@@ -1924,7 +1924,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
__be16 proto, unsigned char *addr, int hlen)
{
union tpacket_uhdr ph;
- int to_write, offset, len, tp_len, nr_frags, len_max;
+ int to_write, offset, len, tp_len, nr_frags, len_max, max_frame_len;
struct socket *sock = po->sk.sk_socket;
struct page *page;
void *data;
@@ -1947,10 +1947,6 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
tp_len = ph.h1->tp_len;
break;
}
- if (unlikely(tp_len > size_max)) {
- pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
- return -EMSGSIZE;
- }
skb_reserve(skb, hlen);
skb_reset_network_header(skb);
@@ -2013,6 +2009,18 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
to_write -= dev->hard_header_len;
}
+ max_frame_len = dev->mtu + dev->hard_header_len;
+ if (skb->protocol == htons(ETH_P_8021Q))
+ max_frame_len += VLAN_HLEN;
+
+ if (size_max > max_frame_len)
+ size_max = max_frame_len;
+
+ if (unlikely(tp_len > size_max)) {
+ pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
+ return -EMSGSIZE;
+ }
+
offset = offset_in_page(data);
len_max = PAGE_SIZE - offset;
len = ((to_write > len_max) ? len_max : to_write);
@@ -2051,7 +2059,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
struct net_device *dev;
__be16 proto;
bool need_rls_dev = false;
- int err, reserve = 0;
+ int err;
void *ph;
struct sockaddr_ll *saddr = (struct sockaddr_ll *)msg->msg_name;
int tp_len, size_max;
@@ -2084,8 +2092,6 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
if (unlikely(dev == NULL))
goto out;
- reserve = dev->hard_header_len;
-
err = -ENETDOWN;
if (unlikely(!(dev->flags & IFF_UP)))
goto out_put;
@@ -2093,9 +2099,6 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
size_max = po->tx_ring.frame_size
- (po->tp_hdrlen - sizeof(struct sockaddr_ll));
- if (size_max > dev->mtu + reserve)
- size_max = dev->mtu + reserve;
-
do {
ph = packet_current_frame(po, &po->tx_ring,
TP_STATUS_SEND_REQUEST);
Since tpacket_fill_skb() parses the protocol field in ethernet frames' headers, it's easy to see if any passed frame is a VLAN one and account for the extended size. But as the real protocol does not turn up before tpacket_fill_skb() runs which in turn also checks the frame length, move the max frame length calculation into the function. Signed-off-by: Phil Sutter <phil@nwl.cc> --- net/packet/af_packet.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-)