[U-Boot] [PATCH 5/5] net: sandbox-raw: Allow interface to be specified by index
Joe Hershberger
joe.hershberger at ni.com
Wed Jun 27 04:58:53 UTC 2018
Hi Heinrich,
On Tue, Jun 26, 2018 at 8:15 PM, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> On 06/26/2018 11:19 PM, Joe Hershberger wrote:
>> With systemd stable interface names, eth0 will almost never exist.
>> Instead of using that name in the sandbox.dts, use index 2 (the first
>> interface after "lo"). Enumerate the interfaces on the system to choose
>> a valid interace name.
>>
>> Signed-off-by: Joe Hershberger <joe.hershberger at ni.com>
>
> Hello Joe,
>
> thanks for addressing this issue.
>
> On my laptop the raw interfaces are currently called:
> 1 - lo - loopback
> 2 - enp0s25 - wired ethernet
> 3 - wlp12s0 - WLAN
>
> But this list is not static:
>
> It is allowable to define multiple loopback interfaces. Additional
> bridges, tap and tun interfaces may be defined. A computer may also have
> multiple wired and wireless interfaces. And of cause I may choose to
> plug in an additional ethernet adapter while my computer is running.
>
> The interface index does not tell which interface is actually connected
> to the network. My laptop uses wpl12s0 (index = 3) for sending out this
> mail. So, please, do not replace one invalid assumption (eth0) by
> another (index = 2).
While index=2 is not an ideal assumption, I don't think invalid is a
fair description. It is far better than eth0, which on modern systems
is very unlikely. The driver is probed based on DTS entries. This is
simply for manual testing, so if the common situation doesn't apply to
a person, they can easily modify the DTS to specify the name of their
interface, or they can specify a different index. I don't think the
fact that it doesn't ideally fit every possible situation warrants
changing how these are probed to somehow be dynamically created based
on the OS.
> I doubt there is a guarantee that index 1 is a loopback interface on
> POSIX systems. If you need a special treatment of loopback devices you
> could analyze the properties of each interface to detect which one is a
> loopback interface.
The only special treatment for local interfaces is that they don't
work with raw sockets. You can see that in the code. At the same time,
the local interface is pretty crippled for testing the network stack
anyway (no ICMP support) so if there is more than one (why would you?)
then that one not named "lo" will not work.
> There is no need for using the device tree for the specification of
> interfaces. Instead a raw ethernet device can be set up for each
> interface. Let the user choose at runtime which device he wants to use
> for testing.
You say there is no need, but that's the way it works in the sandbox.
There is no "OS" subsystem that is there to enumerate new interfaces
dynamically, the way something like PCI on a real board would. I
don't think we would want it completely automatic anyway, because
things like the test.dts have only fake sandbox eth interfaces, not
any raw, since we want the unit test to run consistently regardless of
the arrangement of network interfaces on the test system it runs on.
Cheers,
-Joe
> Best regards
>
> Heinrich
>
>> ---
>>
>> arch/sandbox/cpu/eth-raw-os.c | 28 ++++++++++++++++++++++++++++
>> arch/sandbox/dts/sandbox.dts | 2 +-
>> arch/sandbox/include/asm/eth-raw-os.h | 4 +++-
>> drivers/net/sandbox-raw.c | 8 +++++++-
>> 4 files changed, 39 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/sandbox/cpu/eth-raw-os.c b/arch/sandbox/cpu/eth-raw-os.c
>> index 61f23ed210..11b5271f31 100644
>> --- a/arch/sandbox/cpu/eth-raw-os.c
>> +++ b/arch/sandbox/cpu/eth-raw-os.c
>> @@ -150,6 +150,34 @@ int sandbox_eth_raw_os_start(const char *ifname, unsigned char *ethmac,
>> return _raw_packet_start(ifname, ethmac, priv);
>> }
>>
>> +int sandbox_eth_raw_os_start_idx(unsigned int ifindex, unsigned char *ethmac,
>> + struct eth_sandbox_raw_priv *priv)
>> +{
>> + int ret;
>> + struct if_nameindex *ni, *i;
>> + const char *ifname = NULL;
>> +
>> + ni = if_nameindex();
>> + if (!ni)
>> + return -EINVAL;
>> +
>> + for (i = ni; !(i->if_index == 0 && !i->if_name); i++) {
>> + if (ifindex == i->if_index) {
>> + ifname = i->if_name;
>> + printf("(%s)\n", ifname);
>> + break;
>> + }
>> + }
>> + /* Don't bother supporting 'lo' by index. Just use the name in DTS */
>> + if (ifname)
>> + ret = _raw_packet_start(ifname, ethmac, priv);
>> + else
>> + ret = -EINVAL;
>> +
>> + if_freenameindex(ni);
>> + return ret;
>> +}
>> +
>> int sandbox_eth_raw_os_send(void *packet, int length,
>> struct eth_sandbox_raw_priv *priv)
>> {
>> diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts
>> index 0ea2452742..e7f6c194d0 100644
>> --- a/arch/sandbox/dts/sandbox.dts
>> +++ b/arch/sandbox/dts/sandbox.dts
>> @@ -56,7 +56,7 @@
>> eth at 80000000 {
>> compatible = "sandbox,eth-raw";
>> reg = <0x80000000 0x1000>;
>> - host-raw-interface = "eth0";
>> + host-raw-interface-idx = <2>;
>> };
>>
>> eth at 90000000 {
>> diff --git a/arch/sandbox/include/asm/eth-raw-os.h b/arch/sandbox/include/asm/eth-raw-os.h
>> index f986d3142d..70b29b4508 100644
>> --- a/arch/sandbox/include/asm/eth-raw-os.h
>> +++ b/arch/sandbox/include/asm/eth-raw-os.h
>> @@ -29,7 +29,9 @@ struct eth_sandbox_raw_priv {
>> };
>>
>> int sandbox_eth_raw_os_start(const char *ifname, unsigned char *ethmac,
>> - struct eth_sandbox_raw_priv *priv);
>> + struct eth_sandbox_raw_priv *priv);
>> +int sandbox_eth_raw_os_start_idx(unsigned int ifindex, unsigned char *ethmac,
>> + struct eth_sandbox_raw_priv *priv);
>> int sandbox_eth_raw_os_send(void *packet, int length,
>> struct eth_sandbox_raw_priv *priv);
>> int sandbox_eth_raw_os_recv(void *packet, int *length,
>> diff --git a/drivers/net/sandbox-raw.c b/drivers/net/sandbox-raw.c
>> index f835a6a7f3..3bde8d84ce 100644
>> --- a/drivers/net/sandbox-raw.c
>> +++ b/drivers/net/sandbox-raw.c
>> @@ -22,6 +22,7 @@ static int sb_eth_raw_start(struct udevice *dev)
>> struct eth_sandbox_raw_priv *priv = dev_get_priv(dev);
>> struct eth_pdata *pdata = dev_get_platdata(dev);
>> const char *interface;
>> + u32 index;
>>
>> debug("eth_sandbox_raw: Start\n");
>>
>> @@ -37,7 +38,12 @@ static int sb_eth_raw_start(struct udevice *dev)
>> priv);
>> }
>>
>> - return -EINVAL;
>> + if (dev_read_u32(dev, "host-raw-interface-idx", &index) < 0)
>> + return -EINVAL;
>> +
>> + printf("eth_sandbox_raw: Using interface index %d from DT ", index);
>> +
>> + return sandbox_eth_raw_os_start_idx(index, pdata->enetaddr, priv);
>> }
>>
>> static int sb_eth_raw_send(struct udevice *dev, void *packet, int length)
>>
>
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot
More information about the U-Boot
mailing list