1 files changed, 124 insertions, 10 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 52d23b3ffaf5..5aee1ed23ba9 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -246,6 +246,10 @@ static int tipc_link_build_nack_msg(struct tipc_link *l,
 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
 					struct sk_buff_head *xmitq);
 static bool tipc_link_release_pkts(struct tipc_link *l, u16 to);
+static u16 tipc_build_gap_ack_blks(struct tipc_link *l, void *data);
+static void tipc_link_advance_transmq(struct tipc_link *l, u16 acked, u16 gap,
+				      struct tipc_gap_ack_blks *ga,
+				      struct sk_buff_head *xmitq);
 
 /*
  *  Simple non-static link routines (i.e. referenced outside this file)
@@ -1226,6 +1230,102 @@ static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
 	return released;
 }
 
+/* tipc_build_gap_ack_blks - build Gap ACK blocks
+ * @l: tipc link that data have come with gaps in sequence if any
+ * @data: data buffer to store the Gap ACK blocks after built
+ *
+ * returns the actual allocated memory size
+ */
+static u16 tipc_build_gap_ack_blks(struct tipc_link *l, void *data)
+{
+	struct sk_buff *skb = skb_peek(&l->deferdq);
+	struct tipc_gap_ack_blks *ga = data;
+	u16 len, expect, seqno = 0;
+	u8 n = 0;
+
+	if (!skb)
+		goto exit;
+
+	expect = buf_seqno(skb);
+	skb_queue_walk(&l->deferdq, skb) {
+		seqno = buf_seqno(skb);
+		if (unlikely(more(seqno, expect))) {
+			ga->gacks[n].ack = htons(expect - 1);
+			ga->gacks[n].gap = htons(seqno - expect);
+			if (++n >= MAX_GAP_ACK_BLKS) {
+				pr_info_ratelimited("Too few Gap ACK blocks!\n");
+				goto exit;
+			}
+		} else if (unlikely(less(seqno, expect))) {
+			pr_warn("Unexpected skb in deferdq!\n");
+			continue;
+		}
+		expect = seqno + 1;
+	}
+
+	/* last block */
+	ga->gacks[n].ack = htons(seqno);
+	ga->gacks[n].gap = 0;
+	n++;
+
+exit:
+	len = tipc_gap_ack_blks_sz(n);
+	ga->len = htons(len);
+	ga->gack_cnt = n;
+	return len;
+}
+
+/* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
+ *			       acked packets, also doing retransmissions if
+ *			       gaps found
+ * @l: tipc link with transmq queue to be advanced
+ * @acked: seqno of last packet acked by peer without any gaps before
+ * @gap: # of gap packets
+ * @ga: buffer pointer to Gap ACK blocks from peer
+ * @xmitq: queue for accumulating the retransmitted packets if any
+ */
+static void tipc_link_advance_transmq(struct tipc_link *l, u16 acked, u16 gap,
+				      struct tipc_gap_ack_blks *ga,
+				      struct sk_buff_head *xmitq)
+{
+	struct sk_buff *skb, *_skb, *tmp;
+	struct tipc_msg *hdr;
+	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
+	u16 ack = l->rcv_nxt - 1;
+	u16 seqno;
+	u16 n = 0;
+
+	skb_queue_walk_safe(&l->transmq, skb, tmp) {
+		seqno = buf_seqno(skb);
+
+next_gap_ack:
+		if (less_eq(seqno, acked)) {
+			/* release skb */
+			__skb_unlink(skb, &l->transmq);
+			kfree_skb(skb);
+		} else if (less_eq(seqno, acked + gap)) {
+			/* retransmit skb */
+			_skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
+			if (!_skb)
+				continue;
+			hdr = buf_msg(_skb);
+			msg_set_ack(hdr, ack);
+			msg_set_bcast_ack(hdr, bc_ack);
+			_skb->priority = TC_PRIO_CONTROL;
+			__skb_queue_tail(xmitq, _skb);
+			l->stats.retransmitted++;
+		} else {
+			/* retry with Gap ACK blocks if any */
+			if (!ga || n >= ga->gack_cnt)
+				break;
+			acked = ntohs(ga->gacks[n].ack);
+			gap = ntohs(ga->gacks[n].gap);
+			n++;
+			goto next_gap_ack;
+		}
+	}
+}
+
 /* tipc_link_build_state_msg: prepare link state message for transmission
  *
  * Note that sending of broadcast ack is coordinated among nodes, to reduce
@@ -1378,6 +1478,7 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 	struct tipc_mon_state *mstate = &l->mon_state;
 	int dlen = 0;
 	void *data;
+	u16 glen = 0;
 
 	/* Don't send protocol message during reset or link failover */
 	if (tipc_link_is_blocked(l))
@@ -1390,8 +1491,8 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
 
 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
-			      tipc_max_domain_size, l->addr,
-			      tipc_own_addr(l->net), 0, 0, 0);
+			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
+			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
 	if (!skb)
 		return;
 
@@ -1418,9 +1519,11 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 		msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
 		msg_set_probe(hdr, probe);
 		msg_set_is_keepalive(hdr, probe || probe_reply);
-		tipc_mon_prep(l->net, data, &dlen, mstate, l->bearer_id);
-		msg_set_size(hdr, INT_H_SIZE + dlen);
-		skb_trim(skb, INT_H_SIZE + dlen);
+		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
+			glen = tipc_build_gap_ack_blks(l, data);
+		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
+		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
+		skb_trim(skb, INT_H_SIZE + glen + dlen);
 		l->stats.sent_states++;
 		l->rcv_unacked = 0;
 	} else {
@@ -1590,6 +1693,7 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 			       struct sk_buff_head *xmitq)
 {
 	struct tipc_msg *hdr = buf_msg(skb);
+	struct tipc_gap_ack_blks *ga = NULL;
 	u16 rcvgap = 0;
 	u16 ack = msg_ack(hdr);
 	u16 gap = msg_seq_gap(hdr);
@@ -1600,6 +1704,7 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 	u16 dlen = msg_data_sz(hdr);
 	int mtyp = msg_type(hdr);
 	bool reply = msg_probe(hdr);
+	u16 glen = 0;
 	void *data;
 	char *if_name;
 	int rc = 0;
@@ -1697,7 +1802,17 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 				rc = TIPC_LINK_UP_EVT;
 			break;
 		}
-		tipc_mon_rcv(l->net, data, dlen, l->addr,
+
+		/* Receive Gap ACK blocks from peer if any */
+		if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
+			ga = (struct tipc_gap_ack_blks *)data;
+			glen = ntohs(ga->len);
+			/* sanity check: if failed, ignore Gap ACK blocks */
+			if (glen != tipc_gap_ack_blks_sz(ga->gack_cnt))
+				ga = NULL;
+		}
+
+		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
 			     &l->mon_state, l->bearer_id);
 
 		/* Send NACK if peer has sent pkts we haven't received yet */
@@ -1706,13 +1821,12 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 		if (rcvgap || reply)
 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
 						  rcvgap, 0, 0, xmitq);
-		tipc_link_release_pkts(l, ack);
+
+		tipc_link_advance_transmq(l, ack, gap, ga, xmitq);
 
 		/* If NACK, retransmit will now start at right position */
-		if (gap) {
-			rc = tipc_link_retrans(l, l, ack + 1, ack + gap, xmitq);
+		if (gap)
 			l->stats.recv_nacks++;
-		}
 
 		tipc_link_advance_backlog(l, xmitq);
 		if (unlikely(!skb_queue_empty(&l->wakeupq)))