Date: Sat, 27 Sep 2008 12:16:00 -0700 From: Sam Leffler <sam@freebsd.org> To: John Hay <jhay@meraka.org.za> Cc: freebsd-mobile@freebsd.org Subject: Re: setting bssid in adhoc mode Message-ID: <48DE8670.60606@freebsd.org> In-Reply-To: <20080927071046.GA94774@zibbi.meraka.csir.co.za> References: <20080922132500.GA25677@zibbi.meraka.csir.co.za> <3a142e750809250741j7b9003e4q539618d1c9407def@mail.gmail.com> <20080925161338.GA69284@zibbi.meraka.csir.co.za> <3a142e750809251159p3f5f3bam11243b3f144859c2@mail.gmail.com> <20080926055522.GA13842@zibbi.meraka.csir.co.za> <48DD210E.6050300@freebsd.org> <20080927071046.GA94774@zibbi.meraka.csir.co.za>
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John Hay wrote:
>>>>>>> I'm trying out the new ath/wlan stuff in current. Should one still be
>>>>>>> able to set the bssid in adhoc mode? We normally lock the bssid in
>>>>>>> an adhoc network because of problems that the network split and does
>>>>>>> not merge, if you do not do it.
>>>>>>>
>>>>>>> What I have done is this:
>>>>>>>
>>>>>>> # ifconfig wlan0 create wlandev ath0 wlanmode adhoc
>>>>>>> # ifconfig wlan0 ssid ptamesh up
>>>>>>>
>>>>>>> Up to here works well. It will scan and if it finds another node with
>>>>>>> the
>>>>>>> same ssid, it will "lock" on that channel and use the correct bssid.
>>>>>>>
>>>>>>> If it does not find another node with the same ssid, it will start it
>>>>>>> own thing on channel 10. But it looks like one cannot set the bssid.
>>>>>>>
>>>>>>> # ifconfig wlan0 bssid 02:07:ca:fe:ba:be
>>>>>>> ifconfig: 02:07:ca:fe:ba:be: bad value
>>>>>>>
>>>>>>>
>>>>>> I had similar experience with STA mode, instead I use ap (ap is alias
>>>>>> for bssid, at least it works in STA mode)
>>>>>> I never bothered is this bug in manual page, ifconfig or in something
>>>>>> else
>>>>>> ...
>>>>>>
>>>>>>
>>>>> Ah, thanks yes, "ifconfig wlan0 ap 02:07:ca:fe:ba:be" works just fine.
>>>>> Just do not try to unset it with "ifconfig wlan0 ap -". That is an
>>>>> alias for "panic now" :-)
>>>>>
>>>>>
>>>> Well, on my system it doesnt panic here.
>>>> So more info to debug "your" panic is required ...
>>>>
>>>>
>>> I'll have to see if I can reproduce it.
>>>
>>>
>>>
>>>>> So it looks like ifconfig is getting confused with the many different
>>>>> uses of the keyword bssid.
>>>>>
>>>>> I must say I still do not understand what the other use for bssid is.
>>>>> Close to the end of ifconfig/ifieee80211.c there are these:
>>>>>
>>>>> DEF_CMD_ARG("bssid", set80211bssid),
>>>>> DEF_CMD_ARG("ap", set80211bssid),
>>>>> ...
>>>>> DEF_CLONE_CMD("bssid", 1, set80211clone_bssid),
>>>>> DEF_CLONE_CMD("-bssid", 0, set80211clone_bssid),
>>>>>
>>>>> So my guess is that I was hitting the clone version when in fact I
>>>>> needed the other version. Luckily ap does not have a clone version.
>>>>> So when should the clone version be used? And how does ifconfig
>>>>> decide which one to use?
>>>>>
>>>>>
>>> I looked into the ifconfig code a bit more. I think that with the
>>> current code in the ifconfig() and cmd_lookup() functions, it is
>>> imposssible to have two different keywords that share the same
>>> keyword. cmd_lookup() will always search until it finds the first
>>> instance in the list and return that. The first instance in this
>>> case being the last one added.
>>>
>>>
>> Correct.
>>
>>
>>> So either the code must change or one of the bssid keywords have
>>> to change. My suggestion would be to keep the bssid for which ap
>>> is an alias and change the other one. Anybody have a suggestion
>>> of what to change it to?
>>>
>>>
>>>
>> I prefer to change the code to handle this ambiguity within
>> ifieee80211.c. You cannot use both together or at least they are
>> redundant. I'll look at it when I've got time; but don't let me
>> distract you.
>>
>
> So what should the behaviour be? How should ifconfig know which bssid
> function to use? Should the clone variant be used when it is used on
> the same line as create? And the other if there is not a create on the
> line? Or some other way? And should the other DEF_CLONE... keywords
> also be handled the same way?
>
> John
>
Try the attached change. It looked easier to fix this for all possible
usage instead of complicating the 802.11 stuff. The change forces all
keywords marked "DEF_CLONE" to come first on the command line followed
by keywords that are marked !DEF_CLONE. At some point it's likely we'll
need to stick a real parser in ifconfig but I think this change is small
enough to just do it this way (it also slightly cleans up the hack for
pushing the clone operation out before parsing/handling subsequent cmd
line args).
Sam
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Content-Type: text/plain;
name="ifconfig.patch"
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Content-Disposition: inline;
filename="ifconfig.patch"
Index: ifconfig.c
===================================================================
--- ifconfig.c (revision 183416)
+++ ifconfig.c (working copy)
@@ -392,14 +392,21 @@
}
static const struct cmd *
-cmd_lookup(const char *name)
+cmd_lookup(const char *name, int iscreate)
{
#define N(a) (sizeof(a)/sizeof(a[0]))
const struct cmd *p;
for (p = cmds; p != NULL; p = p->c_next)
- if (strcmp(name, p->c_name) == 0)
- return p;
+ if (strcmp(name, p->c_name) == 0) {
+ if (iscreate) {
+ if (p->c_iscloneop)
+ return p;
+ } else {
+ if (!p->c_iscloneop)
+ return p;
+ }
+ }
return NULL;
#undef N
}
@@ -437,6 +444,7 @@
ifconfig(int argc, char *const *argv, int iscreate, const struct afswtch *afp)
{
const struct afswtch *nafp;
+ const struct cmd *p;
struct callback *cb;
int s;
@@ -452,9 +460,38 @@
err(1, "socket(family %u,SOCK_DGRAM", ifr.ifr_addr.sa_family);
while (argc > 0) {
- const struct cmd *p;
-
- p = cmd_lookup(*argv);
+ p = cmd_lookup(*argv, iscreate);
+ if (iscreate && p == NULL) {
+ /*
+ * Push the clone create callback so the new
+ * device is created and can be used for any
+ * remaining arguments.
+ */
+ cb = callbacks;
+ if (cb == NULL)
+ errx(1, "internal error, no callback");
+ callbacks = cb->cb_next;
+ cb->cb_func(s, cb->cb_arg);
+ iscreate = 0;
+ /*
+ * Handle any address family spec that
+ * immediately follows and potentially
+ * recreate the socket.
+ */
+ nafp = af_getbyname(*argv);
+ if (nafp != NULL) {
+ argc--, argv++;
+ if (nafp != afp) {
+ close(s);
+ afp = nafp;
+ goto top;
+ }
+ }
+ /*
+ * Look for a normal parameter.
+ */
+ continue;
+ }
if (p == NULL) {
/*
* Not a recognized command, choose between setting
@@ -463,33 +500,6 @@
p = (setaddr ? &setifdstaddr_cmd : &setifaddr_cmd);
}
if (p->c_u.c_func || p->c_u.c_func2) {
- if (iscreate && !p->c_iscloneop) {
- /*
- * Push the clone create callback so the new
- * device is created and can be used for any
- * remaining arguments.
- */
- cb = callbacks;
- if (cb == NULL)
- errx(1, "internal error, no callback");
- callbacks = cb->cb_next;
- cb->cb_func(s, cb->cb_arg);
- iscreate = 0;
- /*
- * Handle any address family spec that
- * immediately follows and potentially
- * recreate the socket.
- */
- nafp = af_getbyname(*argv);
- if (nafp != NULL) {
- argc--, argv++;
- if (nafp != afp) {
- close(s);
- afp = nafp;
- goto top;
- }
- }
- }
if (p->c_parameter == NEXTARG) {
if (argv[1] == NULL)
errx(1, "'%s' requires argument",
--------------020202030001020600070906--
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