1 files changed, 77 insertions, 12 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index f6732b6c758b..e91d55924d94 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -53,6 +53,9 @@
 #include <net/inet_common.h>
 #include <net/xfrm.h>
 #include <net/protocol.h>
+#include <net/inet6_connection_sock.h>
+#include <net/inet_ecn.h>
+#include <net/ip6_route.h>
 
 #include <asm/byteorder.h>
 #include <linux/atomic.h>
@@ -446,21 +449,43 @@ static inline int l2tp_verify_udp_checksum(struct sock *sk,
 {
 	struct udphdr *uh = udp_hdr(skb);
 	u16 ulen = ntohs(uh->len);
-	struct inet_sock *inet;
 	__wsum psum;
 
-	if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
-		return 0;
-
-	inet = inet_sk(sk);
-	psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
-				  IPPROTO_UDP, 0);
-
-	if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
-	    !csum_fold(csum_add(psum, skb->csum)))
+	if (sk->sk_no_check || skb_csum_unnecessary(skb))
 		return 0;
 
-	skb->csum = psum;
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == PF_INET6) {
+		if (!uh->check) {
+			LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
+			return 1;
+		}
+		if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
+		    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+				     &ipv6_hdr(skb)->daddr, ulen,
+				     IPPROTO_UDP, skb->csum)) {
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+			return 0;
+		}
+		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+							 &ipv6_hdr(skb)->daddr,
+							 skb->len, IPPROTO_UDP,
+							 0));
+	} else
+#endif
+	{
+		struct inet_sock *inet;
+		if (!uh->check)
+			return 0;
+		inet = inet_sk(sk);
+		psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
+					  ulen, IPPROTO_UDP, 0);
+
+		if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
+		    !csum_fold(csum_add(psum, skb->csum)))
+			return 0;
+		skb->csum = psum;
+	}
 
 	return __skb_checksum_complete(skb);
 }
@@ -988,7 +1013,12 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
 
 	/* Queue the packet to IP for output */
 	skb->local_df = 1;
-	error = ip_queue_xmit(skb, fl);
+#if IS_ENABLED(CONFIG_IPV6)
+	if (skb->sk->sk_family == PF_INET6)
+		error = inet6_csk_xmit(skb, NULL);
+	else
+#endif
+		error = ip_queue_xmit(skb, fl);
 
 	/* Update stats */
 	if (error >= 0) {
@@ -1021,6 +1051,31 @@ static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
 	skb->destructor = l2tp_sock_wfree;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
+static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb,
+				int udp_len)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct udphdr *uh = udp_hdr(skb);
+
+	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;
+		uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len,
+					    IPPROTO_UDP, csum);
+		if (uh->check == 0)
+			uh->check = CSUM_MANGLED_0;
+	} else {
+		skb->ip_summed = CHECKSUM_PARTIAL;
+		skb->csum_start = skb_transport_header(skb) - skb->head;
+		skb->csum_offset = offsetof(struct udphdr, check);
+		uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr,
+					     udp_len, IPPROTO_UDP, 0);
+	}
+}
+#endif
+
 /* If caller requires the skb to have a ppp header, the header must be
  * inserted in the skb data before calling this function.
  */
@@ -1089,6 +1144,11 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
 		uh->check = 0;
 
 		/* Calculate UDP checksum if configured to do so */
+#if IS_ENABLED(CONFIG_IPV6)
+		if (sk->sk_family == PF_INET6)
+			l2tp_xmit_ipv6_csum(sk, skb, udp_len);
+		else
+#endif
 		if (sk->sk_no_check == UDP_CSUM_NOXMIT)
 			skb->ip_summed = CHECKSUM_NONE;
 		else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
@@ -1424,6 +1484,11 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 		/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
 		udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
 		udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
+#if IS_ENABLED(CONFIG_IPV6)
+		if (sk->sk_family == PF_INET6)
+			udpv6_encap_enable();
+		else
+#endif
 		udp_encap_enable();
 	}