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authorBen Greear <greearb@candelatech.com>2011-02-11 09:35:18 +0000
committerDavid S. Miller <davem@davemloft.net>2011-02-11 21:26:32 -0800
commit57f89bfa21403d902ee176ef988136b75d9ab30b (patch)
tree3ebee83312498997fdd4630acfe0cfccec84835c /net/packet
parentab889e6607f6e3d52a76c5a43c8c4ad1d354da36 (diff)
network: Allow af_packet to transmit +4 bytes for VLAN packets.
This allows user-space to send a '1500' MTU VLAN packet on a 1500 MTU ethernet frame. The extra 4 bytes of a VLAN header is not usually charged against the MTU when other parts of the network stack is transmitting vlans... Signed-off-by: Ben Greear <greearb@candelatech.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c31
1 files changed, 29 insertions, 2 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index c60649ec1193..5efef5b5879e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -465,7 +465,7 @@ retry:
*/
err = -EMSGSIZE;
- if (len > dev->mtu + dev->hard_header_len)
+ if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN)
goto out_unlock;
if (!skb) {
@@ -496,6 +496,19 @@ retry:
goto retry;
}
+ if (len > (dev->mtu + dev->hard_header_len)) {
+ /* Earlier code assumed this would be a VLAN pkt,
+ * double-check this now that we have the actual
+ * packet in hand.
+ */
+ struct ethhdr *ehdr;
+ skb_reset_mac_header(skb);
+ ehdr = eth_hdr(skb);
+ if (ehdr->h_proto != htons(ETH_P_8021Q)) {
+ err = -EMSGSIZE;
+ goto out_unlock;
+ }
+ }
skb->protocol = proto;
skb->dev = dev;
@@ -1199,7 +1212,7 @@ static int packet_snd(struct socket *sock,
}
err = -EMSGSIZE;
- if (!gso_type && (len > dev->mtu+reserve))
+ if (!gso_type && (len > dev->mtu + reserve + VLAN_HLEN))
goto out_unlock;
err = -ENOBUFS;
@@ -1224,6 +1237,20 @@ static int packet_snd(struct socket *sock,
if (err < 0)
goto out_free;
+ if (!gso_type && (len > dev->mtu + reserve)) {
+ /* Earlier code assumed this would be a VLAN pkt,
+ * double-check this now that we have the actual
+ * packet in hand.
+ */
+ struct ethhdr *ehdr;
+ skb_reset_mac_header(skb);
+ ehdr = eth_hdr(skb);
+ if (ehdr->h_proto != htons(ETH_P_8021Q)) {
+ err = -EMSGSIZE;
+ goto out_free;
+ }
+ }
+
skb->protocol = proto;
skb->dev = dev;
skb->priority = sk->sk_priority;