whatcanGOwrong

go/pkg/mod/github.com/cilium/ebpf@v0.11.0/features/misc.go

@@ -0,0 +1,79 @@
+package features
+
+import (
+	"github.com/cilium/ebpf"
+	"github.com/cilium/ebpf/asm"
+	"github.com/cilium/ebpf/internal"
+)
+
+// HaveLargeInstructions probes the running kernel if more than 4096 instructions
+// per program are supported.
+//
+// Upstream commit c04c0d2b968a ("bpf: increase complexity limit and maximum program size").
+//
+// See the package documentation for the meaning of the error return value.
+var HaveLargeInstructions = internal.NewFeatureTest(">4096 instructions", "5.2", func() error {
+	const maxInsns = 4096
+
+	insns := make(asm.Instructions, maxInsns, maxInsns+1)
+	for i := range insns {
+		insns[i] = asm.Mov.Imm(asm.R0, 1)
+	}
+	insns = append(insns, asm.Return())
+
+	return probeProgram(&ebpf.ProgramSpec{
+		Type:         ebpf.SocketFilter,
+		Instructions: insns,
+	})
+})
+
+// HaveBoundedLoops probes the running kernel if bounded loops are supported.
+//
+// Upstream commit 2589726d12a1 ("bpf: introduce bounded loops").
+//
+// See the package documentation for the meaning of the error return value.
+var HaveBoundedLoops = internal.NewFeatureTest("bounded loops", "5.3", func() error {
+	return probeProgram(&ebpf.ProgramSpec{
+		Type: ebpf.SocketFilter,
+		Instructions: asm.Instructions{
+			asm.Mov.Imm(asm.R0, 10),
+			asm.Sub.Imm(asm.R0, 1).WithSymbol("loop"),
+			asm.JNE.Imm(asm.R0, 0, "loop"),
+			asm.Return(),
+		},
+	})
+})
+
+// HaveV2ISA probes the running kernel if instructions of the v2 ISA are supported.
+//
+// Upstream commit 92b31a9af73b ("bpf: add BPF_J{LT,LE,SLT,SLE} instructions").
+//
+// See the package documentation for the meaning of the error return value.
+var HaveV2ISA = internal.NewFeatureTest("v2 ISA", "4.14", func() error {
+	return probeProgram(&ebpf.ProgramSpec{
+		Type: ebpf.SocketFilter,
+		Instructions: asm.Instructions{
+			asm.Mov.Imm(asm.R0, 0),
+			asm.JLT.Imm(asm.R0, 0, "exit"),
+			asm.Mov.Imm(asm.R0, 1),
+			asm.Return().WithSymbol("exit"),
+		},
+	})
+})
+
+// HaveV3ISA probes the running kernel if instructions of the v3 ISA are supported.
+//
+// Upstream commit 092ed0968bb6 ("bpf: verifier support JMP32").
+//
+// See the package documentation for the meaning of the error return value.
+var HaveV3ISA = internal.NewFeatureTest("v3 ISA", "5.1", func() error {
+	return probeProgram(&ebpf.ProgramSpec{
+		Type: ebpf.SocketFilter,
+		Instructions: asm.Instructions{
+			asm.Mov.Imm(asm.R0, 0),
+			asm.JLT.Imm32(asm.R0, 0, "exit"),
+			asm.Mov.Imm(asm.R0, 1),
+			asm.Return().WithSymbol("exit"),
+		},
+	})
+})