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authorJohannes Berg <johannes@sipsolutions.net>2005-12-31 11:35:20 +0100
committerJeff Garzik <jgarzik@pobox.com>2006-01-09 10:34:25 -0500
commita4bf26f30e398afa293b85103c885f03d4660a07 (patch)
treeba3db16dc30725c1c1009831b9a29de00d3fd238 /net/ieee80211/ieee80211_crypt_wep.c
parentdf22b8aaba3f41cc61f57f5ead78be45edcb7db5 (diff)
[PATCH] ieee80211: enable hw wep where host has to build IV
This patch fixes some of the ieee80211 crypto related code so that instead of having the host fully do crypto operations, the host_build_iv flag works properly (for WEP in this patch) which, if turned on, requires the hardware to do all crypto operations, but the ieee80211 layer builds the IV. The hardware also has to build the ICV. Previously, the host_build_iv flag couldn't be used at all for WEP, and not alone (with both host_decrypt and host_encrypt disabled) because the crypto algorithm wasn't assigned. This is also fixed. I have tested this patch both in host crypto mode and in hw crypto mode (with the Broadcom chipset). [resent, signing digitally caused it to be MIME-junked, sorry] Signed-Off-By: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'net/ieee80211/ieee80211_crypt_wep.c')
-rw-r--r--net/ieee80211/ieee80211_crypt_wep.c61
1 files changed, 43 insertions, 18 deletions
diff --git a/net/ieee80211/ieee80211_crypt_wep.c b/net/ieee80211/ieee80211_crypt_wep.c
index 073aebdf0f6..f8dca31be5d 100644
--- a/net/ieee80211/ieee80211_crypt_wep.c
+++ b/net/ieee80211/ieee80211_crypt_wep.c
@@ -75,22 +75,14 @@ static void prism2_wep_deinit(void *priv)
kfree(priv);
}
-/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
- * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
- * so the payload length increases with 8 bytes.
- *
- * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
- */
-static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
+/* Add WEP IV/key info to a frame that has at least 4 bytes of headroom */
+static int prism2_wep_build_iv(struct sk_buff *skb, int hdr_len, void *priv)
{
struct prism2_wep_data *wep = priv;
- u32 crc, klen, len;
- u8 key[WEP_KEY_LEN + 3];
- u8 *pos, *icv;
- struct scatterlist sg;
-
- if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
- skb->len < hdr_len)
+ u32 klen, len;
+ u8 *pos;
+
+ if (skb_headroom(skb) < 4 || skb->len < hdr_len)
return -1;
len = skb->len - hdr_len;
@@ -112,15 +104,47 @@ static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
}
/* Prepend 24-bit IV to RC4 key and TX frame */
- *pos++ = key[0] = (wep->iv >> 16) & 0xff;
- *pos++ = key[1] = (wep->iv >> 8) & 0xff;
- *pos++ = key[2] = wep->iv & 0xff;
+ *pos++ = (wep->iv >> 16) & 0xff;
+ *pos++ = (wep->iv >> 8) & 0xff;
+ *pos++ = wep->iv & 0xff;
*pos++ = wep->key_idx << 6;
+ return 0;
+}
+
+/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
+ * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
+ * so the payload length increases with 8 bytes.
+ *
+ * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
+ */
+static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
+{
+ struct prism2_wep_data *wep = priv;
+ u32 crc, klen, len;
+ u8 *pos, *icv;
+ struct scatterlist sg;
+ u8 key[WEP_KEY_LEN + 3];
+
+ /* other checks are in prism2_wep_build_iv */
+ if (skb_tailroom(skb) < 4)
+ return -1;
+
+ /* add the IV to the frame */
+ if (prism2_wep_build_iv(skb, hdr_len, priv))
+ return -1;
+
+ /* Copy the IV into the first 3 bytes of the key */
+ memcpy(key, skb->data + hdr_len, 3);
+
/* Copy rest of the WEP key (the secret part) */
memcpy(key + 3, wep->key, wep->key_len);
+
+ len = skb->len - hdr_len - 4;
+ pos = skb->data + hdr_len + 4;
+ klen = 3 + wep->key_len;
- /* Append little-endian CRC32 and encrypt it to produce ICV */
+ /* Append little-endian CRC32 over only the data and encrypt it to produce ICV */
crc = ~crc32_le(~0, pos, len);
icv = skb_put(skb, 4);
icv[0] = crc;
@@ -231,6 +255,7 @@ static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
.name = "WEP",
.init = prism2_wep_init,
.deinit = prism2_wep_deinit,
+ .build_iv = prism2_wep_build_iv,
.encrypt_mpdu = prism2_wep_encrypt,
.decrypt_mpdu = prism2_wep_decrypt,
.encrypt_msdu = NULL,