qemu/net/filter-rewriter.c

262 lines
7.8 KiB
C

/*
* Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
* Copyright (c) 2016 FUJITSU LIMITED
* Copyright (c) 2016 Intel Corporation
*
* Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "trace.h"
#include "net/colo.h"
#include "net/filter.h"
#include "net/net.h"
#include "qemu-common.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "qapi-visit.h"
#include "qom/object.h"
#include "qemu/main-loop.h"
#include "qemu/iov.h"
#include "net/checksum.h"
#define FILTER_COLO_REWRITER(obj) \
OBJECT_CHECK(RewriterState, (obj), TYPE_FILTER_REWRITER)
#define TYPE_FILTER_REWRITER "filter-rewriter"
typedef struct RewriterState {
NetFilterState parent_obj;
NetQueue *incoming_queue;
/* hashtable to save connection */
GHashTable *connection_track_table;
} RewriterState;
static void filter_rewriter_flush(NetFilterState *nf)
{
RewriterState *s = FILTER_COLO_REWRITER(nf);
if (!qemu_net_queue_flush(s->incoming_queue)) {
/* Unable to empty the queue, purge remaining packets */
qemu_net_queue_purge(s->incoming_queue, nf->netdev);
}
}
/*
* Return 1 on success, if return 0 means the pkt
* is not TCP packet
*/
static int is_tcp_packet(Packet *pkt)
{
if (!parse_packet_early(pkt) &&
pkt->ip->ip_p == IPPROTO_TCP) {
return 1;
} else {
return 0;
}
}
/* 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)) {
trace_colo_filter_rewriter_pkt_info(__func__,
inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
tcp_pkt->th_flags);
trace_colo_filter_rewriter_conn_offset(conn->offset);
}
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;
}
if (conn->offset) {
/* 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)) {
trace_colo_filter_rewriter_pkt_info(__func__,
inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
tcp_pkt->th_flags);
trace_colo_filter_rewriter_conn_offset(conn->offset);
}
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) {
/* Only need to adjust seq while offset is Non-zero */
if (conn->offset) {
/* 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,
const struct iovec *iov,
int iovcnt,
NetPacketSent *sent_cb)
{
RewriterState *s = FILTER_COLO_REWRITER(nf);
Connection *conn;
ConnectionKey key;
Packet *pkt;
ssize_t size = iov_size(iov, iovcnt);
char *buf = g_malloc0(size);
iov_to_buf(iov, iovcnt, 0, buf, size);
pkt = packet_new(buf, size);
g_free(buf);
/*
* if we get tcp packet
* we will rewrite it to make secondary guest's
* connection established successfully
*/
if (pkt && is_tcp_packet(pkt)) {
fill_connection_key(pkt, &key);
if (sender == nf->netdev) {
/*
* We need make tcp TX and RX packet
* into one connection.
*/
reverse_connection_key(&key);
}
conn = connection_get(s->connection_track_table,
&key,
NULL);
if (sender == nf->netdev) {
/* NET_FILTER_DIRECTION_TX */
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 */
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;
}
}
}
packet_destroy(pkt, NULL);
pkt = NULL;
return 0;
}
static void colo_rewriter_cleanup(NetFilterState *nf)
{
RewriterState *s = FILTER_COLO_REWRITER(nf);
/* flush packets */
if (s->incoming_queue) {
filter_rewriter_flush(nf);
g_free(s->incoming_queue);
}
}
static void colo_rewriter_setup(NetFilterState *nf, Error **errp)
{
RewriterState *s = FILTER_COLO_REWRITER(nf);
s->connection_track_table = g_hash_table_new_full(connection_key_hash,
connection_key_equal,
g_free,
connection_destroy);
s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
}
static void colo_rewriter_class_init(ObjectClass *oc, void *data)
{
NetFilterClass *nfc = NETFILTER_CLASS(oc);
nfc->setup = colo_rewriter_setup;
nfc->cleanup = colo_rewriter_cleanup;
nfc->receive_iov = colo_rewriter_receive_iov;
}
static const TypeInfo colo_rewriter_info = {
.name = TYPE_FILTER_REWRITER,
.parent = TYPE_NETFILTER,
.class_init = colo_rewriter_class_init,
.instance_size = sizeof(RewriterState),
};
static void register_types(void)
{
type_register_static(&colo_rewriter_info);
}
type_init(register_types);