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=Ea4JvC3G; 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 B94785A0284 for ; Sun, 29 Jun 2025 19:14:06 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1751217245; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=laEYIKG+VQmNGYSMkaTSoLWbgK7U7LoECe2Sz8FdfDE=; b=Ea4JvC3G1pp4L9/HpVP7CssGuUf9g42IMhM2y5lq2AVFRanWgPdEBIRNsOnrmVIMUmUzH9 UhDxHn93hnkQn2/LXsNBQLjEh4LIDFs61uZl7syPzVgePBljNUe4MojSziJPsODOr4F2ww EjK2JOslEdwx0UEsmExdL0gI+1xSpP8= 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-547-z0r8nSiePwmLl_IIGpSXvg-1; Sun, 29 Jun 2025 13:14:02 -0400 X-MC-Unique: z0r8nSiePwmLl_IIGpSXvg-1 X-Mimecast-MFC-AGG-ID: z0r8nSiePwmLl_IIGpSXvg_1751217241 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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 7F91519373D8; Sun, 29 Jun 2025 17:14:01 +0000 (UTC) Received: from jmaloy-thinkpadp16vgen1.rmtcaqc.csb (unknown [10.22.64.73]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id AE439195609D; Sun, 29 Jun 2025 17:13:59 +0000 (UTC) From: Jon Maloy To: sbrivio@redhat.com, dgibson@redhat.com, david@gibson.dropbear.id.au, jmaloy@redhat.com, passt-dev@passt.top Subject: [PATCH v3 6/8] tap: change signature of function tap_push_l2h() Date: Sun, 29 Jun 2025 13:13:45 -0400 Message-ID: <20250629171348.86323-7-jmaloy@redhat.com> In-Reply-To: <20250629171348.86323-1-jmaloy@redhat.com> References: <20250629171348.86323-1-jmaloy@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ikJyZGLZJ8g9PyFcows2EOFs03oKH5DWATe5uAf-shc_1751217241 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: 6ZHGSJPWA3GU7O5T6E6Y2A2FE3XABP5G X-Message-ID-Hash: 6ZHGSJPWA3GU7O5T6E6Y2A2FE3XABP5G X-MailFrom: jmaloy@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 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: In the following commits it must be possible for the callers of function tap_push_l2h() to specify which source MAC address should be added to the ethernet header sent over the tap interface. As a preparation, we now add a new argument to that function, still without actually using it. Signed-off-by: Jon Maloy --- v3: Improved comment for src_mac argument, as suggested by Stefano. --- tap.c | 18 +++++++++++------- tap.h | 3 ++- tcp.c | 4 ++-- 3 files changed, 15 insertions(+), 10 deletions(-) diff --git a/tap.c b/tap.c index 6db5d88..ceb9d9f 100644 --- a/tap.c +++ b/tap.c @@ -171,17 +171,21 @@ const struct in6_addr *tap_ip6_daddr(const struct ctx *c, * tap_push_l2h() - Build an L2 header for an inbound packet * @c: Execution context * @buf: Buffer address at which to generate header + * @src_mac: MAC address to be used as source for message. NULL means default * @proto: Ethernet protocol number for L3 * * Return: pointer at which to write the packet's payload */ -void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto) +void *tap_push_l2h(const struct ctx *c, void *buf, + const void *src_mac, uint16_t proto) { struct ethhdr *eh = (struct ethhdr *)buf; - /* TODO: ARP table lookup */ memcpy(eh->h_dest, c->guest_mac, ETH_ALEN); - memcpy(eh->h_source, c->our_tap_mac, ETH_ALEN); + if (src_mac) + memcpy(eh->h_source, src_mac, ETH_ALEN); + else + memcpy(eh->h_source, c->our_tap_mac, ETH_ALEN); eh->h_proto = ntohs(proto); return eh + 1; } @@ -261,7 +265,7 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport, { size_t l4len = dlen + sizeof(struct udphdr); char buf[USHRT_MAX]; - struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP); + struct iphdr *ip4h = tap_push_l2h(c, buf, NULL, ETH_P_IP); struct udphdr *uh = tap_push_ip4h(ip4h, src, dst, l4len, IPPROTO_UDP); char *data = tap_push_uh4(uh, src, sport, dst, dport, in, dlen); @@ -281,7 +285,7 @@ void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst, const void *in, size_t l4len) { char buf[USHRT_MAX]; - struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP); + struct iphdr *ip4h = tap_push_l2h(c, buf, NULL, ETH_P_IP); struct icmphdr *icmp4h = tap_push_ip4h(ip4h, src, dst, l4len, IPPROTO_ICMP); @@ -367,7 +371,7 @@ void tap_udp6_send(const struct ctx *c, { size_t l4len = dlen + sizeof(struct udphdr); char buf[USHRT_MAX]; - struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); + struct ipv6hdr *ip6h = tap_push_l2h(c, buf, NULL, ETH_P_IPV6); struct udphdr *uh = tap_push_ip6h(ip6h, src, dst, l4len, IPPROTO_UDP, flow); char *data = tap_push_uh6(uh, src, sport, dst, dport, in, dlen); @@ -389,7 +393,7 @@ void tap_icmp6_send(const struct ctx *c, const void *in, size_t l4len) { char buf[USHRT_MAX]; - struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); + struct ipv6hdr *ip6h = tap_push_l2h(c, buf, NULL, ETH_P_IPV6); struct icmp6hdr *icmp6h = tap_push_ip6h(ip6h, src, dst, l4len, IPPROTO_ICMPV6, 0); diff --git a/tap.h b/tap.h index 6fe3d15..e640d95 100644 --- a/tap.h +++ b/tap.h @@ -70,7 +70,8 @@ static inline void tap_hdr_update(struct tap_hdr *thdr, size_t l2len) } unsigned long tap_l2_max_len(const struct ctx *c); -void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto); +void *tap_push_l2h(const struct ctx *c, void *buf, + const void *src_mac, uint16_t proto); void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src, struct in_addr dst, size_t l4len, uint8_t proto); void *tap_push_uh4(struct udphdr *uh, struct in_addr src, in_port_t sport, diff --git a/tcp.c b/tcp.c index 057ee93..3ecf9e8 100644 --- a/tcp.c +++ b/tcp.c @@ -1898,7 +1898,7 @@ static void tcp_rst_no_conn(const struct ctx *c, int af, return; if (af == AF_INET) { - struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP); + struct iphdr *ip4h = tap_push_l2h(c, buf, NULL, ETH_P_IP); const struct in_addr *rst_src = daddr; const struct in_addr *rst_dst = saddr; @@ -1908,7 +1908,7 @@ static void tcp_rst_no_conn(const struct ctx *c, int af, *rst_src, *rst_dst); } else { - struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); + struct ipv6hdr *ip6h = tap_push_l2h(c, buf, NULL, ETH_P_IPV6); const struct in6_addr *rst_src = daddr; const struct in6_addr *rst_dst = saddr; -- 2.48.1