From cbd89acb9eb257ed3b2be867142583fdcf7fdc5b Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Fri, 2 Aug 2013 11:37:40 +0200 Subject: [PATCH] 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: Phil Sutter Signed-off-by: David S. Miller --- net/packet/af_packet.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 71db35ecba39..2b1470de9e16 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -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); -- 2.30.2