Re: [net-next PATCH v2 1/2] net: pktgen: support injecting packets for qdisc testing

[David Miller]

From: John Fastabend 
Date: Sat, 02 Jul 2016 14:12:54 -0700

> 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 

Applied.

[net-next PATCH v2 1/2] net: pktgen: support injecting packets for qdisc testing

[John Fastabend]

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 
---
 net/core/pktgen.c |   42 --
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f74ab9c..bbd118b 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_RECEIVE1   /* 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(_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);

Re: [net-next PATCH v2 1/2] net: pktgen: support injecting packets for qdisc testing

[John Fastabend]

On 16-06-30 01:37 AM, Jesper Dangaard Brouer wrote:
> On Wed, 29 Jun 2016 13:03:06 -0700
> John Fastabend  wrote:
> 
>> 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 
> 
> I generally like this.
> 

[...]

>> @@ -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_add(burst, _dev->skb->users);
> 
> Reading the code, people might think that "burst" is allowed for this
> mode, which it is not. (You do handle this earlier in this patch when
> configuring this mode).

Right we never get here without burst == 1 but sure it does read
a bit strange I'll use atomic_inc().


Thanks,
John

Re: [net-next PATCH v2 1/2] net: pktgen: support injecting packets for qdisc testing

[Jesper Dangaard Brouer]

On Wed, 29 Jun 2016 13:03:06 -0700
John Fastabend  wrote:

> 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 

I generally like this.

>  net/core/pktgen.c |   42 --
>  1 file changed, 40 insertions(+), 2 deletions(-)
> 
> diff --git a/net/core/pktgen.c b/net/core/pktgen.c
> index f74ab9c..4b3d467 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_add(burst, _dev->skb->users);

Reading the code, people might think that "burst" is allowed for this
mode, which it is not. (You do handle this earlier in this patch when
configuring this mode).

> + 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);
> 



-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

[net-next PATCH v2 1/2] net: pktgen: support injecting packets for qdisc testing

[John Fastabend]

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 
---
 net/core/pktgen.c |   42 --
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f74ab9c..4b3d467 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_RECEIVE1   /* 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_add(burst, _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);