Provided by: systemtap-doc_2.3-1ubuntu1.4_all 

NAME
probe::netfilter.ip.forward - Called on an incoming IP packet addressed to some other computer
SYNOPSIS
netfilter.ip.forward
VALUES
length
The length of the packet buffer contents, in bytes
fin
TCP FIN flag (if protocol is TCP; ipv4 only)
nf_repeat
Constant used to signify a 'repeat' verdict
ipproto_tcp
Constant used to signify that the packet protocol is TCP
ack
TCP ACK flag (if protocol is TCP; ipv4 only)
ipproto_udp
Constant used to signify that the packet protocol is UDP
rst
TCP RST flag (if protocol is TCP; ipv4 only)
iphdr
Address of IP header
indev_name
Name of network device packet was received on (if known)
dport
TCP or UDP destination port (ipv4 only)
syn
TCP SYN flag (if protocol is TCP; ipv4 only)
psh
TCP PSH flag (if protocol is TCP; ipv4 only)
nf_accept
Constant used to signify an 'accept' verdict
sport
TCP or UDP source port (ipv4 only)
saddr
A string representing the source IP address
nf_stop
Constant used to signify a 'stop' verdict
pf
Protocol family -- either “ipv4” or “ipv6”
daddr
A string representing the destination IP address
nf_drop
Constant used to signify a 'drop' verdict
nf_queue
Constant used to signify a 'queue' verdict
indev
Address of net_device representing input device, 0 if unknown
family
IP address family
urg
TCP URG flag (if protocol is TCP; ipv4 only)
protocol
Packet protocol from driver (ipv4 only)
outdev_name
Name of network device packet will be routed to (if known)
nf_stolen
Constant used to signify a 'stolen' verdict
outdev
Address of net_device representing output device, 0 if unknown
SystemTap Tapset Reference March 2016 PROBE::NETFILTER.I(3stap)