net: cdc_ncm: map MBIM IPS SessionID to VLAN ID

MBIM devices can support up to 256 independent IP Streams.
The main network device will only handle SessionID 0. Mapping
SessionIDs 1 to 255 to VLANs using the SessionID as VLAN ID
allow userspace to use these streams with traditional tools
like vconfig.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c
index 2f21139..45f5f50 100644 (file)
--- a/drivers/net/usb/cdc_mbim.c
+++ b/drivers/net/usb/cdc_mbim.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
+#include <linux/if_vlan.h>
 #include <linux/ip.h>
 #include <linux/mii.h>
 #include <linux/usb.h>
@@ -107,6 +108,9 @@ static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
 
        /* MBIM cannot do ARP */
        dev->net->flags |= IFF_NOARP;
+
+       /* no need to put the VLAN tci in the packet headers */
+       dev->net->features |= NETIF_F_HW_VLAN_TX;
 err:
        return ret;
 }
@@ -131,6 +135,9 @@ static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb
        struct sk_buff *skb_out;
        struct cdc_mbim_state *info = (void *)&dev->data;
        struct cdc_ncm_ctx *ctx = info->ctx;
+       __le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
+       u16 tci = 0;
+       u8 *c;
 
        if (!ctx)
                goto error;
@@ -139,6 +146,24 @@ static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb
                if (skb->len <= sizeof(ETH_HLEN))
                        goto error;
 
+               /* mapping VLANs to MBIM sessions:
+                *   no tag     => IPS session <0>
+                *   1 - 255    => IPS session <vlanid>
+                *   256 - 4095 => unsupported, drop
+                */
+               vlan_get_tag(skb, &tci);
+
+               switch (tci & 0x0f00) {
+               case 0x0000: /* VLAN ID 0 - 255 */
+                       c = (u8 *)&sign;
+                       c[3] = tci;
+                       break;
+               default:
+                       netif_err(dev, tx_err, dev->net,
+                                 "unsupported tci=0x%04x\n", tci);
+                       goto error;
+               }
+
                skb_reset_mac_header(skb);
                switch (eth_hdr(skb)->h_proto) {
                case htons(ETH_P_IP):
@@ -151,7 +176,7 @@ static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb
        }
 
        spin_lock_bh(&ctx->mtx);
-       skb_out = cdc_ncm_fill_tx_frame(ctx, skb, cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN));
+       skb_out = cdc_ncm_fill_tx_frame(ctx, skb, sign);
        spin_unlock_bh(&ctx->mtx);
        return skb_out;
 
@@ -162,11 +187,14 @@ error:
        return NULL;
 }
 
-static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len)
+static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len, u16 tci)
 {
        __be16 proto;
        struct sk_buff *skb = NULL;
 
+       if (len < sizeof(struct iphdr))
+               goto err;
+
        switch (*buf & 0xf0) {
        case 0x40:
                proto = htons(ETH_P_IP);
@@ -191,6 +219,10 @@ static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_
 
        /* add datagram */
        memcpy(skb_put(skb, len), buf, len);
+
+       /* map MBIM session to VLAN */
+       if (tci)
+               vlan_put_tag(skb, tci);
 err:
        return skb;
 }
@@ -198,7 +230,8 @@ err:
 static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 {
        struct sk_buff *skb;
-       struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
+       struct cdc_mbim_state *info = (void *)&dev->data;
+       struct cdc_ncm_ctx *ctx = info->ctx;
        int len;
        int nframes;
        int x;
@@ -207,6 +240,8 @@ static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
        struct usb_cdc_ncm_dpe16 *dpe16;
        int ndpoffset;
        int loopcount = 50; /* arbitrary max preventing infinite loop */
+       u8 *c;
+       u16 tci;
 
        ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
        if (ndpoffset < 0)
@@ -219,9 +254,10 @@ next_ndp:
 
        ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
 
-       /* only supporting IPS Session #0 for now */
-       switch (ndp16->dwSignature) {
+       switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
        case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
+               c = (u8 *)&ndp16->dwSignature;
+               tci = c[3];
                break;
        default:
                netif_dbg(dev, rx_err, dev->net,
@@ -247,8 +283,7 @@ next_ndp:
                }
 
                /* sanity checking */
-               if (((offset + len) > skb_in->len) || (len > ctx->rx_max) ||
-                   (len < sizeof(struct iphdr))) {
+               if (((offset + len) > skb_in->len) || (len > ctx->rx_max)) {
                        netif_dbg(dev, rx_err, dev->net,
                                  "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
                                  x, offset, len, skb_in);
@@ -256,7 +291,7 @@ next_ndp:
                                goto err_ndp;
                        break;
                } else {
-                       skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len);
+                       skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
                        if (!skb)
                                goto error;
                        usbnet_skb_return(dev, skb);