fix bpf map update

Signed-off-by: Ric Li <[email protected]>
OpenVisualCloud · Jan 29, 2024 · 462985b · 462985b
1 parent e34f00b
commit 462985b
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Showing 3 changed files with 58 additions and 27 deletions.
diff --git a/manager/README.md b/manager/README.md
@@ -30,14 +30,14 @@ sudo ./build/MtlManager
 
 This command will start the MTL Manager with root privileges, which are necessary for the advanced eBPF and network configurations and management tasks it performs.
 
-## Run with our XDP program
+## Run with another XDP program
 
-We have a modified version of the original AF_XDP eBPF program which allows user to add or remove udp dest port in the eBPF program to act as a packet filter, please see [ebpf tool](../tools/ebpf) for how to build it.
+We have a modified version of the original AF_XDP eBPF program which allows user to add or remove udp dest port in the eBPF program to act as a packet filter, this is built in the manager.
 
-To run the MTL Manager with our XDP program, execute:
+To run the MTL Manager with any other AF_XDP eBPF program, execute:
 
 ```bash
-sudo MTL_XDP_PROG_PATH=/path/to/Media-Transport-Library/tools/ebpf/xsk.xdp.o ./build/MtlManager
+sudo MTL_XDP_PROG_PATH=/path/to/xsk.xdp.o ./build/MtlManager
 ```
 
 ## Run in a Docker container
@@ -57,7 +57,6 @@ docker run -d \
   --privileged --net=host \
   -v /var/run/imtl:/var/run/imtl \
   -v /sys/fs/bpf:/sys/fs/bpf \
-  -v "$(pwd)"/../tools/ebpf/xsk.xdp.o:/tmp/imtl/xdp_prog.o \
   mtl-manager:latest
 ```
 

diff --git a/manager/manager.xdp.c b/manager/manager.xdp.c
@@ -68,3 +68,8 @@ int xsk_def_prog(struct xdp_md* ctx) {
 
   return bpf_redirect_map(&xsks_map, ctx->rx_queue_index, XDP_PASS);
 }
+
+#define XDP_METADATA_SECTION "xdp_metadata"
+#define XSK_PROG_VERSION 1
+
+__uint(xsk_prog_version, XSK_PROG_VERSION) SEC(XDP_METADATA_SECTION);
diff --git a/manager/mtl_interface.hpp b/manager/mtl_interface.hpp
@@ -27,6 +27,8 @@ class mtl_interface {
   const int ifindex;
   struct xdp_program* xdp_prog;
   int xsks_map_fd;
+  int udp4_dp_filter_fd;
+  enum xdp_attach_mode xdp_mode;
 
  private:
   void log(const log_level& level, const std::string& message) const {
@@ -47,7 +49,11 @@ class mtl_interface {
 };
 
 mtl_interface::mtl_interface(int ifindex)
-    : ifindex(ifindex), xdp_prog(nullptr), xsks_map_fd(-1) {
+    : ifindex(ifindex),
+      xdp_prog(nullptr),
+      xsks_map_fd(-1),
+      udp4_dp_filter_fd(-1),
+      xdp_mode(XDP_MODE_UNSPEC) {
 #ifdef MTL_HAS_XDP_BACKEND
   if (load_xdp() < 0) throw std::runtime_error("Failed to load XDP program.");
 #endif
@@ -71,15 +77,13 @@ int mtl_interface::update_udp_dp_filter(uint16_t dst_port, bool add) {
     return -1;
   }
 
-  int map_fd = bpf_map__fd(
-      bpf_object__find_map_by_name(xdp_program__bpf_obj(xdp_prog), "udp4_dp_filter"));
-  if (map_fd < 0) {
-    log(log_level::WARNING, "Failed to get udp4_dp_filter map fd");
+  if (udp4_dp_filter_fd < 0) {
+    log(log_level::WARNING, "No valid udp4_dp_filter map fd");
     return -1;
   }
 
   int value = add ? 1 : 0;
-  if (bpf_map_update_elem(map_fd, &dst_port, &value, BPF_ANY) < 0) {
+  if (bpf_map_update_elem(udp4_dp_filter_fd, &dst_port, &value, BPF_ANY) < 0) {
     log(log_level::WARNING, "Failed to update udp4_dp_filter map");
     return -1;
   }
@@ -139,29 +143,38 @@ int mtl_interface::clear_flow_rules() {
 #ifdef MTL_HAS_XDP_BACKEND
 int mtl_interface::load_xdp() {
   /* get customized xdp prog path from env */
-  std::string xdp_prog_path = getenv("MTL_XDP_PROG_PATH");
-
-  if (!std::filesystem::is_regular_file(xdp_prog_path)) {
-    log(log_level::WARNING,
-        "Fallback to use built-in prog for " + xdp_prog_path + " is not valid.");
-  } else {
-    xdp_prog = xdp_program__open_file(xdp_prog_path.c_str(), NULL, NULL);
-    if (libxdp_get_error(xdp_prog)) {
-      log(log_level::WARNING, "Fallback to use built-in prog prog for " + xdp_prog_path +
-                                  " cannot be loaded.");
-      xdp_prog = nullptr;
+  std::string xdp_prog_path;
+  char* xdp_prog_path_env = getenv("MTL_XDP_PROG_PATH");
+  if (xdp_prog_path_env != nullptr) {
+    xdp_prog_path = xdp_prog_path_env;
+    if (!std::filesystem::is_regular_file(xdp_prog_path)) {
+      log(log_level::WARNING,
+          "Fallback to use built-in prog for " + xdp_prog_path + " is not valid.");
+    } else {
+      xdp_prog = xdp_program__open_file(xdp_prog_path.c_str(), NULL, NULL);
+      if (libxdp_get_error(xdp_prog)) {
+        log(log_level::WARNING, "Fallback to use built-in prog prog for " +
+                                    xdp_prog_path + " cannot be loaded.");
+        xdp_prog = nullptr;
+      }
     }
+  } else {
+    xdp_prog_path = "<built-in>";
   }
 
+  struct manager_xdp* skel = NULL;
   if (xdp_prog == nullptr) {
     /* load built-in xdp prog from skeleton */
-    xdp_prog_path = "<built-in>";
-    struct manager_xdp* skel = manager_xdp__open();
+    skel = manager_xdp__open_and_load();
     if (!skel) {
       log(log_level::ERROR, "Failed to open built-in xdp prog skeleton");
       return -1;
     }
-    xdp_prog = xdp_program__from_bpf_obj(skel->obj, "xdp");
+    xdp_prog = xdp_program__from_fd(bpf_program__fd(skel->progs.xsk_def_prog));
+    if (libxdp_get_error(xdp_prog)) {
+      log(log_level::ERROR, "Failed to load built-in xdp prog");
+      return -1;
+    }
   }
 
   if (xdp_program__attach(xdp_prog, ifindex, XDP_MODE_NATIVE, 0) < 0) {
@@ -172,11 +185,24 @@ int mtl_interface::load_xdp() {
       xdp_program__close(xdp_prog);
       return -1;
     }
+    xdp_mode = XDP_MODE_SKB;
+  }
+  xdp_mode = XDP_MODE_NATIVE;
+
+  struct bpf_map* map = skel ? skel->maps.udp4_dp_filter
+                             : bpf_object__find_map_by_name(
+                                   xdp_program__bpf_obj(xdp_prog), "udp4_dp_filter");
+  udp4_dp_filter_fd = bpf_map__fd(map);
+  if (udp4_dp_filter_fd < 0) {
+    log(log_level::ERROR, "Failed to get udp4_dp_filter fd");
+    xdp_program__detach(xdp_prog, ifindex, xdp_mode, 0);
+    xdp_program__close(xdp_prog);
+    return -1;
   }
 
   if (xsk_setup_xdp_prog(ifindex, &xsks_map_fd) < 0 || xsks_map_fd < 0) {
     if (xdp_prog != nullptr) {
-      xdp_program__detach(xdp_prog, ifindex, XDP_MODE_NATIVE, 0);
+      xdp_program__detach(xdp_prog, ifindex, xdp_mode, 0);
       xdp_program__close(xdp_prog);
     }
     /* unload all xdp programs for the interface */
@@ -196,7 +222,7 @@ int mtl_interface::load_xdp() {
 
 void mtl_interface::unload_xdp() {
   if (xdp_prog != nullptr) {
-    xdp_program__detach(xdp_prog, ifindex, XDP_MODE_NATIVE, 0);
+    xdp_program__detach(xdp_prog, ifindex, xdp_mode, 0);
     xdp_program__close(xdp_prog);
     xdp_prog = nullptr;
   } else {
@@ -208,6 +234,7 @@ void mtl_interface::unload_xdp() {
     xdp_multiprog__detach(multiprog);
     xdp_multiprog__close(multiprog);
   }
+
   log(log_level::INFO, "Unloaded xdp prog");
 }
 #endif