1 files changed, 447 insertions, 0 deletions

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
new file mode 100644
index 000000000..15c8eef1e
--- /dev/null
+++ b/net/ipv6/ip6_offload.c
@@ -0,0 +1,447 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	IPV6 GSO/GRO offload support
+ *	Linux INET6 implementation
+ */
+
+#include <linux/kernel.h>
+#include <linux/socket.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/printk.h>
+
+#include <net/protocol.h>
+#include <net/ipv6.h>
+#include <net/inet_common.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+
+#include "ip6_offload.h"
+
+/* All GRO functions are always builtin, except UDP over ipv6, which lays in
+ * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
+ * when ipv6 is built as a module
+ */
+#if IS_BUILTIN(CONFIG_IPV6)
+#define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
+#else
+#define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
+#endif
+
+#define indirect_call_gro_receive_l4(f2, f1, cb, head, skb)	\
+({								\
+	unlikely(gro_recursion_inc_test(skb)) ?			\
+		NAPI_GRO_CB(skb)->flush |= 1, NULL :		\
+		INDIRECT_CALL_L4(cb, f2, f1, head, skb);	\
+})
+
+static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
+{
+	const struct net_offload *ops = NULL;
+
+	for (;;) {
+		struct ipv6_opt_hdr *opth;
+		int len;
+
+		if (proto != NEXTHDR_HOP) {
+			ops = rcu_dereference(inet6_offloads[proto]);
+
+			if (unlikely(!ops))
+				break;
+
+			if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
+				break;
+		}
+
+		if (unlikely(!pskb_may_pull(skb, 8)))
+			break;
+
+		opth = (void *)skb->data;
+		len = ipv6_optlen(opth);
+
+		if (unlikely(!pskb_may_pull(skb, len)))
+			break;
+
+		opth = (void *)skb->data;
+		proto = opth->nexthdr;
+		__skb_pull(skb, len);
+	}
+
+	return proto;
+}
+
+static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
+	netdev_features_t features)
+{
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	struct ipv6hdr *ipv6h;
+	const struct net_offload *ops;
+	int proto;
+	struct frag_hdr *fptr;
+	unsigned int payload_len;
+	u8 *prevhdr;
+	int offset = 0;
+	bool encap, udpfrag;
+	int nhoff;
+	bool gso_partial;
+
+	skb_reset_network_header(skb);
+	nhoff = skb_network_header(skb) - skb_mac_header(skb);
+	if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
+		goto out;
+
+	encap = SKB_GSO_CB(skb)->encap_level > 0;
+	if (encap)
+		features &= skb->dev->hw_enc_features;
+	SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
+
+	ipv6h = ipv6_hdr(skb);
+	__skb_pull(skb, sizeof(*ipv6h));
+	segs = ERR_PTR(-EPROTONOSUPPORT);
+
+	proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
+
+	if (skb->encapsulation &&
+	    skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
+		udpfrag = proto == IPPROTO_UDP && encap &&
+			  (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
+	else
+		udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
+			  (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
+
+	ops = rcu_dereference(inet6_offloads[proto]);
+	if (likely(ops && ops->callbacks.gso_segment)) {
+		skb_reset_transport_header(skb);
+		segs = ops->callbacks.gso_segment(skb, features);
+		if (!segs)
+			skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
+	}
+
+	if (IS_ERR_OR_NULL(segs))
+		goto out;
+
+	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
+
+	for (skb = segs; skb; skb = skb->next) {
+		ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
+		if (gso_partial && skb_is_gso(skb))
+			payload_len = skb_shinfo(skb)->gso_size +
+				      SKB_GSO_CB(skb)->data_offset +
+				      skb->head - (unsigned char *)(ipv6h + 1);
+		else
+			payload_len = skb->len - nhoff - sizeof(*ipv6h);
+		ipv6h->payload_len = htons(payload_len);
+		skb->network_header = (u8 *)ipv6h - skb->head;
+		skb_reset_mac_len(skb);
+
+		if (udpfrag) {
+			int err = ip6_find_1stfragopt(skb, &prevhdr);
+			if (err < 0) {
+				kfree_skb_list(segs);
+				return ERR_PTR(err);
+			}
+			fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
+			fptr->frag_off = htons(offset);
+			if (skb->next)
+				fptr->frag_off |= htons(IP6_MF);
+			offset += (ntohs(ipv6h->payload_len) -
+				   sizeof(struct frag_hdr));
+		}
+		if (encap)
+			skb_reset_inner_headers(skb);
+	}
+
+out:
+	return segs;
+}
+
+/* Return the total length of all the extension hdrs, following the same
+ * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
+ */
+static int ipv6_exthdrs_len(struct ipv6hdr *iph,
+			    const struct net_offload **opps)
+{
+	struct ipv6_opt_hdr *opth = (void *)iph;
+	int len = 0, proto, optlen = sizeof(*iph);
+
+	proto = iph->nexthdr;
+	for (;;) {
+		if (proto != NEXTHDR_HOP) {
+			*opps = rcu_dereference(inet6_offloads[proto]);
+			if (unlikely(!(*opps)))
+				break;
+			if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
+				break;
+		}
+		opth = (void *)opth + optlen;
+		optlen = ipv6_optlen(opth);
+		len += optlen;
+		proto = opth->nexthdr;
+	}
+	return len;
+}
+
+INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
+							 struct sk_buff *skb)
+{
+	const struct net_offload *ops;
+	struct sk_buff *pp = NULL;
+	struct sk_buff *p;
+	struct ipv6hdr *iph;
+	unsigned int nlen;
+	unsigned int hlen;
+	unsigned int off;
+	u16 flush = 1;
+	int proto;
+
+	off = skb_gro_offset(skb);
+	hlen = off + sizeof(*iph);
+	iph = skb_gro_header_fast(skb, off);
+	if (skb_gro_header_hard(skb, hlen)) {
+		iph = skb_gro_header_slow(skb, hlen, off);
+		if (unlikely(!iph))
+			goto out;
+	}
+
+	skb_set_network_header(skb, off);
+	skb_gro_pull(skb, sizeof(*iph));
+	skb_set_transport_header(skb, skb_gro_offset(skb));
+
+	flush += ntohs(iph->payload_len) != skb_gro_len(skb);
+
+	rcu_read_lock();
+	proto = iph->nexthdr;
+	ops = rcu_dereference(inet6_offloads[proto]);
+	if (!ops || !ops->callbacks.gro_receive) {
+		__pskb_pull(skb, skb_gro_offset(skb));
+		skb_gro_frag0_invalidate(skb);
+		proto = ipv6_gso_pull_exthdrs(skb, proto);
+		skb_gro_pull(skb, -skb_transport_offset(skb));
+		skb_reset_transport_header(skb);
+		__skb_push(skb, skb_gro_offset(skb));
+
+		ops = rcu_dereference(inet6_offloads[proto]);
+		if (!ops || !ops->callbacks.gro_receive)
+			goto out_unlock;
+
+		iph = ipv6_hdr(skb);
+	}
+
+	NAPI_GRO_CB(skb)->proto = proto;
+
+	flush--;
+	nlen = skb_network_header_len(skb);
+
+	list_for_each_entry(p, head, list) {
+		const struct ipv6hdr *iph2;
+		__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
+
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		iph2 = (struct ipv6hdr *)(p->data + off);
+		first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
+
+		/* All fields must match except length and Traffic Class.
+		 * XXX skbs on the gro_list have all been parsed and pulled
+		 * already so we don't need to compare nlen
+		 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
+		 * memcmp() alone below is sufficient, right?
+		 */
+		 if ((first_word & htonl(0xF00FFFFF)) ||
+		    !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
+		    !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
+		    *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
+not_same_flow:
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+		if (unlikely(nlen > sizeof(struct ipv6hdr))) {
+			if (memcmp(iph + 1, iph2 + 1,
+				   nlen - sizeof(struct ipv6hdr)))
+				goto not_same_flow;
+		}
+		/* flush if Traffic Class fields are different */
+		NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
+		NAPI_GRO_CB(p)->flush |= flush;
+
+		/* If the previous IP ID value was based on an atomic
+		 * datagram we can overwrite the value and ignore it.
+		 */
+		if (NAPI_GRO_CB(skb)->is_atomic)
+			NAPI_GRO_CB(p)->flush_id = 0;
+	}
+
+	NAPI_GRO_CB(skb)->is_atomic = true;
+	NAPI_GRO_CB(skb)->flush |= flush;
+
+	skb_gro_postpull_rcsum(skb, iph, nlen);
+
+	pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
+					 ops->callbacks.gro_receive, head, skb);
+
+out_unlock:
+	rcu_read_unlock();
+
+out:
+	skb_gro_flush_final(skb, pp, flush);
+
+	return pp;
+}
+
+static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
+					      struct sk_buff *skb)
+{
+	/* Common GRO receive for SIT and IP6IP6 */
+
+	if (NAPI_GRO_CB(skb)->encap_mark) {
+		NAPI_GRO_CB(skb)->flush = 1;
+		return NULL;
+	}
+
+	NAPI_GRO_CB(skb)->encap_mark = 1;
+
+	return ipv6_gro_receive(head, skb);
+}
+
+static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
+					  struct sk_buff *skb)
+{
+	/* Common GRO receive for SIT and IP6IP6 */
+
+	if (NAPI_GRO_CB(skb)->encap_mark) {
+		NAPI_GRO_CB(skb)->flush = 1;
+		return NULL;
+	}
+
+	NAPI_GRO_CB(skb)->encap_mark = 1;
+
+	return inet_gro_receive(head, skb);
+}
+
+INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	const struct net_offload *ops;
+	struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
+	int err = -ENOSYS;
+
+	if (skb->encapsulation) {
+		skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
+		skb_set_inner_network_header(skb, nhoff);
+	}
+
+	iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
+
+	rcu_read_lock();
+
+	nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
+	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+		goto out_unlock;
+
+	err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
+			       udp6_gro_complete, skb, nhoff);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return err;
+}
+
+static int sit_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	skb->encapsulation = 1;
+	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
+	return ipv6_gro_complete(skb, nhoff);
+}
+
+static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	skb->encapsulation = 1;
+	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
+	return ipv6_gro_complete(skb, nhoff);
+}
+
+static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	skb->encapsulation = 1;
+	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
+	return inet_gro_complete(skb, nhoff);
+}
+
+static struct packet_offload ipv6_packet_offload __read_mostly = {
+	.type = cpu_to_be16(ETH_P_IPV6),
+	.callbacks = {
+		.gso_segment = ipv6_gso_segment,
+		.gro_receive = ipv6_gro_receive,
+		.gro_complete = ipv6_gro_complete,
+	},
+};
+
+static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
+				       netdev_features_t features)
+{
+	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
+		return ERR_PTR(-EINVAL);
+
+	return ipv6_gso_segment(skb, features);
+}
+
+static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
+					  netdev_features_t features)
+{
+	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
+		return ERR_PTR(-EINVAL);
+
+	return inet_gso_segment(skb, features);
+}
+
+static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
+					  netdev_features_t features)
+{
+	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
+		return ERR_PTR(-EINVAL);
+
+	return ipv6_gso_segment(skb, features);
+}
+
+static const struct net_offload sit_offload = {
+	.callbacks = {
+		.gso_segment	= sit_gso_segment,
+		.gro_receive    = sit_ip6ip6_gro_receive,
+		.gro_complete   = sit_gro_complete,
+	},
+};
+
+static const struct net_offload ip4ip6_offload = {
+	.callbacks = {
+		.gso_segment	= ip4ip6_gso_segment,
+		.gro_receive    = ip4ip6_gro_receive,
+		.gro_complete   = ip4ip6_gro_complete,
+	},
+};
+
+static const struct net_offload ip6ip6_offload = {
+	.callbacks = {
+		.gso_segment	= ip6ip6_gso_segment,
+		.gro_receive    = sit_ip6ip6_gro_receive,
+		.gro_complete   = ip6ip6_gro_complete,
+	},
+};
+static int __init ipv6_offload_init(void)
+{
+
+	if (tcpv6_offload_init() < 0)
+		pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
+	if (ipv6_exthdrs_offload_init() < 0)
+		pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
+
+	dev_add_offload(&ipv6_packet_offload);
+
+	inet_add_offload(&sit_offload, IPPROTO_IPV6);
+	inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
+	inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
+
+	return 0;
+}
+
+fs_initcall(ipv6_offload_init);