Return-Path: From: ngh@isomerica.net To: linux-bluetooth@vger.kernel.org Cc: Nathan Holstein Subject: [PATCH] Reassemble segmented L2CAP PDUs upon reception Date: Wed, 29 Apr 2009 21:44:45 -0400 Message-Id: <1241055885-12250-2-git-send-email-ngh@isomerica.net> In-Reply-To: <1241055885-12250-1-git-send-email-ngh@isomerica.net> References: <1241055885-12250-1-git-send-email-ngh@isomerica.net> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: From: Nathan Holstein When configured in Enhanced Retransmission of Streaming modes, data sent over L2CAP can be broken up into multiple L2CAP SDUs. This patch adds support for reassembling these packets upon reception. --- net/bluetooth/l2cap.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 53 insertions(+), 0 deletions(-) diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index 6328fb8..7505137 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -2595,6 +2595,43 @@ static int l2cap_check_fcs(struct l2cap_pinfo *pi, struct l2cap_hdr *lh, struct return 0; } +static int l2cap_check_sar(struct l2cap_pinfo *pi, u16 control, struct sk_buff *skb) +{ + u16 mask = control & L2CAP_CONTROL_SAR_MASK; + + switch (mask) + { + case L2CAP_SAR_UNSEGMENTED: + if (pi->sdu_next != 0) + return -1; + break; + + case L2CAP_SAR_SDU_START: + if (pi->sdu_next != 0 || skb->len < 2) + return -1; + pi->sdu_next = 1; + pi->sdu_len = get_unaligned((__le16 *) skb->data); + skb_pull(skb, 2); + break; + + case L2CAP_SAR_SDU_CONTINUE: + if (pi->sdu_next >= pi->sdu_len) + return -1; + ++pi->sdu_next; + break; + + case L2CAP_SAR_SDU_END: + /* TODO: + * How do we correctly signal MSG_EOR? */ + if (pi->sdu_next != pi->sdu_len) + return -1; + pi->sdu_next = pi->sdu_len = 0; + break; + } + + return 0; +} + static inline int l2cap_data_channel_i_frame(struct sock *sk, u16 rx_control, struct sk_buff *skb) { struct l2cap_pinfo *pi = l2cap_pi(sk); @@ -2614,6 +2651,17 @@ static inline int l2cap_data_channel_i_frame(struct sock *sk, u16 rx_control, st L2CAP_SEQ_NUM_INC(pi->req_seq); tx_control = pi->req_seq << L2CAP_CONTROL_REQSEQ_SHIFT; + /* TODO: + * l2cap_check_sar() call side effects! After calling this function, + * we can't reject the SDU without possibly screwing up reassembly. + * We need to ensure the sequence number is correct, and that we can + * queue the skb before calling l2cap_check_sar(). */ + if (l2cap_check_sar(pi, rx_control, skb)) { + tx_control |= L2CAP_SUPER_REJECT; + err = -1; + goto respond; + } + if ((err = sock_queue_rcv_skb(sk, skb))) { tx_control |= L2CAP_SUPER_RCV_NOT_READY; goto respond; @@ -2694,6 +2742,11 @@ static int l2cap_data_channel_streaming(struct sock *sk, struct l2cap_hdr *lh, s control = get_unaligned((__le16 *) skb->data); skb_pull(skb, 2); + /* Todo: + * is this the proper behavior? */ + if (l2cap_is_I_frame(control) && l2cap_check_sar(pi, control, skb)) + return -1; + if (!sock_queue_rcv_skb(sk, skb)) return -1; -- 1.6.0.6