Re: [PATCH bpf v2] bpf: Update bpf_{g,s}etsockopt() documentation
From: Ji Rongfeng
Date: Tue Nov 29 2022 - 09:17:30 EST
On 2022/11/27 11:27, Ji Rongfeng wrote:
On 2022/11/24 8:40, Martin KaFai Lau wrote:
On 11/23/22 4:18 PM, Daniel Borkmann wrote:
On 11/18/22 9:18 AM, Ji Rongfeng wrote:
* append missing optnames to the end
* simplify bpf_getsockopt()'s doc
Signed-off-by: Ji Rongfeng <SikoJobs@xxxxxxxxxxx>
---
include/uapi/linux/bpf.h | 20 ++++++++++++--------
tools/include/uapi/linux/bpf.h | 20 ++++++++++++--------
2 files changed, 24 insertions(+), 16 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 51b9aa640ad2..14f29d95ea71 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2576,14 +2576,19 @@ union bpf_attr {
* * **SOL_SOCKET**, which supports the following
*optname*\ s:
* **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
* **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
- * **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
+ * **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**,
+ * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**.
* * **IPPROTO_TCP**, which supports the following
*optname*\ s:
* **TCP_CONGESTION**, **TCP_BPF_IW**,
* **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
* **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
- * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**,
**TCP_NOTSENT_LOWAT**.
+ * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**,
**TCP_NOTSENT_LOWAT**,
+ * **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**,
+ * **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**,
+ * **TCP_BPF_RTO_MIN**.
* * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
- * * **IPPROTO_IPV6**, which supports *optname*
**IPV6_TCLASS**.
+ * * **IPPROTO_IPV6**, which supports the following
*optname*\ s:
+ * **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**.
* Return
* 0 on success, or a negative error in case of failure.
*
@@ -2800,12 +2805,11 @@ union bpf_attr {
* and **BPF_CGROUP_INET6_CONNECT**.
*
* This helper actually implements a subset of
**getsockopt()**.
- * It supports the following *level*\ s:
+ * It supports the same set of *optname*\ s that supported by
nit: that is supported by
+ * **bpf_setsockopt**\ () helper with a few exceptions:
*
- * * **IPPROTO_TCP**, which supports *optname*
- * **TCP_CONGESTION**.
- * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
- * * **IPPROTO_IPV6**, which supports *optname*
**IPV6_TCLASS**.
+ * * **bpf_setsockopt**\ () helper only: **TCP_BPF_***.
+ * * **bpf_getsockopt**\ () helper only: **TCP_SAVED_SYNC**.
I think from a user PoV the above is a bit hard to follow, maybe take
Martin's
earlier feedback into account and add a proper sentence; it will be
much easier
to understand.
+1 Made the change and also fixed TCP_SAVED_SYNC with s/SYNC/SYN/
while applying. Thanks!
Thanks for the helpful reviews. I chose the form of lists was because we
could
append more optnames easily in the future. But I believe it's not late
to apply
that form when we really need it : )
In my opinion, this patch doesn't contain any new feature, but just a
new features
kind of fix
to the documentation, according to the corresponding code in the bpf tree,
which hasn't been modified yet in the bpf-next tree. So I targeted the
former,
as this patch could be useful there. Please let me know if there's any
if there're
customary
rules outside bpf_devel_QA. Thanks!
I just found that SO_BINDTODEVICE is bpf_setsockopt() only. I checked
sock_getbindtodevice() and there's nothing special comparing with
sock_setbindtodevice(), except "down_read(&devnet_rename_sem);" and
"up_read(&devnet_rename_sem);". Martin once wrote:
> The only exception is SO_BINDTODEVICE because it needs to acquire a
> blocking lock. Thus, SO_BINDTODEVICE is not supported.
Were you referring to "down_read(&devnet_rename_sem);"? Seems it's not
acquiring a blocking lock. Maybe "devnet_rename_sem" has been locked for
writing somewhere in bpf before? Please let me know. Thanks!