From: Aaron Conole <aconole@bytheb•org>
To: netdev@vger•kernel.org
Subject: [PATCH net] af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag
Date: Fri, 18 Sep 2015 12:04:36 -0400 [thread overview]
Message-ID: <f7tvbb7zpbf.fsf@aconole.bos.csb> (raw)
AF_UNIX sockets now return multiple skbs from recv() when MSG_PEEK flag
is set.
This is referenced in kernel bugzilla #12323 @
https://bugzilla.kernel.org/show_bug.cgi?id=12323
As described both in the BZ and lkml thread @
http://lkml.org/lkml/2008/1/8/444 calling recv() with MSG_PEEK on an
AF_UNIX socket only reads a single skb, where the desired effect is
to return as much skb data has been queued, until hitting the recv
buffer size (whichever comes first).
The modified MSG_PEEK path will now move to the next skb in the tree
and jump to the again: label, rather than following the natural loop
structure. This requires duplicating some of the loop head actions.
This was tested using the python socketpair() code attached to the
bugzilla issue.
Signed-off-by: Aaron Conole <aconole@bytheb•org>
---
net/unix/af_unix.c | 17+-
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 03ee4d3..d2fd342 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2179,9 +2181,22 @@ unlock:
if (UNIXCB(skb).fp)
scm.fp = scm_fp_dup(UNIXCB(skb).fp);
- sk_peek_offset_fwd(sk, chunk);
+ if (skip)
+ {
+ sk_peek_offset_fwd(sk, chunk);
+ skip -= chunk;
+ }
- break;
+ if (UNIXCB(skb).fp)
+ break;
+
+ /* XXX - this is ugly; better would be rewrite the function */
+ last = skb;
+ last_len = skb->len;
+ unix_state_lock(&sk);
+ skb = skb_peek_next(skb, &sk->sk_receive_queue);
+ if (skb) goto again;
+ goto unlock;
}
} while (size);
--
1.9.1
next reply other threads:[~2015-09-18 16:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-18 16:04 Aaron Conole [this message]
2015-09-19 17:23 ` [PATCH net] af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag Sergei Shtylyov
2015-09-20 1:55 ` Aaron Conole
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=f7tvbb7zpbf.fsf@aconole.bos.csb \
--to=aconole@bytheb$(echo .)org \
--cc=netdev@vger$(echo .)kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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