Add vagrant VM support and XDP_USE_NEED_WAKEUP for advanced03

.gitignore

@@ -66,3 +66,6 @@ trace_load_and_stats
 trace_load_and_stats
 trace_read
 xdp_sample_pkts_user
+
+# Vagrant directory
+.vagrant/

advanced03-AF_XDP/af_xdp_kern.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 
 #include <linux/bpf.h>
+#include <linux/version.h>
 
 #include "bpf_helpers.h"
 
@@ -18,6 +19,17 @@ struct bpf_map_def SEC("maps") xdp_stats_map = {
 	.max_entries = 64,
 };
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,3,0)
+
+/* Kernel version before 5.3 needed an additional map */
+struct bpf_map_def SEC("maps") qidconf_map = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.max_entries = 64,
+};
+#endif
+
 SEC("xdp_sock")
 int xdp_sock_prog(struct xdp_md *ctx)
 {

advanced03-AF_XDP/af_xdp_user.c

@@ -14,6 +14,7 @@
 #include <unistd.h>
 
 #include <sys/resource.h>
+#include <sys/utsname.h>
 
 #include <bpf/bpf.h>
 #include <bpf/xsk.h>
@@ -30,6 +31,9 @@
 #include "../common/common_user_bpf_xdp.h"
 #include "../common/common_libbpf.h"
 
+#ifdef XDP_USE_NEED_WAKEUP
+#define HAS_XDP_NEED_WAKEUP 1
+#endif
 
 #define NUM_FRAMES         4096
 #define FRAME_SIZE         XSK_UMEM__DEFAULT_FRAME_SIZE
@@ -186,6 +190,9 @@ static struct xsk_socket_info *xsk_configure_socket(struct config *cfg,
 	xsk_cfg.libbpf_flags = 0;
 	xsk_cfg.xdp_flags = cfg->xdp_flags;
 	xsk_cfg.bind_flags = cfg->xsk_bind_flags;
+#ifdef HAS_XDP_NEED_WAKEUP
+	xsk_cfg.bind_flags |= XDP_USE_NEED_WAKEUP;
+#endif
 	ret = xsk_socket__create(&xsk_info->xsk, cfg->ifname,
 				 cfg->xsk_if_queue, umem->umem, &xsk_info->rx,
 				 &xsk_info->tx, &xsk_cfg);
@@ -234,7 +241,11 @@ static void complete_tx(struct xsk_socket_info *xsk)
 	if (!xsk->outstanding_tx)
 		return;
 
-	sendto(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL, 0);
+#ifdef HAVE_XDP_NEED_WAKEUP
+	if (xsk_ring_prod__needs_wakeup(&xsk->tx))
+#endif
+		sendto(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT,
+		       NULL, 0);
 
 
 	/* Collect/free completed TX buffers */
@@ -343,8 +354,19 @@ static void handle_receive_packets(struct xsk_socket_info *xsk)
 	int ret;
 
 	rcvd = xsk_ring_cons__peek(&xsk->rx, RX_BATCH_SIZE, &idx_rx);
-	if (!rcvd)
+	if (!rcvd) {
+#ifdef HAS_XDP_NEED_WAKEUP
+		if (xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
+			struct pollfd fds[2];
+
+			memset(fds, 0, sizeof(fds));
+			fds[0].fd = xsk_socket__fd(xsk->xsk);
+			fds[0].events = POLLIN;
+			poll(fds, 1, 0);
+		}
+#endif
 		return;
+	}
 
 	/* Stuff the ring with as much frames as possible */
 	stock_frames = xsk_prod_nb_free(&xsk->umem->fq,
@@ -513,6 +535,29 @@ int main(int argc, char **argv)
 	struct xsk_socket_info *xsk_socket;
 	struct bpf_object *bpf_obj = NULL;
 	pthread_t stats_poll_thread;
+	struct utsname uname_info;
+	unsigned int major, minor, revision;
+
+	/* Some basic version checking for AF_XDP */
+	if (uname(&uname_info) == -1) {
+		fprintf(stderr, "ERROR: failed calling uname(): %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	if (sscanf(uname_info.release, "%u.%u.%u-",
+		   &major, &minor, &revision) != 3) {
+		fprintf(stderr, "ERROR: failed to extract Kernel version\n");
+		exit(EXIT_FAILURE);
+	}
+	if (major < 5 || (major == 5 && minor < 2)) {
+		printf("WARNING: For AF_XDP you need at least an upstream "
+		       "kernel of 5.2!\n");
+	}
+	if (major == 5 && minor == 2) {
+		printf("WARNING: Although AF_XDP is supported in upstream "
+		       "kernel 5.2, due to known libbpf issues it's "
+		       "recommended to use at least version 5.3!\n");
+	}
 
 	/* Global shutdown handler */
 	signal(SIGINT, exit_application);
@@ -581,7 +626,8 @@ int main(int argc, char **argv)
 	/* Open and configure the AF_XDP (xsk) socket */
 	xsk_socket = xsk_configure_socket(&cfg, umem);
 	if (xsk_socket == NULL) {
-		fprintf(stderr, "ERROR: Can't setup AF_XDP socket \"%s\"\n",
+		fprintf(stderr, "ERROR: Can't setup AF_XDP socket \"%s\"\n"
+			"Make sure Kernel is build with CONFIG_XDP_SOCKETS=y\n",
 			strerror(errno));
 		exit(EXIT_FAILURE);
 	}

vagrant/README.org

@@ -0,0 +1,77 @@
+# -*- fill-column: 76; -*-
+#+TITLE: Vagrant image for xdp-tutorial with latest bpf-next kernel
+#+OPTIONS: ^:nil
+
+This Vagrant configuration can be used to test the xdp-tutorial using a
+virtual machine based on Fedora29 with the latest bpf-next kernel.
+
+* Configure Vagrant
+This example uses the libvirt back-end, which needs to be installed:
+
+#+begin_example sh
+vagrant plugin install vagrant-libvirt
+#+end_example
+
+In addition, we also need the /reload/ plugin to reboot the machine:
+
+#+begin_example sh
+vagrant plugin install vagrant-reload
+#+end_example
+
+
+* Configure the virtual machine
+The more cores and memory you will assign to the VM the faster it will build
+the kernel. Please modify the Valgrantfile to change the default 8 cores and
+4G of memory:
+
+#+begin_example ruby
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.cpus = 8
+    libvirt.memory = 4096
+    libvirt.storage :file, :size => '50G', :bus => 'scsi'
+  end
+#+end_example
+
+
+* Start the Vagrant vm
+To start the virtual machine you need to execute the below from the vagrant
+directory:
+
+#+begin_example sh
+$ vagrant up
+Bringing machine 'default' up with 'libvirt' provider...
+==> default: Checking if box 'generic/fedora29' version '1.9.24' is up to date...
+==> default: Creating image (snapshot of base box volume).
+==> default: Creating domain with the following settings...
+==> default:  -- Name:              vagrant_default
+==> default:  -- Domain type:       kvm
+==> default:  -- Cpus:              8
+==> default:  -- Feature:           acpi
+...
+...
+    default:     -D __BPF_TRACING__ \
+    default:     -I../libbpf/src//root/usr/include/ -g -I/usr/include/x86_64-linux-gnu -I../headers/ \
+    default:     -Wall \
+    default:     -Wno-unused-value \
+    default:     -Wno-pointer-sign \
+    default:     -Wno-compare-distinct-pointer-types \
+    default:     -Werror \
+    default:     -O2 -emit-llvm -c -g -o af_xdp_kern.ll af_xdp_kern.c
+    default: llc -march=bpf -filetype=obj -o af_xdp_kern.o af_xdp_kern.ll
+    default: make[1]: Leaving directory '/home/vagrant/xdp-tutorial/advanced03-AF_XDP'
+#+end_example
+
+NOTE: The above will take some time as it will build the kernel from scratch.
+
+If the installation completed successfully you can access the VM as follows:
+
+#+begin_example sh
+$ vagrant ssh default
+[vagrant@xdp-tutorial ~]$ ls
+dp-tutorial
+[vagrant@xdp-tutorial ~]$ cd xdp-tutorial/advanced03-AF_XDP/
+[vagrant@xdp-tutorial advanced03-AF_XDP]$
+[vagrant@xdp-tutorial advanced03-AF_XDP]$ ls
+af_xdp_kern.c   af_xdp_kern.o  af_xdp_user.c  README.org
+af_xdp_kern.ll  af_xdp_user    Makefile
+#+end_example

vagrant/Vagrantfile

@@ -0,0 +1,22 @@
+#
+# NOTE: This script requeres the reload pluging, install it as follows:
+#         vagrant plugin install vagrant-reload
+#
+
+Vagrant.configure("2") do |config|
+
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.cpus = 8
+    libvirt.memory = 4096
+    libvirt.storage :file, :size => '50G', :bus => 'scsi'
+    # libvirt.storage_pool_path = '/home/user/.local/share/libvirt/images'
+  end
+
+  config.vm.box = "generic/fedora29"
+  config.vm.hostname = "xdp-tutorial"
+
+  config.vm.provision :shell, path: "bootstrap.sh"
+  config.vm.provision :reload
+  config.vm.provision :shell, privileged: false, path: "bootstrap_post_kernel.sh"
+
+end

vagrant/bootstrap.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+
+#
+# Install required packages
+#
+dnf install -y \
+    bc \
+    bpftool \
+    clang \
+    elfutils-libelf-devel \
+    emacs-nox \
+    fedora-packager \
+    fedpkg \
+    flex bison \
+    kernel-headers \
+    libpcap-devel \
+    llvm \
+    ncurses-devel \
+    openssl-devel \
+    perf \
+    pesign \
+    rpmdevtools
+
+#
+# Initialize the extra disk needed to build the kernel
+#
+if ! grep -q $(blkid /dev/sdb1 -o value -s UUID) /etc/fstab
+then
+    parted /dev/sdb mklabel gpt
+    parted /dev/sdb mkpart primary 0% 100%
+    mkfs.xfs /dev/sdb1
+    mkdir /data
+    echo "UUID=$(blkid /dev/sdb1 -o value -s UUID) /data                   xfs     defaults        0 0" >> /etc/fstab
+    mount /data
+fi
+
+#
+# Build the latest bpf-next kernel
+#
+cd /data
+git clone https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git linux_kernel
+# This was successfully tested with commit bdb15a29cc28f8155e20f7fb58b60ffc452f2d1b
+cd linux_kernel
+cp /boot/config-$(uname -r) .config
+make olddefconfig
+make -j $(nproc) bzImage
+make -j $(nproc) modules
+make modules_install
+make headers_install
+make install
+
+#
+# Boot the new kernel, and make sure IPv6 is enabled
+#
+grubby --set-default-index=1
+sed -i 's/net.ipv6.conf.all.disable_ipv6 = 1/net.ipv6.conf.all.disable_ipv6 = 0/g' /etc/sysctl.conf

vagrant/bootstrap_post_kernel.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+#
+# Clone and build the tutorial
+#
+git clone --recurse-submodules https://github.com/xdp-project/xdp-tutorial.git
+# This was successfully tested with commit 94471eed572a733a71b096975b3cb72509113e6f
+cd xdp-tutorial
+make