netmap: bridge: fix NS_MOREFRAG support

Support for NS_MOREFRAG is broken, as NS_MOREFRAG is copied from
the TX slot to the RX slot rather than the other way around.
Also, the NS_MOREFRAG must be copied also in case of packet
copy (no zerocopy).

Reported by:	rajesh1.kumar_amd.com
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D27980

1 files changed, 7 insertions, 5 deletions

diff --git a/tools/tools/netmap/bridge.c b/tools/tools/netmap/bridge.c
index af8c2847130a..77d235bf6e08 100644
--- a/tools/tools/netmap/bridge.c
+++ b/tools/tools/netmap/bridge.c
@@ -86,13 +86,12 @@ rings_move(struct netmap_ring *rxring, struct netmap_ring *txring,
 		struct netmap_slot *rs = &rxring->slot[j];
 		struct netmap_slot *ts = &txring->slot[k];
 
-		/* swap packets */
 		if (ts->buf_idx < 2 || rs->buf_idx < 2) {
 			RD(2, "wrong index rxr[%d] = %d  -> txr[%d] = %d",
 			    j, rs->buf_idx, k, ts->buf_idx);
 			sleep(2);
 		}
-		/* copy the packet length. */
+		/* Copy the packet length. */
 		if (rs->len > rxring->nr_buf_size) {
 			RD(2,  "%s: invalid len %u, rxr[%d] -> txr[%d]",
 			    msg, rs->len, j, k);
@@ -109,13 +108,16 @@ rings_move(struct netmap_ring *rxring, struct netmap_ring *txring,
 			/* report the buffer change. */
 			ts->flags |= NS_BUF_CHANGED;
 			rs->flags |= NS_BUF_CHANGED;
-			/* copy the NS_MOREFRAG */
-			rs->flags = (rs->flags & ~NS_MOREFRAG) | (ts->flags & NS_MOREFRAG);
 		} else {
 			char *rxbuf = NETMAP_BUF(rxring, rs->buf_idx);
 			char *txbuf = NETMAP_BUF(txring, ts->buf_idx);
 			nm_pkt_copy(rxbuf, txbuf, ts->len);
 		}
+		/*
+		 * Copy the NS_MOREFRAG from rs to ts, leaving any
+		 * other flags unchanged.
+		 */
+		ts->flags = (ts->flags & ~NS_MOREFRAG) | (rs->flags & NS_MOREFRAG);
 		j = nm_ring_next(rxring, j);
 		k = nm_ring_next(txring, k);
 	}
@@ -190,7 +192,7 @@ usage(void)
 int
 main(int argc, char **argv)
 {
-	char msg_a2b[128], msg_b2a[128];
+	char msg_a2b[256], msg_b2a[256];
 	struct pollfd pollfd[2];
 	u_int burst = 1024, wait_link = 4;
 	struct nmport_d *pa = NULL, *pb = NULL;