iwlwifi: pcie: don't consider IV len in A-MSDU

From gen2 PN is totally offloaded to hardware (also the space for the
IV isn't part of the skb).  As you can see in mvm/mac80211.c:3545, the
MAC for cipher types CCMP/GCMP doesn't set
IEEE80211_KEY_FLAG_PUT_IV_SPACE for gen2 NICs.

This causes all the AMSDU data to be corrupted with cipher enabled.
Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c

@@ -251,27 +251,23 @@ static int iwl_pcie_gen2_build_amsdu(struct iwl_trans *trans,
 	struct ieee80211_hdr *hdr = (void *)skb->data;
 	unsigned int snap_ip_tcp_hdrlen, ip_hdrlen, total_len, hdr_room;
 	unsigned int mss = skb_shinfo(skb)->gso_size;
-	u16 length, iv_len, amsdu_pad;
+	u16 length, amsdu_pad;
 	u8 *start_hdr;
 	struct iwl_tso_hdr_page *hdr_page;
 	struct page **page_ptr;
 	struct tso_t tso;
 
-	/* if the packet is protected, then it must be CCMP or GCMP */
-	iv_len = ieee80211_has_protected(hdr->frame_control) ?
-		IEEE80211_CCMP_HDR_LEN : 0;
-
 	trace_iwlwifi_dev_tx(trans->dev, skb, tfd, sizeof(*tfd),
 			     &dev_cmd->hdr, start_len, 0);
 
 	ip_hdrlen = skb_transport_header(skb) - skb_network_header(skb);
 	snap_ip_tcp_hdrlen = 8 + ip_hdrlen + tcp_hdrlen(skb);
-	total_len = skb->len - snap_ip_tcp_hdrlen - hdr_len - iv_len;
+	total_len = skb->len - snap_ip_tcp_hdrlen - hdr_len;
 	amsdu_pad = 0;
 
 	/* total amount of header we may need for this A-MSDU */
 	hdr_room = DIV_ROUND_UP(total_len, mss) *
-		(3 + snap_ip_tcp_hdrlen + sizeof(struct ethhdr)) + iv_len;
+		(3 + snap_ip_tcp_hdrlen + sizeof(struct ethhdr));
 
 	/* Our device supports 9 segments at most, it will fit in 1 page */
 	hdr_page = get_page_hdr(trans, hdr_room);
@@ -282,14 +278,12 @@ static int iwl_pcie_gen2_build_amsdu(struct iwl_trans *trans,
 	start_hdr = hdr_page->pos;
 	page_ptr = (void *)((u8 *)skb->cb + trans_pcie->page_offs);
 	*page_ptr = hdr_page->page;
-	memcpy(hdr_page->pos, skb->data + hdr_len, iv_len);
-	hdr_page->pos += iv_len;
 
 	/*
-	 * Pull the ieee80211 header + IV to be able to use TSO core,
+	 * Pull the ieee80211 header to be able to use TSO core,
 	 * we will restore it for the tx_status flow.
 	 */
-	skb_pull(skb, hdr_len + iv_len);
+	skb_pull(skb, hdr_len);
 
 	/*
 	 * Remove the length of all the headers that we don't actually
@@ -364,8 +358,8 @@ static int iwl_pcie_gen2_build_amsdu(struct iwl_trans *trans,
 		}
 	}
 
-	/* re -add the WiFi header and IV */
-	skb_push(skb, hdr_len + iv_len);
+	/* re -add the WiFi header */
+	skb_push(skb, hdr_len);
 
 	return 0;