[CRIU] [PATCH 7/8] sockets: Restore in-flight unix stream sockets
Cyrill Gorcunov
gorcunov at openvz.org
Fri Jan 27 13:54:43 EST 2012
It's done in two steps
- On checkpoint we find which icons are present
over all sockets and setup peer number to
appropriate listening socket
- On restore we collect listening sockets and once
we find in-flight connection we search for appropriate
listening socket name and use it to call connect() then
Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
include/image.h | 4 +-
sockets.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 139 insertions(+), 4 deletions(-)
diff --git a/include/image.h b/include/image.h
index a7a998a..2d9c1a4 100644
--- a/include/image.h
+++ b/include/image.h
@@ -66,13 +66,15 @@ struct pipe_entry {
u8 data[0];
} __packed;
+#define USK_INFLIGHT 1
+
struct unix_sk_entry {
u32 fd;
u32 id;
u8 type;
u8 state;
u8 namelen; /* fits UNIX_PATH_MAX */
- u8 pad;
+ u8 flags;
u32 backlog;
u32 peer;
u8 name[0];
diff --git a/sockets.c b/sockets.c
index 7689b37..bd5e769 100644
--- a/sockets.c
+++ b/sockets.c
@@ -55,6 +55,19 @@ struct unix_sk_desc {
unsigned int *icons;
};
+struct unix_sk_listen_icon {
+ unsigned int peer_ino;
+ struct unix_sk_desc *sk_desc;
+ struct unix_sk_listen_icon *next;
+};
+
+struct unix_sk_listen {
+ unsigned int ino;
+ struct sockaddr_un addr;
+ unsigned int addrlen;
+ struct unix_sk_listen *next;
+};
+
#define INET_ADDR_LEN 40
struct inet_sk_desc {
@@ -75,6 +88,7 @@ struct inet_sk_desc {
(elem)->next = (head)[(key) % SK_HASH_SIZE]; \
(head)[(key) % SK_HASH_SIZE] = (elem); \
} while (0)
+
#define __gen_static_lookup_func(ret, name, head, _member, _type, _name)\
static ret *name(_type _name) { \
ret *d; \
@@ -88,6 +102,18 @@ struct inet_sk_desc {
static struct socket_desc *sockets[SK_HASH_SIZE];
__gen_static_lookup_func(struct socket_desc, lookup_socket, sockets, ino, int, ino);
+static struct unix_sk_listen_icon *unix_listen_icons[SK_HASH_SIZE];
+__gen_static_lookup_func(struct unix_sk_listen_icon, \
+ lookup_unix_listen_icons, \
+ unix_listen_icons, \
+ peer_ino, unsigned int, ino);
+
+static struct unix_sk_listen *unix_listen[SK_HASH_SIZE];
+__gen_static_lookup_func(struct unix_sk_listen, \
+ lookup_unix_listen, \
+ unix_listen, \
+ ino, unsigned int, ino);
+
static int sk_collect_one(int ino, int family, struct socket_desc *d)
{
d->ino = ino;
@@ -262,9 +288,39 @@ static int dump_one_unix(struct socket_desc *_sk, int fd, struct cr_fdset *cr_fd
ue.namelen = sk->namelen;
ue.backlog = sk->wqlen;
- ue.pad = 0;
+ ue.flags = 0;
ue.peer = sk->peer_ino;
+ /*
+ * If this is in-flight connection we need to figure
+ * out where to connect it on restore. Thus, tune up peer
+ * id by searching an existing listening socket.
+ *
+ * Note the socket name will be found at restore stage,
+ * not now, just to reduce size of dump files.
+ */
+ if (!ue.peer && ue.state == TCP_ESTABLISHED) {
+ struct unix_sk_listen_icon *e;
+
+ e = lookup_unix_listen_icons(ue.id);
+ if (!e) {
+ pr_err("Dangling in-flight connection %d\n", ue.id);
+ goto err;
+ }
+
+ /* e->sk_desc is _never_ NULL */
+ if (e->sk_desc->state != TCP_LISTEN) {
+ pr_err("In-flight connection on "
+ "non-listening socket %d\n", ue.id);
+ goto err;
+ }
+
+ ue.flags |= USK_INFLIGHT;
+ ue.peer = e->sk_desc->sd.ino;
+
+ dprintk("\t\tFixed inflight socket %d peer %d)\n", ue.id, ue.peer);
+ }
+
if (write_img(cr_fdset->fds[CR_FD_UNIXSK], &ue))
goto err;
if (write_img_buf(cr_fdset->fds[CR_FD_UNIXSK], sk->name, ue.namelen))
@@ -421,6 +477,7 @@ static int unix_collect_one(struct unix_diag_msg *m, struct rtattr **tb)
if (tb[UNIX_DIAG_ICONS]) {
int len = RTA_PAYLOAD(tb[UNIX_DIAG_ICONS]);
+ int i;
d->icons = xmalloc(len);
if (!d->icons)
@@ -428,6 +485,28 @@ static int unix_collect_one(struct unix_diag_msg *m, struct rtattr **tb)
memcpy(d->icons, RTA_DATA(tb[UNIX_DIAG_ICONS]), len);
d->nr_icons = len / sizeof(u32);
+
+ /*
+ * Remember these sockets, we will need them
+ * to fix up in-flight sockets peers.
+ */
+ for (i = 0; i < d->nr_icons; i++) {
+ struct unix_sk_listen_icon *e;
+ int n;
+
+ e = xzalloc(sizeof(*e));
+ if (!e)
+ goto err;
+
+ SK_HASH_LINK(unix_listen_icons, d->icons[i], e);
+
+ dprintk("\t\tCollected icon %d\n", d->icons[i]);
+
+ e->peer_ino = d->icons[i];
+ e->sk_desc = d;
+ }
+
+
}
if (tb[UNIX_DIAG_RQLEN]) {
@@ -589,6 +668,7 @@ static struct unix_conn_job *conn_jobs;
static int run_connect_jobs(void)
{
struct unix_conn_job *cj, *next;
+ int i;
cj = conn_jobs;
while (cj) {
@@ -612,6 +692,20 @@ try_again:
cj = next;
}
+ /*
+ * Free collected listening sockets,
+ * we don't need them anymore.
+ */
+ for (i = 0; i < SK_HASH_SIZE; i++) {
+ struct unix_sk_listen *h = unix_listen[i];
+ struct unix_sk_listen *e;
+ while (h) {
+ e = h->next;
+ xfree(h);
+ h = e;
+ }
+ }
+
return 0;
}
@@ -795,6 +889,7 @@ static int open_unix_sk_stream(int sk, struct unix_sk_entry *ue, int img_fd)
if (ue->state == TCP_LISTEN) {
struct sockaddr_un addr;
+ struct unix_sk_listen *e;
int ret;
/*
@@ -827,6 +922,24 @@ static int open_unix_sk_stream(int sk, struct unix_sk_entry *ue, int img_fd)
pr_perror("Can't listen socket\n");
goto err;
}
+
+ /*
+ * Collect listening sockets here, we will
+ * need them to resolve in-flight connections
+ * names.
+ */
+ e = xzalloc(sizeof(*e));
+ if (!e)
+ goto err;
+
+ SK_HASH_LINK(unix_listen, ue->id, e);
+
+ memcpy(&e->addr, &addr, sizeof(e->addr));
+ e->addrlen = sizeof(e->addr.sun_family) + ue->namelen;
+ e->ino = ue->id;
+
+ dprintk("\t\Collected listening socket %d\n", ue->id);
+
} else if (ue->state == TCP_ESTABLISHED) {
/*
@@ -838,7 +951,7 @@ static int open_unix_sk_stream(int sk, struct unix_sk_entry *ue, int img_fd)
* deferred to connect() later.
*/
- if (ue->peer < ue->id) {
+ if (ue->peer < ue->id && !(ue->flags & USK_INFLIGHT)) {
struct sockaddr_un addr;
int len;
struct unix_accept_job *aj;
@@ -877,7 +990,27 @@ static int open_unix_sk_stream(int sk, struct unix_sk_entry *ue, int img_fd)
if (!cj)
goto err;
- prep_conn_addr(ue->peer, &cj->addr, &cj->addrlen);
+ /*
+ * Might need to resolve in-flight connection name.
+ */
+ if (ue->flags & USK_INFLIGHT) {
+ struct unix_sk_listen *e;
+
+ /*
+ * Find out listening sockets name.
+ */
+ e = lookup_unix_listen(ue->peer);
+ if (!e) {
+ pr_err("Bad in-flight socket peer %d\n",
+ ue->peer);
+ goto err;
+ }
+
+ memcpy(&cj->addr, &e->addr, sizeof(cj->addr));
+ cj->addrlen = e->addrlen;
+ } else
+ prep_conn_addr(ue->peer, &cj->addr, &cj->addrlen);
+
cj->fd = ue->fd;
cj->next = conn_jobs;
conn_jobs = cj;
--
1.7.7.5
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