1 files changed, 344 insertions, 44 deletions

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 32e78924e246..740ae099a0d9 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -38,21 +38,17 @@ static inline struct fou *fou_from_sock(struct sock *sk)
 	return sk->sk_user_data;
 }
 
-static int fou_udp_encap_recv_deliver(struct sk_buff *skb,
-				      u8 protocol, size_t len)
+static void fou_recv_pull(struct sk_buff *skb, size_t len)
 {
 	struct iphdr *iph = ip_hdr(skb);
 
 	/* Remove 'len' bytes from the packet (UDP header and
-	 * FOU header if present), modify the protocol to the one
-	 * we found, and then call rcv_encap.
+	 * FOU header if present).
 	 */
 	iph->tot_len = htons(ntohs(iph->tot_len) - len);
 	__skb_pull(skb, len);
 	skb_postpull_rcsum(skb, udp_hdr(skb), len);
 	skb_reset_transport_header(skb);
-
-	return -protocol;
 }
 
 static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
@@ -62,16 +58,78 @@ static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
 	if (!fou)
 		return 1;
 
-	return fou_udp_encap_recv_deliver(skb, fou->protocol,
-					  sizeof(struct udphdr));
+	fou_recv_pull(skb, sizeof(struct udphdr));
+
+	return -fou->protocol;
+}
+
+static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
+				  void *data, int hdrlen, u8 ipproto)
+{
+	__be16 *pd = data;
+	u16 start = ntohs(pd[0]);
+	u16 offset = ntohs(pd[1]);
+	u16 poffset = 0;
+	u16 plen;
+	__wsum csum, delta;
+	__sum16 *psum;
+
+	if (skb->remcsum_offload) {
+		/* Already processed in GRO path */
+		skb->remcsum_offload = 0;
+		return guehdr;
+	}
+
+	if (start > skb->len - hdrlen ||
+	    offset > skb->len - hdrlen - sizeof(u16))
+		return NULL;
+
+	if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE))
+		__skb_checksum_complete(skb);
+
+	plen = hdrlen + offset + sizeof(u16);
+	if (!pskb_may_pull(skb, plen))
+		return NULL;
+	guehdr = (struct guehdr *)&udp_hdr(skb)[1];
+
+	if (ipproto == IPPROTO_IP && sizeof(struct iphdr) < plen) {
+		struct iphdr *ip = (struct iphdr *)(skb->data + hdrlen);
+
+		/* If next header happens to be IP we can skip that for the
+		 * checksum calculation since the IP header checksum is zero
+		 * if correct.
+		 */
+		poffset = ip->ihl * 4;
+	}
+
+	csum = csum_sub(skb->csum, skb_checksum(skb, poffset + hdrlen,
+						start - poffset - hdrlen, 0));
+
+	/* Set derived checksum in packet */
+	psum = (__sum16 *)(skb->data + hdrlen + offset);
+	delta = csum_sub(csum_fold(csum), *psum);
+	*psum = csum_fold(csum);
+
+	/* Adjust skb->csum since we changed the packet */
+	skb->csum = csum_add(skb->csum, delta);
+
+	return guehdr;
+}
+
+static int gue_control_message(struct sk_buff *skb, struct guehdr *guehdr)
+{
+	/* No support yet */
+	kfree_skb(skb);
+	return 0;
 }
 
 static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
 {
 	struct fou *fou = fou_from_sock(sk);
-	size_t len;
+	size_t len, optlen, hdrlen;
 	struct guehdr *guehdr;
-	struct udphdr *uh;
+	void *data;
+	u16 doffset = 0;
 
 	if (!fou)
 		return 1;
@@ -80,25 +138,61 @@ static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
 	if (!pskb_may_pull(skb, len))
 		goto drop;
 
-	uh = udp_hdr(skb);
-	guehdr = (struct guehdr *)&uh[1];
+	guehdr = (struct guehdr *)&udp_hdr(skb)[1];
+
+	optlen = guehdr->hlen << 2;
+	len += optlen;
 
-	len += guehdr->hlen << 2;
 	if (!pskb_may_pull(skb, len))
 		goto drop;
 
-	uh = udp_hdr(skb);
-	guehdr = (struct guehdr *)&uh[1];
+	/* guehdr may change after pull */
+	guehdr = (struct guehdr *)&udp_hdr(skb)[1];
 
-	if (guehdr->version != 0)
-		goto drop;
+	hdrlen = sizeof(struct guehdr) + optlen;
 
-	if (guehdr->flags) {
-		/* No support yet */
+	if (guehdr->version != 0 || validate_gue_flags(guehdr, optlen))
 		goto drop;
+
+	hdrlen = sizeof(struct guehdr) + optlen;
+
+	ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len);
+
+	/* Pull UDP header now, skb->data points to guehdr */
+	__skb_pull(skb, sizeof(struct udphdr));
+
+	/* Pull csum through the guehdr now . This can be used if
+	 * there is a remote checksum offload.
+	 */
+	skb_postpull_rcsum(skb, udp_hdr(skb), len);
+
+	data = &guehdr[1];
+
+	if (guehdr->flags & GUE_FLAG_PRIV) {
+		__be32 flags = *(__be32 *)(data + doffset);
+
+		doffset += GUE_LEN_PRIV;
+
+		if (flags & GUE_PFLAG_REMCSUM) {
+			guehdr = gue_remcsum(skb, guehdr, data + doffset,
+					     hdrlen, guehdr->proto_ctype);
+			if (!guehdr)
+				goto drop;
+
+			data = &guehdr[1];
+
+			doffset += GUE_PLEN_REMCSUM;
+		}
 	}
 
-	return fou_udp_encap_recv_deliver(skb, guehdr->next_hdr, len);
+	if (unlikely(guehdr->control))
+		return gue_control_message(skb, guehdr);
+
+	__skb_pull(skb, hdrlen);
+	skb_reset_transport_header(skb);
+
+	return -guehdr->proto_ctype;
+
 drop:
 	kfree_skb(skb);
 	return 0;
@@ -147,6 +241,66 @@ out_unlock:
 	return err;
 }
 
+static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
+				      struct guehdr *guehdr, void *data,
+				      size_t hdrlen, u8 ipproto)
+{
+	__be16 *pd = data;
+	u16 start = ntohs(pd[0]);
+	u16 offset = ntohs(pd[1]);
+	u16 poffset = 0;
+	u16 plen;
+	void *ptr;
+	__wsum csum, delta;
+	__sum16 *psum;
+
+	if (skb->remcsum_offload)
+		return guehdr;
+
+	if (start > skb_gro_len(skb) - hdrlen ||
+	    offset > skb_gro_len(skb) - hdrlen - sizeof(u16) ||
+	    !NAPI_GRO_CB(skb)->csum_valid || skb->remcsum_offload)
+		return NULL;
+
+	plen = hdrlen + offset + sizeof(u16);
+
+	/* Pull checksum that will be written */
+	if (skb_gro_header_hard(skb, off + plen)) {
+		guehdr = skb_gro_header_slow(skb, off + plen, off);
+		if (!guehdr)
+			return NULL;
+	}
+
+	ptr = (void *)guehdr + hdrlen;
+
+	if (ipproto == IPPROTO_IP &&
+	    (hdrlen + sizeof(struct iphdr) < plen)) {
+		struct iphdr *ip = (struct iphdr *)(ptr + hdrlen);
+
+		/* If next header happens to be IP we can skip
+		 * that for the checksum calculation since the
+		 * IP header checksum is zero if correct.
+		 */
+		poffset = ip->ihl * 4;
+	}
+
+	csum = csum_sub(NAPI_GRO_CB(skb)->csum,
+			csum_partial(ptr + poffset, start - poffset, 0));
+
+	/* Set derived checksum in packet */
+	psum = (__sum16 *)(ptr + offset);
+	delta = csum_sub(csum_fold(csum), *psum);
+	*psum = csum_fold(csum);
+
+	/* Adjust skb->csum since we changed the packet */
+	skb->csum = csum_add(skb->csum, delta);
+	NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
+
+	skb->remcsum_offload = 1;
+
+	return guehdr;
+}
+
 static struct sk_buff **gue_gro_receive(struct sk_buff **head,
 					struct sk_buff *skb)
 {
@@ -154,38 +308,64 @@ static struct sk_buff **gue_gro_receive(struct sk_buff **head,
 	const struct net_offload *ops;
 	struct sk_buff **pp = NULL;
 	struct sk_buff *p;
-	u8 proto;
 	struct guehdr *guehdr;
-	unsigned int hlen, guehlen;
-	unsigned int off;
+	size_t len, optlen, hdrlen, off;
+	void *data;
+	u16 doffset = 0;
 	int flush = 1;
 
 	off = skb_gro_offset(skb);
-	hlen = off + sizeof(*guehdr);
+	len = off + sizeof(*guehdr);
+
 	guehdr = skb_gro_header_fast(skb, off);
-	if (skb_gro_header_hard(skb, hlen)) {
-		guehdr = skb_gro_header_slow(skb, hlen, off);
+	if (skb_gro_header_hard(skb, len)) {
+		guehdr = skb_gro_header_slow(skb, len, off);
 		if (unlikely(!guehdr))
 			goto out;
 	}
 
-	proto = guehdr->next_hdr;
+	optlen = guehdr->hlen << 2;
+	len += optlen;
 
-	rcu_read_lock();
-	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
-	ops = rcu_dereference(offloads[proto]);
-	if (WARN_ON(!ops || !ops->callbacks.gro_receive))
-		goto out_unlock;
+	if (skb_gro_header_hard(skb, len)) {
+		guehdr = skb_gro_header_slow(skb, len, off);
+		if (unlikely(!guehdr))
+			goto out;
+	}
 
-	guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
+	if (unlikely(guehdr->control) || guehdr->version != 0 ||
+	    validate_gue_flags(guehdr, optlen))
+		goto out;
 
-	hlen = off + guehlen;
-	if (skb_gro_header_hard(skb, hlen)) {
-		guehdr = skb_gro_header_slow(skb, hlen, off);
-		if (unlikely(!guehdr))
-			goto out_unlock;
+	hdrlen = sizeof(*guehdr) + optlen;
+
+	/* Adjust NAPI_GRO_CB(skb)->csum to account for guehdr,
+	 * this is needed if there is a remote checkcsum offload.
+	 */
+	skb_gro_postpull_rcsum(skb, guehdr, hdrlen);
+
+	data = &guehdr[1];
+
+	if (guehdr->flags & GUE_FLAG_PRIV) {
+		__be32 flags = *(__be32 *)(data + doffset);
+
+		doffset += GUE_LEN_PRIV;
+
+		if (flags & GUE_PFLAG_REMCSUM) {
+			guehdr = gue_gro_remcsum(skb, off, guehdr,
+						 data + doffset, hdrlen,
+						 guehdr->proto_ctype);
+			if (!guehdr)
+				goto out;
+
+			data = &guehdr[1];
+
+			doffset += GUE_PLEN_REMCSUM;
+		}
 	}
 
+	skb_gro_pull(skb, hdrlen);
+
 	flush = 0;
 
 	for (p = *head; p; p = p->next) {
@@ -197,7 +377,7 @@ static struct sk_buff **gue_gro_receive(struct sk_buff **head,
 		guehdr2 = (struct guehdr *)(p->data + off);
 
 		/* Compare base GUE header to be equal (covers
-		 * hlen, version, next_hdr, and flags.
+		 * hlen, version, proto_ctype, and flags.
 		 */
 		if (guehdr->word != guehdr2->word) {
 			NAPI_GRO_CB(p)->same_flow = 0;
@@ -212,10 +392,11 @@ static struct sk_buff **gue_gro_receive(struct sk_buff **head,
 		}
 	}
 
-	skb_gro_pull(skb, guehlen);
-
-	/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
-	skb_gro_postpull_rcsum(skb, guehdr, guehlen);
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[guehdr->proto_ctype]);
+	if (WARN_ON(!ops || !ops->callbacks.gro_receive))
+		goto out_unlock;
 
 	pp = ops->callbacks.gro_receive(head, skb);
 
@@ -236,7 +417,7 @@ static int gue_gro_complete(struct sk_buff *skb, int nhoff)
 	u8 proto;
 	int err = -ENOENT;
 
-	proto = guehdr->next_hdr;
+	proto = guehdr->proto_ctype;
 
 	guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
 
@@ -487,6 +668,125 @@ static const struct genl_ops fou_nl_ops[] = {
 	},
 };
 
+static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
+			  struct flowi4 *fl4, u8 *protocol, __be16 sport)
+{
+	struct udphdr *uh;
+
+	skb_push(skb, sizeof(struct udphdr));
+	skb_reset_transport_header(skb);
+
+	uh = udp_hdr(skb);
+
+	uh->dest = e->dport;
+	uh->source = sport;
+	uh->len = htons(skb->len);
+	uh->check = 0;
+	udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
+		     fl4->saddr, fl4->daddr, skb->len);
+
+	*protocol = IPPROTO_UDP;
+}
+
+int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+		     u8 *protocol, struct flowi4 *fl4)
+{
+	bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
+	int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+	__be16 sport;
+
+	skb = iptunnel_handle_offloads(skb, csum, type);
+
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
+					       skb, 0, 0, false);
+	fou_build_udp(skb, e, fl4, protocol, sport);
+
+	return 0;
+}
+EXPORT_SYMBOL(fou_build_header);
+
+int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+		     u8 *protocol, struct flowi4 *fl4)
+{
+	bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
+	int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+	struct guehdr *guehdr;
+	size_t hdrlen, optlen = 0;
+	__be16 sport;
+	void *data;
+	bool need_priv = false;
+
+	if ((e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) &&
+	    skb->ip_summed == CHECKSUM_PARTIAL) {
+		csum = false;
+		optlen += GUE_PLEN_REMCSUM;
+		type |= SKB_GSO_TUNNEL_REMCSUM;
+		need_priv = true;
+	}
+
+	optlen += need_priv ? GUE_LEN_PRIV : 0;
+
+	skb = iptunnel_handle_offloads(skb, csum, type);
+
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	/* Get source port (based on flow hash) before skb_push */
+	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
+					       skb, 0, 0, false);
+
+	hdrlen = sizeof(struct guehdr) + optlen;
+
+	skb_push(skb, hdrlen);
+
+	guehdr = (struct guehdr *)skb->data;
+
+	guehdr->control = 0;
+	guehdr->version = 0;
+	guehdr->hlen = optlen >> 2;
+	guehdr->flags = 0;
+	guehdr->proto_ctype = *protocol;
+
+	data = &guehdr[1];
+
+	if (need_priv) {
+		__be32 *flags = data;
+
+		guehdr->flags |= GUE_FLAG_PRIV;
+		*flags = 0;
+		data += GUE_LEN_PRIV;
+
+		if (type & SKB_GSO_TUNNEL_REMCSUM) {
+			u16 csum_start = skb_checksum_start_offset(skb);
+			__be16 *pd = data;
+
+			if (csum_start < hdrlen)
+				return -EINVAL;
+
+			csum_start -= hdrlen;
+			pd[0] = htons(csum_start);
+			pd[1] = htons(csum_start + skb->csum_offset);
+
+			if (!skb_is_gso(skb)) {
+				skb->ip_summed = CHECKSUM_NONE;
+				skb->encapsulation = 0;
+			}
+
+			*flags |= GUE_PFLAG_REMCSUM;
+			data += GUE_PLEN_REMCSUM;
+		}
+
+	}
+
+	fou_build_udp(skb, e, fl4, protocol, sport);
+
+	return 0;
+}
+EXPORT_SYMBOL(gue_build_header);
+
 static int __init fou_init(void)
 {
 	int ret;