Multiple definitions. Code issue

[ahuguet at cttc.es]

Greetings,

I've been adding code to the driver in order to perform certain
experiments with it. Just now, I encountered an issue that is preventing
me from advancing any further. I'm sure though that solving it should be
quite simple.

First, I attach the errors when compiling:

  LD [M]  /usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap.o
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_tx.o:(.bss+0x0):
multiple definitions of `last_data_rx'
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_rx.o:(.bss+0x0):
it was first defined here
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_ap.o:(.bss+0x0):
multiple definitions of `last_data_rx'
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_rx.o:(.bss+0x0):
it was first defined here
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_info.o:(.bss+0x0):
multiple definitions of `last_data_rx'
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_rx.o:(.bss+0x0):
it was first defined here
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_ioctl.o:(.bss+0x0):
multiple definitions of `last_data_rx'
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_rx.o:(.bss+0x0):
it was first defined here
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_main.o:(.bss+0x0):
multiple definitions of `last_data_rx'
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_rx.o:(.bss+0x0):
it was first defined here
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_proc.o:(.bss+0x0):
multiple definitions of `last_data_rx'
/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap_80211_rx.o:(.bss+0x0):
it was first defined here
make[1]: ***
[/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap/hostap.o] Error
1
make: ***
[_module_/usr/src/linux-source-2.6.17/drivers/net/wireless/hostap] Error 2


I describe now what I intended to do, and where I think the source of the
problem is.

I'd like to keep a copy of certain packets that reach the station, for
later use.
To that end, I cannot use local variables, so I tried using a global
variable.

So, at hostap_80211.h I defined the following:

struct sk_buff *last_data_rx;

The line #endif /* HOSTAP_80211_H */ goes just after my declaration.

That pointer to an sk_buff is then used in hostap_80211_rx.c (and only
there that I know of), in void hostap_80211_rx function where what I do,
mainly, is call the function skb_copy to have a copy of the current skb on
last_data_rx.
This way:
last_data_rx = skb_copy (skb,GFP_KERNEL);

that way last_data_rx should keep (or that's the idea) a copy of that skb,
even if more packets of different kind are received later, so I can have a
copy of one type of packets that have reached the station.

I thought that, since hostap_80211.h has the
#ifndef HOSTAP_80211_H
#define HOSTAP_80211_H

#endif /* HOSTAP_80211_H */

then there would be no problem with multiple declarations, but I was
clearly wrong. Perhaps I've not placed the global variable in the right
place?

Thanks for all the help, and let me know if you need more information.