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 +