diff options
Diffstat (limited to 'drivers/net/usb/lg-vl600.c')
| -rw-r--r-- | drivers/net/usb/lg-vl600.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/net/usb/lg-vl600.c b/drivers/net/usb/lg-vl600.c new file mode 100644 index 000000000..b2495fa80 --- /dev/null +++ b/drivers/net/usb/lg-vl600.c @@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Ethernet interface part of the LG VL600 LTE modem (4G dongle) + * + * Copyright (C) 2011 Intel Corporation + * Author: Andrzej Zaborowski <balrogg@gmail.com> + */ +#include <linux/etherdevice.h> +#include <linux/ethtool.h> +#include <linux/mii.h> +#include <linux/usb.h> +#include <linux/usb/cdc.h> +#include <linux/usb/usbnet.h> +#include <linux/if_ether.h> +#include <linux/if_arp.h> +#include <linux/inetdevice.h> +#include <linux/module.h> + +/* + * The device has a CDC ACM port for modem control (it claims to be + * CDC ACM anyway) and a CDC Ethernet port for actual network data. + * It will however ignore data on both ports that is not encapsulated + * in a specific way, any data returned is also encapsulated the same + * way. The headers don't seem to follow any popular standard. + * + * This driver adds and strips these headers from the ethernet frames + * sent/received from the CDC Ethernet port. The proprietary header + * replaces the standard ethernet header in a packet so only actual + * ethernet frames are allowed. The headers allow some form of + * multiplexing by using non standard values of the .h_proto field. + * Windows/Mac drivers do send a couple of such frames to the device + * during initialisation, with protocol set to 0x0906 or 0x0b06 and (what + * seems to be) a flag in the .dummy_flags. This doesn't seem necessary + * for modem operation but can possibly be used for GPS or other functions. + */ + +struct vl600_frame_hdr { + __le32 len; + __le32 serial; + __le32 pkt_cnt; + __le32 dummy_flags; + __le32 dummy; + __le32 magic; +} __attribute__((packed)); + +struct vl600_pkt_hdr { + __le32 dummy[2]; + __le32 len; + __be16 h_proto; +} __attribute__((packed)); + +struct vl600_state { + struct sk_buff *current_rx_buf; +}; + +static int vl600_bind(struct usbnet *dev, struct usb_interface *intf) +{ + int ret; + struct vl600_state *s = kzalloc(sizeof(struct vl600_state), GFP_KERNEL); + + if (!s) + return -ENOMEM; + + ret = usbnet_cdc_bind(dev, intf); + if (ret) { + kfree(s); + return ret; + } + + dev->driver_priv = s; + + /* ARP packets don't go through, but they're also of no use. The + * subnet has only two hosts anyway: us and the gateway / DHCP + * server (probably simulated by modem firmware or network operator) + * whose address changes every time we connect to the intarwebz and + * who doesn't bother answering ARP requests either. So hardware + * addresses have no meaning, the destination and the source of every + * packet depend only on whether it is on the IN or OUT endpoint. */ + dev->net->flags |= IFF_NOARP; + /* IPv6 NDP relies on multicast. Enable it by default. */ + dev->net->flags |= IFF_MULTICAST; + + return ret; +} + +static void vl600_unbind(struct usbnet *dev, struct usb_interface *intf) +{ + struct vl600_state *s = dev->driver_priv; + + dev_kfree_skb(s->current_rx_buf); + kfree(s); + + return usbnet_cdc_unbind(dev, intf); +} + +static int vl600_rx_fixup(struct usbnet *dev, struct sk_buff *skb) +{ + struct vl600_frame_hdr *frame; + struct vl600_pkt_hdr *packet; + struct ethhdr *ethhdr; + int packet_len, count; + struct sk_buff *buf = skb; + struct sk_buff *clone; + struct vl600_state *s = dev->driver_priv; + + /* Frame lengths are generally 4B multiplies but every couple of + * hours there's an odd number of bytes sized yet correct frame, + * so don't require this. */ + + /* Allow a packet (or multiple packets batched together) to be + * split across many frames. We don't allow a new batch to + * begin in the same frame another one is ending however, and no + * leading or trailing pad bytes. */ + if (s->current_rx_buf) { + frame = (struct vl600_frame_hdr *) s->current_rx_buf->data; + if (skb->len + s->current_rx_buf->len > + le32_to_cpup(&frame->len)) { + netif_err(dev, ifup, dev->net, "Fragment too long\n"); + dev->net->stats.rx_length_errors++; + goto error; + } + + buf = s->current_rx_buf; + skb_put_data(buf, skb->data, skb->len); + } else if (skb->len < 4) { + netif_err(dev, ifup, dev->net, "Frame too short\n"); + dev->net->stats.rx_length_errors++; + goto error; + } + + frame = (struct vl600_frame_hdr *) buf->data; + /* Yes, check that frame->magic == 0x53544448 (or 0x44544d48), + * otherwise we may run out of memory w/a bad packet */ + if (ntohl(frame->magic) != 0x53544448 && + ntohl(frame->magic) != 0x44544d48) + goto error; + + if (buf->len < sizeof(*frame) || + buf->len != le32_to_cpup(&frame->len)) { + /* Save this fragment for later assembly */ + if (s->current_rx_buf) + return 0; + + s->current_rx_buf = skb_copy_expand(skb, 0, + le32_to_cpup(&frame->len), GFP_ATOMIC); + if (!s->current_rx_buf) + dev->net->stats.rx_errors++; + + return 0; + } + + count = le32_to_cpup(&frame->pkt_cnt); + + skb_pull(buf, sizeof(*frame)); + + while (count--) { + if (buf->len < sizeof(*packet)) { + netif_err(dev, ifup, dev->net, "Packet too short\n"); + goto error; + } + + packet = (struct vl600_pkt_hdr *) buf->data; + packet_len = sizeof(*packet) + le32_to_cpup(&packet->len); + if (packet_len > buf->len) { + netif_err(dev, ifup, dev->net, + "Bad packet length stored in header\n"); + goto error; + } + + /* Packet header is same size as the ethernet header + * (sizeof(*packet) == sizeof(*ethhdr)), additionally + * the h_proto field is in the same place so we just leave it + * alone and fill in the remaining fields. + */ + ethhdr = (struct ethhdr *) skb->data; + if (be16_to_cpup(ðhdr->h_proto) == ETH_P_ARP && + buf->len > 0x26) { + /* Copy the addresses from packet contents */ + memcpy(ethhdr->h_source, + &buf->data[sizeof(*ethhdr) + 0x8], + ETH_ALEN); + memcpy(ethhdr->h_dest, + &buf->data[sizeof(*ethhdr) + 0x12], + ETH_ALEN); + } else { + eth_zero_addr(ethhdr->h_source); + memcpy(ethhdr->h_dest, dev->net->dev_addr, ETH_ALEN); + + /* Inbound IPv6 packets have an IPv4 ethertype (0x800) + * for some reason. Peek at the L3 header to check + * for IPv6 packets, and set the ethertype to IPv6 + * (0x86dd) so Linux can understand it. + */ + if ((buf->data[sizeof(*ethhdr)] & 0xf0) == 0x60) + ethhdr->h_proto = htons(ETH_P_IPV6); + } + + if (count) { + /* Not the last packet in this batch */ + clone = skb_clone(buf, GFP_ATOMIC); + if (!clone) + goto error; + + skb_trim(clone, packet_len); + usbnet_skb_return(dev, clone); + + skb_pull(buf, (packet_len + 3) & ~3); + } else { + skb_trim(buf, packet_len); + + if (s->current_rx_buf) { + usbnet_skb_return(dev, buf); + s->current_rx_buf = NULL; + return 0; + } + + return 1; + } + } + +error: + if (s->current_rx_buf) { + dev_kfree_skb_any(s->current_rx_buf); + s->current_rx_buf = NULL; + } + dev->net->stats.rx_errors++; + return 0; +} + +static struct sk_buff *vl600_tx_fixup(struct usbnet *dev, + struct sk_buff *skb, gfp_t flags) +{ + struct sk_buff *ret; + struct vl600_frame_hdr *frame; + struct vl600_pkt_hdr *packet; + static uint32_t serial = 1; + int orig_len = skb->len - sizeof(struct ethhdr); + int full_len = (skb->len + sizeof(struct vl600_frame_hdr) + 3) & ~3; + + frame = (struct vl600_frame_hdr *) skb->data; + if (skb->len > sizeof(*frame) && skb->len == le32_to_cpup(&frame->len)) + return skb; /* Already encapsulated? */ + + if (skb->len < sizeof(struct ethhdr)) + /* Drop, device can only deal with ethernet packets */ + return NULL; + + if (!skb_cloned(skb)) { + int headroom = skb_headroom(skb); + int tailroom = skb_tailroom(skb); + + if (tailroom >= full_len - skb->len - sizeof(*frame) && + headroom >= sizeof(*frame)) + /* There's enough head and tail room */ + goto encapsulate; + + if (headroom + tailroom + skb->len >= full_len) { + /* There's enough total room, just readjust */ + skb->data = memmove(skb->head + sizeof(*frame), + skb->data, skb->len); + skb_set_tail_pointer(skb, skb->len); + goto encapsulate; + } + } + + /* Alloc a new skb with the required size */ + ret = skb_copy_expand(skb, sizeof(struct vl600_frame_hdr), full_len - + skb->len - sizeof(struct vl600_frame_hdr), flags); + dev_kfree_skb_any(skb); + if (!ret) + return ret; + skb = ret; + +encapsulate: + /* Packet header is same size as ethernet packet header + * (sizeof(*packet) == sizeof(struct ethhdr)), additionally the + * h_proto field is in the same place so we just leave it alone and + * overwrite the remaining fields. + */ + packet = (struct vl600_pkt_hdr *) skb->data; + /* The VL600 wants IPv6 packets to have an IPv4 ethertype + * Since this modem only supports IPv4 and IPv6, just set all + * frames to 0x0800 (ETH_P_IP) + */ + packet->h_proto = htons(ETH_P_IP); + memset(&packet->dummy, 0, sizeof(packet->dummy)); + packet->len = cpu_to_le32(orig_len); + + frame = skb_push(skb, sizeof(*frame)); + memset(frame, 0, sizeof(*frame)); + frame->len = cpu_to_le32(full_len); + frame->serial = cpu_to_le32(serial++); + frame->pkt_cnt = cpu_to_le32(1); + + if (skb->len < full_len) /* Pad */ + skb_put(skb, full_len - skb->len); + + return skb; +} + +static const struct driver_info vl600_info = { + .description = "LG VL600 modem", + .flags = FLAG_RX_ASSEMBLE | FLAG_WWAN, + .bind = vl600_bind, + .unbind = vl600_unbind, + .status = usbnet_cdc_status, + .rx_fixup = vl600_rx_fixup, + .tx_fixup = vl600_tx_fixup, +}; + +static const struct usb_device_id products[] = { + { + USB_DEVICE_AND_INTERFACE_INFO(0x1004, 0x61aa, USB_CLASS_COMM, + USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE), + .driver_info = (unsigned long) &vl600_info, + }, + {}, /* End */ +}; +MODULE_DEVICE_TABLE(usb, products); + +static struct usb_driver lg_vl600_driver = { + .name = "lg-vl600", + .id_table = products, + .probe = usbnet_probe, + .disconnect = usbnet_disconnect, + .suspend = usbnet_suspend, + .resume = usbnet_resume, + .disable_hub_initiated_lpm = 1, +}; + +module_usb_driver(lg_vl600_driver); + +MODULE_AUTHOR("Anrzej Zaborowski"); +MODULE_DESCRIPTION("LG-VL600 modem's ethernet link"); +MODULE_LICENSE("GPL"); |