diff options
Diffstat (limited to 'net/filter-rewriter.c')
| -rw-r--r-- | net/filter-rewriter.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c new file mode 100644 index 0000000000..89abe72d4e --- /dev/null +++ b/net/filter-rewriter.c @@ -0,0 +1,263 @@ +/* + * 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)) { + 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, + 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); + + /* + * 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); |