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[PATCH v2] net/vmnet: Pad short Ethernet frames

William Hooper posted 1 patch 3 months, 1 week ago
There is a newer version of this series
net/vmnet-common.m | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
[PATCH v2] net/vmnet: Pad short Ethernet frames
Posted by William Hooper 3 months, 1 week ago 
At least on macOS 12.7.2, vmnet doesn't pad Ethernet frames, such as the
host's ARP replies, to the minimum size (60 bytes before the frame check
sequence) defined in IEEE Std 802.3-2022, so guests' Ethernet device
drivers may drop them with "frame too short" errors.

This patch calls eth_pad_short_frame() to add padding, as in net/tap.c
and net/slirp.c. Thanks to Bin Meng and Philippe Mathieu-Daudé for
reviewing an earlier version.

Signed-off-by: William Hooper <wsh@wshooper.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2058
---
 net/vmnet-common.m | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/net/vmnet-common.m b/net/vmnet-common.m
index 30c4e53c13..bce1cc590d 100644
--- a/net/vmnet-common.m
+++ b/net/vmnet-common.m
@@ -18,6 +18,7 @@
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "sysemu/runstate.h"
+#include "net/eth.h"
 
 #include <vmnet/vmnet.h>
 #include <dispatch/dispatch.h>
@@ -147,10 +148,25 @@ static int vmnet_read_packets(VmnetState *s)
  */
 static void vmnet_write_packets_to_qemu(VmnetState *s)
 {
+    uint8_t *pkt;
+    size_t pktsz;
+    uint8_t min_pkt[ETH_ZLEN];
+    size_t min_pktsz;
+
     while (s->packets_send_current_pos < s->packets_send_end_pos) {
-        ssize_t size = qemu_send_packet_async(&s->nc,
-                                      s->iov_buf[s->packets_send_current_pos].iov_base,
-                                      s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
+        pkt = s->iov_buf[s->packets_send_current_pos].iov_base;
+        pktsz = s->packets_buf[s->packets_send_current_pos].vm_pkt_size;
+
+        if (net_peer_needs_padding(&s->nc)) {
+            min_pktsz = sizeof(min_pkt);
+
+            if (eth_pad_short_frame(min_pkt, &min_pktsz, pkt, pktsz)) {
+                pkt = min_pkt;
+                pktsz = min_pktsz;
+            }
+        }
+
+        ssize_t size = qemu_send_packet_async(&s->nc, pkt, pktsz,
                                       vmnet_send_completed);
 
         if (size == 0) {
-- 
2.37.1
Ping: [PATCH v2] net/vmnet: Pad short Ethernet frames
Posted by William Hooper 1 month ago 
On Sat, Aug 17, 2024 at 11:33 PM William Hooper <wsh@wshooper.org> wrote:
> At least on macOS 12.7.2, vmnet doesn't pad Ethernet frames, such as the
> host's ARP replies, to the minimum size (60 bytes before the frame check
> sequence) defined in IEEE Std 802.3-2022, so guests' Ethernet device
> drivers may drop them with "frame too short" errors.
>
> This patch calls eth_pad_short_frame() to add padding, as in net/tap.c
> and net/slirp.c. Thanks to Bin Meng and Philippe Mathieu-Daudé for
> reviewing an earlier version.
>
> Signed-off-by: William Hooper <wsh@wshooper.org>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2058
> ---
>  net/vmnet-common.m | 22 +++++++++++++++++++---
>  1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/net/vmnet-common.m b/net/vmnet-common.m
> index 30c4e53c13..bce1cc590d 100644
> --- a/net/vmnet-common.m
> +++ b/net/vmnet-common.m
> @@ -18,6 +18,7 @@
>  #include "qemu/error-report.h"
>  #include "qapi/error.h"
>  #include "sysemu/runstate.h"
> +#include "net/eth.h"
>
>  #include <vmnet/vmnet.h>
>  #include <dispatch/dispatch.h>
> @@ -147,10 +148,25 @@ static int vmnet_read_packets(VmnetState *s)
>   */
>  static void vmnet_write_packets_to_qemu(VmnetState *s)
>  {
> +    uint8_t *pkt;
> +    size_t pktsz;
> +    uint8_t min_pkt[ETH_ZLEN];
> +    size_t min_pktsz;
> +
>      while (s->packets_send_current_pos < s->packets_send_end_pos) {
> -        ssize_t size = qemu_send_packet_async(&s->nc,
> -                                      s->iov_buf[s->packets_send_current_pos].iov_base,
> -                                      s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
> +        pkt = s->iov_buf[s->packets_send_current_pos].iov_base;
> +        pktsz = s->packets_buf[s->packets_send_current_pos].vm_pkt_size;
> +
> +        if (net_peer_needs_padding(&s->nc)) {
> +            min_pktsz = sizeof(min_pkt);
> +
> +            if (eth_pad_short_frame(min_pkt, &min_pktsz, pkt, pktsz)) {
> +                pkt = min_pkt;
> +                pktsz = min_pktsz;
> +            }
> +        }
> +
> +        ssize_t size = qemu_send_packet_async(&s->nc, pkt, pktsz,
>                                        vmnet_send_completed);
>
>          if (size == 0) {
> --
> 2.37.1

Ping?
Re: Ping: [PATCH v2] net/vmnet: Pad short Ethernet frames
Posted by Phil Dennis-Jordan 3 weeks, 3 days ago 
On Sun, 20 Oct 2024 at 05:17, William Hooper <wsh@wshooper.org> wrote:
>
> On Sat, Aug 17, 2024 at 11:33 PM William Hooper <wsh@wshooper.org> wrote:
> > At least on macOS 12.7.2, vmnet doesn't pad Ethernet frames, such as the
> > host's ARP replies, to the minimum size (60 bytes before the frame check
> > sequence) defined in IEEE Std 802.3-2022, so guests' Ethernet device
> > drivers may drop them with "frame too short" errors.
> >
> > This patch calls eth_pad_short_frame() to add padding, as in net/tap.c
> > and net/slirp.c. Thanks to Bin Meng and Philippe Mathieu-Daudé for
> > reviewing an earlier version.
> >
> > Signed-off-by: William Hooper <wsh@wshooper.org>
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2058
> > ---
> >  net/vmnet-common.m | 22 +++++++++++++++++++---
> >  1 file changed, 19 insertions(+), 3 deletions(-)
> >
> > diff --git a/net/vmnet-common.m b/net/vmnet-common.m
> > index 30c4e53c13..bce1cc590d 100644
> > --- a/net/vmnet-common.m
> > +++ b/net/vmnet-common.m
> > @@ -18,6 +18,7 @@
> >  #include "qemu/error-report.h"
> >  #include "qapi/error.h"
> >  #include "sysemu/runstate.h"
> > +#include "net/eth.h"
> >
> >  #include <vmnet/vmnet.h>
> >  #include <dispatch/dispatch.h>
> > @@ -147,10 +148,25 @@ static int vmnet_read_packets(VmnetState *s)
> >   */
> >  static void vmnet_write_packets_to_qemu(VmnetState *s)
> >  {
> > +    uint8_t *pkt;
> > +    size_t pktsz;
> > +    uint8_t min_pkt[ETH_ZLEN];
> > +    size_t min_pktsz;
> > +
> >      while (s->packets_send_current_pos < s->packets_send_end_pos) {
> > -        ssize_t size = qemu_send_packet_async(&s->nc,
> > -                                      s->iov_buf[s->packets_send_current_pos].iov_base,
> > -                                      s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
> > +        pkt = s->iov_buf[s->packets_send_current_pos].iov_base;
> > +        pktsz = s->packets_buf[s->packets_send_current_pos].vm_pkt_size;
> > +
> > +        if (net_peer_needs_padding(&s->nc)) {
> > +            min_pktsz = sizeof(min_pkt);
> > +
> > +            if (eth_pad_short_frame(min_pkt, &min_pktsz, pkt, pktsz)) {
> > +                pkt = min_pkt;
> > +                pktsz = min_pktsz;
> > +            }
> > +        }
> > +
> > +        ssize_t size = qemu_send_packet_async(&s->nc, pkt, pktsz,
> >                                        vmnet_send_completed);

Nit: Move the declaration of 'size' up to the function header with the
rest of the variables for consistency.

Apart from that:
Reviewed-by: Phil Dennis-Jordan <phil@philjordan.eu>


> >          if (size == 0) {
> > --
> > 2.37.1
>
> Ping?
>
[PATCH v3] net/vmnet: Pad short Ethernet frames
Posted by William Hooper 3 weeks ago 
At least on macOS 12.7.2, vmnet doesn't pad Ethernet frames, such as the
host's ARP replies, to the minimum size (60 bytes before the frame check
sequence) defined in IEEE Std 802.3-2022, so guests' Ethernet device
drivers may drop them with "frame too short" errors.

This patch calls eth_pad_short_frame() to add padding, as in net/tap.c
and net/slirp.c. Thanks to Bin Meng, Philippe Mathieu-Daudé, and Phil
Dennis-Jordan for reviewing earlier versions.

Signed-off-by: William Hooper <wsh@wshooper.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2058
Reviewed-by: Phil Dennis-Jordan <phil@philjordan.eu>
---
 net/vmnet-common.m | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/net/vmnet-common.m b/net/vmnet-common.m
index 30c4e53c13..4b7e330c05 100644
--- a/net/vmnet-common.m
+++ b/net/vmnet-common.m
@@ -18,6 +18,7 @@
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "sysemu/runstate.h"
+#include "net/eth.h"
 
 #include <vmnet/vmnet.h>
 #include <dispatch/dispatch.h>
@@ -147,10 +148,26 @@ static int vmnet_read_packets(VmnetState *s)
  */
 static void vmnet_write_packets_to_qemu(VmnetState *s)
 {
+    uint8_t *pkt;
+    size_t pktsz;
+    uint8_t min_pkt[ETH_ZLEN];
+    size_t min_pktsz;
+    ssize_t size;
+
     while (s->packets_send_current_pos < s->packets_send_end_pos) {
-        ssize_t size = qemu_send_packet_async(&s->nc,
-                                      s->iov_buf[s->packets_send_current_pos].iov_base,
-                                      s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
+        pkt = s->iov_buf[s->packets_send_current_pos].iov_base;
+        pktsz = s->packets_buf[s->packets_send_current_pos].vm_pkt_size;
+
+        if (net_peer_needs_padding(&s->nc)) {
+            min_pktsz = sizeof(min_pkt);
+
+            if (eth_pad_short_frame(min_pkt, &min_pktsz, pkt, pktsz)) {
+                pkt = min_pkt;
+                pktsz = min_pktsz;
+            }
+        }
+
+        size = qemu_send_packet_async(&s->nc, pkt, pktsz,
                                       vmnet_send_completed);
 
         if (size == 0) {
Ping: [PATCH v3] net/vmnet: Pad short Ethernet frames
Posted by William Hooper 1 week ago 
On Sat, Nov 2, 2024 at 1:56 PM William Hooper <wsh@wshooper.org> wrote:
> At least on macOS 12.7.2, vmnet doesn't pad Ethernet frames, such as the
> host's ARP replies, to the minimum size (60 bytes before the frame check
> sequence) defined in IEEE Std 802.3-2022, so guests' Ethernet device
> drivers may drop them with "frame too short" errors.
>
> This patch calls eth_pad_short_frame() to add padding, as in net/tap.c
> and net/slirp.c. Thanks to Bin Meng, Philippe Mathieu-Daudé, and Phil
> Dennis-Jordan for reviewing earlier versions.
>
> Signed-off-by: William Hooper <wsh@wshooper.org>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2058
> Reviewed-by: Phil Dennis-Jordan <phil@philjordan.eu>
> ---
>  net/vmnet-common.m | 23 ++++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/net/vmnet-common.m b/net/vmnet-common.m
> index 30c4e53c13..4b7e330c05 100644
> --- a/net/vmnet-common.m
> +++ b/net/vmnet-common.m
> @@ -18,6 +18,7 @@
>  #include "qemu/error-report.h"
>  #include "qapi/error.h"
>  #include "sysemu/runstate.h"
> +#include "net/eth.h"
>
>  #include <vmnet/vmnet.h>
>  #include <dispatch/dispatch.h>
> @@ -147,10 +148,26 @@ static int vmnet_read_packets(VmnetState *s)
>   */
>  static void vmnet_write_packets_to_qemu(VmnetState *s)
>  {
> +    uint8_t *pkt;
> +    size_t pktsz;
> +    uint8_t min_pkt[ETH_ZLEN];
> +    size_t min_pktsz;
> +    ssize_t size;
> +
>      while (s->packets_send_current_pos < s->packets_send_end_pos) {
> -        ssize_t size = qemu_send_packet_async(&s->nc,
> -                                      s->iov_buf[s->packets_send_current_pos].iov_base,
> -                                      s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
> +        pkt = s->iov_buf[s->packets_send_current_pos].iov_base;
> +        pktsz = s->packets_buf[s->packets_send_current_pos].vm_pkt_size;
> +
> +        if (net_peer_needs_padding(&s->nc)) {
> +            min_pktsz = sizeof(min_pkt);
> +
> +            if (eth_pad_short_frame(min_pkt, &min_pktsz, pkt, pktsz)) {
> +                pkt = min_pkt;
> +                pktsz = min_pktsz;
> +            }
> +        }
> +
> +        size = qemu_send_packet_async(&s->nc, pkt, pktsz,
>                                        vmnet_send_completed);
>
>          if (size == 0) {

Ping?

https://patchew.org/QEMU/20241102205653.30476-1-wsh@wshooper.org/

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