文章目录
- Action分析
- [Wi-Fi Direct分析](#Wi-Fi Direct分析)
- 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。
c
/* 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。
c
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
c
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
c
/**
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ID
const 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_INFO
const 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。
c
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_DISPLAY
struct 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 Direct
len = 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_DISPLAY
if (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。