本文為《深入理解Android Wi-Fi、NFC和GPS卷》讀書筆記，Android源碼為Android 5.1

根據(jù)7.3.2節(jié)中對 DISCOVER_PEERS 命令的代碼分析可知， P2pStateMachine將發(fā)送 P2P_FIND 120命令給WPAS觸發(fā)P2P Device Discovery流程。處理該命令的代碼如下：

android-5.1/external/wpa_supplicant_8/wpa_supplicant/ctrl_iface.c

char * wpa_supplicant_ctrl_iface_process(struct wpa_supplicant *wpa_s,char *buf, size_t *resp_len)
{char *reply;const int reply_size = 4096;int reply_len;if (os_strncmp(buf, WPA_CTRL_RSP, os_strlen(WPA_CTRL_RSP)) == 0 ||os_strncmp(buf, "SET_NETWORK ", 12) == 0) {if (wpa_debug_show_keys)wpa_dbg(wpa_s, MSG_DEBUG,"Control interface command '%s'", buf);elsewpa_dbg(wpa_s, MSG_DEBUG,"Control interface command '%s [REMOVED]'",os_strncmp(buf, WPA_CTRL_RSP,os_strlen(WPA_CTRL_RSP)) == 0 ?WPA_CTRL_RSP : "SET_NETWORK");} else if (os_strncmp(buf, "WPS_NFC_TAG_READ", 16) == 0 ||os_strncmp(buf, "NFC_REPORT_HANDOVER", 19) == 0) {wpa_hexdump_ascii_key(MSG_DEBUG, "RX ctrl_iface",(const u8 *) buf, os_strlen(buf));} else {int level = MSG_DEBUG;if (os_strcmp(buf, "PING") == 0)level = MSG_EXCESSIVE;wpa_dbg(wpa_s, level, "Control interface command '%s'", buf);}reply = os_malloc(reply_size);if (reply == NULL) {*resp_len = 1;return NULL;}os_memcpy(reply, "OK\n", 3);reply_len = 3;if (os_strcmp(buf, "PING") == 0) {os_memcpy(reply, "PONG\n", 5);reply_len = 5;} else if (os_strcmp(buf, "IFNAME") == 0) {reply_len = os_strlen(wpa_s->ifname);os_memcpy(reply, wpa_s->ifname, reply_len);} else if (os_strncmp(buf, "RELOG", 5) == 0) {if (wpa_debug_reopen_file() < 0)reply_len = -1;} else if (os_strncmp(buf, "NOTE ", 5) == 0) {wpa_printf(MSG_INFO, "NOTE: %s", buf + 5);} else if (os_strcmp(buf, "MIB") == 0) {reply_len = wpa_sm_get_mib(wpa_s->wpa, reply, reply_size);if (reply_len >= 0) {int res;res = eapol_sm_get_mib(wpa_s->eapol, reply + reply_len,reply_size - reply_len);if (res < 0)reply_len = -1;elsereply_len += res;}} else if (os_strncmp(buf, "STATUS", 6) == 0) {reply_len = wpa_supplicant_ctrl_iface_status(wpa_s, buf + 6, reply, reply_size);} else if (os_strcmp(buf, "PMKSA") == 0) {reply_len = wpa_sm_pmksa_cache_list(wpa_s->wpa, reply,reply_size);} else if (os_strcmp(buf, "PMKSA_FLUSH") == 0) {wpa_sm_pmksa_cache_flush(wpa_s->wpa, NULL);} else if (os_strncmp(buf, "SET ", 4) == 0) {if (wpa_supplicant_ctrl_iface_set(wpa_s, buf + 4))reply_len = -1;} else if (os_strncmp(buf, "GET ", 4) == 0) {reply_len = wpa_supplicant_ctrl_iface_get(wpa_s, buf + 4,reply, reply_size);} else if (os_strcmp(buf, "LOGON") == 0) {eapol_sm_notify_logoff(wpa_s->eapol, FALSE);} else if (os_strcmp(buf, "LOGOFF") == 0) {eapol_sm_notify_logoff(wpa_s->eapol, TRUE);} else if (os_strcmp(buf, "REASSOCIATE") == 0) {if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED)reply_len = -1;elsewpas_request_connection(wpa_s);} else if (os_strcmp(buf, "REATTACH") == 0) {if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED ||!wpa_s->current_ssid)reply_len = -1;else {wpa_s->reattach = 1;wpas_request_connection(wpa_s);}} else if (os_strcmp(buf, "RECONNECT") == 0) {if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED)reply_len = -1;else if (wpa_s->disconnected)wpas_request_connection(wpa_s);
#ifdef IEEE8021X_EAPOL} else if (os_strncmp(buf, "PREAUTH ", 8) == 0) {if (wpa_supplicant_ctrl_iface_preauth(wpa_s, buf + 8))reply_len = -1;
#endif /* IEEE8021X_EAPOL */
#ifdef CONFIG_PEERKEY} else if (os_strncmp(buf, "STKSTART ", 9) == 0) {if (wpa_supplicant_ctrl_iface_stkstart(wpa_s, buf + 9))reply_len = -1;
#endif /* CONFIG_PEERKEY */
#ifdef CONFIG_IEEE80211R} else if (os_strncmp(buf, "FT_DS ", 6) == 0) {if (wpa_supplicant_ctrl_iface_ft_ds(wpa_s, buf + 6))reply_len = -1;
#endif /* CONFIG_IEEE80211R */
#ifdef CONFIG_WPS} else if (os_strcmp(buf, "WPS_PBC") == 0) {int res = wpa_supplicant_ctrl_iface_wps_pbc(wpa_s, NULL);if (res == -2) {os_memcpy(reply, "FAIL-PBC-OVERLAP\n", 17);reply_len = 17;} else if (res)reply_len = -1;} else if (os_strncmp(buf, "WPS_PBC ", 8) == 0) {int res = wpa_supplicant_ctrl_iface_wps_pbc(wpa_s, buf + 8);if (res == -2) {os_memcpy(reply, "FAIL-PBC-OVERLAP\n", 17);reply_len = 17;} else if (res)reply_len = -1;} else if (os_strncmp(buf, "WPS_PIN ", 8) == 0) {reply_len = wpa_supplicant_ctrl_iface_wps_pin(wpa_s, buf + 8,reply,reply_size);} else if (os_strncmp(buf, "WPS_CHECK_PIN ", 14) == 0) {reply_len = wpa_supplicant_ctrl_iface_wps_check_pin(wpa_s, buf + 14, reply, reply_size);} else if (os_strcmp(buf, "WPS_CANCEL") == 0) {if (wpas_wps_cancel(wpa_s))reply_len = -1;
#ifdef CONFIG_WPS_NFC} else if (os_strcmp(buf, "WPS_NFC") == 0) {if (wpa_supplicant_ctrl_iface_wps_nfc(wpa_s, NULL))reply_len = -1;} else if (os_strncmp(buf, "WPS_NFC ", 8) == 0) {if (wpa_supplicant_ctrl_iface_wps_nfc(wpa_s, buf + 8))reply_len = -1;} else if (os_strncmp(buf, "WPS_NFC_CONFIG_TOKEN ", 21) == 0) {reply_len = wpa_supplicant_ctrl_iface_wps_nfc_config_token(wpa_s, buf + 21, reply, reply_size);} else if (os_strncmp(buf, "WPS_NFC_TOKEN ", 14) == 0) {reply_len = wpa_supplicant_ctrl_iface_wps_nfc_token(wpa_s, buf + 14, reply, reply_size);} else if (os_strncmp(buf, "WPS_NFC_TAG_READ ", 17) == 0) {if (wpa_supplicant_ctrl_iface_wps_nfc_tag_read(wpa_s,buf + 17))reply_len = -1;} else if (os_strncmp(buf, "NFC_GET_HANDOVER_REQ ", 21) == 0) {reply_len = wpas_ctrl_nfc_get_handover_req(wpa_s, buf + 21, reply, reply_size);} else if (os_strncmp(buf, "NFC_GET_HANDOVER_SEL ", 21) == 0) {reply_len = wpas_ctrl_nfc_get_handover_sel(wpa_s, buf + 21, reply, reply_size);} else if (os_strncmp(buf, "NFC_REPORT_HANDOVER ", 20) == 0) {if (wpas_ctrl_nfc_report_handover(wpa_s, buf + 20))reply_len = -1;
#endif /* CONFIG_WPS_NFC */} else if (os_strncmp(buf, "WPS_REG ", 8) == 0) {if (wpa_supplicant_ctrl_iface_wps_reg(wpa_s, buf + 8))reply_len = -1;
#ifdef CONFIG_AP} else if (os_strncmp(buf, "WPS_AP_PIN ", 11) == 0) {reply_len = wpa_supplicant_ctrl_iface_wps_ap_pin(wpa_s, buf + 11, reply, reply_size);
#endif /* CONFIG_AP */
#ifdef CONFIG_WPS_ER} else if (os_strcmp(buf, "WPS_ER_START") == 0) {if (wpas_wps_er_start(wpa_s, NULL))reply_len = -1;} else if (os_strncmp(buf, "WPS_ER_START ", 13) == 0) {if (wpas_wps_er_start(wpa_s, buf + 13))reply_len = -1;} else if (os_strcmp(buf, "WPS_ER_STOP") == 0) {if (wpas_wps_er_stop(wpa_s))reply_len = -1;} else if (os_strncmp(buf, "WPS_ER_PIN ", 11) == 0) {if (wpa_supplicant_ctrl_iface_wps_er_pin(wpa_s, buf + 11))reply_len = -1;} else if (os_strncmp(buf, "WPS_ER_PBC ", 11) == 0) {int ret = wpas_wps_er_pbc(wpa_s, buf + 11);if (ret == -2) {os_memcpy(reply, "FAIL-PBC-OVERLAP\n", 17);reply_len = 17;} else if (ret == -3) {os_memcpy(reply, "FAIL-UNKNOWN-UUID\n", 18);reply_len = 18;} else if (ret == -4) {os_memcpy(reply, "FAIL-NO-AP-SETTINGS\n", 20);reply_len = 20;} else if (ret)reply_len = -1;} else if (os_strncmp(buf, "WPS_ER_LEARN ", 13) == 0) {if (wpa_supplicant_ctrl_iface_wps_er_learn(wpa_s, buf + 13))reply_len = -1;} else if (os_strncmp(buf, "WPS_ER_SET_CONFIG ", 18) == 0) {if (wpa_supplicant_ctrl_iface_wps_er_set_config(wpa_s,buf + 18))reply_len = -1;} else if (os_strncmp(buf, "WPS_ER_CONFIG ", 14) == 0) {if (wpa_supplicant_ctrl_iface_wps_er_config(wpa_s, buf + 14))reply_len = -1;
#ifdef CONFIG_WPS_NFC} else if (os_strncmp(buf, "WPS_ER_NFC_CONFIG_TOKEN ", 24) == 0) {reply_len = wpa_supplicant_ctrl_iface_wps_er_nfc_config_token(wpa_s, buf + 24, reply, reply_size);
#endif /* CONFIG_WPS_NFC */
#endif /* CONFIG_WPS_ER */
#endif /* CONFIG_WPS */
#ifdef CONFIG_IBSS_RSN} else if (os_strncmp(buf, "IBSS_RSN ", 9) == 0) {if (wpa_supplicant_ctrl_iface_ibss_rsn(wpa_s, buf + 9))reply_len = -1;
#endif /* CONFIG_IBSS_RSN */
#ifdef CONFIG_P2P} else if (os_strncmp(buf, "P2P_FIND ", 9) == 0) {//注意 "P2P_FIND "多了一個空格if (p2p_ctrl_find(wpa_s, buf + 9))reply_len = -1;} else if (os_strcmp(buf, "P2P_FIND") == 0) {//處理不帶參數(shù)的P2P_FIND命令if (p2p_ctrl_find(wpa_s, ""))reply_len = -1;//其他P2P命令} else if (os_strcmp(buf, "P2P_STOP_FIND") == 0) {wpas_p2p_stop_find(wpa_s);} else if (os_strncmp(buf, "P2P_CONNECT ", 12) == 0) {reply_len = p2p_ctrl_connect(wpa_s, buf + 12, reply,reply_size);} else if (os_strncmp(buf, "P2P_LISTEN ", 11) == 0) {if (p2p_ctrl_listen(wpa_s, buf + 11))reply_len = -1;} else if (os_strcmp(buf, "P2P_LISTEN") == 0) {if (p2p_ctrl_listen(wpa_s, ""))reply_len = -1;} else if (os_strncmp(buf, "P2P_GROUP_REMOVE ", 17) == 0) {if (wpas_p2p_group_remove(wpa_s, buf + 17))reply_len = -1;} else if (os_strcmp(buf, "P2P_GROUP_ADD") == 0) {if (wpas_p2p_group_add(wpa_s, 0, 0, 0, 0))reply_len = -1;} else if (os_strncmp(buf, "P2P_GROUP_ADD ", 14) == 0) {if (p2p_ctrl_group_add(wpa_s, buf + 14))reply_len = -1;} else if (os_strncmp(buf, "P2P_PROV_DISC ", 14) == 0) {if (p2p_ctrl_prov_disc(wpa_s, buf + 14))reply_len = -1;} else if (os_strcmp(buf, "P2P_GET_PASSPHRASE") == 0) {reply_len = p2p_get_passphrase(wpa_s, reply, reply_size);} else if (os_strncmp(buf, "P2P_SERV_DISC_REQ ", 18) == 0) {reply_len = p2p_ctrl_serv_disc_req(wpa_s, buf + 18, reply,reply_size);} else if (os_strncmp(buf, "P2P_SERV_DISC_CANCEL_REQ ", 25) == 0) {if (p2p_ctrl_serv_disc_cancel_req(wpa_s, buf + 25) < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_SERV_DISC_RESP ", 19) == 0) {if (p2p_ctrl_serv_disc_resp(wpa_s, buf + 19) < 0)reply_len = -1;} else if (os_strcmp(buf, "P2P_SERVICE_UPDATE") == 0) {wpas_p2p_sd_service_update(wpa_s);} else if (os_strncmp(buf, "P2P_SERV_DISC_EXTERNAL ", 23) == 0) {if (p2p_ctrl_serv_disc_external(wpa_s, buf + 23) < 0)reply_len = -1;} else if (os_strcmp(buf, "P2P_SERVICE_FLUSH") == 0) {wpas_p2p_service_flush(wpa_s);} else if (os_strncmp(buf, "P2P_SERVICE_ADD ", 16) == 0) {if (p2p_ctrl_service_add(wpa_s, buf + 16) < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_SERVICE_DEL ", 16) == 0) {if (p2p_ctrl_service_del(wpa_s, buf + 16) < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_REJECT ", 11) == 0) {if (p2p_ctrl_reject(wpa_s, buf + 11) < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_INVITE ", 11) == 0) {if (p2p_ctrl_invite(wpa_s, buf + 11) < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_PEER ", 9) == 0) {reply_len = p2p_ctrl_peer(wpa_s, buf + 9, reply,reply_size);} else if (os_strncmp(buf, "P2P_SET ", 8) == 0) {if (p2p_ctrl_set(wpa_s, buf + 8) < 0)reply_len = -1;} else if (os_strcmp(buf, "P2P_FLUSH") == 0) {p2p_ctrl_flush(wpa_s);} else if (os_strncmp(buf, "P2P_UNAUTHORIZE ", 16) == 0) {if (wpas_p2p_unauthorize(wpa_s, buf + 16) < 0)reply_len = -1;} else if (os_strcmp(buf, "P2P_CANCEL") == 0) {if (wpas_p2p_cancel(wpa_s))reply_len = -1;} else if (os_strncmp(buf, "P2P_PRESENCE_REQ ", 17) == 0) {if (p2p_ctrl_presence_req(wpa_s, buf + 17) < 0)reply_len = -1;} else if (os_strcmp(buf, "P2P_PRESENCE_REQ") == 0) {if (p2p_ctrl_presence_req(wpa_s, "") < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_EXT_LISTEN ", 15) == 0) {if (p2p_ctrl_ext_listen(wpa_s, buf + 15) < 0)reply_len = -1;} else if (os_strcmp(buf, "P2P_EXT_LISTEN") == 0) {if (p2p_ctrl_ext_listen(wpa_s, "") < 0)reply_len = -1;} else if (os_strncmp(buf, "P2P_REMOVE_CLIENT ", 18) == 0) {if (p2p_ctrl_remove_client(wpa_s, buf + 18) < 0)reply_len = -1;
#endif /* CONFIG_P2P */
#ifdef CONFIG_WIFI_DISPLAY} else if (os_strncmp(buf, "WFD_SUBELEM_SET ", 16) == 0) {if (wifi_display_subelem_set(wpa_s->global, buf + 16) < 0)reply_len = -1;} else if (os_strncmp(buf, "WFD_SUBELEM_GET ", 16) == 0) {reply_len = wifi_display_subelem_get(wpa_s->global, buf + 16,reply, reply_size);
#endif /* CONFIG_WIFI_DISPLAY */
#ifdef CONFIG_INTERWORKING} else if (os_strcmp(buf, "FETCH_ANQP") == 0) {if (interworking_fetch_anqp(wpa_s) < 0)reply_len = -1;} else if (os_strcmp(buf, "STOP_FETCH_ANQP") == 0) {interworking_stop_fetch_anqp(wpa_s);} else if (os_strcmp(buf, "INTERWORKING_SELECT") == 0) {if (ctrl_interworking_select(wpa_s, NULL) < 0)reply_len = -1;} else if (os_strncmp(buf, "INTERWORKING_SELECT ", 20) == 0) {if (ctrl_interworking_select(wpa_s, buf + 20) < 0)reply_len = -1;} else if (os_strncmp(buf, "INTERWORKING_CONNECT ", 21) == 0) {if (ctrl_interworking_connect(wpa_s, buf + 21) < 0)reply_len = -1;} else if (os_strncmp(buf, "ANQP_GET ", 9) == 0) {if (get_anqp(wpa_s, buf + 9) < 0)reply_len = -1;} else if (os_strncmp(buf, "GAS_REQUEST ", 12) == 0) {if (gas_request(wpa_s, buf + 12) < 0)reply_len = -1;} else if (os_strncmp(buf, "GAS_RESPONSE_GET ", 17) == 0) {reply_len = gas_response_get(wpa_s, buf + 17, reply,reply_size);
#endif /* CONFIG_INTERWORKING */
#ifdef CONFIG_HS20} else if (os_strncmp(buf, "HS20_ANQP_GET ", 14) == 0) {if (get_hs20_anqp(wpa_s, buf + 14) < 0)reply_len = -1;} else if (os_strncmp(buf, "HS20_GET_NAI_HOME_REALM_LIST ", 29) == 0) {if (hs20_get_nai_home_realm_list(wpa_s, buf + 29) < 0)reply_len = -1;} else if (os_strncmp(buf, "HS20_ICON_REQUEST ", 18) == 0) {if (hs20_icon_request(wpa_s, buf + 18) < 0)reply_len = -1;} else if (os_strcmp(buf, "FETCH_OSU") == 0) {if (hs20_fetch_osu(wpa_s) < 0)reply_len = -1;} else if (os_strcmp(buf, "CANCEL_FETCH_OSU") == 0) {hs20_cancel_fetch_osu(wpa_s);
#endif /* CONFIG_HS20 */} else if (os_strncmp(buf, WPA_CTRL_RSP, os_strlen(WPA_CTRL_RSP)) == 0){if (wpa_supplicant_ctrl_iface_ctrl_rsp(wpa_s, buf + os_strlen(WPA_CTRL_RSP)))reply_len = -1;else {/** Notify response from timeout to allow the control* interface response to be sent first.*/eloop_register_timeout(0, 0, wpas_ctrl_eapol_response,wpa_s, NULL);}} else if (os_strcmp(buf, "RECONFIGURE") == 0) {if (wpa_supplicant_reload_configuration(wpa_s))reply_len = -1;} else if (os_strcmp(buf, "TERMINATE") == 0) {wpa_supplicant_terminate_proc(wpa_s->global);} else if (os_strncmp(buf, "BSSID ", 6) == 0) {if (wpa_supplicant_ctrl_iface_bssid(wpa_s, buf + 6))reply_len = -1;} else if (os_strncmp(buf, "BLACKLIST", 9) == 0) {reply_len = wpa_supplicant_ctrl_iface_blacklist(wpa_s, buf + 9, reply, reply_size);} else if (os_strncmp(buf, "LOG_LEVEL", 9) == 0) {reply_len = wpa_supplicant_ctrl_iface_log_level(wpa_s, buf + 9, reply, reply_size);} else if (os_strncmp(buf, "LIST_NETWORKS ", 14) == 0) {reply_len = wpa_supplicant_ctrl_iface_list_networks(wpa_s, buf + 14, reply, reply_size);} else if (os_strcmp(buf, "LIST_NETWORKS") == 0) {reply_len = wpa_supplicant_ctrl_iface_list_networks(wpa_s, NULL, reply, reply_size);} else if (os_strcmp(buf, "DISCONNECT") == 0) {
#ifdef CONFIG_SMEwpa_s->sme.prev_bssid_set = 0;
#endif /* CONFIG_SME */wpa_s->reassociate = 0;wpa_s->disconnected = 1;wpa_supplicant_cancel_sched_scan(wpa_s);wpa_supplicant_cancel_scan(wpa_s);wpa_supplicant_deauthenticate(wpa_s,WLAN_REASON_DEAUTH_LEAVING);} else if (os_strcmp(buf, "SCAN") == 0) {wpas_ctrl_scan(wpa_s, NULL, reply, reply_size, &reply_len);} else if (os_strncmp(buf, "SCAN ", 5) == 0) {wpas_ctrl_scan(wpa_s, buf + 5, reply, reply_size, &reply_len);} else if (os_strcmp(buf, "SCAN_RESULTS") == 0) {reply_len = wpa_supplicant_ctrl_iface_scan_results(wpa_s, reply, reply_size);} else if (os_strncmp(buf, "SELECT_NETWORK ", 15) == 0) {if (wpa_supplicant_ctrl_iface_select_network(wpa_s, buf + 15))reply_len = -1;} else if (os_strncmp(buf, "ENABLE_NETWORK ", 15) == 0) {if (wpa_supplicant_ctrl_iface_enable_network(wpa_s, buf + 15))reply_len = -1;} else if (os_strncmp(buf, "DISABLE_NETWORK ", 16) == 0) {if (wpa_supplicant_ctrl_iface_disable_network(wpa_s, buf + 16))reply_len = -1;} else if (os_strcmp(buf, "ADD_NETWORK") == 0) {reply_len = wpa_supplicant_ctrl_iface_add_network(wpa_s, reply, reply_size);} else if (os_strncmp(buf, "REMOVE_NETWORK ", 15) == 0) {if (wpa_supplicant_ctrl_iface_remove_network(wpa_s, buf + 15))reply_len = -1;} else if (os_strncmp(buf, "SET_NETWORK ", 12) == 0) {if (wpa_supplicant_ctrl_iface_set_network(wpa_s, buf + 12))reply_len = -1;} else if (os_strncmp(buf, "GET_NETWORK ", 12) == 0) {reply_len = wpa_supplicant_ctrl_iface_get_network(wpa_s, buf + 12, reply, reply_size);} else if (os_strncmp(buf, "DUP_NETWORK ", 12) == 0) {if (wpa_supplicant_ctrl_iface_dup_network(wpa_s, buf + 12))reply_len = -1;} else if (os_strcmp(buf, "LIST_CREDS") == 0) {reply_len = wpa_supplicant_ctrl_iface_list_creds(wpa_s, reply, reply_size);} else if (os_strcmp(buf, "ADD_CRED") == 0) {reply_len = wpa_supplicant_ctrl_iface_add_cred(wpa_s, reply, reply_size);} else if (os_strncmp(buf, "REMOVE_CRED ", 12) == 0) {if (wpa_supplicant_ctrl_iface_remove_cred(wpa_s, buf + 12))reply_len = -1;} else if (os_strncmp(buf, "SET_CRED ", 9) == 0) {if (wpa_supplicant_ctrl_iface_set_cred(wpa_s, buf + 9))reply_len = -1;} else if (os_strncmp(buf, "GET_CRED ", 9) == 0) {reply_len = wpa_supplicant_ctrl_iface_get_cred(wpa_s, buf + 9,reply,reply_size);
#ifndef CONFIG_NO_CONFIG_WRITE} else if (os_strcmp(buf, "SAVE_CONFIG") == 0) {if (wpa_supplicant_ctrl_iface_save_config(wpa_s))reply_len = -1;
#endif /* CONFIG_NO_CONFIG_WRITE */} else if (os_strncmp(buf, "GET_CAPABILITY ", 15) == 0) {reply_len = wpa_supplicant_ctrl_iface_get_capability(wpa_s, buf + 15, reply, reply_size);} else if (os_strncmp(buf, "AP_SCAN ", 8) == 0) {if (wpa_supplicant_ctrl_iface_ap_scan(wpa_s, buf + 8))reply_len = -1;} else if (os_strncmp(buf, "SCAN_INTERVAL ", 14) == 0) {if (wpa_supplicant_ctrl_iface_scan_interval(wpa_s, buf + 14))reply_len = -1;} else if (os_strcmp(buf, "INTERFACE_LIST") == 0) {reply_len = wpa_supplicant_global_iface_list(wpa_s->global, reply, reply_size);} else if (os_strcmp(buf, "INTERFACES") == 0) {reply_len = wpa_supplicant_global_iface_interfaces(wpa_s->global, reply, reply_size);} else if (os_strncmp(buf, "BSS ", 4) == 0) {reply_len = wpa_supplicant_ctrl_iface_bss(wpa_s, buf + 4, reply, reply_size);
#ifdef CONFIG_AP} else if (os_strcmp(buf, "STA-FIRST") == 0) {reply_len = ap_ctrl_iface_sta_first(wpa_s, reply, reply_size);} else if (os_strncmp(buf, "STA ", 4) == 0) {reply_len = ap_ctrl_iface_sta(wpa_s, buf + 4, reply,reply_size);} else if (os_strncmp(buf, "STA-NEXT ", 9) == 0) {reply_len = ap_ctrl_iface_sta_next(wpa_s, buf + 9, reply,reply_size);} else if (os_strncmp(buf, "DEAUTHENTICATE ", 15) == 0) {if (ap_ctrl_iface_sta_deauthenticate(wpa_s, buf + 15))reply_len = -1;} else if (os_strncmp(buf, "DISASSOCIATE ", 13) == 0) {if (ap_ctrl_iface_sta_disassociate(wpa_s, buf + 13))reply_len = -1;} else if (os_strncmp(buf, "CHAN_SWITCH ", 12) == 0) {if (ap_ctrl_iface_chanswitch(wpa_s, buf + 12))reply_len = -1;
#endif /* CONFIG_AP */} else if (os_strcmp(buf, "SUSPEND") == 0) {wpas_notify_suspend(wpa_s->global);} else if (os_strcmp(buf, "RESUME") == 0) {wpas_notify_resume(wpa_s->global);
#ifdef CONFIG_TESTING_OPTIONS} else if (os_strcmp(buf, "DROP_SA") == 0) {wpa_supplicant_ctrl_iface_drop_sa(wpa_s);
#endif /* CONFIG_TESTING_OPTIONS */} else if (os_strncmp(buf, "ROAM ", 5) == 0) {if (wpa_supplicant_ctrl_iface_roam(wpa_s, buf + 5))reply_len = -1;} else if (os_strncmp(buf, "STA_AUTOCONNECT ", 16) == 0) {if (wpa_supplicant_ctrl_iface_sta_autoconnect(wpa_s, buf + 16))reply_len = -1;} else if (os_strncmp(buf, "BSS_EXPIRE_AGE ", 15) == 0) {if (wpa_supplicant_ctrl_iface_bss_expire_age(wpa_s, buf + 15))reply_len = -1;} else if (os_strncmp(buf, "BSS_EXPIRE_COUNT ", 17) == 0) {if (wpa_supplicant_ctrl_iface_bss_expire_count(wpa_s,buf + 17))reply_len = -1;} else if (os_strncmp(buf, "BSS_FLUSH ", 10) == 0) {if (wpa_supplicant_ctrl_iface_bss_flush(wpa_s, buf + 10))reply_len = -1;
#ifdef CONFIG_TDLS} else if (os_strncmp(buf, "TDLS_DISCOVER ", 14) == 0) {if (wpa_supplicant_ctrl_iface_tdls_discover(wpa_s, buf + 14))reply_len = -1;} else if (os_strncmp(buf, "TDLS_SETUP ", 11) == 0) {if (wpa_supplicant_ctrl_iface_tdls_setup(wpa_s, buf + 11))reply_len = -1;} else if (os_strncmp(buf, "TDLS_TEARDOWN ", 14) == 0) {if (wpa_supplicant_ctrl_iface_tdls_teardown(wpa_s, buf + 14))reply_len = -1;
#endif /* CONFIG_TDLS */} else if (os_strncmp(buf, "SIGNAL_POLL", 11) == 0) {reply_len = wpa_supplicant_signal_poll(wpa_s, reply,reply_size);} else if (os_strncmp(buf, "PKTCNT_POLL", 11) == 0) {reply_len = wpa_supplicant_pktcnt_poll(wpa_s, reply,reply_size);
#ifdef CONFIG_AUTOSCAN} else if (os_strncmp(buf, "AUTOSCAN ", 9) == 0) {if (wpa_supplicant_ctrl_iface_autoscan(wpa_s, buf + 9))reply_len = -1;
#endif /* CONFIG_AUTOSCAN */
#ifdef ANDROID} else if (os_strncmp(buf, "DRIVER ", 7) == 0) {reply_len = wpa_supplicant_driver_cmd(wpa_s, buf + 7, reply,reply_size);
#endif /* ANDROID */} else if (os_strncmp(buf, "VENDOR ", 7) == 0) {reply_len = wpa_supplicant_vendor_cmd(wpa_s, buf + 7, reply,reply_size);} else if (os_strcmp(buf, "REAUTHENTICATE") == 0) {pmksa_cache_clear_current(wpa_s->wpa);eapol_sm_request_reauth(wpa_s->eapol);
#ifdef CONFIG_WNM} else if (os_strncmp(buf, "WNM_SLEEP ", 10) == 0) {if (wpas_ctrl_iface_wnm_sleep(wpa_s, buf + 10))reply_len = -1;} else if (os_strncmp(buf, "WNM_BSS_QUERY ", 10) == 0) {if (wpas_ctrl_iface_wnm_bss_query(wpa_s, buf + 10))reply_len = -1;
#endif /* CONFIG_WNM */} else if (os_strcmp(buf, "FLUSH") == 0) {wpa_supplicant_ctrl_iface_flush(wpa_s);} else if (os_strncmp(buf, "RADIO_WORK ", 11) == 0) {reply_len = wpas_ctrl_radio_work(wpa_s, buf + 11, reply,reply_size);
#ifdef CONFIG_TESTING_OPTIONS} else if (os_strncmp(buf, "MGMT_TX ", 8) == 0) {if (wpas_ctrl_iface_mgmt_tx(wpa_s, buf + 8) < 0)reply_len = -1;} else if (os_strcmp(buf, "MGMT_TX_DONE") == 0) {wpas_ctrl_iface_mgmt_tx_done(wpa_s);} else if (os_strncmp(buf, "DRIVER_EVENT ", 13) == 0) {if (wpas_ctrl_iface_driver_event(wpa_s, buf + 13) < 0)reply_len = -1;
#endif /* CONFIG_TESTING_OPTIONS */} else if (os_strncmp(buf, "VENDOR_ELEM_ADD ", 16) == 0) {if (wpas_ctrl_vendor_elem_add(wpa_s, buf + 16) < 0)reply_len = -1;} else if (os_strncmp(buf, "VENDOR_ELEM_GET ", 16) == 0) {reply_len = wpas_ctrl_vendor_elem_get(wpa_s, buf + 16, reply,reply_size);} else if (os_strncmp(buf, "VENDOR_ELEM_REMOVE ", 19) == 0) {if (wpas_ctrl_vendor_elem_remove(wpa_s, buf + 19) < 0)reply_len = -1;} else {os_memcpy(reply, "UNKNOWN COMMAND\n", 16);reply_len = 16;}if (reply_len < 0) {os_memcpy(reply, "FAIL\n", 5);reply_len = 5;}*resp_len = reply_len;return reply;
}

不論 P2P_FIND 命令是否攜帶參數(shù)，其最終的處理函數(shù)都將是p2p_ctrl_find：
android-5.1/external/wpa_supplicant_8/wpa_supplicant/ctrl_iface.c

static int p2p_ctrl_find(struct wpa_supplicant *wpa_s, char *cmd)
{unsigned int timeout = atoi(cmd);//搜索方式enum p2p_discovery_type type = P2P_FIND_START_WITH_FULL;u8 dev_id[ETH_ALEN], *_dev_id = NULL;u8 dev_type[WPS_DEV_TYPE_LEN], *_dev_type = NULL;char *pos;unsigned int search_delay;if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {wpa_dbg(wpa_s, MSG_INFO,"Reject P2P_FIND since interface is disabled");return -1;}//設置搜索方式if (os_strstr(cmd, "type=social"))type = P2P_FIND_ONLY_SOCIAL;else if (os_strstr(cmd, "type=progressive"))type = P2P_FIND_PROGRESSIVE;pos = os_strstr(cmd, "dev_id=");//dev_id代表peer端device的MAC地址if (pos) {pos += 7;if (hwaddr_aton(pos, dev_id))return -1;_dev_id = dev_id;}pos = os_strstr(cmd, "dev_type=");if (pos) {pos += 9;if (wps_dev_type_str2bin(pos, dev_type) < 0)return -1;_dev_type = dev_type;}pos = os_strstr(cmd, "delay=");if (pos) {pos += 6;search_delay = atoi(pos);} elsesearch_delay = wpas_p2p_search_delay(wpa_s);//wpas_p2p_find將調(diào)用p2p_findreturn wpas_p2p_find(wpa_s, timeout, type, _dev_type != NULL, _dev_type,_dev_id, search_delay);
}

P2P_FIND支持三種不同的Discovery Type，分別如下：
P2P_FIND_START_WITH_FULL：默認設置。表示先掃描所有頻段，然后再掃描social channels。
P2P_FIND_ONLY_SOCIAL：只掃描social channels。它將跳過掃描所有頻段這一過程。這種搜索方式能加快搜索的速度。
P2P_FIND_PROGRESSIVE:它和 P2P_FIND_START_WITH_FULL類似，只不過在Search State階段將逐個掃描所有頻段。
P2P設備掃描流程從 wpas_p2p_find 開始，其代碼如下所示：
android-5.1/external/wpa_supplicant_8/wpa_supplicant/p2p_supplicant.c

int wpas_p2p_find(struct wpa_supplicant *wpa_s, unsigned int timeout,enum p2p_discovery_type type,unsigned int num_req_dev_types, const u8 *req_dev_types,const u8 *dev_id, unsigned int search_delay)
{//取消還未發(fā)送的Action 幀數(shù)據(jù)。WPAS中，待發(fā)送的Action幀數(shù)據(jù)保存在wpa_supplicant對象的pending_action_tx變量中，它指向一塊數(shù)據(jù)緩沖區(qū)wpas_p2p_clear_pending_action_tx(wpa_s);wpa_s->p2p_long_listen = 0;if (wpa_s->global->p2p_disabled || wpa_s->global->p2p == NULL ||wpa_s->p2p_in_provisioning)return -1;//取消計劃掃描任務wpa_supplicant_cancel_sched_scan(wpa_s);//調(diào)用 p2p_find 函數(shù)return p2p_find(wpa_s->global->p2p, timeout, type,num_req_dev_types, req_dev_types, dev_id,search_delay);
}

android-5.1/external/wpa_supplicant_8/src/p2p/p2p.c

int p2p_find(struct p2p_data *p2p, unsigned int timeout,enum p2p_discovery_type type,unsigned int num_req_dev_types, const u8 *req_dev_types,const u8 *dev_id, unsigned int search_delay)
{int res;p2p_dbg(p2p, "Starting find (type=%d)", type);os_get_reltime(&p2p->find_start);if (p2p->p2p_scan_running) {p2p_dbg(p2p, "p2p_scan is already running");}p2p_free_req_dev_types(p2p);if (req_dev_types && num_req_dev_types) {p2p->req_dev_types = os_malloc(num_req_dev_types *WPS_DEV_TYPE_LEN);if (p2p->req_dev_types == NULL)return -1;os_memcpy(p2p->req_dev_types, req_dev_types,num_req_dev_types * WPS_DEV_TYPE_LEN);p2p->num_req_dev_types = num_req_dev_types;}if (dev_id) {os_memcpy(p2p->find_dev_id_buf, dev_id, ETH_ALEN);p2p->find_dev_id = p2p->find_dev_id_buf;} elsep2p->find_dev_id = NULL;//P2P_AFTER_SCAN_NOTHING表示P2P設備完成scan動作后，無需做其他動作p2p->start_after_scan = P2P_AFTER_SCAN_NOTHING;p2p_clear_timeout(p2p);p2p->cfg->stop_listen(p2p->cfg->cb_ctx);//停止監(jiān)聽p2p->find_type = type;p2p_device_clear_reported(p2p);p2p_set_state(p2p, P2P_SEARCH);//設置P2P模塊的狀態(tài)為 P2P_SEARCHp2p->search_delay = search_delay;p2p->in_search_delay = 0;eloop_cancel_timeout(p2p_find_timeout, p2p, NULL);p2p->last_p2p_find_timeout = timeout;if (timeout)//注冊一個掃描超時處理任務eloop_register_timeout(timeout, 0, p2p_find_timeout,p2p, NULL);switch (type) {case P2P_FIND_START_WITH_FULL:case P2P_FIND_PROGRESSIVE:	//p2p_scan指向函數(shù) wpas_p2p_scanres = p2p->cfg->p2p_scan(p2p->cfg->cb_ctx, P2P_SCAN_FULL, 0,p2p->num_req_dev_types,p2p->req_dev_types, dev_id,DEV_PW_DEFAULT);break;case P2P_FIND_ONLY_SOCIAL:res = p2p->cfg->p2p_scan(p2p->cfg->cb_ctx, P2P_SCAN_SOCIAL, 0,p2p->num_req_dev_types,p2p->req_dev_types, dev_id,DEV_PW_DEFAULT);break;default:return -1;}if (res == 0) {p2p_dbg(p2p, "Running p2p_scan");//p2p_scan_running設置為1，后面多處會用到p2p->p2p_scan_running = 1;eloop_cancel_timeout(p2p_scan_timeout, p2p, NULL);eloop_register_timeout(P2P_SCAN_TIMEOUT, 0, p2p_scan_timeout,p2p, NULL);} else if (p2p->p2p_scan_running) {p2p_dbg(p2p, "Failed to start p2p_scan - another p2p_scan was already running");/* wait for the previous p2p_scan to complete */res = 0; /* do not report failure */} else {p2p_dbg(p2p, "Failed to start p2p_scan");p2p_set_state(p2p, P2P_IDLE);eloop_cancel_timeout(p2p_find_timeout, p2p, NULL);}return res;
}

p2p_scan指向函數(shù) wpas_p2p_scan
android-5.1/external/wpa_supplicant_8/wpa_supplicant/p2p_supplicant.c

static int wpas_p2p_scan(void *ctx, enum p2p_scan_type type, int freq,unsigned int num_req_dev_types,const u8 *req_dev_types, const u8 *dev_id, u16 pw_id)
{struct wpa_supplicant *wpa_s = ctx;//掃描參數(shù)struct wpa_driver_scan_params *params = NULL;struct wpabuf *wps_ie, *ies;unsigned int num_channels = 0;int social_channels_freq[] = { 2412, 2437, 2462, 60480 };size_t ielen;u8 *n, i;if (wpa_s->global->p2p_disabled || wpa_s->global->p2p == NULL)return -1;if (wpa_s->p2p_scan_work) {wpa_dbg(wpa_s, MSG_INFO, "P2P: Reject scan trigger since one is already pending");return -1;}params = os_zalloc(sizeof(*params));if (params == NULL)return -1;/* P2P Wildcard SSID */params->num_ssids = 1;n = os_malloc(P2P_WILDCARD_SSID_LEN);if (n == NULL)goto fail;//P2P_WILDCARD_SSID值為"DIRECT-"os_memcpy(n, P2P_WILDCARD_SSID, P2P_WILDCARD_SSID_LEN);params->ssids[0].ssid = n;params->ssids[0].ssid_len = P2P_WILDCARD_SSID_LEN;wpa_s->wps->dev.p2p = 1;//構(gòu)造Probe Request幀中WSC IE信息wps_ie = wps_build_probe_req_ie(pw_id, &wpa_s->wps->dev,wpa_s->wps->uuid, WPS_REQ_ENROLLEE,num_req_dev_types, req_dev_types);if (wps_ie == NULL)goto fail;ielen = p2p_scan_ie_buf_len(wpa_s->global->p2p);ies = wpabuf_alloc(wpabuf_len(wps_ie) + ielen);if (ies == NULL) {wpabuf_free(wps_ie);goto fail;}wpabuf_put_buf(ies, wps_ie);wpabuf_free(wps_ie);//構(gòu)造P2P IE信息p2p_scan_ie(wpa_s->global->p2p, ies, dev_id);params->p2p_probe = 1;n = os_malloc(wpabuf_len(ies));if (n == NULL) {wpabuf_free(ies);goto fail;}os_memcpy(n, wpabuf_head(ies), wpabuf_len(ies));params->extra_ies = n;params->extra_ies_len = wpabuf_len(ies);wpabuf_free(ies);switch (type) {case P2P_SCAN_SOCIAL://只掃描social channels的話，將設置params->freqs變量params->freqs = os_calloc(ARRAY_SIZE(social_channels_freq) + 1,sizeof(int));if (params->freqs == NULL)goto fail;for (i = 0; i < ARRAY_SIZE(social_channels_freq); i++) {if (p2p_supported_freq(wpa_s->global->p2p,social_channels_freq[i]))params->freqs[num_channels++] =social_channels_freq[i];}params->freqs[num_channels++] = 0;break;case P2P_SCAN_FULL:break;case P2P_SCAN_SOCIAL_PLUS_ONE:params->freqs = os_calloc(ARRAY_SIZE(social_channels_freq) + 2,sizeof(int));if (params->freqs == NULL)goto fail;for (i = 0; i < ARRAY_SIZE(social_channels_freq); i++) {if (p2p_supported_freq(wpa_s->global->p2p,social_channels_freq[i]))params->freqs[num_channels++] =social_channels_freq[i];}if (p2p_supported_freq(wpa_s->global->p2p, freq))params->freqs[num_channels++] = freq;params->freqs[num_channels++] = 0;break;}radio_remove_works(wpa_s, "p2p-scan", 0);if (radio_add_work(wpa_s, 0, "p2p-scan", 0, wpas_p2p_trigger_scan_cb,params) < 0)goto fail;return 0;fail:wpa_scan_free_params(params);return -1;
}

android-5.1/external/wpa_supplicant_8/wpa_supplicant/p2p_supplicant.c

static void wpas_p2p_trigger_scan_cb(struct wpa_radio_work *work, int deinit)
{struct wpa_supplicant *wpa_s = work->wpa_s;struct wpa_driver_scan_params *params = work->ctx;int ret;if (deinit) {if (!work->started) {wpa_scan_free_params(params);return;}wpa_s->p2p_scan_work = NULL;return;}//發(fā)起P2P設備掃描，該函數(shù)內(nèi)部將調(diào)用driver_nl80211.c的wpa_driver_nl80211_scan函數(shù)ret = wpa_drv_scan(wpa_s, params);wpa_scan_free_params(params);work->ctx = NULL;if (ret) {radio_work_done(work);return;}os_get_reltime(&wpa_s->scan_trigger_time);//設置P2P掃描結(jié)果處理函數(shù)wpa_s->scan_res_handler = wpas_p2p_scan_res_handler;wpa_s->own_scan_requested = 1;wpa_s->p2p_scan_work = work;
}

android-5.1/external/wpa_supplicant_8/wpa_supplicant/p2p_supplicant.c

static void wpas_p2p_scan_res_handler(struct wpa_supplicant *wpa_s,struct wpa_scan_results *scan_res)
{size_t i;if (wpa_s->p2p_scan_work) {struct wpa_radio_work *work = wpa_s->p2p_scan_work;wpa_s->p2p_scan_work = NULL;radio_work_done(work);}if (wpa_s->global->p2p_disabled || wpa_s->global->p2p == NULL)return;wpa_printf(MSG_DEBUG, "P2P: Scan results received (%d BSS)",(int) scan_res->num);for (i = 0; i < scan_res->num; i++) {struct wpa_scan_res *bss = scan_res->res[i];struct os_reltime time_tmp_age, entry_ts;const u8 *ies;size_t ies_len;time_tmp_age.sec = bss->age / 1000;time_tmp_age.usec = (bss->age % 1000) * 1000;os_reltime_sub(&scan_res->fetch_time, &time_tmp_age, &entry_ts);ies = (const u8 *) (bss + 1);ies_len = bss->ie_len;if (bss->beacon_ie_len > 0 &&!wpa_scan_get_vendor_ie(bss, P2P_IE_VENDOR_TYPE) &&wpa_scan_get_vendor_ie_beacon(bss, P2P_IE_VENDOR_TYPE)) {wpa_printf(MSG_DEBUG, "P2P: Use P2P IE(s) from Beacon frame since no P2P IE(s) in Probe Response frames received for "MACSTR, MAC2STR(bss->bssid));ies = ies + ies_len;ies_len = bss->beacon_ie_len;}//對每一個掃描結(jié)果調(diào)用p2p_scan_res_handler函數(shù)處理掃描結(jié)果if (p2p_scan_res_handler(wpa_s->global->p2p, bss->bssid,bss->freq, &entry_ts, bss->level,ies, ies_len) > 0)break;}p2p_scan_res_handled(wpa_s->global->p2p);//最后調(diào)用p2p_scan_res_handled
}

android-5.1/external/wpa_supplicant_8/src/p2p/p2p.c

int p2p_scan_res_handler(struct p2p_data *p2p, const u8 *bssid, int freq,struct os_reltime *rx_time, int level, const u8 *ies,size_t ies_len)
{if (os_reltime_before(rx_time, &p2p->find_start)) {/** The driver may have cached (e.g., in cfg80211 BSS table) the* scan results for relatively long time. To avoid reporting* stale information, update P2P peers only based on results* that have based on frames received after the last p2p_find* operation was started.*/p2p_dbg(p2p, "Ignore old scan result for " MACSTR" (rx_time=%u.%06u)",MAC2STR(bssid), (unsigned int) rx_time->sec,(unsigned int) rx_time->usec);return 0;}//添加一個P2P Devicep2p_add_device(p2p, bssid, freq, rx_time, level, ies, ies_len, 1);return 0;
}

android-5.1/external/wpa_supplicant_8/src/p2p/p2p.c

int p2p_add_device(struct p2p_data *p2p, const u8 *addr, int freq,struct os_reltime *rx_time, int level, const u8 *ies,size_t ies_len, int scan_res)
{struct p2p_device *dev;struct p2p_message msg;const u8 *p2p_dev_addr;int i;struct os_reltime time_now;os_memset(&msg, 0, sizeof(msg));//解析掃描結(jié)果中的IE信息，解析完的結(jié)果保存在一個p2p_message對象msg中if (p2p_parse_ies(ies, ies_len, &msg)) {p2p_dbg(p2p, "Failed to parse P2P IE for a device entry");p2p_parse_free(&msg);return -1;}//p2p device info中的屬性if (msg.p2p_device_addr)p2p_dev_addr = msg.p2p_device_addr;else if (msg.device_id)p2p_dev_addr = msg.device_id;else {p2p_dbg(p2p, "Ignore scan data without P2P Device Info or P2P Device Id");p2p_parse_free(&msg);return -1;}//過濾那些被阻止的P2P Deviceif (!is_zero_ether_addr(p2p->peer_filter) &&os_memcmp(p2p_dev_addr, p2p->peer_filter, ETH_ALEN) != 0) {p2p_dbg(p2p, "Do not add peer filter for " MACSTR" due to peer filter", MAC2STR(p2p_dev_addr));p2p_parse_free(&msg);return 0;}//構(gòu)造一個p2p_device對象，并將其加入p2p_data結(jié)構(gòu)體的 devices 鏈表中dev = p2p_create_device(p2p, p2p_dev_addr);if (dev == NULL) {p2p_parse_free(&msg);return -1;}if (rx_time == NULL) {os_get_reltime(&time_now);rx_time = &time_now;}/** Update the device entry only if the new peer* entry is newer than the one previously stored.*/if (dev->last_seen.sec > 0 &&os_reltime_before(rx_time, &dev->last_seen)) {p2p_dbg(p2p, "Do not update peer entry based on old frame (rx_time=%u.%06u last_seen=%u.%06u)",(unsigned int) rx_time->sec,(unsigned int) rx_time->usec,(unsigned int) dev->last_seen.sec,(unsigned int) dev->last_seen.usec);p2p_parse_free(&msg);return -1;}os_memcpy(&dev->last_seen, rx_time, sizeof(struct os_reltime));//p2p_device的flags變量代表該 p2p_device 的一些信息dev->flags &= ~(P2P_DEV_PROBE_REQ_ONLY | P2P_DEV_GROUP_CLIENT_ONLY);if (os_memcmp(addr, p2p_dev_addr, ETH_ALEN) != 0)os_memcpy(dev->interface_addr, addr, ETH_ALEN);if (msg.ssid &&(msg.ssid[1] != P2P_WILDCARD_SSID_LEN ||os_memcmp(msg.ssid + 2, P2P_WILDCARD_SSID, P2P_WILDCARD_SSID_LEN)!= 0)) {os_memcpy(dev->oper_ssid, msg.ssid + 2, msg.ssid[1]);dev->oper_ssid_len = msg.ssid[1];}if (freq >= 2412 && freq <= 2484 && msg.ds_params &&*msg.ds_params >= 1 && *msg.ds_params <= 14) {int ds_freq;if (*msg.ds_params == 14)ds_freq = 2484;elseds_freq = 2407 + *msg.ds_params * 5;if (freq != ds_freq) {p2p_dbg(p2p, "Update Listen frequency based on DS Parameter Set IE: %d -> %d MHz",freq, ds_freq);freq = ds_freq;}}if (dev->listen_freq && dev->listen_freq != freq && scan_res) {p2p_dbg(p2p, "Update Listen frequency based on scan results ("MACSTR " %d -> %d MHz (DS param %d)",MAC2STR(dev->info.p2p_device_addr), dev->listen_freq,freq, msg.ds_params ? *msg.ds_params : -1);}if (scan_res) {dev->listen_freq = freq;//如果對端P2P Device是GO，它回復的Probe Response幀P2P IE信息中將包含Group Info屬性if (msg.group_info)dev->oper_freq = freq;}dev->info.level = level;p2p_copy_wps_info(p2p, dev, 0, &msg);//復制WSC IEfor (i = 0; i < P2P_MAX_WPS_VENDOR_EXT; i++) {wpabuf_free(dev->info.wps_vendor_ext[i]);dev->info.wps_vendor_ext[i] = NULL;}for (i = 0; i < P2P_MAX_WPS_VENDOR_EXT; i++) {if (msg.wps_vendor_ext[i] == NULL)break;dev->info.wps_vendor_ext[i] = wpabuf_alloc_copy(msg.wps_vendor_ext[i], msg.wps_vendor_ext_len[i]);if (dev->info.wps_vendor_ext[i] == NULL)break;}if (msg.wfd_subelems) {wpabuf_free(dev->info.wfd_subelems);dev->info.wfd_subelems = wpabuf_dup(msg.wfd_subelems);}if (scan_res) {//根據(jù)Group Info信息添加Client。p2p_add_group_clients(p2p, p2p_dev_addr, addr, freq,msg.group_info, msg.group_info_len);}p2p_parse_free(&msg);p2p_update_peer_vendor_elems(dev, ies, ies_len);//P2P_DEV_REPORTED表示W(wǎng)PAS已向客戶端匯報過該P2P Device信息了if (dev->flags & P2P_DEV_REPORTED)return 0;p2p_dbg(p2p, "Peer found with Listen frequency %d MHz (rx_time=%u.%06u)",freq, (unsigned int) rx_time->sec,(unsigned int) rx_time->usec);//P2P_DEV_USER_REJECTED表示用戶拒絕P2P Device信息if (dev->flags & P2P_DEV_USER_REJECTED) {p2p_dbg(p2p, "Do not report rejected device");return 0;}if (dev->info.config_methods == 0 &&(freq == 2412 || freq == 2437 || freq == 2462)) {/** If we have only seen a Beacon frame from a GO, we do not yet* know what WPS config methods it supports. Since some* applications use config_methods value from P2P-DEVICE-FOUND* events, postpone reporting this peer until we've fully* discovered its capabilities.** At least for now, do this only if the peer was detected on* one of the social channels since that peer can be easily be* found again and there are no limitations of having to use* passive scan on this channels, so this can be done through* Probe Response frame that includes the config_methods* information.*/p2p_dbg(p2p, "Do not report peer " MACSTR" with unknown config methods", MAC2STR(addr));return 0;}//dev_found函數(shù)指針指向wpas_dev_found,該函數(shù)將向WiFiMonitor發(fā)送消息以告知我們找到了一個P2P Device，該消息也稱為P2P Device Found消息p2p->cfg->dev_found(p2p->cfg->cb_ctx, addr, &dev->info,!(dev->flags & P2P_DEV_REPORTED_ONCE));//下面這兩個標志表示該P2P Device已經(jīng)向客戶端匯報過并且匯報過一次了dev->flags |= P2P_DEV_REPORTED | P2P_DEV_REPORTED_ONCE;return 0;
}

android-5.1/external/wpa_supplicant_8/src/p2p/p2p.c

void p2p_scan_res_handled(struct p2p_data *p2p)
{if (!p2p->p2p_scan_running) {p2p_dbg(p2p, "p2p_scan was not running, but scan results received");}p2p->p2p_scan_running = 0; //設置p2p_scan_running值為0eloop_cancel_timeout(p2p_scan_timeout, p2p, NULL); //取消掃描超時處理任務//由于在p2p_scan函數(shù)中指定了 P2P_AFTER_SCAN_NOTHING標志，所以下面這個函數(shù)返回0if (p2p_run_after_scan(p2p))return;if (p2p->state == P2P_SEARCH)p2p_continue_find(p2p);
}

android-5.1/external/wpa_supplicant_8/src/p2p/p2p.c

void p2p_continue_find(struct p2p_data *p2p)
{struct p2p_device *dev;p2p_set_state(p2p, P2P_SEARCH);dl_list_for_each(dev, &p2p->devices, struct p2p_device, list) {if (dev->sd_pending_bcast_queries == 0) {/* Initialize with total number of registered broadcast* SD queries. */dev->sd_pending_bcast_queries = p2p->num_p2p_sd_queries;}if (p2p_start_sd(p2p, dev) == 0)return;if (dev->req_config_methods &&!(dev->flags & P2P_DEV_PD_FOR_JOIN)) {p2p_dbg(p2p, "Send pending Provision Discovery Request to "MACSTR " (config methods 0x%x)",MAC2STR(dev->info.p2p_device_addr),dev->req_config_methods);if (p2p_send_prov_disc_req(p2p, dev, 0, 0) == 0)return;}}p2p_listen_in_find(p2p, 1);
}

android-5.1/external/wpa_supplicant_8/src/p2p/p2p.c

static void p2p_listen_in_find(struct p2p_data *p2p, int dev_disc)
{unsigned int r, tu;int freq;struct wpabuf *ies;p2p_dbg(p2p, "Starting short listen state (state=%s)",p2p_state_txt(p2p->state));if (p2p->pending_listen_freq) {/* We have a pending p2p_listen request */p2p_dbg(p2p, "p2p_listen command pending already");return;}//根據(jù) p2p_supplicant.conf中l(wèi)isten_channel等配置參數(shù)獲取對應的頻段freq = p2p_channel_to_freq(p2p->cfg->reg_class, p2p->cfg->channel);if (freq < 0) {p2p_dbg(p2p, "Unknown regulatory class/channel");return;}//計算需要在listen state 等待的時間if (os_get_random((u8 *) &r, sizeof(r)) < 0)r = 0;tu = (r % ((p2p->max_disc_int - p2p->min_disc_int) + 1) +p2p->min_disc_int) * 100;if (p2p->max_disc_tu >= 0 && tu > (unsigned int) p2p->max_disc_tu)tu = p2p->max_disc_tu;if (!dev_disc && tu < 100)tu = 100; /* Need to wait in non-device discovery use cases */if (p2p->cfg->max_listen && 1024 * tu / 1000 > p2p->cfg->max_listen)tu = p2p->cfg->max_listen * 1000 / 1024;if (tu == 0) {p2p_dbg(p2p, "Skip listen state since duration was 0 TU");p2p_set_timeout(p2p, 0, 0);return;}//構(gòu)造P2P Probe Response幀，當我們在Listen state收到其他設備發(fā)來的Probe Request幀后，wifi驅(qū)動將直接回復此處設置的 P2P Probe Response幀。ies = p2p_build_probe_resp_ies(p2p);if (ies == NULL)return;p2p->pending_listen_freq = freq;p2p->pending_listen_sec = 0;p2p->pending_listen_usec = 1024 * tu;//start_listen指向 wpas_start_listen 函數(shù)if (p2p->cfg->start_listen(p2p->cfg->cb_ctx, freq, 1024 * tu / 1000,ies) < 0) {p2p_dbg(p2p, "Failed to start listen mode");p2p->pending_listen_freq = 0;}wpabuf_free(ies);
}

android-5.1/external/wpa_supplicant_8/wpa_supplicant/p2p_supplicant.c

static int wpas_start_listen(void *ctx, unsigned int freq,unsigned int duration,const struct wpabuf *probe_resp_ie)
{struct wpa_supplicant *wpa_s = ctx;struct wpas_p2p_listen_work *lwork;if (wpa_s->p2p_listen_work) {wpa_printf(MSG_DEBUG, "P2P: Reject start_listen since p2p_listen_work already exists");return -1;}lwork = os_zalloc(sizeof(*lwork));if (lwork == NULL)return -1;lwork->freq = freq;lwork->duration = duration;if (probe_resp_ie) {lwork->probe_resp_ie = wpabuf_dup(probe_resp_ie);if (lwork->probe_resp_ie == NULL) {wpas_p2p_listen_work_free(lwork);return -1;}}if (radio_add_work(wpa_s, freq, "p2p-listen", 0, wpas_start_listen_cb,lwork) < 0) {wpas_p2p_listen_work_free(lwork);return -1;}return 0;
}

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