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-rw-r--r--net/colo.c2
-rw-r--r--net/colo.h9
-rw-r--r--net/filter-rewriter.c109
3 files changed, 104 insertions, 16 deletions
diff --git a/net/colo.c b/net/colo.c
index 6dda4ed66e..97c8fc928f 100644
--- a/net/colo.c
+++ b/net/colo.c
@@ -137,7 +137,7 @@ Connection *connection_new(ConnectionKey *key)
conn->ip_proto = key->ip_proto;
conn->processing = false;
conn->offset = 0;
- conn->syn_flag = 0;
+ conn->tcp_state = TCPS_CLOSED;
conn->pack = 0;
conn->sack = 0;
g_queue_init(&conn->primary_list);
diff --git a/net/colo.h b/net/colo.h
index da6c36dcf7..0277e0e9ba 100644
--- a/net/colo.h
+++ b/net/colo.h
@@ -18,6 +18,7 @@
#include "slirp/slirp.h"
#include "qemu/jhash.h"
#include "qemu/timer.h"
+#include "slirp/tcp.h"
#define HASHTABLE_MAX_SIZE 16384
@@ -81,11 +82,9 @@ typedef struct Connection {
uint32_t sack;
/* offset = secondary_seq - primary_seq */
tcp_seq offset;
- /*
- * we use this flag update offset func
- * run once in independent tcp connection
- */
- int syn_flag;
+
+ int tcp_state; /* TCP FSM state */
+ tcp_seq fin_ack_seq; /* the seq of 'fin=1,ack=1' */
} Connection;
uint32_t connection_key_hash(const void *opaque);
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
index f584e4eba4..dd323faf61 100644
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -59,9 +59,9 @@ static int is_tcp_packet(Packet *pkt)
}
/* handle tcp packet from primary guest */
-static int handle_primary_tcp_pkt(NetFilterState *nf,
+static int handle_primary_tcp_pkt(RewriterState *rf,
Connection *conn,
- Packet *pkt)
+ Packet *pkt, ConnectionKey *key)
{
struct tcphdr *tcp_pkt;
@@ -74,23 +74,28 @@ static int handle_primary_tcp_pkt(NetFilterState *nf,
trace_colo_filter_rewriter_conn_offset(conn->offset);
}
+ if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN)) &&
+ conn->tcp_state == TCPS_SYN_SENT) {
+ conn->tcp_state = TCPS_ESTABLISHED;
+ }
+
if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) {
/*
* we use this flag update offset func
* run once in independent tcp connection
*/
- conn->syn_flag = 1;
+ conn->tcp_state = TCPS_SYN_RECEIVED;
}
if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK)) {
- if (conn->syn_flag) {
+ if (conn->tcp_state == TCPS_SYN_RECEIVED) {
/*
* offset = secondary_seq - primary seq
* ack packet sent by guest from primary node,
* so we use th_ack - 1 get primary_seq
*/
conn->offset -= (ntohl(tcp_pkt->th_ack) - 1);
- conn->syn_flag = 0;
+ conn->tcp_state = TCPS_ESTABLISHED;
}
if (conn->offset) {
/* handle packets to the secondary from the primary */
@@ -99,15 +104,66 @@ static int handle_primary_tcp_pkt(NetFilterState *nf,
net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
pkt->size - pkt->vnet_hdr_len);
}
+
+ /*
+ * Passive close step 3
+ */
+ if ((conn->tcp_state == TCPS_LAST_ACK) &&
+ (ntohl(tcp_pkt->th_ack) == (conn->fin_ack_seq + 1))) {
+ conn->tcp_state = TCPS_CLOSED;
+ g_hash_table_remove(rf->connection_track_table, key);
+ }
+ }
+
+ if ((tcp_pkt->th_flags & TH_FIN) == TH_FIN) {
+ /*
+ * Passive close.
+ * Step 1:
+ * The *server* side of this connect is VM, *client* tries to close
+ * the connection. We will into CLOSE_WAIT status.
+ *
+ * Step 2:
+ * In this step we will into LAST_ACK status.
+ *
+ * We got 'fin=1, ack=1' packet from server side, we need to
+ * record the seq of 'fin=1, ack=1' packet.
+ *
+ * Step 3:
+ * We got 'ack=1' packets from client side, it acks 'fin=1, ack=1'
+ * packet from server side. From this point, we can ensure that there
+ * will be no packets in the connection, except that, some errors
+ * happen between the path of 'filter object' and vNIC, if this rare
+ * case really happen, we can still create a new connection,
+ * So it is safe to remove the connection from connection_track_table.
+ *
+ */
+ if (conn->tcp_state == TCPS_ESTABLISHED) {
+ conn->tcp_state = TCPS_CLOSE_WAIT;
+ }
+
+ /*
+ * Active close step 2.
+ */
+ if (conn->tcp_state == TCPS_FIN_WAIT_1) {
+ conn->tcp_state = TCPS_TIME_WAIT;
+ /*
+ * For simplify implementation, we needn't wait 2MSL time
+ * in filter rewriter. Because guest kernel will track the
+ * TCP status and wait 2MSL time, if client resend the FIN
+ * packet, guest will apply the last ACK too.
+ */
+ conn->tcp_state = TCPS_CLOSED;
+ g_hash_table_remove(rf->connection_track_table, key);
+ }
}
return 0;
}
/* handle tcp packet from secondary guest */
-static int handle_secondary_tcp_pkt(NetFilterState *nf,
+static int handle_secondary_tcp_pkt(RewriterState *rf,
Connection *conn,
- Packet *pkt)
+ Packet *pkt, ConnectionKey *key)
{
struct tcphdr *tcp_pkt;
@@ -121,7 +177,8 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf,
trace_colo_filter_rewriter_conn_offset(conn->offset);
}
- if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) {
+ if (conn->tcp_state == TCPS_SYN_RECEIVED &&
+ ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) {
/*
* save offset = secondary_seq and then
* in handle_primary_tcp_pkt make offset
@@ -130,6 +187,12 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf,
conn->offset = ntohl(tcp_pkt->th_seq);
}
+ /* VM active connect */
+ if (conn->tcp_state == TCPS_CLOSED &&
+ ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) {
+ conn->tcp_state = TCPS_SYN_SENT;
+ }
+
if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK) {
/* Only need to adjust seq while offset is Non-zero */
if (conn->offset) {
@@ -141,6 +204,32 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf,
}
}
+ /*
+ * Passive close step 2:
+ */
+ if (conn->tcp_state == TCPS_CLOSE_WAIT &&
+ (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == (TH_ACK | TH_FIN)) {
+ conn->fin_ack_seq = ntohl(tcp_pkt->th_seq);
+ conn->tcp_state = TCPS_LAST_ACK;
+ }
+
+ /*
+ * Active close
+ *
+ * Step 1:
+ * The *server* side of this connect is VM, *server* tries to close
+ * the connection.
+ *
+ * Step 2:
+ * We will into CLOSE_WAIT status.
+ * We simplify the TCPS_FIN_WAIT_2, TCPS_TIME_WAIT and
+ * CLOSING status.
+ */
+ if (conn->tcp_state == TCPS_ESTABLISHED &&
+ (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == TH_FIN) {
+ conn->tcp_state = TCPS_FIN_WAIT_1;
+ }
+
return 0;
}
@@ -190,7 +279,7 @@ static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
if (sender == nf->netdev) {
/* NET_FILTER_DIRECTION_TX */
- if (!handle_primary_tcp_pkt(nf, conn, pkt)) {
+ if (!handle_primary_tcp_pkt(s, conn, pkt, &key)) {
qemu_net_queue_send(s->incoming_queue, sender, 0,
(const uint8_t *)pkt->data, pkt->size, NULL);
packet_destroy(pkt, NULL);
@@ -203,7 +292,7 @@ static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
}
} else {
/* NET_FILTER_DIRECTION_RX */
- if (!handle_secondary_tcp_pkt(nf, conn, pkt)) {
+ if (!handle_secondary_tcp_pkt(s, conn, pkt, &key)) {
qemu_net_queue_send(s->incoming_queue, sender, 0,
(const uint8_t *)pkt->data, pkt->size, NULL);
packet_destroy(pkt, NULL);
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-26 04:34:29 +0000