mirror of
https://github.com/slackhq/nebula.git
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66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
package batch
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import (
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"net/netip"
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"github.com/slackhq/nebula/udp"
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)
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const SendBatchCap = 128
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// DefaultSendBatchArenaCap is the recommended arena capacity for a
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// standalone SendBatch: 128 slots × (udp.MTU + 32) ≈ 1.1 MiB. The +32 covers
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// the nebula header + AEAD tag tacked onto each plaintext segment.
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const DefaultSendBatchArenaCap = SendBatchCap * (udp.MTU + 32)
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// batchWriter is the minimal subset of udp.Conn needed by SendBatch to flush.
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type batchWriter interface {
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WriteBatch(bufs [][]byte, addrs []netip.AddrPort, outerECNs []byte) error
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}
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// SendBatch accumulates encrypted UDP packets and flushes them via WriteBatch.
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// One SendBatch is owned by each listenIn goroutine; no locking is needed.
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// Slot bytes are borrowed from the injected Arena and remain valid until
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// Flush, which Resets the arena.
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type SendBatch struct {
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out batchWriter
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bufs [][]byte
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dsts []netip.AddrPort
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ecns []byte
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arena *Arena
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}
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// NewSendBatch makes a SendBatch with batchCap slots backed by arena.
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func NewSendBatch(out batchWriter, batchCap int, arena *Arena) *SendBatch {
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return &SendBatch{
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out: out,
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bufs: make([][]byte, 0, batchCap),
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dsts: make([]netip.AddrPort, 0, batchCap),
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ecns: make([]byte, 0, batchCap),
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arena: arena,
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}
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}
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func (b *SendBatch) Reserve(sz int) []byte {
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return b.arena.Reserve(sz)
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}
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func (b *SendBatch) Commit(pkt []byte, dst netip.AddrPort, outerECN byte) {
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b.bufs = append(b.bufs, pkt)
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b.dsts = append(b.dsts, dst)
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b.ecns = append(b.ecns, outerECN)
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}
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func (b *SendBatch) Flush() error {
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var err error
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if len(b.bufs) > 0 {
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err = b.out.WriteBatch(b.bufs, b.dsts, b.ecns)
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}
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clear(b.bufs)
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b.bufs = b.bufs[:0]
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b.dsts = b.dsts[:0]
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b.ecns = b.ecns[:0]
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b.arena.Reset()
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return err
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}
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