Re: [Qemu-devel] [PATCH 1/5] eth: Extend vlan stripping functions

[Philippe Mathieu-Daudé]

On 02/16/2017 09:29 AM, Dmitry Fleytman wrote:

Make VLAN stripping functions return number of bytes
copied to given Ethernet header buffer.

This information should be used to re-compose
packet IOV after VLAN stripping.

Signed-off-by: Dmitry Fleytman <dmi...@daynix.com>
---
 include/net/eth.h |  4 ++--
 net/eth.c         | 25 ++++++++++++++-----------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/include/net/eth.h b/include/net/eth.h
index 2013175..afeb45b 100644
--- a/include/net/eth.h
+++ b/include/net/eth.h
@@ -331,12 +331,12 @@ eth_get_pkt_tci(const void *p)
     }
 }

-bool
+size_t
 eth_strip_vlan(const struct iovec *iov, int iovcnt, size_t iovoff,
                uint8_t *new_ehdr_buf,
                uint16_t *payload_offset, uint16_t *tci);

-bool
+size_t
 eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff,
                   uint16_t vet, uint8_t *new_ehdr_buf,
                   uint16_t *payload_offset, uint16_t *tci);
diff --git a/net/eth.c b/net/eth.c
index df81efb..5b9ba26 100644
--- a/net/eth.c
+++ b/net/eth.c
@@ -232,7 +232,7 @@ void eth_get_protocols(const struct iovec *iov, int iovcnt,
     }
 }

-bool
+size_t
 eth_strip_vlan(const struct iovec *iov, int iovcnt, size_t iovoff,
                uint8_t *new_ehdr_buf,
                uint16_t *payload_offset, uint16_t *tci)
@@ -244,7 +244,7 @@ eth_strip_vlan(const struct iovec *iov, int iovcnt, size_t 
iovoff,
                                new_ehdr, sizeof(*new_ehdr));

     if (copied < sizeof(*new_ehdr)) {
-        return false;
+        return 0;
     }

     switch (be16_to_cpu(new_ehdr->h_proto)) {
@@ -254,7 +254,7 @@ eth_strip_vlan(const struct iovec *iov, int iovcnt, size_t 
iovoff,
                             &vlan_hdr, sizeof(vlan_hdr));

         if (copied < sizeof(vlan_hdr)) {
-            return false;
+            return 0;
         }

         new_ehdr->h_proto = vlan_hdr.h_proto;
@@ -268,18 +268,21 @@ eth_strip_vlan(const struct iovec *iov, int iovcnt, 
size_t iovoff,
                                 PKT_GET_VLAN_HDR(new_ehdr), sizeof(vlan_hdr));

             if (copied < sizeof(vlan_hdr)) {
-                return false;
+                return 0;
             }

             *payload_offset += sizeof(vlan_hdr);
+
+            return sizeof(struct eth_header) + sizeof(struct vlan_header);
+        } else {
+            return sizeof(struct eth_header);

remove this "else return ..."

         }
-        return true;

here avoid fall-through with 'return sizeof(struct eth_header);'

     default:
-        return false;
+        return 0;
     }
 }

-bool
+size_t
 eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff,
                   uint16_t vet, uint8_t *new_ehdr_buf,
                   uint16_t *payload_offset, uint16_t *tci)
@@ -291,7 +294,7 @@ eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, 
size_t iovoff,
                                new_ehdr, sizeof(*new_ehdr));

     if (copied < sizeof(*new_ehdr)) {
-        return false;
+        return 0;
     }

     if (be16_to_cpu(new_ehdr->h_proto) == vet) {
@@ -299,17 +302,17 @@ eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, 
size_t iovoff,
                             &vlan_hdr, sizeof(vlan_hdr));

         if (copied < sizeof(vlan_hdr)) {
-            return false;
+            return 0;
         }

         new_ehdr->h_proto = vlan_hdr.h_proto;

         *tci = be16_to_cpu(vlan_hdr.h_tci);
         *payload_offset = iovoff + sizeof(*new_ehdr) + sizeof(vlan_hdr);
-        return true;
+        return sizeof(struct eth_header);
     }

-    return false;
+    return 0;
 }

 void

with changes:
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>

Phil.