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authorMark A. Greer <mgreer@animalcreek.com>2014-09-23 16:38:12 -0700
committerSamuel Ortiz <sameo@linux.intel.com>2014-11-28 12:39:47 +0100
commit49dbb14e30c3249f98fe243c3e21b91d10c5c59b (patch)
tree1d98889745d1c4d6ebf9150ef68a47dc762a693b /net/nfc
parenta80509c76bf2b10dae76f3caea343ac4b85c72b4 (diff)
NFC: digital: Add NFC-DEP Target-side NACK Support
When an NFC-DEP Target receives a NACK PDU with a PNI equal to 1 less than the current PNI, it is supposed to re-send the last PDU. This is implied in section 14.12.5.4 of the NFC Digital Protocol Spec. The digital layer's NFC-DEP code doesn't implement Target-side NACK handing so add it. The last PDU that was sent is saved in the 'nfc_digital_dev' structure's 'saved_skb' member. The skb will have an additional reference taken to ensure that the skb isn't freed when the driver performs a kfree_skb() on the skb. The length of the skb/PDU is also saved so the length can be restored when re-sending the PDU in the skb (the driver will perform an skb_pull() so an skb_push() needs to be done to restore the skb's data pointer/length). Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com> Tested-by: Thierry Escande <thierry.escande@linux.intel.com> Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'net/nfc')
-rw-r--r--net/nfc/digital_dep.c62
1 files changed, 51 insertions, 11 deletions
diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index 9840e858ec5b..31418edbe78e 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -864,14 +864,29 @@ static int digital_tg_send_ack(struct nfc_digital_dev *ddev,
ddev->skb_add_crc(skb);
+ ddev->saved_skb = skb_get(skb);
+ ddev->saved_skb_len = skb->len;
+
rc = digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
data_exch);
- if (rc)
+ if (rc) {
kfree_skb(skb);
+ kfree_skb(ddev->saved_skb);
+ ddev->saved_skb = NULL;
+ }
return rc;
}
+static int digital_tg_send_saved_skb(struct nfc_digital_dev *ddev)
+{
+ skb_get(ddev->saved_skb);
+ skb_push(ddev->saved_skb, ddev->saved_skb_len);
+
+ return digital_tg_send_cmd(ddev, ddev->saved_skb, 1500,
+ digital_tg_recv_dep_req, NULL);
+}
+
static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
struct sk_buff *resp)
{
@@ -948,6 +963,9 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
goto exit;
}
+ kfree_skb(ddev->saved_skb);
+ ddev->saved_skb = NULL;
+
resp = digital_recv_dep_data_gather(ddev, pfb, resp,
digital_tg_send_ack, NULL);
if (IS_ERR(resp)) {
@@ -966,23 +984,36 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
rc = 0;
break;
case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
- if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
- PROTOCOL_ERR("14.12.3.4");
- rc = -EIO;
- goto exit;
- }
+ if (!DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) { /* ACK */
+ if ((DIGITAL_NFC_DEP_PFB_PNI(pfb) !=
+ ddev->curr_nfc_dep_pni) ||
+ !ddev->chaining_skb || !ddev->saved_skb) {
+ rc = -EIO;
+ goto exit;
+ }
+
+ kfree_skb(ddev->saved_skb);
+ ddev->saved_skb = NULL;
- if (ddev->chaining_skb && !DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) {
rc = digital_tg_send_dep_res(ddev, ddev->chaining_skb);
if (rc)
goto exit;
+ } else { /* NACK */
+ if ((DIGITAL_NFC_DEP_PFB_PNI(pfb + 1) !=
+ ddev->curr_nfc_dep_pni) ||
+ !ddev->saved_skb) {
+ rc = -EIO;
+ goto exit;
+ }
- return;
+ rc = digital_tg_send_saved_skb(ddev);
+ if (rc) {
+ kfree_skb(ddev->saved_skb);
+ goto exit;
+ }
}
- pr_err("Received a ACK/NACK PDU\n");
- rc = -EINVAL;
- goto exit;
+ return;
case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
pr_err("Received a SUPERVISOR PDU\n");
rc = -EINVAL;
@@ -995,6 +1026,9 @@ exit:
kfree_skb(ddev->chaining_skb);
ddev->chaining_skb = NULL;
+ kfree_skb(ddev->saved_skb);
+ ddev->saved_skb = NULL;
+
if (rc)
kfree_skb(resp);
}
@@ -1033,6 +1067,9 @@ int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb)
ddev->skb_add_crc(tmp_skb);
+ ddev->saved_skb = skb_get(tmp_skb);
+ ddev->saved_skb_len = tmp_skb->len;
+
rc = digital_tg_send_cmd(ddev, tmp_skb, 1500, digital_tg_recv_dep_req,
NULL);
if (rc) {
@@ -1041,6 +1078,9 @@ int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb)
kfree_skb(chaining_skb);
ddev->chaining_skb = NULL;
+
+ kfree_skb(ddev->saved_skb);
+ ddev->saved_skb = NULL;
}
return rc;