commit 6b649feafe10b293f4bd5a74aca95faf625ae525
author Tom Herbert <therbert@google.com> Fri May 23 08:47:40 2014 -0700
committer David S. Miller <davem@davemloft.net> Fri May 23 16:28:53 2014 -0400
tree 842991b315c84e51fa4c2ececfba60e2992944b9
parent 1c19448c9ba6545b80ded18488a64a7f3d8e6998

l2tp: Add support for zero IPv6 checksums

Added new L2TP configuration options to allow TX and RX of
zero checksums in IPv6. Default is not to use them.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_core.c

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index a118610..3795580 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1102,7 +1102,9 @@
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct udphdr *uh = udp_hdr(skb);
 
-	if (!skb_dst(skb) || !skb_dst(skb)->dev ||
+	if (udp_get_no_check6_tx(sk))
+		skb->ip_summed = CHECKSUM_NONE;
+	else if (!skb_dst(skb) || !skb_dst(skb)->dev ||
 	    !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
 		__wsum csum = skb_checksum(skb, 0, udp_len, 0);
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -1435,6 +1437,11 @@
 					     sizeof(udp6_addr), 0);
 			if (err < 0)
 				goto out;
+
+			if (cfg->udp6_zero_tx_checksums)
+				udp_set_no_check6_tx(sock->sk, true);
+			if (cfg->udp6_zero_rx_checksums)
+				udp_set_no_check6_rx(sock->sk, true);
 		} else
 #endif
 		{

net/l2tp/l2tp_core.h

diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 3f93ccd..68aa9ff 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -162,7 +162,9 @@
 #endif
 	u16			local_udp_port;
 	u16			peer_udp_port;
-	unsigned int		use_udp_checksums:1;
+	unsigned int		use_udp_checksums:1,
+				udp6_zero_tx_checksums:1,
+				udp6_zero_rx_checksums:1;
 };
 
 struct l2tp_tunnel {

net/l2tp/l2tp_netlink.c

diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index f3d331b..0ac907a 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -161,6 +161,13 @@
 			cfg.peer_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_DPORT]);
 		if (info->attrs[L2TP_ATTR_UDP_CSUM])
 			cfg.use_udp_checksums = nla_get_flag(info->attrs[L2TP_ATTR_UDP_CSUM]);
+
+#if IS_ENABLED(CONFIG_IPV6)
+		if (info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX])
+			cfg.udp6_zero_tx_checksums = nla_get_flag(info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
+		if (info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX])
+			cfg.udp6_zero_rx_checksums = nla_get_flag(info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
+#endif
 	}
 
 	if (info->attrs[L2TP_ATTR_DEBUG])