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[35.201.236.120]) by smtp.gmail.com with ESMTPSA id w5sm6214775pfi.74.2018.01.03.22.01.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 03 Jan 2018 22:01:44 -0800 (PST) From: Zhang Chen To: qemu devel Date: Thu, 4 Jan 2018 14:01:00 +0800 Message-Id: <1515045675-6993-2-git-send-email-zhangckid@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1515045675-6993-1-git-send-email-zhangckid@gmail.com> References: <1515045675-6993-1-git-send-email-zhangckid@gmail.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:400e:c00::243 Subject: [Qemu-devel] [PATCH RESEND V3 01/16] filter-rewriter: fix memory leak for connection 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 , Zhang Chen Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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.h | 4 +++ net/filter-rewriter.c | 69 +++++++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 66 insertions(+), 7 deletions(-) diff --git a/net/colo.h b/net/colo.h index 0658e86..0193935 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 @@ -71,6 +72,9 @@ 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 2be388f..a58310a 100644 --- a/net/filter-rewriter.c +++ b/net/filter-rewriter.c @@ -62,9 +62,9 @@ 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; @@ -102,15 +102,44 @@ 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: + * 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))) { + 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; @@ -142,8 +171,34 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf, net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len, pkt->size - pkt->vnet_hdr_len); } + /* + * 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; } @@ -193,7 +248,7 @@ 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); @@ -206,7 +261,7 @@ 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);