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[USMON-1319] usm: Add raw tracepoint for netif_receive_skb #32496

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merged 2 commits into from
Dec 26, 2024
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[USMON-1319] usm: Add raw tracepoint for netif_receive_skb #32496

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dce4e9a
usm: Add raw tracepoint implementation for netif_receive_skb
guyarb Dec 24, 2024
36f3e09
usm: Add user mode algorithm to dynamically decide which probe to use
guyarb Dec 24, 2024
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8 changes: 8 additions & 0 deletions pkg/network/ebpf/c/protocols/flush.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,4 +28,12 @@ int tracepoint__net__netif_receive_skb(void *ctx) {
return 0;
}

SEC("raw_tracepoint/net/netif_receive_skb")
int BPF_PROG(raw_tracepoint__net__netif_receive_skb) {
CHECK_BPF_PROGRAM_BYPASSED()
log_debug("raw_tracepoint/net/netif_receive_skb");
flush(ctx);
return 0;
}

#endif
38 changes: 31 additions & 7 deletions pkg/network/usm/ebpf_main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,10 +14,12 @@ import (
"slices"
"unsafe"

manager "github.com/DataDog/ebpf-manager"
"github.com/cilium/ebpf"
"github.com/cilium/ebpf/features"
"github.com/davecgh/go-spew/spew"

manager "github.com/DataDog/ebpf-manager"

ddebpf "github.com/DataDog/datadog-agent/pkg/ebpf"
"github.com/DataDog/datadog-agent/pkg/ebpf/bytecode"
"github.com/DataDog/datadog-agent/pkg/ebpf/prebuilt"
Expand Down Expand Up @@ -67,6 +69,9 @@ const (
sockFDLookup = "kprobe__sockfd_lookup_light"
sockFDLookupRet = "kretprobe__sockfd_lookup_light"

netifReceiveSkbTp = "tracepoint__net__netif_receive_skb"
netifReceiveSkbRawTp = "raw_tracepoint__net__netif_receive_skb"

tcpCloseProbe = "kprobe__tcp_close"

// maxActive configures the maximum number of instances of the
Expand All @@ -90,6 +95,23 @@ type ebpfProgram struct {
}

func newEBPFProgram(c *config.Config, connectionProtocolMap *ebpf.Map) (*ebpfProgram, error) {
netifProbe := manager.Probe{
ProbeIdentificationPair: manager.ProbeIdentificationPair{
EBPFFuncName: netifReceiveSkbTp,
UID: probeUID,
},
}
if features.HaveProgramType(ebpf.RawTracepoint) == nil {
netifProbe = manager.Probe{
ProbeIdentificationPair: manager.ProbeIdentificationPair{
EBPFFuncName: netifReceiveSkbRawTp,
UID: probeUID,
},
TracepointCategory: "net",
TracepointName: "netif_receive_skb",
}
}

mgr := &manager.Manager{
Maps: []*manager.Map{
{Name: protocols.TLSDispatcherProgramsMap},
Expand All @@ -114,12 +136,7 @@ func newEBPFProgram(c *config.Config, connectionProtocolMap *ebpf.Map) (*ebpfPro
UID: probeUID,
},
},
{
ProbeIdentificationPair: manager.ProbeIdentificationPair{
EBPFFuncName: "tracepoint__net__netif_receive_skb",
UID: probeUID,
},
},
&netifProbe,
{
ProbeIdentificationPair: manager.ProbeIdentificationPair{
EBPFFuncName: protocolDispatcherSocketFilterFunction,
Expand Down Expand Up @@ -462,6 +479,13 @@ func (e *ebpfProgram) init(buf bytecode.AssetReader, options manager.Options) er
}
}

// exclude unused netif_receive_skb probe
if features.HaveProgramType(ebpf.RawTracepoint) == nil {
options.ExcludedFunctions = append(options.ExcludedFunctions, netifReceiveSkbTp)
} else {
options.ExcludedFunctions = append(options.ExcludedFunctions, netifReceiveSkbRawTp)
}

err := e.InitWithOptions(buf, &options)
if err != nil {
cleanup()
Expand Down
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