[PATCH net-next v4 2/3] net: dsa: tag_rtl8_4: add rtl8_4t trailing variant
From: Luiz Angelo Daros de Luca <hidden>
Date: 2022-02-27 04:00:03
Subsystem:
networking [dsa], networking [general], the rest · Maintainers:
Andrew Lunn, Vladimir Oltean, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Realtek switches supports the same tag both before ethertype or between payload and the CRC. Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk> Signed-off-by: Luiz Angelo Daros de Luca <redacted> --- include/net/dsa.h | 2 + net/dsa/tag_rtl8_4.c | 150 +++++++++++++++++++++++++++++++++---------- 2 files changed, 117 insertions(+), 35 deletions(-)
diff --git a/include/net/dsa.h b/include/net/dsa.h
index fd1f62a6e0a8..b688ced04b0e 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h@@ -52,6 +52,7 @@ struct phylink_link_state; #define DSA_TAG_PROTO_BRCM_LEGACY_VALUE 22 #define DSA_TAG_PROTO_SJA1110_VALUE 23 #define DSA_TAG_PROTO_RTL8_4_VALUE 24 +#define DSA_TAG_PROTO_RTL8_4T_VALUE 25 enum dsa_tag_protocol { DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE,
@@ -79,6 +80,7 @@ enum dsa_tag_protocol { DSA_TAG_PROTO_SEVILLE = DSA_TAG_PROTO_SEVILLE_VALUE, DSA_TAG_PROTO_SJA1110 = DSA_TAG_PROTO_SJA1110_VALUE, DSA_TAG_PROTO_RTL8_4 = DSA_TAG_PROTO_RTL8_4_VALUE, + DSA_TAG_PROTO_RTL8_4T = DSA_TAG_PROTO_RTL8_4T_VALUE, }; struct dsa_switch;
diff --git a/net/dsa/tag_rtl8_4.c b/net/dsa/tag_rtl8_4.c
index 02686ad4045d..bf34b257b193 100644
--- a/net/dsa/tag_rtl8_4.c
+++ b/net/dsa/tag_rtl8_4.c@@ -9,11 +9,6 @@ * * This tag header 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 checksum 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 and 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");
--
2.35.1