@@ -115,6 +115,7 @@ struct tpacket_auxdata {
#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)
+#define TP_STATUS_GSO_TCP (1 << 8)
/* Tx ring - header status */
#define TP_STATUS_AVAILABLE 0
@@ -2296,6 +2296,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
else if (skb->pkt_type != PACKET_OUTGOING &&
skb_csum_unnecessary(skb))
status |= TP_STATUS_CSUM_VALID;
+ if (skb_is_gso(skb) && skb_is_gso_tcp(skb))
+ status |= TP_STATUS_GSO_TCP;
if (snaplen > res)
snaplen = res;
@@ -3522,6 +3524,8 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
else if (skb->pkt_type != PACKET_OUTGOING &&
skb_csum_unnecessary(skb))
aux.tp_status |= TP_STATUS_CSUM_VALID;
+ if (skb_is_gso(skb) && skb_is_gso_tcp(skb))
+ aux.tp_status |= TP_STATUS_GSO_TCP;
aux.tp_len = origlen;
aux.tp_snaplen = skb->len;
Introduce TP_STATUS_GSO_TCP tp_status flag to tell the af_packet user that this is a TCP GSO packet. When parsing IPv4 BIG TCP packets in tcpdump/libpcap, it can use tp_len as the IPv4 packet len when this flag is set, as iph tot_len is set to 0 for IPv4 BIG TCP packets. Signed-off-by: Xin Long <lucien.xin@gmail.com> --- include/uapi/linux/if_packet.h | 1 + net/packet/af_packet.c | 4 ++++ 2 files changed, 5 insertions(+)