1 files changed, 70 insertions, 0 deletions
diff --git a/xdp_loader.c b/xdp_loader.c
new file mode 100644
index 0000000..6f620b8
--- /dev/null
+++ b/xdp_loader.c
@@ -0,0 +1,70 @@
+#include <arpa/inet.h>
+#include <errno.h>
+#include <net/if.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include <linux/if_link.h>
+
+int main(int argc, char **argv) {
+  if (argc != 2) {
+    fprintf(stderr, "Usage: %s <iface>\n", argv[0]);
+    return 1;
+  }
+
+  const char *const iface = argv[1];
+
+  int ifindex = if_nametoindex(iface);
+  if (!ifindex) {
+    perror("if_nametoindex");
+    return 1;
+  }
+
+  struct bpf_object *obj;
+  int prog_fd;
+  const char *const xdp_file = "xdp_udp_handler.o";
+
+  obj = bpf_object__open_file(xdp_file, NULL);
+  if (!obj) {
+    fprintf(stderr, "Error opening BPF object file: `%s'\n", xdp_file);
+    return 1;
+  }
+
+  if (bpf_object__load(obj)) {
+    fprintf(stderr, "Error loading BPF object\n");
+    return 1;
+  }
+
+  struct bpf_program *const prog =
+      bpf_object__find_program_by_name(obj, "xdp_udp_handler");
+  if (!prog) {
+    fprintf(stderr, "Couldn't find program\n");
+    return 1;
+  }
+
+  prog_fd = bpf_program__fd(prog);
+  if (prog_fd < 0) {
+    fprintf(stderr, "Invalid program FD\n");
+    return 1;
+  }
+
+  printf("Attaching BPF program in driver (native) mode..\n");
+  if (bpf_xdp_attach(ifindex, prog_fd,
+                     XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_DRV_MODE,
+                     NULL) < 0) {
+    perror("bpf_xdp_attach");
+    printf("Attaching BPF program in kernel mode..\n");
+    if (bpf_xdp_attach(ifindex, prog_fd, XDP_FLAGS_UPDATE_IF_NOEXIST, NULL) <
+        0) {
+      perror("bpf_xdp_attach");
+      return 1;
+    }
+  }
+
+  printf("XDP program loaded\n");
+  return 0;
+}