tc full packet test

tools/ebpf/prepend_capture_header.c

@@ -0,0 +1,41 @@
+#include <linux/bpf.h>
+#include <linux/pkt_cls.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+
+#define CAPTURE_MAGIC 0x4d544350
+#define CAPTURE_VERSION 1
+
+struct capture_header {
+  __be32 magic;
+  __u8 version;
+  __u8 flags;
+  __be16 header_len;
+  __be32 skb_mark;
+  __be32 aux_value;
+} __attribute__((packed));
+
+SEC("classifier")
+int classifier(struct __sk_buff *skb) {
+  struct capture_header hdr = {
+    .magic = bpf_htonl(CAPTURE_MAGIC),
+    .version = CAPTURE_VERSION,
+    .flags = 0,
+    .header_len = bpf_htons(sizeof(struct capture_header)),
+    .skb_mark = bpf_htonl(skb->mark),
+    .aux_value = 0,
+  };
+
+  if (!skb->mark) {
+    return TC_ACT_OK;
+  }
+  if (bpf_skb_adjust_room(skb, sizeof(hdr), BPF_ADJ_ROOM_MAC, 0)) {
+    return TC_ACT_OK;
+  }
+  if (bpf_skb_store_bytes(skb, 0, &hdr, sizeof(hdr), 0)) {
+    return TC_ACT_OK;
+  }
+  return TC_ACT_OK;
+}
+
+char LICENSE[] SEC("license") = "GPL";