Return-Path: From: "Gustavo F. Padovan" To: linux-bluetooth@vger.kernel.org Cc: marcel@holtmann.org, gustavo@padovan.org Subject: [PATCH 6/8] Bluetooth: Add support to FCS Option on L2CAP Date: Mon, 17 Aug 2009 23:53:48 -0300 Message-Id: <1250564030-13684-6-git-send-email-gustavo@las.ic.unicamp.br> In-Reply-To: <1250564030-13684-5-git-send-email-gustavo@las.ic.unicamp.br> References: <1250564030-13684-1-git-send-email-gustavo@las.ic.unicamp.br> <1250564030-13684-2-git-send-email-gustavo@las.ic.unicamp.br> <1250564030-13684-3-git-send-email-gustavo@las.ic.unicamp.br> <1250564030-13684-4-git-send-email-gustavo@las.ic.unicamp.br> <1250564030-13684-5-git-send-email-gustavo@las.ic.unicamp.br> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Implement CRC16 check for L2CAP packets. FCS is used by Streaming Mode and Enhanced Retransmission Mode and is a extra check for the packet content. CRC16 is the default, L2CAP won't use FCS only when both side send a "No FCS" request. Initially based on a patch from Nathan Holstein Signed-off-by: Gustavo F. Padovan --- include/net/bluetooth/l2cap.h | 2 + net/bluetooth/l2cap.c | 101 ++++++++++++++++++++++++++++++++++++++--- 2 files changed, 97 insertions(+), 6 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 33aea42..abb1b56 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -54,6 +54,7 @@ struct l2cap_options { __u16 imtu; __u16 flush_to; __u8 mode; + __u8 fcs; }; #define L2CAP_CONNINFO 0x02 @@ -348,6 +349,7 @@ struct l2cap_pinfo { #define L2CAP_CONF_MTU_DONE 0x08 #define L2CAP_CONF_MODE_DONE 0x10 #define L2CAP_CONF_CONNECT_PEND 0x20 +#define L2CAP_CONF_NO_FCS_RECV 0x40 #define L2CAP_CONF_STATE2_DEVICE 0x80 #define L2CAP_CONF_MAX_CONF_REQ 2 diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index d4bf045..353422b 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -338,11 +339,14 @@ static inline int l2cap_send_sframe(struct l2cap_pinfo *pi, u16 control) struct sk_buff *skb; struct l2cap_hdr *lh; struct l2cap_conn *conn = pi->conn; - int count; + int count, hlen = L2CAP_HDR_SIZE + 2; + + if (pi->fcs == L2CAP_FCS_CRC16) + hlen += 2; BT_DBG("pi %p, control 0x%2.2x", pi, control); - count = min_t(unsigned int, conn->mtu, L2CAP_HDR_SIZE + 2); + count = min_t(unsigned int, conn->mtu, hlen); control |= L2CAP_CTRL_FRAME_TYPE; skb = bt_skb_alloc(count, GFP_ATOMIC); @@ -350,10 +354,15 @@ static inline int l2cap_send_sframe(struct l2cap_pinfo *pi, u16 control) return -ENOMEM; lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE); - lh->len = cpu_to_le16(2); + lh->len = cpu_to_le16(hlen - L2CAP_HDR_SIZE); lh->cid = cpu_to_le16(pi->dcid); put_unaligned_le16(control, skb_put(skb, 2)); + if (pi->fcs == L2CAP_FCS_CRC16) { + u16 fcs = crc16(0, (u8 *)lh, count - 2); + put_unaligned_le16(fcs, skb_put(skb, 2)); + } + return hci_send_acl(pi->conn->hcon, skb, 0); } @@ -1247,7 +1256,7 @@ static int l2cap_streaming_send(struct sock *sk) { struct sk_buff *skb, *tx_skb; struct l2cap_pinfo *pi = l2cap_pi(sk); - u16 control; + u16 control, fcs; int err; while ((skb = sk->sk_send_head)) { @@ -1257,6 +1266,11 @@ static int l2cap_streaming_send(struct sock *sk) control |= pi->next_tx_seq << L2CAP_CTRL_TXSEQ_SHIFT; put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE); + if (l2cap_pi(sk)->fcs == L2CAP_FCS_CRC16) { + fcs = crc16(0, (u8 *)tx_skb->data, tx_skb->len - 2); + put_unaligned_le16(fcs, tx_skb->data + tx_skb->len - 2); + } + err = l2cap_do_send(sk, tx_skb); if (err < 0) { l2cap_send_disconn_req(pi->conn, sk); @@ -1280,7 +1294,7 @@ static int l2cap_ertm_send(struct sock *sk) { struct sk_buff *skb, *tx_skb; struct l2cap_pinfo *pi = l2cap_pi(sk); - u16 control; + u16 control, fcs; int err; if (pi->conn_state & L2CAP_CONN_WAIT_ACK) @@ -1303,6 +1317,11 @@ static int l2cap_ertm_send(struct sock *sk) put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE); + if (l2cap_pi(sk)->fcs == L2CAP_FCS_CRC16) { + fcs = crc16(0, (u8 *)skb->data, tx_skb->len - 2); + put_unaligned_le16(fcs, skb->data + tx_skb->len - 2); + } + err = l2cap_do_send(sk, tx_skb); if (err < 0) { l2cap_send_disconn_req(pi->conn, sk); @@ -1426,6 +1445,9 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct sock *sk, struct msghdr *m if (sdulen) hlen += 2; + if (l2cap_pi(sk)->fcs == L2CAP_FCS_CRC16) + hlen += 2; + count = min_t(unsigned int, (conn->mtu - hlen), len); skb = bt_skb_send_alloc(sk, count + hlen, msg->msg_flags & MSG_DONTWAIT, &err); @@ -1446,6 +1468,9 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct sock *sk, struct msghdr *m return ERR_PTR(err); } + if (l2cap_pi(sk)->fcs == L2CAP_FCS_CRC16) + put_unaligned_le16(0, skb_put(skb, 2)); + bt_cb(skb)->retries = 0; return skb; } @@ -1631,6 +1656,7 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __us opts.omtu = l2cap_pi(sk)->omtu; opts.flush_to = l2cap_pi(sk)->flush_to; opts.mode = l2cap_pi(sk)->mode; + opts.fcs = l2cap_pi(sk)->fcs; len = min_t(unsigned int, sizeof(opts), optlen); if (copy_from_user((char *) &opts, optval, len)) { @@ -1641,6 +1667,7 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __us l2cap_pi(sk)->imtu = opts.imtu; l2cap_pi(sk)->omtu = opts.omtu; l2cap_pi(sk)->mode = opts.mode; + l2cap_pi(sk)->fcs = opts.fcs; break; case L2CAP_LM: @@ -1754,6 +1781,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __us opts.omtu = l2cap_pi(sk)->omtu; opts.flush_to = l2cap_pi(sk)->flush_to; opts.mode = l2cap_pi(sk)->mode; + opts.fcs = l2cap_pi(sk)->fcs; len = min_t(unsigned int, len, sizeof(opts)); if (copy_to_user(optval, (char *) &opts, len)) @@ -2152,6 +2180,15 @@ done: l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc), (unsigned long) &rfc); + + if (!(pi->conn->feat_mask & L2CAP_FEAT_FCS)) + break; + + if (pi->fcs == L2CAP_FCS_NONE || + pi->conf_state & L2CAP_CONF_NO_FCS_RECV) { + pi->fcs = L2CAP_FCS_NONE; + l2cap_add_conf_opt(&ptr, L2CAP_CONF_FCS, 1, pi->fcs); + } break; case L2CAP_MODE_STREAMING: @@ -2164,6 +2201,15 @@ done: l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc), (unsigned long) &rfc); + + if (!(pi->conn->feat_mask & L2CAP_FEAT_FCS)) + break; + + if (pi->fcs == L2CAP_FCS_NONE || + pi->conf_state & L2CAP_CONF_NO_FCS_RECV) { + pi->fcs = L2CAP_FCS_NONE; + l2cap_add_conf_opt(&ptr, L2CAP_CONF_FCS, 1, pi->fcs); + } break; } @@ -2215,6 +2261,12 @@ static int l2cap_parse_conf_req(struct sock *sk, void *data) memcpy(&rfc, (void *) val, olen); break; + case L2CAP_CONF_FCS: + if (val == L2CAP_FCS_NONE) + pi->conf_state |= L2CAP_CONF_NO_FCS_RECV; + + break; + default: if (hint) break; @@ -2636,6 +2688,10 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr goto unlock; if (l2cap_pi(sk)->conf_state & L2CAP_CONF_INPUT_DONE) { + if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_NO_FCS_RECV) + || l2cap_pi(sk)->fcs != L2CAP_FCS_NONE) + l2cap_pi(sk)->fcs = L2CAP_FCS_CRC16; + sk->sk_state = BT_CONNECTED; l2cap_pi(sk)->next_tx_seq = 0; l2cap_pi(sk)->expected_ack_seq = 0; @@ -2720,6 +2776,10 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr l2cap_pi(sk)->conf_state |= L2CAP_CONF_INPUT_DONE; if (l2cap_pi(sk)->conf_state & L2CAP_CONF_OUTPUT_DONE) { + if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_NO_FCS_RECV) + || l2cap_pi(sk)->fcs != L2CAP_FCS_NONE) + l2cap_pi(sk)->fcs = L2CAP_FCS_CRC16; + sk->sk_state = BT_CONNECTED; l2cap_pi(sk)->expected_tx_seq = 0; l2cap_pi(sk)->num_to_ack = 0; @@ -2807,7 +2867,8 @@ static inline int l2cap_information_req(struct l2cap_conn *conn, struct l2cap_cm rsp->type = cpu_to_le16(L2CAP_IT_FEAT_MASK); rsp->result = cpu_to_le16(L2CAP_IR_SUCCESS); if (enable_ertm) - feat_mask |= L2CAP_FEAT_ERTM | L2CAP_FEAT_STREAMING; + feat_mask |= L2CAP_FEAT_ERTM | L2CAP_FEAT_STREAMING + | L2CAP_FEAT_FCS; put_unaligned(cpu_to_le32(feat_mask), (__le32 *) rsp->data); l2cap_send_cmd(conn, cmd->ident, L2CAP_INFO_RSP, sizeof(buf), buf); @@ -2959,6 +3020,22 @@ static inline void l2cap_sig_channel(struct l2cap_conn *conn, struct sk_buff *sk kfree_skb(skb); } +static int l2cap_check_fcs(struct l2cap_pinfo *pi, struct sk_buff *skb) +{ + u16 our_fcs, rcv_fcs; + int hdr_size = L2CAP_HDR_SIZE + 2; + + if (pi->fcs == L2CAP_FCS_CRC16) { + skb_trim(skb, skb->len - 2); + rcv_fcs = get_unaligned_le16(skb->data + skb->len); + our_fcs = crc16(0, skb->data - hdr_size, skb->len + hdr_size); + + if (our_fcs != rcv_fcs) + return -EINVAL; + } + return 0; +} + static int l2cap_sar_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 control) { struct l2cap_pinfo *pi = l2cap_pi(sk); @@ -3169,6 +3246,9 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk if (__is_sar_start(control)) len -= 2; + if (pi->fcs == L2CAP_FCS_CRC16) + len -= 2; + /* * We can just drop the corrupted I-frame here. * Receiver will miss it and start proper recovery @@ -3177,6 +3257,9 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk if (len > L2CAP_DEFAULT_MAX_PDU_SIZE) goto drop; + if (l2cap_check_fcs(pi, skb)) + goto drop; + if (__is_iframe(control)) err = l2cap_data_channel_iframe(sk, control, skb); else @@ -3194,9 +3277,15 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk if (__is_sar_start(control)) len -= 2; + if (pi->fcs == L2CAP_FCS_CRC16) + len -= 2; + if (len > L2CAP_DEFAULT_MAX_PDU_SIZE || __is_sframe(control)) goto drop; + if (l2cap_check_fcs(pi, skb)) + goto drop; + tx_seq = __get_txseq(control); if (pi->expected_tx_seq == tx_seq) -- 1.6.3.3