Android Wi-Fi源码分析之wpa_supplicant初始化(三):wpa_supplicant_add_iface函数分析
路径为:external\wpa_supplicant_8\wpa_supplicant\wpa_supplicant.c
/**
* wpa_supplicant_add_iface - Add a new network interface
* @global: Pointer to global data from wpa_supplicant_init()
* @iface: Interface configuration options
* Returns: Pointer to the created interface or %NULL on failure
*
* This function is used to add new network interfaces for %wpa_supplicant.
* This can be called before wpa_supplicant_run() to add interfaces before the
* main event loop has been started. In addition, new interfaces can be added
* dynamically while %wpa_supplicant is already running. This could happen,
* e.g., when a hotplug network adapter is inserted.
*/
struct wpa_supplicant * wpa_supplicant_add_iface(struct wpa_global *global,
struct wpa_interface *iface)
{
struct wpa_supplicant *wpa_s;
struct wpa_interface t_iface;
struct wpa_ssid *ssid;
if (global == NULL || iface == NULL)
return NULL;
wpa_s = wpa_supplicant_alloc();
if (wpa_s == NULL)
return NULL;
wpa_s->global = global;
t_iface = *iface;
if (global->params.override_driver) {
wpa_printf(MSG_DEBUG, "Override interface parameter: driver "
"('%s' -> '%s')",
iface->driver, global->params.override_driver);
t_iface.driver = global->params.override_driver;
}
if (global->params.override_ctrl_interface) {
wpa_printf(MSG_DEBUG, "Override interface parameter: "
"ctrl_interface ('%s' -> '%s')",
iface->ctrl_interface,
global->params.override_ctrl_interface);
t_iface.ctrl_interface =
global->params.override_ctrl_interface;
}
/*重要*/
if (wpa_supplicant_init_iface(wpa_s, &t_iface)) {
wpa_printf(MSG_DEBUG, "Failed to add interface %s",
iface->ifname);
wpa_supplicant_deinit_iface(wpa_s, 0, 0);
return NULL;
}
/* 通过dbus通知外接有新的iface加入 Notify the control interfaces about new iface */
if (wpas_notify_iface_added(wpa_s)) {
wpa_supplicant_deinit_iface(wpa_s, 1, 0);
return NULL;
}
/*通过dbus通知外界有新的无线网络加入*/
for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next)
wpas_notify_network_added(wpa_s, ssid);
/* wpa_global的ifaces变量指向一个wpa_supplicant对象,
* 而wpa_supplicant又通过next变量将自己链接到一个单项链表中*/
wpa_s->next = global->ifaces;
global->ifaces = wpa_s;
wpa_dbg(wpa_s, MSG_DEBUG, "Added interface %s", wpa_s->ifname);
wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
return wpa_s;
}
wpa_supplicant_add_iface函数的内容非常丰富, 包括两个重要数据结构(wpa_supplicant和wpa_ssid)以及一个关键函数wpa_supplicant_init_iface.这些数据背景较多, 先来看看他们.
wpa_ssid结构体
wpa_ssid结构体用于存储某个无线网络的配置信息(如所支持的安全类型, 优先级等). (external\wpa_supplicant_8\wpa_supplicant\wpa_supplicant.conf)文件中的每一个network项都对应一个wpa_ssid对象.
路径为:external\wpa_supplicant_8\wpa_supplicant\config_ssid.h
/**
* struct wpa_ssid - Network configuration data
*
* This structure includes all the configuration variables for a network. This
* data is included in the per-interface configuration data as an element of
* the network list, struct wpa_config::ssid. Each network block in the
* configuration is mapped to a struct wpa_ssid instance.
*
*/
struct wpa_ssid {
/**
* next - Next network in global list
*
* This pointer can be used to iterate over all networks. The head of
* this list is stored in the ssid field of struct wpa_config.
*/
struct wpa_ssid *next;/*所有wpa_ssid对象都保存在一个链表当中, 头指针保存于另外一个结构体wpa_config的ssid变量中*/
/**
* pnext - Next network in per-priority list
*
* This pointer can be used to iterate over all networks in the same
* priority class. The heads of these list are stored in the pssid
* fields of struct wpa_config.
*/
struct wpa_ssid *pnext;/*wpa_ssid还可以按priority保存在另一个链表中, 头指针为wpa_config的ssid变量*/
/**
* id - Unique id for the network
*
* This identifier is used as a unique identifier for each network
* block when using the control interface. Each network is allocated an
* id when it is being created, either when reading the configuration
* file or when a new network is added through the control interface.
*/
int id;/*每个无线网络都有一个唯一的编号*/
/**
* priority - Priority group
*
* By default, all networks will get same priority group (0). If some
* of the networks are more desirable, this field can be used to change
* the order in which wpa_supplicant goes through the networks when
* selecting a BSS. The priority groups will be iterated in decreasing
* priority (i.e., the larger the priority value, the sooner the
* network is matched against the scan results). Within each priority
* group, networks will be selected based on security policy, signal
* strength, etc.
*
* Please note that AP scanning with scan_ssid=1 and ap_scan=2 mode are
* not using this priority to select the order for scanning. Instead,
* they try the networks in the order that used in the configuration
* file.
*/
int priority;/*该无线网络对应的priority值, 默认为0*/
/**
* ssid - Service set identifier (network name)
*
* This is the SSID for the network. For wireless interfaces, this is
* used to select which network will be used. If set to %NULL (or
* ssid_len=0), any SSID can be used. For wired interfaces, this must
* be set to %NULL. Note: SSID may contain any characters, even nul
* (ASCII 0) and as such, this should not be assumed to be a nul
* terminated string. ssid_len defines how many characters are valid
* and the ssid field is not guaranteed to be nul terminated.
*/
u8 *ssid;/*无线网络的名字*/
/**
* ssid_len - Length of the SSID
*/
size_t ssid_len;/*ssid变量长度*/
/**
* bssid - BSSID
*
* If set, this network block is used only when associating with the AP
* using the configured BSSID
*
* If this is a persistent P2P group (disabled == 2), this is the GO
* Device Address.
*/
u8 bssid[ETH_ALEN];/*用于保存bssid[ETH_ALEN]*/
/**
* bssid_set - Whether BSSID is configured for this network
*/
int bssid_set;/*该无线网络是否设置了bssid变量*/
/**
* psk - WPA pre-shared key (256 bits)
*/
u8 psk[32];/*数组长度为32, 用于保存WPA中的Pre-Shared Key (256位)*/
/**
* psk_set - Whether PSK field is configured
*/
int psk_set;/*是否设置了上面的psk参数*/
/**
* passphrase - WPA ASCII passphrase
*
* If this is set, psk will be generated using the SSID and passphrase
* configured for the network. ASCII passphrase must be between 8 and
* 63 characters (inclusive).
*/
char *passphrase;/*为WPA设置ASCII字符密码*/
/**
* ext_psk - PSK/passphrase name in external storage
*
* If this is set, PSK/passphrase will be fetched from external storage
* when requesting association with the network.
*/
char *ext_psk;
/**
* pairwise_cipher - Bitfield of allowed pairwise ciphers, WPA_CIPHER_*
*/
int pairwise_cipher;/*用于单播数据加密的密钥类型*/
/**
* group_cipher - Bitfield of allowed group ciphers, WPA_CIPHER_*
*/
int group_cipher;/*用于数组数据加密的密钥类型*/
/**
* key_mgmt - Bitfield of allowed key management protocols
*
* WPA_KEY_MGMT_*
*/
int key_mgmt;/*密钥管理类型*/
/**
* bg_scan_period - Background scan period in seconds, 0 to disable, or
* -1 to indicate no change to default driver configuration
*/
int bg_scan_period;
/**
* proto - Bitfield of allowed protocols, WPA_PROTO_*
*/
int proto;/*该无线网络支持的安全保护类型*/
/**
* auth_alg - Bitfield of allowed authentication algorithms
*
* WPA_AUTH_ALG_*
*/
int auth_alg;/*该无线网络支持的身份验证类型*/
/**
* scan_ssid - Scan this SSID with Probe Requests
*
* scan_ssid can be used to scan for APs using hidden SSIDs.
* Note: Many drivers do not support this. ap_mode=2 can be used with
* such drivers to use hidden SSIDs.
*/
int scan_ssid;/*是否利用probe request帧扫描此ssid对应的无线网络*/
#ifdef IEEE8021X_EAPOL
#define EAPOL_FLAG_REQUIRE_KEY_UNICAST BIT(0)
#define EAPOL_FLAG_REQUIRE_KEY_BROADCAST BIT(1)
/**
* eapol_flags - Bit field of IEEE 802.1X/EAPOL options (EAPOL_FLAG_*)
*/
int eapol_flags;/*EAPOL选项*/
/**
* eap - EAP peer configuration for this network
*/
struct eap_peer_config eap;/*eap peer端设置信息*/
#endif /* IEEE8021X_EAPOL */
#define NUM_WEP_KEYS 4
#define MAX_WEP_KEY_LEN 16
/**
* wep_key - WEP keys
*/
u8 wep_key[NUM_WEP_KEYS][MAX_WEP_KEY_LEN];
/**
* wep_key_len - WEP key lengths
*/
size_t wep_key_len[NUM_WEP_KEYS];
/**
* wep_tx_keyidx - Default key index for TX frames using WEP
*/
int wep_tx_keyidx;
/**
* proactive_key_caching - Enable proactive key caching
*
* This field can be used to enable proactive key caching which is also
* known as opportunistic PMKSA caching for WPA2. This is disabled (0)
* by default unless default value is changed with the global okc=1
* parameter. Enable by setting this to 1.
*
* Proactive key caching is used to make supplicant assume that the APs
* are using the same PMK and generate PMKSA cache entries without
* doing RSN pre-authentication. This requires support from the AP side
* and is normally used with wireless switches that co-locate the
* authenticator.
*
* Internally, special value -1 is used to indicate that the parameter
* was not specified in the configuration (i.e., default behavior is
* followed).
*/
int proactive_key_caching;
/**
* mixed_cell - Whether mixed cells are allowed
*
* This option can be used to configure whether so called mixed cells,
* i.e., networks that use both plaintext and encryption in the same
* SSID, are allowed. This is disabled (0) by default. Enable by
* setting this to 1.
*/
int mixed_cell;
#ifdef IEEE8021X_EAPOL
/**
* leap - Number of EAP methods using LEAP
*
* This field should be set to 1 if LEAP is enabled. This is used to
* select IEEE 802.11 authentication algorithm.
*/
int leap;
/**
* non_leap - Number of EAP methods not using LEAP
*
* This field should be set to >0 if any EAP method other than LEAP is
* enabled. This is used to select IEEE 802.11 authentication
* algorithm.
*/
int non_leap;
/**
* eap_workaround - EAP workarounds enabled
*
* wpa_supplicant supports number of "EAP workarounds" to work around
* interoperability issues with incorrectly behaving authentication
* servers. This is recommended to be enabled by default because some
* of the issues are present in large number of authentication servers.
*
* Strict EAP conformance mode can be configured by disabling
* workarounds with eap_workaround = 0.
*/
unsigned int eap_workaround;
#endif /* IEEE8021X_EAPOL */
/**
* mode - IEEE 802.11 operation mode (Infrastucture/IBSS)
*
* 0 = infrastructure (Managed) mode, i.e., associate with an AP.
*
* 1 = IBSS (ad-hoc, peer-to-peer)
*
* 2 = AP (access point)
*
* 3 = P2P Group Owner (can be set in the configuration file)
*
* 4 = P2P Group Formation (used internally; not in configuration
* files)
*
* Note: IBSS can only be used with key_mgmt NONE (plaintext and
* static WEP) and key_mgmt=WPA-NONE (fixed group key TKIP/CCMP). In
* addition, ap_scan has to be set to 2 for IBSS. WPA-None requires
* following network block options: proto=WPA, key_mgmt=WPA-NONE,
* pairwise=NONE, group=TKIP (or CCMP, but not both), and psk must also
* be set (either directly or using ASCII passphrase).
*/
enum wpas_mode {
WPAS_MODE_INFRA = 0,
WPAS_MODE_IBSS = 1,
WPAS_MODE_AP = 2,
WPAS_MODE_P2P_GO = 3,
WPAS_MODE_P2P_GROUP_FORMATION = 4,
} mode;
/**
* disabled - Whether this network is currently disabled
*
* 0 = this network can be used (default).
* 1 = this network block is disabled (can be enabled through
* ctrl_iface, e.g., with wpa_cli or wpa_gui).
* 2 = this network block includes parameters for a persistent P2P
* group (can be used with P2P ctrl_iface commands)
*/
int disabled;
/**
* disabled_for_connect - Whether this network was temporarily disabled
*
* This flag is used to reenable all the temporarily disabled networks
* after either the success or failure of a WPS connection.
*/
int disabled_for_connect;
/**
* peerkey - Whether PeerKey handshake for direct links is allowed
*
* This is only used when both RSN/WPA2 and IEEE 802.11e (QoS) are
* enabled.
*
* 0 = disabled (default)
* 1 = enabled
*/
int peerkey;
/**
* id_str - Network identifier string for external scripts
*
* This value is passed to external ctrl_iface monitors in
* WPA_EVENT_CONNECTED event and wpa_cli sets this as WPA_ID_STR
* environment variable for action scripts.
*/
char *id_str;
#ifdef CONFIG_IEEE80211W
/**
* ieee80211w - Whether management frame protection is enabled
*
* This value is used to configure policy for management frame
* protection (IEEE 802.11w). 0 = disabled, 1 = optional, 2 = required.
* This is disabled by default unless the default value has been changed
* with the global pmf=1/2 parameter.
*
* Internally, special value 3 is used to indicate that the parameter
* was not specified in the configuration (i.e., default behavior is
* followed).
*/
enum mfp_options ieee80211w;
#endif /* CONFIG_IEEE80211W */
/**
* frequency - Channel frequency in megahertz (MHz) for IBSS
*
* This value is used to configure the initial channel for IBSS (adhoc)
* networks, e.g., 2412 = IEEE 802.11b/g channel 1. It is ignored in
* the infrastructure mode. In addition, this value is only used by the
* station that creates the IBSS. If an IBSS network with the
* configured SSID is already present, the frequency of the network
* will be used instead of this configured value.
*/
int frequency;
int ht40;
/**
* wpa_ptk_rekey - Maximum lifetime for PTK in seconds
*
* This value can be used to enforce rekeying of PTK to mitigate some
* attacks against TKIP deficiencies.
*/
int wpa_ptk_rekey;
/**
* scan_freq - Array of frequencies to scan or %NULL for all
*
* This is an optional zero-terminated array of frequencies in
* megahertz (MHz) to include in scan requests when searching for this
* network. This can be used to speed up scanning when the network is
* known to not use all possible channels.
*/
int *scan_freq;
/**
* bgscan - Background scan and roaming parameters or %NULL if none
*
* This is an optional set of parameters for background scanning and
* roaming within a network (ESS) in following format:
* :
*/
char *bgscan;
/**
* ignore_broadcast_ssid - Hide SSID in AP mode
*
* Send empty SSID in beacons and ignore probe request frames that do
* not specify full SSID, i.e., require stations to know SSID.
* default: disabled (0)
* 1 = send empty (length=0) SSID in beacon and ignore probe request
* for broadcast SSID
* 2 = clear SSID (ASCII 0), but keep the original length (this may be
* required with some clients that do not support empty SSID) and
* ignore probe requests for broadcast SSID
*/
int ignore_broadcast_ssid;
/**
* freq_list - Array of allowed frequencies or %NULL for all
*
* This is an optional zero-terminated array of frequencies in
* megahertz (MHz) to allow for selecting the BSS. If set, scan results
* that do not match any of the specified frequencies are not
* considered when selecting a BSS.
*/
int *freq_list;
/**
* p2p_client_list - List of P2P Clients in a persistent group (GO)
*
* This is a list of P2P Clients (P2P Device Address) that have joined
* the persistent group. This is maintained on the GO for persistent
* group entries (disabled == 2).
*/
u8 *p2p_client_list;
/**
* num_p2p_clients - Number of entries in p2p_client_list
*/
size_t num_p2p_clients;
#ifndef P2P_MAX_STORED_CLIENTS
#define P2P_MAX_STORED_CLIENTS 100
#endif /* P2P_MAX_STORED_CLIENTS */
/**
* psk_list - Per-client PSKs (struct psk_list_entry)
*/
struct dl_list psk_list;
/**
* p2p_group - Network generated as a P2P group (used internally)
*/
int p2p_group;
/**
* p2p_persistent_group - Whether this is a persistent group
*/
int p2p_persistent_group;
/**
* temporary - Whether this network is temporary and not to be saved
*/
int temporary;
/**
* export_keys - Whether keys may be exported
*
* This attribute will be set when keys are determined through
* WPS or similar so that they may be exported.
*/
int export_keys;
#ifdef ANDROID_P2P
/**
* assoc_retry - Number of times association should be retried.
*/
int assoc_retry;
#endif
#ifdef CONFIG_HT_OVERRIDES
/**
* disable_ht - Disable HT (IEEE 802.11n) for this network
*
* By default, use it if it is available, but this can be configured
* to 1 to have it disabled.
*/
int disable_ht;
/**
* disable_ht40 - Disable HT40 for this network
*
* By default, use it if it is available, but this can be configured
* to 1 to have it disabled.
*/
int disable_ht40;
/**
* disable_sgi - Disable SGI (Short Guard Interval) for this network
*
* By default, use it if it is available, but this can be configured
* to 1 to have it disabled.
*/
int disable_sgi;
/**
* disable_max_amsdu - Disable MAX A-MSDU
*
* A-MDSU will be 3839 bytes when disabled, or 7935
* when enabled (assuming it is otherwise supported)
* -1 (default) means do not apply any settings to the kernel.
*/
int disable_max_amsdu;
/**
* ampdu_factor - Maximum A-MPDU Length Exponent
*
* Value: 0-3, see 7.3.2.56.3 in IEEE Std 802.11n-2009.
*/
int ampdu_factor;
/**
* ampdu_density - Minimum A-MPDU Start Spacing
*
* Value: 0-7, see 7.3.2.56.3 in IEEE Std 802.11n-2009.
*/
int ampdu_density;
/**
* ht_mcs - Allowed HT-MCS rates, in ASCII hex: ffff0000...
*
* By default (empty string): Use whatever the OS has configured.
*/
char *ht_mcs;
#endif /* CONFIG_HT_OVERRIDES */
#ifdef CONFIG_VHT_OVERRIDES
/**
* disable_vht - Disable VHT (IEEE 802.11ac) for this network
*
* By default, use it if it is available, but this can be configured
* to 1 to have it disabled.
*/
int disable_vht;
/**
* vht_capa - VHT capabilities to use
*/
unsigned int vht_capa;
/**
* vht_capa_mask - mask for VHT capabilities
*/
unsigned int vht_capa_mask;
int vht_rx_mcs_nss_1, vht_rx_mcs_nss_2,
vht_rx_mcs_nss_3, vht_rx_mcs_nss_4,
vht_rx_mcs_nss_5, vht_rx_mcs_nss_6,
vht_rx_mcs_nss_7, vht_rx_mcs_nss_8;
int vht_tx_mcs_nss_1, vht_tx_mcs_nss_2,
vht_tx_mcs_nss_3, vht_tx_mcs_nss_4,
vht_tx_mcs_nss_5, vht_tx_mcs_nss_6,
vht_tx_mcs_nss_7, vht_tx_mcs_nss_8;
#endif /* CONFIG_VHT_OVERRIDES */
/**
* ap_max_inactivity - Timeout in seconds to detect STA's inactivity
*
* This timeout value is used in AP mode to clean up inactive stations.
* By default: 300 seconds.
*/
int ap_max_inactivity;
/**
* dtim_period - DTIM period in Beacon intervals
* By default: 2
*/
int dtim_period;
/**
* beacon_int - Beacon interval (default: 100 TU)
*/
int beacon_int;
/**
* auth_failures - Number of consecutive authentication failures
*/
unsigned int auth_failures;
/**
* disabled_until - Network block disabled until this time if non-zero
*/
struct os_time disabled_until;
/**
* parent_cred - Pointer to parent wpa_cred entry
*
* This pointer can be used to delete temporary networks when a wpa_cred
* that was used to create them is removed. This pointer should not be
* dereferences since it may not be updated in all cases.
*/
void *parent_cred;
};