@@ -2741,6 +2741,95 @@ static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
0 : __skb_checksum_complete(skb);
}
+/* Try to validate checksum based on unnecessary or zero checksum
+ * received.
+ *
+ * Returns true if the checksum has been validated, false otherwise
+ * (checksum complete is needed).
+ */
+static inline bool __skb_checksum_validate_unnecessary(struct sk_buff *skb,
+ bool zero_okay,
+ __sum16 check)
+{
+ if (skb_csum_unnecessary(skb)) {
+ return true;
+ } else if (zero_okay && !check) {
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ return true;
+ }
+
+ return false;
+}
+
+/* Validate (init) checksum based on checksum complete.
+ *
+ * Return values:
+ * 0: checksum is validated or try to in skb_checksum_complete. In the latter
+ * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
+ * checksum is stored in skb->csum for use in __skb_checksum_complete
+ * non-zero: value of invalid checksum
+ *
+ */
+static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
+ bool complete,
+ __wsum psum)
+{
+ if (skb->ip_summed == CHECKSUM_COMPLETE) {
+ if (!csum_fold(csum_add(psum, skb->csum))) {
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ return 0;
+ }
+ }
+
+ skb->csum = psum;
+
+ if (complete || skb->len <= 76)
+ return __skb_checksum_complete(skb);
+
+ return 0;
+}
+
+static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
+{
+ return 0;
+}
+
+/* Perform checksum validate (init). Note that this is a macro since we only
+ * want to calculate the pseudo header which is an input function if necessary.
+ * First we try to validate without any computation (checksum unnecessary) and
+ * then calculate based on checksum complete calling the function to compute
+ * pseudo header.
+ *
+ * Return values:
+ * 0: checksum is validated or try to in skb_checksum_complete
+ * non-zero: value of invalid checksum
+ */
+#define __skb_checksum_validate(skb, proto, complete, \
+ zero_okay, check, compute_pseudo) \
+({ \
+ __sum16 __ret = 0; \
+ if (!__skb_checksum_validate_unnecessary(skb, zero_okay, check))\
+ __ret = __skb_checksum_validate_complete(skb, \
+ complete, compute_pseudo(skb, proto)); \
+ __ret; \
+})
+
+#define skb_checksum_init(skb, proto, compute_pseudo) \
+ __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
+
+#define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
+ __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
+
+#define skb_checksum_validate(skb, proto, compute_pseudo) \
+ __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
+
+#define skb_checksum_validate_zero_check(skb, proto, check, \
+ compute_pseudo) \
+ __skb_checksum_validate_(skb, proto, true, true, check, compute_pseudo)
+
+#define skb_checksum_simple_validate(skb) \
+ __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
+
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
void nf_conntrack_destroy(struct nf_conntrack *nfct);
static inline void nf_conntrack_put(struct nf_conntrack *nfct)
Create a general __skb_checksum_validate function (actually a macro) to subsume the various checksum_init functions. This function can either init the checksum, or do the full validation (logically checksum_init+skb_check_complete)-- a flag specifies if full vaidation is performed. Also, there is a flag to the function to indicate that zero checksums are allowed (to support optional UDP checksums). Added several stub functions for calling __skb_checksum_validate. Signed-off-by: Tom Herbert <therbert@google.com> --- include/linux/skbuff.h | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+)