From: Jeremy Kerr jk@ozlabs.org
[ Upstream commit e869e7a17798d85829fa7d4f9bbe1eebd4b2d3f6 ]
Using a AX88179 device (0b95:1790), I see two bytes of appended data on every RX packet. For example, this 48-byte ping, using 0xff as a payload byte:
04:20:22.528472 IP 192.168.1.1 > 192.168.1.2: ICMP echo request, id 2447, seq 1, length 64 0x0000: 000a cd35 ea50 000a cd35 ea4f 0800 4500 0x0010: 0054 c116 4000 4001 f63e c0a8 0101 c0a8 0x0020: 0102 0800 b633 098f 0001 87ea cd5e 0000 0x0030: 0000 dcf2 0600 0000 0000 ffff ffff ffff 0x0040: ffff ffff ffff ffff ffff ffff ffff ffff 0x0050: ffff ffff ffff ffff ffff ffff ffff ffff 0x0060: ffff 961f
Those last two bytes - 96 1f - aren't part of the original packet.
In the ax88179 RX path, the usbnet rx_fixup function trims a 2-byte 'alignment pseudo header' from the start of the packet, and sets the length from a per-packet field populated by hardware. It looks like that length field *includes* the 2-byte header; the current driver assumes that it's excluded.
This change trims the 2-byte alignment header after we've set the packet length, so the resulting packet length is correct. While we're moving the comment around, this also fixes the spelling of 'pseudo'.
Signed-off-by: Jeremy Kerr jk@ozlabs.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/usb/ax88179_178a.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c index daa54486ab094..df2f7cc6dc03a 100644 --- a/drivers/net/usb/ax88179_178a.c +++ b/drivers/net/usb/ax88179_178a.c @@ -1387,10 +1387,10 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct sk_buff *skb) }
if (pkt_cnt == 0) { - /* Skip IP alignment psudo header */ - skb_pull(skb, 2); skb->len = pkt_len; - skb_set_tail_pointer(skb, pkt_len); + /* Skip IP alignment pseudo header */ + skb_pull(skb, 2); + skb_set_tail_pointer(skb, skb->len); skb->truesize = pkt_len + sizeof(struct sk_buff); ax88179_rx_checksum(skb, pkt_hdr); return 1; @@ -1399,8 +1399,9 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct sk_buff *skb) ax_skb = skb_clone(skb, GFP_ATOMIC); if (ax_skb) { ax_skb->len = pkt_len; - ax_skb->data = skb->data + 2; - skb_set_tail_pointer(ax_skb, pkt_len); + /* Skip IP alignment pseudo header */ + skb_pull(ax_skb, 2); + skb_set_tail_pointer(ax_skb, ax_skb->len); ax_skb->truesize = pkt_len + sizeof(struct sk_buff); ax88179_rx_checksum(ax_skb, pkt_hdr); usbnet_skb_return(dev, ax_skb);