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本篇文章為大家展示了怎么解決OpenWrt無線搜索錯誤bug，內容簡明扼要并且容易理解，絕對能使你眼前一亮，通過這篇文章的詳細介紹希望你能有所收獲。
TP-LINK 841n路由更新openwrt系統(tǒng)到Barrier Breaker r41988，“網絡”-->“無線”-->“搜索”這個功能就不能用了，trunk版的也有這個問題。其實今年4、5月份玩HG255D路由就有這個問題，但當時的源碼編譯給TP-LINK 841n卻沒有這個問題。對這樣的問題，確實比較頭大，花了兩天時間終于找到bug所在（只解決wr841n的，我的hg255d出問題了）。
無線搜索bug截圖（注意device參數(shù)radio0）：
一番搜索后發(fā)現(xiàn)此頁面的源碼在系統(tǒng)的/usr/lib/lua/luci/view/admin_network/wifi_join.htm文件里，對應openwrt的源碼路徑為./feeds/luci/modules/admin-full/luasrc/view/admin_network/wifi_join.htm。終于要代碼如下：
<%-
local sys = require "luci.sys"
local utl = require "luci.util"
function guess_wifi_signal(info)
local scale = (100 / (info.quality_max or 100) * (info.quality or 0))
local icon
if not info.bssid or info.bssid == "00:00:00:00:00:00" then
icon = resource .. "/icons/signal-none.png"
elseif scale < 15 then
icon = resource .. "/icons/signal-0.png"
elseif scale < 35 then
icon = resource .. "/icons/signal-0-25.png"
elseif scale < 55 then
icon = resource .. "/icons/signal-25-50.png"
elseif scale < 75 then
icon = resource .. "/icons/signal-50-75.png"
else
icon = resource .. "/icons/signal-75-100.png"
end
return icon
end
function percent_wifi_signal(info)
local qc = info.quality or 0
local qm = info.quality_max or 0
if info.bssid and qc > 0 and qm > 0 then
return math.floor((100 / qm) * qc)
else
return 0
end
end
function format_wifi_encryption(info)
if info.wep == true then
return "WEP"
elseif info.wpa > 0 then
return translatef("<abbr title='Pairwise: %s / Group: %s'>%s - %s</abbr>",
table.concat(info.pair_ciphers, ", "),
table.concat(info.group_ciphers, ", "),
(info.wpa == 3) and translate("mixed WPA/WPA2")
or (info.wpa == 2 and "WPA2" or "WPA"),
table.concat(info.auth_suites, ", ")
)
elseif info.enabled then
return "<em>%s</em>" % translate("unknown")
else
return "<em>%s</em>" % translate("open")
end
end
local dev = luci.http.formvalue("device")
local iw = luci.sys.wifi.getiwinfo(dev)
if not iw then
luci.http.redirect(luci.dispatcher.build_url("admin/network/wireless"))
return
end
function scanlist(times)
local i, k, v
local l = { }
local s = { }
for i = 1, times do
for k, v in ipairs(iw.scanlist or { }) do
if not s[v.bssid] then
l[#l+1] = v
s[v.bssid] = true
end
end
end
return l
end
-%>
<%+header%>
<h3><a id="content" name="content"><%:Join Network: Wireless Scan%></a></h3>
<div class="cbi-map">
<fieldset class="cbi-section">
<table class="cbi-section-table" >
<!-- scan list -->
<% for i, net in ipairs(scanlist(3)) do net.encryption = net.encryption or { } %>
<tr class="cbi-section-table-row cbi-rowstyle-<%=1 + ((i-1) % 2)%>">
<td class="cbi-value-field" >
<abbr title="<%:Signal%>: <%=net.signal%> <%:dB%> / <%:Quality%>: <%=net.quality%>/<%=net.quality_max%>">
<img src="<%=guess_wifi_signal(net)%>" /><br />
<small><%=percent_wifi_signal(net)%>%</small>
</abbr>
</td>
<td class="cbi-value-field" >
<big><strong><%=net.ssid and utl.pcdata(net.ssid) or "<em>%s</em>" % translate("hidden")%></strong></big><br />
<strong>Channel:</strong> <%=net.channel%> |
<strong>Mode:</strong> <%=net.mode%> |
<strong>BSSID:</strong> <%=net.bssid%> |
<strong>Encryption:</strong> <%=format_wifi_encryption(net.encryption)%>
</td>
<td class="cbi-value-field" >
<form action="<%=REQUEST_URI%>" method="post">
<input type="hidden" name="device" value="<%=utl.pcdata(dev)%>" />
<input type="hidden" name="join" value="<%=utl.pcdata(net.ssid)%>" />
<input type="hidden" name="mode" value="<%=net.mode%>" />
<input type="hidden" name="bssid" value="<%=net.bssid%>" />
<input type="hidden" name="channel" value="<%=net.channel%>" />
<input type="hidden" name="wep" value="<%=net.encryption.wep and 1 or 0%>" />
<% if net.encryption.wpa then %>
<input type="hidden" name="wpa_version" value="<%=net.encryption.wpa%>" />
<% for _, v in ipairs(net.encryption.auth_suites) do %><input type="hidden" name="wpa_suites" value="<%=v%>" />
<% end; for _, v in ipairs(net.encryption.group_ciphers) do %><input type="hidden" name="wpa_group" value="<%=v%>" />
<% end; for _, v in ipairs(net.encryption.pair_ciphers) do %><input type="hidden" name="wpa_pairwise" value="<%=v%>" />
<% end; end %>
<input type="hidden" name="clbridge" value="<%=iw.type == "wl" and 1 or 0%>" />
<input class="cbi-button cbi-button-apply" type="submit" value="<%:Join Network%>" />
</form>
</td>
</tr>
<% end %>
<!-- /scan list -->
</table>
</fieldset>
</div>進一步的測試發(fā)現(xiàn)，在調用function scanlist(times)異常導致生成的網頁不完整，瀏覽器就會看到那段錯誤信息。而此函數(shù)又是在調用iw.scanlist發(fā)生異常。由local iw = luci.sys.wifi.getiwinfo(dev)找到sys.lua模塊，路徑/usr/lib/lua/luci/sys.lua，對應openwrt源碼位置./feeds/luci/modules/base/luasrc/sys.lua。主要源碼：
--- Get wireless information for given interface.
-- @param ifname String containing the interface name
-- @return A wrapped iwinfo object instance
function wifi.getiwinfo(ifname)
local stat, iwinfo = pcall(require, "iwinfo")
if ifname then
local c = 0
local u = uci.cursor_state()
local d, n = ifname:match("^(%w+)%.network(%d+)")
if d and n then
ifname = d
n = tonumber(n)
u:foreach("wireless", "wifi-iface",
function(s)
if s.device == d then
c = c + 1
if c == n then
ifname = s.ifname or s.device
return false
end
end
end)
elseif u:get("wireless", ifname) == "wifi-device" then
u:foreach("wireless", "wifi-iface",
function(s)
if s.device == ifname and s.ifname then
ifname = s.ifname
return false
end
end)
end
local t = stat and iwinfo.type(ifname)
local x = t and iwinfo[t] or { }
return setmetatable({}, {
__index = function(t, k)
if k == "ifname" then
return ifname
elseif x[k] then
return x[k](ifname)
end
end
})
end
end原來是調用iwinfo命令完成的無線搜索。在openwrt下運行iwinfo命令：
root@OpenWrt:~# iwinfo --help Usage: iwinfo <device> info iwinfo <device> scan iwinfo <device> txpowerlist iwinfo <device> freqlist iwinfo <device> assoclist iwinfo <device> countrylist root@OpenWrt:~# iwinfo radio0 scan Cell 01 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 02 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 03 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 04 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 05 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 06 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 07 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 08 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 09 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 10 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 11 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 12 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 13 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 14 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 15 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 16 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 17 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 18 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 19 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none Cell 20 - Address: 00:00:00:00:00:00 ESSID: unknown Mode: Unknown Channel: unknown Signal: -256 dBm Quality: 0/0 Encryption: none
看看Address、ESSID。。 說明iwinfo根本就無法掃描到無線接入點。而在4、5月份編譯的版本運行此命令沒問題，可以搜索到接入點。iwinfo涉及到兩個文件，在openwrt系統(tǒng)下一個是可執(zhí)行文件/usr/bin/iwinfo，另一個是動態(tài)鏈接庫文件/usr/lib/libiwinfo.so。于是拷貝之前系統(tǒng)（可以用搜索功能）的iwinfo、libiwinfo.so文件到有問題的路由的/tmp目錄下，shell切換到/tmp目錄，執(zhí)行export LD_LIBRARY_PATH=.
然后再執(zhí)行./iwinfo radio0 scan，發(fā)現(xiàn)搜索無線接入點正常，看來出來就出在iwinfo、libiwinfo.so上。直接刪除/tmp目錄下的libiwinfo.so后再./iwinfo radio0 scan，問題又出現(xiàn)了。由此推斷出問題應該在libiwinfo.so里。iwinfo工具源碼在openwrt源碼的./package/network/utils/iwinfo下，注意Makefile文件有如下代碼：
IWINFO_BACKENDS := \ $(if $(CONFIG_PACKAGE_kmod-brcm-wl),wl) \ $(if $(CONFIG_PACKAGE_kmod-brcm-wl-mini),wl) \ $(if $(CONFIG_PACKAGE_kmod-brcm-wl-mimo),wl) \ $(if $(CONFIG_PACKAGE_kmod-madwifi),madwifi) \ $(if $(CONFIG_PACKAGE_kmod-mac80211),nl80211)
在src目錄下的Makefile文件有如下代碼：
ifneq ($(filter wl,$(IWINFO_BACKENDS)),) IWINFO_CFLAGS += -DUSE_WL IWINFO_LIB_OBJ += iwinfo_wl.o endif ifneq ($(filter madwifi,$(IWINFO_BACKENDS)),) IWINFO_CFLAGS += -DUSE_MADWIFI IWINFO_LIB_OBJ += iwinfo_madwifi.o endif ifneq ($(filter nl80211,$(IWINFO_BACKENDS)),) IWINFO_CFLAGS += -DUSE_NL80211 IWINFO_CLI_LDFLAGS += -lnl-tiny IWINFO_LIB_LDFLAGS += -lnl-tiny IWINFO_LIB_OBJ += iwinfo_nl80211.o endif
無線搜索有3中實現(xiàn)，剛開始我也不知道841n下是用哪種，索性在makefile文件里寫些調試輸出語句。然后make package/network/utils/iwinfo/compile V=s重新編譯iwinfo，發(fā)現(xiàn)用的是nl80211，也就是說要改的代碼在./src/iwinfo_nl80211.c。經過一系列的調試最終發(fā)現(xiàn)bug所在。解決方案如下：
// iwinfo_cli.c文件
static void print_scanlist(const struct iwinfo_ops *iw, const char *ifname)
{
int i, x, len=0; //這里len必須初始化為0
char buf[IWINFO_BUFSIZE];
struct iwinfo_scanlist_entry *e;
if (iw->scanlist(ifname, buf, &len))
{
printf("Scanning not possible\n\n");
return;
}
else if (len <= 0)
{
printf("No scan results\n\n");
return;
}// iwinfo_nl80211.c文件nl80211_phy2ifname函數(shù)修改如下
static char * nl80211_phy2ifname(const char *ifname)
{
int fd, ifidx = -1, cifidx = -1, phyidx = -1;
char buffer[64];
static char nif[IFNAMSIZ] = { 0 };//注意靜態(tài)變量
DIR *d;
struct dirent *e;
char *ret = NULL; //添加
if (!ifname)
return NULL;
else if (!strncmp(ifname, "phy", 3))
phyidx = atoi(&ifname[3]);
else if (!strncmp(ifname, "radio", 5))
phyidx = atoi(&ifname[5]);
//當傳進來的ifname=wlan0時，phyidx=-1，后面的memset可能會把ifname清空。
//memset(nif, 0, sizeof(nif)); //注釋掉，因為ifname可能指向nif
if (phyidx > -1)
{
if ((d = opendir("/sys/class/net")) != NULL)
{
while ((e = readdir(d)) != NULL)
{
snprintf(buffer, sizeof(buffer),
"/sys/class/net/%s/phy80211/index", e->d_name);
if (nl80211_readint(buffer) == phyidx)
{
snprintf(buffer, sizeof(buffer),
"/sys/class/net/%s/ifindex", e->d_name);
if ((cifidx = nl80211_readint(buffer)) >= 0 &&
((ifidx < 0) || (cifidx < ifidx)))
{
ifidx = cifidx;
strncpy(nif, e->d_name, sizeof(nif));
ret = nif ; //添加
break ; //添加
}
}
}
closedir(d);
}
}
return ret ; //修改
}make package/network/utils/iwinfo/compile V=s 重新編譯iwinfo，傳到路由上測試，iwinfo radio0 scan已經沒問題，可以正常搜索無線了。其實我不喜歡nl80211_phy2ifname函數(shù)用靜態(tài)變量方式返回，而更傾向于用函數(shù)參數(shù)的方式，例如聲明成static char * nl80211_phy2ifname(const char *ifname, char *out)。
上述內容就是怎么解決OpenWrt無線搜索錯誤bug，你們學到知識或技能了嗎？如果還想學到更多技能或者豐富自己的知識儲備，歡迎關注億速云行業(yè)資訊頻道。
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