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af_packet: pass checksum validation status to the user

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Introduce TP_STATUS_CSUM_VALID tp_status flag to tell the
af_packet user that at least the transport header checksum
has been already validated.

For now, the flag may be set for incoming packets only.

Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Drozdov 2015-03-23 09:11:13 +03:00 committed by David S. Miller
parent 68c2e5de36
commit 682f048bd4
3 changed files with 20 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

13
Documentation/networking/packet_mmap.txt
View file

@ -440,9 +440,10 @@ and the following flags apply:
+++ Capture process:
from include/linux/if_packet.h
#define TP_STATUS_COPY 2
#define TP_STATUS_LOSING 4
#define TP_STATUS_CSUMNOTREADY 8
#define TP_STATUS_COPY (1 << 1)
#define TP_STATUS_LOSING (1 << 2)
#define TP_STATUS_CSUMNOTREADY (1 << 3)
#define TP_STATUS_CSUM_VALID (1 << 7)
TP_STATUS_COPY : This flag indicates that the frame (and associated
meta information) has been truncated because it's
@ -466,6 +467,12 @@ TP_STATUS_CSUMNOTREADY: currently it's used for outgoing IP packets which
reading the packet we should not try to check the
checksum.
TP_STATUS_CSUM_VALID : This flag indicates that at least the transport
header checksum of the packet has been already
validated on the kernel side. If the flag is not set
then we are free to check the checksum by ourselves
provided that TP_STATUS_CSUMNOTREADY is also not set.
for convenience there are also the following defines:
#define TP_STATUS_KERNEL 0

1
include/uapi/linux/if_packet.h
View file

@ -99,6 +99,7 @@ struct tpacket_auxdata {
#define TP_STATUS_VLAN_VALID (1 << 4) /* auxdata has valid tp_vlan_tci */
#define TP_STATUS_BLK_TMO (1 << 5)
#define TP_STATUS_VLAN_TPID_VALID (1 << 6) /* auxdata has valid tp_vlan_tpid */
#define TP_STATUS_CSUM_VALID (1 << 7)
/* Tx ring - header status */
#define TP_STATUS_AVAILABLE 0

9
net/packet/af_packet.c
View file

@ -1924,6 +1924,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
if (skb->ip_summed == CHECKSUM_PARTIAL)
status |= TP_STATUS_CSUMNOTREADY;
else if (skb->pkt_type != PACKET_OUTGOING &&
(skb->ip_summed == CHECKSUM_COMPLETE ||
skb_csum_unnecessary(skb)))
status |= TP_STATUS_CSUM_VALID;
if (snaplen > res)
snaplen = res;
@ -3031,6 +3035,11 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
aux.tp_status = TP_STATUS_USER;
if (skb->ip_summed == CHECKSUM_PARTIAL)
aux.tp_status |= TP_STATUS_CSUMNOTREADY;
else if (skb->pkt_type != PACKET_OUTGOING &&
(skb->ip_summed == CHECKSUM_COMPLETE ||
skb_csum_unnecessary(skb)))
aux.tp_status |= TP_STATUS_CSUM_VALID;
aux.tp_len = origlen;
aux.tp_snaplen = skb->len;
aux.tp_mac = 0;