Re: [PATCH bpf-next v4 0/6] XDP metadata support for tun driver

[Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de>]

Am 28.02.25 um 06:43 schrieb Lei Yang:
> Hi Marcus
> 
> Since your patches are about the virtual network, I'd like to test it,
> but it conflicts (Please review the attachment to review more details)
> when I apply it to the master branch.
> My test based on this commit:
> commit 1e15510b71c99c6e49134d756df91069f7d18141 (origin/master, origin/HEAD)
> Merge: f09d694cf799 54e1b4becf5e
> Author: Linus Torvalds <torvalds@linux-foundation.org>
> Date:   Thu Feb 27 09:32:42 2025 -0800
> 
>      Merge tag 'net-6.14-rc5' of
> git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
> 
>      Pull networking fixes from Jakub Kicinski:
>       "Including fixes from bluetooth.
> 

Hi,

thank you for including it in your tests.

The mentioned commit is not yet in bpf-next, but I rebased my patch on
latest mainline and attached the updated patch for the conflicting
commit.

The conflict was just about a section that was removed right below
my added line in network_helpers.h, so no functional change.

---

 From c7182e5a4d21696b9e8cd25f92e64e28129e2c6e Mon Sep 17 00:00:00 2001
From: Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de>
Date: Thu, 13 Feb 2025 16:28:19 +0000
Subject: [PATCH] selftests/bpf: move open_tuntap to network helpers

To test the XDP metadata functionality of the tun driver, it's necessary
to create a new tap device first. A helper function for this already
exists in lwt_helpers.h. Move it to the common network helpers header,
so it can be reused in other tests.

Signed-off-by: Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
  tools/testing/selftests/bpf/network_helpers.c | 28 ++++++++++++++++++
  tools/testing/selftests/bpf/network_helpers.h |  3 ++
  .../selftests/bpf/prog_tests/lwt_helpers.h    | 29 -------------------
  3 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 80844a5fb1fe..fcee2c4a637a 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -548,6 +548,34 @@ void close_netns(struct nstoken *token)
  	free(token);
  }
  
+int open_tuntap(const char *dev_name, bool need_mac)
+{
+	int err = 0;
+	struct ifreq ifr;
+	int fd = open("/dev/net/tun", O_RDWR);
+
+	if (!ASSERT_GT(fd, 0, "open(/dev/net/tun)"))
+		return -1;
+
+	ifr.ifr_flags = IFF_NO_PI | (need_mac ? IFF_TAP : IFF_TUN);
+	strncpy(ifr.ifr_name, dev_name, IFNAMSIZ - 1);
+	ifr.ifr_name[IFNAMSIZ - 1] = '\0';
+
+	err = ioctl(fd, TUNSETIFF, &ifr);
+	if (!ASSERT_OK(err, "ioctl(TUNSETIFF)")) {
+		close(fd);
+		return -1;
+	}
+
+	err = fcntl(fd, F_SETFL, O_NONBLOCK);
+	if (!ASSERT_OK(err, "fcntl(O_NONBLOCK)")) {
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
+
  int get_socket_local_port(int sock_fd)
  {
  	struct sockaddr_storage addr;
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index ebec8a8d6f81..175dd547849f 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -8,6 +8,7 @@
  typedef __u16 __sum16;
  #include <linux/if_ether.h>
  #include <linux/if_packet.h>
+#include <linux/if_tun.h>
  #include <linux/ip.h>
  #include <linux/ipv6.h>
  #include <linux/ethtool.h>
@@ -98,6 +99,8 @@ int send_recv_data(int lfd, int fd, uint32_t total_bytes);
  int make_netns(const char *name);
  int remove_netns(const char *name);
  
+int open_tuntap(const char *dev_name, bool need_mac);
+
  static __u16 csum_fold(__u32 csum)
  {
  	csum = (csum & 0xffff) + (csum >> 16);
diff --git a/tools/testing/selftests/bpf/prog_tests/lwt_helpers.h b/tools/testing/selftests/bpf/prog_tests/lwt_helpers.h
index fb1eb8c67361..ccec0fcdabc1 100644
--- a/tools/testing/selftests/bpf/prog_tests/lwt_helpers.h
+++ b/tools/testing/selftests/bpf/prog_tests/lwt_helpers.h
@@ -5,7 +5,6 @@
  
  #include <time.h>
  #include <net/if.h>
-#include <linux/if_tun.h>
  #include <linux/icmp.h>
  
  #include "test_progs.h"
@@ -37,34 +36,6 @@ static inline int netns_delete(void)
  	return system("ip netns del " NETNS ">/dev/null 2>&1");
  }
  
-static int open_tuntap(const char *dev_name, bool need_mac)
-{
-	int err = 0;
-	struct ifreq ifr;
-	int fd = open("/dev/net/tun", O_RDWR);
-
-	if (!ASSERT_GT(fd, 0, "open(/dev/net/tun)"))
-		return -1;
-
-	ifr.ifr_flags = IFF_NO_PI | (need_mac ? IFF_TAP : IFF_TUN);
-	strncpy(ifr.ifr_name, dev_name, IFNAMSIZ - 1);
-	ifr.ifr_name[IFNAMSIZ - 1] = '\0';
-
-	err = ioctl(fd, TUNSETIFF, &ifr);
-	if (!ASSERT_OK(err, "ioctl(TUNSETIFF)")) {
-		close(fd);
-		return -1;
-	}
-
-	err = fcntl(fd, F_SETFL, O_NONBLOCK);
-	if (!ASSERT_OK(err, "fcntl(O_NONBLOCK)")) {
-		close(fd);
-		return -1;
-	}
-
-	return fd;
-}
-
  #define ICMP_PAYLOAD_SIZE     100
  
  /* Match an ICMP packet with payload len ICMP_PAYLOAD_SIZE */
-- 
2.43.0