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Date:      Thu, 30 Nov 2006 08:09:53 -0700 (MST)
From:      "M. Warner Losh" <imp@bsdimp.com>
To:        jhay@meraka.org.za
Cc:        freebsd-arm@FreeBSD.ORG
Subject:   Re: Gateworks 2348 and ath problem
Message-ID:  <20061130.080953.-490996389.imp@bsdimp.com>
In-Reply-To: <20061130142146.GA50022@zibbi.meraka.csir.co.za>
References:  <20061129193842.GA98569@zibbi.meraka.csir.co.za> <20061130120217.GA41346@zibbi.meraka.csir.co.za> <20061130142146.GA50022@zibbi.meraka.csir.co.za>

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In message: <20061130142146.GA50022@zibbi.meraka.csir.co.za>
            John Hay <jhay@meraka.org.za> writes:
: > 
: > Ok, I built a kernel without all those options, but it didn't make a
: > difference. I also tried sta mode and it still looks the same. Some
: > new info that I have is that when I do a tcpdump on the arm box itself,
: > adding -y IEEE802_11_RADIO makes a difference. Without it the outgoing
: > packets looks ok, but with it 2 bytes are added between the ether (802.11)
: > header and the ip(v6) header.
: 
: Ok, I found the problem. Using LLC_SNAPFRAMELEN works better than
: sizeof(struct llc). LLC_SNAPFRAMELEN is defined as 8 and sizeof()
: returns 10. Doing a grep in net/ if see that LLC_SNAPFRAMELEN is used
: a lot, so I guess this is the correct way go. I nobody has anything
: against it, I can commit it.

NetBSD marks it as __packed.  That might be a safer patch.  NetBSD
only uses LLC_SNAPFRAMELEN in token ring code.

It might be even better if we could catch these things at compile
time, but doing so may be a bit of a pita to setup (how do you know
all the relevant types to check).

Warner

: With this patch traffic seems to flow normally over the atheros wifi
: link. I have not done too much testing, but olsrd works and I can ssh
: to it.
: 
: I see a lot of rix packets:
: 
: Nov 30 15:49:29 arm-tst kernel: rix 2632 (0) bad ratekbps 0 mode 1
: Nov 30 15:49:29 arm-tst kernel: rix 2632 (0) bad ratekbps 0 mode 1
: Nov 30 15:49:30 arm-tst kernel: rix 2633 (0) bad ratekbps 0 mode 1
: Nov 30 15:49:30 arm-tst kernel: rix 2633 (0) bad ratekbps 0 mode 1
: Nov 30 15:49:30 arm-tst kernel: rix 2601 (0) bad ratekbps 0 mode 1
: 
: I don't see it on our wrap and soekris boxes, but they are running
: 6-stable... Well I have seen it, but that was if I put the link in
: 11b mode, not in 11a or 11g mode. I'm using 11a at the moment.
: 
: Sam, are they related to the rate changes you made recently? 
: 
: John
: -- 
: John Hay -- John.Hay@meraka.csir.co.za / jhay@FreeBSD.org
: 
: 
: --- net80211/ieee80211_input.c.org	Fri Nov 24 10:57:10 2006
: +++ net80211/ieee80211_input.c	Thu Nov 30 15:27:33 2006
: @@ -736,8 +736,8 @@
:  	struct ether_header *eh;
:  	struct llc *llc;
:  
: -	if (m->m_len < hdrlen + sizeof(*llc) &&
: -	    (m = m_pullup(m, hdrlen + sizeof(*llc))) == NULL) {
: +	if (m->m_len < hdrlen + LLC_SNAPFRAMELEN &&
: +	    (m = m_pullup(m, hdrlen + LLC_SNAPFRAMELEN)) == NULL) {
:  		/* XXX stat, msg */
:  		return NULL;
:  	}
: @@ -746,7 +746,7 @@
:  	if (llc->llc_dsap == LLC_SNAP_LSAP && llc->llc_ssap == LLC_SNAP_LSAP &&
:  	    llc->llc_control == LLC_UI && llc->llc_snap.org_code[0] == 0 &&
:  	    llc->llc_snap.org_code[1] == 0 && llc->llc_snap.org_code[2] == 0) {
: -		m_adj(m, hdrlen + sizeof(struct llc) - sizeof(*eh));
: +		m_adj(m, hdrlen + LLC_SNAPFRAMELEN - sizeof(*eh));
:  		llc = NULL;
:  	} else {
:  		m_adj(m, hdrlen - sizeof(*eh));
: --- net80211/ieee80211_output.c.org	Fri Nov 24 10:57:10 2006
: +++ net80211/ieee80211_output.c	Thu Nov 30 15:22:19 2006
: @@ -500,7 +500,7 @@
:  ieee80211_mbuf_adjust(struct ieee80211com *ic, int hdrsize,
:  	struct ieee80211_key *key, struct mbuf *m)
:  {
: -#define	TO_BE_RECLAIMED	(sizeof(struct ether_header) - sizeof(struct llc))
: +#define	TO_BE_RECLAIMED	(sizeof(struct ether_header) - LLC_SNAPFRAMELEN)
:  	int needed_space = hdrsize;
:  
:  	if (key != NULL) {
: @@ -527,7 +527,7 @@
:  	 * We know we are called just before stripping an Ethernet
:  	 * header and prepending an LLC header.  This means we know
:  	 * there will be
: -	 *	sizeof(struct ether_header) - sizeof(struct llc)
: +	 *	sizeof(struct ether_header) - LLC_SNAPFRAMELEN
:  	 * bytes recovered to which we need additional space for the
:  	 * 802.11 header and any crypto header.
:  	 */
: @@ -675,7 +675,7 @@
:  	}
:  
:  	/* NB: this could be optimized because of ieee80211_mbuf_adjust */
: -	m_adj(m, sizeof(struct ether_header) - sizeof(struct llc));
: +	m_adj(m, sizeof(struct ether_header) - LLC_SNAPFRAMELEN);
:  	llc = mtod(m, struct llc *);
:  	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
:  	llc->llc_control = LLC_UI;
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