From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=PoeV3Btb; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTPS id C247C5A026F for ; Wed, 02 Apr 2025 19:23:50 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1743614629; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d7j6CO2YG9Kc0TmocdZsiew5743EGmEHTruI5rgQrQI=; b=PoeV3Btbhid/PETX+i/CoaWUUe8ru5917D6qgCMhfeoUEdsySOVwQ0lzr/bKu/j8FHp760 U661l3QjWVid1ZVu0OmP1vxSLnFg9KTYOqsndWdPq+JsNrX2ezVo/XkGSwpzGjUR2+blsz zpajIrigfomFe3LhvKj5SsWimnBczno= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-83-dBebqequPgCzfOIGszXDPg-1; Wed, 02 Apr 2025 13:23:48 -0400 X-MC-Unique: dBebqequPgCzfOIGszXDPg-1 X-Mimecast-MFC-AGG-ID: dBebqequPgCzfOIGszXDPg_1743614627 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 572C5195608F for ; Wed, 2 Apr 2025 17:23:47 +0000 (UTC) Received: from lenovo-t14s.redhat.com (unknown [10.44.33.101]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 2A39B19560AD; Wed, 2 Apr 2025 17:23:45 +0000 (UTC) From: Laurent Vivier To: passt-dev@passt.top Subject: [PATCH 01/18] arp: Don't mix incoming and outgoing buffers Date: Wed, 2 Apr 2025 19:23:26 +0200 Message-ID: <20250402172343.858187-2-lvivier@redhat.com> In-Reply-To: <20250402172343.858187-1-lvivier@redhat.com> References: <20250402172343.858187-1-lvivier@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: zJt8undxbi6WVbTYQ2Ey16NbPNP7f4IM1XB6qv9Q0to_1743614627 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: TJEQZ7OA4GSDYJACYRURBIPX4CX5WOBG X-Message-ID-Hash: TJEQZ7OA4GSDYJACYRURBIPX4CX5WOBG X-MailFrom: lvivier@redhat.com 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: Laurent Vivier X-Mailman-Version: 3.3.8 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: Don't use the memory of the incoming packet to build the outgoing buffer as it can be memory of the TX queue in the case of vhost-user. Moreover with vhost-user, the packet can be splitted accross several iovec and it's easier to rebuild it in a buffer than updating an existing iovec array. Signed-off-by: Laurent Vivier --- arp.c | 84 ++++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 55 insertions(+), 29 deletions(-) diff --git a/arp.c b/arp.c index fc482bbd9938..9d68d7c3b602 100644 --- a/arp.c +++ b/arp.c @@ -31,56 +31,82 @@ #include "tap.h" /** - * arp() - Check if this is a supported ARP message, reply as needed + * ignore_arp() - Check if this is a supported ARP message * @c: Execution context - * @p: Packet pool, single packet with Ethernet buffer + * @ah: ARP header + * @am: ARP message * - * Return: 1 if handled, -1 on failure + * Return: true if the message is supported, false otherwise. */ -int arp(const struct ctx *c, const struct pool *p) +static bool ignore_arp(const struct ctx *c, + const struct arphdr *ah, const struct arpmsg *am) { - unsigned char swap[4]; - struct ethhdr *eh; - struct arphdr *ah; - struct arpmsg *am; - size_t l2len; - - eh = packet_get(p, 0, 0, sizeof(*eh), NULL); - ah = packet_get(p, 0, sizeof(*eh), sizeof(*ah), NULL); - am = packet_get(p, 0, sizeof(*eh) + sizeof(*ah), sizeof(*am), NULL); - - if (!eh || !ah || !am) - return -1; - if (ah->ar_hrd != htons(ARPHRD_ETHER) || ah->ar_pro != htons(ETH_P_IP) || ah->ar_hln != ETH_ALEN || ah->ar_pln != 4 || ah->ar_op != htons(ARPOP_REQUEST)) - return 1; + return true; /* Discard announcements, but not 0.0.0.0 "probes" */ if (memcmp(am->sip, &in4addr_any, sizeof(am->sip)) && !memcmp(am->sip, am->tip, sizeof(am->sip))) - return 1; + return true; /* Don't resolve the guest's assigned address, either. */ if (!memcmp(am->tip, &c->ip4.addr, sizeof(am->tip))) + return true; + + return false; +} + +/** + * arp() - Check if this is a supported ARP message, reply as needed + * @c: Execution context + * @p: Packet pool, single packet with Ethernet buffer + * + * Return: 1 if handled, -1 on failure + */ +int arp(const struct ctx *c, const struct pool *p) +{ + struct { + struct ethhdr eh; + struct arphdr ah; + struct arpmsg am; + } __attribute__((__packed__)) resp; + const struct ethhdr *eh; + const struct arphdr *ah; + const struct arpmsg *am; + + eh = packet_get(p, 0, 0, sizeof(*eh), NULL); + ah = packet_get(p, 0, sizeof(*eh), sizeof(*ah), NULL); + am = packet_get(p, 0, sizeof(*eh) + sizeof(*ah), sizeof(*am), NULL); + + if (!eh || !ah || !am) + return -1; + + if (ignore_arp(c, ah, am)) return 1; - ah->ar_op = htons(ARPOP_REPLY); - memcpy(am->tha, am->sha, sizeof(am->tha)); - memcpy(am->sha, c->our_tap_mac, sizeof(am->sha)); + /* ethernet header */ + resp.eh.h_proto = htons(ETH_P_ARP); + memcpy(resp.eh.h_dest, eh->h_source, sizeof(resp.eh.h_dest)); + memcpy(resp.eh.h_source, c->our_tap_mac, sizeof(resp.eh.h_source)); - memcpy(swap, am->tip, sizeof(am->tip)); - memcpy(am->tip, am->sip, sizeof(am->tip)); - memcpy(am->sip, swap, sizeof(am->sip)); + /* ARP header */ + resp.ah.ar_op = htons(ARPOP_REPLY); + resp.ah.ar_hrd = ah->ar_hrd; + resp.ah.ar_pro = ah->ar_pro; + resp.ah.ar_hln = ah->ar_hln; + resp.ah.ar_pln = ah->ar_pln; - l2len = sizeof(*eh) + sizeof(*ah) + sizeof(*am); - memcpy(eh->h_dest, eh->h_source, sizeof(eh->h_dest)); - memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source)); + /* ARP message */ + memcpy(resp.am.sha, c->our_tap_mac, sizeof(resp.am.sha)); + memcpy(resp.am.sip, am->tip, sizeof(resp.am.sip)); + memcpy(resp.am.tha, am->sha, sizeof(resp.am.tha)); + memcpy(resp.am.tip, am->sip, sizeof(resp.am.tip)); - tap_send_single(c, eh, l2len); + tap_send_single(c, &resp, sizeof(resp)); return 1; } -- 2.49.0