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