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=EypNr319; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTPS id 475795A0272 for ; Mon, 09 Mar 2026 10:48:01 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773049680; 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=afXwiyIVl+pNtBNQpy9OR7nf2uQw0k4hXpftsNSv3O0=; b=EypNr319reQ8Icb/A0nv26Q/wm8qgJsilRfhSrrypDdWPAWsLASKuKO+v7nLQIXDLhDVKM XR+MiG3z+tZBnSDpKkginy1otZ6HOQbq4/2H1sn+SapIi52ghhULGesvoY+tTUnC42MAYE JcWU7MT22bPOxt6e5WgTFfWydp0xtXo= Received: from mx-prod-mc-03.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-644-5S3vMq4COiSwd12qnDOFKw-1; Mon, 09 Mar 2026 05:47:58 -0400 X-MC-Unique: 5S3vMq4COiSwd12qnDOFKw-1 X-Mimecast-MFC-AGG-ID: 5S3vMq4COiSwd12qnDOFKw_1773049677 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 92CBC1956050 for ; Mon, 9 Mar 2026 09:47:57 +0000 (UTC) Received: from lenovo-t14s.redhat.com (unknown [10.45.226.4]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 98FB51954102; Mon, 9 Mar 2026 09:47:56 +0000 (UTC) From: Laurent Vivier To: passt-dev@passt.top Subject: [PATCH v2 07/13] udp: Pass iov_tail to udp_update_hdr4()/udp_update_hdr6() Date: Mon, 9 Mar 2026 10:47:38 +0100 Message-ID: <20260309094744.1907754-8-lvivier@redhat.com> In-Reply-To: <20260309094744.1907754-1-lvivier@redhat.com> References: <20260309094744.1907754-1-lvivier@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: sgI62kLGx0xpP_pfjiWUVtR3zHR-WeTna2N4CTXknHU_1773049677 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: CCENT6JG6P6C5DOY24TFOUOAJ3PHTETZ X-Message-ID-Hash: CCENT6JG6P6C5DOY24TFOUOAJ3PHTETZ 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: Change udp_update_hdr4() and udp_update_hdr6() to take a separate struct udphdr pointer and an iov_tail for the payload, instead of a struct udp_payload_t pointer and an explicit data length. This decouples the header update functions from the udp_payload_t memory layout, which assumes all headers and data sit in a single contiguous buffer. The vhost-user path uses virtqueue-provided scatter-gather buffers where this assumption does not hold; passing an iov_tail lets both the tap path and the vhost-user path share the same functions without casting through layout-specific helpers. Signed-off-by: Laurent Vivier --- udp.c | 72 +++++++++++++++++++++++--------------------------- udp_internal.h | 10 ++++--- udp_vu.c | 14 ++++++++-- 3 files changed, 51 insertions(+), 45 deletions(-) diff --git a/udp.c b/udp.c index 464aa09365cc..6840e8843e68 100644 --- a/udp.c +++ b/udp.c @@ -255,20 +255,20 @@ static void udp_iov_init(const struct ctx *c) /** * udp_update_hdr4() - Update headers for one IPv4 datagram * @ip4h: Pre-filled IPv4 header (except for tot_len and saddr) - * @bp: Pointer to udp_payload_t to update + * @uh: UDP header to update + * @payload: UDP payload * @toside: Flowside for destination side - * @dlen: Length of UDP payload * @no_udp_csum: Do not set UDP checksum * * Return: size of IPv4 payload (UDP header + data) */ -size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp, - const struct flowside *toside, size_t dlen, - bool no_udp_csum) +size_t udp_update_hdr4(struct iphdr *ip4h, struct udphdr *uh, + struct iov_tail *payload, + const struct flowside *toside, bool no_udp_csum) { const struct in_addr *src = inany_v4(&toside->oaddr); const struct in_addr *dst = inany_v4(&toside->eaddr); - size_t l4len = dlen + sizeof(bp->uh); + size_t l4len = iov_tail_size(payload) + sizeof(*uh); size_t l3len = l4len + sizeof(*ip4h); ASSERT(src && dst); @@ -278,19 +278,13 @@ size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp, ip4h->saddr = src->s_addr; ip4h->check = csum_ip4_header(l3len, IPPROTO_UDP, *src, *dst); - bp->uh.source = htons(toside->oport); - bp->uh.dest = htons(toside->eport); - bp->uh.len = htons(l4len); - if (no_udp_csum) { - bp->uh.check = 0; - } else { - const struct iovec iov = { - .iov_base = bp->data, - .iov_len = dlen - }; - struct iov_tail data = IOV_TAIL(&iov, 1, 0); - csum_udp4(&bp->uh, *src, *dst, &data); - } + uh->source = htons(toside->oport); + uh->dest = htons(toside->eport); + uh->len = htons(l4len); + if (no_udp_csum) + uh->check = 0; + else + csum_udp4(uh, *src, *dst, payload); return l4len; } @@ -299,18 +293,18 @@ size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp, * udp_update_hdr6() - Update headers for one IPv6 datagram * @ip6h: Pre-filled IPv6 header (except for payload_len and * addresses) - * @bp: Pointer to udp_payload_t to update + * @uh: UDP header to update + * @payload: UDP payload * @toside: Flowside for destination side - * @dlen: Length of UDP payload * @no_udp_csum: Do not set UDP checksum * * Return: size of IPv6 payload (UDP header + data) */ -size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp, - const struct flowside *toside, size_t dlen, - bool no_udp_csum) +size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udphdr *uh, + struct iov_tail *payload, + const struct flowside *toside, bool no_udp_csum) { - uint16_t l4len = dlen + sizeof(bp->uh); + uint16_t l4len = iov_tail_size(payload) + sizeof(*uh); ip6h->payload_len = htons(l4len); ip6h->daddr = toside->eaddr.a6; @@ -319,22 +313,17 @@ size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp, ip6h->nexthdr = IPPROTO_UDP; ip6h->hop_limit = 255; - bp->uh.source = htons(toside->oport); - bp->uh.dest = htons(toside->eport); - bp->uh.len = ip6h->payload_len; + uh->source = htons(toside->oport); + uh->dest = htons(toside->eport); + uh->len = ip6h->payload_len; if (no_udp_csum) { /* 0 is an invalid checksum for UDP IPv6 and dropped by * the kernel stack, even if the checksum is disabled by virtio * flags. We need to put any non-zero value here. */ - bp->uh.check = 0xffff; + uh->check = 0xffff; } else { - const struct iovec iov = { - .iov_base = bp->data, - .iov_len = dlen - }; - struct iov_tail data = IOV_TAIL(&iov, 1, 0); - csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, &data); + csum_udp6(uh, &toside->oaddr.a6, &toside->eaddr.a6, payload); } return l4len; @@ -374,12 +363,17 @@ static void udp_tap_prepare(const struct mmsghdr *mmh, struct ethhdr *eh = (*tap_iov)[UDP_IOV_ETH].iov_base; struct udp_payload_t *bp = &udp_payload[idx]; struct udp_meta_t *bm = &udp_meta[idx]; + const struct iovec iov = { + .iov_base = bp->data, + .iov_len = mmh[idx].msg_len, + }; + struct iov_tail payload = IOV_TAIL(&iov, 1, 0); size_t l4len, l2len; eth_update_mac(eh, NULL, tap_omac); if (!inany_v4(&toside->eaddr) || !inany_v4(&toside->oaddr)) { - l4len = udp_update_hdr6(&bm->ip6h, bp, toside, - mmh[idx].msg_len, no_udp_csum); + l4len = udp_update_hdr6(&bm->ip6h, &bp->uh, &payload, toside, + no_udp_csum); l2len = MAX(l4len + sizeof(bm->ip6h) + ETH_HLEN, ETH_ZLEN); tap_hdr_update(&bm->taph, l2len); @@ -387,8 +381,8 @@ static void udp_tap_prepare(const struct mmsghdr *mmh, eh->h_proto = htons_constant(ETH_P_IPV6); (*tap_iov)[UDP_IOV_IP] = IOV_OF_LVALUE(bm->ip6h); } else { - l4len = udp_update_hdr4(&bm->ip4h, bp, toside, - mmh[idx].msg_len, no_udp_csum); + l4len = udp_update_hdr4(&bm->ip4h, &bp->uh, &payload, toside, + no_udp_csum); l2len = MAX(l4len + sizeof(bm->ip4h) + ETH_HLEN, ETH_ZLEN); tap_hdr_update(&bm->taph, l2len); diff --git a/udp_internal.h b/udp_internal.h index 64e457748324..fba5ef33cf99 100644 --- a/udp_internal.h +++ b/udp_internal.h @@ -25,11 +25,13 @@ struct udp_payload_t { } __attribute__ ((packed, aligned(__alignof__(unsigned int)))); #endif -size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp, - const struct flowside *toside, size_t dlen, +size_t udp_update_hdr4(struct iphdr *ip4h, struct udphdr *uh, + struct iov_tail *payload, + const struct flowside *toside, bool no_udp_csum); -size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp, - const struct flowside *toside, size_t dlen, +size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udphdr *uh, + struct iov_tail *payload, + const struct flowside *toside, bool no_udp_csum); void udp_sock_fwd(const struct ctx *c, int s, int rule_hint, uint8_t frompif, in_port_t port, const struct timespec *now); diff --git a/udp_vu.c b/udp_vu.c index 27ae93de4420..2a5d3f822bf6 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -122,21 +122,31 @@ static size_t udp_vu_prepare(const struct ctx *c, const struct iov_tail *data, if (inany_v4(&toside->eaddr) && inany_v4(&toside->oaddr)) { struct iphdr *iph = vu_ip(iov[0].iov_base); struct udp_payload_t *bp = vu_payloadv4(iov[0].iov_base); + const struct iovec payload_iov = { + .iov_base = bp->data, + .iov_len = dlen, + }; + struct iov_tail payload = IOV_TAIL(&payload_iov, 1, 0); eh->h_proto = htons(ETH_P_IP); *iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_UDP); - l4len = udp_update_hdr4(iph, bp, toside, dlen, true); + l4len = udp_update_hdr4(iph, &bp->uh, &payload, toside, true); } else { struct ipv6hdr *ip6h = vu_ip(iov[0].iov_base); struct udp_payload_t *bp = vu_payloadv6(iov[0].iov_base); + const struct iovec payload_iov = { + .iov_base = bp->data, + .iov_len = dlen, + }; + struct iov_tail payload = IOV_TAIL(&payload_iov, 1, 0); eh->h_proto = htons(ETH_P_IPV6); *ip6h = (struct ipv6hdr)L2_BUF_IP6_INIT(IPPROTO_UDP); - l4len = udp_update_hdr6(ip6h, bp, toside, dlen, true); + l4len = udp_update_hdr6(ip6h, &bp->uh, &payload, toside, true); } return l4len; -- 2.53.0