freebsd-skq/sys/net80211/ieee80211_input.h
adrian 198275796f Fix some corner cases in the net80211 sequence number retransmission
handling.

The current sequence number code does a few things incorrectly:

* It didn't try eliminating duplications from HT nodes. I guess it's assumed
  that out of order / retransmission handling would be handled by the AMPDU RX
  routines. If a HT node isn't doing AMPDU RX, then retransmissions need to
  be eliminated. Since most of my debugging is based on this (as AMPDU TX
  software packet aggregation isn't yet handled), handle this corner case.

* When a sequence number of 4095 was received, any subsequent sequence number
  is going to be (by definition) less than 4095. So if the following sequence
  number (0) doesn't initially occur and the retransmit is received, it's
  incorrectly eliminated by the IEEE80211_FC1_RETRY && SEQ_LEQ() check.
  Try to handle this better.

This almost completely eliminates out of order TCP statistics showing up during
iperf testing for the 11a, 11g and non-aggregate 11n AMPDU RX case. The only
other packet loss conditions leading to this are due to baseband resets or
heavy interference.
2011-05-04 02:23:59 +00:00

259 lines
8.5 KiB
C

/*-
* Copyright (c) 2007-2009 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NET80211_IEEE80211_INPUT_H_
#define _NET80211_IEEE80211_INPUT_H_
/* Verify the existence and length of __elem or get out. */
#define IEEE80211_VERIFY_ELEMENT(__elem, __maxlen, _action) do { \
if ((__elem) == NULL) { \
IEEE80211_DISCARD(vap, IEEE80211_MSG_ELEMID, \
wh, NULL, "%s", "no " #__elem ); \
vap->iv_stats.is_rx_elem_missing++; \
_action; \
} else if ((__elem)[1] > (__maxlen)) { \
IEEE80211_DISCARD(vap, IEEE80211_MSG_ELEMID, \
wh, NULL, "bad " #__elem " len %d", (__elem)[1]); \
vap->iv_stats.is_rx_elem_toobig++; \
_action; \
} \
} while (0)
#define IEEE80211_VERIFY_LENGTH(_len, _minlen, _action) do { \
if ((_len) < (_minlen)) { \
IEEE80211_DISCARD(vap, IEEE80211_MSG_ELEMID, \
wh, NULL, "ie too short, got %d, expected %d", \
(_len), (_minlen)); \
vap->iv_stats.is_rx_elem_toosmall++; \
_action; \
} \
} while (0)
#ifdef IEEE80211_DEBUG
void ieee80211_ssid_mismatch(struct ieee80211vap *, const char *tag,
uint8_t mac[IEEE80211_ADDR_LEN], uint8_t *ssid);
#define IEEE80211_VERIFY_SSID(_ni, _ssid, _action) do { \
if ((_ssid)[1] != 0 && \
((_ssid)[1] != (_ni)->ni_esslen || \
memcmp((_ssid) + 2, (_ni)->ni_essid, (_ssid)[1]) != 0)) { \
if (ieee80211_msg_input(vap)) \
ieee80211_ssid_mismatch(vap, \
ieee80211_mgt_subtype_name[subtype >> \
IEEE80211_FC0_SUBTYPE_SHIFT], \
wh->i_addr2, _ssid); \
vap->iv_stats.is_rx_ssidmismatch++; \
_action; \
} \
} while (0)
#else /* !IEEE80211_DEBUG */
#define IEEE80211_VERIFY_SSID(_ni, _ssid, _action) do { \
if ((_ssid)[1] != 0 && \
((_ssid)[1] != (_ni)->ni_esslen || \
memcmp((_ssid) + 2, (_ni)->ni_essid, (_ssid)[1]) != 0)) { \
vap->iv_stats.is_rx_ssidmismatch++; \
_action; \
} \
} while (0)
#endif /* !IEEE80211_DEBUG */
/* unalligned little endian access */
#define LE_READ_2(p) \
((uint16_t) \
((((const uint8_t *)(p))[0] ) | \
(((const uint8_t *)(p))[1] << 8)))
#define LE_READ_4(p) \
((uint32_t) \
((((const uint8_t *)(p))[0] ) | \
(((const uint8_t *)(p))[1] << 8) | \
(((const uint8_t *)(p))[2] << 16) | \
(((const uint8_t *)(p))[3] << 24)))
static __inline int
iswpaoui(const uint8_t *frm)
{
return frm[1] > 3 && LE_READ_4(frm+2) == ((WPA_OUI_TYPE<<24)|WPA_OUI);
}
static __inline int
iswmeoui(const uint8_t *frm)
{
return frm[1] > 3 && LE_READ_4(frm+2) == ((WME_OUI_TYPE<<24)|WME_OUI);
}
static __inline int
iswmeparam(const uint8_t *frm)
{
return frm[1] > 5 && LE_READ_4(frm+2) == ((WME_OUI_TYPE<<24)|WME_OUI) &&
frm[6] == WME_PARAM_OUI_SUBTYPE;
}
static __inline int
iswmeinfo(const uint8_t *frm)
{
return frm[1] > 5 && LE_READ_4(frm+2) == ((WME_OUI_TYPE<<24)|WME_OUI) &&
frm[6] == WME_INFO_OUI_SUBTYPE;
}
static __inline int
isatherosoui(const uint8_t *frm)
{
return frm[1] > 3 && LE_READ_4(frm+2) == ((ATH_OUI_TYPE<<24)|ATH_OUI);
}
static __inline int
istdmaoui(const uint8_t *frm)
{
return frm[1] > 3 && LE_READ_4(frm+2) == ((TDMA_OUI_TYPE<<24)|TDMA_OUI);
}
static __inline int
ishtcapoui(const uint8_t *frm)
{
return frm[1] > 3 && LE_READ_4(frm+2) == ((BCM_OUI_HTCAP<<24)|BCM_OUI);
}
static __inline int
ishtinfooui(const uint8_t *frm)
{
return frm[1] > 3 && LE_READ_4(frm+2) == ((BCM_OUI_HTINFO<<24)|BCM_OUI);
}
#include <sys/endian.h> /* For le16toh() */
/*
* Check the current frame sequence number against the current TID
* state and return whether it's in sequence or should be dropped.
*
* Since out of order packet and duplicate packet eliminations should
* be done by the AMPDU RX code, this routine blindly accepts all
* frames from a HT station w/ a TID that is currently doing AMPDU-RX.
* HT stations without WME or where the TID is not doing AMPDU-RX
* are checked like non-HT stations.
*
* The routine only eliminates packets whose sequence/fragment
* match or are less than the last seen sequence/fragment number
* AND are retransmits It doesn't try to eliminate out of order packets.
*
* Since all frames after sequence number 4095 will be less than 4095
* (as the seqnum wraps), handle that special case so packets aren't
* incorrectly dropped - ie, if the next packet is sequence number 0
* but a retransmit since the initial packet didn't make it.
*/
static __inline int
ieee80211_check_rxseq(struct ieee80211_node *ni, struct ieee80211_frame *wh)
{
#define SEQ_LEQ(a,b) ((int)((a)-(b)) <= 0)
#define SEQ_EQ(a,b) ((int)((a)-(b)) == 0)
#define HAS_SEQ(type) ((type & 0x4) == 0)
#define SEQNO(a) ((a) >> IEEE80211_SEQ_SEQ_SHIFT)
#define FRAGNO(a) ((a) & IEEE80211_SEQ_FRAG_MASK)
uint16_t rxseq;
uint8_t type;
uint8_t tid;
struct ieee80211_rx_ampdu *rap;
rxseq = le16toh(*(uint16_t *)wh->i_seq);
type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
/* Types with no sequence number are always treated valid */
if (! HAS_SEQ(type))
return 1;
tid = ieee80211_gettid(wh);
/*
* Only do the HT AMPDU check for WME stations; non-WME HT stations
* shouldn't exist outside of debugging. We should at least
* handle that.
*/
if (tid < WME_NUM_TID) {
rap = &ni->ni_rx_ampdu[tid];
/* HT nodes currently doing RX AMPDU are always valid */
if ((ni->ni_flags & IEEE80211_NODE_HT) &&
(rap->rxa_flags & IEEE80211_AGGR_RUNNING))
return 1;
}
/*
* Otherwise, retries for packets below or equal to the last
* seen sequence number should be dropped.
*/
/*
* Treat frame seqnum 4095 as special due to boundary
* wrapping conditions.
*/
if (SEQNO(ni->ni_rxseqs[tid]) == 4095) {
/*
* Drop retransmits on seqnum 4095/current fragment for itself.
*/
if (SEQ_EQ(rxseq, ni->ni_rxseqs[tid]) &&
(wh->i_fc[1] & IEEE80211_FC1_RETRY))
return 0;
/*
* Treat any subsequent frame as fine if the last seen frame
* is 4095 and it's not a retransmit for the same sequence
* number. However, this doesn't capture incorrectly ordered
* fragments w/ sequence number 4095. It shouldn't be seen
* in practice, but see the comment above for further info.
*/
return 1;
}
/*
* At this point we assume that retransmitted seq/frag numbers below
* the current can simply be eliminated.
*/
if ((wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
SEQ_LEQ(rxseq, ni->ni_rxseqs[tid]))
return 0;
return 1;
#undef SEQ_LEQ
#undef SEQ_EQ
#undef HAS_SEQ
#undef SEQNO
#undef FRAGNO
}
void ieee80211_deliver_data(struct ieee80211vap *,
struct ieee80211_node *, struct mbuf *);
struct mbuf *ieee80211_defrag(struct ieee80211_node *,
struct mbuf *, int);
struct mbuf *ieee80211_realign(struct ieee80211vap *, struct mbuf *, size_t);
struct mbuf *ieee80211_decap(struct ieee80211vap *, struct mbuf *, int);
struct mbuf *ieee80211_decap1(struct mbuf *, int *);
int ieee80211_setup_rates(struct ieee80211_node *ni,
const uint8_t *rates, const uint8_t *xrates, int flags);
void ieee80211_send_error(struct ieee80211_node *,
const uint8_t mac[IEEE80211_ADDR_LEN], int subtype, int arg);
int ieee80211_alloc_challenge(struct ieee80211_node *);
int ieee80211_parse_beacon(struct ieee80211_node *, struct mbuf *,
struct ieee80211_scanparams *);
int ieee80211_parse_action(struct ieee80211_node *, struct mbuf *);
#endif /* _NET80211_IEEE80211_INPUT_H_ */