| Message ID | 20180603050546.6827-2-zhangckid@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2018年06月03日 13:05, Zhang Chen wrote: > 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.zhanghailiang@huawei.com> > Signed-off-by: Zhang Chen <zhangckid@gmail.com> > --- > 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 da6c36dcf7..cd118510c5 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 > > @@ -86,6 +87,9 @@ 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' */ So the question is, the state machine is not complete. I suspect there will be corner cases that will be left because of lacking sufficient states. LAST_ACK happens only for passive close. How about active close? So I think we need either maintain a full state machine or not instead of a partial one. We don't want endless bugs. Thanks > } Connection; > > uint32_t connection_key_hash(const void *opaque); > diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c > index 62dad2d773..0909a9a8af 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; > > @@ -99,15 +99,44 @@ 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; > > @@ -139,8 +168,34 @@ 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; > } > > @@ -190,7 +245,7 @@ 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 +258,7 @@ 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);
On Mon, Jun 4, 2018 at 1:51 PM, Jason Wang <jasowang@redhat.com> wrote: > > > On 2018年06月03日 13:05, Zhang Chen wrote: > >> 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.zhanghailiang@huawei.com> >> Signed-off-by: Zhang Chen <zhangckid@gmail.com> >> --- >> 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 da6c36dcf7..cd118510c5 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 >> @@ -86,6 +87,9 @@ 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' */ >> > > So the question is, the state machine is not complete. I suspect there > will be corner cases that will be left because of lacking sufficient > states. LAST_ACK happens only for passive close. How about active close? > > So I think we need either maintain a full state machine or not instead of > a partial one. We don't want endless bugs. > OK, I got it. I will add a full state machine here in next version. Thanks Zhang Chen > > Thanks > > > } Connection; >> uint32_t connection_key_hash(const void *opaque); >> diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c >> index 62dad2d773..0909a9a8af 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; >> @@ -99,15 +99,44 @@ 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; >> @@ -139,8 +168,34 @@ 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; >> } >> @@ -190,7 +245,7 @@ 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 +258,7 @@ 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); >> > >
diff --git a/net/colo.h b/net/colo.h index da6c36dcf7..cd118510c5 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 @@ -86,6 +87,9 @@ 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 62dad2d773..0909a9a8af 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; @@ -99,15 +99,44 @@ 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; @@ -139,8 +168,34 @@ 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; } @@ -190,7 +245,7 @@ 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 +258,7 @@ 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);