Android AOSP SIOCADDRT ioctl 調用失敗：網絡無法訪問

Question

AOSP：Android Pie (android-9.0.0_r16)

版本：PQ1A.181105.017.A1

設備：像素 2

我正在嘗試使用 dhcptool（重命名為 dhcpdbg）和 Android 9 Pie 在 RNDIS 模式下連接蜂窩調制解調器。 相同的設置適用於以前版本的 android，但對於 Pie，它在 ioctl(3, SIOCADDRT, 0x7ffb9b8030) 上失敗。 它說“網絡無法訪問”。

我已經檢查了 ifconfig 中的端口 ie usb0，它枚舉正確，但 dhcpdbg 調用失敗並且網絡無法 ping 通。

設備上的 Sepolicy 處於許可模式。 此外，dmesg 日志中沒有權限或其他錯誤。 注意：默認情況下，Android Pie 內核中未配置 RNDIS 驅動程序，因此我們在內核中啟用了 RNDIS 模式並在 AOSP 源中集成了更改的內核。

這是來自“strace dhcpdbg usb0”的一些日志

ioctl(3, SIOCGIFFLAGS, {ifr_name="usb0", ifr_flags=IFF_UP|IFF_BROADCAST|IFF_RUNNING|IFF_MULTICAST}) = 0
ioctl(3, SIOCSIFFLAGS, {ifr_name="usb0", ifr_flags=IFF_UP|IFF_BROADCAST|IFF_RUNNING|IFF_MULTICAST}) = 0
ioctl(3, SIOCSIFADDR, {ifr_name="usb0", ifr_addr={sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("192.168.1.100")}}) = 0
ioctl(3, SIOCSIFNETMASK, {ifr_name="usb0", ifr_netmask={sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("255.255.255.0")}}) = 0
ioctl(3, SIOCADDRT, 0x7ffb9b8030)       = -1 ENETUNREACH (Network is unreachable)
close(3)                                = 0
getuid()                                = 0
writev(5, [{iov_base="\0\355\25o\6X\\=\267\254%", iov_len=11}, {iov_base="\3", iov_len=1}, {iov_base="DHCP\0", iov_len=5}, {iov_base="failed to set default         route 192."..., iov_len=65}], 4) = 82
getuid()                                = 0
writev(6, [{iov_base="lY\0\0\0\355\25", iov_len=7}, {iov_base="\0\355\25o\6X\\=\267\254%", iov_len=11}, {iov_base="\3", iov_len=1}, {iov_base="DHCP\0",     iov_len=5}, {iov_base="failed to set default route 192ioctl(3, SIOCADDRT, 0x7ffb9b8030)."..., iov_len=65}], 5) = 89
write(2, "dhcpdbg: ", 9dhcpdbg: )                = 9
write(2, "dhcptool usb0: do_dhcp failed", 29dhcptool usb0: do_dhcp failed) = 29
write(2, ": ", 2: )                       = 2
write(2, "Network is unreachable\n", 23Network is unreachable
) = 23
mprotect(0x6ffbc65000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x6ffbc65000, 4096, PROT_READ) = 0
mprotect(0x6ffbc65000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x6ffbc65000, 4096, PROT_READ) = 0
mprotect(0x6ffbc65000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x6ffbc65000, 4096, PROT_READ) = 0
munmap(0x6ffbc65000, 4096)              = 0
exit_group(101)                         = ?
+++ exited with 101 +++

以下是網絡命令的一些輸出：

如果配置：

usb0      Link encap:Ethernet  HWaddr 02:06:06:15:00:0b  Driver rndis_host
      inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0 
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:4 errors:0 dropped:0 overruns:0 frame:0 
      TX packets:80 errors:0 dropped:0 overruns:0 carrier:0 
      collisions:0 txqueuelen:1000 
      RX bytes:1312 TX bytes:25155 

ip 添加顯示：

28: usb0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 1000
    link/ether 02:06:06:15:00:0b brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.100/24 brd 192.168.1.255 scope global usb0
    valid_lft forever preferred_lft forever

ip路由顯示：

192.168.1.0/24 dev usb0 proto kernel scope link src 192.168.1.100 
192.168.43.0/24 dev wlan0 proto kernel scope link src 192.168.43.222 

內核IP路由表：

Destination Gateway     Genmask     Flags   MSS Window  irtt Iface
192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0 usb0
192.168.43.0    0.0.0.0         255.255.255.0   U         0 0          0 wlan0

平 8.8.8.8：

connect: Network is unreachable

這個 dhcptool 工具在 Android 8 之前的所有早期 android 版本上都可以正常工作。以下是運行在同一 usb0 端口上的 Android 8 dhcptool 的工作 strace 日志。

ioctl(3, SIOCGIFFLAGS, {ifr_name="usb0", ifr_flags=IFF_UP|IFF_BROADCAST|IFF_RUNNING|IFF_MULTICAST}) = 0
ioctl(3, SIOCSIFFLAGS, {ifr_name="usb0", ifr_flags=IFF_UP|IFF_BROADCAST|IFF_RUNNING|IFF_MULTICAST}) = 0
ioctl(3, SIOCSIFADDR, {ifr_name="usb0", ifr_addr={sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("192.168.1.100")}}) = 0
ioctl(3, SIOCSIFNETMASK, {ifr_name="usb0", ifr_netmask={sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("255.255.255.0")}}) = 0
ioctl(3, SIOCADDRT, 0x7fd2bb6cd0)       = 0
close(3)                                = 0
socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0) = 3
connect(3, {sa_family=AF_UNIX, sun_path="/dev/socket/property_service"}, 31) = 0
writev(3, [{iov_base="\1\0\2\0", iov_len=4}, {iov_base="\r\0\0\0", iov_len=4}, {iov_base="net.usb0.dns1", iov_len=13}, {iov_base="\v\0\0\0", iov_len=4}, {iov_base="192.168.1.1", iov_len=11}], 5) = 36
recvfrom(3, "\0\0\0\0", 4, MSG_WAITALL, NULL, NULL) = 4
close(3)                                = 0
socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0) = 3
connect(3, {sa_family=AF_UNIX, sun_path="/dev/socket/property_service"}, 31) = 0
writev(3, [{iov_base="\1\0\2\0", iov_len=4}, {iov_base="\r\0\0\0", iov_len=4}, {iov_base="net.usb0.dns2", iov_len=13}, {iov_base="\0\0\0\0", iov_len=4}], 4) = 25
recvfrom(3, "\0\0\0\0", 4, MSG_WAITALL, NULL, NULL) = 4
close(3)                                = 0
write(2, "dhcptool: ", 10dhcptool: )              = 10
write(2, "IP assignment is for debug purpo"..., 40IP assignment is for debug purposes ONLY) = 40
write(2, ": ", 2: )                       = 2
write(2, "Success\n", 8Success
)                = 8
mprotect(0x7729153000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x7729153000, 4096, PROT_READ) = 0
mprotect(0x7729153000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x7729153000, 4096, PROT_READ) = 0
munmap(0x7729153000, 4096)              = 0
exit_group(0)                           = ?
+++ exited with 0 +++
bullhead:/ # ping 8.8.8.8                                                                                                                                                                                   
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=114 time=131 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=114 time=58.4 ms
^C
--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 58.496/95.044/131.592/36.548 ms
bullhead:/ # 

Answer 1

看來您缺少通往 8.8.8.8 的路線（可能是默認路線）。 比較工作和非工作設置之間的路由。

Answer 2

根據上面共享的信息，似乎缺少默認路由。 您可以使用以下命令添加默認路由：

ip route add default dev usb0

添加上述路由后，我建議您使用traceroute工具或ping （如果 traceroute 不可用，則修改 TTL）從那里進一步跟蹤數據包。

Answer 3

請參閱https://elinux.org/Android_Networking#Setting_up_networking_on_bootup 。 命令

netcfg eth0 dhcp
setprop net.dns1 8.8.8.8

應該足夠了。