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[35.229.150.155]) by smtp.gmail.com with ESMTPSA id 87-v6sm14215353pfn.103.2018.07.22.12.34.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 22 Jul 2018 12:34:14 -0700 (PDT) From: Zhang Chen To: qemu-devel@nongnu.org, Paolo Bonzini , Juan Quintela , "Dr . 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 = 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..f18a71bf2e 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 +104,63 @@ 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); } + /* + * Case 1: + * Step 3: + * 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))) { + conn->tcp_state = TCPS_CLOSED; + g_hash_table_remove(rf->connection_track_table, key); + } + } + + if ((tcp_pkt->th_flags & TH_FIN) == 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 == TCPS_ESTABLISHED) { + conn->tcp_state = 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 status. + */ + 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. + */ + 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 +174,8 @@ 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 +184,12 @@ 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) { @@ -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=1, ack=1' packet from server side, we need to + * record the seq of 'fin=1, ack=1' packet. + */ + 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; + } + + /* + * Case 2: + * Step 1: + * The *server* side of this connect is VM, *server* tries to close + * the connection. + */ + 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 +275,7 @@ 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 +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);