Commit cbd89acb authored by Phil Sutter's avatar Phil Sutter Committed by David S. Miller
Browse files

af_packet: fix for sending VLAN frames via packet_mmap 



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: default avatarPhil Sutter <phil@nwl.cc>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0f75b09c

net/packet/af_packet.c

+14 −11
Original line number Diff line number Diff line
@@ -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);

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