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 <redacted>
Cc: Willem de Bruijn <willemb@google.com>
---
Documentation/networking/packet_mmap.txt | 13 ++++++++++---
include/uapi/linux/if_packet.h | 1 +
net/packet/af_packet.c | 9 +++++++++
3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index a6d7cb9..daa015a 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -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 0diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
index da2d668..053bd10 100644
--- a/include/uapi/linux/if_packet.h
+++ b/include/uapi/linux/if_packet.h
@@ -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 0diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 6ecf8dd..3f09dda 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1918,6 +1918,10 @@ 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;
@@ -3015,6 +3019,11 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
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 = PACKET_SKB_CB(skb)->origlen;
aux.tp_snaplen = skb->len;
aux.tp_mac = 0;
--
1.9.1