After a net connection is closed, we didn't clear its releated resources
in connection_track_table, which will lead to memory leak.
Let't track the state of net connection, if it is closed, its related
resources will be cleared up.
Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
---
net/colo.h | 4 +++
net/filter-rewriter.c | 70 +++++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 67 insertions(+), 7 deletions(-)
diff --git a/net/colo.h b/net/colo.h
index 7c524f3..cd9027f 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
@@ -69,6 +70,9 @@ typedef struct Connection {
* 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 c4ab91c..7e7ec35 100644
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -60,9 +60,9 @@ 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;
@@ -97,15 +97,45 @@ static int handle_primary_tcp_pkt(NetFilterState *nf,
tcp_pkt->th_ack = htonl(ntohl(tcp_pkt->th_ack) + conn->offset);
net_checksum_calculate((uint8_t *)pkt->data, pkt->size);
+ /*
+ * Case 1:
+ * The *server* side of this connect is VM, *client* tries to close
+ * the connection.
+ *
+ * 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_LAST_ACK) &&
+ (ntohl(tcp_pkt->th_ack) == (conn->fin_ack_seq + 1))) {
+ fprintf(stderr, "Remove conn "
+ g_hash_table_remove(rf->connection_track_table, key);
+ }
+ }
+ /*
+ * Case 2:
+ * The *server* side of this connect is VM, *server* tries to close
+ * the connection.
+ *
+ * We got 'fin=1, ack=1' packet from client side, we need to
+ * record the seq of 'fin=1, ack=1' packet.
+ */
+ if ((tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == (TH_ACK | TH_FIN)) {
+ conn->fin_ack_seq = htonl(tcp_pkt->th_seq);
+ conn->tcp_state = TCPS_LAST_ACK;
}
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;
@@ -133,8 +163,34 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf,
tcp_pkt->th_seq = htonl(ntohl(tcp_pkt->th_seq) - conn->offset);
net_checksum_calculate((uint8_t *)pkt->data, pkt->size);
+ /*
+ * Case 2:
+ * The *server* side of this connect is VM, *server* tries to close
+ * the connection.
+ *
+ * We got 'ack=1' packets from server side, it acks 'fin=1, ack=1'
+ * packet from client side. Like Case 1, there should be no packets
+ * in the connection from now know, But the difference here is
+ * if the packet is lost, We will get the resent 'fin=1,ack=1' packet.
+ * TODO: Fix above case.
+ */
+ if ((conn->tcp_state == TCPS_LAST_ACK) &&
+ (ntohl(tcp_pkt->th_ack) == (conn->fin_ack_seq + 1))) {
+ g_hash_table_remove(rf->connection_track_table, key);
+ }
+ }
+ /*
+ * Case 1:
+ * The *server* side of this connect is VM, *client* tries to close
+ * the connection.
+ *
+ * We got 'fin=1, ack=1' packet from server side, we need to
+ * record the seq of 'fin=1, ack=1' packet.
+ */
+ if ((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;
}
-
return 0;
}
@@ -178,7 +234,7 @@ 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);
@@ -191,7 +247,7 @@ 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);
--
1.8.3.1
