diff options
| -rw-r--r-- | include/net/dsa.h | 2 | ||||
| -rw-r--r-- | net/dsa/Kconfig | 7 | ||||
| -rw-r--r-- | net/dsa/Makefile | 1 | ||||
| -rw-r--r-- | net/dsa/tag_rtl4_a.c | 130 |
4 files changed, 140 insertions, 0 deletions
diff --git a/include/net/dsa.h b/include/net/dsa.h index 4046ccd1945d..b28c95c76762 100644 --- a/include/net/dsa.h +++ b/include/net/dsa.h @@ -44,6 +44,7 @@ struct phylink_link_state; #define DSA_TAG_PROTO_KSZ8795_VALUE 14 #define DSA_TAG_PROTO_OCELOT_VALUE 15 #define DSA_TAG_PROTO_AR9331_VALUE 16 +#define DSA_TAG_PROTO_RTL4_A_VALUE 17 enum dsa_tag_protocol { DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE, @@ -63,6 +64,7 @@ enum dsa_tag_protocol { DSA_TAG_PROTO_KSZ8795 = DSA_TAG_PROTO_KSZ8795_VALUE, DSA_TAG_PROTO_OCELOT = DSA_TAG_PROTO_OCELOT_VALUE, DSA_TAG_PROTO_AR9331 = DSA_TAG_PROTO_AR9331_VALUE, + DSA_TAG_PROTO_RTL4_A = DSA_TAG_PROTO_RTL4_A_VALUE, }; struct packet_type; diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig index d5bc6ac599ef..1f9b9b11008c 100644 --- a/net/dsa/Kconfig +++ b/net/dsa/Kconfig @@ -86,6 +86,13 @@ config NET_DSA_TAG_KSZ Say Y if you want to enable support for tagging frames for the Microchip 8795/9477/9893 families of switches. +config NET_DSA_TAG_RTL4_A + tristate "Tag driver for Realtek 4 byte protocol A tags" + help + Say Y or M if you want to enable support for tagging frames for the + Realtek switches with 4 byte protocol A tags, sich as found in + the Realtek RTL8366RB. + config NET_DSA_TAG_OCELOT tristate "Tag driver for Ocelot family of switches" select PACKING diff --git a/net/dsa/Makefile b/net/dsa/Makefile index 108486cfdeef..4f47b2025ff5 100644 --- a/net/dsa/Makefile +++ b/net/dsa/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o +obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c new file mode 100644 index 000000000000..7b63010fa87b --- /dev/null +++ b/net/dsa/tag_rtl4_a.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Handler for Realtek 4 byte DSA switch tags + * Currently only supports protocol "A" found in RTL8366RB + * Copyright (c) 2020 Linus Walleij <linus.walleij@linaro.org> + * + * This "proprietary tag" header looks like so: + * + * ------------------------------------------------- + * | MAC DA | MAC SA | 0x8899 | 2 bytes tag | Type | + * ------------------------------------------------- + * + * The 2 bytes tag form a 16 bit big endian word. The exact + * meaning has been guessed from packet dumps from ingress + * frames, as no working egress traffic has been available + * we do not know the format of the egress tags or if they + * are even supported. + */ + +#include <linux/etherdevice.h> +#include <linux/bits.h> + +#include "dsa_priv.h" + +#define RTL4_A_HDR_LEN 4 +#define RTL4_A_ETHERTYPE 0x8899 +#define RTL4_A_PROTOCOL_SHIFT 12 +/* + * 0x1 = Realtek Remote Control protocol (RRCP) + * 0x2/0x3 seems to be used for loopback testing + * 0x9 = RTL8306 DSA protocol + * 0xa = RTL8366RB DSA protocol + */ +#define RTL4_A_PROTOCOL_RTL8366RB 0xa + +static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + /* + * Just let it pass thru, we don't know if it is possible + * to tag a frame with the 0x8899 ethertype and direct it + * to a specific port, all attempts at reverse-engineering have + * ended up with the frames getting dropped. + * + * The VLAN set-up needs to restrict the frames to the right port. + * + * If you have documentation on the tagging format for RTL8366RB + * (tag type A) then please contribute. + */ + return skb; +} + +static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb, + struct net_device *dev, + struct packet_type *pt) +{ + u16 protport; + __be16 *p; + u16 etype; + u8 *tag; + u8 prot; + u8 port; + + if (unlikely(!pskb_may_pull(skb, RTL4_A_HDR_LEN))) + return NULL; + + /* The RTL4 header has its own custom Ethertype 0x8899 and that + * starts right at the beginning of the packet, after the src + * ethernet addr. Apparantly skb->data always points 2 bytes in, + * behind the Ethertype. + */ + tag = skb->data - 2; + p = (__be16 *)tag; + etype = ntohs(*p); + if (etype != RTL4_A_ETHERTYPE) { + /* Not custom, just pass through */ + netdev_dbg(dev, "non-realtek ethertype 0x%04x\n", etype); + return skb; + } + p = (__be16 *)(tag + 2); + protport = ntohs(*p); + /* The 4 upper bits are the protocol */ + prot = (protport >> RTL4_A_PROTOCOL_SHIFT) & 0x0f; + if (prot != RTL4_A_PROTOCOL_RTL8366RB) { + netdev_err(dev, "unknown realtek protocol 0x%01x\n", prot); + return NULL; + } + port = protport & 0xff; + + skb->dev = dsa_master_find_slave(dev, 0, port); + if (!skb->dev) { + netdev_dbg(dev, "could not find slave for port %d\n", port); + return NULL; + } + + /* Remove RTL4 tag and recalculate checksum */ + skb_pull_rcsum(skb, RTL4_A_HDR_LEN); + + /* Move ethernet DA and SA in front of the data */ + memmove(skb->data - ETH_HLEN, + skb->data - ETH_HLEN - RTL4_A_HDR_LEN, + 2 * ETH_ALEN); + + skb->offload_fwd_mark = 1; + + return skb; +} + +static int rtl4a_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto, + int *offset) +{ + *offset = RTL4_A_HDR_LEN; + /* Skip past the tag and fetch the encapsulated Ethertype */ + *proto = ((__be16 *)skb->data)[1]; + + return 0; +} + +static const struct dsa_device_ops rtl4a_netdev_ops = { + .name = "rtl4a", + .proto = DSA_TAG_PROTO_RTL4_A, + .xmit = rtl4a_tag_xmit, + .rcv = rtl4a_tag_rcv, + .flow_dissect = rtl4a_tag_flow_dissect, + .overhead = RTL4_A_HDR_LEN, +}; +module_dsa_tag_driver(rtl4a_netdev_ops); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL4_A); |