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ie: Add ie_build_rsne

This commit is contained in:
Denis Kenzior 2015-02-03 21:45:14 -06:00
parent 51dfb02ade
commit fc60014d47
2 changed files with 167 additions and 0 deletions

166
src/ie.c
View File

@ -600,3 +600,169 @@ static bool ie_build_akm_suite(uint8_t *data,
return false;
}
/*
* Generate an RSNE IE based on the information found in info.
* The to array must be 256 bytes in size
*
* In theory it is possible to generate 257 byte IE RSNs (1 byte for IE Type,
* 1 byte for Length and 255 bytes of data) but we don't support this
* possibility.
*/
bool ie_build_rsne(const struct ie_rsn_info *info, uint8_t *to)
{
/* These are the only valid pairwise suites */
static enum ie_rsn_cipher_suite pairwise_suites[] = {
IE_RSN_CIPHER_SUITE_CCMP,
IE_RSN_CIPHER_SUITE_TKIP,
IE_RSN_CIPHER_SUITE_WEP104,
IE_RSN_CIPHER_SUITE_WEP40,
IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER,
};
unsigned int pos;
unsigned int i;
uint8_t *countptr;
uint16_t count;
enum ie_rsn_akm_suite akm_suite;
to[0] = IE_TYPE_RSN;
/* Version field, always 1 */
pos = 2;
l_put_le16(1, to + pos);
pos += 2;
/* Group Data Cipher Suite */
if (!ie_build_cipher_suite(to + pos, info->group_cipher))
return false;
pos += 4;
/* Save position for Pairwise Cipher Suite Count field */
countptr = to + pos;
pos += 2;
for (i = 0, count = 0; i < L_ARRAY_SIZE(pairwise_suites); i++) {
enum ie_rsn_cipher_suite suite = pairwise_suites[i];
if (!(info->pairwise_ciphers & suite))
continue;
if (pos + 4 > 242)
return false;
if (!ie_build_cipher_suite(to + pos, suite))
return false;
pos += 4;
count += 1;
}
l_put_le16(count, countptr);
/* Save position for AKM Suite Count field */
countptr = to + pos;
pos += 2;
akm_suite = IE_RSN_AKM_SUITE_8021X;
count = 0;
for (count = 0, akm_suite = IE_RSN_AKM_SUITE_8021X;
akm_suite <= IE_RSN_AKM_SUITE_FT_OVER_SAE_SHA256;
akm_suite <<= 1) {
if (!(info->akm_suites & akm_suite))
continue;
if (pos + 4 > 248)
return false;
if (!ie_build_akm_suite(to + pos, akm_suite))
return false;
pos += 4;
count += 1;
}
l_put_le16(count, countptr);
/* Bits 0 - 7 of RSNE Capabilities field */
to[pos] = 0;
if (info->preauthentication)
to[pos] |= 0x1;
if (info->no_pairwise)
to[pos] |= 0x2;
to[pos] |= info->ptksa_replay_counter << 2;
to[pos] |= info->gtksa_replay_counter << 4;
if (info->mfpr)
to[pos] |= 0x40;
if (info->mfpc)
to[pos] |= 0x80;
pos += 1;
/* Bits 8 - 15 of RSNE Capabilities field */
to[pos] = 0;
if (info->peerkey_enabled)
to[pos] |= 0x2;
if (info->spp_a_msdu_capable)
to[pos] |= 0x4;
if (info->spp_a_msdu_required)
to[pos] |= 0x8;
if (info->pbac)
to[pos] |= 0x10;
if (info->extended_key_id)
to[pos] |= 0x20;
pos += 1;
/* Short hand the generated RSNE if possible */
if (info->num_pmkids == 0) {
/* No Group Management Cipher Suite */
if (to[pos - 2] == 0 && to[pos - 1] == 0) {
pos -= 2;
goto done;
} else if (!info->mfpc)
goto done;
else if (info->group_management_cipher ==
IE_RSN_CIPHER_SUITE_BIP)
goto done;
}
/* PMKID Count */
l_put_le16(info->num_pmkids, to + pos);
pos += 2;
if (pos + info->num_pmkids * 16 > 252)
return false;
/* PMKID List */
memcpy(to + pos, info->pmkids, 16 * info->num_pmkids);
pos += 16 * info->num_pmkids;
if (!info->mfpc)
goto done;
if (info->group_management_cipher == IE_RSN_CIPHER_SUITE_BIP)
goto done;
/* Group Management Cipher Suite */
if (!ie_build_cipher_suite(to, info->group_management_cipher))
return false;
pos += 4;
done:
to[1] = pos - 2;
return true;
}

View File

@ -248,3 +248,4 @@ void ie_tlv_builder_finalize(struct ie_tlv_builder *builder,
int ie_parse_rsne(struct ie_tlv_iter *iter, struct ie_rsn_info *info);
int ie_parse_rsne_from_data(const uint8_t *data, size_t len,
struct ie_rsn_info *info);
bool ie_build_rsne(const struct ie_rsn_info *info, uint8_t *to);