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-rw-r--r--include/net/gso.h109
1 files changed, 109 insertions, 0 deletions
diff --git a/include/net/gso.h b/include/net/gso.h
new file mode 100644
index 000000000000..29975440cad5
--- /dev/null
+++ b/include/net/gso.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _NET_GSO_H
+#define _NET_GSO_H
+
+#include <linux/skbuff.h>
+
+/* Keeps track of mac header offset relative to skb->head.
+ * It is useful for TSO of Tunneling protocol. e.g. GRE.
+ * For non-tunnel skb it points to skb_mac_header() and for
+ * tunnel skb it points to outer mac header.
+ * Keeps track of level of encapsulation of network headers.
+ */
+struct skb_gso_cb {
+ union {
+ int mac_offset;
+ int data_offset;
+ };
+ int encap_level;
+ __wsum csum;
+ __u16 csum_start;
+};
+#define SKB_GSO_CB_OFFSET 32
+#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_GSO_CB_OFFSET))
+
+static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
+{
+ return (skb_mac_header(inner_skb) - inner_skb->head) -
+ SKB_GSO_CB(inner_skb)->mac_offset;
+}
+
+static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
+{
+ int new_headroom, headroom;
+ int ret;
+
+ headroom = skb_headroom(skb);
+ ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
+ if (ret)
+ return ret;
+
+ new_headroom = skb_headroom(skb);
+ SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
+ return 0;
+}
+
+static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
+{
+ /* Do not update partial checksums if remote checksum is enabled. */
+ if (skb->remcsum_offload)
+ return;
+
+ SKB_GSO_CB(skb)->csum = res;
+ SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
+}
+
+/* Compute the checksum for a gso segment. First compute the checksum value
+ * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
+ * then add in skb->csum (checksum from csum_start to end of packet).
+ * skb->csum and csum_start are then updated to reflect the checksum of the
+ * resultant packet starting from the transport header-- the resultant checksum
+ * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
+ * header.
+ */
+static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
+{
+ unsigned char *csum_start = skb_transport_header(skb);
+ int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
+ __wsum partial = SKB_GSO_CB(skb)->csum;
+
+ SKB_GSO_CB(skb)->csum = res;
+ SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
+
+ return csum_fold(csum_partial(csum_start, plen, partial));
+}
+
+struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
+ netdev_features_t features, bool tx_path);
+
+static inline struct sk_buff *skb_gso_segment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ return __skb_gso_segment(skb, features, true);
+}
+
+struct sk_buff *skb_eth_gso_segment(struct sk_buff *skb,
+ netdev_features_t features, __be16 type);
+
+struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb,
+ netdev_features_t features);
+
+bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu);
+
+bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len);
+
+static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol,
+ int pulled_hlen, u16 mac_offset,
+ int mac_len)
+{
+ skb->protocol = protocol;
+ skb->encapsulation = 1;
+ skb_push(skb, pulled_hlen);
+ skb_reset_transport_header(skb);
+ skb->mac_header = mac_offset;
+ skb->network_header = skb->mac_header + mac_len;
+ skb->mac_len = mac_len;
+}
+
+#endif /* _NET_GSO_H */