[CRIU] [PATCH 03/11] soccr: add support for half-closed sockets
Andrei Vagin
avagin at openvz.org
Thu Nov 10 23:10:03 PST 2016
From: Andrei Vagin <avagin at virtuozzo.com>
A socket is in one of half-closed states, if it sent a fin packet
or it received a fin packet.
CRIU plays with fin packets to restore half-closed states too.
When we need to sent a fin packet from a socket, we can call
shutdown(SHUT_WR). When a fin packet has to be restore in
a received queue, criu generate a fin packet and send it via
a raw ip socket.
A raw packet is sent with the SOCCR_MARK mark to be able
to not block it.
Signed-off-by: Andrei Vagin <avagin at virtuozzo.com>
---
criu/Makefile.packages | 2 +-
soccr/soccr.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++++-
soccr/soccr.h | 18 +++++-
3 files changed, 180 insertions(+), 5 deletions(-)
diff --git a/criu/Makefile.packages b/criu/Makefile.packages
index 53fbdae..886394f 100644
--- a/criu/Makefile.packages
+++ b/criu/Makefile.packages
@@ -19,7 +19,7 @@ REQ-DEB-PKG-NAMES += libcap-dev
REQ-DEB-PKG-TEST-NAMES += libaio-dev
-export LIBS += -lrt -lpthread -lprotobuf-c -ldl -lnl-3 -lsoccr -Lsoccr/
+export LIBS += -lrt -lpthread -lprotobuf-c -ldl -lnl-3 -lsoccr -Lsoccr/ -lnet
check-packages-failed:
$(warning Can not find some of the required libraries)
diff --git a/soccr/soccr.c b/soccr/soccr.c
index 7c6bfb1..af39eda 100644
--- a/soccr/soccr.c
+++ b/soccr/soccr.c
@@ -4,6 +4,9 @@
#include <sys/ioctl.h>
#include <errno.h>
#include <linux/sockios.h>
+#include <libnet.h>
+#include <assert.h>
+
#include "soccr.h"
#ifndef SIOCOUTQNSD
@@ -11,6 +14,20 @@
#define SIOCOUTQNSD 0x894B
#endif
+enum {
+ TCPF_ESTABLISHED = (1 << 1),
+ TCPF_SYN_SENT = (1 << 2),
+ TCPF_SYN_RECV = (1 << 3),
+ TCPF_FIN_WAIT1 = (1 << 4),
+ TCPF_FIN_WAIT2 = (1 << 5),
+ TCPF_TIME_WAIT = (1 << 6),
+ TCPF_CLOSE = (1 << 7),
+ TCPF_CLOSE_WAIT = (1 << 8),
+ TCPF_LAST_ACK = (1 << 9),
+ TCPF_LISTEN = (1 << 10),
+ TCPF_CLOSING = (1 << 11),
+};
+
static void (*log)(unsigned int loglevel, const char *format, ...)
__attribute__ ((__format__ (__printf__, 2, 3)));
static unsigned int log_level = 0;
@@ -89,6 +106,11 @@ static int refresh_sk(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, str
switch (ti->tcpi_state) {
case TCP_ESTABLISHED:
+ case TCP_FIN_WAIT1:
+ case TCP_FIN_WAIT2:
+ case TCP_LAST_ACK:
+ case TCP_CLOSE_WAIT:
+ case TCP_CLOSING:
case TCP_CLOSE:
break;
default:
@@ -96,7 +118,7 @@ static int refresh_sk(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, str
return -1;
}
- data->state = TCP_ESTABLISHED;
+ data->state = ti->tcpi_state;
if (ioctl(sk->fd, SIOCOUTQ, &size) == -1) {
loge("Unable to get size of snd queue");
@@ -112,6 +134,14 @@ static int refresh_sk(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, str
data->unsq_len = size;
+ /* Don't account the fin packet. It doesn't countain real data. */
+ if ((1 << data->state) & (TCPF_FIN_WAIT1 | TCPF_LAST_ACK | TCPF_CLOSING)) {
+ assert(data->outq_len > 0);
+ data->outq_len--;
+ data->unsq_len = data->unsq_len ? data->unsq_len - 1 : 0;
+ }
+
+
if (ioctl(sk->fd, SIOCINQ, &size) == -1) {
loge("Unable to get size of recv queue");
return -1;
@@ -325,12 +355,22 @@ static int set_queue_seq(struct libsoccr_sk *sk, int queue, __u32 seq)
int libsoccr_set_sk_data_unbound(struct libsoccr_sk *sk,
struct libsoccr_sk_data *data, unsigned data_size)
{
+ int mstate = 1 << data->state;
+
if (!data || data_size < SOCR_DATA_MIN_SIZE)
return -1;
- if (data->state != TCP_ESTABLISHED)
+ if (data->state == TCP_LISTEN)
return -1;
+ if (mstate & (TCPF_CLOSE_WAIT | TCPF_LAST_ACK | TCPF_CLOSE))
+ data->inq_seq--;
+
+ /* outq_seq is adjusted due to not accointing the fin packet */
+ if (mstate & (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 |
+ TCPF_LAST_ACK | TCPF_CLOSING | TCPF_CLOSE))
+ data->outq_seq--;
+
if (set_queue_seq(sk, TCP_RECV_QUEUE,
data->inq_seq - data->inq_len))
return -2;
@@ -400,6 +440,98 @@ int libsoccr_set_sk_data_noq(struct libsoccr_sk *sk,
return 0;
}
+static int send_fin(int sk, struct libsoccr_sk_data *data, unsigned data_size)
+{
+ int ret, exit_code = -1;
+ char errbuf[LIBNET_ERRBUF_SIZE];
+ int mark = SOCCR_MARK;;
+ int libnet_type;
+ libnet_t *l;
+
+ libnet_type = data->family == AF_INET6 ? LIBNET_RAW6 : LIBNET_RAW4;
+
+ l = libnet_init(
+ libnet_type, /* injection type */
+ NULL, /* network interface */
+ errbuf); /* errbuf */
+ if (l == NULL)
+ return -1;
+
+ if (setsockopt(l->fd, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)))
+ goto err;
+
+ ret = libnet_build_tcp(
+ data->dst_port, /* source port */
+ data->src_port, /* destination port */
+ data->inq_seq, /* sequence number */
+ data->outq_seq - data->outq_len, /* acknowledgement num */
+ TH_FIN | TH_ACK, /* control flags */
+ data->rcv_wnd, /* window size */
+ 0, /* checksum */
+ 10, /* urgent pointer */
+ LIBNET_TCP_H + 20, /* TCP packet size */
+ NULL, /* payload */
+ 0, /* payload size */
+ l, /* libnet handle */
+ 0); /* libnet id */
+ if (ret == -1) {
+ loge("Can't build TCP header: %s\n", libnet_geterror(l));
+ goto err;
+ }
+
+ if (data->family == AF_INET6) {
+ struct libnet_in6_addr src, dst;
+
+ memcpy(&dst, data->dst_addr, sizeof(dst));
+ memcpy(&src, data->src_addr, sizeof(src));
+
+ ret = libnet_build_ipv6(
+ 0, 0,
+ LIBNET_TCP_H, /* length */
+ IPPROTO_TCP, /* protocol */
+ 64, /* hop limit */
+ dst, /* source IP */
+ src, /* destination IP */
+ NULL, /* payload */
+ 0, /* payload size */
+ l, /* libnet handle */
+ 0); /* libnet id */
+ } else if (data->family == AF_INET)
+ ret = libnet_build_ipv4(
+ LIBNET_IPV4_H + LIBNET_TCP_H + 20, /* length */
+ 0, /* TOS */
+ 242, /* IP ID */
+ 0, /* IP Frag */
+ 64, /* TTL */
+ IPPROTO_TCP, /* protocol */
+ 0, /* checksum */
+ data->dst_addr[0], /* source IP */
+ data->src_addr[0], /* destination IP */
+ NULL, /* payload */
+ 0, /* payload size */
+ l, /* libnet handle */
+ 0); /* libnet id */
+ else {
+ loge("Unknown socket family");
+ goto err;
+ }
+ if (ret == -1) {
+ loge("Can't build IP header: %s\n", libnet_geterror(l));
+ goto err;
+ }
+
+ ret = libnet_write(l);
+ if (ret == -1) {
+ loge("Unable to send a fin packet: %s", libnet_geterror(l));
+ goto err;
+ }
+
+ exit_code = 0;
+err:
+ libnet_destroy(l);
+ return exit_code;
+}
+
int libsoccr_set_sk_data(struct libsoccr_sk *sk,
struct libsoccr_sk_data *data, unsigned data_size)
{
@@ -411,13 +543,40 @@ int libsoccr_set_sk_data(struct libsoccr_sk *sk,
.rcv_wnd = data->rcv_wnd,
.rcv_wup = data->rcv_wup,
};
-
+
+ if ((1 << data->state) & ((1 << TCP_CLOSE_WAIT) |
+ (1 << TCP_LAST_ACK) |
+ (1 << TCP_CLOSE))) {
+ wopt.rcv_wup--;
+ wopt.rcv_wnd++;
+ }
+
if (setsockopt(sk->fd, SOL_TCP, TCP_REPAIR_WINDOW, &wopt, sizeof(wopt))) {
loge("Unable to set window parameters");
return -1;
}
}
+ if (data->flags & SOCCR_FLAGS_ADDR) {
+ int mstate = 1 << data->state;
+
+ if (data->state == TCP_CLOSING) {
+ shutdown(sk->fd, SHUT_WR);
+ }
+ if (mstate & (TCPF_CLOSE_WAIT | TCPF_LAST_ACK | TCPF_CLOSE)) {
+ if (send_fin(sk->fd, data, data_size) < 0)
+ return -1;
+ }
+
+ if (mstate & (TCPF_LAST_ACK | TCPF_FIN_WAIT1 |
+ TCPF_FIN_WAIT2 | TCPF_CLOSE)) {
+ shutdown(sk->fd, SHUT_WR);
+ }
+ } else if (data->state != TCP_ESTABLISHED) {
+ loge("Unable to restore a socket state: %d", data->state);
+ return -1;
+ }
+
return 0;
}
diff --git a/soccr/soccr.h b/soccr/soccr.h
index 4e272d5..a3a950b 100644
--- a/soccr/soccr.h
+++ b/soccr/soccr.h
@@ -5,6 +5,9 @@
#include "config.h"
+/* All packets with this mark have not to be blocked. */
+#define SOCCR_MARK 0xC114
+
#ifndef CONFIG_HAS_TCP_REPAIR_WINDOW
struct tcp_repair_window {
uint32_t snd_wl1;
@@ -75,11 +78,18 @@ struct libsoccr_sk_data {
__u32 timestamp;
__u32 flags; /* SOCCR_FLAGS_... below */
- __u32 snd_wl1;
+
+ __u32 snd_wl1; /* SOCCR_FLAGS_WINDOW */
__u32 snd_wnd;
__u32 max_window;
__u32 rcv_wnd;
__u32 rcv_wup;
+
+ __u32 family; /* SOCCR_FLAGS_ADDR */
+ __u32 src_port;
+ __u32 dst_port;
+ __u32 src_addr[4];
+ __u32 dst_addr[4];
};
/*
@@ -99,6 +109,12 @@ struct libsoccr_sk_data {
#define SOCCR_FLAGS_WINDOW 0x1
/*
+ * Source and destination addresses, which are required to restore
+ * a socket state.
+ */
+#define SOCCR_FLAGS_ADDR 0x2
+
+/*
* These two calls pause and resume the socket for and after C/R
* The first one returns an opaque handle that is to be used by all
* the subsequent calls.
--
2.7.4
More information about the CRIU
mailing list