diff options
Diffstat (limited to 'net/filter-rewriter.c')
| -rw-r--r-- | net/filter-rewriter.c | 109 |
1 files changed, 99 insertions, 10 deletions
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); |