net: pktgen: support injecting packets for qdisc testing

Add another xmit_mode to pktgen to allow testing xmit functionality
of qdiscs. The new mode "queue_xmit" injects packets at
__dev_queue_xmit() so that qdisc is called.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 40 insertions, 2 deletions

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f74ab9c3b38f..bbd118b19aef 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -213,6 +213,7 @@
 /* Xmit modes */
 #define M_START_XMIT            0       /* Default normal TX */
 #define M_NETIF_RECEIVE         1       /* Inject packets into stack */
+#define M_QUEUE_XMIT            2       /* Inject packet into qdisc */
 
 /* If lock -- protects updating of if_list */
 #define   if_lock(t)           spin_lock(&(t->if_lock));
@@ -626,6 +627,8 @@ static int pktgen_if_show(struct seq_file *seq, void *v)
 
         if (pkt_dev->xmit_mode == M_NETIF_RECEIVE)
                 seq_puts(seq, "     xmit_mode: netif_receive\n");
+        else if (pkt_dev->xmit_mode == M_QUEUE_XMIT)
+                seq_puts(seq, "     xmit_mode: xmit_queue\n");
 
         seq_puts(seq, "     Flags: ");
 
@@ -1142,8 +1145,10 @@ static ssize_t pktgen_if_write(struct file *file,
                         return len;
 
                 i += len;
-                if ((value > 1) && (pkt_dev->xmit_mode == M_START_XMIT) &&
-                    (!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))
+                if ((value > 1) &&
+                    ((pkt_dev->xmit_mode == M_QUEUE_XMIT) ||
+                     ((pkt_dev->xmit_mode == M_START_XMIT) &&
+                     (!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))))
                         return -ENOTSUPP;
                 pkt_dev->burst = value < 1 ? 1 : value;
                 sprintf(pg_result, "OK: burst=%d", pkt_dev->burst);
@@ -1198,6 +1203,9 @@ static ssize_t pktgen_if_write(struct file *file,
                          * at module loading time
                          */
                         pkt_dev->clone_skb = 0;
+                } else if (strcmp(f, "queue_xmit") == 0) {
+                        pkt_dev->xmit_mode = M_QUEUE_XMIT;
+                        pkt_dev->last_ok = 1;
                 } else {
                         sprintf(pg_result,
                                 "xmit_mode -:%s:- unknown\nAvailable modes: %s",
@@ -3434,6 +3442,36 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
 #endif
                 } while (--burst > 0);
                 goto out; /* Skips xmit_mode M_START_XMIT */
+        } else if (pkt_dev->xmit_mode == M_QUEUE_XMIT) {
+                local_bh_disable();
+                atomic_inc(&pkt_dev->skb->users);
+
+                ret = dev_queue_xmit(pkt_dev->skb);
+                switch (ret) {
+                case NET_XMIT_SUCCESS:
+                        pkt_dev->sofar++;
+                        pkt_dev->seq_num++;
+                        pkt_dev->tx_bytes += pkt_dev->last_pkt_size;
+                        break;
+                case NET_XMIT_DROP:
+                case NET_XMIT_CN:
+                /* These are all valid return codes for a qdisc but
+                 * indicate packets are being dropped or will likely
+                 * be dropped soon.
+                 */
+                case NETDEV_TX_BUSY:
+                /* qdisc may call dev_hard_start_xmit directly in cases
+                 * where no queues exist e.g. loopback device, virtual
+                 * devices, etc. In this case we need to handle
+                 * NETDEV_TX_ codes.
+                 */
+                default:
+                        pkt_dev->errors++;
+                        net_info_ratelimited("%s xmit error: %d\n",
+                                             pkt_dev->odevname, ret);
+                        break;
+                }
+                goto out;
         }
 
         txq = skb_get_tx_queue(odev, pkt_dev->skb);