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
Reviewed-by: David Gibson
---
v3: - Adapted to the move of external MAC address from struct flowside
to struct flow_common
v4: - Adapted to name changes in previous commits in this series
v5: - Added conditional lookup in ARP/NDP if the flow's tap_omac is
undefined
v6: - Looking up MAC of ICMP generating node in udp_send_tap_icmp4/6()
when available, instead trusting the contents of flow->tap_omac.
v12: - Using MAC_IS_UNDEF() instead of MAC_IS_ZERO()
- Comment update after feedback from Stefano
v13: - No changes
v15: - Minor change in comment after feedback from Stefano
---
icmp.c | 8 ++++++--
ndp.c | 2 +-
tap.c | 10 ++++++----
tap.h | 4 ++--
udp.c | 12 ++++++++++--
5 files changed, 25 insertions(+), 11 deletions(-)
diff --git a/icmp.c b/icmp.c
index 6dffafb..158b98f 100644
--- a/icmp.c
+++ b/icmp.c
@@ -125,17 +125,21 @@ void icmp_sock_handler(const struct ctx *c, union epoll_ref ref)
flow_dbg(pingf, "echo reply to tap, ID: %"PRIu16", seq: %"PRIu16,
ini->eport, seq);
+ /* Check if neighbour table has a recorded MAC address */
+ if (MAC_IS_UNDEF(pingf->f.tap_omac))
+ fwd_neigh_mac_get(c, &ini->oaddr, pingf->f.tap_omac);
+
if (pingf->f.type == FLOW_PING4) {
const struct in_addr *saddr = inany_v4(&ini->oaddr);
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 430d420..a33239d 100644
--- a/ndp.c
+++ b/ndp.c
@@ -184,7 +184,7 @@ 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 8906b24..7d79f95 100644
--- a/tap.c
+++ b/tap.c
@@ -277,13 +277,14 @@ 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, c->our_tap_mac, 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);
@@ -384,14 +385,15 @@ 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, c->our_tap_mac, 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 02f7761..1864173 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 3acc401..3981e9b 100644
--- a/udp.c
+++ b/udp.c
@@ -400,6 +400,8 @@ static void udp_send_tap_icmp4(const struct ctx *c,
struct in_addr eaddr = toside->eaddr.v4mapped.a4;
in_port_t eport = toside->eport;
in_port_t oport = toside->oport;
+ union inany_addr saddr_any;
+ uint8_t tap_omac[ETH_ALEN];
struct {
struct icmphdr icmp4h;
struct iphdr ip4h;
@@ -421,7 +423,10 @@ 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);
+ /* Try to obtain the MAC address of the generating node */
+ saddr_any = inany_from_v4(saddr);
+ fwd_neigh_mac_get(c, &saddr_any, tap_omac);
+ tap_icmp4_send(c, saddr, eaddr, &msg, tap_omac, msglen);
}
@@ -445,6 +450,7 @@ static void udp_send_tap_icmp6(const struct ctx *c,
const struct in6_addr *eaddr = &toside->eaddr.a6;
in_port_t eport = toside->eport;
in_port_t oport = toside->oport;
+ uint8_t tap_omac[ETH_ALEN];
struct {
struct icmp6_hdr icmp6h;
struct ipv6hdr ip6h;
@@ -466,7 +472,9 @@ 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);
+ /* Try to obtain the MAC address of the generating node */
+ fwd_neigh_mac_get(c, (union inany_addr *) saddr, tap_omac);
+ tap_icmp6_send(c, saddr, eaddr, &msg, tap_omac, msglen);
}
/**
--
2.50.1