[commits] [git] batman-adv branch, linux, updated. 5ff6d9f73e1a8751740bc537732d05a99dfbc01b

postmaster at open-mesh.net postmaster at open-mesh.net
Mon Nov 9 02:02:22 UTC 2009


The following commit has been merged in the linux branch:
commit 9652041da18a1a1d9a0b7ebd9eef16bd712be38a
Author: Krzysztof Halasa <khc at pm.waw.pl>
Date:   Fri Oct 9 06:16:10 2009 +0000

    WAN: fix Cisco HDLC handshaking.
    
    Cisco HDLC uses keepalive packets and sequence numbers to determine link
    state. In rare cases both ends could transmit keepalive packets at the same
    time, causing the received sequence numbers to be treated as incorrect.
    Now we accept our current sequence number as well as the previous one.
    
    Signed-off-by: Krzysztof Hałasa <khc at pm.waw.pl>
    Signed-off-by: David S. Miller <davem at davemloft.net>

diff --git a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c
index cf5fd17..f1bff98 100644
--- a/drivers/net/wan/hdlc_cisco.c
+++ b/drivers/net/wan/hdlc_cisco.c
@@ -58,8 +58,7 @@ struct cisco_state {
 	spinlock_t lock;
 	unsigned long last_poll;
 	int up;
-	int request_sent;
-	u32 txseq; /* TX sequence number */
+	u32 txseq; /* TX sequence number, 0 = none */
 	u32 rxseq; /* RX sequence number */
 };
 
@@ -163,6 +162,7 @@ static int cisco_rx(struct sk_buff *skb)
 	struct cisco_packet *cisco_data;
 	struct in_device *in_dev;
 	__be32 addr, mask;
+	u32 ack;
 
 	if (skb->len < sizeof(struct hdlc_header))
 		goto rx_error;
@@ -223,8 +223,10 @@ static int cisco_rx(struct sk_buff *skb)
 		case CISCO_KEEPALIVE_REQ:
 			spin_lock(&st->lock);
 			st->rxseq = ntohl(cisco_data->par1);
-			if (st->request_sent &&
-			    ntohl(cisco_data->par2) == st->txseq) {
+			ack = ntohl(cisco_data->par2);
+			if (ack && (ack == st->txseq ||
+				    /* our current REQ may be in transit */
+				    ack == st->txseq - 1)) {
 				st->last_poll = jiffies;
 				if (!st->up) {
 					u32 sec, min, hrs, days;
@@ -275,7 +277,6 @@ static void cisco_timer(unsigned long arg)
 
 	cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 			     htonl(st->rxseq));
-	st->request_sent = 1;
 	spin_unlock(&st->lock);
 
 	st->timer.expires = jiffies + st->settings.interval * HZ;
@@ -293,9 +294,7 @@ static void cisco_start(struct net_device *dev)
 	unsigned long flags;
 
 	spin_lock_irqsave(&st->lock, flags);
-	st->up = 0;
-	st->request_sent = 0;
-	st->txseq = st->rxseq = 0;
+	st->up = st->txseq = st->rxseq = 0;
 	spin_unlock_irqrestore(&st->lock, flags);
 
 	init_timer(&st->timer);
@@ -317,8 +316,7 @@ static void cisco_stop(struct net_device *dev)
 
 	spin_lock_irqsave(&st->lock, flags);
 	netif_dormant_on(dev);
-	st->up = 0;
-	st->request_sent = 0;
+	st->up = st->txseq = 0;
 	spin_unlock_irqrestore(&st->lock, flags);
 }
 

-- 
batman-adv


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