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David Alan Gilbert" , Jason Wang , Eric Blake , Markus Armbruster Date: Mon, 23 Jul 2018 03:33:31 +0800 Message-Id: <20180722193350.6028-2-zhangckid@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180722193350.6028-1-zhangckid@gmail.com> References: <20180722193350.6028-1-zhangckid@gmail.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::542 Subject: [Qemu-devel] [PATCH V10 01/20] filter-rewriter: Add TCP state machine and fix memory leak in connection_track_table X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: zhanghailiang , Li Zhijian , Zhang Chen Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZohoMail: RDKM_2 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" We add almost full TCP state machine in filter-rewriter, except TCPS_LISTEN and some simplify in VM active close FIN states. 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 Signed-off-by: Zhang Chen --- net/colo.c | 2 +- net/colo.h | 9 ++-- net/filter-rewriter.c | 105 ++++++++++++++++++++++++++++++++++++++---- 3 files changed, 100 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 =3D key->ip_proto; conn->processing =3D false; conn->offset =3D 0; - conn->syn_flag =3D 0; + conn->tcp_state =3D TCPS_CLOSED; conn->pack =3D 0; conn->sack =3D 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" =20 #define HASHTABLE_MAX_SIZE 16384 =20 @@ -81,11 +82,9 @@ typedef struct Connection { uint32_t sack; /* offset =3D 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=3D1,ack=3D1' */ } Connection; =20 uint32_t connection_key_hash(const void *opaque); diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c index f584e4eba4..f18a71bf2e 100644 --- a/net/filter-rewriter.c +++ b/net/filter-rewriter.c @@ -59,9 +59,9 @@ static int is_tcp_packet(Packet *pkt) } =20 /* 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; =20 @@ -74,23 +74,28 @@ static int handle_primary_tcp_pkt(NetFilterState *nf, trace_colo_filter_rewriter_conn_offset(conn->offset); } =20 + if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D (TH_ACK | TH_SYN))= && + conn->tcp_state =3D=3D TCPS_SYN_SENT) { + conn->tcp_state =3D TCPS_ESTABLISHED; + } + if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D TH_SYN)) { /* * we use this flag update offset func * run once in independent tcp connection */ - conn->syn_flag =3D 1; + conn->tcp_state =3D TCPS_SYN_RECEIVED; } =20 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D TH_ACK)) { - if (conn->syn_flag) { + if (conn->tcp_state =3D=3D TCPS_SYN_RECEIVED) { /* * offset =3D secondary_seq - primary seq * ack packet sent by guest from primary node, * so we use th_ack - 1 get primary_seq */ conn->offset -=3D (ntohl(tcp_pkt->th_ack) - 1); - conn->syn_flag =3D 0; + conn->tcp_state =3D TCPS_ESTABLISHED; } if (conn->offset) { /* handle packets to the secondary from the primary */ @@ -99,15 +104,63 @@ static int handle_primary_tcp_pkt(NetFilterState *nf, net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_le= n, pkt->size - pkt->vnet_hdr_len); } + /* + * Case 1: + * Step 3: + * The *server* side of this connect is VM, *client* tries to close + * the connection. + * + * We got 'ack=3D1' packets from client side, it acks 'fin=3D1, ac= k=3D1' + * packet from server side. From this point, we can ensure that th= ere + * will be no packets in the connection, except that, some errors + * happen between the path of 'filter object' and vNIC, if this ra= re + * case really happen, we can still create a new connection, + * So it is safe to remove the connection from connection_track_ta= ble. + * + */ + if ((conn->tcp_state =3D=3D TCPS_LAST_ACK) && + (ntohl(tcp_pkt->th_ack) =3D=3D (conn->fin_ack_seq + 1))) { + conn->tcp_state =3D TCPS_CLOSED; + g_hash_table_remove(rf->connection_track_table, key); + } + } + + if ((tcp_pkt->th_flags & TH_FIN) =3D=3D TH_FIN) { + /* + * Case 1: + * Step 1: + * The *server* side of this connect is VM, *client* tries to close + * the connection. We will into CLOSE_WAIT status. + */ + if (conn->tcp_state =3D=3D TCPS_ESTABLISHED) { + conn->tcp_state =3D TCPS_CLOSE_WAIT; + } + + /* + * Case 2: + * Step 2: + * The *server* side of this connect is VM, *server* tries to close + * the connection. We will into CLOSE_WAIT status. + * We simplify the TCPS_FIN_WAIT_2, TCPS_TIME_WAIT and CLOSING sta= tus. + */ + if (conn->tcp_state =3D=3D TCPS_FIN_WAIT_1) { + conn->tcp_state =3D TCPS_TIME_WAIT; + /* + * For simplify implementation, we needn't wait 2MSL time + * in filter rewriter. + */ + conn->tcp_state =3D TCPS_CLOSED; + g_hash_table_remove(rf->connection_track_table, key); + } } =20 return 0; } =20 /* 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; =20 @@ -121,7 +174,8 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf, trace_colo_filter_rewriter_conn_offset(conn->offset); } =20 - if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D (TH_ACK | TH_SYN))= ) { + if (conn->tcp_state =3D=3D TCPS_SYN_RECEIVED && + ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D (TH_ACK | TH_SYN))= ) { /* * save offset =3D secondary_seq and then * in handle_primary_tcp_pkt make offset @@ -130,6 +184,12 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf, conn->offset =3D ntohl(tcp_pkt->th_seq); } =20 + /* VM active connect */ + if (conn->tcp_state =3D=3D TCPS_CLOSED && + ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D TH_SYN)) { + conn->tcp_state =3D TCPS_SYN_SENT; + } + if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) =3D=3D TH_ACK) { /* Only need to adjust seq while offset is Non-zero */ if (conn->offset) { @@ -140,6 +200,31 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf, pkt->size - pkt->vnet_hdr_len); } } + /* + * Case 1: + * Step 2: + * The *server* side of this connect is VM, *client* tries to close + * the connection. In this step we will into LAST_ACK status. + * + * We got 'fin=3D1, ack=3D1' packet from server side, we need to + * record the seq of 'fin=3D1, ack=3D1' packet. + */ + if (conn->tcp_state =3D=3D TCPS_CLOSE_WAIT && + (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) =3D=3D (TH_ACK | TH_FIN)) { + conn->fin_ack_seq =3D ntohl(tcp_pkt->th_seq); + conn->tcp_state =3D TCPS_LAST_ACK; + } + + /* + * Case 2: + * Step 1: + * The *server* side of this connect is VM, *server* tries to close + * the connection. + */ + if (conn->tcp_state =3D=3D TCPS_ESTABLISHED && + (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) =3D=3D TH_FIN) { + conn->tcp_state =3D TCPS_FIN_WAIT_1; + } =20 return 0; } @@ -190,7 +275,7 @@ static ssize_t colo_rewriter_receive_iov(NetFilterState= *nf, =20 if (sender =3D=3D 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 +288,7 @@ 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); --=20 2.17.1