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[Qemu-devel] [PULL 12/27] filter-rewriter: rewrite tcp packet to keep se
From: |
Jason Wang |
Subject: |
[Qemu-devel] [PULL 12/27] filter-rewriter: rewrite tcp packet to keep secondary connection |
Date: |
Mon, 26 Sep 2016 16:59:20 +0800 |
From: Zhang Chen <address@hidden>
We will rewrite tcp packet secondary received and sent.
When colo guest is a tcp server.
Firstly, client start a tcp handshake. the packet's seq=client_seq,
ack=0,flag=SYN. COLO primary guest get this pkt and mirror(filter-mirror)
to secondary guest, secondary get it use filter-redirector.
Then,primary guest response pkt
(seq=primary_seq,ack=client_seq+1,flag=ACK|SYN).
secondary guest response pkt
(seq=secondary_seq,ack=client_seq+1,flag=ACK|SYN).
In here,we use filter-rewriter save the secondary_seq to it's tcp connection.
Finally handshake,client send pkt
(seq=client_seq+1,ack=primary_seq+1,flag=ACK).
Here,filter-rewriter can get primary_seq, and rewrite ack from primary_seq+1
to secondary_seq+1, recalculate checksum. So the secondary tcp connection
kept good.
When we send/recv packet.
client send pkt(seq=client_seq+1+data_len,ack=primary_seq+1,flag=ACK|PSH).
filter-rewriter rewrite ack and send to secondary guest.
primary guest response pkt
(seq=primary_seq+1,ack=client_seq+1+data_len,flag=ACK)
secondary guest response pkt
(seq=secondary_seq+1,ack=client_seq+1+data_len,flag=ACK)
we rewrite secondary guest seq from secondary_seq+1 to primary_seq+1.
So tcp connection kept good.
In code We use offset( = secondary_seq - primary_seq )
to rewrite seq or ack.
handle_primary_tcp_pkt: tcp_pkt->th_ack += offset;
handle_secondary_tcp_pkt: tcp_pkt->th_seq -= offset;
Signed-off-by: Zhang Chen <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
Signed-off-by: Wen Congyang <address@hidden>
Signed-off-by: Jason Wang <address@hidden>
---
net/colo.c | 2 +
net/colo.h | 7 ++++
net/filter-rewriter.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++-
trace-events | 5 +++
4 files changed, 124 insertions(+), 2 deletions(-)
diff --git a/net/colo.c b/net/colo.c
index dc4e4a4..9f469e6 100644
--- a/net/colo.c
+++ b/net/colo.c
@@ -135,6 +135,8 @@ Connection *connection_new(ConnectionKey *key)
conn->ip_proto = key->ip_proto;
conn->processing = false;
+ conn->offset = 0;
+ conn->syn_flag = 0;
g_queue_init(&conn->primary_list);
g_queue_init(&conn->secondary_list);
diff --git a/net/colo.h b/net/colo.h
index 6720a3a..7c524f3 100644
--- a/net/colo.h
+++ b/net/colo.h
@@ -62,6 +62,13 @@ typedef struct Connection {
/* flag to enqueue unprocessed_connections */
bool processing;
uint8_t ip_proto;
+ /* offset = secondary_seq - primary_seq */
+ tcp_seq offset;
+ /*
+ * we use this flag update offset func
+ * run once in independent tcp connection
+ */
+ int syn_flag;
} Connection;
uint32_t connection_key_hash(const void *opaque);
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
index 1d49d04..cd0dc54 100644
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -10,6 +10,7 @@
*/
#include "qemu/osdep.h"
+#include "trace.h"
#include "net/colo.h"
#include "net/filter.h"
#include "net/net.h"
@@ -58,6 +59,93 @@ static int is_tcp_packet(Packet *pkt)
}
}
+/* handle tcp packet from primary guest */
+static int handle_primary_tcp_pkt(NetFilterState *nf,
+ Connection *conn,
+ Packet *pkt)
+{
+ struct tcphdr *tcp_pkt;
+
+ tcp_pkt = (struct tcphdr *)pkt->transport_header;
+ if (trace_event_get_state(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
+ char *sdebug, *ddebug;
+ sdebug = strdup(inet_ntoa(pkt->ip->ip_src));
+ ddebug = strdup(inet_ntoa(pkt->ip->ip_dst));
+ trace_colo_filter_rewriter_pkt_info(__func__, sdebug, ddebug,
+ ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
+ tcp_pkt->th_flags);
+ trace_colo_filter_rewriter_conn_offset(conn->offset);
+ g_free(sdebug);
+ g_free(ddebug);
+ }
+
+ 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;
+ }
+
+ if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK)) {
+ if (conn->syn_flag) {
+ /*
+ * 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;
+ }
+ /* handle packets to the secondary from the primary */
+ tcp_pkt->th_ack = htonl(ntohl(tcp_pkt->th_ack) + conn->offset);
+
+ net_checksum_calculate((uint8_t *)pkt->data, pkt->size);
+ }
+
+ return 0;
+}
+
+/* handle tcp packet from secondary guest */
+static int handle_secondary_tcp_pkt(NetFilterState *nf,
+ Connection *conn,
+ Packet *pkt)
+{
+ struct tcphdr *tcp_pkt;
+
+ tcp_pkt = (struct tcphdr *)pkt->transport_header;
+
+ if (trace_event_get_state(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
+ char *sdebug, *ddebug;
+ sdebug = strdup(inet_ntoa(pkt->ip->ip_src));
+ ddebug = strdup(inet_ntoa(pkt->ip->ip_dst));
+ trace_colo_filter_rewriter_pkt_info(__func__, sdebug, ddebug,
+ ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
+ tcp_pkt->th_flags);
+ trace_colo_filter_rewriter_conn_offset(conn->offset);
+ g_free(sdebug);
+ g_free(ddebug);
+ }
+
+ if (((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
+ * = secondary_seq - primary_seq
+ */
+ conn->offset = ntohl(tcp_pkt->th_seq);
+ }
+
+ if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK) {
+ /* handle packets to the primary from the secondary*/
+ tcp_pkt->th_seq = htonl(ntohl(tcp_pkt->th_seq) - conn->offset);
+
+ net_checksum_calculate((uint8_t *)pkt->data, pkt->size);
+ }
+
+ return 0;
+}
+
static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
NetClientState *sender,
unsigned flags,
@@ -97,10 +185,30 @@ static ssize_t colo_rewriter_receive_iov(NetFilterState
*nf,
if (sender == nf->netdev) {
/* NET_FILTER_DIRECTION_TX */
- /* handle_primary_tcp_pkt */
+ if (!handle_primary_tcp_pkt(nf, conn, pkt)) {
+ qemu_net_queue_send(s->incoming_queue, sender, 0,
+ (const uint8_t *)pkt->data, pkt->size, NULL);
+ packet_destroy(pkt, NULL);
+ pkt = NULL;
+ /*
+ * We block the packet here,after rewrite pkt
+ * and will send it
+ */
+ return 1;
+ }
} else {
/* NET_FILTER_DIRECTION_RX */
- /* handle_secondary_tcp_pkt */
+ if (!handle_secondary_tcp_pkt(nf, conn, pkt)) {
+ qemu_net_queue_send(s->incoming_queue, sender, 0,
+ (const uint8_t *)pkt->data, pkt->size, NULL);
+ packet_destroy(pkt, NULL);
+ pkt = NULL;
+ /*
+ * We block the packet here,after rewrite pkt
+ * and will send it
+ */
+ return 1;
+ }
}
}
diff --git a/trace-events b/trace-events
index b395368..1cb9d37 100644
--- a/trace-events
+++ b/trace-events
@@ -150,6 +150,11 @@ colo_compare_ip_info(int psize, const char *sta, const
char *stb, int ssize, con
colo_old_packet_check_found(int64_t old_time) "%" PRId64
colo_compare_miscompare(void) ""
+# net/filter-rewriter.c
+colo_filter_rewriter_debug(void) ""
+colo_filter_rewriter_pkt_info(const char *func, const char *src, const char
*dst, uint32_t seq, uint32_t ack, uint32_t flag) "%s: src/dst: %s/%s p:
seq/ack=%u/%u flags=%x\n"
+colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u\n"
+
### Guest events, keep at bottom
# @vaddr: Access' virtual address.
--
2.7.4
- [Qemu-devel] [PULL 02/27] net: hmp_host_net_remove: Del the -net option of the removed host_net, (continued)
- [Qemu-devel] [PULL 02/27] net: hmp_host_net_remove: Del the -net option of the removed host_net, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 03/27] qemu-char: Add qemu_chr_add_handlers_full() for GMaincontext, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 05/27] net/colo.c: add colo.c to define and handle packet, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 04/27] colo-compare: introduce colo compare initialization, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 06/27] Jhash: add linux kernel jhashtable in qemu, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 07/27] colo-compare: track connection and enqueue packet, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 08/27] colo-compare: introduce packet comparison thread, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 09/27] colo-compare: add TCP, UDP, ICMP packet comparison, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 10/27] filter-rewriter: introduce filter-rewriter initialization, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 11/27] filter-rewriter: track connection and parse packet, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 12/27] filter-rewriter: rewrite tcp packet to keep secondary connection,
Jason Wang <=
- [Qemu-devel] [PULL 13/27] MAINTAINERS: add maintainer for COLO-proxy, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 14/27] docs: Add documentation for COLO-proxy, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 15/27] e1000: fix buliding complaint, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 16/27] tap: Allow specifying a bridge, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 18/27] e1000e: Flush all receive queues on receive enable, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 17/27] net: limit allocation in nc_sendv_compat, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 19/27] e1000e: Flush receive queues on link up, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 20/27] e1000e: Fix CTRL_EXT.EIAME behavior, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 23/27] e1000e: Fix spurious RX TCP ACK interrupts, Jason Wang, 2016/09/26
- [Qemu-devel] [PULL 21/27] e1000e: Fix PBACLR implementation, Jason Wang, 2016/09/26