diff options
| -rw-r--r-- | drivers/net/usb/qmi_wwan.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c index 968d5d50751d..2a3579f67910 100644 --- a/drivers/net/usb/qmi_wwan.c +++ b/drivers/net/usb/qmi_wwan.c @@ -13,6 +13,7 @@ #include <linux/module.h> #include <linux/netdevice.h> #include <linux/ethtool.h> +#include <linux/etherdevice.h> #include <linux/mii.h> #include <linux/usb.h> #include <linux/usb/cdc.h> @@ -52,6 +53,96 @@ struct qmi_wwan_state { struct usb_interface *data; }; +/* default ethernet address used by the modem */ +static const u8 default_modem_addr[ETH_ALEN] = {0x02, 0x50, 0xf3}; + +/* Make up an ethernet header if the packet doesn't have one. + * + * A firmware bug common among several devices cause them to send raw + * IP packets under some circumstances. There is no way for the + * driver/host to know when this will happen. And even when the bug + * hits, some packets will still arrive with an intact header. + * + * The supported devices are only capably of sending IPv4, IPv6 and + * ARP packets on a point-to-point link. Any packet with an ethernet + * header will have either our address or a broadcast/multicast + * address as destination. ARP packets will always have a header. + * + * This means that this function will reliably add the appropriate + * header iff necessary, provided our hardware address does not start + * with 4 or 6. + * + * Another common firmware bug results in all packets being addressed + * to 00:a0:c6:00:00:00 despite the host address being different. + * This function will also fixup such packets. + */ +static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb) +{ + __be16 proto; + + /* usbnet rx_complete guarantees that skb->len is at least + * hard_header_len, so we can inspect the dest address without + * checking skb->len + */ + switch (skb->data[0] & 0xf0) { + case 0x40: + proto = htons(ETH_P_IP); + break; + case 0x60: + proto = htons(ETH_P_IPV6); + break; + case 0x00: + if (is_multicast_ether_addr(skb->data)) + return 1; + /* possibly bogus destination - rewrite just in case */ + skb_reset_mac_header(skb); + goto fix_dest; + default: + /* pass along other packets without modifications */ + return 1; + } + if (skb_headroom(skb) < ETH_HLEN) + return 0; + skb_push(skb, ETH_HLEN); + skb_reset_mac_header(skb); + eth_hdr(skb)->h_proto = proto; + memset(eth_hdr(skb)->h_source, 0, ETH_ALEN); +fix_dest: + memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN); + return 1; +} + +/* very simplistic detection of IPv4 or IPv6 headers */ +static bool possibly_iphdr(const char *data) +{ + return (data[0] & 0xd0) == 0x40; +} + +/* disallow addresses which may be confused with IP headers */ +static int qmi_wwan_mac_addr(struct net_device *dev, void *p) +{ + int ret; + struct sockaddr *addr = p; + + ret = eth_prepare_mac_addr_change(dev, p); + if (ret < 0) + return ret; + if (possibly_iphdr(addr->sa_data)) + return -EADDRNOTAVAIL; + eth_commit_mac_addr_change(dev, p); + return 0; +} + +static const struct net_device_ops qmi_wwan_netdev_ops = { + .ndo_open = usbnet_open, + .ndo_stop = usbnet_stop, + .ndo_start_xmit = usbnet_start_xmit, + .ndo_tx_timeout = usbnet_tx_timeout, + .ndo_change_mtu = usbnet_change_mtu, + .ndo_set_mac_address = qmi_wwan_mac_addr, + .ndo_validate_addr = eth_validate_addr, +}; + /* using a counter to merge subdriver requests with our own into a combined state */ static int qmi_wwan_manage_power(struct usbnet *dev, int on) { @@ -229,6 +320,18 @@ next_desc: usb_driver_release_interface(driver, info->data); } + /* Never use the same address on both ends of the link, even + * if the buggy firmware told us to. + */ + if (!compare_ether_addr(dev->net->dev_addr, default_modem_addr)) + eth_hw_addr_random(dev->net); + + /* make MAC addr easily distinguishable from an IP header */ + if (possibly_iphdr(dev->net->dev_addr)) { + dev->net->dev_addr[0] |= 0x02; /* set local assignment bit */ + dev->net->dev_addr[0] &= 0xbf; /* clear "IP" bit */ + } + dev->net->netdev_ops = &qmi_wwan_netdev_ops; err: return status; } @@ -307,6 +410,7 @@ static const struct driver_info qmi_wwan_info = { .bind = qmi_wwan_bind, .unbind = qmi_wwan_unbind, .manage_power = qmi_wwan_manage_power, + .rx_fixup = qmi_wwan_rx_fixup, }; #define HUAWEI_VENDOR_ID 0x12D1 |