Commit c1aad275 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

packet: set transport header before doing xmit 



Set the transport header for 1) some drivers (e.g ixgbe needs l4 header to do
atr) 2) precise packet length estimation (introduced in 1def9238) needs l4
header to compute header length.

So this patch first tries to get l4 header for packet socket through
skb_flow_dissect(), and pretend no l4 header if skb_flow_dissect() fails.

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 38502af7

net/packet/af_packet.c

+21 −0
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ 
#include <linux/virtio_net.h>

#include <linux/errqueue.h>

#include <linux/net_tstamp.h>

#include <net/flow_keys.h>



#ifdef CONFIG_INET

#include <net/inet_common.h>
@@ -1412,6 +1413,7 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock, 
	__be16 proto = 0;

	int err;

	int extra_len = 0;

	struct flow_keys keys;



	/*

	 *	Get and verify the address.
@@ -1512,6 +1514,11 @@ retry: 
	if (unlikely(extra_len == 4))

		skb->no_fcs = 1;



	if (skb_flow_dissect(skb, &keys))

		skb_set_transport_header(skb, keys.thoff);

	else

		skb_reset_transport_header(skb);



	dev_queue_xmit(skb);

	rcu_read_unlock();

	return len;
@@ -1918,6 +1925,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, 
	struct page *page;

	void *data;

	int err;

	struct flow_keys keys;



	ph.raw = frame;
@@ -1943,6 +1951,11 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, 
	skb_reserve(skb, hlen);

	skb_reset_network_header(skb);



	if (skb_flow_dissect(skb, &keys))

		skb_set_transport_header(skb, keys.thoff);

	else

		skb_reset_transport_header(skb);



	if (po->tp_tx_has_off) {

		int off_min, off_max, off;

		off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
@@ -2199,6 +2212,7 @@ static int packet_snd(struct socket *sock, 
	unsigned short gso_type = 0;

	int hlen, tlen;

	int extra_len = 0;

	struct flow_keys keys;



	/*

	 *	Get and verify the address.
@@ -2351,6 +2365,13 @@ static int packet_snd(struct socket *sock, 
		len += vnet_hdr_len;

	}



	if (skb->ip_summed == CHECKSUM_PARTIAL)

		skb_set_transport_header(skb, skb_checksum_start_offset(skb));

	else if (skb_flow_dissect(skb, &keys))

		skb_set_transport_header(skb, keys.thoff);

	else

		skb_set_transport_header(skb, reserve);



	if (unlikely(extra_len == 4))

		skb->no_fcs = 1;

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