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net: cdc_ncm: splitting rx_fixup for code reuse
Verifying and handling received MBIM and NCM frames will need to be different in three areas: - verifying the NDP signature - checking valid datagram length - datagram header manipulation This makes it inconvenient to share rx_fixup in whole. But some verification parts are common. Split these out in separate functions. Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -966,19 +966,12 @@ error:
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return NULL;
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}
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static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
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/* verify NTB header and return offset of first NDP, or negative error */
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static int cdc_ncm_rx_verify_nth16(struct cdc_ncm_ctx *ctx, struct sk_buff *skb_in)
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{
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struct sk_buff *skb;
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struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
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int len;
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int nframes;
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int x;
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int offset;
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struct usb_cdc_ncm_nth16 *nth16;
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struct usb_cdc_ncm_ndp16 *ndp16;
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struct usb_cdc_ncm_dpe16 *dpe16;
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int ndpoffset;
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int loopcount = 50; /* arbitrary max preventing infinite loop */
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int len;
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int ret = -EINVAL;
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if (ctx == NULL)
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goto error;
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@ -1012,40 +1005,74 @@ static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
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}
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ctx->rx_seq = le16_to_cpu(nth16->wSequence);
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ndpoffset = le16_to_cpu(nth16->wNdpIndex);
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next_ndp:
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ret = le16_to_cpu(nth16->wNdpIndex);
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error:
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return ret;
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}
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/* verify NDP header and return number of datagrams, or negative error */
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static int cdc_ncm_rx_verify_ndp16(struct sk_buff *skb_in, int ndpoffset)
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{
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struct usb_cdc_ncm_ndp16 *ndp16;
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int ret = -EINVAL;
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if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) {
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pr_debug("invalid NDP offset <%u>\n", ndpoffset);
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goto error;
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}
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ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
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if (le32_to_cpu(ndp16->dwSignature) != USB_CDC_NCM_NDP16_NOCRC_SIGN) {
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pr_debug("invalid DPT16 signature <%u>\n",
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le32_to_cpu(ndp16->dwSignature));
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goto err_ndp;
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}
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if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
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pr_debug("invalid DPT16 length <%u>\n",
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le32_to_cpu(ndp16->dwSignature));
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goto err_ndp;
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goto error;
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}
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nframes = ((le16_to_cpu(ndp16->wLength) -
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ret = ((le16_to_cpu(ndp16->wLength) -
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sizeof(struct usb_cdc_ncm_ndp16)) /
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sizeof(struct usb_cdc_ncm_dpe16));
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nframes--; /* we process NDP entries except for the last one */
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ret--; /* we process NDP entries except for the last one */
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ndpoffset += sizeof(struct usb_cdc_ncm_ndp16);
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if ((ndpoffset + nframes * (sizeof(struct usb_cdc_ncm_dpe16))) >
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if ((sizeof(struct usb_cdc_ncm_ndp16) + ret * (sizeof(struct usb_cdc_ncm_dpe16))) >
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skb_in->len) {
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pr_debug("Invalid nframes = %d\n", nframes);
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goto err_ndp;
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pr_debug("Invalid nframes = %d\n", ret);
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ret = -EINVAL;
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}
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dpe16 = (struct usb_cdc_ncm_dpe16 *)(skb_in->data + ndpoffset);
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error:
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return ret;
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}
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static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
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{
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struct sk_buff *skb;
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struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
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int len;
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int nframes;
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int x;
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int offset;
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struct usb_cdc_ncm_ndp16 *ndp16;
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struct usb_cdc_ncm_dpe16 *dpe16;
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int ndpoffset;
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int loopcount = 50; /* arbitrary max preventing infinite loop */
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ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
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if (ndpoffset < 0)
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goto error;
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next_ndp:
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nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
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if (nframes < 0)
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goto error;
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ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
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if (le32_to_cpu(ndp16->dwSignature) != USB_CDC_NCM_NDP16_NOCRC_SIGN) {
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pr_debug("invalid DPT16 signature <%u>\n",
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le32_to_cpu(ndp16->dwSignature));
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goto err_ndp;
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}
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dpe16 = ndp16->dpe16;
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for (x = 0; x < nframes; x++, dpe16++) {
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offset = le16_to_cpu(dpe16->wDatagramIndex);
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