unsigned int ieee80211_get_hdrlen(FAR const struct ieee80211_frame *wh)
{
unsigned int size = sizeof(*wh);
/* NB: does not work with control frames */
DEBUGASSERT(ieee80211_has_seq(wh));
if (ieee80211_has_addr4(wh))
{
size += IEEE80211_ADDR_LEN; /* i_addr4 */
}
if (ieee80211_has_qos(wh))
{
size += sizeof(uint16_t); /* i_qos */
}
if (ieee80211_has_htc(wh))
{
size += sizeof(uint32_t); /* i_ht */
}
return size;
}
/*-
* Counter with CBC-MAC (CCM) - see RFC3610.
* CCMP uses the following CCM parameters: M = 8, L = 2
*/
static void
ieee80211_ccmp_phase1(rijndael_ctx *ctx, const struct ieee80211_frame *wh,
u_int64_t pn, int lm, u_int8_t b[16], u_int8_t a[16], u_int8_t s0[16])
{
u_int8_t auth[32], nonce[13];
u_int8_t *aad;
u_int8_t tid = 0;
int la, i;
/* construct AAD (additional authenticated data) */
aad = &auth[2]; /* skip l(a), will be filled later */
*aad = wh->i_fc[0];
/* 11w: conditionnally mask subtype field */
if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) ==
IEEE80211_FC0_TYPE_DATA)
*aad &= ~IEEE80211_FC0_SUBTYPE_MASK;
aad++;
/* protected bit is already set in wh */
*aad = wh->i_fc[1];
*aad &= ~(IEEE80211_FC1_RETRY | IEEE80211_FC1_PWR_MGT |
IEEE80211_FC1_MORE_DATA);
/* 11n: conditionnally mask order bit */
if (ieee80211_has_htc(wh))
*aad &= ~IEEE80211_FC1_ORDER;
aad++;
IEEE80211_ADDR_COPY(aad, wh->i_addr1); aad += IEEE80211_ADDR_LEN;
IEEE80211_ADDR_COPY(aad, wh->i_addr2); aad += IEEE80211_ADDR_LEN;
IEEE80211_ADDR_COPY(aad, wh->i_addr3); aad += IEEE80211_ADDR_LEN;
*aad++ = wh->i_seq[0] & ~0xf0;
*aad++ = 0;
if (ieee80211_has_addr4(wh)) {
IEEE80211_ADDR_COPY(aad,
((const struct ieee80211_frame_addr4 *)wh)->i_addr4);
aad += IEEE80211_ADDR_LEN;
}
if (ieee80211_has_qos(wh)) {
*aad++ = tid = ieee80211_get_qos(wh) & IEEE80211_QOS_TID;
*aad++ = 0;
}
/* construct CCM nonce */
nonce[ 0] = tid;
if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) ==
IEEE80211_FC0_TYPE_MGT)
nonce[0] |= 1 << 4; /* 11w: set management bit */
IEEE80211_ADDR_COPY(&nonce[1], wh->i_addr2);
nonce[ 7] = pn >> 40; /* PN5 */
nonce[ 8] = pn >> 32; /* PN4 */
nonce[ 9] = pn >> 24; /* PN3 */
nonce[10] = pn >> 16; /* PN2 */
nonce[11] = pn >> 8; /* PN1 */
nonce[12] = pn; /* PN0 */
/* add 2 authentication blocks (including l(a) and padded AAD) */
la = aad - &auth[2]; /* fill l(a) */
auth[0] = la >> 8;
auth[1] = la & 0xff;
memset(aad, 0, 30 - la); /* pad AAD with zeros */
/* construct first block B_0 */
b[ 0] = 89; /* Flags = 64*Adata + 8*((M-2)/2) + (L-1) */
memcpy(&b[1], nonce, 13);
b[14] = lm >> 8;
b[15] = lm & 0xff;
rijndael_encrypt(ctx, b, b);
for (i = 0; i < 16; i++)
b[i] ^= auth[i];
rijndael_encrypt(ctx, b, b);
for (i = 0; i < 16; i++)
b[i] ^= auth[16 + i];
rijndael_encrypt(ctx, b, b);
/* construct S_0 */
a[ 0] = 1; /* Flags = L' = (L-1) */
memcpy(&a[1], nonce, 13);
a[14] = a[15] = 0;
rijndael_encrypt(ctx, a, s0);
}
