Chapter 4 Part 8 关联处理源码走读

最新推荐文章于 2024-09-14 10:10:22 发布

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最新推荐文章于 2024-09-14 10:10:22 发布 · 914 阅读

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CC 4.0 BY-SA版权

本文详细解析了WPAS中driverwrapper处理NL80211_CMD_CONNECT和NL80211_CMD_ROAM事件的过程，涉及连接成功与失败的响应、SSID设置、关键参数传递及后续的身份验证和加密流程，重点介绍了4-Way Handshake和Group Key Handshake的准备阶段。

关联事件处理流程分析

WPAS中的driver wrapper将收到来自wlan driver的 NL80211_CMD_CONNECT 命令

case NL80211_CMD_CONNECT:
case NL80211_CMD_ROAM:
    /*
      调用mlme_event_connect进行处理
      NL80211_ATTR_STATUS_CODE 保存AP的处理结果
      NL80211_ATTR_REQ_IE 保存Association Request请求时包含的IE
      NL80211_ATTR_RESP_IE 保存Association Response请求时包含的IE
     */
    mlme_event_connect(drv, cmd,
                tb[NL80211_ATTR_STATUS_CODE],
                tb[NL80211_ATTR_MAC],
                tb[NL80211_ATTR_REQ_IE],
                tb[NL80211_ATTR_RESP_IE],
                tb[NL80211_ATTR_TIMED_OUT],
                tb[NL80211_ATTR_TIMEOUT_REASON],
                NULL, NULL, NULL,
                tb[NL80211_ATTR_FILS_KEK],
                NULL,
                tb[NL80211_ATTR_FILS_ERP_NEXT_SEQ_NUM],
                tb[NL80211_ATTR_PMK],
                tb[NL80211_ATTR_PMKID]);
    break;



static void mlme_event_connect(struct wpa_driver_nl80211_data *drv,
			       enum nl80211_commands cmd, struct nlattr *status,
			       struct nlattr *addr, struct nlattr *req_ie,
			       struct nlattr *resp_ie,
			       struct nlattr *timed_out,
			       struct nlattr *timeout_reason,
			       struct nlattr *authorized,
			       struct nlattr *key_replay_ctr,
			       struct nlattr *ptk_kck,
			       struct nlattr *ptk_kek,
			       struct nlattr *subnet_status,
			       struct nlattr *fils_erp_next_seq_num,
			       struct nlattr *fils_pmk,
			       struct nlattr *fils_pmkid)
{
   
   
	union wpa_event_data event;
	const u8 *ssid = NULL;
	u16 status_code;
	int ssid_len;

    //wlan driver支持SME时的处理
	if (drv->capa.flags & WPA_DRIVER_FLAGS_SME) {
   
   
		/*
		 * Avoid reporting two association events that would confuse
		 * the core code.
		 */
		wpa_printf(MSG_DEBUG, "nl80211: Ignore connect event (cmd=%d) "
			   "when using userspace SME", cmd);
		return;
	}

	drv->connect_reassoc = 0;

	status_code = status ? nla_get_u16(status) : WLAN_STATUS_SUCCESS;

	if (cmd == NL80211_CMD_CONNECT) {
   
   
		wpa_printf(MSG_DEBUG,
			   "nl80211: Connect event (status=%u ignore_next_local_disconnect=%d)",
			   status_code, drv->ignore_next_local_disconnect);
	} else if (cmd == NL80211_CMD_ROAM) {
   
   
		wpa_printf(MSG_DEBUG, "nl80211: Roam event");
	}

	os_memset(&event, 0, sizeof(event));
	if (cmd == NL80211_CMD_CONNECT && status_code != WLAN_STATUS_SUCCESS) {
   
   
        //关联AP失败时的处理
		if (addr)
			event.assoc_reject.bssid = nla_data(addr);
		if (drv->ignore_next_local_disconnect) {
   
   
			drv->ignore_next_local_disconnect = 0;
			if (!event.assoc_reject.bssid ||
			    (os_memcmp(event.assoc_reject.bssid,
				       drv->auth_attempt_bssid,
				       ETH_ALEN) != 0)) {
   
   
				/*
				 * Ignore the event that came without a BSSID or
				 * for the old connection since this is likely
				 * not relevant to the new Connect command.
				 */
				wpa_printf(MSG_DEBUG,
					   "nl80211: Ignore connection failure event triggered during reassociation");
				return;
			}
		}
		if (resp_ie) {
   
   
			event.assoc_reject.resp_ies = nla_data(resp_ie);
			event.assoc_reject.resp_ies_len = nla_len(resp_ie);
		}
		event.assoc_reject.status_code = status_code;
		event.assoc_reject.timed_out = timed_out != NULL;
		if (timed_out && timeout_reason) {
   
   
			enum nl80211_timeout_reason reason;

			reason = nla_get_u32(timeout_reason);
			switch (reason) {
   
   
			case NL80211_TIMEOUT_SCAN:
				event.assoc_reject.timeout_reason = "scan";
				break;
			case NL80211_TIMEOUT_AUTH:
				event.assoc_reject.timeout_reason = "auth";
				break;
			case NL80211_TIMEOUT_ASSOC:
				event.assoc_reject.timeout_reason = "assoc";
				break;
			default:</