On 2016年06月14日 19:15, Zhang Chen wrote:
We will rewrite tcp packet secondary received and sent.
More verbose please. E.g which fields were rewrote and why.
Signed-off-by: Zhang Chen <zhangchen.f...@cn.fujitsu.com>
Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com>
Signed-off-by: Wen Congyang <we...@cn.fujitsu.com>
---
net/filter-rewriter.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++--
trace-events | 3 ++
2 files changed, 95 insertions(+), 2 deletions(-)
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
index 12f88c5..86a2f53 100644
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -21,6 +21,7 @@
#include "qemu/main-loop.h"
#include "qemu/iov.h"
#include "net/checksum.h"
+#include "trace.h"
#define FILTER_COLO_REWRITER(obj) \
OBJECT_CHECK(RewriterState, (obj), TYPE_FILTER_REWRITER)
@@ -64,6 +65,75 @@ static int is_tcp_packet(Packet *pkt)
}
}
+static int handle_primary_tcp_pkt(NetFilterState *nf,
+ Connection *conn,
+ Packet *pkt)
+{
+ struct tcphdr *tcp_pkt;
+
+ tcp_pkt = (struct tcphdr *)pkt->transport_layer;
+
+ if (trace_event_get_state(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
Why not use tracepoints directly?
+ char *sdebug, *ddebug;
+ sdebug = strdup(inet_ntoa(pkt->ip->ip_src));
+ ddebug = strdup(inet_ntoa(pkt->ip->ip_dst));
+ fprintf(stderr, "%s: src/dst: %s/%s p: seq/ack=%u/%u"
+ " flags=%x\n", __func__, sdebug, ddebug,
+ ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
+ tcp_pkt->th_flags);
+ g_free(sdebug);
+ g_free(ddebug);
+ }
+
+ if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK)) {
+ /* save primary colo tcp packet seq */
+ conn->primary_seq = ntohl(tcp_pkt->th_ack) - 1;
Looks like primary_seq will only be updated during handshake, I wonder
how this works.
+
+ /* adjust tcp seq to make secondary guest handle it */
+ tcp_pkt->th_ack = htonl(conn->secondary_seq + 1);
I'm not sure this can work for all cases. I believe we should also
rewrite seq here. And to me, a better approach is to track the offset of
seq between pri and sec during handshake and rewrite both ack and seq
based on this offset.
+ net_checksum_calculate((uint8_t *)pkt->data, pkt->size);
+ }
+
+ return 0;
+}
+
+static int handle_secondary_tcp_pkt(NetFilterState *nf,
+ Connection *conn,
+ Packet *pkt)
+{
+ struct tcphdr *tcp_pkt;
+
+ tcp_pkt = (struct tcphdr *)pkt->transport_layer;
+
+ 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));
+ printf("handle_secondary_tcp_pkt conn->secondary_seq = %u,\n",
+ conn->secondary_seq);
+ printf("handle_secondary_tcp_pkt conn->primary_seq = %u,\n",
+ conn->primary_seq);
+ fprintf(stderr, "%s: src/dst: %s/%s p: seq/ack=%u/%u"
+ " flags=%x\n", __func__, sdebug, ddebug,
+ ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
+ tcp_pkt->th_flags);
+ g_free(sdebug);
+ g_free(ddebug);
+ }
+
+ if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) {
+ /* save client's seq */
+ conn->secondary_seq = ntohl(tcp_pkt->th_seq);
+ }
+
+ if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK) {
+ tcp_pkt->th_seq = htonl(conn->primary_seq + 1);
+ net_checksum_calculate((uint8_t *)pkt->data, pkt->size);
+ }
+
+ return 0;
+}
+
static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
NetClientState *sender,
unsigned flags,
@@ -106,10 +176,30 @@ static ssize_t colo_rewriter_receive_iov(NetFilterState
*nf,
if (sender == nf->netdev) {
/* This packet is sent by netdev itself */
/* 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 6686cdf..5d798c6 100644
--- a/trace-events
+++ b/trace-events
@@ -1927,3 +1927,6 @@ colo_compare_icmp_miscompare_mtu(const char *sta, int size) ":
%s %d"
colo_compare_ip_info(int psize, const char *sta, const char *stb, int ssize, const char
*stc, const char *std) "ppkt size = %d, ip_src = %s, ip_dst = %s, spkt size = %d,
ip_src = %s, ip_dst = %s"
colo_old_packet_check_found(int64_t old_time) "%" PRId64
colo_compare_miscompare(void) ""
+
+# net/filter-rewriter.c
+colo_filter_rewriter_debug(void) ""
