[PATCH v2 1/4] net: fix VLAN insert doc comment for shared-mbuf error code

[PATCH v2 1/4] net: fix VLAN insert doc comment for shared-mbuf error code

[William Bland]

The implementation returns -EINVAL when the mbuf is shared or
indirect, but the doc comment inaccurately stated -EPERM.

Fixes: c974021a5949 ("ether: add soft vlan encap/decap")
Cc: stable@dpdk.org

Signed-off-by: William Bland <blandwwa@gmail.com>
---
 lib/net/rte_ether.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/net/rte_ether.h b/lib/net/rte_ether.h
index c9a0b536c3..cb10d8fb06 100644
--- a/lib/net/rte_ether.h
+++ b/lib/net/rte_ether.h
@@ -387,7 +387,8 @@ static inline int rte_vlan_strip(struct rte_mbuf *m)
  *   The packet mbuf.
  * @return
  *   - 0: On success
- *   -EPERM: mbuf is shared overwriting would be unsafe
+ *   -EINVAL: overwriting would be unsafe because mbuf is shared or
+ *            indirect, or mbuf's first segment is too short
  *   -ENOSPC: not enough headroom in mbuf
  */
 static inline int rte_vlan_insert(struct rte_mbuf **m)
-- 
2.43.0

[PATCH v2 2/4] net/af_packet: make Rx VLAN stripped flag handling explicit

[William Bland]

Rx VLAN handling set RTE_MBUF_F_RX_VLAN_STRIPPED unconditionally,
relying on rte_vlan_insert() to clear it again. This produced correct
flags, but in a way that was not readily apparent from the driver.

Make the flag handling explicit in the driver itself: only set
RTE_MBUF_F_RX_VLAN_STRIPPED when vlan_strip is requested, or when
reinsertion fails. No behavioral change.

Signed-off-by: William Bland <blandwwa@gmail.com>
---
 drivers/net/af_packet/rte_eth_af_packet.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
index b0ff22ea55..d95d045a37 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -223,10 +223,14 @@ eth_af_packet_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 		/* check for vlan info */
 		if (ppd->tp_status & TP_STATUS_VLAN_VALID) {
 			mbuf->vlan_tci = ppd->tp_vlan_tci;
-			mbuf->ol_flags |= (RTE_MBUF_F_RX_VLAN | RTE_MBUF_F_RX_VLAN_STRIPPED);
+			mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN;
 
-			if (!pkt_q->vlan_strip && rte_vlan_insert(&mbuf))
+			if (pkt_q->vlan_strip) {
+				mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN_STRIPPED;
+			} else if (rte_vlan_insert(&mbuf) != 0) {
 				PMD_LOG(ERR, "Failed to reinsert VLAN tag");
+				mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN_STRIPPED;
+			}
 		}
 
 		/* add kernel provided timestamp when offloading is enabled */
-- 
2.43.0

[PATCH v2 3/4] net: add VLAN insert function with a TPID argument

[William Bland]

rte_vlan_insert() hardcodes EtherType 0x8100 (802.1Q). This is wrong
when reinserting a stripped tag whose original TPID was 0x88a8 (802.1ad
QinQ).

Add rte_vlan_insert_tpid() which takes an explicit tpid parameter, and
rewrite rte_vlan_insert() as a wrapper that passes RTE_ETHER_TYPE_VLAN.

Signed-off-by: William Bland <blandwwa@gmail.com>
---
 app/test/meson.build                   |   2 +-
 app/test/test_net_ether.c              | 149 +++++++++++++++++++++++--
 doc/guides/rel_notes/release_26_11.rst |   7 ++
 lib/net/rte_ether.h                    |  61 +++++++---
 4 files changed, 193 insertions(+), 26 deletions(-)

diff --git a/app/test/meson.build b/app/test/meson.build
index 51abeeb732..e927d4306a 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -134,7 +134,7 @@ source_file_deps = {
     'test_meter.c': ['meter'],
     'test_metrics.c': ['metrics'],
     'test_mp_secondary.c': ['hash'],
-    'test_net_ether.c': ['net'],
+    'test_net_ether.c': ['net', 'mbuf'],
     'test_net_ip6.c': ['net'],
     'test_pcapng.c': ['net_null', 'net', 'ethdev', 'pcapng', 'bus_vdev'],
     'test_pdcp.c': ['eventdev', 'pdcp', 'net', 'timer', 'security'],
diff --git a/app/test/test_net_ether.c b/app/test/test_net_ether.c
index ec11224171..a1ead2eba8 100644
--- a/app/test/test_net_ether.c
+++ b/app/test/test_net_ether.c
@@ -3,6 +3,8 @@
  */
 
 #include <rte_ether.h>
+#include <rte_mbuf.h>
+#include <rte_mempool.h>
 
 #include <rte_test.h>
 #include "test.h"
@@ -14,6 +16,8 @@ static const struct rte_ether_addr bcast_ea = {
 	.addr_bytes = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 };
 
+static struct rte_mempool *net_ether_test_pool;
+
 static int
 test_ether_addr(void)
 {
@@ -144,22 +148,147 @@ test_invalid_addr(void)
 	return 0;
 }
 
+/*
+ * Build a minimal Ethernet frame in an mbuf: Ethernet header with the given
+ * ether_type followed by payload_len bytes of padding.
+ */
+static struct rte_mbuf *
+alloc_frame(struct rte_mempool *mp, uint16_t ether_type, uint16_t payload_len)
+{
+	struct rte_ether_hdr *eh;
+	struct rte_mbuf *m;
+
+	m = rte_pktmbuf_alloc(mp);
+	if (m == NULL)
+		return NULL;
+
+	eh = (struct rte_ether_hdr *)rte_pktmbuf_append(m,
+			sizeof(*eh) + payload_len);
+	if (eh == NULL) {
+		rte_pktmbuf_free(m);
+		return NULL;
+	}
+
+	memset(eh->dst_addr.addr_bytes, 0xff, RTE_ETHER_ADDR_LEN);
+	memset(eh->src_addr.addr_bytes, 0x00, RTE_ETHER_ADDR_LEN);
+	eh->ether_type = rte_cpu_to_be_16(ether_type);
+
+	return m;
+}
+
 static int
-test_net_ether(void)
+test_vlan_insert_8021q(void)
 {
-	if (test_ether_addr())
-		return -1;
+	struct rte_ether_hdr *eh;
+	struct rte_vlan_hdr *vh;
+	struct rte_mbuf *m;
+	int ret;
 
-	if (test_format_addr())
-		return -1;
+	m = alloc_frame(net_ether_test_pool, RTE_ETHER_TYPE_IPV4, 46);
+	TEST_ASSERT_NOT_NULL(m, "Failed to allocate mbuf");
 
-	if (test_unformat_addr())
-		return -1;
+	m->vlan_tci = 100;
+	m->ol_flags |= RTE_MBUF_F_RX_VLAN | RTE_MBUF_F_RX_VLAN_STRIPPED;
 
-	if (test_invalid_addr())
-		return -1;
+	ret = rte_vlan_insert(&m);
+	TEST_ASSERT_SUCCESS(ret, "rte_vlan_insert failed");
 
-	return 0;
+	eh = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(eh->ether_type), RTE_ETHER_TYPE_VLAN,
+		"Expected 802.1Q TPID 0x%04x, got 0x%04x",
+		RTE_ETHER_TYPE_VLAN, rte_be_to_cpu_16(eh->ether_type));
+
+	vh = (struct rte_vlan_hdr *)(eh + 1);
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(vh->vlan_tci), 100,
+		"Expected VID 100, got %u", rte_be_to_cpu_16(vh->vlan_tci));
+
+	rte_pktmbuf_free(m);
+	return TEST_SUCCESS;
+}
+
+static int
+test_vlan_insert_tpid(void)
+{
+	struct rte_ether_hdr *eh;
+	struct rte_vlan_hdr *vh;
+	struct rte_mbuf *m;
+	int ret;
+
+	m = alloc_frame(net_ether_test_pool, RTE_ETHER_TYPE_VLAN, sizeof(*vh) + 46);
+	TEST_ASSERT_NOT_NULL(m, "Failed to allocate mbuf");
+
+	vh = (struct rte_vlan_hdr *)(rte_pktmbuf_mtod(m, struct rte_ether_hdr *) + 1);
+	vh->vlan_tci = rte_cpu_to_be_16(200);
+	vh->eth_proto = rte_cpu_to_be_16(RTE_ETHER_TYPE_IPV4);
+
+	m->vlan_tci = 50;
+	m->ol_flags |= RTE_MBUF_F_RX_VLAN | RTE_MBUF_F_RX_VLAN_STRIPPED;
+
+	ret = rte_vlan_insert_tpid(&m, RTE_ETHER_TYPE_QINQ);
+	TEST_ASSERT_SUCCESS(ret, "rte_vlan_insert_tpid failed");
+
+	eh = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
+
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(eh->ether_type), RTE_ETHER_TYPE_QINQ,
+		"Outer TPID: expected 0x%04x (802.1ad) got 0x%04x",
+		RTE_ETHER_TYPE_QINQ, rte_be_to_cpu_16(eh->ether_type));
+
+	vh = (struct rte_vlan_hdr *)(eh + 1);
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(vh->vlan_tci), 50,
+		"Outer VID: expected 50, got %u",
+		rte_be_to_cpu_16(vh->vlan_tci));
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(vh->eth_proto), RTE_ETHER_TYPE_VLAN,
+		"Outer eth_proto: expected 0x%04x (802.1Q), got 0x%04x",
+		RTE_ETHER_TYPE_VLAN, rte_be_to_cpu_16(vh->eth_proto));
+
+	vh = vh + 1;
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(vh->vlan_tci), 200,
+		"Inner VID: expected 200, got %u",
+		rte_be_to_cpu_16(vh->vlan_tci));
+	TEST_ASSERT_EQUAL(rte_be_to_cpu_16(vh->eth_proto), RTE_ETHER_TYPE_IPV4,
+		"Inner eth_proto: expected 0x%04x (IPv4), got 0x%04x",
+		RTE_ETHER_TYPE_IPV4, rte_be_to_cpu_16(vh->eth_proto));
+
+	rte_pktmbuf_free(m);
+	return TEST_SUCCESS;
+}
+
+static int
+net_ether_testsuite_setup(void)
+{
+	net_ether_test_pool = rte_pktmbuf_pool_create("net_ether_test_pool", 64, 0, 0,
+			RTE_MBUF_DEFAULT_BUF_SIZE, SOCKET_ID_ANY);
+	TEST_ASSERT_NOT_NULL(net_ether_test_pool, "Failed to create mempool");
+
+	return TEST_SUCCESS;
+}
+
+static void
+net_ether_testsuite_teardown(void)
+{
+	rte_mempool_free(net_ether_test_pool);
+	net_ether_test_pool = NULL;
+}
+
+static struct unit_test_suite net_ether_testsuite = {
+	.suite_name = "net_ether autotest",
+	.setup = net_ether_testsuite_setup,
+	.teardown = net_ether_testsuite_teardown,
+	.unit_test_cases = {
+		TEST_CASE(test_ether_addr),
+		TEST_CASE(test_format_addr),
+		TEST_CASE(test_unformat_addr),
+		TEST_CASE(test_invalid_addr),
+		TEST_CASE(test_vlan_insert_8021q),
+		TEST_CASE(test_vlan_insert_tpid),
+		TEST_CASES_END()
+	}
+};
+
+static int
+test_net_ether(void)
+{
+	return unit_test_suite_runner(&net_ether_testsuite);
 }
 
 REGISTER_FAST_TEST(net_ether_autotest, NOHUGE_OK, ASAN_OK, test_net_ether);
diff --git a/doc/guides/rel_notes/release_26_11.rst b/doc/guides/rel_notes/release_26_11.rst
index c8cc86295d..a7481b51ff 100644
--- a/doc/guides/rel_notes/release_26_11.rst
+++ b/doc/guides/rel_notes/release_26_11.rst
@@ -55,6 +55,13 @@ New Features
      Also, make sure to start the actual text at the margin.
      =======================================================
 
+* **Added TPID support to VLAN tag insertion.**
+
+  Added ``rte_vlan_insert_tpid()`` to the net library, allowing the Tag
+  Protocol Identifier (TPID) of an inserted VLAN tag to be specified
+  explicitly, so that 802.1ad (QinQ) outer tags can be reinserted with
+  the correct EtherType.
+
 
 Removed Items
 -------------
diff --git a/lib/net/rte_ether.h b/lib/net/rte_ether.h
index cb10d8fb06..23c4806cc5 100644
--- a/lib/net/rte_ether.h
+++ b/lib/net/rte_ether.h
@@ -378,20 +378,7 @@ static inline int rte_vlan_strip(struct rte_mbuf *m)
 	return 0;
 }
 
-/**
- * Insert VLAN tag into mbuf.
- *
- * Software version of VLAN unstripping
- *
- * @param m
- *   The packet mbuf.
- * @return
- *   - 0: On success
- *   -EINVAL: overwriting would be unsafe because mbuf is shared or
- *            indirect, or mbuf's first segment is too short
- *   -ENOSPC: not enough headroom in mbuf
- */
-static inline int rte_vlan_insert(struct rte_mbuf **m)
+static inline int __rte_vlan_insert(struct rte_mbuf **m, uint16_t tpid)
 {
 	struct rte_ether_hdr *oh, *nh;
 	struct rte_vlan_hdr *vh;
@@ -411,7 +398,7 @@ static inline int rte_vlan_insert(struct rte_mbuf **m)
 		return -ENOSPC;
 
 	memmove(nh, oh, 2 * RTE_ETHER_ADDR_LEN);
-	nh->ether_type = rte_cpu_to_be_16(RTE_ETHER_TYPE_VLAN);
+	nh->ether_type = rte_cpu_to_be_16(tpid);
 
 	vh = (struct rte_vlan_hdr *) (nh + 1);
 	vh->vlan_tci = rte_cpu_to_be_16((*m)->vlan_tci);
@@ -426,6 +413,50 @@ static inline int rte_vlan_insert(struct rte_mbuf **m)
 	return 0;
 }
 
+/**
+ * Insert VLAN tag into mbuf.
+ *
+ * Software version of VLAN unstripping. Always inserts an 802.1Q tag
+ * (TPID 0x8100). Use rte_vlan_insert_tpid() when the original TPID may
+ * differ (e.g. 802.1ad QinQ outer tags).
+ *
+ * @param m
+ *   The packet mbuf.
+ * @return
+ *   - 0: On success
+ *   -EINVAL: overwriting would be unsafe because mbuf is shared or
+ *            indirect, or mbuf's first segment is too short
+ *   -ENOSPC: not enough headroom in mbuf
+ */
+static inline int rte_vlan_insert(struct rte_mbuf **m)
+{
+	return __rte_vlan_insert(m, RTE_ETHER_TYPE_VLAN);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Insert VLAN tag with the given TPID into mbuf.
+ *
+ * Software version of VLAN unstripping.
+ *
+ * @param m
+ *   The packet mbuf.
+ * @param tpid
+ *   Tag Protocol Identifier to insert (host order).
+ * @return
+ *   - 0: On success
+ *   -EINVAL: overwriting would be unsafe because mbuf is shared or
+ *            indirect, or mbuf's first segment is too short
+ *   -ENOSPC: not enough headroom in mbuf
+ */
+__rte_experimental
+static inline int rte_vlan_insert_tpid(struct rte_mbuf **m, uint16_t tpid)
+{
+	return __rte_vlan_insert(m, tpid);
+}
+
 #ifdef __cplusplus
 }
 #endif
-- 
2.43.0

[PATCH v2 4/4] net/af_packet: fix QinQ outer TPID on VLAN reinsertion

[William Bland]

eth_af_packet_rx() called rte_vlan_insert(), which hardcodes EtherType
0x8100 (802.1Q). This was wrong when reinserting a stripped tag whose
original TPID was 0x88a8 (802.1ad QinQ).

Fix by reading the actual TPID from tp_vlan_tpid (struct tpacket2_hdr),
then passing it to rte_vlan_insert_tpid().

This depends on the rte_vlan_insert_tpid() function added by "net: add
VLAN insert function with a TPID argument".

Fixes: 23deeebfcfa8 ("net/af_packet: support 802.1Q VLAN")
Cc: stable@dpdk.org

Signed-off-by: William Bland <blandwwa@gmail.com>
---
 drivers/net/af_packet/rte_eth_af_packet.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
index d95d045a37..e7fbb3c31d 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -222,14 +222,20 @@ eth_af_packet_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 
 		/* check for vlan info */
 		if (ppd->tp_status & TP_STATUS_VLAN_VALID) {
+			uint16_t tpid;
+
 			mbuf->vlan_tci = ppd->tp_vlan_tci;
 			mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN;
 
 			if (pkt_q->vlan_strip) {
 				mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN_STRIPPED;
-			} else if (rte_vlan_insert(&mbuf) != 0) {
-				PMD_LOG(ERR, "Failed to reinsert VLAN tag");
-				mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN_STRIPPED;
+			} else {
+				tpid = (ppd->tp_status & TP_STATUS_VLAN_TPID_VALID) ?
+					ppd->tp_vlan_tpid : RTE_ETHER_TYPE_VLAN;
+				if (rte_vlan_insert_tpid(&mbuf, tpid) != 0) {
+					PMD_LOG(ERR, "Failed to reinsert VLAN tag");
+					mbuf->ol_flags |= RTE_MBUF_F_RX_VLAN_STRIPPED;
+				}
 			}
 		}
 
-- 
2.43.0

Re: [PATCH v2 1/4] net: fix VLAN insert doc comment for shared-mbuf error code

[Stephen Hemminger]

On Wed, 26 Aug 2026 13:38:38 -0400
William Bland <blandwwa@gmail.com> wrote:

> The implementation returns -EINVAL when the mbuf is shared or
> indirect, but the doc comment inaccurately stated -EPERM.
> 
> Fixes: c974021a5949 ("ether: add soft vlan encap/decap")
> Cc: stable@dpdk.org
> 
> Signed-off-by: William Bland <blandwwa@gmail.com>
> ---

Applied to net-next and I fixed the pre-existing error code formatting.
Turns out you need two '-' to get it to be processed as bullet list with negative number.

Re: [PATCH v2 2/4] net/af_packet: make Rx VLAN stripped flag handling explicit

[Stephen Hemminger]

On Wed, 26 Aug 2026 13:38:39 -0400
William Bland <blandwwa@gmail.com> wrote:

> Rx VLAN handling set RTE_MBUF_F_RX_VLAN_STRIPPED unconditionally,
> relying on rte_vlan_insert() to clear it again. This produced correct
> flags, but in a way that was not readily apparent from the driver.
> 
> Make the flag handling explicit in the driver itself: only set
> RTE_MBUF_F_RX_VLAN_STRIPPED when vlan_strip is requested, or when
> reinsertion fails. No behavioral change.
> 
> Signed-off-by: William Bland <blandwwa@gmail.com>
> ---

Applied to next-net.

Re: [PATCH v2 3/4] net: add VLAN insert function with a TPID argument

[Stephen Hemminger]

On Wed, 26 Aug 2026 13:38:40 -0400
William Bland <blandwwa@gmail.com> wrote:

> rte_vlan_insert() hardcodes EtherType 0x8100 (802.1Q). This is wrong
> when reinserting a stripped tag whose original TPID was 0x88a8 (802.1ad
> QinQ).
> 
> Add rte_vlan_insert_tpid() which takes an explicit tpid parameter, and
> rewrite rte_vlan_insert() as a wrapper that passes RTE_ETHER_TYPE_VLAN.
> 
> Signed-off-by: William Bland <blandwwa@gmail.com>
> ---

Applied to next-net.