Daniel Borkmann 479ffcccef bpf: fix checksum fixups on bpf_skb_store_bytes ... bpf_skb_store_bytes() invocations above L2 header need BPF_F_RECOMPUTE_CSUM flag for updates, so that CHECKSUM_COMPLETE will be fixed up along the way. Where we ran into an issue with bpf_skb_store_bytes() is when we did a single-byte update on the IPv6 hoplimit despite using BPF_F_RECOMPUTE_CSUM flag; simple ping via ICMPv6 triggered a hw csum failure as a result. The underlying issue has been tracked down to a buffer alignment issue. Meaning, that csum_partial() computations via skb_postpull_rcsum() and skb_postpush_rcsum() pair invoked had a wrong result since they operated on an odd address for the hoplimit, while other computations were done on an even address. This mix doesn't work as-is with skb_postpull_rcsum(), skb_postpush_rcsum() pair as it always expects at least half-word alignment of input buffers, which is normally the case. Thus, instead of these helpers using csum_sub() and (implicitly) csum_add(), we need to use csum_block_sub(), csum_block_add(), respectively. For unaligned offsets, they rotate the sum to align it to a half-word boundary again, otherwise they work the same as csum_sub() and csum_add(). Adding __skb_postpull_rcsum(), __skb_postpush_rcsum() variants that take the offset as an input and adapting bpf_skb_store_bytes() to them fixes the hw csum failures again. The skb_postpull_rcsum(), skb_postpush_rcsum() helpers use a 0 constant for offset so that the compiler optimizes the offset & 1 test away and generates the same code as with csum_sub()/_add(). Fixes: 608cd71a9c ("tc: bpf: generalize pedit action") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>		2016-08-08 13:11:43 -07:00
..
datagram.c
dev.c	Merge branch 'salted-string-hash'	2016-07-28 12:26:31 -07:00
dev_addr_lists.c
dev_ioctl.c
devlink.c
drop_monitor.c
dst.c
dst_cache.c
ethtool.c
fib_rules.c
filter.c	bpf: fix checksum fixups on bpf_skb_store_bytes	2016-08-08 13:11:43 -07:00
flow.c
flow_dissector.c
gen_estimator.c
gen_stats.c
hwbm.c
link_watch.c
lwtunnel.c
Makefile
neighbour.c	net: neigh: disallow transition to NUD_STALE if lladdr is unchanged in neigh_update()	2016-07-26 14:25:20 -07:00
net-procfs.c
net-sysfs.c
net-sysfs.h
net-traces.c
net_namespace.c
netclassid_cgroup.c
netevent.c
netpoll.c
netprio_cgroup.c
pktgen.c
ptp_classifier.c
request_sock.c
rtnetlink.c	rtnl: protect do_setlink from IFLA_XDP_ATTACHED	2016-07-20 22:07:23 -07:00
scm.c
secure_seq.c
skbuff.c
sock.c
sock_diag.c
sock_reuseport.c
stream.c
sysctl_net_core.c
timestamping.c
tso.c
utils.c