On 16-03-04 07:11 AM, Phil Sutter wrote:
Cc: Gregoire Baron <baronc...@n7mm.org>
Signed-off-by: Phil Sutter <p...@nwl.cc>
---
man/man8/tc-csum.8 | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)
create mode 100644 man/man8/tc-csum.8
diff --git a/man/man8/tc-csum.8 b/man/man8/tc-csum.8
new file mode 100644
index 0000000000000..9d00aae346af0
--- /dev/null
+++ b/man/man8/tc-csum.8
@@ -0,0 +1,54 @@
+.TH "Checksum action in tc" 8 "11 Jan 2015" "iproute2" "Linux"
+
+.SH NAME
+csum - checksum update action
+.SH SYNOPSIS
+.in +8
+.ti -8
+.BR tc " ... " "action csum"
+.I UPDATE
+
+.ti -8
+.IR UPDATE " := " TARGET " [ " UPDATE " ]"
+
+.ti -8
+.IR TARGET " := { "
+.BR ip4h " |"
+.BR icmp " |"
+.BR igmp " |"
+.BR tcp " |"
+.BR udp " |"
+.BR udplite " |"
+.IR SWEETS " }"
+
+.ti -8
+.IR SWEETS " := { "
+.BR and " | " or " | " + " }"
+.SH DESCRIPTION
+The
+.B csum
+action triggers checksum recalculation of specified packet headers. It is
+commonly used after packet editing using the
+.B pedit
+action to fix for then incorrect checksums.
Would it make sense to add an example? From the commit log:
---
# In order to DNAT (stateless) IPv4 packet from 192.168.1.100 to
# 0x12345678 (18.52.86.120), and update the IPv4 header checksum and
# the UDP checksum (the last one, only if the packet is UDP).
tc filter add eth0 prio 1 protocol ip parent ffff: \
u32 match ip src 192.168.1.100/32 flowid :1 \
action pedit munge offset 16 u32 set 0x12345678 \
pipe csum ip and udp
# In order to alter destination address of IPv6 TCP packets from
fc00::1
# and correct the TCP checksum (nothing happened? except maybe for
# checksums in the TCP payload ...).
tc filter add eth0 prio 1 protocol ipv6 parent ffff: \
u32 match ip6 src fc00::1/128 match ip6 protocol 0x06 0xff flowid
:1 \
action pedit munge offset 24 u32 set 0x12345678 \
pipe csum tcp
-----
cheers,
jamal
