Return-Path: Subject: Re: [PATCH 3/4] Bluetooth: Initial support for retransmission of packets with REJ frames From: Marcel Holtmann To: "Gustavo F. Padovan" Cc: linux-bluetooth@vger.kernel.org, gustavo@padovan.org In-Reply-To: <1248675424-20977-4-git-send-email-gustavo@las.ic.unicamp.br> References: <1248675424-20977-1-git-send-email-gustavo@las.ic.unicamp.br> <1248675424-20977-2-git-send-email-gustavo@las.ic.unicamp.br> <1248675424-20977-3-git-send-email-gustavo@las.ic.unicamp.br> <1248675424-20977-4-git-send-email-gustavo@las.ic.unicamp.br> Content-Type: text/plain Date: Mon, 27 Jul 2009 12:06:47 +0200 Message-Id: <1248689207.28545.192.camel@violet> Mime-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Gustavo, > When receiving an I-frame with unexpected txSeq, receiver side start the > recovery procedure by send a REJ S-frame to the transmitter side. So the > transmitter can re-send the lost I-frame. > This patch just adds a basic support for retransmission, it doesn't > mean that ERTM now has full support to packet retransmission. > > Signed-off-by: Gustavo F. Padovan > --- > include/net/bluetooth/l2cap.h | 1 + > net/bluetooth/l2cap.c | 57 ++++++++++++++++++++++++++++++----------- > 2 files changed, 43 insertions(+), 15 deletions(-) > > diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h > index 233a2fa..653c313 100644 > --- a/include/net/bluetooth/l2cap.h > +++ b/include/net/bluetooth/l2cap.h > @@ -354,6 +354,7 @@ struct l2cap_pinfo { > #define L2CAP_CONF_MAX_CONF_RSP 2 > > #define L2CAP_CONN_SAR_SDU 0x01 > +#define L2CAP_CONN_UNDER_REJ 0x02 > > static inline int l2cap_tx_window_full(struct sock *sk) > { > diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c > index dcde60b..938d6db 100644 > --- a/net/bluetooth/l2cap.c > +++ b/net/bluetooth/l2cap.c > @@ -2903,25 +2903,37 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str > > BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len); > > - if (tx_seq != pi->expected_tx_seq) > - return -EINVAL; > + if (tx_seq == pi->expected_tx_seq) { > + if (pi->conn_state & L2CAP_CONN_UNDER_REJ) > + pi->conn_state &= !L2CAP_CONN_UNDER_REJ; This is &= ~ again. > > - err = l2cap_sar_reassembly_sdu(sk, skb, rx_control, tx_seq); > - if (unlikely(err < 0)) > - return err; > + err = l2cap_sar_reassembly_sdu(sk, skb, rx_control, tx_seq); > + if (unlikely(err < 0)) > + return err; No unlikely please. > > - L2CAP_SEQ_NUM_INC(pi->expected_tx_seq); > - L2CAP_NUM_TO_ACK_INC(pi->num_to_ack); > - if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) { > - tx_control |= L2CAP_CTRL_FRAME_TYPE; > - tx_control |= L2CAP_SUPER_RCV_READY; > - tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT; > + L2CAP_SEQ_NUM_INC(pi->expected_tx_seq); > + L2CAP_NUM_TO_ACK_INC(pi->num_to_ack); > + if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) { > + tx_control |= L2CAP_SUPER_RCV_READY; > + tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT; > + goto send; > + } > + } > + else { > + /* Unexpected txSeq. Send a REJ S-frame */ > + kfree_skb(skb); > + if (!(pi->conn_state & L2CAP_CONN_UNDER_REJ)) { > + tx_control |= L2CAP_SUPER_REJECT; > + tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT; > + pi->conn_state |= L2CAP_CONN_UNDER_REJ; > > - err = l2cap_send_sframe(pi, tx_control); > - if (unlikely(err)) > - return err; > + goto send; > + } > } > return 0; > + > +send: > + return l2cap_send_sframe(pi, tx_control); > } > > static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, struct sk_buff *skb) > @@ -2937,8 +2949,18 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str > l2cap_ertm_send(sk); > break; > > - case L2CAP_SUPER_RCV_NOT_READY: > case L2CAP_SUPER_REJECT: > + pi->expected_ack_seq = __get_reqseq(rx_control); > + l2cap_drop_acked_frames(sk); > + > + sk->sk_send_head = TX_QUEUE(sk)->next; > + pi->next_tx_seq = pi->expected_ack_seq; > + > + l2cap_ertm_send(sk); > + > + break; > + > + case L2CAP_SUPER_RCV_NOT_READY: > case L2CAP_SUPER_SELECT_REJECT: > break; > } > @@ -2985,6 +3007,11 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk > if (__is_sar_sdu_start(control)) > len -= 2; > > + /* > + * We can just drop the corrupted I-frames here. > + * Receiver will miss it and start proper recovery > + * procedures and ask retransmission. > + */ > if (L2CAP_DEFAULT_MAX_PDU_SIZE < len) > goto drop; > Regards Marcel