wireless: move some utility functions from mac80211 to cfg80211

The patch moves some utility functions from mac80211 to cfg80211.
Because these functions are doing generic 802.11 operations so they
are not mac80211 specific. The moving allows some fullmac drivers
to be also benefit from these utility functions.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Samuel Ortiz <samuel.ortiz@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 305 insertions, 0 deletions

diff --git a/net/wireless/util.c b/net/wireless/util.c
index b94c860..d072bff 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -4,7 +4,9 @@
  * Copyright 2007-2009	Johannes Berg <johannes@sipsolutions.net>
  */
 #include <linux/bitops.h>
+#include <linux/etherdevice.h>
 #include <net/cfg80211.h>
+#include <net/ip.h>
 #include "core.h"
 
 struct ieee80211_rate *
@@ -198,3 +200,306 @@ int cfg80211_validate_key_settings(struct key_params *params, int key_idx,
 
 	return 0;
 }
+
+/* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
+/* Ethernet-II snap header (RFC1042 for most EtherTypes) */
+const unsigned char rfc1042_header[] __aligned(2) =
+	{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
+EXPORT_SYMBOL(rfc1042_header);
+
+/* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
+const unsigned char bridge_tunnel_header[] __aligned(2) =
+	{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
+EXPORT_SYMBOL(bridge_tunnel_header);
+
+unsigned int ieee80211_hdrlen(__le16 fc)
+{
+	unsigned int hdrlen = 24;
+
+	if (ieee80211_is_data(fc)) {
+		if (ieee80211_has_a4(fc))
+			hdrlen = 30;
+		if (ieee80211_is_data_qos(fc))
+			hdrlen += IEEE80211_QOS_CTL_LEN;
+		goto out;
+	}
+
+	if (ieee80211_is_ctl(fc)) {
+		/*
+		 * ACK and CTS are 10 bytes, all others 16. To see how
+		 * to get this condition consider
+		 *   subtype mask:   0b0000000011110000 (0x00F0)
+		 *   ACK subtype:    0b0000000011010000 (0x00D0)
+		 *   CTS subtype:    0b0000000011000000 (0x00C0)
+		 *   bits that matter:         ^^^      (0x00E0)
+		 *   value of those: 0b0000000011000000 (0x00C0)
+		 */
+		if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
+			hdrlen = 10;
+		else
+			hdrlen = 16;
+	}
+out:
+	return hdrlen;
+}
+EXPORT_SYMBOL(ieee80211_hdrlen);
+
+unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
+{
+	const struct ieee80211_hdr *hdr =
+			(const struct ieee80211_hdr *)skb->data;
+	unsigned int hdrlen;
+
+	if (unlikely(skb->len < 10))
+		return 0;
+	hdrlen = ieee80211_hdrlen(hdr->frame_control);
+	if (unlikely(hdrlen > skb->len))
+		return 0;
+	return hdrlen;
+}
+EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
+
+int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
+{
+	int ae = meshhdr->flags & MESH_FLAGS_AE;
+	/* 7.1.3.5a.2 */
+	switch (ae) {
+	case 0:
+		return 6;
+	case 1:
+		return 12;
+	case 2:
+		return 18;
+	case 3:
+		return 24;
+	default:
+		return 6;
+	}
+}
+
+int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
+			   enum nl80211_iftype iftype)
+{
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+	u16 hdrlen, ethertype;
+	u8 *payload;
+	u8 dst[ETH_ALEN];
+	u8 src[ETH_ALEN] __aligned(2);
+
+	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
+		return -1;
+
+	hdrlen = ieee80211_hdrlen(hdr->frame_control);
+
+	/* convert IEEE 802.11 header + possible LLC headers into Ethernet
+	 * header
+	 * IEEE 802.11 address fields:
+	 * ToDS FromDS Addr1 Addr2 Addr3 Addr4
+	 *   0     0   DA    SA    BSSID n/a
+	 *   0     1   DA    BSSID SA    n/a
+	 *   1     0   BSSID SA    DA    n/a
+	 *   1     1   RA    TA    DA    SA
+	 */
+	memcpy(dst, ieee80211_get_DA(hdr), ETH_ALEN);
+	memcpy(src, ieee80211_get_SA(hdr), ETH_ALEN);
+
+	switch (hdr->frame_control &
+		cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
+	case cpu_to_le16(IEEE80211_FCTL_TODS):
+		if (unlikely(iftype != NL80211_IFTYPE_AP &&
+			     iftype != NL80211_IFTYPE_AP_VLAN))
+			return -1;
+		break;
+	case cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
+		if (unlikely(iftype != NL80211_IFTYPE_WDS &&
+			     iftype != NL80211_IFTYPE_MESH_POINT))
+			return -1;
+		if (iftype == NL80211_IFTYPE_MESH_POINT) {
+			struct ieee80211s_hdr *meshdr =
+				(struct ieee80211s_hdr *) (skb->data + hdrlen);
+			hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
+			if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
+				memcpy(dst, meshdr->eaddr1, ETH_ALEN);
+				memcpy(src, meshdr->eaddr2, ETH_ALEN);
+			}
+		}
+		break;
+	case cpu_to_le16(IEEE80211_FCTL_FROMDS):
+		if (iftype != NL80211_IFTYPE_STATION ||
+		    (is_multicast_ether_addr(dst) &&
+		     !compare_ether_addr(src, addr)))
+			return -1;
+		break;
+	case cpu_to_le16(0):
+		if (iftype != NL80211_IFTYPE_ADHOC)
+			return -1;
+		break;
+	}
+
+	if (unlikely(skb->len - hdrlen < 8))
+		return -1;
+
+	payload = skb->data + hdrlen;
+	ethertype = (payload[6] << 8) | payload[7];
+
+	if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
+		    ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
+		   compare_ether_addr(payload, bridge_tunnel_header) == 0)) {
+		/* remove RFC1042 or Bridge-Tunnel encapsulation and
+		 * replace EtherType */
+		skb_pull(skb, hdrlen + 6);
+		memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN);
+		memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN);
+	} else {
+		struct ethhdr *ehdr;
+		__be16 len;
+
+		skb_pull(skb, hdrlen);
+		len = htons(skb->len);
+		ehdr = (struct ethhdr *) skb_push(skb, sizeof(struct ethhdr));
+		memcpy(ehdr->h_dest, dst, ETH_ALEN);
+		memcpy(ehdr->h_source, src, ETH_ALEN);
+		ehdr->h_proto = len;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(ieee80211_data_to_8023);
+
+int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
+			     enum nl80211_iftype iftype, u8 *bssid, bool qos)
+{
+	struct ieee80211_hdr hdr;
+	u16 hdrlen, ethertype;
+	__le16 fc;
+	const u8 *encaps_data;
+	int encaps_len, skip_header_bytes;
+	int nh_pos, h_pos;
+	int head_need;
+
+	if (unlikely(skb->len < ETH_HLEN))
+		return -EINVAL;
+
+	nh_pos = skb_network_header(skb) - skb->data;
+	h_pos = skb_transport_header(skb) - skb->data;
+
+	/* convert Ethernet header to proper 802.11 header (based on
+	 * operation mode) */
+	ethertype = (skb->data[12] << 8) | skb->data[13];
+	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
+
+	switch (iftype) {
+	case NL80211_IFTYPE_AP:
+	case NL80211_IFTYPE_AP_VLAN:
+		fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
+		/* DA BSSID SA */
+		memcpy(hdr.addr1, skb->data, ETH_ALEN);
+		memcpy(hdr.addr2, addr, ETH_ALEN);
+		memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
+		hdrlen = 24;
+		break;
+	case NL80211_IFTYPE_STATION:
+		fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
+		/* BSSID SA DA */
+		memcpy(hdr.addr1, bssid, ETH_ALEN);
+		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
+		memcpy(hdr.addr3, skb->data, ETH_ALEN);
+		hdrlen = 24;
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		/* DA SA BSSID */
+		memcpy(hdr.addr1, skb->data, ETH_ALEN);
+		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
+		memcpy(hdr.addr3, bssid, ETH_ALEN);
+		hdrlen = 24;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (qos) {
+		fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
+		hdrlen += 2;
+	}
+
+	hdr.frame_control = fc;
+	hdr.duration_id = 0;
+	hdr.seq_ctrl = 0;
+
+	skip_header_bytes = ETH_HLEN;
+	if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
+		encaps_data = bridge_tunnel_header;
+		encaps_len = sizeof(bridge_tunnel_header);
+		skip_header_bytes -= 2;
+	} else if (ethertype > 0x600) {
+		encaps_data = rfc1042_header;
+		encaps_len = sizeof(rfc1042_header);
+		skip_header_bytes -= 2;
+	} else {
+		encaps_data = NULL;
+		encaps_len = 0;
+	}
+
+	skb_pull(skb, skip_header_bytes);
+	nh_pos -= skip_header_bytes;
+	h_pos -= skip_header_bytes;
+
+	head_need = hdrlen + encaps_len - skb_headroom(skb);
+
+	if (head_need > 0 || skb_cloned(skb)) {
+		head_need = max(head_need, 0);
+		if (head_need)
+			skb_orphan(skb);
+
+		if (pskb_expand_head(skb, head_need, 0, GFP_ATOMIC)) {
+			printk(KERN_ERR "failed to reallocate Tx buffer\n");
+			return -ENOMEM;
+		}
+		skb->truesize += head_need;
+	}
+
+	if (encaps_data) {
+		memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
+		nh_pos += encaps_len;
+		h_pos += encaps_len;
+	}
+
+	memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
+
+	nh_pos += hdrlen;
+	h_pos += hdrlen;
+
+	/* Update skb pointers to various headers since this modified frame
+	 * is going to go through Linux networking code that may potentially
+	 * need things like pointer to IP header. */
+	skb_set_mac_header(skb, 0);
+	skb_set_network_header(skb, nh_pos);
+	skb_set_transport_header(skb, h_pos);
+
+	return 0;
+}
+EXPORT_SYMBOL(ieee80211_data_from_8023);
+
+/* Given a data frame determine the 802.1p/1d tag to use. */
+unsigned int cfg80211_classify8021d(struct sk_buff *skb)
+{
+	unsigned int dscp;
+
+	/* skb->priority values from 256->263 are magic values to
+	 * directly indicate a specific 802.1d priority.  This is used
+	 * to allow 802.1d priority to be passed directly in from VLAN
+	 * tags, etc.
+	 */
+	if (skb->priority >= 256 && skb->priority <= 263)
+		return skb->priority - 256;
+
+	switch (skb->protocol) {
+	case htons(ETH_P_IP):
+		dscp = ip_hdr(skb)->tos & 0xfc;
+		break;
+	default:
+		return 0;
+	}
+
+	return dscp >> 5;
+}
+EXPORT_SYMBOL(cfg80211_classify8021d);