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| author | Marcel Holtmann <marcel@holtmann.org> | 2006-07-14 11:42:12 +0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-07-24 12:44:25 -0700 |
| commit | 98bcd08b5bfe78c1c9bda5768aa081e0fe4fcc4f (patch) | |
| tree | 171c7984eeaade72d57a325ee26d55e4408bbdd1 /net/bluetooth | |
| parent | 2266d8886f64c66e0a4e61e3e1c19dbc27ed00d4 (diff) | |
| download | lwn-98bcd08b5bfe78c1c9bda5768aa081e0fe4fcc4f.tar.gz lwn-98bcd08b5bfe78c1c9bda5768aa081e0fe4fcc4f.zip | |
[Bluetooth] Correct RFCOMM channel MTU for broken implementations
Some Bluetooth RFCOMM implementations try to negotiate a bigger channel
MTU than we can support for a particular session. The maximum MTU for
a RFCOMM session is limited through the L2CAP layer. So if the other
side proposes a channel MTU that is bigger than the underlying L2CAP
MTU, we should reduce it to the L2CAP MTU of the session minus five
bytes for the RFCOMM headers.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net/bluetooth')
| -rw-r--r-- | net/bluetooth/rfcomm/core.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c index 77eab8f4c7fd..332dd8f436ea 100644 --- a/net/bluetooth/rfcomm/core.c +++ b/net/bluetooth/rfcomm/core.c @@ -55,6 +55,7 @@ #define VERSION "1.8" static int disable_cfc = 0; +static int channel_mtu = -1; static unsigned int l2cap_mtu = RFCOMM_MAX_L2CAP_MTU; static struct task_struct *rfcomm_thread; @@ -812,7 +813,10 @@ static int rfcomm_send_pn(struct rfcomm_session *s, int cr, struct rfcomm_dlc *d pn->credits = 0; } - pn->mtu = htobs(d->mtu); + if (cr && channel_mtu >= 0) + pn->mtu = htobs(channel_mtu); + else + pn->mtu = htobs(d->mtu); *ptr = __fcs(buf); ptr++; @@ -1243,7 +1247,10 @@ static int rfcomm_apply_pn(struct rfcomm_dlc *d, int cr, struct rfcomm_pn *pn) d->priority = pn->priority; - d->mtu = s->mtu = btohs(pn->mtu); + d->mtu = btohs(pn->mtu); + + if (cr && d->mtu > s->mtu) + d->mtu = s->mtu; return 0; } @@ -1770,6 +1777,11 @@ static inline void rfcomm_accept_connection(struct rfcomm_session *s) s = rfcomm_session_add(nsock, BT_OPEN); if (s) { rfcomm_session_hold(s); + + /* We should adjust MTU on incoming sessions. + * L2CAP MTU minus UIH header and FCS. */ + s->mtu = min(l2cap_pi(nsock->sk)->omtu, l2cap_pi(nsock->sk)->imtu) - 5; + rfcomm_schedule(RFCOMM_SCHED_RX); } else sock_release(nsock); @@ -2087,6 +2099,9 @@ module_exit(rfcomm_exit); module_param(disable_cfc, bool, 0644); MODULE_PARM_DESC(disable_cfc, "Disable credit based flow control"); +module_param(channel_mtu, int, 0644); +MODULE_PARM_DESC(channel_mtu, "Default MTU for the RFCOMM channel"); + module_param(l2cap_mtu, uint, 0644); MODULE_PARM_DESC(l2cap_mtu, "Default MTU for the L2CAP connection"); |