net/l2tp: add support for L2TP over IPv6 UDP
Now that encap_rcv() works on IPv6 UDP sockets, wire L2TP up to IPv6.
Support has been tested with and without hardware offloading. This
version fixes the L2TP over localhost issue with incorrect checksums
being reported.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index f6732b6..e91d559 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 @@
{
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)
+ if (sk->sk_no_check || skb_csum_unnecessary(skb))
return 0;
- inet = inet_sk(sk);
- psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
- IPPROTO_UDP, 0);
+#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;
+ 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 @@
/* 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 @@
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 @@
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 @@
/* 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();
}