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authorLuiz Angelo Daros de Luca <luizluca@gmail.com>2022-03-02 22:52:34 -0300
committerDavid S. Miller <davem@davemloft.net>2022-03-05 11:04:25 +0000
commitcd87fecdedd7b54c61f5d7c2b7237b43126ac50a (patch)
tree93f1f6bd47d794e6f7e07016848529e560b1c936 /net/dsa
parent617c3cc3aafd826c549b83f055f1e710adbdf99a (diff)
downloadlinux-cd87fecdedd7b54c61f5d7c2b7237b43126ac50a.tar.bz2
net: dsa: tag_rtl8_4: add rtl8_4t trailing variant
Realtek switches supports the same tag both before ethertype or between payload and the CRC. Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com> Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk> Reviewed-by: Vladimir Oltean <olteanv@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dsa')
-rw-r--r--net/dsa/tag_rtl8_4.c152
1 files changed, 116 insertions, 36 deletions
diff --git a/net/dsa/tag_rtl8_4.c b/net/dsa/tag_rtl8_4.c
index 02686ad4045d..71fec45fd0ea 100644
--- a/net/dsa/tag_rtl8_4.c
+++ b/net/dsa/tag_rtl8_4.c
@@ -7,13 +7,8 @@
* NOTE: Currently only supports protocol "4" found in the RTL8365MB, hence
* named tag_rtl8_4.
*
- * This tag header has the following format:
+ * This tag has the following format:
*
- * -------------------------------------------
- * | MAC DA | MAC SA | 8 byte tag | Type | ...
- * -------------------------------------------
- * _______________/ \______________________________________
- * / \
* 0 7|8 15
* |-----------------------------------+-----------------------------------|---
* | (16-bit) | ^
@@ -58,6 +53,24 @@
* TX/RX | TX (switch->CPU): port number the packet was received on
* | RX (CPU->switch): forwarding port mask (if ALLOW=0)
* | allowance port mask (if ALLOW=1)
+ *
+ * The tag can be positioned before Ethertype, using tag "rtl8_4":
+ *
+ * +--------+--------+------------+------+-----
+ * | MAC DA | MAC SA | 8 byte tag | Type | ...
+ * +--------+--------+------------+------+-----
+ *
+ * The tag can also appear between the end of the payload and before the CRC,
+ * using tag "rtl8_4t":
+ *
+ * +--------+--------+------+-----+---------+------------+-----+
+ * | MAC DA | MAC SA | TYPE | ... | payload | 8-byte tag | CRC |
+ * +--------+--------+------+-----+---------+------------+-----+
+ *
+ * The added bytes after the payload will break most checksums, either in
+ * software or hardware. To avoid this issue, if the checksum is still pending,
+ * this tagger checksums the packet in software before adding the tag.
+ *
*/
#include <linux/bitfield.h>
@@ -84,87 +97,133 @@
#define RTL8_4_TX GENMASK(3, 0)
#define RTL8_4_RX GENMASK(10, 0)
-static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb,
- struct net_device *dev)
+static void rtl8_4_write_tag(struct sk_buff *skb, struct net_device *dev,
+ void *tag)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
- __be16 *tag;
-
- skb_push(skb, RTL8_4_TAG_LEN);
-
- dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN);
- tag = dsa_etype_header_pos_tx(skb);
+ __be16 tag16[RTL8_4_TAG_LEN / 2];
/* Set Realtek EtherType */
- tag[0] = htons(ETH_P_REALTEK);
+ tag16[0] = htons(ETH_P_REALTEK);
/* Set Protocol; zero REASON */
- tag[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
+ tag16[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
/* Zero FID_EN, FID, PRI_EN, PRI, KEEP; set LEARN_DIS */
- tag[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1));
+ tag16[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1));
/* Zero ALLOW; set RX (CPU->switch) forwarding port mask */
- tag[3] = htons(FIELD_PREP(RTL8_4_RX, BIT(dp->index)));
+ tag16[3] = htons(FIELD_PREP(RTL8_4_RX, BIT(dp->index)));
+
+ memcpy(tag, tag16, RTL8_4_TAG_LEN);
+}
+
+static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ skb_push(skb, RTL8_4_TAG_LEN);
+
+ dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN);
+
+ rtl8_4_write_tag(skb, dev, dsa_etype_header_pos_tx(skb));
return skb;
}
-static struct sk_buff *rtl8_4_tag_rcv(struct sk_buff *skb,
- struct net_device *dev)
+static struct sk_buff *rtl8_4t_tag_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ /* Calculate the checksum here if not done yet as trailing tags will
+ * break either software or hardware based checksum
+ */
+ if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
+ return NULL;
+
+ rtl8_4_write_tag(skb, dev, skb_put(skb, RTL8_4_TAG_LEN));
+
+ return skb;
+}
+
+static int rtl8_4_read_tag(struct sk_buff *skb, struct net_device *dev,
+ void *tag)
{
- __be16 *tag;
+ __be16 tag16[RTL8_4_TAG_LEN / 2];
u16 etype;
u8 reason;
u8 proto;
u8 port;
- if (unlikely(!pskb_may_pull(skb, RTL8_4_TAG_LEN)))
- return NULL;
-
- tag = dsa_etype_header_pos_rx(skb);
+ memcpy(tag16, tag, RTL8_4_TAG_LEN);
/* Parse Realtek EtherType */
- etype = ntohs(tag[0]);
+ etype = ntohs(tag16[0]);
if (unlikely(etype != ETH_P_REALTEK)) {
dev_warn_ratelimited(&dev->dev,
"non-realtek ethertype 0x%04x\n", etype);
- return NULL;
+ return -EPROTO;
}
/* Parse Protocol */
- proto = FIELD_GET(RTL8_4_PROTOCOL, ntohs(tag[1]));
+ proto = FIELD_GET(RTL8_4_PROTOCOL, ntohs(tag16[1]));
if (unlikely(proto != RTL8_4_PROTOCOL_RTL8365MB)) {
dev_warn_ratelimited(&dev->dev,
"unknown realtek protocol 0x%02x\n",
proto);
- return NULL;
+ return -EPROTO;
}
/* Parse REASON */
- reason = FIELD_GET(RTL8_4_REASON, ntohs(tag[1]));
+ reason = FIELD_GET(RTL8_4_REASON, ntohs(tag16[1]));
/* Parse TX (switch->CPU) */
- port = FIELD_GET(RTL8_4_TX, ntohs(tag[3]));
+ port = FIELD_GET(RTL8_4_TX, ntohs(tag16[3]));
skb->dev = dsa_master_find_slave(dev, 0, port);
if (!skb->dev) {
dev_warn_ratelimited(&dev->dev,
"could not find slave for port %d\n",
port);
- return NULL;
+ return -ENOENT;
}
+ if (reason != RTL8_4_REASON_TRAP)
+ dsa_default_offload_fwd_mark(skb);
+
+ return 0;
+}
+
+static struct sk_buff *rtl8_4_tag_rcv(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ if (unlikely(!pskb_may_pull(skb, RTL8_4_TAG_LEN)))
+ return NULL;
+
+ if (unlikely(rtl8_4_read_tag(skb, dev, dsa_etype_header_pos_rx(skb))))
+ return NULL;
+
/* Remove tag and recalculate checksum */
skb_pull_rcsum(skb, RTL8_4_TAG_LEN);
dsa_strip_etype_header(skb, RTL8_4_TAG_LEN);
- if (reason != RTL8_4_REASON_TRAP)
- dsa_default_offload_fwd_mark(skb);
+ return skb;
+}
+
+static struct sk_buff *rtl8_4t_tag_rcv(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ if (skb_linearize(skb))
+ return NULL;
+
+ if (unlikely(rtl8_4_read_tag(skb, dev, skb_tail_pointer(skb) - RTL8_4_TAG_LEN)))
+ return NULL;
+
+ if (pskb_trim_rcsum(skb, skb->len - RTL8_4_TAG_LEN))
+ return NULL;
return skb;
}
+/* Ethertype version */
static const struct dsa_device_ops rtl8_4_netdev_ops = {
.name = "rtl8_4",
.proto = DSA_TAG_PROTO_RTL8_4,
@@ -172,7 +231,28 @@ static const struct dsa_device_ops rtl8_4_netdev_ops = {
.rcv = rtl8_4_tag_rcv,
.needed_headroom = RTL8_4_TAG_LEN,
};
-module_dsa_tag_driver(rtl8_4_netdev_ops);
-MODULE_LICENSE("GPL");
+DSA_TAG_DRIVER(rtl8_4_netdev_ops);
+
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL8_4);
+
+/* Tail version */
+static const struct dsa_device_ops rtl8_4t_netdev_ops = {
+ .name = "rtl8_4t",
+ .proto = DSA_TAG_PROTO_RTL8_4T,
+ .xmit = rtl8_4t_tag_xmit,
+ .rcv = rtl8_4t_tag_rcv,
+ .needed_tailroom = RTL8_4_TAG_LEN,
+};
+
+DSA_TAG_DRIVER(rtl8_4t_netdev_ops);
+
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL8_4L);
+
+static struct dsa_tag_driver *dsa_tag_drivers[] = {
+ &DSA_TAG_DRIVER_NAME(rtl8_4_netdev_ops),
+ &DSA_TAG_DRIVER_NAME(rtl8_4t_netdev_ops),
+};
+module_dsa_tag_drivers(dsa_tag_drivers);
+
+MODULE_LICENSE("GPL");