P2P Device Discovery流程分析
杭英杰
本文为《深入理解Android Wi-Fi、NFC和GPS卷》读书笔记，Android源码为Android 5.1
根据7.3.2节中对 DISCOVER_PEERS 命令的代码分析可知， P2pStateMachine将发送 P2P_FIND 120命令给WPAS触发P2P Device Discovery流程。处理该命令的代码如下：
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);
else
wpa_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;
else
reply_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;
else
wpas_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 "多了一个空格
if (p2p_ctrl_find(wpa_s, buf + 9))
reply_len = -1;
} else if (os_strcmp(buf, "P2P_FIND") == 0) {
//处理不带参数的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_SME
wpa_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;
}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;
}
//设置搜索方式
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);
} else
search_delay = wpas_p2p_search_delay(wpa_s);
//wpas_p2p_find将调用p2p_find
return wpas_p2p_find(wpa_s, timeout, type, _dev_type != NULL, _dev_type,
_dev_id, search_delay);
}P2P_FIND_START_WITH_FULL：默认设置。表示先扫描所有频段，然后再扫描social channels。
P2P_FIND_ONLY_SOCIAL：只扫描social channels。它将跳过扫描所有频段这一过程。这种搜索方式能加快搜索的速度。
P2P_FIND_PROGRESSIVE:它和 P2P_FIND_START_WITH_FULL类似，只不过在Search State阶段将逐个扫描所有频段。
P2P设备扫描流程从 wpas_p2p_find 开始，其代码如下所示：
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)
{
//取消还未发送的Action 帧数据。WPAS中，待发送的Action帧数据保存在wpa_supplicant对象的pending_action_tx变量中，它指向一块数据缓冲区
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;
//取消计划扫描任务
wpa_supplicant_cancel_sched_scan(wpa_s);
//调用 p2p_find 函数
return p2p_find(wpa_s->global->p2p, timeout, type,
num_req_dev_types, req_dev_types, dev_id,
search_delay);
}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;
} else
p2p->find_dev_id = NULL;
//P2P_AFTER_SCAN_NOTHING表示P2P设备完成scan动作后，无需做其他动作
p2p->start_after_scan = P2P_AFTER_SCAN_NOTHING;
p2p_clear_timeout(p2p);
p2p->cfg->stop_listen(p2p->cfg->cb_ctx);//停止监听
p2p->find_type = type;
p2p_device_clear_reported(p2p);
p2p_set_state(p2p, P2P_SEARCH);//设置P2P模块的状态为 P2P_SEARCH
p2p->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)
//注册一个扫描超时处理任务
eloop_register_timeout(timeout, 0, p2p_find_timeout,
p2p, NULL);
switch (type) {
case P2P_FIND_START_WITH_FULL:
case P2P_FIND_PROGRESSIVE: //p2p_scan指向函数 wpas_p2p_scan
res = 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设置为1，后面多处会用到
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;
}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;
//扫描参数
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值为"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;
//构造Probe Request帧中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);
//构造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://只扫描social channels的话，将设置params->freqs变量
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;
}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;
}
//发起P2P设备扫描，该函数内部将调用driver_nl80211.c的wpa_driver_nl80211_scan函数
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);
//设置P2P扫描结果处理函数
wpa_s->scan_res_handler = wpas_p2p_scan_res_handler;
wpa_s->own_scan_requested = 1;
wpa_s->p2p_scan_work = work;
}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;
}
//对每一个扫描结果调用p2p_scan_res_handler函数处理扫描结果
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);//最后调用p2p_scan_res_handled
}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;
}
//添加一个P2P Device
p2p_add_device(p2p, bssid, freq, rx_time, level, ies, ies_len, 1);
return 0;
}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));
//解析扫描结果中的IE信息，解析完的结果保存在一个p2p_message对象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中的属性
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;
}
//过滤那些被阻止的P2P Device
if (!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;
}
//构造一个p2p_device对象，并将其加入p2p_data结构体的 devices 链表中
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变量代表该 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;
else
ds_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;
//如果对端P2P Device是GO，它回复的Probe Response帧P2P IE信息中将包含Group Info属性
if (msg.group_info)
dev->oper_freq = freq;
}
dev->info.level = level;
p2p_copy_wps_info(p2p, dev, 0, &msg);//复制WSC IE
for (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) {
//根据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WPAS已向客户端汇报过该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表示用户拒绝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函数指针指向wpas_dev_found,该函数将向WiFiMonitor发送消息以告知我们找到了一个P2P Device，该消息也称为P2P Device Found消息
p2p->cfg->dev_found(p2p->cfg->cb_ctx, addr, &dev->info,
!(dev->flags & P2P_DEV_REPORTED_ONCE));
//下面这两个标志表示该P2P Device已经向客户端汇报过并且汇报过一次了
dev->flags |= P2P_DEV_REPORTED | P2P_DEV_REPORTED_ONCE;
return 0;
}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; //设置p2p_scan_running值为0
eloop_cancel_timeout(p2p_scan_timeout, p2p, NULL); //取消扫描超时处理任务
//由于在p2p_scan函数中指定了 P2P_AFTER_SCAN_NOTHING标志，所以下面这个函数返回0
if (p2p_run_after_scan(p2p))
return;
if (p2p->state == P2P_SEARCH)
p2p_continue_find(p2p);
}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);
}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;
}
//根据 p2p_supplicant.conf中listen_channel等配置参数获取对应的频段
freq = p2p_channel_to_freq(p2p->cfg->reg_class, p2p->cfg->channel);
if (freq < 0) {
p2p_dbg(p2p, "Unknown regulatory class/channel");
return;
}
//计算需要在listen state 等待的时间
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;
}
//构造P2P Probe Response帧，当我们在Listen state收到其他设备发来的Probe Request帧后，wifi驱动将直接回复此处设置的 P2P Probe Response帧。
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 函数
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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