From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by passt.top (Postfix, from userid 1000) id C950D5A0268; Wed, 16 Nov 2022 14:53:26 +0100 (CET) From: Stefano Brivio To: passt-dev@passt.top Subject: [PATCH] tap: Revert recently added checks in tap_handler_passt() Date: Wed, 16 Nov 2022 14:53:26 +0100 Message-Id: <20221116135326.247953-1-sbrivio@redhat.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: BKMADUQ2G23MKHAQ3H7IEO3SOPCGZ5TX X-Message-ID-Hash: BKMADUQ2G23MKHAQ3H7IEO3SOPCGZ5TX X-MailFrom: sbrivio@passt.top X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.3 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: This reverts commit 198f87835dc4 ("tap: Return -EIO from tap_handler_passt() on inconsistent packet stream") and commit 510dace86ccf ("tap: Keep stream consistent if qemu length descriptor spans two recv() calls"). I can hit occasional failures in perf/passt_tcp tests where we seem to be getting excess data at the end of a recv(), and for some reason I couldn't figure out yet, if we just ignore it, subsequent recv() calls from qemu return correct data. If we close the connection, qemu can't talk to us anymore, of course. Signed-off-by: Stefano Brivio --- tap.c | 20 ++++---------------- 1 file changed, 4 insertions(+), 16 deletions(-) diff --git a/tap.c b/tap.c index b7ac996..d26af58 100644 --- a/tap.c +++ b/tap.c @@ -747,31 +747,19 @@ redo: return -ECONNRESET; } - while (n > 0) { - ssize_t len; - - /* Force receiving at least a complete length descriptor to - * avoid an inconsistent stream. - */ - if (n < (ssize_t)sizeof(uint32_t)) { - rem = recv(c->fd_tap, p + n, - (ssize_t)sizeof(uint32_t) - n, 0); - if ((n += rem) != (ssize_t)sizeof(uint32_t)) - return -EIO; - } - - len = ntohl(*(uint32_t *)p); + while (n > (ssize_t)sizeof(uint32_t)) { + ssize_t len = ntohl(*(uint32_t *)p); p += sizeof(uint32_t); n -= sizeof(uint32_t); /* At most one packet might not fit in a single read, and this - * also needs to be blocking. + * needs to be blocking. */ if (len > n) { rem = recv(c->fd_tap, p + n, len - n, 0); if ((n += rem) != len) - return -EIO; + return 0; } /* Complete the partial read above before discarding a malformed -- 2.35.1