tcp_rst_no_conn() needs to identify and specify which source MAC
address to use when sending an RST to the guest. This is because
it doesn't have access to any flow structure where this address
could be fetched.
Signed-off-by: Jon Maloy
---
v3: - Adapted to the signature change in nl_mac_get() function, so that
we now consider only the template interface when checking the
ARP/NDP table.
---
tcp.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/tcp.c b/tcp.c
index 3ecf9e8..8c502ea 100644
--- a/tcp.c
+++ b/tcp.c
@@ -309,6 +309,7 @@
#include "tcp_internal.h"
#include "tcp_buf.h"
#include "tcp_vu.h"
+#include "netlink.h"
#ifndef __USE_MISC
/* From Linux UAPI, missing in netinet/tcp.h provided by musl */
@@ -1888,17 +1889,29 @@ static void tcp_rst_no_conn(const struct ctx *c, int af,
const struct tcphdr *th, size_t l4len)
{
struct iov_tail payload = IOV_TAIL(NULL, 0, 0);
+ unsigned char src_mac[ETH_ALEN];
+ union inany_addr tgt;
struct tcphdr *rsth;
char buf[USHRT_MAX];
uint32_t psum = 0;
size_t rst_l2len;
+ int ifi;
/* Don't respond to RSTs without a connection */
if (th->rst)
return;
+ /* Respond with true MAC address if remote host is on
+ * the template interface's network segment
+ */
+ ifi = af == AF_INET ? c->ifi4 : c->ifi6;
+ memcpy(src_mac, c->our_tap_mac, ETH_ALEN);
+ inany_from_af(&tgt, af, daddr);
+ if (!inany_nat(c, &tgt))
+ nl_mac_get(nl_sock, &tgt, ifi, src_mac);
+
if (af == AF_INET) {
- 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);
const struct in_addr *rst_src = daddr;
const struct in_addr *rst_dst = saddr;
@@ -1908,7 +1921,7 @@ 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, NULL, ETH_P_IPV6);
+ struct ipv6hdr *ip6h = tap_push_l2h(c, buf, src_mac, ETH_P_IPV6);
const struct in6_addr *rst_src = daddr;
const struct in6_addr *rst_dst = saddr;
--
2.48.1