Android wpa_supplicant源码分析--conf配置文件

http://blog.csdn.net/cuijiyue/article/details/51428835

1 配置文件

conf文件作为wpa_supplicant的配置文件，一般叫做 wpa_supplicant.conf 。其中存储着wpa_supplicant的运行参数和以保存的网络列表。
conf文件的路径，通过启动wpa_supplicant时的 –c 参数传入，初始化过程中赋值到wpa_s->confname，然后将数据读入wpa_s->conf中。

wpa_supplicant的所有参数都定义在struct wpa_config中

struct wpa_config {    //config文件中，存储所有network节点的链表    struct wpa_ssid *ssid;    //按照priority排列的network节点    struct wpa_ssid **pssid;    //*pssid的长度    int num_prio;    /**     * cred - Head of the credential list     *     * This is the head for the list of all the configured credentials.     */    struct wpa_cred *cred;    //EAP版本，WPAS支持到2    int eapol_version;    //1---wpas负责扫描和选择网络    //0、2---驱动负责扫描和连接    int ap_scan;    //bgscan - Background scan and roaming parameters or %NULL if none    char *bgscan;    //disable_scan_offload - Disable automatic offloading of scan requests    //驱动可以自行sche_scan，设置为1，disable驱动的功能    int disable_scan_offload;    // ctrl_interface - Parameters for the control interface    //结构名称例如wlan0    char *ctrl_interface;    //ctrl_interface_group - Control interface group (DEPRECATED)    char *ctrl_interface_group;    //fast_reauth - EAP fast re-authentication (session resumption)    //默认是1 disable，设置为0 disable该功能，    int fast_reauth;    //opensc_engine_path - Path to the OpenSSL engine for opensc        char *opensc_engine_path;    //pkcs11_engine_path - Path to the OpenSSL engine for PKCS#11    char *pkcs11_engine_path;    //pkcs11_module_path - Path to the OpenSSL OpenSC/PKCS#11 module    char *pkcs11_module_path;    //pcsc_reader - PC/SC reader name prefix    char *pcsc_reader;    // pcsc_pin - PIN for USIM, GSM SIM, and smartcards    char *pcsc_pin;    //external_sim - Use external processing for SIM/USIM operations    int external_sim;    //driver_param - Driver interface parameters    //如果有的话，通过struct wpa_driver_ops::set_param()执行    char *driver_param;    //dot11RSNAConfigPMKLifetime - Maximum lifetime of a PMK    unsigned int dot11RSNAConfigPMKLifetime;    // dot11RSNAConfigPMKReauthThreshold - PMK re-authentication threshold    unsigned int dot11RSNAConfigPMKReauthThreshold;    //dot11RSNAConfigSATimeout - Security association timeout    unsigned int dot11RSNAConfigSATimeout;    //update_config - Is wpa_supplicant allowed to update configuration/    int update_config;    //blobs - Configuration blobs    struct wpa_config_blob *blobs;    // uuid - Universally Unique IDentifier (UUID; see RFC 4122) for WPS    u8 uuid[16];    //device_name - Device Name (WPS)    char *device_name;    //manufacturer - Manufacturer (WPS)    //The manufacturer of the device (up to 64 ASCII characters)    char *manufacturer;    // model_name - Model Name (WPS)    //Model of the device (up to 32 ASCII characters)    char *model_name;    //model_number - Model Number (WPS)    //Additional device description (up to 32 ASCII characters)    char *model_number;    //serial_number - Serial Number (WPS)    //Serial number of the device (up to 32 characters)    char *serial_number;    //device_type - Primary Device Type (WPS)    u8 device_type[WPS_DEV_TYPE_LEN];    //config_methods - Config Methods（WPS）    char *config_methods;    //os_version - OS Version (WPS)    //4-octet operating system version number    u8 os_version[4];    //country - Country code（ISO/IEC alpha2）    char country[2];    /**     * wps_cred_processing - Credential processing     *     *   0 = process received credentials internally     *   1 = do not process received credentials; just pass them over     *  ctrl_iface to external program(s)     *   2 = process received credentials internally and pass them over     *  ctrl_iface to external program(s)     */    int wps_cred_processing;#define MAX_SEC_DEVICE_TYPES 5    /**     * sec_device_types - Secondary Device Types (P2P)     */    u8 sec_device_type[MAX_SEC_DEVICE_TYPES][WPS_DEV_TYPE_LEN];    int num_sec_device_types;    int p2p_listen_reg_class;    int p2p_listen_channel;    int p2p_oper_reg_class;    int p2p_oper_channel;    int p2p_go_intent;    char *p2p_ssid_postfix;    int persistent_reconnect;    int p2p_intra_bss;    unsigned int num_p2p_pref_chan;    struct p2p_channel *p2p_pref_chan;    struct wpa_freq_range_list p2p_no_go_freq;    int p2p_add_cli_chan;    int p2p_ignore_shared_freq;    int p2p_optimize_listen_chan;    struct wpabuf *wps_vendor_ext_m1;    //wps_vendor_ext - Vendor extension attributes in WPS    //MAX_WPS_VENDOR_EXT = 10    struct wpabuf *wps_vendor_ext[MAX_WPS_VENDOR_EXT];    // p2p_group_idle - Maximum idle time in seconds for P2P group    //超过该时间（秒），将关闭数据    int p2p_group_idle;    //p2p_passphrase_len - Passphrase length (8..63) for P2P GO    //GO产生的随机秘钥的长度（8~63）    unsigned int p2p_passphrase_len;    //bss_max_count - Maximum number of BSS entries to keep in memory    //存储的bss最大个数    unsigned int bss_max_count;    //bss_expiration_age - BSS entry age after which it can be expired    //bss超期时间秒（bss 被remnove后的时间），    unsigned int bss_expiration_age;    //bss_expiration_scan_count - Expire BSS after number of scans    //bss经过几次扫描不到，被remove    unsigned int bss_expiration_scan_count;    //filter_ssids - SSID-based scan result filtering    //0--disable， 1--enable    int filter_ssids;    //filter_rssi - RSSI-based scan result filtering    //0--disable, -n--去掉scan_res中<-ndb的bss    int filter_rssi;    //max_num_sta - Maximum number of STAs in an AP/P2P GO    unsigned int max_num_sta;    // freq_list - Array of allowed scan frequencies or %NULL for all    //允许扫描的频率列表    int *freq_list;    //scan_cur_freq - Whether to scan only the current channel,只扫描当前频率    int scan_cur_freq;    //changed_parameters - Bitmap of changed parameters since last update    unsigned int changed_parameters;    //disassoc_low_ack - Disassocicate stations with massive packet loss    //因丢包导致关联失败的station个数    int disassoc_low_ack;    //interworking - Whether Interworking (IEEE 802.11u) is enabled    int interworking;    //access_network_type - Access Network Type    //interworking=1时，该项起作用，取值0~15    int access_network_type;    //hessid - Homogenous ESS identifier 80211u相关    u8 hessid[ETH_ALEN];    //hs20 - Hotspot 2.0    int hs20;    //pbc_in_m1 - AP mode WPS probing workaround for PBC with Windows 7    int pbc_in_m1;    //autoscan - Automatic scan parameters or %NULL if none，文档中有介绍    //<autoscan module name>:<module parameters>    char *autoscan;    //NFC相关    int wps_nfc_pw_from_config;    int wps_nfc_dev_pw_id;    struct wpabuf *wps_nfc_dh_pubkey;    struct wpabuf *wps_nfc_dh_privkey;    struct wpabuf *wps_nfc_dev_pw;    /**     * ext_password_backend - External password backend or %NULL if none     *     * format: <backend name>[:<optional backend parameters>]     */    char *ext_password_backend;    /*     * p2p_go_max_inactivity - Timeout in seconds to detect STA inactivity     *     * This timeout value is used in P2P GO mode to clean up     * inactive stations.     * By default: 300 seconds.     */    int p2p_go_max_inactivity;    struct hostapd_wmm_ac_params wmm_ac_params[4];    // auto_interworking - Whether to use network selection automatically    int auto_interworking;    //p2p_go_ht40 - Default mode for HT40 enable when operating as GO.    int p2p_go_ht40;    // p2p_go_vht - Default mode for VHT enable when operating as GO    int p2p_go_vht;    int p2p_disabled;    //p2p_no_group_iface - Whether group interfaces can be used    int p2p_no_group_iface;    //okc - Whether to enable opportunistic key caching by default    int okc;    //pmf - Whether to enable/require PMF by default。默认值为0    //ieee80211w=1 or ieee80211w=2 parameter. pmf=1/2 can be used to change    enum mfp_options pmf;    //sae_groups - Preference list of enabled groups for SAE    int *sae_groups;    // dtim_period - Default DTIM period in Beacon intervals    int dtim_period;    // beacon_int - Default Beacon interval in TU    int beacon_int;    //ap_vendor_elements: Vendor specific elements for Beacon/ProbeResp    struct wpabuf *ap_vendor_elements;    //ignore_old_scan_res - Ignore scan results older than request    int ignore_old_scan_res;    //sched_scan_interval -  schedule scan interval    unsigned int sched_scan_interval;    //tdls_external_control - External control for TDLS setup requests    int tdls_external_control;    u8 ip_addr_go[4];    u8 ip_addr_mask[4];    u8 ip_addr_start[4];    u8 ip_addr_end[4];    //osu_dir - OSU provider information directory    char *osu_dir;    //wowlan_triggers - Wake-on-WLAN triggers    char *wowlan_triggers;    //p2p_search_delay - Extra delay between concurrent search iterations    unsigned int p2p_search_delay;    //key_mgmt_offload - Use key managment offload    int key_mgmt_offload;};

2. network节点

conf文件中每一个network节点都是一个保存的网络，在Android手机扫描结果界面中可以直接点击连接该网络，形式如下
network={
ssid=”ASUS”
psk=”**”
key_mgmt=WPA-PSK
priority=6
}
上述节点中存储了网络的名称（ssid），密码（psk），加密方式（WPA_PSK），优先级（priority）
WIFI网络有多种加密方式，每种加密方式（wpa_psk，wep，open，wapi，各种eap等）的节点书写方式都不同，具体可以参考源代码中wpa_supplicant.conf文件
wpa_supplicant.conf

每一个network节点解析后会生成一个struct wpa_ssid，结构体中顶一个多种字段，以满足不同加密方式的需求。

//wpa_supplicant.conf中的网络节点都会生成一个wps_ssid的结构体struct wpa_ssid{    //链表指针，链表头存放在struct wpa_config->ssid    struct wpa_ssid *next;    //按照priority组成的链表，链表头在struct wpa_config->pssid    struct wpa_ssid *pnext;    //每个网络节点都会有一个id，当通过control interface创建时，通过config文件读取时，都会赋予一个id    int id;    //每个network初始的priority的值是0，当select该bss时，priority会升高    //收到扫描结果时，按照priority由高到低匹配，    //当priority相同时，会按照安全协议，信号强度匹配    //注意：AP采用scan_ssid=1 和 ap_scan=2 时，按照config文件中的顺序（wpa_config->ssid）匹配    int priority;    //网络标识，可以包含任何字符，    u8 *ssid;    size_t ssid_len;    //如果有该值，是该bssid的AP关联时会用到    //如果disabled == 2，该值为GO的mac    u8 bssid[ETH_ALEN];    //对于该network，bssid是否被配置    int bssid_set;    //GO的mac地址    u8 go_p2p_dev_addr[ETH_ALEN];    //psk - WPA pre-shared key (256 bits)通过passphrase项的sha生成    u8 psk[32];    //Whether PSK field is configured    int psk_set;    //如果包含该项，那么连接时采用ssid和passphrase，长度为8~63字符    char *passphrase;    //存储PSK的文件路径    char *ext_psk;    //pairwise_cipher - Bitfield of allowed pairwise ciphers, WPA_CIPHER_*    int pairwise_cipher;    //group_cipher - Bitfield of allowed group ciphers, WPA_CIPHER_*    int group_cipher;    //Bitfield of allowed key management protocols WPA_KEY_MGMT_*    int key_mgmt;    //背景扫描的间隔（秒），0----disable， -1----使用驱动中默认值    int bg_scan_period;    //Bitfield of allowed protocols, WPA_PROTO_*    int proto;    //Bitfield of allowed authentication algorithms（算法）WPA_AUTH_ALG_*    int auth_alg;    //放BSS设置为隐藏时，使用该项值写入到Probe Requests，    //当某些驱动不支持扫描隐藏网络时，设置ap_mode=2    int scan_ssid;    **EAP相关    //Bit field of IEEE 802.1X/EAPOL options (EAPOL_FLAG_*)    int eapol_flags;    //eap - EAP peer configuration for this network    struct eap_peer_config eap;    **WEP相关    //wep密码 NUM_WEP_KEYS=4 MAX_WEP_KEY_LEN=16    u8 wep_key[NUM_WEP_KEYS][MAX_WEP_KEY_LEN];    size_t wep_key_len[NUM_WEP_KEYS];    //wep_tx_keyidx - Default key index for TX frames using WEP    int wep_tx_keyidx;    //什么是proactive key caching？    //1---使能， 0--禁用    //与 PMK， PMKSA， RSN有关    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    //LEAP是一种EAP认证，android wifi界面不支持    int leap;    //non_leap - Number of EAP methods not using LEAP    int non_leap;    //eap_workaround - EAP workarounds enabled    //跳过关联失败的eap server    unsigned int eap_workaround;#endif /* IEEE8021X_EAPOL */    //WPAS模式    enum wpas_mode {        WPAS_MODE_INFRA = 0,                //征程station模式        WPAS_MODE_IBSS = 1,                 //IBSS网络，只用station不需要AP组成        WPAS_MODE_AP = 2,                   //AP， softap        WPAS_MODE_P2P_GO = 3,               //P2P GO        WPAS_MODE_P2P_GROUP_FORMATION = 4,  //不能通过config文件设置    } mode;    //0---该network可用    //1---该network不可用，可通过 ctrl_iface启用    //2---该network包含P2P参数    int disabled;    //WPS网络连接之前，设置该值disable，连接完，取消，    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    char *id_str;#ifdef CONFIG_IEEE80211W    //ieee80211w - Whether management frame protection is enabled    enum mfp_options ieee80211w;    {        NO_MGMT_FRAME_PROTECTION = 0,        MGMT_FRAME_PROTECTION_OPTIONAL = 1,        MGMT_FRAME_PROTECTION_REQUIRED = 2,    };#endif /* CONFIG_IEEE80211W */    int frequency;    int ht40;    int vht;    //wpa_ptk_rekey - Maximum lifetime for PTK in seconds    //PSK生存时间    int wpa_ptk_rekey;    //该network的扫描频率，如果设置了该值，对于该network，只扫描该频率    int *scan_freq;    //bgscan 背景扫描设置，参数格式：    //<bgscan module name>:<module parameters>    char *bgscan;    //wpas 在 AP模式时，设置隐藏SSID    //0--disable， 1--beacon中ssid长度为0，不对probe request做回应， 2 beacon中ssid内容为‘0’，不对probe request做回应    int ignore_broadcast_ssid;    //如果设置了该项，当接收到扫描结果时，如果频率列表不配皮，不在select该bss    int *freq_list;    //p2p_client_list - List of P2P Clients in a persistent group (GO)    //GC的mac地址列表    u8 *p2p_client_list;    //num_p2p_clients - Number of entries in p2p_client_list    size_t num_p2p_clients;#define P2P_MAX_STORED_CLIENTS 100    //struct psk_list_entry) 链表头    struct dl_list psk_list;    struct psk_list_entry {        struct dl_list list;        u8 addr[ETH_ALEN];        u8 psk[32];        u8 p2p;    };    //p2p_group - Network generated as a P2P group (config文件不可配置)    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    int export_keys;#ifdef CONFIG_HT_OVERRIDES    //disable_ht - Disable HT （高吞吐率模式）(IEEE 802.11n) for this network    int disable_ht;    //disable_ht40 - Disable HT40 for this network    int disable_ht40;    //disable_sgi - Disable SGI（帧间隔） (Short Guard Interval) for this network    int disable_sgi;    //disable_ldpc - Disable LDPC（一种编码方式） for this network    int disable_ldpc;    //ht40_intolerant（不容许） - Indicate 40 MHz intolerant for this network    int ht40_intolerant;    //disable_max_amsdu - Disable MAX A-MSDU    //MSDU一个报文，disable该项，amsdu为3839B，enable则为7935B，    //-1则不做任何设置    int disable_max_amsdu;    //ampdu_factor - Maximum A-MPDU Length Exponen    //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 （束波成型）(IEEE 802.11ac) for this network*/    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;    AP模式    /* dtim_period - DTIM period in Beacon intervals     * dtim，间隔多个beacon帧中包含tim信息，tim用于通知station AP有其暂存帧     * 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_reltime disabled_until;    void *parent_cred;    int macsec_policy;    //HS20相关，    int update_identifier;    unsigned int wps_run;}

3. 操作方法

在conf文件中，可以定义3种节点，
wpa_ssid 对应 network ={ }节点：
wpa_cred 对应 cred = { }节点
wpa_config_blob 对应参数blob-base64-，
主要介绍wpas_ssid（network ={ }）的作用，其余两个android还没见过
在conf文件中，是按照 项=值 的对应关系对应的，
network ={ }中的项和值得对应关系存储在全局变量数组ssid_fields中
其余的全局设置项存储在global_fields中

3.1 wpa_config_read读取参数

//name----conf文件的路径//cfgp----之前的config数据//有两个全局数组比较重要， ssid_fields存放network节点的所有可设置值， global_fields存放搜有conf中全局的可设置项struct wpa_config * wpa_config_read(const char *name, struct wpa_config *cfgp){       //buf存放conf中一行的数据，最长不能超过512    char buf[512], *pos;    //生成一个空的config结构体，里面有一些参数提前设置好默认值    struct wpa_config *config = wpa_config_alloc_empty(NULL, NULL);    //打开文件    FILE *f = fopen(name, "r");    //循环获取文件中一行    while (wpa_config_get_line(buf, sizeof(buf), f, &line, &pos)) {        //network={        if (os_strcmp(pos, "network={") == 0) {            //检测到"network={"，进一步读取网络节点的内容            struct wpa_ssid *ssid = wpa_config_read_network(f, &line, id++);                {                    //设置网络节点中一些参数的默认值                    wpa_config_set_network_defaults(ssid);                    //获取每一行的内容，通过‘=’匹配，前面是项名称，后是值                    while (wpa_config_get_line(buf, sizeof(buf), f, line, &pos)) {                        //int wpa_config_set(struct wpa_ssid *ssid, const char *var, const char *value, int line)                        //ssid中对应项的值，ssid_fields全局数组中，定义了每一项的name，获取值方式                        wpa_config_set(ssid, pos, pos2, *line)                    }                    //获取完一个network，对内部的信息进行升级                    //1.如果设置了passphrase和psk_set，利用sha1生成wpa psk                     wpa_config_validate_network(ssid, *line);                }                       //将生成的ssid加入到conf->pssid链表中            wpa_config_add_prio_network(config, ssid)        }         //cred={        else if (os_strcmp(pos, "cred={") == 0) {            cred = wpa_config_read_cred(f, &line, cred_id++);        }        //blob-base64-        else if (os_strncmp(pos, "blob-base64-", 12) == 0) {            if (wpa_config_process_blob(config, f, &line, pos + 12)        }        //获取conf中的全局参数，存储在全局数组global_fields        else if (wpa_config_process_global(config, pos, line) < 0) {        }    }}

3.2 wpa_config_write写入参数

int wpa_config_write(const char *name, struct wpa_config *config){    FILE *f;    //写入全局项    wpa_config_write_global(f, config);    //写入cred节点    for (cred = config->cred; cred; cred = cred->next) {        wpa_config_write_cred(f, cred);    }    //存储network节点    for (ssid = config->ssid; ssid; ssid = ssid->next) {        if (ssid->key_mgmt == WPA_KEY_MGMT_WPS || ssid->temporary)            continue; /* do not save temporary networks */        if (wpa_key_mgmt_wpa_psk(ssid->key_mgmt) && !ssid->psk_set && !ssid->passphrase)            continue; /* do not save invalid network */        wpa_config_write_network(f, ssid);    }    //写入blob值    for (blob = config->blobs; blob; blob = blob->next) {        ret = wpa_config_write_blob(f, blob);    }}

3.3 wpa_config_add_network添加网络

调用该函数后，会返回一个预先设置好id的ssid指针

struct wpa_ssid * wpa_config_add_network(struct wpa_config *config){    //遍历得到config->ssid中最大的id + 1    //生成一个空的ssid节点，并添加到config->ssid链表中    ssid->id = id;    //更新pssid链表    wpa_config_update_prio_list(config);    return ssid;}

• wpa_config_get_network获取一个network节点

通过id值获取conf->ssid链表的中network元素

struct wpa_ssid * wpa_config_get_network(struct wpa_config *config, int id){   struct wpa_ssid *ssid = config->ssid;    while (ssid) {        if (id == ssid->id)            break;}

3.4wpa_config_remove_network删除一个network节点

通过id值删除network

int wpa_config_remove_network(struct wpa_config *config, int id){    //通过获取config->ssid链表中id值匹配的ssid元素    struct wpa_ssid *ssid = config->ssid;    while (ssid) {        if (id == ssid->id)            break;    }    //从链表中删除    //更新pssid列表    wpa_config_update_prio_list(config);    //释放空间    wpa_config_free_ssid(ssid);}

3.5wpa_config_set设置network中某项的值

//由外部控制 framework或者wpa_cliint wpa_config_set(struct wpa_ssid *ssid, const char *var, const char *value, int line);