104 lines
2.6 KiB
Go
104 lines
2.6 KiB
Go
package link
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import (
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"errors"
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"github.com/cilium/ebpf"
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"github.com/cilium/ebpf/asm"
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"github.com/cilium/ebpf/internal"
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"github.com/cilium/ebpf/internal/sys"
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"github.com/cilium/ebpf/internal/unix"
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)
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// Type is the kind of link.
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type Type = sys.LinkType
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// Valid link types.
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const (
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UnspecifiedType = sys.BPF_LINK_TYPE_UNSPEC
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RawTracepointType = sys.BPF_LINK_TYPE_RAW_TRACEPOINT
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TracingType = sys.BPF_LINK_TYPE_TRACING
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CgroupType = sys.BPF_LINK_TYPE_CGROUP
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IterType = sys.BPF_LINK_TYPE_ITER
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NetNsType = sys.BPF_LINK_TYPE_NETNS
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XDPType = sys.BPF_LINK_TYPE_XDP
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PerfEventType = sys.BPF_LINK_TYPE_PERF_EVENT
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)
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var haveProgAttach = internal.FeatureTest("BPF_PROG_ATTACH", "4.10", func() error {
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prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
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Type: ebpf.CGroupSKB,
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License: "MIT",
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Instructions: asm.Instructions{
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asm.Mov.Imm(asm.R0, 0),
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asm.Return(),
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},
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})
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if err != nil {
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return internal.ErrNotSupported
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}
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// BPF_PROG_ATTACH was introduced at the same time as CGgroupSKB,
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// so being able to load the program is enough to infer that we
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// have the syscall.
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prog.Close()
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return nil
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})
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var haveProgAttachReplace = internal.FeatureTest("BPF_PROG_ATTACH atomic replacement", "5.5", func() error {
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if err := haveProgAttach(); err != nil {
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return err
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}
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prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
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Type: ebpf.CGroupSKB,
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AttachType: ebpf.AttachCGroupInetIngress,
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License: "MIT",
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Instructions: asm.Instructions{
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asm.Mov.Imm(asm.R0, 0),
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asm.Return(),
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},
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})
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if err != nil {
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return internal.ErrNotSupported
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}
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defer prog.Close()
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// We know that we have BPF_PROG_ATTACH since we can load CGroupSKB programs.
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// If passing BPF_F_REPLACE gives us EINVAL we know that the feature isn't
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// present.
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attr := sys.ProgAttachAttr{
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// We rely on this being checked after attachFlags.
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TargetFd: ^uint32(0),
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AttachBpfFd: uint32(prog.FD()),
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AttachType: uint32(ebpf.AttachCGroupInetIngress),
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AttachFlags: uint32(flagReplace),
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}
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err = sys.ProgAttach(&attr)
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if errors.Is(err, unix.EINVAL) {
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return internal.ErrNotSupported
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}
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if errors.Is(err, unix.EBADF) {
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return nil
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}
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return err
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})
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var haveBPFLink = internal.FeatureTest("bpf_link", "5.7", func() error {
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attr := sys.LinkCreateAttr{
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// This is a hopefully invalid file descriptor, which triggers EBADF.
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TargetFd: ^uint32(0),
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ProgFd: ^uint32(0),
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AttachType: sys.AttachType(ebpf.AttachCGroupInetIngress),
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}
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_, err := sys.LinkCreate(&attr)
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if errors.Is(err, unix.EINVAL) {
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return internal.ErrNotSupported
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}
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if errors.Is(err, unix.EBADF) {
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return nil
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}
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return err
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})
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