【Action帧简要分析】
文章目录
- Action分析
- Wi-Fi Direct分析
- p2p_attributes字段解析
- wfd_subelems字段解析
- wps字段解析
- p2p_message分析
- 邀请应答包构造
- 发送Action帧
Action分析
p2p_rx_action为P2P接收action帧入口函数。
- 判断category_code为WLAN_ACTION_PUBLIC(4)则调用p2p_rx_action_public函数。
- 判断action_code为WLAN_PA_VENDOR_SPECIFIC(9)且OUI和Subtype为P2P_IE_VENDOR_TYPE(0x506f9a09),则调用p2p_rx_p2p_action。
- 根据不同的OUI Subtype选择不同的处理流程。
/* P2P public action frames */
enum p2p_action_frame_type {P2P_GO_NEG_REQ = 0,P2P_GO_NEG_RESP = 1,P2P_GO_NEG_CONF = 2,P2P_INVITATION_REQ = 3,P2P_INVITATION_RESP = 4,P2P_DEV_DISC_REQ = 5,P2P_DEV_DISC_RESP = 6,P2P_PROV_DISC_REQ = 7,P2P_PROV_DISC_RESP = 8
};
Wi-Fi Direct分析
调用p2p_parse函数,先获取dialog_token,然后调用p2p_parse_ies进行解析。
ieee802_11_parse_elems解析elems字段。
- 判断element_id为WLAN_EID_VENDOR_SPECIFIC(221),调用ieee802_11_parse_vendor_specific。
- 判断OUI为OUI_WFA(0x506f9a)且OUI_type为P2P_OUI_TYPE。
p2p_attributes字段解析
调用p2p_parse_p2p_ie中p2p_parse_attribute解析P2P Attribute。
根据不同的ID走不同的流程,把解析出来的数据存入p2p_message。
enum p2p_attr_id {P2P_ATTR_STATUS = 0,P2P_ATTR_MINOR_REASON_CODE = 1,P2P_ATTR_CAPABILITY = 2,P2P_ATTR_DEVICE_ID = 3,P2P_ATTR_GROUP_OWNER_INTENT = 4,P2P_ATTR_CONFIGURATION_TIMEOUT = 5,P2P_ATTR_LISTEN_CHANNEL = 6,P2P_ATTR_GROUP_BSSID = 7,P2P_ATTR_EXT_LISTEN_TIMING = 8,P2P_ATTR_INTENDED_INTERFACE_ADDR = 9,P2P_ATTR_MANAGEABILITY = 10,P2P_ATTR_CHANNEL_LIST = 11,P2P_ATTR_NOTICE_OF_ABSENCE = 12,P2P_ATTR_DEVICE_INFO = 13,P2P_ATTR_GROUP_INFO = 14,P2P_ATTR_GROUP_ID = 15,P2P_ATTR_INTERFACE = 16,P2P_ATTR_OPERATING_CHANNEL = 17,P2P_ATTR_INVITATION_FLAGS = 18,P2P_ATTR_OOB_GO_NEG_CHANNEL = 19,P2P_ATTR_SERVICE_HASH = 21,P2P_ATTR_SESSION_INFORMATION_DATA = 22,P2P_ATTR_CONNECTION_CAPABILITY = 23,P2P_ATTR_ADVERTISEMENT_ID = 24,P2P_ATTR_ADVERTISED_SERVICE = 25,P2P_ATTR_SESSION_ID = 26,P2P_ATTR_FEATURE_CAPABILITY = 27,P2P_ATTR_PERSISTENT_GROUP = 28,P2P_ATTR_VENDOR_SPECIFIC = 221
};
wfd_subelems字段解析
enum wifi_display_subelem {WFD_SUBELEM_DEVICE_INFO = 0,WFD_SUBELEM_ASSOCIATED_BSSID = 1,WFD_SUBELEM_AUDIO_FORMATS = 2,WFD_SUBELEM_VIDEO_FORMATS = 3,WFD_SUBELEM_3D_VIDEO_FORMATS = 4,WFD_SUBELEM_CONTENT_PROTECTION = 5,WFD_SUBELEM_COUPLED_SINK = 6,WFD_SUBELEM_EXT_CAPAB = 7,WFD_SUBELEM_LOCAL_IP_ADDRESS = 8,WFD_SUBELEM_SESSION_INFO = 9
};
wps字段解析
根据OUI_MICROSOFT进行解析。
p2p_message分析
/**1. struct p2p_message - Parsed P2P message (or P2P IE)*/
struct p2p_message {struct wpabuf *p2p_attributes;//p2p属性struct wpabuf *wps_attributes;struct wpabuf *wfd_subelems;//wfd子属性u8 dialog_token;const u8 *capability;const u8 *go_intent;const u8 *status;//状态const u8 *listen_channel;//监听信道const u8 *operating_channel;//协商信道const u8 *channel_list;//信道列表u8 channel_list_len;const u8 *config_timeout;const u8 *intended_addr;const u8 *group_bssid;//对端MAC地址const u8 *invitation_flags;const u8 *group_info;size_t group_info_len;const u8 *group_id;size_t group_id_len;const u8 *device_id;//设备IDconst u8 *manageability;const u8 *noa;size_t noa_len;const u8 *ext_listen_timing;const u8 *minor_reason_code;const u8 *oob_go_neg_channel;/* P2P Device Info *///P2P_ATTR_DEVICE_INFOconst u8 *p2p_device_info;size_t p2p_device_info_len;const u8 *p2p_device_addr;const u8 *pri_dev_type;u8 num_sec_dev_types;char device_name[WPS_DEV_NAME_MAX_LEN + 1];u16 config_methods;/* WPS IE */u16 dev_password_id;int dev_password_id_present;u16 wps_config_methods;const u8 *wps_pri_dev_type;const u8 *wps_sec_dev_type_list;size_t wps_sec_dev_type_list_len;const u8 *wps_vendor_ext[P2P_MAX_WPS_VENDOR_EXT];size_t wps_vendor_ext_len[P2P_MAX_WPS_VENDOR_EXT];const u8 *manufacturer;size_t manufacturer_len;const u8 *model_name;size_t model_name_len;const u8 *model_number;size_t model_number_len;const u8 *serial_number;size_t serial_number_len;const u8 *oob_dev_password;size_t oob_dev_password_len;/* DS Parameter Set IE */const u8 *ds_params;/* SSID IE */const u8 *ssid;/* P2PS */u8 service_hash_count;const u8 *service_hash;const u8 *session_info;size_t session_info_len;const u8 *conn_cap;const u8 *adv_id;const u8 *adv_mac;const u8 *adv_service_instance;size_t adv_service_instance_len;const u8 *session_id;const u8 *session_mac;const u8 *feature_cap;size_t feature_cap_len;const u8 *persistent_dev;const u8 *persistent_ssid;size_t persistent_ssid_len;const u8 *pref_freq_list;size_t pref_freq_list_len;
};
邀请应答包构造
p2p_build_invitation_resp进行邀请应答包构造。
static struct wpabuf * p2p_build_invitation_resp(struct p2p_data *p2p,struct p2p_device *peer,u8 dialog_token, u8 status,const u8 *group_bssid,u8 reg_class, u8 channel,struct p2p_channels *channels)
{struct wpabuf *buf;u8 *len;size_t extra = 0;#ifdef CONFIG_WIFI_DISPLAYstruct wpabuf *wfd_ie = p2p->wfd_ie_invitation;if (wfd_ie && group_bssid) {size_t i;for (i = 0; i < p2p->num_groups; i++) {struct p2p_group *g = p2p->groups[i];struct wpabuf *ie;if (os_memcmp(p2p_group_get_interface_addr(g),group_bssid, ETH_ALEN) != 0)continue;ie = p2p_group_get_wfd_ie(g);if (ie) {wfd_ie = ie;break;}}}if (wfd_ie)extra = wpabuf_len(wfd_ie);
#endif /* CONFIG_WIFI_DISPLAY */if (p2p->vendor_elem && p2p->vendor_elem[VENDOR_ELEM_P2P_INV_RESP])extra += wpabuf_len(p2p->vendor_elem[VENDOR_ELEM_P2P_INV_RESP]);buf = wpabuf_alloc(1000 + extra);if (buf == NULL)return NULL;//构造头部p2p_buf_add_public_action_hdr(buf, P2P_INVITATION_RESP,dialog_token);//构造Wi-Fi Directlen = p2p_buf_add_ie_hdr(buf);//构造状态p2p_buf_add_status(buf, status);//构造超时p2p_buf_add_config_timeout(buf, 0, 0); /* FIX *///构造协商信道if (reg_class && channel)p2p_buf_add_operating_channel(buf, p2p->cfg->country,reg_class, channel);//构造MAC地址if (group_bssid)p2p_buf_add_group_bssid(buf, group_bssid);//构造信道列表if (channels)p2p_buf_add_channel_list(buf, p2p->cfg->country, channels);p2p_buf_update_ie_hdr(buf, len);#ifdef CONFIG_WIFI_DISPLAYif (wfd_ie)wpabuf_put_buf(buf, wfd_ie);
#endif /* CONFIG_WIFI_DISPLAY */if (p2p->vendor_elem && p2p->vendor_elem[VENDOR_ELEM_P2P_INV_RESP])wpabuf_put_buf(buf, p2p->vendor_elem[VENDOR_ELEM_P2P_INV_RESP]);return buf;
}
发送Action帧
调用p2p_send_action发送。