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>

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f74ab9c3b38fe10610b3a4e8610ed78bc0d8437a..bbd118b19aef7fbe468604f8f04859ac00040df7 100644 (file)
--- 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);