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rfc: print mac addr

KJ walter harms 4 participants 6 messages Dec 6, 2005 – Dec 7, 2005 Kernel janitors

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walter harms

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#0 lore raw

hi list,

must (if not all) net drivers contain something like this to print a mac addr:

for (i = 0; i < 6; i++)
printk("%2.2x%c", dev->dev_addr[i],i = 5 ? '\n' : ':');

I think it would be usefull to add a helper function.
simple question:
1. is there such a function ?
2. where to add ? each driver ? or is there a common place i do not know about ?

re,
walter

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#2 lore raw
In reply to walter harms
Quoted 4 lines · walter harms

hi list,

must (if not all) net drivers contain something like this to print a mac addr:

If that's so, then yes, a helper function is a good idea IMO.

Quoted 6 lines

for (i = 0; i < 6; i++)
printk("%2.2x%c", dev->dev_addr[i],i == 5 ? '\n' : ':');

I think it would be usefull to add a helper function. simple question:
1. is there such a function ?

If your claim that most drivers do it on their own, then I hope/guess that there is not already such a helper function...
I don't see one in include/linux/*.h.

Quoted 2 lines

2. where to add ? each driver ? or is there a common place i do not know about ?

Either
(1) inline in include/linux/{if_ether.h or etherdevice.h or netdevice.h} although I prefer one of the first two since this looks ethernet-specific (due to the "i < 6").
And change the 6 to ETH_ALEN if this is for ethernet MAC addresses. And put a space between comma and i: ",i" should be ", i".

or
(2) in net/core/dev.c.

Signature · 1 line
~Randy

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author
#3 lore raw
In reply to walter harms
Quoted 7 lines · Paolo Teti

Hi walter

Quoted 3 lines

for (i = 0; i < 6; i++)
printk("%2.2x%c", dev->dev_addr[i],i = 5 ? '\n' : ':');

1. Please post an example or the file name!

cd linux/drivers/net
grep dev_addr *.c | grep printk

Quoted 3 lines

2. Are you sure that this portion of code isn't into a DEBUG block (something like #ifdef DEBUG_xx)?

i did not check every file but looked into a few and the pattern is all the same. maybe some of them are inside a #ifdef debug the few i looked are not.

i know gregKH added a few dev helper macros but i can not find them anymore. The idea is to provide a function like:

void print_mac(struct net_device *dev)

{
    int i;
    printk(KERN_INFO);
    for (i = 0; i < MAX_ADDR_LEN; i++)
         printk("%2.2x%c", dev->dev_addr[i],i = (MAX_ADDR_LEN-1) ? '\n'

: ':');

}
may you like to return a string ?

re,
walter

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#4 lore raw
In reply to walter harms
Quoted 8 lines

(1) inline in include/linux/{if_ether.h or etherdevice.h or netdevice.h} although I prefer one of the first two since this looks ethernet-specific (due to the "i < 6").
And change the 6 to ETH_ALEN if this is for ethernet MAC addresses. And put a space between comma and i: ",i" should be ", i".

or
(2) in net/core/dev.c.

I would definitely pick the second option. There's no reason like performance for such a helper to be an inline function, so we should save .text by moving it out of line.

- R.

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#5 lore raw
In reply to walter harms
Quoted 16 lines · On Tue, 06 Dec 2005 18:11:48 +0100 walter harms wrote:
Quoted 7 lines · Paolo Teti

Hi walter

Quoted 3 lines

for (i = 0; i < 6; i++)
printk("%2.2x%c", dev->dev_addr[i],i == 5 ? '\n' : ':');

1. Please post an example or the file name!

cd linux/drivers/net
grep dev_addr *.c | grep printk

Quoted 3 lines

2. Are you sure that this portion of code isn't into a DEBUG block (something like #ifdef DEBUG_xx)?

Quoted 6 lines

i did not check every file but looked into a few and the pattern is all the same. maybe some of them are inside a #ifdef debug the few i looked are not.

i know gregKH added a few dev helper macros but i can not find them anymore. The idea is to provide a function like:

see include/linux/device.h: dev_printk() and friends.

Quoted 10 lines

void print_mac(struct net_device *dev)

{
    int i;
    printk(KERN_INFO);
    for (i = 0; i < MAX_ADDR_LEN; i++)
         printk("%2.2x%c", dev->dev_addr[i],i == (MAX_ADDR_LEN-1) ? '\n'

: ':');

}
may you like to return a string ?

I would just print it (like you did) instead of return a string (I think).

MAX_ADDR_LEN may want to be a variable in this function so that differing MAC address lengths can be supported.
And put a space between ",i".

Thanks.
---
~Randy

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