├── go.mod ├── .gitignore ├── .github └── workflows │ └── main.yml ├── netfilter.c ├── netfilter_test.go ├── go.sum ├── README.md ├── netfilter.h ├── netfilter.go └── LICENSE /go.mod: -------------------------------------------------------------------------------- 1 | module github.com/AkihiroSuda/go-netfilter-queue 2 | 3 | go 1.15 4 | 5 | require github.com/google/gopacket v1.1.19 6 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled Object files, Static and Dynamic libs (Shared Objects) 2 | *.o 3 | *.a 4 | *.so 5 | 6 | # Folders 7 | _obj 8 | _test 9 | 10 | # Architecture specific extensions/prefixes 11 | *.[568vq] 12 | [568vq].out 13 | 14 | *.cgo1.go 15 | *.cgo2.c 16 | _cgo_defun.c 17 | _cgo_gotypes.go 18 | _cgo_export.* 19 | 20 | _testmain.go 21 | 22 | *.exe 23 | -------------------------------------------------------------------------------- /.github/workflows/main.yml: -------------------------------------------------------------------------------- 1 | name: CI 2 | on: 3 | push: 4 | branches: 5 | - master 6 | pull_request: 7 | jobs: 8 | main: 9 | runs-on: ubuntu-22.04 10 | steps: 11 | - uses: actions/setup-go@v3 12 | with: 13 | go-version: 1.20.x 14 | - uses: actions/checkout@v3 15 | - run: sudo apt-get update && sudo apt-get install -y libnetfilter-queue-dev 16 | - run: go test -exec sudo -covermode=atomic -race -v ./... 17 | # TODO: enable golangci-lint 18 | # - name: golangci-lint 19 | # uses: golangci/golangci-lint-action@v3.4.0 20 | # with: 21 | # version: v1.51.2 22 | # args: --verbose 23 | -------------------------------------------------------------------------------- /netfilter.c: -------------------------------------------------------------------------------- 1 | /* 2 | Copyright 2014 Krishna Raman 3 | 4 | Licensed under the Apache License, Version 2.0 (the "License"); 5 | you may not use this file except in compliance with the License. 6 | You may obtain a copy of the License at 7 | 8 | http://www.apache.org/licenses/LICENSE-2.0 9 | 10 | Unless required by applicable law or agreed to in writing, software 11 | distributed under the License is distributed on an "AS IS" BASIS, 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | See the License for the specific language governing permissions and 14 | limitations under the License. 15 | */ 16 | 17 | #include "netfilter.h" 18 | 19 | -------------------------------------------------------------------------------- /netfilter_test.go: -------------------------------------------------------------------------------- 1 | package netfilter 2 | 3 | import ( 4 | "testing" 5 | "time" 6 | ) 7 | 8 | var stopCh = make(chan struct{}) 9 | 10 | func serve(t *testing.T, queueNum uint16) { 11 | nfq, err := NewNFQueue(queueNum, 100, NF_DEFAULT_PACKET_SIZE) 12 | if err != nil { 13 | t.Skipf("Skipping the test due to %s", err) 14 | } 15 | defer nfq.Close() 16 | packets := nfq.GetPackets() 17 | 18 | t.Logf("Starting (NFQ %d)..", queueNum) 19 | for true { 20 | select { 21 | case p := <-packets: 22 | t.Logf("Accepting %s", p.Packet) 23 | p.SetVerdict(NF_ACCEPT) 24 | case <-stopCh: 25 | t.Logf("Exiting..") 26 | return 27 | } 28 | } 29 | } 30 | 31 | // very dumb test, but enough for testing golang/go#14210 32 | func TestNetfilter(t *testing.T) { 33 | queueNum := 42 34 | go serve(t, uint16(queueNum)) 35 | wait := 3 * time.Second 36 | t.Logf("Sleeping for %s", wait) 37 | time.Sleep(wait) 38 | close(stopCh) 39 | } 40 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- 1 | github.com/google/gopacket v1.1.19 h1:ves8RnFZPGiFnTS0uPQStjwru6uO6h+nlr9j6fL7kF8= 2 | github.com/google/gopacket v1.1.19/go.mod h1:iJ8V8n6KS+z2U1A8pUwu8bW5SyEMkXJB8Yo/Vo+TKTo= 3 | golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= 4 | golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI= 5 | golang.org/x/lint v0.0.0-20200302205851-738671d3881b/go.mod h1:3xt1FjdF8hUf6vQPIChWIBhFzV8gjjsPE/fR3IyQdNY= 6 | golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg= 7 | golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= 8 | golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= 9 | golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= 10 | golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= 11 | golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 12 | golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= 13 | golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28= 14 | golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= 15 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | go-netfilter-queue 2 | ================== 3 | [![GoDoc](https://godoc.org/github.com/AkihiroSuda/go-netfilter-queue?status.svg)](https://godoc.org/github.com/AkihiroSuda/go-netfilter-queue) 4 | 5 | Go bindings for libnetfilter_queue 6 | 7 | _Forked from [openshift/geard@be0423a](https://github.com/openshift/geard/tree/be0423a67449bc4be1419e03e8bdf459ff0df07e/pkg/go-netfilter-queue)_ for supporting recent environments. 8 | 9 | This library provides access to packets in the IPTables netfilter queue (NFQUEUE). 10 | The libnetfilter_queue library is part of the [Netfilter project](http://netfilter.org/projects/libnetfilter_queue/). 11 | 12 | Example 13 | ======= 14 | 15 | use IPTables to direct all outgoing Ping/ICMP requests to the queue 0: 16 | 17 | iptables -A OUTPUT -p icmp -j NFQUEUE --queue-num 0 18 | 19 | You can then use go-netfilter-queue to inspect the packets: 20 | 21 | package main 22 | 23 | import ( 24 | "fmt" 25 | "github.com/AkihiroSuda/go-netfilter-queue" 26 | "os" 27 | ) 28 | 29 | func main() { 30 | var err error 31 | 32 | nfq, err := netfilter.NewNFQueue(0, 100, netfilter.NF_DEFAULT_PACKET_SIZE) 33 | if err != nil { 34 | fmt.Println(err) 35 | os.Exit(1) 36 | } 37 | defer nfq.Close() 38 | packets := nfq.GetPackets() 39 | 40 | for true { 41 | select { 42 | case p := <-packets: 43 | fmt.Println(p.Packet) 44 | p.SetVerdict(netfilter.NF_ACCEPT) 45 | } 46 | } 47 | } 48 | 49 | To inject a new or modified packet in the place of the original packet, use: 50 | 51 | p.SetVerdictWithPacket(netfilter.NF_ACCEPT, byte_slice) 52 | 53 | Instead of: 54 | 55 | p.SetVerdict(netfilter.NF_ACCEPT) 56 | 57 | To undo the IPTables redirect. Run: 58 | 59 | iptables -D OUTPUT -p icmp -j NFQUEUE --queue-num 0 60 | -------------------------------------------------------------------------------- /netfilter.h: -------------------------------------------------------------------------------- 1 | /* 2 | Copyright 2014 Krishna Raman 3 | 4 | Licensed under the Apache License, Version 2.0 (the "License"); 5 | you may not use this file except in compliance with the License. 6 | You may obtain a copy of the License at 7 | 8 | http://www.apache.org/licenses/LICENSE-2.0 9 | 10 | Unless required by applicable law or agreed to in writing, software 11 | distributed under the License is distributed on an "AS IS" BASIS, 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | See the License for the specific language governing permissions and 14 | limitations under the License. 15 | */ 16 | 17 | #ifndef _NETFILTER_H 18 | #define _NETFILTER_H 19 | 20 | #include 21 | #include 22 | #include 23 | #include 24 | #include 25 | #include 26 | #include 27 | #include 28 | #include 29 | #include 30 | #include 31 | #include 32 | 33 | extern void go_callback( 34 | uint32_t id, 35 | unsigned char* data, 36 | int len, 37 | u_int32_t mark, 38 | u_int32_t idx, 39 | struct nfq_q_handle* qh 40 | ); 41 | 42 | static int nf_callback(struct nfq_q_handle *qh, struct nfgenmsg *nfmsg, struct nfq_data *nfa, void *cb_func){ 43 | uint32_t id = -1; 44 | struct nfqnl_msg_packet_hdr *ph = NULL; 45 | unsigned char *buffer = NULL; 46 | int ret = 0; 47 | int mark = 0; 48 | u_int32_t idx; 49 | 50 | ph = nfq_get_msg_packet_hdr(nfa); 51 | id = ntohl(ph->packet_id); 52 | 53 | ret = nfq_get_payload(nfa, &buffer); 54 | idx = (uint32_t)((uintptr_t)cb_func); 55 | 56 | mark = nfq_get_nfmark(nfa); 57 | 58 | go_callback(id, buffer, ret, mark, idx, qh); 59 | return 0; 60 | } 61 | 62 | static inline struct nfq_q_handle* CreateQueue(struct nfq_handle *h, u_int16_t queue, u_int32_t idx) 63 | { 64 | return nfq_create_queue(h, queue, &nf_callback, (void*)((uintptr_t)idx)); 65 | } 66 | 67 | static inline int Run(struct nfq_handle *h, int fd) 68 | { 69 | char buf[4096] __attribute__ ((aligned)); 70 | int rv; 71 | 72 | int opt = 1; 73 | setsockopt(fd, SOL_NETLINK, NETLINK_NO_ENOBUFS, &opt, sizeof(int)); 74 | 75 | while ((rv = recv(fd, buf, sizeof(buf), 0)) && rv >= 0) { 76 | nfq_handle_packet(h, buf, rv); 77 | } 78 | 79 | return errno; 80 | } 81 | 82 | #endif 83 | -------------------------------------------------------------------------------- /netfilter.go: -------------------------------------------------------------------------------- 1 | /* 2 | Copyright 2014 Krishna Raman 3 | 4 | Licensed under the Apache License, Version 2.0 (the "License"); 5 | you may not use this file except in compliance with the License. 6 | You may obtain a copy of the License at 7 | 8 | http://www.apache.org/licenses/LICENSE-2.0 9 | 10 | Unless required by applicable law or agreed to in writing, software 11 | distributed under the License is distributed on an "AS IS" BASIS, 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | See the License for the specific language governing permissions and 14 | limitations under the License. 15 | */ 16 | 17 | /* 18 | Go bindings for libnetfilter_queue 19 | 20 | This library provides access to packets in the IPTables netfilter queue (NFQUEUE). 21 | The libnetfilter_queue library is part of the http://netfilter.org/projects/libnetfilter_queue/ project. 22 | */ 23 | package netfilter 24 | 25 | /* 26 | #cgo pkg-config: libnetfilter_queue 27 | #cgo CFLAGS: -Wall -I/usr/include 28 | #cgo LDFLAGS: -L/usr/lib64/ 29 | 30 | #include "netfilter.h" 31 | */ 32 | import "C" 33 | 34 | import ( 35 | "fmt" 36 | "os" 37 | "sync" 38 | "time" 39 | "unsafe" 40 | 41 | "github.com/google/gopacket" 42 | "github.com/google/gopacket/layers" 43 | ) 44 | 45 | //Verdict for a packet 46 | type Verdict C.uint 47 | 48 | type NFPacket struct { 49 | Packet gopacket.Packet 50 | Mark uint32 51 | qh *C.struct_nfq_q_handle 52 | id C.uint32_t 53 | } 54 | 55 | //Set the verdict for the packet 56 | func (p *NFPacket) SetVerdict(v Verdict) { 57 | C.nfq_set_verdict(p.qh, p.id, C.uint(v), 0, nil) 58 | } 59 | 60 | //Set the verdict for the packet with a mark 61 | func (p *NFPacket) SetVerdictMark(v Verdict, mark uint32) { 62 | C.nfq_set_verdict2(p.qh, p.id, C.uint(v), C.uint32_t(mark), 0, nil) 63 | } 64 | 65 | 66 | //Set the verdict for the packet (in the case of requeue) 67 | func (p *NFPacket) SetRequeueVerdict(newQueueId uint16) { 68 | v := uint(NF_QUEUE) 69 | q := (uint(newQueueId) << 16) 70 | v = v | q 71 | C.nfq_set_verdict(p.qh, p.id, C.uint(v), 0, nil) 72 | } 73 | 74 | //Set the verdict for the packet AND provide new packet content for injection 75 | func (p *NFPacket) SetVerdictWithPacket(v Verdict, packet []byte) { 76 | C.nfq_set_verdict( 77 | p.qh, 78 | p.id, 79 | C.uint(v), 80 | C.uint(len(packet)), 81 | (*C.uchar)(unsafe.Pointer(&packet[0])), 82 | ) 83 | } 84 | 85 | type NFQueue struct { 86 | h *C.struct_nfq_handle 87 | qh *C.struct_nfq_q_handle 88 | fd C.int 89 | packets chan NFPacket 90 | idx uint32 91 | } 92 | 93 | const ( 94 | AF_INET = 2 95 | AF_INET6 = 10 96 | 97 | NF_DROP Verdict = 0 98 | NF_ACCEPT Verdict = 1 99 | NF_STOLEN Verdict = 2 100 | NF_QUEUE Verdict = 3 101 | NF_REPEAT Verdict = 4 102 | NF_STOP Verdict = 5 103 | 104 | NF_DEFAULT_PACKET_SIZE uint32 = 0xffff 105 | 106 | ipv4version = 0x40 107 | ) 108 | 109 | var theTable = make(map[uint32]*chan NFPacket, 0) 110 | var theTabeLock sync.RWMutex 111 | 112 | //Create and bind to queue specified by queueId 113 | func NewNFQueue(queueId uint16, maxPacketsInQueue uint32, packetSize uint32) (*NFQueue, error) { 114 | var nfq = NFQueue{} 115 | var err error 116 | var ret C.int 117 | 118 | if nfq.h, err = C.nfq_open(); err != nil { 119 | return nil, fmt.Errorf("Error opening NFQueue handle: %v\n", err) 120 | } 121 | 122 | if ret, err = C.nfq_unbind_pf(nfq.h, AF_INET); err != nil || ret < 0 { 123 | return nil, fmt.Errorf("Error unbinding existing NFQ handler from AF_INET protocol family: %v\n", err) 124 | } 125 | 126 | if ret, err = C.nfq_unbind_pf(nfq.h, AF_INET6); err != nil || ret < 0 { 127 | return nil, fmt.Errorf("Error unbinding existing NFQ handler from AF_INET6 protocol family: %v\n", err) 128 | } 129 | 130 | if ret, err := C.nfq_bind_pf(nfq.h, AF_INET); err != nil || ret < 0 { 131 | return nil, fmt.Errorf("Error binding to AF_INET protocol family: %v\n", err) 132 | } 133 | 134 | if ret, err := C.nfq_bind_pf(nfq.h, AF_INET6); err != nil || ret < 0 { 135 | return nil, fmt.Errorf("Error binding to AF_INET6 protocol family: %v\n", err) 136 | } 137 | 138 | nfq.packets = make(chan NFPacket, maxPacketsInQueue) 139 | nfq.idx = uint32(time.Now().UnixNano()) 140 | theTabeLock.Lock() 141 | theTable[nfq.idx] = &nfq.packets 142 | theTabeLock.Unlock() 143 | if nfq.qh, err = C.CreateQueue(nfq.h, C.u_int16_t(queueId), C.u_int32_t(nfq.idx)); err != nil || nfq.qh == nil { 144 | C.nfq_close(nfq.h) 145 | return nil, fmt.Errorf("Error binding to queue: %v\n", err) 146 | } 147 | 148 | if ret, err = C.nfq_set_queue_maxlen(nfq.qh, C.u_int32_t(maxPacketsInQueue)); err != nil || ret < 0 { 149 | C.nfq_destroy_queue(nfq.qh) 150 | C.nfq_close(nfq.h) 151 | return nil, fmt.Errorf("Unable to set max packets in queue: %v\n", err) 152 | } 153 | 154 | if C.nfq_set_mode(nfq.qh, C.u_int8_t(2), C.uint(packetSize)) < 0 { 155 | C.nfq_destroy_queue(nfq.qh) 156 | C.nfq_close(nfq.h) 157 | return nil, fmt.Errorf("Unable to set packets copy mode: %v\n", err) 158 | } 159 | 160 | if nfq.fd, err = C.nfq_fd(nfq.h); err != nil { 161 | C.nfq_destroy_queue(nfq.qh) 162 | C.nfq_close(nfq.h) 163 | return nil, fmt.Errorf("Unable to get queue file-descriptor. %v\n", err) 164 | } 165 | 166 | go nfq.run() 167 | 168 | return &nfq, nil 169 | } 170 | 171 | //Unbind and close the queue 172 | func (nfq *NFQueue) Close() { 173 | C.nfq_destroy_queue(nfq.qh) 174 | C.nfq_close(nfq.h) 175 | theTabeLock.Lock() 176 | close(nfq.packets) 177 | delete(theTable, nfq.idx) 178 | theTabeLock.Unlock() 179 | } 180 | 181 | //Get the channel for packets 182 | func (nfq *NFQueue) GetPackets() <-chan NFPacket { 183 | return nfq.packets 184 | } 185 | 186 | func (nfq *NFQueue) run() { 187 | if errno := C.Run(nfq.h, nfq.fd); errno != 0 { 188 | fmt.Fprintf(os.Stderr, "Terminating, unable to receive packet due to errno=%d\n", errno) 189 | } 190 | } 191 | 192 | //export go_callback 193 | func go_callback(packetId C.uint32_t, data *C.uchar, length C.int, mark C.uint32_t, idx uint32, qh *C.struct_nfq_q_handle) { 194 | xdata := C.GoBytes(unsafe.Pointer(data), length) 195 | 196 | var packet gopacket.Packet 197 | if xdata[0]&0xf0 == ipv4version { 198 | packet = gopacket.NewPacket(xdata, layers.LayerTypeIPv4, gopacket.DecodeOptions{Lazy: true, NoCopy: true}) 199 | } else { 200 | packet = gopacket.NewPacket(xdata, layers.LayerTypeIPv6, gopacket.DecodeOptions{Lazy: true, NoCopy: true}) 201 | } 202 | 203 | p := NFPacket{ 204 | Packet: packet, 205 | qh: qh, 206 | id: packetId, 207 | Mark: uint32(mark), 208 | } 209 | 210 | theTabeLock.RLock() 211 | cb, ok := theTable[idx] 212 | theTabeLock.RUnlock() 213 | if !ok { 214 | fmt.Fprintf(os.Stderr, "Dropping, unexpectedly due to bad idx=%d\n", idx) 215 | p.SetVerdict(NF_DROP) 216 | } 217 | 218 | // Nonblocking write of packet to queue channel 219 | select { 220 | case *cb <- p: 221 | default: 222 | fmt.Fprintf(os.Stderr, "Dropping, unexpectedly due to no recv, idx=%d\n", idx) 223 | p.SetVerdict(NF_DROP) 224 | } 225 | } 226 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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