NFC: digital: Rework ACK PDU handling in initiator mode

With this patch, ACK PDU sk_buffs are now freed and code has been
refactored for better errors handling.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index e0268777ab180ac8eee0a7d8f2c23c82a1b26aeb..03bfc74745f7192b87deb85f8a1a10523d38a460 100644 (file)
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -782,6 +782,12 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
                break;
 
        case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
+               if (DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) {
+                       PROTOCOL_ERR("14.12.4.5");
+                       rc = -EIO;
+                       goto exit;
+               }
+
                if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
                        PROTOCOL_ERR("14.12.3.3");
                        rc = -EIO;
@@ -791,22 +797,25 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
                ddev->curr_nfc_dep_pni =
                        DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);
 
-               if (ddev->chaining_skb && !DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) {
-                       kfree_skb(ddev->saved_skb);
-                       ddev->saved_skb = NULL;
+               if (!ddev->chaining_skb) {
+                       PROTOCOL_ERR("14.12.4.3");
+                       rc = -EIO;
+                       goto exit;
+               }
 
-                       rc = digital_in_send_dep_req(ddev, NULL,
-                                                    ddev->chaining_skb,
-                                                    ddev->data_exch);
-                       if (rc)
-                               goto error;
+               /* The initiator has received a valid ACK. Free the last sent
+                * PDU and keep on sending chained skb.
+                */
+               kfree_skb(ddev->saved_skb);
+               ddev->saved_skb = NULL;
 
-                       return;
-               }
+               rc = digital_in_send_dep_req(ddev, NULL,
+                                            ddev->chaining_skb,
+                                            ddev->data_exch);
+               if (rc)
+                       goto error;
 
-               pr_err("Received a ACK/NACK PDU\n");
-               rc = -EINVAL;
-               goto exit;
+               goto free_resp;
 
        case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
                if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) { /* ATN */
@@ -839,6 +848,11 @@ error:
 
        if (rc)
                kfree_skb(resp);
+
+       return;
+
+free_resp:
+       dev_kfree_skb(resp);
 }
 
 int digital_in_send_dep_req(struct nfc_digital_dev *ddev,