Fixes on arp output and parameters validation

[garga]

Summary

• 'blackhole' and 'reject' are mutually exclusive, replace printf() by errx() when both are selected.
• 'trail' option is no longer supported since first import of arp from BSD 4.4. XXX message was added 13 years ago in r128192. I believe it's time to remove it.
• Use warnx() to print some informative messages instead of printf()
• Replace strncmp() by strcmp() when validating parameters and exit when invalid parameter is found

Sponsored by: Rubicon Communications (Netgate)
MFC after: 1 week

[vangyzen]

usr.sbin/arp/arp.c

322

By using strncmp, this code accepts parameters like "temperature", "template", and "tempestuous", and treats them like "temp". Likewise for the other cases below. This seems wrong. You didn't break it, obviously, but while you're here...

344

I wonder if blackhole and reject still work after the L2/L3 separation in FreeBSD 8.0. (I think it was 8.0.) Since you're apparently in a cleanup mood... :-)

365

warnx appends a newline.

401

warnx appends a newline.

872–873

warnx appends a newline.

However, this seems like an informative message on the successful path, not a warning, so I think printf is more appropriate.

In any case, combining the two printf calls into one makes sense.

[garga]

• Removed \n from warnx() calls
• Back success informative message to printf, but kept a single call
• Replace strncmp() by strcmp() on parameters check and exit if wrong parameter is used

[garga]

usr.sbin/arp/arp.c

322

Replaced by strcmp() and added else condition to exit for unknown parameters

344

I can check it after and submit a new review. Sounds good?

365

Fixed

401

Fixed

872–873

You are right, back to printf(), but a single one

[vangyzen]

usr.sbin/arp/arp.c

344

Sure. It's a logically separate change, so it should be a separate commit.

489

Here's another extra newline that I missed the first time.

[garga]

Remove \n from warnx message

[garga]

usr.sbin/arp/arp.c

489

fixed as well, thanks!

[allanjude]

Approved for commit