Re: [RFC PATCH v7 06/16] net: dsa: tag_qca: add define for handling mgmt Ethernet packet

Ansuel Smith
2022-01-24T16:16:54Z

On Mon, Jan 24, 2022 at 06:05:37PM +0200, Vladimir Oltean wrote:
> On Sun, Jan 23, 2022 at 02:33:27AM +0100, Ansuel Smith wrote:
> > Add all the required define to prepare support for mgmt read/write in
> > Ethernet packet. Any packet of this type has to be dropped as the only
> > use of these special packet is receive ack for an mgmt write request or
> > receive data for an mgmt read request.
> > A struct is used that emulates the Ethernet header but is used for a
> > different purpose.
> >
> > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> > ---
> > include/linux/dsa/tag_qca.h | 44 +++++++++++++++++++++++++++++++++++++
> > net/dsa/tag_qca.c | 13 ++++++++---
> > 2 files changed, 54 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/dsa/tag_qca.h b/include/linux/dsa/tag_qca.h
> > index c02d2d39ff4a..1a02f695f3a3 100644
> > --- a/include/linux/dsa/tag_qca.h
> > +++ b/include/linux/dsa/tag_qca.h
> > @@ -12,10 +12,54 @@
> > #define QCA_HDR_RECV_FRAME_IS_TAGGED BIT(3)
> > #define QCA_HDR_RECV_SOURCE_PORT GENMASK(2, 0)
> >
> > +/* Packet type for recv */
> > +#define QCA_HDR_RECV_TYPE_NORMAL 0x0
> > +#define QCA_HDR_RECV_TYPE_MIB 0x1
> > +#define QCA_HDR_RECV_TYPE_RW_REG_ACK 0x2
> > +
> > #define QCA_HDR_XMIT_VERSION GENMASK(15, 14)
> > #define QCA_HDR_XMIT_PRIORITY GENMASK(13, 11)
> > #define QCA_HDR_XMIT_CONTROL GENMASK(10, 8)
> > #define QCA_HDR_XMIT_FROM_CPU BIT(7)
> > #define QCA_HDR_XMIT_DP_BIT GENMASK(6, 0)
> >
> > +/* Packet type for xmit */
> > +#define QCA_HDR_XMIT_TYPE_NORMAL 0x0
> > +#define QCA_HDR_XMIT_TYPE_RW_REG 0x1
> > +
> > +/* Check code for a valid mgmt packet. Switch will ignore the packet
> > + * with this wrong.
> > + */
> > +#define QCA_HDR_MGMT_CHECK_CODE_VAL 0x5
> > +
> > +/* Specific define for in-band MDIO read/write with Ethernet packet */
> > +#define QCA_HDR_MGMT_SEQ_LEN 4 /* 4 byte for the seq */
> > +#define QCA_HDR_MGMT_COMMAND_LEN 4 /* 4 byte for the command */
> > +#define QCA_HDR_MGMT_DATA1_LEN 4 /* First 4 byte for the mdio data */
> > +#define QCA_HDR_MGMT_HEADER_LEN (QCA_HDR_MGMT_SEQ_LEN + \
> > + QCA_HDR_MGMT_COMMAND_LEN + \
> > + QCA_HDR_MGMT_DATA1_LEN)
> > +
> > +#define QCA_HDR_MGMT_DATA2_LEN 12 /* Other 12 byte for the mdio data */
> > +#define QCA_HDR_MGMT_PADDING_LEN 34 /* Padding to reach the min Ethernet packet */
> > +
> > +#define QCA_HDR_MGMT_PKG_LEN (QCA_HDR_MGMT_HEADER_LEN + \
> > + QCA_HDR_LEN + \
> > + QCA_HDR_MGMT_DATA2_LEN + \
> > + QCA_HDR_MGMT_PADDING_LEN)
>
> s/PKG/PKT/
>
> > +
> > +#define QCA_HDR_MGMT_SEQ_NUM GENMASK(31, 0) /* 63, 32 */
> > +#define QCA_HDR_MGMT_CHECK_CODE GENMASK(31, 29) /* 31, 29 */
> > +#define QCA_HDR_MGMT_CMD BIT(28) /* 28 */
> > +#define QCA_HDR_MGMT_LENGTH GENMASK(23, 20) /* 23, 20 */
> > +#define QCA_HDR_MGMT_ADDR GENMASK(18, 0) /* 18, 0 */
> > +
> > +/* Special struct emulating a Ethernet header */
> > +struct mgmt_ethhdr {
> > + u32 command; /* command bit 31:0 */
> > + u32 seq; /* seq 63:32 */
> > + u32 mdio_data; /* first 4byte mdio */
> > + __be16 hdr; /* qca hdr */
> > +} __packed;
>
> Could you name this something a bit more specific, like qca_mgmt_ethhdr?
>

Sure will fix in v8.

> > +
> > #endif /* __TAG_QCA_H */
> > diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
> > index f8df49d5956f..c57d6e1a0c0c 100644
> > --- a/net/dsa/tag_qca.c
> > +++ b/net/dsa/tag_qca.c
> > @@ -32,10 +32,10 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
> >
> > static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
> > {
> > - u8 ver;
> > - u16 hdr;
> > - int port;
> > + u16 hdr, pk_type;
> > __be16 *phdr;
> > + int port;
> > + u8 ver;
> >
> > if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
> > return NULL;
> > @@ -48,6 +48,13 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
> > if (unlikely(ver != QCA_HDR_VERSION))
> > return NULL;
> >
> > + /* Get pk type */
> > + pk_type = FIELD_GET(QCA_HDR_RECV_TYPE, hdr);
> > +
> > + /* Ethernet MDIO read/write packet */
> > + if (pk_type == QCA_HDR_RECV_TYPE_RW_REG_ACK)
> > + return NULL;
> > +
> > /* Remove QCA tag and recalculate checksum */
> > skb_pull_rcsum(skb, QCA_HDR_LEN);
> > dsa_strip_etype_header(skb, QCA_HDR_LEN);
> > --
> > 2.33.1
> >
>

--
Ansuel