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From: Jon Maloy <jmaloy@redhat.com>
To: sbrivio@redhat.com, dgibson@redhat.com,
	david@gibson.dropbear.id.au, jmaloy@redhat.com,
	passt-dev@passt.top
Subject: [PATCH v4 8/9] icmp: let icmp use mac address from flowside structure
Date: Tue, 19 Aug 2025 23:10:04 -0400	[thread overview]
Message-ID: <20250820031005.2725591-9-jmaloy@redhat.com> (raw)
In-Reply-To: <20250820031005.2725591-1-jmaloy@redhat.com>

Even ICMP needs to be updated to use the external MAC address instead
of just the own tap address when applicable. We do that here.

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 icmp.c |  4 ++--
 ndp.c  |  2 +-
 tap.c  | 10 ++++++----
 tap.h  |  4 ++--
 udp.c  | 12 ++++++++----
 5 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/icmp.c b/icmp.c
index 95f38c1..aa42cc3 100644
--- a/icmp.c
+++ b/icmp.c
@@ -129,12 +129,12 @@ void icmp_sock_handler(const struct ctx *c, union epoll_ref ref)
 		const struct in_addr *daddr = inany_v4(&ini->eaddr);
 
 		ASSERT(saddr && daddr); /* Must have IPv4 addresses */
-		tap_icmp4_send(c, *saddr, *daddr, buf, n);
+		tap_icmp4_send(c, *saddr, *daddr, buf, pingf->f.tap_omac, n);
 	} else if (pingf->f.type == FLOW_PING6) {
 		const struct in6_addr *saddr = &ini->oaddr.a6;
 		const struct in6_addr *daddr = &ini->eaddr.a6;
 
-		tap_icmp6_send(c, saddr, daddr, buf, n);
+		tap_icmp6_send(c, saddr, daddr, buf, pingf->f.tap_omac, n);
 	}
 	return;
 
diff --git a/ndp.c b/ndp.c
index 9912f80..19b9b28 100644
--- a/ndp.c
+++ b/ndp.c
@@ -185,7 +185,7 @@ static void ndp_send(const struct ctx *c, const struct in6_addr *dst,
 {
 	const struct in6_addr *src = &c->ip6.our_tap_ll;
 
-	tap_icmp6_send(c, src, dst, buf, l4len);
+	tap_icmp6_send(c, src, dst, buf, c->our_tap_mac, l4len);
 }
 
 /**
diff --git a/tap.c b/tap.c
index 0349835..443928a 100644
--- a/tap.c
+++ b/tap.c
@@ -278,13 +278,14 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
  * @src:	IPv4 source address
  * @dst:	IPv4 destination address
  * @in:		ICMP packet, including ICMP header
+ * @src_mac:	MAC address to be used as source for message
  * @l4len:	ICMP packet length, including ICMP header
  */
 void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst,
-		    const void *in, size_t l4len)
+		    const void *in, const void *src_mac, size_t l4len)
 {
 	char buf[USHRT_MAX];
-	struct iphdr *ip4h = tap_push_l2h(c, buf, NULL, ETH_P_IP);
+	struct iphdr *ip4h = tap_push_l2h(c, buf, src_mac, ETH_P_IP);
 	struct icmphdr *icmp4h = tap_push_ip4h(ip4h, src, dst,
 					       l4len, IPPROTO_ICMP);
 
@@ -385,14 +386,15 @@ void tap_udp6_send(const struct ctx *c,
  * @src:	IPv6 source address
  * @dst:	IPv6 destination address
  * @in:		ICMP packet, including ICMP header
+ * @src_mac:	MAC address to be used as source for message
  * @l4len:	ICMP packet length, including ICMP header
  */
 void tap_icmp6_send(const struct ctx *c,
 		    const struct in6_addr *src, const struct in6_addr *dst,
-		    const void *in, size_t l4len)
+		    const void *in, const void *src_mac, size_t l4len)
 {
 	char buf[USHRT_MAX];
-	struct ipv6hdr *ip6h = tap_push_l2h(c, buf, NULL, ETH_P_IPV6);
+	struct ipv6hdr *ip6h = tap_push_l2h(c, buf, src_mac, 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 6ec171d..ce0b9a6 100644
--- a/tap.h
+++ b/tap.h
@@ -91,7 +91,7 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
 		   struct in_addr dst, in_port_t dport,
 		   const void *in, size_t dlen);
 void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst,
-		    const void *in, size_t l4len);
+		    const void *in, const void *src_mac, size_t l4len);
 const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
 				     const struct in6_addr *src);
 void *tap_push_ip6h(struct ipv6hdr *ip6h,
@@ -103,7 +103,7 @@ void tap_udp6_send(const struct ctx *c,
 		   uint32_t flow, void *in, size_t dlen);
 void tap_icmp6_send(const struct ctx *c,
 		    const struct in6_addr *src, const struct in6_addr *dst,
-		    const void *in, size_t l4len);
+		    const void *in, const void *src_mac, size_t l4len);
 void tap_send_single(const struct ctx *c, const void *data, size_t l2len);
 size_t tap_send_frames(const struct ctx *c, const struct iovec *iov,
 		       size_t bufs_per_frame, size_t nframes);
diff --git a/udp.c b/udp.c
index 30937dd..8d43646 100644
--- a/udp.c
+++ b/udp.c
@@ -385,6 +385,7 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
  * udp_send_tap_icmp4() - Construct and send ICMPv4 to local peer
  * @c:		Execution context
  * @ee:	Extended error descriptor
+ * @uflow:	UDP flow
  * @toside:	Destination side of flow
  * @saddr:	Address of ICMP generating node
  * @in:	First bytes (max 8) of original UDP message body
@@ -392,6 +393,7 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
  */
 static void udp_send_tap_icmp4(const struct ctx *c,
 			       const struct sock_extended_err *ee,
+			       const struct udp_flow *uflow,
 			       const struct flowside *toside,
 			       struct in_addr saddr,
 			       const void *in, size_t dlen)
@@ -421,7 +423,7 @@ static void udp_send_tap_icmp4(const struct ctx *c,
 	tap_push_uh4(&msg.uh, eaddr, eport, oaddr, oport, in, dlen);
 	memcpy(&msg.data, in, dlen);
 
-	tap_icmp4_send(c, saddr, eaddr, &msg, msglen);
+	tap_icmp4_send(c, saddr, eaddr, &msg, uflow->f.tap_omac, msglen);
 }
 
 
@@ -429,6 +431,7 @@ static void udp_send_tap_icmp4(const struct ctx *c,
  * udp_send_tap_icmp6() - Construct and send ICMPv6 to local peer
  * @c:		Execution context
  * @ee:	Extended error descriptor
+ * @uflow:	UDP flow
  * @toside:	Destination side of flow
  * @saddr:	Address of ICMP generating node
  * @in:	First bytes (max 1232) of original UDP message body
@@ -437,6 +440,7 @@ static void udp_send_tap_icmp4(const struct ctx *c,
  */
 static void udp_send_tap_icmp6(const struct ctx *c,
 			       const struct sock_extended_err *ee,
+			       const struct udp_flow *uflow,
 			       const struct flowside *toside,
 			       const struct in6_addr *saddr,
 			       void *in, size_t dlen, uint32_t flow)
@@ -466,7 +470,7 @@ static void udp_send_tap_icmp6(const struct ctx *c,
 	tap_push_uh6(&msg.uh, eaddr, eport, oaddr, oport, in, dlen);
 	memcpy(&msg.data, in, dlen);
 
-	tap_icmp6_send(c, saddr, eaddr, &msg, msglen);
+	tap_icmp6_send(c, saddr, eaddr, &msg, uflow->f.tap_omac, msglen);
 }
 
 /**
@@ -626,12 +630,12 @@ static int udp_sock_recverr(const struct ctx *c, int s, flow_sidx_t sidx,
 	if (hdr->cmsg_level == IPPROTO_IP &&
 	    (o4 = inany_v4(&otap)) && inany_v4(&toside->eaddr)) {
 		dlen = MIN(dlen, ICMP4_MAX_DLEN);
-		udp_send_tap_icmp4(c, ee, toside, *o4, data, dlen);
+		udp_send_tap_icmp4(c, ee, uflow, toside, *o4, data, dlen);
 		return 1;
 	}
 
 	if (hdr->cmsg_level == IPPROTO_IPV6 && !inany_v4(&toside->eaddr)) {
-		udp_send_tap_icmp6(c, ee, toside, &otap.a6, data, dlen,
+		udp_send_tap_icmp6(c, ee, uflow, toside, &otap.a6, data, dlen,
 				   FLOW_IDX(uflow));
 		return 1;
 	}
-- 
@@ -385,6 +385,7 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
  * udp_send_tap_icmp4() - Construct and send ICMPv4 to local peer
  * @c:		Execution context
  * @ee:	Extended error descriptor
+ * @uflow:	UDP flow
  * @toside:	Destination side of flow
  * @saddr:	Address of ICMP generating node
  * @in:	First bytes (max 8) of original UDP message body
@@ -392,6 +393,7 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
  */
 static void udp_send_tap_icmp4(const struct ctx *c,
 			       const struct sock_extended_err *ee,
+			       const struct udp_flow *uflow,
 			       const struct flowside *toside,
 			       struct in_addr saddr,
 			       const void *in, size_t dlen)
@@ -421,7 +423,7 @@ static void udp_send_tap_icmp4(const struct ctx *c,
 	tap_push_uh4(&msg.uh, eaddr, eport, oaddr, oport, in, dlen);
 	memcpy(&msg.data, in, dlen);
 
-	tap_icmp4_send(c, saddr, eaddr, &msg, msglen);
+	tap_icmp4_send(c, saddr, eaddr, &msg, uflow->f.tap_omac, msglen);
 }
 
 
@@ -429,6 +431,7 @@ static void udp_send_tap_icmp4(const struct ctx *c,
  * udp_send_tap_icmp6() - Construct and send ICMPv6 to local peer
  * @c:		Execution context
  * @ee:	Extended error descriptor
+ * @uflow:	UDP flow
  * @toside:	Destination side of flow
  * @saddr:	Address of ICMP generating node
  * @in:	First bytes (max 1232) of original UDP message body
@@ -437,6 +440,7 @@ static void udp_send_tap_icmp4(const struct ctx *c,
  */
 static void udp_send_tap_icmp6(const struct ctx *c,
 			       const struct sock_extended_err *ee,
+			       const struct udp_flow *uflow,
 			       const struct flowside *toside,
 			       const struct in6_addr *saddr,
 			       void *in, size_t dlen, uint32_t flow)
@@ -466,7 +470,7 @@ static void udp_send_tap_icmp6(const struct ctx *c,
 	tap_push_uh6(&msg.uh, eaddr, eport, oaddr, oport, in, dlen);
 	memcpy(&msg.data, in, dlen);
 
-	tap_icmp6_send(c, saddr, eaddr, &msg, msglen);
+	tap_icmp6_send(c, saddr, eaddr, &msg, uflow->f.tap_omac, msglen);
 }
 
 /**
@@ -626,12 +630,12 @@ static int udp_sock_recverr(const struct ctx *c, int s, flow_sidx_t sidx,
 	if (hdr->cmsg_level == IPPROTO_IP &&
 	    (o4 = inany_v4(&otap)) && inany_v4(&toside->eaddr)) {
 		dlen = MIN(dlen, ICMP4_MAX_DLEN);
-		udp_send_tap_icmp4(c, ee, toside, *o4, data, dlen);
+		udp_send_tap_icmp4(c, ee, uflow, toside, *o4, data, dlen);
 		return 1;
 	}
 
 	if (hdr->cmsg_level == IPPROTO_IPV6 && !inany_v4(&toside->eaddr)) {
-		udp_send_tap_icmp6(c, ee, toside, &otap.a6, data, dlen,
+		udp_send_tap_icmp6(c, ee, uflow, toside, &otap.a6, data, dlen,
 				   FLOW_IDX(uflow));
 		return 1;
 	}
-- 
2.50.1


  parent reply	other threads:[~2025-08-20  3:10 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-20  3:09 [PATCH v4 0/9] Use true MAC address of LAN local remote hosts Jon Maloy
2025-08-20  3:09 ` [PATCH v4 1/9] netlink: add function to extract MAC addresses from NDP/ARP table Jon Maloy
2025-08-21  0:57   ` David Gibson
2025-08-20  3:09 ` [PATCH v4 2/9] arp/ndp: respond with true MAC address of LAN local remote hosts Jon Maloy
2025-08-21  1:18   ` David Gibson
2025-08-20  3:09 ` [PATCH v4 3/9] flow: add MAC address of LAN local remote hosts to flow Jon Maloy
2025-08-21  1:28   ` David Gibson
2025-08-20  3:10 ` [PATCH v4 4/9] udp: forward external source MAC address through tap interface Jon Maloy
2025-08-21  1:32   ` David Gibson
2025-08-20  3:10 ` [PATCH v4 5/9] tcp: " Jon Maloy
2025-08-21  1:37   ` David Gibson
2025-08-20  3:10 ` [PATCH v4 6/9] tap: change signature of function tap_push_l2h() Jon Maloy
2025-08-21  1:39   ` David Gibson
2025-08-20  3:10 ` [PATCH v4 7/9] tcp: make tcp_rst_no_conn() respond with correct MAC address Jon Maloy
2025-08-21  1:46   ` David Gibson
2025-08-20  3:10 ` Jon Maloy [this message]
2025-08-21  1:51   ` [PATCH v4 8/9] icmp: let icmp use mac address from flowside structure David Gibson
2025-08-20  3:10 ` [PATCH v4 9/9] fwd: Added cache table for ARP/NDP contents Jon Maloy
2025-08-21  2:03   ` David Gibson
2025-08-21 10:53     ` Stefano Brivio
2025-08-25  1:48       ` David Gibson

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