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| 1 | +package filters |
| 2 | + |
| 3 | +import ( |
| 4 | + "encoding/binary" |
| 5 | + |
| 6 | + "github.com/pkg/errors" |
| 7 | + log "github.com/sirupsen/logrus" |
| 8 | + |
| 9 | + "github.com/brocaar/lora-gateway-bridge/internal/config" |
| 10 | + "github.com/brocaar/lorawan" |
| 11 | +) |
| 12 | + |
| 13 | +var netIDs []lorawan.NetID |
| 14 | +var joinEUIs [][2]lorawan.EUI64 |
| 15 | + |
| 16 | +func Setup(conf config.Config) error { |
| 17 | + for _, netIDStr := range conf.Filters.NetIDs { |
| 18 | + var netID lorawan.NetID |
| 19 | + if err := netID.UnmarshalText([]byte(netIDStr)); err != nil { |
| 20 | + return errors.Wrap(err, "unmarshal NetID error") |
| 21 | + } |
| 22 | + |
| 23 | + netIDs = append(netIDs, netID) |
| 24 | + log.WithFields(log.Fields{ |
| 25 | + "net_id": netID, |
| 26 | + }).Info("filters: NetID filter configured") |
| 27 | + } |
| 28 | + |
| 29 | + for _, set := range conf.Filters.JoinEUIs { |
| 30 | + var joinEUISet [2]lorawan.EUI64 |
| 31 | + |
| 32 | + for i, s := range set { |
| 33 | + var joinEUI lorawan.EUI64 |
| 34 | + if err := joinEUI.UnmarshalText([]byte(s)); err != nil { |
| 35 | + return errors.Wrap(err, "unmarshal JoinEUI error") |
| 36 | + } |
| 37 | + |
| 38 | + joinEUISet[i] = joinEUI |
| 39 | + } |
| 40 | + |
| 41 | + joinEUIs = append(joinEUIs, joinEUISet) |
| 42 | + |
| 43 | + log.WithFields(log.Fields{ |
| 44 | + "join_eui_from": joinEUISet[0], |
| 45 | + "join_eui_to": joinEUISet[1], |
| 46 | + }).Info("filters: JoinEUI range configured") |
| 47 | + } |
| 48 | + |
| 49 | + return nil |
| 50 | +} |
| 51 | + |
| 52 | +// MatchFilters will match the given LoRaWAN frame against the configured |
| 53 | +// filters. This function returns true in the following cases: |
| 54 | +// * If the PHYPayload matches the configured filters |
| 55 | +// * If no filters are configured |
| 56 | +// * In case the PHYPayload is not a valid LoRaWAN frame |
| 57 | +func MatchFilters(b []byte) bool { |
| 58 | + // return true when no filters are configured |
| 59 | + if len(netIDs) == 0 && len(joinEUIs) == 0 { |
| 60 | + return true |
| 61 | + } |
| 62 | + |
| 63 | + // return true when we can't decode the LoRaWAN frame |
| 64 | + var phy lorawan.PHYPayload |
| 65 | + if err := phy.UnmarshalBinary(b); err != nil { |
| 66 | + log.WithError(err).Error("filters: unmarshal phypayload error") |
| 67 | + return true |
| 68 | + } |
| 69 | + |
| 70 | + switch phy.MHDR.MType { |
| 71 | + case lorawan.UnconfirmedDataUp, lorawan.ConfirmedDataUp: |
| 72 | + return filterDevAddr(phy) |
| 73 | + case lorawan.JoinRequest: |
| 74 | + return filterJoinRequest(phy) |
| 75 | + case lorawan.RejoinRequest: |
| 76 | + return filterRejoinRequest(phy) |
| 77 | + default: |
| 78 | + return true |
| 79 | + } |
| 80 | +} |
| 81 | + |
| 82 | +func matchNetIDFilter(netID lorawan.NetID) bool { |
| 83 | + if len(netIDs) == 0 { |
| 84 | + return true |
| 85 | + } |
| 86 | + |
| 87 | + for _, n := range netIDs { |
| 88 | + if n == netID { |
| 89 | + return true |
| 90 | + } |
| 91 | + } |
| 92 | + |
| 93 | + return false |
| 94 | +} |
| 95 | + |
| 96 | +func matchNetIDFilterForDevAddr(devAddr lorawan.DevAddr) bool { |
| 97 | + if len(netIDs) == 0 { |
| 98 | + return true |
| 99 | + } |
| 100 | + |
| 101 | + for _, netID := range netIDs { |
| 102 | + if devAddr.IsNetID(netID) { |
| 103 | + return true |
| 104 | + } |
| 105 | + } |
| 106 | + |
| 107 | + return false |
| 108 | +} |
| 109 | + |
| 110 | +func matchJoinEUIFilter(joinEUI lorawan.EUI64) bool { |
| 111 | + if len(joinEUIs) == 0 { |
| 112 | + return true |
| 113 | + } |
| 114 | + |
| 115 | + joinEUIInt := binary.BigEndian.Uint64(joinEUI[:]) |
| 116 | + |
| 117 | + for _, pair := range joinEUIs { |
| 118 | + min := binary.BigEndian.Uint64(pair[0][:]) |
| 119 | + max := binary.BigEndian.Uint64(pair[1][:]) |
| 120 | + |
| 121 | + if joinEUIInt >= min && joinEUIInt <= max { |
| 122 | + return true |
| 123 | + } |
| 124 | + } |
| 125 | + |
| 126 | + return false |
| 127 | +} |
| 128 | + |
| 129 | +func filterDevAddr(phy lorawan.PHYPayload) bool { |
| 130 | + mac, ok := phy.MACPayload.(*lorawan.MACPayload) |
| 131 | + if !ok { |
| 132 | + return true |
| 133 | + } |
| 134 | + |
| 135 | + return matchNetIDFilterForDevAddr(mac.FHDR.DevAddr) |
| 136 | +} |
| 137 | + |
| 138 | +func filterJoinRequest(phy lorawan.PHYPayload) bool { |
| 139 | + jr, ok := phy.MACPayload.(*lorawan.JoinRequestPayload) |
| 140 | + if !ok { |
| 141 | + return true |
| 142 | + } |
| 143 | + |
| 144 | + return matchJoinEUIFilter(jr.JoinEUI) |
| 145 | +} |
| 146 | + |
| 147 | +func filterRejoinRequest(phy lorawan.PHYPayload) bool { |
| 148 | + switch v := phy.MACPayload.(type) { |
| 149 | + case *lorawan.RejoinRequestType02Payload: |
| 150 | + return matchNetIDFilter(v.NetID) |
| 151 | + case *lorawan.RejoinRequestType1Payload: |
| 152 | + return matchJoinEUIFilter(v.JoinEUI) |
| 153 | + default: |
| 154 | + return true |
| 155 | + } |
| 156 | +} |
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