From 4d4626f1c587a705d529bf646547484cc6e2df60 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Tue, 23 Jan 2018 12:14:29 +0100 Subject: [PATCH] batman-adv: add fixes for packet checksum handling Fixes "hw csum failure" log spam in batman-adv. --- ...d-fixes-for-packet-checksum-handling.patch | 102 ++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 patches/packages/routing/0002-batman-adv-add-fixes-for-packet-checksum-handling.patch diff --git a/patches/packages/routing/0002-batman-adv-add-fixes-for-packet-checksum-handling.patch b/patches/packages/routing/0002-batman-adv-add-fixes-for-packet-checksum-handling.patch new file mode 100644 index 00000000..7a7638bb --- /dev/null +++ b/patches/packages/routing/0002-batman-adv-add-fixes-for-packet-checksum-handling.patch @@ -0,0 +1,102 @@ +From: Matthias Schiffer +Date: Mon, 22 Jan 2018 20:41:41 +0100 +Subject: batman-adv: add fixes for packet checksum handling + +diff --git a/batman-adv/patches/0001-batman-adv-fix-packet-checksum-in-receive-path.patch b/batman-adv/patches/0001-batman-adv-fix-packet-checksum-in-receive-path.patch +new file mode 100644 +index 0000000000000000000000000000000000000000..ce1a5345be1405ccf034ab948b2061be46cda090 +--- /dev/null ++++ b/batman-adv/patches/0001-batman-adv-fix-packet-checksum-in-receive-path.patch +@@ -0,0 +1,44 @@ ++From 05cee97344804ffb2a8df87603663a098fd0cb36 Mon Sep 17 00:00:00 2001 ++Message-Id: <05cee97344804ffb2a8df87603663a098fd0cb36.1516705934.git.mschiffer@universe-factory.net> ++From: Matthias Schiffer ++Date: Mon, 22 Jan 2018 20:06:51 +0100 ++Subject: [PATCH 1/2] batman-adv: fix packet checksum in receive path ++ ++eth_type_trans() internally calls skb_pull(), which does not adjust the ++skb checksum; skb_postpull_rcsum() is necessary to avoid log spam of the ++form "bat0: hw csum failure" when packets with CHECKSUM_COMPLETE are ++received. ++ ++Note that in usual setups, packets don't reach batman-adv with ++CHECKSUM_COMPLETE (I assume NICs bail out of checksumming when they see ++batadv's ethtype?), which is why the log messages do nor occur on every ++system using batman-adv. I could reproduce this issue by stacking ++batman-adv on top of a VXLAN interface. ++ ++Signed-off-by: Matthias Schiffer ++--- ++ net/batman-adv/soft-interface.c | 8 +------- ++ 1 file changed, 1 insertion(+), 7 deletions(-) ++ ++diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c ++index 9f673cdf..6f7ce7a6 100644 ++--- a/net/batman-adv/soft-interface.c +++++ b/net/batman-adv/soft-interface.c ++@@ -451,13 +451,7 @@ void batadv_interface_rx(struct net_device *soft_iface, ++ ++ /* skb->dev & skb->pkt_type are set here */ ++ skb->protocol = eth_type_trans(skb, soft_iface); ++- ++- /* should not be necessary anymore as we use skb_pull_rcsum() ++- * TODO: please verify this and remove this TODO ++- * -- Dec 21st 2009, Simon Wunderlich ++- */ ++- ++- /* skb->ip_summed = CHECKSUM_UNNECESSARY; */ +++ skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); ++ ++ batadv_inc_counter(bat_priv, BATADV_CNT_RX); ++ batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES, ++-- ++2.16.1 ++ +diff --git a/batman-adv/patches/0002-batman-adv-invalidate-checksum-on-fragment-reassembl.patch b/batman-adv/patches/0002-batman-adv-invalidate-checksum-on-fragment-reassembl.patch +new file mode 100644 +index 0000000000000000000000000000000000000000..957fc345846acde05345963bcd66eed47b167358 +--- /dev/null ++++ b/batman-adv/patches/0002-batman-adv-invalidate-checksum-on-fragment-reassembl.patch +@@ -0,0 +1,42 @@ ++From 3f5713999a5f61ed7221944276393b4ff40a9416 Mon Sep 17 00:00:00 2001 ++Message-Id: <3f5713999a5f61ed7221944276393b4ff40a9416.1516705934.git.mschiffer@universe-factory.net> ++In-Reply-To: <05cee97344804ffb2a8df87603663a098fd0cb36.1516705934.git.mschiffer@universe-factory.net> ++References: <05cee97344804ffb2a8df87603663a098fd0cb36.1516705934.git.mschiffer@universe-factory.net> ++From: Matthias Schiffer ++Date: Tue, 23 Jan 2018 10:24:45 +0100 ++Subject: [PATCH 2/2] batman-adv: invalidate checksum on fragment reassembly ++ ++A more sophisticated implementation could try to combine fragment checksums ++when all fragments have CHECKSUM_COMPLETE and are split at even offsets. ++For now, we just set ip_summed to CHECKSUM_NONE to avoid "hw csum failure" ++warnings in the kernel log when fragmented frames are received. In ++consequence, skb_pull_rcsum() can be replaced with skb_pull(). ++ ++Note that in usual setups, packets don't reach batman-adv with ++CHECKSUM_COMPLETE (I assume NICs bail out of checksumming when they see ++batadv's ethtype?), which is why the log messages do nor occur on every ++system using batman-adv. I could reproduce this issue by stacking ++batman-adv on top of a VXLAN interface. ++ ++Signed-off-by: Matthias Schiffer ++--- ++ net/batman-adv/fragmentation.c | 3 ++- ++ 1 file changed, 2 insertions(+), 1 deletion(-) ++ ++diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c ++index ebe6e389..1bb2b43f 100644 ++--- a/net/batman-adv/fragmentation.c +++++ b/net/batman-adv/fragmentation.c ++@@ -287,7 +287,8 @@ batadv_frag_merge_packets(struct hlist_head *chain) ++ /* Move the existing MAC header to just before the payload. (Override ++ * the fragment header.) ++ */ ++- skb_pull_rcsum(skb_out, hdr_size); +++ skb_pull(skb_out, hdr_size); +++ skb_out->ip_summed = CHECKSUM_NONE; ++ memmove(skb_out->data - ETH_HLEN, skb_mac_header(skb_out), ETH_HLEN); ++ skb_set_mac_header(skb_out, -ETH_HLEN); ++ skb_reset_network_header(skb_out); ++-- ++2.16.1 ++