[PATCH net-next v2 1/3] dsa: Implement RMU layer in DSA

Mattias Forsblad
2022-08-26T06:38:29Z

Support handling of layer 2 part for RMU frames which is
handled in-band with other DSA traffic.

Signed-off-by: Mattias Forsblad <mattias.forsblad@gmail.com>
---
include/net/dsa.h | 7 +++
include/uapi/linux/if_ether.h | 1 +
net/dsa/tag_dsa.c | 109 +++++++++++++++++++++++++++++++++-
3 files changed, 114 insertions(+), 3 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index f2ce12860546..54f7f3494f84 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -92,6 +92,7 @@ struct dsa_switch;
struct dsa_device_ops {
struct sk_buff *(*xmit)(struct sk_buff *skb, struct net_device *dev);
struct sk_buff *(*rcv)(struct sk_buff *skb, struct net_device *dev);
+ int (*inband_xmit)(struct sk_buff *skb, struct net_device *dev, int seq_no);
void (*flow_dissect)(const struct sk_buff *skb, __be16 *proto,
int *offset);
int (*connect)(struct dsa_switch *ds);
@@ -1193,6 +1194,12 @@ struct dsa_switch_ops {
void (*master_state_change)(struct dsa_switch *ds,
const struct net_device *master,
bool operational);
+
+ /*
+ * RMU operations
+ */
+ int (*inband_receive)(struct dsa_switch *ds, struct sk_buff *skb,
+ int seq_no);
};

#define DSA_DEVLINK_PARAM_DRIVER(_id, _name, _type, _cmodes) \
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index d370165bc621..9de1bdc7cccc 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -158,6 +158,7 @@
#define ETH_P_MCTP 0x00FA /* Management component transport
* protocol packets
*/
+#define ETH_P_RMU_DSA 0x00FB /* RMU DSA protocol */

/*
* This is an Ethernet frame header.
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index e4b6e3f2a3db..36f02e7dd3c3 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -123,6 +123,90 @@ enum dsa_code {
DSA_CODE_RESERVED_7 = 7
};

+#define DSA_RMU_RESV1 0x3e
+#define DSA_RMU 1
+#define DSA_RMU_PRIO 6
+#define DSA_RMU_RESV2 0xf
+
+static int dsa_inband_xmit_ll(struct sk_buff *skb, struct net_device *dev,
+ const u8 *header, int header_len, int seq_no)
+{
+ static const u8 dest_addr[ETH_ALEN] = { 0x01, 0x50, 0x43, 0x00, 0x00, 0x00 };
+ struct dsa_port *dp;
+ struct ethhdr *eth;
+ u8 *data;
+
+ if (!dev)
+ return -ENODEV;
+
+ dp = dsa_slave_to_port(dev);
+ if (!dp)
+ return -ENODEV;
+
+ /* Create RMU L2 header */
+ data = skb_push(skb, 6);
+ data[0] = (DSA_CMD_FROM_CPU << 6) | dp->ds->index;
+ data[1] = DSA_RMU_RESV1 << 2 | DSA_RMU << 1;
+ data[2] = DSA_RMU_PRIO << 5 | DSA_RMU_RESV2;
+ data[3] = seq_no;
+ data[4] = 0;
+ data[5] = 0;
+
+ /* Add header if any */
+ if (header) {
+ data = skb_push(skb, header_len);
+ memcpy(data, header, header_len);
+ }
+
+ /* Create MAC header */
+ eth = (struct ethhdr *)skb_push(skb, 2 * ETH_ALEN);
+ memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
+ memcpy(eth->h_dest, dest_addr, ETH_ALEN);
+
+ skb->protocol = htons(ETH_P_RMU_DSA);
+
+ dev_queue_xmit(skb);
+
+ return 0;
+}
+
+static int dsa_inband_rcv_ll(struct sk_buff *skb, struct net_device *dev)
+{
+ struct dsa_switch *ds;
+ int source_device;
+ u8 *dsa_header;
+ int rcv_seqno;
+ int ret = 0;
+
+ if (!dev || !dev->dsa_ptr)
+ return 0;
+
+ ds = dev->dsa_ptr->ds;
+ if (!ds)
+ return 0;
+
+ dsa_header = skb->data - 2;
+
+ source_device = dsa_header[0] & 0x1f;
+ ds = dsa_switch_find(ds->dst->index, source_device);
+ if (!ds) {
+ net_dbg_ratelimited("DSA inband: Didn't find switch with index %d", source_device);
+ return -EINVAL;
+ }
+
+ /* Get rcv seqno */
+ rcv_seqno = dsa_header[3];
+
+ skb_pull(skb, DSA_HLEN);
+
+ if (ds->ops && ds->ops->inband_receive(ds, skb, rcv_seqno)) {
+ dev_dbg_ratelimited(ds->dev, "DSA inband: error decoding packet");
+ ret = -EIO;
+ }
+
+ return ret;
+}
+
static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
u8 extra)
{
@@ -218,9 +302,7 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,

switch (code) {
case DSA_CODE_FRAME2REG:
- /* Remote management is not implemented yet,
- * drop.
- */
+ dsa_inband_rcv_ll(skb, dev);
return NULL;
case DSA_CODE_ARP_MIRROR:
case DSA_CODE_POLICY_MIRROR:
@@ -325,6 +407,12 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,

#if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA)

+static int dsa_inband_xmit(struct sk_buff *skb, struct net_device *dev,
+ int seq_no)
+{
+ return dsa_inband_xmit_ll(skb, dev, NULL, 0, seq_no);
+}
+
static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
return dsa_xmit_ll(skb, dev, 0);
@@ -343,6 +431,7 @@ static const struct dsa_device_ops dsa_netdev_ops = {
.proto = DSA_TAG_PROTO_DSA,
.xmit = dsa_xmit,
.rcv = dsa_rcv,
+ .inband_xmit = dsa_inband_xmit,
.needed_headroom = DSA_HLEN,
};

@@ -354,6 +443,19 @@ MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA);

#define EDSA_HLEN 8

+static int edsa_inband_xmit(struct sk_buff *skb, struct net_device *dev,
+ int seq_no)
+{
+ u8 edsa_header[4];
+
+ edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
+ edsa_header[1] = ETH_P_EDSA & 0xff;
+ edsa_header[2] = 0x00;
+ edsa_header[3] = 0x00;
+
+ return dsa_inband_xmit_ll(skb, dev, edsa_header, 4, seq_no);
+}
+
static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
u8 *edsa_header;
@@ -385,6 +487,7 @@ static const struct dsa_device_ops edsa_netdev_ops = {
.proto = DSA_TAG_PROTO_EDSA,
.xmit = edsa_xmit,
.rcv = edsa_rcv,
+ .inband_xmit = edsa_inband_xmit,
.needed_headroom = EDSA_HLEN,
};

--
2.25.1