Add support for offload/hardware mode.

README.md

@@ -8,6 +8,7 @@ Additionally, if the host's NIC doesn't support XDP-native, the program will att
 The following command line arguments are supported:
 
 * `--config -c` => Location to config file. Default => **/etc/xdpfw/xdpfw.conf**.
+* `--offload -o` => Tries to load the XDP program in hardware/offload mode.
 * `--list -l` => List all filtering rules scanned from config file.
 * `--help -h` => Print help menu for command line options.
 

src/xdpfw_loader.c

@@ -23,10 +23,12 @@
 static char *configFile;
 static int help = 0;
 static int list = 0;
+static int offload = 0;
 
 const struct option opts[] =
 {
     {"config", required_argument, NULL, 'c'},
+    {"offload", no_argument, &offload, 'o'},
     {"list", no_argument, &list, 'l'},
     {"help", no_argument, &help, 'h'},
     {NULL, 0, NULL, 0}
@@ -55,6 +57,11 @@ void parse_command_line(int argc, char *argv[])
 
                 break;
 
+            case 'o':
+                offload = 1;
+
+                break;
+
             case 'l':
                 list = 1;
 
@@ -193,6 +200,16 @@ static int xdp_attach(int ifindex, uint32_t *xdp_flags, int prog_fd)
 {
     int err;
     
+    if (offload)
+    {
+        fprintf(stdout, "Trying to load in offload/hardware mode...\n");
+        
+        *xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_HW_MODE;
+
+        err = bpf_set_link_xdp_fd(ifindex, prog_fd, *xdp_flags);
+    }
+    else
+    {
         err = bpf_set_link_xdp_fd(ifindex, prog_fd, *xdp_flags);
 
         if (err == -EEXIST && !(*xdp_flags & XDP_FLAGS_UPDATE_IF_NOEXIST))
@@ -230,6 +247,7 @@ static int xdp_attach(int ifindex, uint32_t *xdp_flags, int prog_fd)
 
             err = bpf_set_link_xdp_fd(ifindex, prog_fd, *xdp_flags);
         }
+    }
 
     if (err < 0)
     {