1 files changed, 85 insertions, 66 deletions

diff --git a/net/dccp/output.c b/net/dccp/output.c
index c8d843e983fc..f49544618f20 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -61,6 +61,7 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 			set_ack = 0;
 			/* fall through */
 		case DCCP_PKT_DATAACK:
+		case DCCP_PKT_RESET:
 			break;
 
 		case DCCP_PKT_REQUEST:
@@ -69,12 +70,14 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 
 		case DCCP_PKT_SYNC:
 		case DCCP_PKT_SYNCACK:
-			ackno = dcb->dccpd_seq;
+			ackno = dcb->dccpd_ack_seq;
 			/* fall through */
 		default:
 			/*
-			 * Only data packets should come through with skb->sk
-			 * set.
+			 * Set owner/destructor: some skbs are allocated via
+			 * alloc_skb (e.g. when retransmission may happen).
+			 * Only Data, DataAck, and Reset packets should come
+			 * through here with skb->sk set.
 			 */
 			WARN_ON(skb->sk);
 			skb_set_owner_w(skb, sk);
@@ -174,34 +177,38 @@ void dccp_write_space(struct sock *sk)
 
 /**
  * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
- * @sk: socket to wait for
+ * @sk:    socket to wait for
+ * @skb:   current skb to pass on for waiting
+ * @delay: sleep timeout in milliseconds (> 0)
+ * This function is called by default when the socket is closed, and
+ * when a non-zero linger time is set on the socket. For consistency
  */
-static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb)
+static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 	DEFINE_WAIT(wait);
-	unsigned long delay;
+	unsigned long jiffdelay;
 	int rc;
 
-	while (1) {
+	do {
+		dccp_pr_debug("delayed send by %d msec\n", delay);
+		jiffdelay = msecs_to_jiffies(delay);
+
 		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
 
+		sk->sk_write_pending++;
+		release_sock(sk);
+		schedule_timeout(jiffdelay);
+		lock_sock(sk);
+		sk->sk_write_pending--;
+
 		if (sk->sk_err)
 			goto do_error;
 		if (signal_pending(current))
 			goto do_interrupted;
 
 		rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
-		if (rc <= 0)
-			break;
-		dccp_pr_debug("delayed send by %d msec\n", rc);
-		delay = msecs_to_jiffies(rc);
-		sk->sk_write_pending++;
-		release_sock(sk);
-		schedule_timeout(delay);
-		lock_sock(sk);
-		sk->sk_write_pending--;
-	}
+	} while ((delay = rc) > 0);
 out:
 	finish_wait(sk->sk_sleep, &wait);
 	return rc;
@@ -228,7 +235,7 @@ void dccp_write_xmit(struct sock *sk, int block)
 						msecs_to_jiffies(err)+jiffies);
 				break;
 			} else
-				err = dccp_wait_for_ccid(sk, skb);
+				err = dccp_wait_for_ccid(sk, skb, err);
 			if (err && err != -EINTR)
 				DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
 		}
@@ -324,72 +331,81 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
 
 EXPORT_SYMBOL_GPL(dccp_make_response);
 
-static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
-				       const enum dccp_reset_codes code)
+/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
+struct sk_buff *dccp_ctl_make_reset(struct socket *ctl, struct sk_buff *rcv_skb)
 {
-	struct dccp_hdr *dh;
-	struct dccp_sock *dp = dccp_sk(sk);
-	const u32 dccp_header_size = sizeof(struct dccp_hdr) +
-				     sizeof(struct dccp_hdr_ext) +
-				     sizeof(struct dccp_hdr_reset);
-	struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
-					   GFP_ATOMIC);
-	if (skb == NULL)
-		return NULL;
-
-	/* Reserve space for headers. */
-	skb_reserve(skb, sk->sk_prot->max_header);
-
-	skb->dst = dst_clone(dst);
-
-	dccp_inc_seqno(&dp->dccps_gss);
-
-	DCCP_SKB_CB(skb)->dccpd_reset_code = code;
-	DCCP_SKB_CB(skb)->dccpd_type	   = DCCP_PKT_RESET;
-	DCCP_SKB_CB(skb)->dccpd_seq	   = dp->dccps_gss;
+	struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
+	struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
+	const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
+				       sizeof(struct dccp_hdr_ext) +
+				       sizeof(struct dccp_hdr_reset);
+	struct dccp_hdr_reset *dhr;
+	struct sk_buff *skb;
 
-	if (dccp_insert_options(sk, skb)) {
-		kfree_skb(skb);
+	skb = alloc_skb(ctl->sk->sk_prot->max_header, GFP_ATOMIC);
+	if (skb == NULL)
 		return NULL;
-	}
 
-	dh = dccp_zeroed_hdr(skb, dccp_header_size);
+	skb_reserve(skb, ctl->sk->sk_prot->max_header);
 
-	dh->dccph_sport	= inet_sk(sk)->sport;
-	dh->dccph_dport	= inet_sk(sk)->dport;
-	dh->dccph_doff	= (dccp_header_size +
-			   DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
+	/* Swap the send and the receive. */
+	dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
 	dh->dccph_type	= DCCP_PKT_RESET;
+	dh->dccph_sport	= rxdh->dccph_dport;
+	dh->dccph_dport	= rxdh->dccph_sport;
+	dh->dccph_doff	= dccp_hdr_reset_len / 4;
 	dh->dccph_x	= 1;
-	dccp_hdr_set_seq(dh, dp->dccps_gss);
-	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
 
-	dccp_hdr_reset(skb)->dccph_reset_code = code;
-	inet_csk(sk)->icsk_af_ops->send_check(sk, 0, skb);
+	dhr = dccp_hdr_reset(skb);
+	dhr->dccph_reset_code = dcb->dccpd_reset_code;
+
+	switch (dcb->dccpd_reset_code) {
+	case DCCP_RESET_CODE_PACKET_ERROR:
+		dhr->dccph_reset_data[0] = rxdh->dccph_type;
+		break;
+	case DCCP_RESET_CODE_OPTION_ERROR:	/* fall through */
+	case DCCP_RESET_CODE_MANDATORY_ERROR:
+		memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
+		break;
+	}
+	/*
+	 * From RFC 4340, 8.3.1:
+	 *   If P.ackno exists, set R.seqno := P.ackno + 1.
+	 *   Else set R.seqno := 0.
+	 */
+	if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+		dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
+	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
 
-	DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+	dccp_csum_outgoing(skb);
 	return skb;
 }
 
+EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
+
+/* send Reset on established socket, to close or abort the connection */
 int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
 {
+	struct sk_buff *skb;
 	/*
 	 * FIXME: what if rebuild_header fails?
 	 * Should we be doing a rebuild_header here?
 	 */
 	int err = inet_sk_rebuild_header(sk);
 
-	if (err == 0) {
-		struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
-						      code);
-		if (skb != NULL) {
-			memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
-			err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, 0);
-			return net_xmit_eval(err);
-		}
-	}
+	if (err != 0)
+		return err;
+
+	skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
+	if (skb == NULL)
+		return -ENOBUFS;
 
-	return err;
+	/* Reserve space for headers and prepare control bits. */
+	skb_reserve(skb, sk->sk_prot->max_header);
+	DCCP_SKB_CB(skb)->dccpd_type	   = DCCP_PKT_RESET;
+	DCCP_SKB_CB(skb)->dccpd_reset_code = code;
+
+	return dccp_transmit_skb(sk, skb);
 }
 
 /*
@@ -477,6 +493,7 @@ void dccp_send_ack(struct sock *sk)
 
 EXPORT_SYMBOL_GPL(dccp_send_ack);
 
+/* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
 void dccp_send_delayed_ack(struct sock *sk)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
@@ -507,7 +524,7 @@ void dccp_send_delayed_ack(struct sock *sk)
 	sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
 }
 
-void dccp_send_sync(struct sock *sk, const u64 seq,
+void dccp_send_sync(struct sock *sk, const u64 ackno,
 		    const enum dccp_pkt_type pkt_type)
 {
 	/*
@@ -517,14 +534,16 @@ void dccp_send_sync(struct sock *sk, const u64 seq,
 	 */
 	struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
 
-	if (skb == NULL)
+	if (skb == NULL) {
 		/* FIXME: how to make sure the sync is sent? */
+		DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type));
 		return;
+	}
 
 	/* Reserve space for headers and prepare control bits. */
 	skb_reserve(skb, sk->sk_prot->max_header);
 	DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
-	DCCP_SKB_CB(skb)->dccpd_seq = seq;
+	DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;
 
 	dccp_transmit_skb(sk, skb);
 }