We forward the incoming mac address through the tap interface when
receiving incoming packets from network local hosts.
This is a part of the solution to bug
https://bugs.passt.top/show_bug.cgi?id=120
Signed-off-by: Jon Maloy
Reviewed-by: David Gibson
---
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.
v4: - Adapted to previous name changes in this series
v5: - Added lookup in ARP/NDP cache and/or table on incoming messages
in case flow->tap_omac wasn't initialized at flow creation,
i.e., the flow was initiated from the guest.
v6: - Using MAC_IS_ZERO() instead of mac_undefined()
- I ignored David's suggestion to move the test for
undefined flow->tap_omac to tcp_{buf,vu}_data_from_sock(), at
least for now. It looks like a sub-optimization to first have to
look up the flow instance in these calls, and then do the
test for MAC_IS_ZERO(), even though we might in theory end up
with fewer such calls (how often?).
---
passt.c | 7 +++----
passt.h | 3 +--
pasta.c | 2 +-
tap.c | 2 +-
tcp.c | 13 +++++++++++--
tcp.h | 2 +-
tcp_buf.c | 37 +++++++++++++++++--------------------
tcp_internal.h | 4 ++--
tcp_vu.c | 5 ++---
9 files changed, 39 insertions(+), 36 deletions(-)
diff --git a/passt.c b/passt.c
index fdd275a..a2ce2d9 100644
--- a/passt.c
+++ b/passt.c
@@ -159,11 +159,10 @@ static void timer_init(struct ctx *c, const struct timespec *now)
/**
* proto_update_l2_buf() - Update scatter-gather L2 buffers in protocol handlers
* @eth_d: Ethernet destination address, NULL if unchanged
- * @eth_s: Ethernet source address, NULL if unchanged
*/
-void proto_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
+void proto_update_l2_buf(const unsigned char *eth_d)
{
- tcp_update_l2_buf(eth_d, eth_s);
+ tcp_update_l2_buf(eth_d);
udp_update_l2_buf(eth_d);
}
@@ -314,7 +313,7 @@ int main(int argc, char **argv)
if ((!c.no_udp && udp_init(&c)) || (!c.no_tcp && tcp_init(&c)))
_exit(EXIT_FAILURE);
- proto_update_l2_buf(c.guest_mac, c.our_tap_mac);
+ proto_update_l2_buf(c.guest_mac);
if (c.ifi4 && !c.no_dhcp)
dhcp_init();
diff --git a/passt.h b/passt.h
index 0075eb4..ff0236c 100644
--- a/passt.h
+++ b/passt.h
@@ -326,7 +326,6 @@ struct ctx {
bool migrate_exit;
};
-void proto_update_l2_buf(const unsigned char *eth_d,
- const unsigned char *eth_s);
+void proto_update_l2_buf(const unsigned char *eth_d);
#endif /* PASST_H */
diff --git a/pasta.c b/pasta.c
index 687406b..a42cfd8 100644
--- a/pasta.c
+++ b/pasta.c
@@ -411,7 +411,7 @@ void pasta_ns_conf(struct ctx *c)
}
}
- proto_update_l2_buf(c->guest_mac, NULL);
+ proto_update_l2_buf(c->guest_mac);
}
/**
diff --git a/tap.c b/tap.c
index 399eeaa..250a0f6 100644
--- a/tap.c
+++ b/tap.c
@@ -1101,7 +1101,7 @@ void tap_add_packet(struct ctx *c, struct iov_tail *data,
memcpy(c->guest_mac, eh->h_source, ETH_ALEN);
debug("New guest MAC address observed: %s",
eth_ntop(c->guest_mac, bufmac, sizeof(bufmac)));
- proto_update_l2_buf(c->guest_mac, NULL);
+ proto_update_l2_buf(c->guest_mac);
}
switch (ntohs(eh->h_proto)) {
diff --git a/tcp.c b/tcp.c
index 48b1ef2..af05d35 100644
--- a/tcp.c
+++ b/tcp.c
@@ -919,6 +919,7 @@ static void tcp_fill_header(struct tcphdr *th,
/**
* tcp_fill_headers() - Fill 802.3, IP, TCP headers
+ * @c: Execution context
* @conn: Connection pointer
* @taph: tap backend specific header
* @ip4h: Pointer to IPv4 header, or NULL
@@ -929,14 +930,15 @@ static void tcp_fill_header(struct tcphdr *th,
* @seq: Sequence number for this segment
* @no_tcp_csum: Do not set TCP checksum
*/
-void tcp_fill_headers(const struct tcp_tap_conn *conn,
- struct tap_hdr *taph,
+void tcp_fill_headers(const struct ctx *c, struct tcp_tap_conn *conn,
+ struct tap_hdr *taph, struct ethhdr *eh,
struct iphdr *ip4h, struct ipv6hdr *ip6h,
struct tcphdr *th, struct iov_tail *payload,
const uint16_t *ip4_check, uint32_t seq, bool no_tcp_csum)
{
const struct flowside *tapside = TAPFLOW(conn);
size_t l4len = iov_tail_size(payload) + sizeof(*th);
+ uint8_t *omac = conn->f.tap_omac;
size_t l3len = l4len;
uint32_t psum = 0;
@@ -962,6 +964,7 @@ void tcp_fill_headers(const struct tcp_tap_conn *conn,
psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
*src4, *dst4);
}
+ eh->h_proto = htons_constant(ETH_P_IP);
}
if (ip6h) {
@@ -982,8 +985,14 @@ void tcp_fill_headers(const struct tcp_tap_conn *conn,
&ip6h->saddr,
&ip6h->daddr);
}
+ eh->h_proto = htons_constant(ETH_P_IPV6);
}
+ /* Make one attempt to find true MAC address in ARP/NDP table */
+ if (MAC_IS_ZERO(omac))
+ fwd_neigh_mac_get(c, &tapside->oaddr, omac);
+ eth_update_mac(eh, NULL, omac);
+
tcp_fill_header(th, conn, seq);
if (no_tcp_csum)
diff --git a/tcp.h b/tcp.h
index 234a803..c1b8385 100644
--- a/tcp.h
+++ b/tcp.h
@@ -24,7 +24,7 @@ int tcp_init(struct ctx *c);
void tcp_timer(struct ctx *c, const struct timespec *now);
void tcp_defer_handler(struct ctx *c);
-void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);
+void tcp_update_l2_buf(const unsigned char *eth_d);
extern bool peek_offset_cap;
diff --git a/tcp_buf.c b/tcp_buf.c
index a493b5a..f256dcc 100644
--- a/tcp_buf.c
+++ b/tcp_buf.c
@@ -40,8 +40,7 @@
/* Static buffers */
/* Ethernet header for IPv4 and IPv6 frames */
-static struct ethhdr tcp4_eth_src;
-static struct ethhdr tcp6_eth_src;
+static struct ethhdr tcp_eth_hdr[TCP_FRAMES_MEM];
static struct tap_hdr tcp_payload_tap_hdr[TCP_FRAMES_MEM];
@@ -67,12 +66,13 @@ static struct iovec tcp_l2_iov[TCP_FRAMES_MEM][TCP_NUM_IOVS];
/**
* tcp_update_l2_buf() - Update Ethernet header buffers with addresses
* @eth_d: Ethernet destination address, NULL if unchanged
- * @eth_s: Ethernet source address, NULL if unchanged
*/
-void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
+void tcp_update_l2_buf(const unsigned char *eth_d)
{
- eth_update_mac(&tcp4_eth_src, eth_d, eth_s);
- eth_update_mac(&tcp6_eth_src, eth_d, eth_s);
+ int i;
+
+ for (i = 0; i < TCP_FRAMES_MEM; i++)
+ eth_update_mac(&tcp_eth_hdr[i], eth_d, NULL);
}
/**
@@ -85,9 +85,6 @@ void tcp_sock_iov_init(const struct ctx *c)
struct iphdr iph = L2_BUF_IP4_INIT(IPPROTO_TCP);
int i;
- tcp6_eth_src.h_proto = htons_constant(ETH_P_IPV6);
- tcp4_eth_src.h_proto = htons_constant(ETH_P_IP);
-
for (i = 0; i < ARRAY_SIZE(tcp_payload); i++) {
tcp6_payload_ip[i] = ip6;
tcp4_payload_ip[i] = iph;
@@ -149,13 +146,15 @@ void tcp_payload_flush(const struct ctx *c)
/**
* tcp_l2_buf_fill_headers() - Fill 802.3, IP, TCP headers in pre-cooked buffers
+ * @c: Execution context
* @conn: Connection pointer
* @iov: Pointer to an array of iovec of TCP pre-cooked buffers
* @check: Checksum, if already known
* @seq: Sequence number for this segment
* @no_tcp_csum: Do not set TCP checksum
*/
-static void tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
+static void tcp_l2_buf_fill_headers(const struct ctx *c,
+ struct tcp_tap_conn *conn,
struct iovec *iov, const uint16_t *check,
uint32_t seq, bool no_tcp_csum)
{
@@ -164,6 +163,7 @@ static void tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
struct tap_hdr *taph = iov[TCP_IOV_TAP].iov_base;
const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *a4 = inany_v4(&tapside->oaddr);
+ struct ethhdr *eh = iov[TCP_IOV_ETH].iov_base;
struct ipv6hdr *ip6h = NULL;
struct iphdr *ip4h = NULL;
@@ -172,7 +172,7 @@ static void tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
else
ip6h = iov[TCP_IOV_IP].iov_base;
- tcp_fill_headers(conn, taph, ip4h, ip6h, th, &tail,
+ tcp_fill_headers(c, conn, taph, eh, ip4h, ip6h, th, &tail,
check, seq, no_tcp_csum);
}
@@ -194,14 +194,12 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
int ret;
iov = tcp_l2_iov[tcp_payload_used];
- if (CONN_V4(conn)) {
+ if (CONN_V4(conn))
iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[tcp_payload_used]);
- iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
- } else {
+ else
iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[tcp_payload_used]);
- iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
- }
+ iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp_eth_hdr[tcp_payload_used]);
payload = iov[TCP_IOV_PAYLOAD].iov_base;
seq = conn->seq_to_tap;
ret = tcp_prepare_flags(c, conn, flags, &payload->th,
@@ -212,7 +210,7 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
tcp_frame_conns[tcp_payload_used++] = conn;
l4len = optlen + sizeof(struct tcphdr);
iov[TCP_IOV_PAYLOAD].iov_len = l4len;
- tcp_l2_buf_fill_headers(conn, iov, NULL, seq, false);
+ tcp_l2_buf_fill_headers(c, conn, iov, NULL, seq, false);
if (flags & DUP_ACK) {
struct iovec *dup_iov = tcp_l2_iov[tcp_payload_used];
@@ -260,11 +258,10 @@ static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn,
check = &iph->check;
}
iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[tcp_payload_used]);
- iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
} else if (CONN_V6(conn)) {
iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[tcp_payload_used]);
- iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
}
+ iov[TCP_IOV_ETH].iov_base = &tcp_eth_hdr[tcp_payload_used];
payload = iov[TCP_IOV_PAYLOAD].iov_base;
payload->th.th_off = sizeof(struct tcphdr) / 4;
payload->th.th_x2 = 0;
@@ -272,7 +269,7 @@ static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn,
payload->th.ack = 1;
payload->th.psh = push;
iov[TCP_IOV_PAYLOAD].iov_len = dlen + sizeof(struct tcphdr);
- tcp_l2_buf_fill_headers(conn, iov, check, seq, false);
+ tcp_l2_buf_fill_headers(c, conn, iov, check, seq, false);
if (++tcp_payload_used > TCP_FRAMES_MEM - 1)
tcp_payload_flush(c);
}
diff --git a/tcp_internal.h b/tcp_internal.h
index 5cb6cba..f55025c 100644
--- a/tcp_internal.h
+++ b/tcp_internal.h
@@ -174,8 +174,8 @@ void tcp_rst_do(const struct ctx *c, struct tcp_tap_conn *conn);
struct tcp_info_linux;
-void tcp_fill_headers(const struct tcp_tap_conn *conn,
- struct tap_hdr *taph,
+void tcp_fill_headers(const struct ctx *c, struct tcp_tap_conn *conn,
+ struct tap_hdr *taph, struct ethhdr *eh,
struct iphdr *ip4h, struct ipv6hdr *ip6h,
struct tcphdr *th, struct iov_tail *payload,
const uint16_t *ip4_check, uint32_t seq, bool no_tcp_csum);
diff --git a/tcp_vu.c b/tcp_vu.c
index ebd3a1e..0c17884 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -135,7 +135,7 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
flags_elem[0].in_sg[0].iov_len = hdrlen + optlen;
payload = IOV_TAIL(flags_elem[0].in_sg, 1, hdrlen);
- tcp_fill_headers(conn, NULL, ip4h, ip6h, th, &payload,
+ tcp_fill_headers(c, conn, NULL, eh, ip4h, ip6h, th, &payload,
NULL, seq, !*c->pcap);
if (*c->pcap) {
@@ -308,7 +308,6 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn *conn,
eh = vu_eth(base);
memcpy(eh->h_dest, c->guest_mac, sizeof(eh->h_dest));
- memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source));
/* initialize header */
@@ -332,7 +331,7 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn *conn,
th->ack = 1;
th->psh = push;
- tcp_fill_headers(conn, NULL, ip4h, ip6h, th, &payload,
+ tcp_fill_headers(c, conn, NULL, eh, ip4h, ip6h, th, &payload,
*check, conn->seq_to_tap, no_tcp_csum);
if (ip4h)
*check = &ip4h->check;
--
2.50.1