74 lines
2.2 KiB
Go
74 lines
2.2 KiB
Go
/*
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Copyright 2024 Josh Deprez
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package router
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import (
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"context"
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"fmt"
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"github.com/sfiera/multitalk/pkg/ddp"
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)
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type Router struct {
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Config *Config
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RouteTable *RouteTable
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ZoneTable *ZoneTable
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Ports []*EtherTalkPort
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}
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// Forward increments the hop count, then outputs the packet in the direction
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// of the destination.
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func (rtr *Router) Forward(ctx context.Context, ddpkt *ddp.ExtPacket) error {
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// Check and adjust the Hop Count
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// Note the ddp package doesn't make this simple
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hopCount := (ddpkt.Size & 0x3C00) >> 10
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if hopCount >= 15 {
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return fmt.Errorf("hop count exceeded (%d >= 15)", hopCount)
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}
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hopCount++
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ddpkt.Size &^= 0x3C00
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ddpkt.Size |= hopCount << 10
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return rtr.Output(ctx, ddpkt)
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}
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// Output outputs the packet in the direction of the destination.
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// (It does not check or adjust the hop count.)
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func (rtr *Router) Output(ctx context.Context, ddpkt *ddp.ExtPacket) error {
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switch route := rtr.RouteTable.LookupRoute(ddpkt.DstNet); {
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case route == nil:
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return fmt.Errorf("no route for packet (dstnet %d); dropping packet", ddpkt.DstNet)
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case route.AURPPeer != nil:
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// log.Printf("Forwarding packet to AURP peer %v", route.AURPPeer.RemoteAddr)
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return route.AURPPeer.Forward(ddpkt)
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case route.EtherTalkPeer != nil:
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// log.Printf("Forwarding to EtherTalk peer %v", route.EtherTalkPeer.PeerAddr)
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// Note: resolving AARP can block
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return route.EtherTalkPeer.Forward(ctx, ddpkt)
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case route.EtherTalkDirect != nil:
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// log.Printf("Outputting to EtherTalk directly")
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// Note: resolving AARP can block
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return route.EtherTalkDirect.Send(ctx, ddpkt)
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default:
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return fmt.Errorf("no forwarding mechanism for route! %+v", route)
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}
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}
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