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ap: Implement Reassociation

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Add some form of the Reassociation procedure with comment on the
interpretation choice.
This commit is contained in:
Andrew Zaborowski 2017-09-30 04:28:12 +02:00 committed by Denis Kenzior
parent a26ca0fb66
commit 375e2262f2
1 changed files with 180 additions and 65 deletions
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245
src/ap.c
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@ -706,12 +706,13 @@ static uint32_t ap_send_mgmt_frame(struct ap_state *ap,
return id;
}
static void ap_new_sta_cb(struct l_genl_msg *msg, void *user_data)
static void ap_associate_sta_cb(struct l_genl_msg *msg, void *user_data)
{
struct sta_state *sta = user_data;
if (l_genl_msg_get_error(msg) < 0) {
l_error("NEW_STATION failed: %i", l_genl_msg_get_error(msg));
l_error("NEW_STATION/SET_STATION failed: %i",
l_genl_msg_get_error(msg));
return;
}
@ -738,6 +739,10 @@ static void ap_associate_sta(struct ap_state *ap, struct sta_state *sta)
uint8_t rates[256];
uint32_t r, minr, maxr, count = 0;
uint16_t capability = l_get_le16(&sta->capability);
uint8_t cmd = NL80211_CMD_NEW_STATION;
if (sta->associated)
cmd = NL80211_CMD_SET_STATION;
sta->associated = true;
sta->rsna = false;
@ -750,7 +755,7 @@ static void ap_associate_sta(struct ap_state *ap, struct sta_state *sta)
if (l_uintset_contains(sta->rates, r))
rates[count++] = r;
msg = l_genl_msg_new_sized(NL80211_CMD_NEW_STATION, 300);
msg = l_genl_msg_new_sized(cmd, 300);
l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &ifindex);
l_genl_msg_append_attr(msg, NL80211_ATTR_MAC, 6, sta->addr);
l_genl_msg_append_attr(msg, NL80211_ATTR_STA_AID, 2, &sta->aid);
@ -762,9 +767,12 @@ static void ap_associate_sta(struct ap_state *ap, struct sta_state *sta)
l_genl_msg_append_attr(msg, NL80211_ATTR_STA_CAPABILITY, 2,
&capability);
if (!l_genl_family_send(nl80211, msg, ap_new_sta_cb, sta, NULL)) {
if (!l_genl_family_send(nl80211, msg, ap_associate_sta_cb, sta, NULL)) {
l_genl_msg_unref(msg);
l_error("Issuing NEW_STATION failed");
if (cmd == NL80211_CMD_NEW_STATION)
l_error("Issuing NEW_STATION failed");
else
l_error("Issuing SET_STATION failed");
}
}
@ -812,7 +820,7 @@ static void ap_success_assoc_resp_cb(struct l_genl_msg *msg, void *user_data)
sta->assoc_resp_cmd_id = 0;
if (l_genl_msg_get_error(msg) < 0) {
l_error("AP Association Response not sent or not ACKed: %i",
l_error("AP (Re)Association Response not sent or not ACKed: %i",
l_genl_msg_get_error(msg));
/* If we were in State 3 or 4 go to back to State 2 */
@ -822,31 +830,26 @@ static void ap_success_assoc_resp_cb(struct l_genl_msg *msg, void *user_data)
return;
}
/* If we were in State 4, go to back to State 3 */
if (sta->rsna)
ap_drop_rsna(ap, sta);
/* If we were in State 2, 3 or 4 also go to State 3 */
ap_associate_sta(ap, sta);
/* If we were in State 2 also go to State 3 */
if (!sta->associated)
ap_associate_sta(ap, sta);
l_info("AP Association Response ACK received");
l_info("AP (Re)Association Response ACK received");
}
static void ap_fail_assoc_resp_cb(struct l_genl_msg *msg, void *user_data)
{
if (l_genl_msg_get_error(msg) < 0)
l_error("AP Association Response with an error status not "
l_error("AP (Re)Association Response with an error status not "
"sent or not ACKed: %i", l_genl_msg_get_error(msg));
else
l_info("AP Association Response with an errror status "
l_info("AP (Re)Association Response with an errror status "
"delivered OK");
}
static uint32_t ap_assoc_resp(struct ap_state *ap, struct sta_state *sta,
const uint8_t *dest, uint16_t aid,
enum mmpdu_reason_code status_code,
l_genl_msg_func_t callback)
bool reassoc, l_genl_msg_func_t callback)
{
const uint8_t *addr = device_get_address(ap->device);
uint8_t mpdu_buf[128];
@ -861,7 +864,9 @@ static uint32_t ap_assoc_resp(struct ap_state *ap, struct sta_state *sta,
/* Header */
mpdu->fc.protocol_version = 0;
mpdu->fc.type = MPDU_TYPE_MANAGEMENT;
mpdu->fc.subtype = MPDU_MANAGEMENT_SUBTYPE_ASSOCIATION_RESPONSE;
mpdu->fc.subtype = reassoc ?
MPDU_MANAGEMENT_SUBTYPE_REASSOCIATION_RESPONSE :
MPDU_MANAGEMENT_SUBTYPE_ASSOCIATION_RESPONSE;
memcpy(mpdu->address_1, dest, 6); /* DA */
memcpy(mpdu->address_2, addr, 6); /* SA */
memcpy(mpdu->address_3, addr, 6); /* BSSID */
@ -896,53 +901,78 @@ static uint32_t ap_assoc_resp(struct ap_state *ap, struct sta_state *sta,
true, callback, sta);
}
/* 802.11-2016 9.3.3.6 (frame format), 802.11-2016 11.3.5.3 (MLME/SME) */
static void ap_assoc_req_cb(struct netdev *netdev,
const struct mmpdu_header *hdr,
const void *body, size_t body_len,
void *user_data)
/*
* This handles both the Association and Reassociation Request frames.
* Association Request is documented in 802.11-2016 9.3.3.6 (frame format),
* 802.11-2016 11.3.5.3 (MLME/SME) and Reassociation in 802.11-2016
* 9.3.3.8 (frame format), 802.11-2016 11.3.5.3 (MLME/SME).
*
* The difference between Association and Reassociation procedures is
* documented in 11.3.5.1 "General" but seems inconsistent with specific
* instructions in 11.3.5.3 vs. 11.3.5.5 and 11.3.5.2 vs. 11.3.5.4.
* According to 11.3.5.1:
* 1. Reassociation requires the STA to be already associated in the ESS,
* Association doesn't.
* 2. Unsuccessful Reassociation should not cause a state transition of
* the authentication state between the two STAs.
*
* The first requirement is not present in 11.3.5.5 which is virtually
* identical with 11.3.5.3, but we do implement it. Number 2 is also not
* reflected in 11.3.5.5 where the state transitions are the same as in
* 11.3.5.3 and 11.3.5.4 where the state transitions are the same as in
* 11.3.5.2 including f) "If a Reassociation Response frame is received
* with a status code other than SUCCESS [...] 1. [...] the state for
* the AP [...] shall be set to State 2 [...]"
*
* For the record here are the apparent differences between 802.11-2016
* 11.3.5.2 and 11.3.5.4 ignoring the s/Associate/Reassociate/ changes
* and the special case of Reassociation during a Fast Transition.
* o Points c) and d) are switched around.
* o On success, the STA is disassociated from all other APs in 11.3.5.2,
* and from the previous AP in 11.3.5.4 c). (Shouldn't make a
* difference as there seems to be no way for the STA to become
* associated with more than one AP)
* o After Association a 4-Way Handshake is always performed, after
* Reassociation it is only performed if STA was in State 3 according
* to 11.3.5.4 g). This is not reflected in 11.3.5.5 though.
* Additionally 11.3.5.4 and 11.3.5.5 require the STA and AP
* respectively to delete current PTKSA/GTKSA/IGTKSA at the beginning
* of the procedure independent of the STA state so without a 4-Way
* Handshake the two stations end up with no encryption keys.
*
* The main difference between 11.3.5.3 and 11.3.5.5 is presence of p).
*/
static void ap_assoc_reassoc(struct sta_state *sta, bool reassoc,
const struct mmpdu_field_capability *capability,
uint16_t listen_interval,
struct ie_tlv_iter *ies)
{
struct ap_state *ap = user_data;
struct sta_state *sta;
const uint8_t *from = hdr->address_2;
const struct mmpdu_association_request *req = body;
struct ie_tlv_iter iter;
struct ap_state *ap = sta->ap;
const char *ssid = NULL;
const uint8_t *rsn = NULL;
size_t ssid_len = 0, rsn_len = 0;
struct l_uintset *rates = NULL;
struct ie_rsn_info rsn_info;
const uint8_t *bssid = device_get_address(ap->device);
int err;
l_info("AP Association Request from %s", util_address_to_string(from));
if (memcmp(hdr->address_1, bssid, 6) ||
memcmp(hdr->address_3, bssid, 6))
return;
sta = l_queue_find(ap->sta_states, ap_sta_match_addr, from);
if (!sta) {
err = MMPDU_REASON_CODE_STA_REQ_ASSOC_WITHOUT_AUTH;
goto bad_frame;
}
if (sta->assoc_resp_cmd_id)
return;
ie_tlv_iter_init(&iter, req->ies, body_len - sizeof(*req));
if (reassoc && !sta->associated) {
err = MMPDU_REASON_CODE_CLASS3_FRAME_FROM_NONASSOC_STA;
goto unsupported;
}
while (ie_tlv_iter_next(&iter))
switch (ie_tlv_iter_get_tag(&iter)) {
while (ie_tlv_iter_next(ies))
switch (ie_tlv_iter_get_tag(ies)) {
case IE_TYPE_SSID:
ssid = (const char *) ie_tlv_iter_get_data(&iter);
ssid_len = ie_tlv_iter_get_length(&iter);
ssid = (const char *) ie_tlv_iter_get_data(ies);
ssid_len = ie_tlv_iter_get_length(ies);
break;
case IE_TYPE_SUPPORTED_RATES:
case IE_TYPE_EXTENDED_SUPPORTED_RATES:
if (ie_parse_supported_rates(&iter, &rates) < 0) {
if (ie_parse_supported_rates(ies, &rates) < 0) {
err = MMPDU_REASON_CODE_INVALID_IE;
goto bad_frame;
}
@ -950,13 +980,13 @@ static void ap_assoc_req_cb(struct netdev *netdev,
break;
case IE_TYPE_RSN:
if (ie_parse_rsne(&iter, &rsn_info) < 0) {
if (ie_parse_rsne(ies, &rsn_info) < 0) {
err = MMPDU_REASON_CODE_INVALID_IE;
goto bad_frame;
}
rsn = (const uint8_t *) ie_tlv_iter_get_data(&iter);
rsn_len = ie_tlv_iter_get_length(&iter);
rsn = (const uint8_t *) ie_tlv_iter_get_data(ies);
rsn_len = ie_tlv_iter_get_length(ies);
break;
}
@ -977,25 +1007,27 @@ static void ap_assoc_req_cb(struct netdev *netdev,
}
if (!(rsn_info.pairwise_ciphers & ap->ciphers)) {
err = MMPDU_REASON_CODE_UNSPECIFIED;
err = MMPDU_REASON_CODE_INVALID_PAIRWISE_CIPHER;
goto unsupported;
}
if (rsn_info.akm_suites != IE_RSN_AKM_SUITE_PSK) {
err = MMPDU_REASON_CODE_UNSPECIFIED;
err = MMPDU_REASON_CODE_INVALID_AKMP;
goto unsupported;
}
/*
* Everything fine so far, assign an AID, send response. According
* to 802.11-2016 11.3.5.3 l) we will only go to State 3
* (set sta->associated) once we receive the station's ACK or gave
* up on resends.
*/
sta->aid = ++ap->last_aid;
if (!sta->associated) {
/*
* Everything fine so far, assign an AID, send response.
* According to 802.11-2016 11.3.5.3 l) we will only go to
* State 3 (set sta->associated) once we receive the station's
* ACK or gave up on resends.
*/
sta->aid = ++ap->last_aid;
}
sta->capability = req->capability;
sta->listen_interval = L_LE16_TO_CPU(req->listen_interval);
sta->capability = *capability;
sta->listen_interval = listen_interval;
if (sta->rates)
l_uintset_free(sta->rates);
@ -1013,9 +1045,10 @@ static void ap_assoc_req_cb(struct netdev *netdev,
ap_drop_rsna(ap, sta);
sta->assoc_resp_cmd_id = ap_assoc_resp(ap, sta, sta->addr, sta->aid, 0,
reassoc,
ap_success_assoc_resp_cb);
if (!sta->assoc_resp_cmd_id)
l_error("Sending success Association Response failed");
l_error("Sending success (Re)Association Response failed");
return;
@ -1039,8 +1072,85 @@ bad_frame:
if (rates)
l_uintset_free(rates);
if (!ap_assoc_resp(ap, NULL, from, 0, err, ap_fail_assoc_resp_cb))
l_error("Sending error Association Response failed");
if (!ap_assoc_resp(ap, NULL, sta->addr, 0, err, reassoc,
ap_fail_assoc_resp_cb))
l_error("Sending error (Re)Association Response failed");
}
/* 802.11-2016 9.3.3.6 */
static void ap_assoc_req_cb(struct netdev *netdev,
const struct mmpdu_header *hdr,
const void *body, size_t body_len,
void *user_data)
{
struct ap_state *ap = user_data;
struct sta_state *sta;
const uint8_t *from = hdr->address_2;
const struct mmpdu_association_request *req = body;
const uint8_t *bssid = device_get_address(ap->device);
struct ie_tlv_iter iter;
l_info("AP Association Request from %s", util_address_to_string(from));
if (memcmp(hdr->address_1, bssid, 6) ||
memcmp(hdr->address_3, bssid, 6))
return;
sta = l_queue_find(ap->sta_states, ap_sta_match_addr, from);
if (!sta) {
if (!ap_assoc_resp(ap, NULL, from, 0,
MMPDU_REASON_CODE_STA_REQ_ASSOC_WITHOUT_AUTH,
false, ap_fail_assoc_resp_cb))
l_error("Sending error Association Response failed");
return;
}
ie_tlv_iter_init(&iter, req->ies, body_len - sizeof(*req));
ap_assoc_reassoc(sta, false, &req->capability,
L_LE16_TO_CPU(req->listen_interval), &iter);
}
/* 802.11-2016 9.3.3.8 */
static void ap_reassoc_req_cb(struct netdev *netdev,
const struct mmpdu_header *hdr,
const void *body, size_t body_len,
void *user_data)
{
struct ap_state *ap = user_data;
struct sta_state *sta;
const uint8_t *from = hdr->address_2;
const struct mmpdu_reassociation_request *req = body;
const uint8_t *bssid = device_get_address(ap->device);
struct ie_tlv_iter iter;
int err;
l_info("AP Reassociation Request from %s",
util_address_to_string(from));
if (memcmp(hdr->address_1, bssid, 6) ||
memcmp(hdr->address_3, bssid, 6))
return;
sta = l_queue_find(ap->sta_states, ap_sta_match_addr, from);
if (!sta) {
err = MMPDU_REASON_CODE_STA_REQ_ASSOC_WITHOUT_AUTH;
goto bad_frame;
}
if (memcmp(req->current_ap_address, bssid, 6)) {
err = MMPDU_REASON_CODE_UNSPECIFIED;
goto bad_frame;
}
ie_tlv_iter_init(&iter, req->ies, body_len - sizeof(*req));
ap_assoc_reassoc(sta, true, &req->capability,
L_LE16_TO_CPU(req->listen_interval), &iter);
return;
bad_frame:
if (!ap_assoc_resp(ap, NULL, from, 0, err, true, ap_fail_assoc_resp_cb))
l_error("Sending error Reassociation Response failed");
}
static void ap_probe_resp_cb(struct l_genl_msg *msg, void *user_data)
@ -1468,6 +1578,11 @@ int ap_start(struct device *device, const char *ssid, const char *psk,
NULL, 0, ap_assoc_req_cb, ap);
l_queue_push_tail(ap->frame_watch_ids, L_UINT_TO_PTR(id));
id = netdev_frame_watch_add(netdev, 0x0000 |
(MPDU_MANAGEMENT_SUBTYPE_REASSOCIATION_REQUEST << 4),
NULL, 0, ap_reassoc_req_cb, ap);
l_queue_push_tail(ap->frame_watch_ids, L_UINT_TO_PTR(id));
id = netdev_frame_watch_add(netdev, 0x0000 |
(MPDU_MANAGEMENT_SUBTYPE_PROBE_REQUEST << 4),
NULL, 0, ap_probe_req_cb, ap);