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From cd670f3a4f12b35e71802b2c2d57430a5fa624e3 Mon Sep 17 00:00:00 2001
From: Ladi Prosek <lprosek@redhat.com>
Date: Mon, 11 Jul 2016 14:17:36 +0200
Subject: [PATCH] Strip 802.1Q VLAN 0 priority tags

RH-Author: Ladi Prosek <lprosek@redhat.com>
Message-id: <1468246656-15560-1-git-send-email-lprosek@redhat.com>
Patchwork-id: 71112
O-Subject: [RHEL7.3 ipxe PATCH] [netdevice] Strip 802.Q VLAN 0 priority tags
Bugzilla: 1316329
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Xiao Wang <jasowang@redhat.com>

iPXE was unable to receive priority tagged packets specified in
the 802.1Q standard and supported by all major networking stacks.

This commit adds a new function net_pull_tags which is called by
all consumers of incoming packets after stripping their link-layer
headers.

Upstream patch:
http://lists.ipxe.org/pipermail/ipxe-devel/2016-July/005099.html

There is a difference between the upstream patch and this patch in the
path prefix of "interface/pxe/pxe_undi.c" because we don't have upstream
commit f468f12b1eca.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 src/arch/i386/interface/pxe/pxe_undi.c |  6 +++++
 src/include/ipxe/netdevice.h           |  2 ++
 src/interface/efi/efi_snp.c            |  7 ++++++
 src/net/netdevice.c                    | 44 ++++++++++++++++++++++++++++++++++
 4 files changed, 59 insertions(+)

diff --git a/src/arch/i386/interface/pxe/pxe_undi.c b/src/arch/i386/interface/pxe/pxe_undi.c
index 2eb6817..2ea1451 100644
--- a/src/arch/i386/interface/pxe/pxe_undi.c
+++ b/src/arch/i386/interface/pxe/pxe_undi.c
@@ -976,6 +976,12 @@ static PXENV_EXIT_t pxenv_undi_isr ( struct s_PXENV_UNDI_ISR *undi_isr ) {
 		}
 		ll_hlen = ( len - iob_len ( iobuf ) );
 
+		/* Strip link-layer-independent headers */
+		if ( ( rc = net_pull_tags ( iobuf, pxe_netdev, &net_proto ) ) != 0 ) {
+			/* Assume unknown net_proto */
+			net_proto = 0;
+		}
+
 		/* Determine network-layer protocol */
 		switch ( net_proto ) {
 		case htons ( ETH_P_IP ):
diff --git a/src/include/ipxe/netdevice.h b/src/include/ipxe/netdevice.h
index a1d207f..cea87f7 100644
--- a/src/include/ipxe/netdevice.h
+++ b/src/include/ipxe/netdevice.h
@@ -719,6 +719,8 @@ extern int net_tx ( struct io_buffer *iobuf, struct net_device *netdev,
 extern int net_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    uint16_t net_proto, const void *ll_dest,
 		    const void *ll_source, unsigned int flags );
+extern int net_pull_tags ( struct io_buffer *iobuf, struct net_device *netdev,
+			   uint16_t *net_proto );
 extern void net_poll ( void );
 extern struct net_device_configurator *
 find_netdev_configurator ( const char *name );
diff --git a/src/interface/efi/efi_snp.c b/src/interface/efi/efi_snp.c
index 4508967..bf5e48e 100644
--- a/src/interface/efi/efi_snp.c
+++ b/src/interface/efi/efi_snp.c
@@ -744,6 +744,13 @@ efi_snp_receive ( EFI_SIMPLE_NETWORK_PROTOCOL *snp,
 		goto out_bad_ll_header;
 	}
 
+	/* Strip link-layer-independent headers */
+	if ( ( rc = net_pull_tags ( iobuf, snpdev->netdev, &iob_net_proto ) ) ) {
+		DBGC ( snpdev, "SNPDEV %p could not parse tags: %s\n",
+		       snpdev, strerror ( rc ) );
+		goto out_bad_ll_header;
+	}
+
 	/* Return link-layer header parameters to caller, if required */
 	if ( ll_header_len )
 		*ll_header_len = ll_protocol->ll_header_len;
diff --git a/src/net/netdevice.c b/src/net/netdevice.c
index 7c40a2a..2d808b6 100644
--- a/src/net/netdevice.c
+++ b/src/net/netdevice.c
@@ -1018,6 +1018,44 @@ int net_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 }
 
 /**
+ * Strip extra link-layer-independent tags from a received packet
+ *
+ * @v iobuf		I/O buffer
+ * @v netdev		Network device
+ * @v net_proto		Network-layer protocol, in network-byte order
+ * @ret rc		Return status code
+ *
+ * This function should be called after stripping link-layer headers but
+ * before inspecting the network-layer protocol.
+ */
+int net_pull_tags ( struct io_buffer *iobuf, struct net_device *netdev,
+		    uint16_t *net_proto ) {
+	struct vlan_header *vlanhdr;
+	uint16_t tag;
+
+	/* Strip 802.1Q VLAN 0 priority tags if present */
+	while ( *net_proto == htons ( ETH_P_8021Q ) ) {
+		if ( iob_len ( iobuf ) < sizeof ( *vlanhdr ) ) {
+			DBG ( "VLAN header too short at %zd bytes (min %zd bytes)\n",
+			      iob_len ( iobuf ), sizeof ( *vlanhdr ) );
+			return -EINVAL;
+		}
+		vlanhdr = ( struct vlan_header * ) iobuf->data;
+		tag = VLAN_TAG ( ntohs ( vlanhdr->tci ) );
+
+		if ( tag == 0 && ! vlan_find ( netdev, tag ) ) {
+			/* VLAN 0, strip and continue */
+			*net_proto = vlanhdr->net_proto;
+			iob_pull ( iobuf, sizeof ( *vlanhdr ) );
+		} else {
+			/* Real VLAN tag, leave it alone */
+			break;
+		}
+	}
+	return 0;
+}
+
+/**
  * Poll the network stack
  *
  * This polls all interfaces for received packets, and processes
@@ -1068,6 +1106,12 @@ void net_poll ( void ) {
 				continue;
 			}
 
+			/* Remove link-layer-independent headers */
+			if ( ( rc = net_pull_tags ( iobuf, netdev, &net_proto ) ) ) {
+				free_iob ( iobuf );
+				continue;
+			}
+
 			/* Hand packet to network layer */
 			if ( ( rc = net_rx ( iob_disown ( iobuf ), netdev,
 					     net_proto, ll_dest,
-- 
1.8.3.1