@@ -611,6 +611,7 @@ static int tipc_bcbearer_send(struct sk_buff *buf,
struct tipc_bearer *p = bcbearer->bpairs[bp_index].primary;
struct tipc_bearer *b = p;
struct tipc_bearer *s = bcbearer->bpairs[bp_index].secondary;
+ struct sk_buff *tbuf;
if (!p)
break; /* No more bearers to try */
@@ -626,7 +627,17 @@ static int tipc_bcbearer_send(struct sk_buff *buf,
if (bcbearer->remains_new.count == bcbearer->remains.count)
continue; /* Nothing added by bearer pair */
- tipc_bearer_send(b, buf, &s->media->bcast_addr);
+ if (bp_index == 0) {
+ /* Use original buffer for first bearer */
+ tipc_bearer_send(b, buf, &b->media->bcast_addr);
+ } else {
+ /* Avoid concurrent buffer access */
+ tbuf = pskb_copy(buf, GFP_ATOMIC);
+ if (!tbuf)
+ break;
+ tipc_bearer_send(b, tbuf, &b->media->bcast_addr);
+ kfree_skb(tbuf); /* Bearer keeps a clone */
+ }
/* Swap bearers for next packet */
if (s) {
When sending packets, TIPC bearers use skb_clone() before writing their hardware header. This will however NOT copy the data buffer. So when the same packet is sent over multiple bearers (to reach multiple nodes), the same socket buffer data will be treated by multiple tipc_media drivers which will write their own hardware header through dev_hard_header(). Most of the time this is not a problem, because by the time the packet is processed by the second media, it has already been sent over the first one. However, when the first transmission is delayed (e.g. because of insufficient bandwidth or through a shaper), the next bearer will overwrite the hardware header, resulting in the packet being sent: a) with the wrong source address, when bearers of the same type, e.g. ethernet, are involved b) with a completely corrupt header, or even dropped, when bearers of different types are involved. So when the same socket buffer is to be sent multiple times, send a pskb_copy() instead (from the second instance on), and release it afterwards (the bearer will skb_clone() it anyway). Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com> --- net/tipc/bcast.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)