[PATCH NEXT V3] rtlwifi: Fix endian error in extracting packet type

[PATCH NEXT V3] rtlwifi: Fix endian error in extracting packet type

[Larry Finger]

From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

All of the rtlwifi drivers have an error in the routine that tests if
the data is "special". If it is, the subsequant transmission will be
at the lowest rate to enhance reliability. The 16-bit quantity is
big-endian, but was being extracted in native CPU mode. One of the
effects of this bug is to inhibit association under some conditions
as the TX rate is too high.

Based on suggestions by Joe Perches, the entire routine is rewritten.

One of the local headers contained duplicates of some of the ETH_P_XXX
definitions. These are deleted.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: Stable <stable@vger.kernel.org> [2.6.38+]
---

V2 - Addresses comments by Ben Hutchings and Bjorn Mork.
V3 - Rewrite of rtl_is_special_data()

 drivers/net/wireless/rtlwifi/base.c |   15 ++++++---------
 drivers/net/wireless/rtlwifi/wifi.h |    6 +-----
 2 files changed, 7 insertions(+), 14 deletions(-)
Index: wireless-testing/drivers/net/wireless/rtlwifi/base.c
===================================================================
--- wireless-testing.orig/drivers/net/wireless/rtlwifi/base.c
+++ wireless-testing/drivers/net/wireless/rtlwifi/base.c
@@ -37,6 +37,7 @@
 
 #include <linux/ip.h>
 #include <linux/module.h>
+#include <linux/udp.h>
 
 /*
  *NOTICE!!!: This file will be very big, we should
@@ -1074,64 +1075,52 @@ u8 rtl_is_special_data(struct ieee80211_
 	if (!ieee80211_is_data(fc))
 		return false;
 
+	ip = (const struct iphdr *)(skb->data + mac_hdr_len +
+				    SNAP_SIZE + PROTOC_TYPE_SIZE);
+	ether_type = be16_to_cpup((__be16 *)
+				  (skb->data + mac_hdr_len + SNAP_SIZE));
+
+	switch (ether_type) {
+	case ETH_P_IP: {
+		struct udphdr *udp;
+		u16 src;
+		u16 dst;
+
+		if (ip->protocol != IPPROTO_UDP)
+			return false;
+		udp = (struct udphdr *)((u8 *)ip + (ip->ihl << 2));
+		src = be16_to_cpu(udp->source);
+		dst = be16_to_cpu(udp->dest);
+
+		/* If this case involves port 68 (UDP BOOTP client) connecting
+		 * with port 67 (UDP BOOTP server), then return true so that
+		 * the lowest speed is used.
+		 */
+		if (!((src == 68 && dst == 67) || (src == 67 && dst == 68)))
+			return false;
 
-	ip = (struct iphdr *)((u8 *) skb->data + mac_hdr_len +
-			      SNAP_SIZE + PROTOC_TYPE_SIZE);
-	ether_type = *(u16 *) ((u8 *) skb->data + mac_hdr_len + SNAP_SIZE);
-	/*	ether_type = ntohs(ether_type); */
-
-	if (ETH_P_IP == ether_type) {
-		if (IPPROTO_UDP == ip->protocol) {
-			struct udphdr *udp = (struct udphdr *)((u8 *) ip +
-							       (ip->ihl << 2));
-			if (((((u8 *) udp)[1] == 68) &&
-			     (((u8 *) udp)[3] == 67)) ||
-			    ((((u8 *) udp)[1] == 67) &&
-			     (((u8 *) udp)[3] == 68))) {
-				/*
-				 * 68 : UDP BOOTP client
-				 * 67 : UDP BOOTP server
-				 */
-				RT_TRACE(rtlpriv, (COMP_SEND | COMP_RECV),
-					 DBG_DMESG, "dhcp %s !!\n",
-					 is_tx ? "Tx" : "Rx");
-
-				if (is_tx) {
-					rtlpriv->enter_ps = false;
-					schedule_work(&rtlpriv->
-						      works.lps_change_work);
-					ppsc->last_delaylps_stamp_jiffies =
-					    jiffies;
-				}
-
-				return true;
-			}
-		}
-	} else if (ETH_P_ARP == ether_type) {
-		if (is_tx) {
-			rtlpriv->enter_ps = false;
-			schedule_work(&rtlpriv->works.lps_change_work);
-			ppsc->last_delaylps_stamp_jiffies = jiffies;
-		}
-
-		return true;
-	} else if (ETH_P_PAE == ether_type) {
+		RT_TRACE(rtlpriv, (COMP_SEND | COMP_RECV), DBG_DMESG,
+			 "dhcp %s !!\n", is_tx ? "Tx" : "Rx");
+		break;
+	}
+	case ETH_P_ARP:
+		break;
+	case ETH_P_PAE:
 		RT_TRACE(rtlpriv, (COMP_SEND | COMP_RECV), DBG_DMESG,
 			 "802.1X %s EAPOL pkt!!\n", is_tx ? "Tx" : "Rx");
-
-		if (is_tx) {
-			rtlpriv->enter_ps = false;
-			schedule_work(&rtlpriv->works.lps_change_work);
-			ppsc->last_delaylps_stamp_jiffies = jiffies;
-		}
-
-		return true;
-	} else if (ETH_P_IPV6 == ether_type) {
-		/* IPv6 */
-		return true;
+		break;
+	case ETH_P_IPV6:
+		/* TODO: Is this right? */
+		return false;
+	default:
+		return false;
 	}
-
-	return false;
+	if (is_tx) {
+		rtlpriv->enter_ps = false;
+		schedule_work(&rtlpriv->works.lps_change_work);
+		ppsc->last_delaylps_stamp_jiffies = jiffies;
+	}
+	return true;
 }
 EXPORT_SYMBOL_GPL(rtl_is_special_data);
 
Index: wireless-testing/drivers/net/wireless/rtlwifi/wifi.h
===================================================================
--- wireless-testing.orig/drivers/net/wireless/rtlwifi/wifi.h
+++ wireless-testing/drivers/net/wireless/rtlwifi/wifi.h
@@ -77,11 +77,7 @@
 #define RTL_SLOT_TIME_9				9
 #define RTL_SLOT_TIME_20			20
 
-/*related with tcp/ip. */
-/*if_ehther.h*/
-#define ETH_P_PAE		0x888E	/*Port Access Entity (IEEE 802.1X) */
-#define ETH_P_IP		0x0800	/*Internet Protocol packet */
-#define ETH_P_ARP		0x0806	/*Address Resolution packet */
+/*related to tcp/ip. */
 #define SNAP_SIZE		6
 #define PROTOC_TYPE_SIZE	2