iw 连接open AP失败的问题分析

---

iw 连接open AP 问题

adb shell iw dev wlan0 connect -w “ssid” “frequece” “bssid”
返回结果：
wlan0 (phy #0): failed to connect to “ssid” status: 1: Unspecified failure

iw connect 连接流程

• 首先分析并扩展一下Connect.c中的宏定义

TOPLEVEL(connect, “[-w] [] [] [key 0:abcde d:1:6162636465]”,　0, 0, CIB_NETDEV, iw_connect, “dddd.”);　　　　====>
struct cmd \
__section_connect \
__attribute__((used)) __attribute__((section(“__cmd”))) = { \
.name = (“connect”), \
.args = (“[-w] [] [] [key 0:abcde d:1:6162636465]”), \
.cmd = (0), \
.nl_msg_flags = (0), \
.idby = (CIB_NETDEV), \
.handler = (iw_connect), \
.help = (“dddd”), \
}

---

HIDDEN(connect, establish, “”, NL80211_CMD_CONNECT, 0, CIB_NETDEV, iw_conn); ====>
static struct cmd \
__cmd_establish_iw_conn_NL80211_CMD_CONNECT_CIB_NETDEV_1\
__attribute__((used)) __attribute__((section(“__cmd”))) = { \
.name = (“establish”), \
.args = (“”), \
.cmd = (NL80211_CMD_CONNECT), \
.nl_msg_flags = (0), \
.hidden = (1), \
.idby = (CIB_NETDEV), \
.handler = (iw_conn), \
.help = (NULL), \
.parent = __section_connect, \
.selector = (NULL), \
}

connect命令在iw中的流程

connect open AP在iw中的关键步骤

msg = nlmsg_alloc();
genlmsg_put(msg, 0, 0, state->nl80211_id, 0, cmd->nl_msg_flags, cmd->cmd, 0);
//establish 的cmd是：NL80211_CMD_CONNECT
NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, devidx);
NLA_PUT(msg, NL80211_ATTR_SSID, strlen(argv[0]), argv[0]);
NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_FREQ, freq);
NLA_PUT(msg, NL80211_ATTR_MAC, 6, bssid);
从代码逻辑看一切正常，没有问题呀！？，为什么连接不上呢？

正常连接logde关键步骤：

在external/wpa_supplicant_8/src/drivers/driver_nl80211.c中查看wpa_driver_nl80211_connect源码，对应log:
1. 设置cmd, ifindex:
wpa_supplicant: nl80211: Connect (ifindex=24)
2. 设置bssid, bssid_hint
wpa_supplicant: * bssid=a0:8d:16:a7:fb:4d
wpa_supplicant: * bssid_hint=a0:8d:16:a7:fb:4d
3. 设置freq, freq_hint
wpa_supplicant: * freq=2412
wpa_supplicant: * freq_hint=2412
4. 设置IEs
wpa_supplicant: * IEs - hexdump(len=8): 7f 06 00 00 0a 82 01 40
5. 设置Auth Type
wpa_supplicant: * Auth Type 0

结合iw中连接步骤，继续分析

大部分都一样，但少了一步Auth Type的设置！
试着加上这一步看看！
竟然成功连接上了：
wlan0 (phy #0): connected to a0:8d:16:a7:fb:4d， 搞定收工！