From: Jakub Kicinski <kuba@kernel.org>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com,
jiri@resnulli.us, donald.hunter@gmail.com,
Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH net-next 2/4] tools: ynl: allow setting recv() size
Date: Fri, 1 Mar 2024 15:05:40 -0800 [thread overview]
Message-ID: <20240301230542.116823-3-kuba@kernel.org> (raw)
In-Reply-To: <20240301230542.116823-1-kuba@kernel.org>
Make the size of the buffer we use for recv() configurable.
The details of the buffer sizing in netlink are somewhat
arcane, we could spend a lot of time polishing this API.
Let's just leave some hopefully helpful comments for now.
This is a for-developers-only feature, anyway.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
tools/net/ynl/lib/ynl.py | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/tools/net/ynl/lib/ynl.py b/tools/net/ynl/lib/ynl.py
index 92ade9105f31..bc5a526dbb99 100644
--- a/tools/net/ynl/lib/ynl.py
+++ b/tools/net/ynl/lib/ynl.py
@@ -84,6 +84,10 @@ from .nlspec import SpecFamily
return f"Netlink error: {os.strerror(-self.nl_msg.error)}\n{self.nl_msg}"
+class ConfigError(Exception):
+ pass
+
+
class NlAttr:
ScalarFormat = namedtuple('ScalarFormat', ['native', 'big', 'little'])
type_formats = {
@@ -400,7 +404,8 @@ genl_family_name_to_id = None
class YnlFamily(SpecFamily):
- def __init__(self, def_path, schema=None, process_unknown=False):
+ def __init__(self, def_path, schema=None, process_unknown=False,
+ recv_size=131072):
super().__init__(def_path, schema)
self.include_raw = False
@@ -423,6 +428,16 @@ genl_family_name_to_id = None
self.async_msg_ids = set()
self.async_msg_queue = []
+ # Note that netlink will use conservative (min) message size for
+ # the first dump recv() on the socket, our setting will only matter
+ # from the second recv() on.
+ self._recv_size = recv_size
+ # Netlink will always allocate at least PAGE_SIZE - sizeof(skb_shinfo)
+ # for a message, so smaller receive sizes will lead to truncation.
+ # Note that the min size for other families may be larger than 4k!
+ if self._recv_size < 4000:
+ raise ConfigError()
+
for msg in self.msgs.values():
if msg.is_async:
self.async_msg_ids.add(msg.rsp_value)
@@ -799,7 +814,7 @@ genl_family_name_to_id = None
def check_ntf(self):
while True:
try:
- reply = self.sock.recv(128 * 1024, socket.MSG_DONTWAIT)
+ reply = self.sock.recv(self._recv_size, socket.MSG_DONTWAIT)
except BlockingIOError:
return
@@ -854,7 +869,7 @@ genl_family_name_to_id = None
done = False
rsp = []
while not done:
- reply = self.sock.recv(128 * 1024)
+ reply = self.sock.recv(self._recv_size)
nms = NlMsgs(reply, attr_space=op.attr_set)
for nl_msg in nms:
if nl_msg.extack:
--
2.44.0
next prev parent reply other threads:[~2024-03-01 23:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-01 23:05 [PATCH net-next 0/4] tools: ynl: add --dbg-small-recv for easier kernel testing Jakub Kicinski
2024-03-01 23:05 ` [PATCH net-next 1/4] tools: ynl: move the new line in NlMsg __repr__ Jakub Kicinski
2024-03-04 11:08 ` Donald Hunter
2024-03-01 23:05 ` Jakub Kicinski [this message]
2024-03-04 11:38 ` [PATCH net-next 2/4] tools: ynl: allow setting recv() size Donald Hunter
2024-03-04 13:38 ` Donald Hunter
2024-03-04 14:58 ` Jakub Kicinski
2024-03-04 15:57 ` Donald Hunter
2024-03-04 16:20 ` Jakub Kicinski
2024-03-01 23:05 ` [PATCH net-next 3/4] tools: ynl: support debug printing messages Jakub Kicinski
2024-03-04 11:34 ` Donald Hunter
2024-03-01 23:05 ` [PATCH net-next 4/4] tools: ynl: add --dbg-small-recv for easier kernel testing Jakub Kicinski
2024-03-04 11:26 ` Donald Hunter
2024-03-04 14:59 ` Jakub Kicinski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240301230542.116823-3-kuba@kernel.org \
--to=kuba@kernel.org \
--cc=davem@davemloft.net \
--cc=donald.hunter@gmail.com \
--cc=edumazet@google.com \
--cc=jiri@resnulli.us \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).