From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 8469B5A0268 for ; Fri, 6 Jan 2023 01:43:30 +0100 (CET) Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4Np4ML5m5Hz4xwl; Fri, 6 Jan 2023 11:43:26 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=201602; t=1672965806; bh=8910+GKI0MgwzR85voXOHdYLCB7x8t7qRQ0n2Y0z7nY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pt1FtoatwUOnWCzZQ/YEd0KPL7YswbCYjdRCnm9sQpPIrhEdZPoW4X9E0OJ+yjwX1 u7jLYulcEzangVldsdbFJp0osorG71aOXqSzbFfy3zmXstAZp/KYB+orsk8SzXs9v3 noVeS0bpaxEOZA/Q08FXxpotORySA16XVTPOqn7E= From: David Gibson To: Stefano Brivio , passt-dev@passt.top Subject: [PATCH v3 01/18] pcap: Introduce pcap_frame() helper Date: Fri, 6 Jan 2023 11:43:05 +1100 Message-Id: <20230106004322.985665-2-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230106004322.985665-1-david@gibson.dropbear.id.au> References: <20230106004322.985665-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: 2TSUAVZA27VKNWG52AINIXFPAVNTET2C X-Message-ID-Hash: 2TSUAVZA27VKNWG52AINIXFPAVNTET2C X-MailFrom: dgibson@gandalf.ozlabs.org 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: pcap(), pcapm() and pcapmm() duplicate some code, for the actual writing to the capture file. The purpose of pcapm() and pcapmm() not calling pcap() seems to be to avoid repeatedly calling gettimeofday() and to avoid printing errors for every packet in a batch if there's a problem. We can accomplish that while still sharing code by adding a new helper which takes the packet timestamp as a parameter. Signed-off-by: David Gibson --- pcap.c | 76 +++++++++++++++++++++++++++++----------------------------- 1 file changed, 38 insertions(+), 38 deletions(-) diff --git a/pcap.c b/pcap.c index 836688d..0c6dc89 100644 --- a/pcap.c +++ b/pcap.c @@ -65,6 +65,28 @@ struct pcap_pkthdr { uint32_t len; }; +/** + * pcap_frame() - Capture a single frame to pcap file with given timestamp + * @pkt: Pointer to data buffer, including L2 headers + * @len: L2 packet length + * @tv: Timestamp + * + * Returns: 0 on success, -errno on error writing to the file + */ +static int pcap_frame(const char *pkt, size_t len, const struct timeval *tv) +{ + struct pcap_pkthdr h; + + h.tv_sec = tv->tv_sec; + h.tv_usec = tv->tv_usec; + h.caplen = h.len = len; + + if (write(pcap_fd, &h, sizeof(h)) < 0 || write(pcap_fd, pkt, len) < 0) + return -errno; + + return 0; +} + /** * pcap() - Capture a single frame to pcap file * @pkt: Pointer to data buffer, including L2 headers @@ -72,18 +94,13 @@ struct pcap_pkthdr { */ void pcap(const char *pkt, size_t len) { - struct pcap_pkthdr h; struct timeval tv; if (pcap_fd == -1) return; gettimeofday(&tv, NULL); - h.tv_sec = tv.tv_sec; - h.tv_usec = tv.tv_usec; - h.caplen = h.len = len; - - if (write(pcap_fd, &h, sizeof(h)) < 0 || write(pcap_fd, pkt, len) < 0) + if (pcap_frame(pkt, len, &tv) != 0) debug("Cannot log packet, length %lu", len); } @@ -93,8 +110,6 @@ void pcap(const char *pkt, size_t len) */ void pcapm(const struct msghdr *mh) { - struct pcap_pkthdr h; - struct iovec *iov; struct timeval tv; unsigned int i; @@ -102,24 +117,17 @@ void pcapm(const struct msghdr *mh) return; gettimeofday(&tv, NULL); - h.tv_sec = tv.tv_sec; - h.tv_usec = tv.tv_usec; for (i = 0; i < mh->msg_iovlen; i++) { - iov = &mh->msg_iov[i]; + const struct iovec *iov = &mh->msg_iov[i]; - h.caplen = h.len = iov->iov_len - 4; - - if (write(pcap_fd, &h, sizeof(h)) < 0) - goto fail; - if (write(pcap_fd, (char *)iov->iov_base + 4, - iov->iov_len - 4) < 0) - goto fail; + if (pcap_frame((char *)iov->iov_base + 4, + iov->iov_len - 4, &tv) != 0) { + debug("Cannot log packet, length %lu", + iov->iov_len - 4); + return; + } } - - return; -fail: - debug("Cannot log packet, length %lu", iov->iov_len - 4); } /** @@ -128,8 +136,6 @@ fail: */ void pcapmm(const struct mmsghdr *mmh, unsigned int vlen) { - struct pcap_pkthdr h; - struct iovec *iov; struct timeval tv; unsigned int i, j; @@ -137,27 +143,21 @@ void pcapmm(const struct mmsghdr *mmh, unsigned int vlen) return; gettimeofday(&tv, NULL); - h.tv_sec = tv.tv_sec; - h.tv_usec = tv.tv_usec; for (i = 0; i < vlen; i++) { const struct msghdr *mh = &mmh[i].msg_hdr; for (j = 0; j < mh->msg_iovlen; j++) { - iov = &mh->msg_iov[j]; - - h.caplen = h.len = iov->iov_len - 4; - - if (write(pcap_fd, &h, sizeof(h)) < 0) - goto fail; - if (write(pcap_fd, (char *)iov->iov_base + 4, - iov->iov_len - 4) < 0) - goto fail; + const struct iovec *iov = &mh->msg_iov[j]; + + if (pcap_frame((char *)iov->iov_base + 4, + iov->iov_len - 4, &tv) != 0) { + debug("Cannot log packet, length %lu", + iov->iov_len - 4); + return; + } } } - return; -fail: - debug("Cannot log packet, length %lu", iov->iov_len - 4); } /** -- 2.39.0