pintos-os.org Git - openvswitch/blob - datapath/checksum.h

   1 /*
   2  * Copyright (c) 2010, 2011 Nicira Networks.
   3  * Distributed under the terms of the GNU GPL version 2.
   4  *
   5  * Significant portions of this file may be copied from parts of the Linux
   6  * kernel, by Linus Torvalds and others.
   7  */
   8
   9 #ifndef CHECKSUM_H
  10 #define CHECKSUM_H 1
  11
  12 #include <linux/skbuff.h>
  13 #include <linux/version.h>
  14
  15 #include <net/checksum.h>
  16
  17 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22) || \
  18         (defined(CONFIG_XEN) && defined(HAVE_PROTO_DATA_VALID))
  19 #define NEED_CSUM_NORMALIZE
  20 #endif
  21
  22 /* These are the same values as the checksum constants in 2.6.22+. */
  23 enum csum_type {
  24         OVS_CSUM_NONE = 0,
  25         OVS_CSUM_UNNECESSARY = 1,
  26         OVS_CSUM_COMPLETE = 2,
  27         OVS_CSUM_PARTIAL = 3,
  28 };
  29
  30 #ifdef NEED_CSUM_NORMALIZE
  31 int compute_ip_summed(struct sk_buff *skb, bool xmit);
  32 void forward_ip_summed(struct sk_buff *skb, bool xmit);
  33 u8 get_ip_summed(struct sk_buff *skb);
  34 void set_ip_summed(struct sk_buff *skb, u8 ip_summed);
  35 void get_skb_csum_pointers(const struct sk_buff *skb, u16 *csum_start,
  36                            u16 *csum_offset);
  37 void set_skb_csum_pointers(struct sk_buff *skb, u16 csum_start, u16 csum_offset);
  38 #else
  39 static inline int compute_ip_summed(struct sk_buff *skb, bool xmit)
  40 {
  41         return 0;
  42 }
  43
  44 static inline void forward_ip_summed(struct sk_buff *skb, bool xmit) { }
  45
  46 static inline u8 get_ip_summed(struct sk_buff *skb)
  47 {
  48         return skb->ip_summed;
  49 }
  50
  51 static inline void set_ip_summed(struct sk_buff *skb, u8 ip_summed)
  52 {
  53         skb->ip_summed = ip_summed;
  54 }
  55
  56 static inline void get_skb_csum_pointers(const struct sk_buff *skb,
  57                                          u16 *csum_start, u16 *csum_offset)
  58 {
  59         *csum_start = skb->csum_start;
  60         *csum_offset = skb->csum_offset;
  61 }
  62
  63 static inline void set_skb_csum_pointers(struct sk_buff *skb, u16 csum_start,
  64                                          u16 csum_offset)
  65 {
  66         skb->csum_start = csum_start;
  67         skb->csum_offset = csum_offset;
  68 }
  69 #endif
  70
  71 /* This is really compatibility code that belongs in the compat directory.
  72  * However, it needs access to our normalized checksum values, so put it here.
  73  */
  74 #if defined(NEED_CSUM_NORMALIZE) || LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
  75 #define inet_proto_csum_replace4 rpl_inet_proto_csum_replace4
  76 static inline void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
  77                                             __be32 from, __be32 to,
  78                                             int pseudohdr)
  79 {
  80         __be32 diff[] = { ~from, to };
  81
  82         if (get_ip_summed(skb) != OVS_CSUM_PARTIAL) {
  83                 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff),
  84                                 ~csum_unfold(*sum)));
  85                 if (get_ip_summed(skb) == OVS_CSUM_COMPLETE && pseudohdr)
  86                         skb->csum = ~csum_partial((char *)diff, sizeof(diff),
  87                                                 ~skb->csum);
  88         } else if (pseudohdr)
  89                 *sum = ~csum_fold(csum_partial((char *)diff, sizeof(diff),
  90                                 csum_unfold(*sum)));
  91 }
  92 #endif
  93
  94 #ifdef NEED_CSUM_NORMALIZE
  95 static inline void update_csum_start(struct sk_buff *skb, int delta)
  96 {
  97         if (get_ip_summed(skb) == OVS_CSUM_PARTIAL) {
  98                 u16 csum_start, csum_offset;
  99
 100                 get_skb_csum_pointers(skb, &csum_start, &csum_offset);
 101                 set_skb_csum_pointers(skb, csum_start + delta, csum_offset);
 102         }
 103 }
 104
 105 static inline int rpl_pskb_expand_head(struct sk_buff *skb, int nhead,
 106                                        int ntail, gfp_t gfp_mask)
 107 {
 108         int err;
 109         int old_headroom = skb_headroom(skb);
 110
 111         err = pskb_expand_head(skb, nhead, ntail, gfp_mask);
 112         if (unlikely(err))
 113                 return err;
 114
 115         update_csum_start(skb, skb_headroom(skb) - old_headroom);
 116
 117         return 0;
 118 }
 119 #define pskb_expand_head rpl_pskb_expand_head
 120
 121 static inline unsigned char *rpl__pskb_pull_tail(struct sk_buff *skb,
 122                                                   int delta)
 123 {
 124         unsigned char *ret;
 125         int old_headroom = skb_headroom(skb);
 126
 127         ret = __pskb_pull_tail(skb, delta);
 128         if (unlikely(!ret))
 129                 return ret;
 130
 131         update_csum_start(skb, skb_headroom(skb) - old_headroom);
 132
 133         return ret;
 134 }
 135 #define __pskb_pull_tail rpl__pskb_pull_tail
 136 #endif
 137
 138 #endif /* checksum.h */