[PATCH] net: Strip virtio-net header when dumping

Akihiko Odaki posted 1 patch 1 year, 3 months ago
There is a newer version of this series
include/net/net.h |  6 ++++++
net/dump.c        | 11 +++++++----
net/net.c         | 18 ++++++++++++++++++
net/netmap.c      |  1 +
net/tap.c         | 16 ++++++++++++++++
5 files changed, 48 insertions(+), 4 deletions(-)
[PATCH] net: Strip virtio-net header when dumping
Posted by Akihiko Odaki 1 year, 3 months ago
filter-dump specifiees Ethernet as PCAP LinkType, which does not expect
virtio-net header. Having virtio-net header in such PCAP file breaks
PCAP unconsumable. Unfortunately currently there is no LinkType for
virtio-net so for now strip virtio-net header to convert the output to
Ethernet.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 include/net/net.h |  6 ++++++
 net/dump.c        | 11 +++++++----
 net/net.c         | 18 ++++++++++++++++++
 net/netmap.c      |  1 +
 net/tap.c         | 16 ++++++++++++++++
 5 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/include/net/net.h b/include/net/net.h
index dc20b31e9f..4b2d72b3fc 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -56,8 +56,10 @@ typedef RxFilterInfo *(QueryRxFilter)(NetClientState *);
 typedef bool (HasUfo)(NetClientState *);
 typedef bool (HasVnetHdr)(NetClientState *);
 typedef bool (HasVnetHdrLen)(NetClientState *, int);
+typedef bool (GetUsingVnetHdr)(NetClientState *);
 typedef void (UsingVnetHdr)(NetClientState *, bool);
 typedef void (SetOffload)(NetClientState *, int, int, int, int, int);
+typedef int (GetVnetHdrLen)(NetClientState *);
 typedef void (SetVnetHdrLen)(NetClientState *, int);
 typedef int (SetVnetLE)(NetClientState *, bool);
 typedef int (SetVnetBE)(NetClientState *, bool);
@@ -84,8 +86,10 @@ typedef struct NetClientInfo {
     HasUfo *has_ufo;
     HasVnetHdr *has_vnet_hdr;
     HasVnetHdrLen *has_vnet_hdr_len;
+    GetUsingVnetHdr *get_using_vnet_hdr;
     UsingVnetHdr *using_vnet_hdr;
     SetOffload *set_offload;
+    GetVnetHdrLen *get_vnet_hdr_len;
     SetVnetHdrLen *set_vnet_hdr_len;
     SetVnetLE *set_vnet_le;
     SetVnetBE *set_vnet_be;
@@ -183,9 +187,11 @@ void qemu_format_nic_info_str(NetClientState *nc, uint8_t macaddr[6]);
 bool qemu_has_ufo(NetClientState *nc);
 bool qemu_has_vnet_hdr(NetClientState *nc);
 bool qemu_has_vnet_hdr_len(NetClientState *nc, int len);
+bool qemu_get_using_vnet_hdr(NetClientState *nc);
 void qemu_using_vnet_hdr(NetClientState *nc, bool enable);
 void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
                       int ecn, int ufo);
+int qemu_get_vnet_hdr_len(NetClientState *nc);
 void qemu_set_vnet_hdr_len(NetClientState *nc, int len);
 int qemu_set_vnet_le(NetClientState *nc, bool is_le);
 int qemu_set_vnet_be(NetClientState *nc, bool is_be);
diff --git a/net/dump.c b/net/dump.c
index 6a63b15359..7d05f16ca7 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -61,12 +61,13 @@ struct pcap_sf_pkthdr {
     uint32_t len;
 };
 
-static ssize_t dump_receive_iov(DumpState *s, const struct iovec *iov, int cnt)
+static ssize_t dump_receive_iov(DumpState *s, const struct iovec *iov, int cnt,
+                                int offset)
 {
     struct pcap_sf_pkthdr hdr;
     int64_t ts;
     int caplen;
-    size_t size = iov_size(iov, cnt);
+    size_t size = iov_size(iov, cnt) - offset;
     struct iovec dumpiov[cnt + 1];
 
     /* Early return in case of previous error. */
@@ -84,7 +85,7 @@ static ssize_t dump_receive_iov(DumpState *s, const struct iovec *iov, int cnt)
 
     dumpiov[0].iov_base = &hdr;
     dumpiov[0].iov_len = sizeof(hdr);
-    cnt = iov_copy(&dumpiov[1], cnt, iov, cnt, 0, caplen);
+    cnt = iov_copy(&dumpiov[1], cnt, iov, cnt, offset, caplen);
 
     if (writev(s->fd, dumpiov, cnt + 1) != sizeof(hdr) + caplen) {
         error_report("network dump write error - stopping dump");
@@ -153,8 +154,10 @@ static ssize_t filter_dump_receive_iov(NetFilterState *nf, NetClientState *sndr,
                                        int iovcnt, NetPacketSent *sent_cb)
 {
     NetFilterDumpState *nfds = FILTER_DUMP(nf);
+    int offset = qemu_get_using_vnet_hdr(nf->netdev) ?
+                 qemu_get_vnet_hdr_len(nf->netdev) : 0;
 
-    dump_receive_iov(&nfds->ds, iov, iovcnt);
+    dump_receive_iov(&nfds->ds, iov, iovcnt, offset);
     return 0;
 }
 
diff --git a/net/net.c b/net/net.c
index 2d01472998..3a95c3ba6a 100644
--- a/net/net.c
+++ b/net/net.c
@@ -513,6 +513,15 @@ bool qemu_has_vnet_hdr_len(NetClientState *nc, int len)
     return nc->info->has_vnet_hdr_len(nc, len);
 }
 
+bool qemu_get_using_vnet_hdr(NetClientState *nc)
+{
+    if (!nc || !nc->info->get_using_vnet_hdr) {
+        return false;
+    }
+
+    return nc->info->get_using_vnet_hdr(nc);
+}
+
 void qemu_using_vnet_hdr(NetClientState *nc, bool enable)
 {
     if (!nc || !nc->info->using_vnet_hdr) {
@@ -532,6 +541,15 @@ void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
     nc->info->set_offload(nc, csum, tso4, tso6, ecn, ufo);
 }
 
+int qemu_get_vnet_hdr_len(NetClientState *nc)
+{
+    if (!nc || !nc->info->get_vnet_hdr_len) {
+        return -ENOSYS;
+    }
+
+    return nc->info->get_vnet_hdr_len(nc);
+}
+
 void qemu_set_vnet_hdr_len(NetClientState *nc, int len)
 {
     if (!nc || !nc->info->set_vnet_hdr_len) {
diff --git a/net/netmap.c b/net/netmap.c
index 9e0cec58d3..ed9c7ec948 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -393,6 +393,7 @@ static NetClientInfo net_netmap_info = {
     .has_ufo = netmap_has_vnet_hdr,
     .has_vnet_hdr = netmap_has_vnet_hdr,
     .has_vnet_hdr_len = netmap_has_vnet_hdr_len,
+    .get_using_vnet_hdr = netmap_get_using_vnet_hdr,
     .using_vnet_hdr = netmap_using_vnet_hdr,
     .set_offload = netmap_set_offload,
     .set_vnet_hdr_len = netmap_set_vnet_hdr_len,
diff --git a/net/tap.c b/net/tap.c
index e28ceb078f..daa7e0a042 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -257,6 +257,13 @@ static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
     return !!tap_probe_vnet_hdr_len(s->fd, len);
 }
 
+static int tap_get_vnet_hdr_len(NetClientState *nc)
+{
+    TAPState *s = DO_UPCAST(TAPState, nc, nc);
+
+    return s->host_vnet_hdr_len;
+}
+
 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
@@ -270,6 +277,13 @@ static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
     s->host_vnet_hdr_len = len;
 }
 
+static bool tap_get_using_vnet_hdr(NetClientState *nc)
+{
+    TAPState *s = DO_UPCAST(TAPState, nc, nc);
+
+    return s->using_vnet_hdr;
+}
+
 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
@@ -374,8 +388,10 @@ static NetClientInfo net_tap_info = {
     .has_ufo = tap_has_ufo,
     .has_vnet_hdr = tap_has_vnet_hdr,
     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
+    .get_using_vnet_hdr = tap_get_using_vnet_hdr,
     .using_vnet_hdr = tap_using_vnet_hdr,
     .set_offload = tap_set_offload,
+    .get_vnet_hdr_len = tap_get_vnet_hdr_len,
     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
     .set_vnet_le = tap_set_vnet_le,
     .set_vnet_be = tap_set_vnet_be,
-- 
2.39.0
Re: [PATCH] net: Strip virtio-net header when dumping
Posted by Philippe Mathieu-Daudé 1 year, 3 months ago
On 13/1/23 14:08, Akihiko Odaki wrote:
> filter-dump specifiees Ethernet as PCAP LinkType, which does not expect
> virtio-net header. Having virtio-net header in such PCAP file breaks
> PCAP unconsumable. Unfortunately currently there is no LinkType for
> virtio-net so for now strip virtio-net header to convert the output to
> Ethernet.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>   include/net/net.h |  6 ++++++
>   net/dump.c        | 11 +++++++----
>   net/net.c         | 18 ++++++++++++++++++
>   net/netmap.c      |  1 +
>   net/tap.c         | 16 ++++++++++++++++
>   5 files changed, 48 insertions(+), 4 deletions(-)
> 
> diff --git a/include/net/net.h b/include/net/net.h
> index dc20b31e9f..4b2d72b3fc 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -56,8 +56,10 @@ typedef RxFilterInfo *(QueryRxFilter)(NetClientState *);
>   typedef bool (HasUfo)(NetClientState *);
>   typedef bool (HasVnetHdr)(NetClientState *);
>   typedef bool (HasVnetHdrLen)(NetClientState *, int);
> +typedef bool (GetUsingVnetHdr)(NetClientState *);
>   typedef void (UsingVnetHdr)(NetClientState *, bool);
>   typedef void (SetOffload)(NetClientState *, int, int, int, int, int);
> +typedef int (GetVnetHdrLen)(NetClientState *);
>   typedef void (SetVnetHdrLen)(NetClientState *, int);
>   typedef int (SetVnetLE)(NetClientState *, bool);
>   typedef int (SetVnetBE)(NetClientState *, bool);
> @@ -84,8 +86,10 @@ typedef struct NetClientInfo {
>       HasUfo *has_ufo;
>       HasVnetHdr *has_vnet_hdr;
>       HasVnetHdrLen *has_vnet_hdr_len;
> +    GetUsingVnetHdr *get_using_vnet_hdr;

[*]

>       UsingVnetHdr *using_vnet_hdr;
>       SetOffload *set_offload;
> +    GetVnetHdrLen *get_vnet_hdr_len;
>       SetVnetHdrLen *set_vnet_hdr_len;
>       SetVnetLE *set_vnet_le;
>       SetVnetBE *set_vnet_be;
> @@ -183,9 +187,11 @@ void qemu_format_nic_info_str(NetClientState *nc, uint8_t macaddr[6]);
>   bool qemu_has_ufo(NetClientState *nc);
>   bool qemu_has_vnet_hdr(NetClientState *nc);
>   bool qemu_has_vnet_hdr_len(NetClientState *nc, int len);
> +bool qemu_get_using_vnet_hdr(NetClientState *nc);
>   void qemu_using_vnet_hdr(NetClientState *nc, bool enable);
>   void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
>                         int ecn, int ufo);

> @@ -153,8 +154,10 @@ static ssize_t filter_dump_receive_iov(NetFilterState *nf, NetClientState *sndr,
>                                          int iovcnt, NetPacketSent *sent_cb)
>   {
>       NetFilterDumpState *nfds = FILTER_DUMP(nf);
> +    int offset = qemu_get_using_vnet_hdr(nf->netdev) ?
> +                 qemu_get_vnet_hdr_len(nf->netdev) : 0;
>   
> -    dump_receive_iov(&nfds->ds, iov, iovcnt);
> +    dump_receive_iov(&nfds->ds, iov, iovcnt, offset);
>       return 0;
>   }
>   
> diff --git a/net/net.c b/net/net.c
> index 2d01472998..3a95c3ba6a 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -513,6 +513,15 @@ bool qemu_has_vnet_hdr_len(NetClientState *nc, int len)
>       return nc->info->has_vnet_hdr_len(nc, len);
>   }
>   
> +bool qemu_get_using_vnet_hdr(NetClientState *nc)
> +{
> +    if (!nc || !nc->info->get_using_vnet_hdr) {
> +        return false;
> +    }
> +
> +    return nc->info->get_using_vnet_hdr(nc);

Per [*], is get_using_vnet_hdr() really useful? Can't we just
check for using_vnet_hdr != NULL as:

        return nc->info->using_vnet_hdr != NULL;

> +}
> +
>   void qemu_using_vnet_hdr(NetClientState *nc, bool enable)
>   {
>       if (!nc || !nc->info->using_vnet_hdr) {
> @@ -532,6 +541,15 @@ void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
>       nc->info->set_offload(nc, csum, tso4, tso6, ecn, ufo);
>   }
>   
> +int qemu_get_vnet_hdr_len(NetClientState *nc)
> +{
> +    if (!nc || !nc->info->get_vnet_hdr_len) {
> +        return -ENOSYS;

Does -ENOSYS provides any value? Otherwise we could return 0.

> +    }
> +
> +    return nc->info->get_vnet_hdr_len(nc);
> +}

> diff --git a/net/netmap.c b/net/netmap.c
> index 9e0cec58d3..ed9c7ec948 100644
> --- a/net/netmap.c
> +++ b/net/netmap.c
> @@ -393,6 +393,7 @@ static NetClientInfo net_netmap_info = {
>       .has_ufo = netmap_has_vnet_hdr,
>       .has_vnet_hdr = netmap_has_vnet_hdr,
>       .has_vnet_hdr_len = netmap_has_vnet_hdr_len,
> +    .get_using_vnet_hdr = netmap_get_using_vnet_hdr,

On what is this patch based? I don't have netmap_get_using_vnet_hdr().

>       .using_vnet_hdr = netmap_using_vnet_hdr,
>       .set_offload = netmap_set_offload,
>       .set_vnet_hdr_len = netmap_set_vnet_hdr_len,
Re: [PATCH] net: Strip virtio-net header when dumping
Posted by Akihiko Odaki 1 year, 3 months ago
On 2023/01/13 22:40, Philippe Mathieu-Daudé wrote:
> On 13/1/23 14:08, Akihiko Odaki wrote:
>> filter-dump specifiees Ethernet as PCAP LinkType, which does not expect
>> virtio-net header. Having virtio-net header in such PCAP file breaks
>> PCAP unconsumable. Unfortunately currently there is no LinkType for
>> virtio-net so for now strip virtio-net header to convert the output to
>> Ethernet.
>>
>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
>> ---
>>   include/net/net.h |  6 ++++++
>>   net/dump.c        | 11 +++++++----
>>   net/net.c         | 18 ++++++++++++++++++
>>   net/netmap.c      |  1 +
>>   net/tap.c         | 16 ++++++++++++++++
>>   5 files changed, 48 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/net/net.h b/include/net/net.h
>> index dc20b31e9f..4b2d72b3fc 100644
>> --- a/include/net/net.h
>> +++ b/include/net/net.h
>> @@ -56,8 +56,10 @@ typedef RxFilterInfo 
>> *(QueryRxFilter)(NetClientState *);
>>   typedef bool (HasUfo)(NetClientState *);
>>   typedef bool (HasVnetHdr)(NetClientState *);
>>   typedef bool (HasVnetHdrLen)(NetClientState *, int);
>> +typedef bool (GetUsingVnetHdr)(NetClientState *);
>>   typedef void (UsingVnetHdr)(NetClientState *, bool);
>>   typedef void (SetOffload)(NetClientState *, int, int, int, int, int);
>> +typedef int (GetVnetHdrLen)(NetClientState *);
>>   typedef void (SetVnetHdrLen)(NetClientState *, int);
>>   typedef int (SetVnetLE)(NetClientState *, bool);
>>   typedef int (SetVnetBE)(NetClientState *, bool);
>> @@ -84,8 +86,10 @@ typedef struct NetClientInfo {
>>       HasUfo *has_ufo;
>>       HasVnetHdr *has_vnet_hdr;
>>       HasVnetHdrLen *has_vnet_hdr_len;
>> +    GetUsingVnetHdr *get_using_vnet_hdr;
> 
> [*]
> 
>>       UsingVnetHdr *using_vnet_hdr;
>>       SetOffload *set_offload;
>> +    GetVnetHdrLen *get_vnet_hdr_len;
>>       SetVnetHdrLen *set_vnet_hdr_len;
>>       SetVnetLE *set_vnet_le;
>>       SetVnetBE *set_vnet_be;
>> @@ -183,9 +187,11 @@ void qemu_format_nic_info_str(NetClientState *nc, 
>> uint8_t macaddr[6]);
>>   bool qemu_has_ufo(NetClientState *nc);
>>   bool qemu_has_vnet_hdr(NetClientState *nc);
>>   bool qemu_has_vnet_hdr_len(NetClientState *nc, int len);
>> +bool qemu_get_using_vnet_hdr(NetClientState *nc);
>>   void qemu_using_vnet_hdr(NetClientState *nc, bool enable);
>>   void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
>>                         int ecn, int ufo);
> 
>> @@ -153,8 +154,10 @@ static ssize_t 
>> filter_dump_receive_iov(NetFilterState *nf, NetClientState *sndr,
>>                                          int iovcnt, NetPacketSent 
>> *sent_cb)
>>   {
>>       NetFilterDumpState *nfds = FILTER_DUMP(nf);
>> +    int offset = qemu_get_using_vnet_hdr(nf->netdev) ?
>> +                 qemu_get_vnet_hdr_len(nf->netdev) : 0;
>> -    dump_receive_iov(&nfds->ds, iov, iovcnt);
>> +    dump_receive_iov(&nfds->ds, iov, iovcnt, offset);
>>       return 0;
>>   }
>> diff --git a/net/net.c b/net/net.c
>> index 2d01472998..3a95c3ba6a 100644
>> --- a/net/net.c
>> +++ b/net/net.c
>> @@ -513,6 +513,15 @@ bool qemu_has_vnet_hdr_len(NetClientState *nc, 
>> int len)
>>       return nc->info->has_vnet_hdr_len(nc, len);
>>   }
>> +bool qemu_get_using_vnet_hdr(NetClientState *nc)
>> +{
>> +    if (!nc || !nc->info->get_using_vnet_hdr) {
>> +        return false;
>> +    }
>> +
>> +    return nc->info->get_using_vnet_hdr(nc);
> 
> Per [*], is get_using_vnet_hdr() really useful? Can't we just
> check for using_vnet_hdr != NULL as:

tap allows to disable vnet_hdr by passing false to using_vnet_hdr() so 
we need to ask it whether vnet_hdr is currently enabled or not.

> 
>         return nc->info->using_vnet_hdr != NULL;
> 
>> +}
>> +
>>   void qemu_using_vnet_hdr(NetClientState *nc, bool enable)
>>   {
>>       if (!nc || !nc->info->using_vnet_hdr) {
>> @@ -532,6 +541,15 @@ void qemu_set_offload(NetClientState *nc, int 
>> csum, int tso4, int tso6,
>>       nc->info->set_offload(nc, csum, tso4, tso6, ecn, ufo);
>>   }
>> +int qemu_get_vnet_hdr_len(NetClientState *nc)
>> +{
>> +    if (!nc || !nc->info->get_vnet_hdr_len) {
>> +        return -ENOSYS;
> 
> Does -ENOSYS provides any value? Otherwise we could return 0.

I have just sent v2, which returns 0 here instead. tap returns 0 in case 
vnet_hdr is disabled so this should also return 0.

> 
>> +    }
>> +
>> +    return nc->info->get_vnet_hdr_len(nc);
>> +}
> 
>> diff --git a/net/netmap.c b/net/netmap.c
>> index 9e0cec58d3..ed9c7ec948 100644
>> --- a/net/netmap.c
>> +++ b/net/netmap.c
>> @@ -393,6 +393,7 @@ static NetClientInfo net_netmap_info = {
>>       .has_ufo = netmap_has_vnet_hdr,
>>       .has_vnet_hdr = netmap_has_vnet_hdr,
>>       .has_vnet_hdr_len = netmap_has_vnet_hdr_len,
>> +    .get_using_vnet_hdr = netmap_get_using_vnet_hdr,
> 
> On what is this patch based? I don't have netmap_get_using_vnet_hdr().

This is a mistake; I removed it in v2.

Regards,
Akihiko Odaki

> 
>>       .using_vnet_hdr = netmap_using_vnet_hdr,
>>       .set_offload = netmap_set_offload,
>>       .set_vnet_hdr_len = netmap_set_vnet_hdr_len,
>