From 5d35ac333d8f9cfdfa559468a3351077e87125b8 Mon Sep 17 00:00:00 2001 From: Jon Maloy Date: Thu, 23 Oct 2025 21:29:29 -0400 Subject: flow: add MAC address of LAN local remote hosts to flow MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When communicating with remote hosts on the local network, some guest applications want to see the real MAC address of that host instead of PASST/PASTA's own tap address. The flow_common structure is a convenient location for storing that address, so we do that in this commit. Note that we don´t add actual usage of this address here, that will be done in later commits. Signed-off-by: Jon Maloy Reviewed-by: David Gibson Signed-off-by: Stefano Brivio --- flow.c | 2 ++ flow.h | 2 ++ util.h | 2 ++ 3 files changed, 6 insertions(+) diff --git a/flow.c b/flow.c index feefda3..a57d7b9 100644 --- a/flow.c +++ b/flow.c @@ -449,6 +449,7 @@ struct flowside *flow_target(const struct ctx *c, union flow *flow, switch (f->pif[INISIDE]) { case PIF_TAP: + memcpy(f->tap_omac, MAC_UNDEF, ETH_ALEN); tgtpif = fwd_nat_from_tap(c, proto, ini, tgt); break; @@ -458,6 +459,7 @@ struct flowside *flow_target(const struct ctx *c, union flow *flow, case PIF_HOST: tgtpif = fwd_nat_from_host(c, proto, ini, tgt); + fwd_neigh_mac_get(c, &tgt->oaddr, f->tap_omac); break; default: diff --git a/flow.h b/flow.h index cac618a..f342895 100644 --- a/flow.h +++ b/flow.h @@ -177,6 +177,7 @@ int flowside_connect(const struct ctx *c, int s, * @type: Type of packet flow * @pif[]: Interface for each side of the flow * @side[]: Information for each side of the flow + * @tap_omac: MAC address of remote endpoint as seen from the guest */ struct flow_common { #ifdef __GNUC__ @@ -192,6 +193,7 @@ struct flow_common { #endif uint8_t pif[SIDES]; struct flowside side[SIDES]; + uint8_t tap_omac[6]; }; #define FLOW_INDEX_BITS 17 /* 128k - 1 */ diff --git a/util.h b/util.h index 22eaac5..6fc8f5d 100644 --- a/util.h +++ b/util.h @@ -101,6 +101,8 @@ void abort_with_msg(const char *fmt, ...) ((uint8_t [ETH_ALEN]){ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }) #define MAC_ZERO ((uint8_t [ETH_ALEN]){ 0 }) #define MAC_IS_ZERO(addr) (!memcmp((addr), MAC_ZERO, ETH_ALEN)) +#define MAC_UNDEF MAC_BROADCAST +#define MAC_IS_UNDEF(addr) (!memcmp((addr), MAC_UNDEF, ETH_ALEN)) #ifndef __bswap_constant_16 #define __bswap_constant_16(x) \ -- cgit v1.2.3