From: Petar Penkov <ppenkov@xxxxxxxxxx>
Sync updated documentation for bpf_redirect_map.
Sync the bpf_tcp_gen_syncookie helper function definition with the one
in tools/uapi.
Signed-off-by: Petar Penkov <ppenkov@xxxxxxxxxx>
---
tools/include/uapi/linux/bpf.h | 37 +++++++++++++++++++++++++++++++---
1 file changed, 34 insertions(+), 3 deletions(-)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index f506c68b2612..20baee7b2219 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1571,8 +1571,11 @@ union bpf_attr {
* but this is only implemented for native XDP (with driver
* support) as of this writing).
*
- * All values for *flags* are reserved for future usage, and must
- * be left at zero.
+ * The lower two bits of *flags* are used as the return code if
+ * the map lookup fails. This is so that the return value can be
+ * one of the XDP program return codes up to XDP_TX, as chosen by
+ * the caller. Any higher bits in the *flags* argument must be
+ * unset.
*
* When used to redirect packets to net devices, this helper
* provides a high performance increase over **bpf_redirect**\ ().
@@ -2710,6 +2713,33 @@ union bpf_attr {
* **-EPERM** if no permission to send the *sig*.
*
* **-EAGAIN** if bpf program can try again.
+ *
+ * s64 bpf_tcp_gen_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
+ * Description
+ * Try to issue a SYN cookie for the packet with corresponding
+ * IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
+ *
+ * *iph* points to the start of the IPv4 or IPv6 header, while
+ * *iph_len* contains **sizeof**\ (**struct iphdr**) or
+ * **sizeof**\ (**struct ip6hdr**).
+ *
+ * *th* points to the start of the TCP header, while *th_len*
+ * contains the length of the TCP header.
+ *
+ * Return
+ * On success, lower 32 bits hold the generated SYN cookie in
+ * followed by 16 bits which hold the MSS value for that cookie,
+ * and the top 16 bits are unused.
+ *
+ * On failure, the returned value is one of the following:
+ *
+ * **-EINVAL** SYN cookie cannot be issued due to error
+ *
+ * **-ENOENT** SYN cookie should not be issued (no SYN flood)
+ *
+ * **-ENOTSUPP** kernel configuration does not enable SYN cookies
+ *
+ * **-EPROTONOSUPPORT** IP packet version is not 4 or 6
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -2821,7 +2851,8 @@ union bpf_attr {
FN(strtoul), \
FN(sk_storage_get), \
FN(sk_storage_delete), \
- FN(send_signal),
+ FN(send_signal), \
+ FN(tcp_gen_syncookie),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
--
2.22.0.657.g960e92d24f-goog
