
defer mc.Close()
|
||||
|
||||
// Too short for valid DHCPv4 packet.
|
||||
_, _ = udpConn.WriteTo([]byte{0x01}, nil)
|
||||
_, _ = udpConn.WriteTo([]byte{0x01, 0x2}, nil)
|
||||
|
||||
rcvd, err := mc.SendAndRead(ctx, DefaultServers, pkt, nil)
|
||||
if err != nil {
|
||||
t.Errorf("SendAndRead(%v) = %v, want nil", pkt, err)
|
||||
}
|
||||
|
||||
if err = ComparePacket(rcvd, responses); err != nil {
|
||||
t.Errorf("got unexpected packets: %v", err)
|
||||
}
|
||||
}
|
||||
|
||||
func TestMultipleSendAndRead(t *testing.T) {
|
||||
for _, tt := range []struct {
|
||||
desc string
|
||||
send []*dhcpv4.DHCPv4
|
||||
server [][]*dhcpv4.DHCPv4
|
||||
wantErr []error
|
||||
}{
|
||||
{
|
||||
desc: "two requests, two responses",
|
||||
send: []*dhcpv4.DHCPv4{
|
||||
newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x44, 0x44, 0x44, 0x44}),
|
||||
},
|
||||
server: [][]*dhcpv4.DHCPv4{
|
||||
{ // Response for first packet.
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
|
||||
},
|
||||
{ // Response for second packet.
|
||||
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x44, 0x44, 0x44, 0x44}),
|
||||
},
|
||||
},
|
||||
wantErr: []error{
|
||||
nil,
|
||||
nil,
|
||||
},
|
||||
},
|
||||
} {
|
||||
// Both server and client only get 2 seconds.
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
|
||||
defer cancel()
|
||||
|
||||
mc, _ := serveAndClient(ctx, tt.server)
|
||||
defer mc.Close()
|
||||
|
||||
for i, send := range tt.send {
|
||||
ctx, cancel = context.WithTimeout(context.Background(), 2*time.Second)
|
||||
defer cancel()
|
||||
rcvd, err := mc.SendAndRead(ctx, DefaultServers, send, nil)
|
||||
|
||||
if wantErr := tt.wantErr[i]; err != wantErr {
|
||||
t.Errorf("SendAndReadOne(%v): got %v, want %v", send, err, wantErr)
|
||||
}
|
||||
if err = pktsExpected([]*dhcpv4.DHCPv4{rcvd}, tt.server[i]); err != nil {
|
||||
t.Errorf("got unexpected packets: %v", err)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -1,140 +0,0 @@
|
|||
// Copyright 2018 the u-root Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
// +build darwin dragonfly freebsd linux netbsd openbsd solaris
|
||||
// +build go1.12
|
||||
|
||||
package nclient4
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"io"
|
||||
"net"
|
||||
|
||||
"github.com/mdlayher/ethernet"
|
||||
"github.com/mdlayher/raw"
|
||||
"github.com/u-root/u-root/pkg/uio"
|
||||
)
|
||||
|
||||
// BroadcastMac is the broadcast MAC address.
|
||||
//
|
||||
// Any UDP packet sent to this address is broadcast on the subnet.
|
||||
var BroadcastMac = net.HardwareAddr([]byte{255, 255, 255, 255, 255, 255})
|
||||
|
||||
// ErrUDPAddrIsRequired is an error used when a passed argument is not of type "*net.UDPAddr".
|
||||
var ErrUDPAddrIsRequired = errors.New("must supply UDPAddr")
|
||||
|
||||
// NewRawUDPConn returns a UDP connection bound to the interface and port
|
||||
// given based on a raw packet socket. All packets are broadcasted.
|
||||
//
|
||||
// The interface can be completely unconfigured.
|
||||
func NewRawUDPConn(iface string, port int) (net.PacketConn, error) {
|
||||
ifc, err := net.InterfaceByName(iface)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
rawConn, err := raw.ListenPacket(ifc, uint16(ethernet.EtherTypeIPv4), &raw.Config{LinuxSockDGRAM: true})
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return NewBroadcastUDPConn(rawConn, &net.UDPAddr{Port: port}), nil
|
||||
}
|
||||
|
||||
// BroadcastRawUDPConn uses a raw socket to send UDP packets to the broadcast
|
||||
// MAC address.
|
||||
type BroadcastRawUDPConn struct {
|
||||
// PacketConn is a raw DGRAM socket.
|
||||
net.PacketConn
|
||||
|
||||
// boundAddr is the address this RawUDPConn is "bound" to.
|
||||
//
|
||||
// Calls to ReadFrom will only return packets destined to this address.
|
||||
boundAddr *net.UDPAddr
|
||||
}
|
||||
|
||||
// NewBroadcastUDPConn returns a PacketConn that marshals and unmarshals UDP
|
||||
// packets, sending them to the broadcast MAC at on rawPacketConn.
|
||||
//
|
||||
// Calls to ReadFrom will only return packets destined to boundAddr.
|
||||
func NewBroadcastUDPConn(rawPacketConn net.PacketConn, boundAddr *net.UDPAddr) net.PacketConn {
|
||||
return &BroadcastRawUDPConn{
|
||||
PacketConn: rawPacketConn,
|
||||
boundAddr: boundAddr,
|
||||
}
|
||||
}
|
||||
|
||||
func udpMatch(addr, bound *net.UDPAddr) bool {
|
||||
if bound == nil {
|
||||
return true
|
||||
}
|
||||
if bound.IP != nil && !bound.IP.Equal(addr.IP) {
|
||||
return false
|
||||
}
|
||||
return bound.Port == addr.Port
|
||||
}
|
||||
|
||||
// ReadFrom implements net.PacketConn.ReadFrom.
|
||||
//
|
||||
// ReadFrom reads raw IP packets and will try to match them against
|
||||
// upc.boundAddr. Any matching packets are returned via the given buffer.
|
||||
func (upc *BroadcastRawUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
|
||||
ipHdrMaxLen := IPv4MaximumHeaderSize
|
||||
udpHdrLen := UDPMinimumSize
|
||||
|
||||
for {
|
||||
pkt := make([]byte, ipHdrMaxLen+udpHdrLen+len(b))
|
||||
n, _, err := upc.PacketConn.ReadFrom(pkt)
|
||||
if err != nil {
|
||||
return 0, nil, err
|
||||
}
|
||||
if n == 0 {
|
||||
return 0, nil, io.EOF
|
||||
}
|
||||
pkt = pkt[:n]
|
||||
buf := uio.NewBigEndianBuffer(pkt)
|
||||
|
||||
// To read the header length, access data directly.
|
||||
ipHdr := IPv4(buf.Data())
|
||||
ipHdr = IPv4(buf.Consume(int(ipHdr.HeaderLength())))
|
||||
|
||||
if ipHdr.TransportProtocol() != UDPProtocolNumber {
|
||||
continue
|
||||
}
|
||||
udpHdr := UDP(buf.Consume(udpHdrLen))
|
||||
|
||||
addr := &net.UDPAddr{
|
||||
IP: ipHdr.DestinationAddress(),
|
||||
Port: int(udpHdr.DestinationPort()),
|
||||
}
|
||||
if !udpMatch(addr, upc.boundAddr) {
|
||||
continue
|
||||
}
|
||||
srcAddr := &net.UDPAddr{
|
||||
IP: ipHdr.SourceAddress(),
|
||||
Port: int(udpHdr.SourcePort()),
|
||||
}
|
||||
// Extra padding after end of IP packet should be ignored,
|
||||
// if not dhcp option parsing will fail.
|
||||
dhcpLen := int(ipHdr.PayloadLength()) - udpHdrLen
|
||||
return copy(b, buf.Consume(dhcpLen)), srcAddr, nil
|
||||
}
|
||||
}
|
||||
|
||||
// WriteTo implements net.PacketConn.WriteTo and broadcasts all packets at the
|
||||
// raw socket level.
|
||||
//
|
||||
// WriteTo wraps the given packet in the appropriate UDP and IP header before
|
||||
// sending it on the packet conn.
|
||||
func (upc *BroadcastRawUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
|
||||
udpAddr, ok := addr.(*net.UDPAddr)
|
||||
if !ok {
|
||||
return 0, ErrUDPAddrIsRequired
|
||||
}
|
||||
|
||||
// Using the boundAddr is not quite right here, but it works.
|
||||
packet := udp4pkt(b, udpAddr, upc.boundAddr)
|
||||
|
||||
// Broadcasting is not always right, but hell, what the ARP do I know.
|
||||
return upc.PacketConn.WriteTo(packet, &raw.Addr{HardwareAddr: BroadcastMac})
|
||||
}
|
||||
|
|
@ -1,377 +0,0 @@
|
|||
// Copyright 2018 Google LLC
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
//
|
||||
// This file contains code taken from gVisor.
|
||||
|
||||
// +build darwin dragonfly freebsd linux netbsd openbsd solaris
|
||||
// +build go1.12
|
||||
|
||||
package nclient4
|
||||
|
||||
import (
|
||||
"encoding/binary"
|
||||
"net"
|
||||
|
||||
"github.com/u-root/u-root/pkg/uio"
|
||||
)
|
||||
|
||||
const (
|
||||
versIHL = 0
|
||||
tos = 1
|
||||
totalLen = 2
|
||||
id = 4
|
||||
flagsFO = 6
|
||||
ttl = 8
|
||||
protocol = 9
|
||||
checksum = 10
|
||||
srcAddr = 12
|
||||
dstAddr = 16
|
||||
)
|
||||
|
||||
// TransportProtocolNumber is the number of a transport protocol.
|
||||
type TransportProtocolNumber uint32
|
||||
|
||||
// IPv4Fields contains the fields of an IPv4 packet. It is used to describe the
|
||||
// fields of a packet that needs to be encoded.
|
||||
type IPv4Fields struct {
|
||||
// IHL is the "internet header length" field of an IPv4 packet.
|
||||
IHL uint8
|
||||
|
||||
// TOS is the "type of service" field of an IPv4 packet.
|
||||
TOS uint8
|
||||
|
||||
// TotalLength is the "total length" field of an IPv4 packet.
|
||||
TotalLength uint16
|
||||
|
||||
// ID is the "identification" field of an IPv4 packet.
|
||||
ID uint16
|
||||
|
||||
// Flags is the "flags" field of an IPv4 packet.
|
||||
Flags uint8
|
||||
|
||||
// FragmentOffset is the "fragment offset" field of an IPv4 packet.
|
||||
FragmentOffset uint16
|
||||
|
||||
// TTL is the "time to live" field of an IPv4 packet.
|
||||
TTL uint8
|
||||
|
||||
// Protocol is the "protocol" field of an IPv4 packet.
|
||||
Protocol uint8
|
||||
|
||||
// Checksum is the "checksum" field of an IPv4 packet.
|
||||
Checksum uint16
|
||||
|
||||
// SrcAddr is the "source ip address" of an IPv4 packet.
|
||||
SrcAddr net.IP
|
||||
|
||||
// DstAddr is the "destination ip address" of an IPv4 packet.
|
||||
DstAddr net.IP
|
||||
}
|
||||
|
||||
// IPv4 represents an ipv4 header stored in a byte array.
|
||||
// Most of the methods of IPv4 access to the underlying slice without
|
||||
// checking the boundaries and could panic because of 'index out of range'.
|
||||
// Always call IsValid() to validate an instance of IPv4 before using other methods.
|
||||
type IPv4 []byte
|
||||
|
||||
const (
|
||||
// IPv4MinimumSize is the minimum size of a valid IPv4 packet.
|
||||
IPv4MinimumSize = 20
|
||||
|
||||
// IPv4MaximumHeaderSize is the maximum size of an IPv4 header. Given
|
||||
// that there are only 4 bits to represents the header length in 32-bit
|
||||
// units, the header cannot exceed 15*4 = 60 bytes.
|
||||
IPv4MaximumHeaderSize = 60
|
||||
|
||||
// IPv4AddressSize is the size, in bytes, of an IPv4 address.
|
||||
IPv4AddressSize = 4
|
||||
|
||||
// IPv4Version is the version of the ipv4 protocol.
|
||||
IPv4Version = 4
|
||||
)
|
||||
|
||||
var (
|
||||
// IPv4Broadcast is the broadcast address of the IPv4 protocol.
|
||||
IPv4Broadcast = net.IP{0xff, 0xff, 0xff, 0xff}
|
||||
|
||||
// IPv4Any is the non-routable IPv4 "any" meta address.
|
||||
IPv4Any = net.IP{0, 0, 0, 0}
|
||||
)
|
||||
|
||||
// Flags that may be set in an IPv4 packet.
|
||||
const (
|
||||
IPv4FlagMoreFragments = 1 << iota
|
||||
IPv4FlagDontFragment
|
||||
)
|
||||
|
||||
// HeaderLength returns the value of the "header length" field of the ipv4
|
||||
// header.
|
||||
func (b IPv4) HeaderLength() uint8 {
|
||||
return (b[versIHL] & 0xf) * 4
|
||||
}
|
||||
|
||||
// Protocol returns the value of the protocol field of the ipv4 header.
|
||||
func (b IPv4) Protocol() uint8 {
|
||||
return b[protocol]
|
||||
}
|
||||
|
||||
// SourceAddress returns the "source address" field of the ipv4 header.
|
||||
func (b IPv4) SourceAddress() net.IP {
|
||||
return net.IP(b[srcAddr : srcAddr+IPv4AddressSize])
|
||||
}
|
||||
|
||||
// DestinationAddress returns the "destination address" field of the ipv4
|
||||
// header.
|
||||
func (b IPv4) DestinationAddress() net.IP {
|
||||
return net.IP(b[dstAddr : dstAddr+IPv4AddressSize])
|
||||
}
|
||||
|
||||
// TransportProtocol implements Network.TransportProtocol.
|
||||
func (b IPv4) TransportProtocol() TransportProtocolNumber {
|
||||
return TransportProtocolNumber(b.Protocol())
|
||||
}
|
||||
|
||||
// Payload implements Network.Payload.
|
||||
func (b IPv4) Payload() []byte {
|
||||
return b[b.HeaderLength():][:b.PayloadLength()]
|
||||
}
|
||||
|
||||
// PayloadLength returns the length of the payload portion of the ipv4 packet.
|
||||
func (b IPv4) PayloadLength() uint16 {
|
||||
return b.TotalLength() - uint16(b.HeaderLength())
|
||||
}
|
||||
|
||||
// TotalLength returns the "total length" field of the ipv4 header.
|
||||
func (b IPv4) TotalLength() uint16 {
|
||||
return binary.BigEndian.Uint16(b[totalLen:])
|
||||
}
|
||||
|
||||
// SetTotalLength sets the "total length" field of the ipv4 header.
|
||||
func (b IPv4) SetTotalLength(totalLength uint16) {
|
||||
binary.BigEndian.PutUint16(b[totalLen:], totalLength)
|
||||
}
|
||||
|
||||
// SetChecksum sets the checksum field of the ipv4 header.
|
||||
func (b IPv4) SetChecksum(v uint16) {
|
||||
binary.BigEndian.PutUint16(b[checksum:], v)
|
||||
}
|
||||
|
||||
// SetFlagsFragmentOffset sets the "flags" and "fragment offset" fields of the
|
||||
// ipv4 header.
|
||||
func (b IPv4) SetFlagsFragmentOffset(flags uint8, offset uint16) {
|
||||
v := (uint16(flags) << 13) | (offset >> 3)
|
||||
binary.BigEndian.PutUint16(b[flagsFO:], v)
|
||||
}
|
||||
|
||||
// SetSourceAddress sets the "source address" field of the ipv4 header.
|
||||
func (b IPv4) SetSourceAddress(addr net.IP) {
|
||||
copy(b[srcAddr:srcAddr+IPv4AddressSize], addr.To4())
|
||||
}
|
||||
|
||||
// SetDestinationAddress sets the "destination address" field of the ipv4
|
||||
// header.
|
||||
func (b IPv4) SetDestinationAddress(addr net.IP) {
|
||||
copy(b[dstAddr:dstAddr+IPv4AddressSize], addr.To4())
|
||||
}
|
||||
|
||||
// CalculateChecksum calculates the checksum of the ipv4 header.
|
||||
func (b IPv4) CalculateChecksum() uint16 {
|
||||
return Checksum(b[:b.HeaderLength()], 0)
|
||||
}
|
||||
|
||||
// Encode encodes all the fields of the ipv4 header.
|
||||
func (b IPv4) Encode(i *IPv4Fields) {
|
||||
b[versIHL] = (4 << 4) | ((i.IHL / 4) & 0xf)
|
||||
b[tos] = i.TOS
|
||||
b.SetTotalLength(i.TotalLength)
|
||||
binary.BigEndian.PutUint16(b[id:], i.ID)
|
||||
b.SetFlagsFragmentOffset(i.Flags, i.FragmentOffset)
|
||||
b[ttl] = i.TTL
|
||||
b[protocol] = i.Protocol
|
||||
b.SetChecksum(i.Checksum)
|
||||
copy(b[srcAddr:srcAddr+IPv4AddressSize], i.SrcAddr)
|
||||
copy(b[dstAddr:dstAddr+IPv4AddressSize], i.DstAddr)
|
||||
}
|
||||
|
||||
const (
|
||||
udpSrcPort = 0
|
||||
udpDstPort = 2
|
||||
udpLength = 4
|
||||
udpChecksum = 6
|
||||
)
|
||||
|
||||
// UDPFields contains the fields of a UDP packet. It is used to describe the
|
||||
// fields of a packet that needs to be encoded.
|
||||
type UDPFields struct {
|
||||
// SrcPort is the "source port" field of a UDP packet.
|
||||
SrcPort uint16
|
||||
|
||||
// DstPort is the "destination port" field of a UDP packet.
|
||||
DstPort uint16
|
||||
|
||||
// Length is the "length" field of a UDP packet.
|
||||
Length uint16
|
||||
|
||||
// Checksum is the "checksum" field of a UDP packet.
|
||||
Checksum uint16
|
||||
}
|
||||
|
||||
// UDP represents a UDP header stored in a byte array.
|
||||
type UDP []byte
|
||||
|
||||
const (
|
||||
// UDPMinimumSize is the minimum size of a valid UDP packet.
|
||||
UDPMinimumSize = 8
|
||||
|
||||
// UDPProtocolNumber is UDP's transport protocol number.
|
||||
UDPProtocolNumber TransportProtocolNumber = 17
|
||||
)
|
||||
|
||||
// SourcePort returns the "source port" field of the udp header.
|
||||
func (b UDP) SourcePort() uint16 {
|
||||
return binary.BigEndian.Uint16(b[udpSrcPort:])
|
||||
}
|
||||
|
||||
// DestinationPort returns the "destination port" field of the udp header.
|
||||
func (b UDP) DestinationPort() uint16 {
|
||||
return binary.BigEndian.Uint16(b[udpDstPort:])
|
||||
}
|
||||
|
||||
// Length returns the "length" field of the udp header.
|
||||
func (b UDP) Length() uint16 {
|
||||
return binary.BigEndian.Uint16(b[udpLength:])
|
||||
}
|
||||
|
||||
// SetSourcePort sets the "source port" field of the udp header.
|
||||
func (b UDP) SetSourcePort(port uint16) {
|
||||
binary.BigEndian.PutUint16(b[udpSrcPort:], port)
|
||||
}
|
||||
|
||||
// SetDestinationPort sets the "destination port" field of the udp header.
|
||||
func (b UDP) SetDestinationPort(port uint16) {
|
||||
binary.BigEndian.PutUint16(b[udpDstPort:], port)
|
||||
}
|
||||
|
||||
// SetChecksum sets the "checksum" field of the udp header.
|
||||
func (b UDP) SetChecksum(checksum uint16) {
|
||||
binary.BigEndian.PutUint16(b[udpChecksum:], checksum)
|
||||
}
|
||||
|
||||
// Payload returns the data contained in the UDP datagram.
|
||||
func (b UDP) Payload() []byte {
|
||||
return b[UDPMinimumSize:]
|
||||
}
|
||||
|
||||
// Checksum returns the "checksum" field of the udp header.
|
||||
func (b UDP) Checksum() uint16 {
|
||||
return binary.BigEndian.Uint16(b[udpChecksum:])
|
||||
}
|
||||
|
||||
// CalculateChecksum calculates the checksum of the udp packet, given the total
|
||||
// length of the packet and the checksum of the network-layer pseudo-header
|
||||
// (excluding the total length) and the checksum of the payload.
|
||||
func (b UDP) CalculateChecksum(partialChecksum, totalLen uint16) uint16 {
|
||||
// Add the length portion of the checksum to the pseudo-checksum.
|
||||
tmp := make([]byte, 2)
|
||||
binary.BigEndian.PutUint16(tmp, totalLen)
|
||||
checksum := Checksum(tmp, partialChecksum)
|
||||
|
||||
// Calculate the rest of the checksum.
|
||||
return Checksum(b[:UDPMinimumSize], checksum)
|
||||
}
|
||||
|
||||
// Encode encodes all the fields of the udp header.
|
||||
func (b UDP) Encode(u *UDPFields) {
|
||||
binary.BigEndian.PutUint16(b[udpSrcPort:], u.SrcPort)
|
||||
binary.BigEndian.PutUint16(b[udpDstPort:], u.DstPort)
|
||||
binary.BigEndian.PutUint16(b[udpLength:], u.Length)
|
||||
binary.BigEndian.PutUint16(b[udpChecksum:], u.Checksum)
|
||||
}
|
||||
|
||||
func calculateChecksum(buf []byte, initial uint32) uint16 {
|
||||
v := initial
|
||||
|
||||
l := len(buf)
|
||||
if l&1 != 0 {
|
||||
l--
|
||||
v += uint32(buf[l]) << 8
|
||||
}
|
||||
|
||||
for i := 0; i < l; i += 2 {
|
||||
v += (uint32(buf[i]) << 8) + uint32(buf[i+1])
|
||||
}
|
||||
|
||||
return ChecksumCombine(uint16(v), uint16(v>>16))
|
||||
}
|
||||
|
||||
// Checksum calculates the checksum (as defined in RFC 1071) of the bytes in the
|
||||
// given byte array.
|
||||
//
|
||||
// The initial checksum must have been computed on an even number of bytes.
|
||||
func Checksum(buf []byte, initial uint16) uint16 {
|
||||
return calculateChecksum(buf, uint32(initial))
|
||||
}
|
||||
|
||||
// ChecksumCombine combines the two uint16 to form their checksum. This is done
|
||||
// by adding them and the carry.
|
||||
//
|
||||
// Note that checksum a must have been computed on an even number of bytes.
|
||||
func ChecksumCombine(a, b uint16) uint16 {
|
||||
v := uint32(a) + uint32(b)
|
||||
return uint16(v + v>>16)
|
||||
}
|
||||
|
||||
// PseudoHeaderChecksum calculates the pseudo-header checksum for the
|
||||
// given destination protocol and network address, ignoring the length
|
||||
// field. Pseudo-headers are needed by transport layers when calculating
|
||||
// their own checksum.
|
||||
func PseudoHeaderChecksum(protocol TransportProtocolNumber, srcAddr, dstAddr net.IP) uint16 {
|
||||
xsum := Checksum([]byte(srcAddr), 0)
|
||||
xsum = Checksum([]byte(dstAddr), xsum)
|
||||
return Checksum([]byte{0, uint8(protocol)}, xsum)
|
||||
}
|
||||
|
||||
func udp4pkt(packet []byte, dest, src *net.UDPAddr) []byte {
|
||||
ipLen := IPv4MinimumSize
|
||||
udpLen := UDPMinimumSize
|
||||
|
||||
h := make([]byte, 0, ipLen+udpLen+len(packet))
|
||||
hdr := uio.NewBigEndianBuffer(h)
|
||||
|
||||
ipv4fields := &IPv4Fields{
|
||||
IHL: IPv4MinimumSize,
|
||||
TotalLength: uint16(ipLen + udpLen + len(packet)),
|
||||
TTL: 64, // Per RFC 1700's recommendation for IP time to live
|
||||
Protocol: uint8(UDPProtocolNumber),
|
||||
SrcAddr: src.IP.To4(),
|
||||
DstAddr: dest.IP.To4(),
|
||||
}
|
||||
ipv4hdr := IPv4(hdr.WriteN(ipLen))
|
||||
ipv4hdr.Encode(ipv4fields)
|
||||
ipv4hdr.SetChecksum(^ipv4hdr.CalculateChecksum())
|
||||
|
||||
udphdr := UDP(hdr.WriteN(udpLen))
|
||||
udphdr.Encode(&UDPFields{
|
||||
SrcPort: uint16(src.Port),
|
||||
DstPort: uint16(dest.Port),
|
||||
Length: uint16(udpLen + len(packet)),
|
||||
})
|
||||
|
||||
xsum := Checksum(packet, PseudoHeaderChecksum(
|
||||
ipv4hdr.TransportProtocol(), ipv4fields.SrcAddr, ipv4fields.DstAddr))
|
||||
udphdr.SetChecksum(^udphdr.CalculateChecksum(xsum, udphdr.Length()))
|
||||
|
||||
hdr.WriteBytes(packet)
|
||||
return hdr.Data()
|
||||
}
|
||||
Loading…
Reference in New Issue