Quoting Dan Smith ([email protected]):
> This is an incremental step towards supporting checkpoint/restart on
> AF_INET sockets. In this scenario, any sockets that were in TCP_LISTEN
> state are restored as they were. Any that were connected are forced to
> TCP_CLOSE. This should cover a range of use cases that involve
> applications that are tolerant of such an interruption.
>
> Cc: Oren Laadan <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Signed-off-by: Dan Smith <[email protected]>
> ---
> include/linux/checkpoint_hdr.h | 11 ++
> include/net/inet_common.h | 9 ++
> net/checkpoint.c | 9 ++
> net/ipv4/Makefile | 1 +
> net/ipv4/af_inet.c | 6 +
> net/ipv4/checkpoint.c | 204
> ++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 240 insertions(+), 0 deletions(-)
> create mode 100644 net/ipv4/checkpoint.c
>
> diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
> index 2ed523f..b5ce115 100644
> --- a/include/linux/checkpoint_hdr.h
> +++ b/include/linux/checkpoint_hdr.h
> @@ -15,9 +15,11 @@
> #ifdef __KERNEL__
> #include <linux/socket.h>
> #include <linux/un.h>
> +#include <linux/in.h>
> #else
> #include <sys/socket.h>
> #include <sys/un.h>
> +#include <sys/in.h>
> #endif
>
> /*
> @@ -106,6 +108,7 @@ enum {
> CKPT_HDR_SOCKET_QUEUE,
> CKPT_HDR_SOCKET_BUFFER,
> CKPT_HDR_SOCKET_UNIX,
> + CKPT_HDR_SOCKET_INET,
>
> CKPT_HDR_TAIL = 9001,
>
> @@ -470,6 +473,14 @@ struct ckpt_hdr_socket_unix {
> struct sockaddr_un raddr;
> } __attribute__ ((aligned(8)));
>
> +struct ckpt_hdr_socket_inet {
> + struct ckpt_hdr h;
> + __u32 laddr_len;
> + __u32 raddr_len;
> + struct sockaddr_in laddr;
> + struct sockaddr_in raddr;
> +} __attribute__((aligned(8)));
> +
> struct ckpt_hdr_file_socket {
> struct ckpt_hdr_file common;
> __s32 sock_objref;
> diff --git a/include/net/inet_common.h b/include/net/inet_common.h
> index 18c7732..7ade732 100644
> --- a/include/net/inet_common.h
> +++ b/include/net/inet_common.h
> @@ -45,6 +45,15 @@ extern int inet_ctl_sock_create(struct
> sock **sk,
> unsigned char protocol,
> struct net *net);
>
> +#ifdef CONFIG_CHECKPOINT
> +struct ckpt_ctx;
> +struct ckpt_hdr_socket;
> +extern int inet_checkpoint(struct ckpt_ctx *ctx, struct socket *sock);
> +extern int inet_collect(struct ckpt_ctx *ctx, struct socket *sock);
> +extern int inet_restore(struct ckpt_ctx *cftx, struct socket *sock,
> + struct ckpt_hdr_socket *h);
> +#endif /* CONFIG_CHECKPOINT */
> +
> static inline void inet_ctl_sock_destroy(struct sock *sk)
> {
> sk_release_kernel(sk);
> diff --git a/net/checkpoint.c b/net/checkpoint.c
> index a11ec7a..6960389 100644
> --- a/net/checkpoint.c
> +++ b/net/checkpoint.c
> @@ -711,6 +711,15 @@ struct sock *do_sock_restore(struct ckpt_ctx *ctx)
> if (ret < 0)
> goto err;
>
> + if ((h->sock_common.family == AF_INET) &&
> + (h->sock.state != TCP_LISTEN)) {
> + /* Temporary hack to enable restore of TCP_LISTEN sockets
> + * while forcing anything else to a closed state
> + */
> + sock->sk->sk_state = TCP_CLOSE;
I'll admit by this point I'm a bit confused about the order in which
these things are restored. Does do_sock_restore() run before
inet_restore() below (curious whether its check for TCP_CLOSE will
catch these particular sockets).
> + sock->state = SS_UNCONNECTED;
> + }
> +
> ckpt_hdr_put(ctx, h);
> return sock->sk;
> err:
> diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
> index 80ff87c..c00d8ce 100644
> --- a/net/ipv4/Makefile
> +++ b/net/ipv4/Makefile
> @@ -49,6 +49,7 @@ obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o
> obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o
> obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
> obj-$(CONFIG_NETLABEL) += cipso_ipv4.o
> +obj-$(CONFIG_CHECKPOINT) += checkpoint.o
>
> obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
> xfrm4_output.o
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index 566ea6c..7828885 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -857,6 +857,9 @@ const struct proto_ops inet_stream_ops = {
> .mmap = sock_no_mmap,
> .sendpage = tcp_sendpage,
> .splice_read = tcp_splice_read,
> + .checkpoint = inet_checkpoint,
> + .restore = inet_restore,
> + .collect = inet_collect,
> #ifdef CONFIG_COMPAT
> .compat_setsockopt = compat_sock_common_setsockopt,
> .compat_getsockopt = compat_sock_common_getsockopt,
> @@ -882,6 +885,9 @@ const struct proto_ops inet_dgram_ops = {
> .recvmsg = sock_common_recvmsg,
> .mmap = sock_no_mmap,
> .sendpage = inet_sendpage,
> + .checkpoint = inet_checkpoint,
> + .restore = inet_restore,
> + .collect = inet_collect,
> #ifdef CONFIG_COMPAT
> .compat_setsockopt = compat_sock_common_setsockopt,
> .compat_getsockopt = compat_sock_common_getsockopt,
> diff --git a/net/ipv4/checkpoint.c b/net/ipv4/checkpoint.c
> new file mode 100644
> index 0000000..881e723
> --- /dev/null
> +++ b/net/ipv4/checkpoint.c
> @@ -0,0 +1,204 @@
> +/*
> + * Copyright 2009 IBM Corporation
> + *
> + * Author(s): Dan Smith <[email protected]>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation, version 2 of the
> + * License.
> + */
> +
> +#include <linux/namei.h>
> +#include <linux/checkpoint.h>
> +#include <linux/checkpoint_hdr.h>
> +#include <linux/tcp.h>
> +#include <linux/in.h>
> +#include <linux/deferqueue.h>
> +#include <net/tcp_states.h>
> +#include <net/tcp.h>
> +
> +struct dq_sock {
> + struct ckpt_ctx *ctx;
> + struct sock *sk;
> +};
> +
> +struct dq_buffers {
> + struct ckpt_ctx *ctx;
> + struct sock *sk;
> +};
> +
> +int inet_checkpoint(struct ckpt_ctx *ctx, struct socket *sock)
> +{
> + struct ckpt_hdr_socket_inet *in;
> + int ret = -EINVAL;
> +
> + in = ckpt_hdr_get_type(ctx, sizeof(*in), CKPT_HDR_SOCKET_INET);
> + if (!in)
> + goto out;
Better to just return... I don't think this'll cause a crash (it only
makes ckpt_hdr_put() pass ((struct ckpt_hdr *)NULL)->len to
_ckpt_hdr_put which then ignores it and does a safe kfree(NULL)), but
it won't be safe if the implementation of the ckpt_hdr_*() calls end up
changing.
> +
> + ret = ckpt_sock_getnames(ctx, sock,
> + (struct sockaddr *)&in->laddr, &in->laddr_len,
> + (struct sockaddr *)&in->raddr, &in->raddr_len);
> + if (ret)
> + goto out;
> +
> + ret = ckpt_write_obj(ctx, (struct ckpt_hdr *) in);
> + out:
> + ckpt_hdr_put(ctx, in);
> +
> + return ret;
> +}
> +
> +int inet_collect(struct ckpt_ctx *ctx, struct socket *sock)
> +{
> + return ckpt_obj_collect(ctx, sock->sk, CKPT_OBJ_SOCK);
> +}
> +
> +static int inet_read_buffer(struct ckpt_ctx *ctx, struct sk_buff_head *queue)
> +{
> + struct ckpt_hdr_socket_buffer *h;
> + int len;
> + int ret;
> + struct sk_buff *skb;
> +
> + h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_SOCKET_BUFFER);
> + if (IS_ERR(h))
> + return PTR_ERR(h);
> +
> + len = _ckpt_read_obj_type(ctx, NULL, 0, CKPT_HDR_BUFFER);
> + if (len < 0) {
> + ret = len;
> + goto out;
> + } else if (len > SKB_MAX_ALLOC) {
> + ckpt_debug("Socket buffer too big (%i > %lu)",
> + len, SKB_MAX_ALLOC);
> + ret = -ENOSPC;
> + goto out;
> + }
> +
> + skb = alloc_skb(len, GFP_KERNEL);
> + if (!skb) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + ret = ckpt_kread(ctx, skb_put(skb, len), len);
> + if (ret < 0)
> + goto out;
> +
> + spin_lock(&queue->lock);
> + skb_queue_tail(queue, skb);
> + spin_unlock(&queue->lock);
> + out:
> + ckpt_hdr_put(ctx, h);
> +
> + if (ret < 0)
> + kfree_skb(skb);
> +
> + return ret;
> +}
> +
> +static int inet_read_buffers(struct ckpt_ctx *ctx, struct sk_buff_head
> *queue)
> +{
> + struct ckpt_hdr_socket_queue *h;
> + int ret = 0;
> + int i;
> +
> + h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_SOCKET_QUEUE);
> + if (IS_ERR(h))
> + return PTR_ERR(h);
> +
> + for (i = 0; i < h->skb_count; i++) {
> + ret = inet_read_buffer(ctx, queue);
> + ckpt_debug("read inet buffer %i: %i", i, ret);
> + if (ret < 0)
> + goto out;
> +
> + if (ret > h->total_bytes) {
> + ckpt_debug("Buffers exceeded claim");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + h->total_bytes -= ret;
> + ret = 0;
> + }
> +
> + ret = h->skb_count;
> + out:
> + ckpt_hdr_put(ctx, h);
> +
> + return ret;
> +}
> +
> +static int inet_deferred_restore_buffers(void *data)
> +{
> + struct dq_buffers *dq = (struct dq_buffers *)data;
> + struct ckpt_ctx *ctx = dq->ctx;
> + struct sock *sk = dq->sk;
> + int ret;
> +
> + ret = inet_read_buffers(ctx, &sk->sk_receive_queue);
> + ckpt_debug("(R) inet_read_buffers: %i\n", ret);
> + if (ret < 0)
> + return ret;
> +
> + ret = inet_read_buffers(ctx, &sk->sk_write_queue);
> + ckpt_debug("(W) inet_read_buffers: %i\n", ret);
> +
> + return ret;
> +}
> +
> +static int inet_defer_restore_buffers(struct ckpt_ctx *ctx, struct sock *sk)
> +{
> + struct dq_buffers dq;
> +
> + dq.ctx = ctx;
> + dq.sk = sk;
> +
> + return deferqueue_add(ctx->files_deferq, &dq, sizeof(dq),
> + inet_deferred_restore_buffers, NULL);
> +}
> +
> +int inet_restore(struct ckpt_ctx *ctx,
> + struct socket *sock,
> + struct ckpt_hdr_socket *h)
> +{
> + struct ckpt_hdr_socket_inet *in;
> + int ret = 0;
> +
> + in = ckpt_read_obj_type(ctx, sizeof(*in), CKPT_HDR_SOCKET_INET);
> + if (IS_ERR(in))
> + return PTR_ERR(in);
> +
> + /* Listening sockets and those that are closed but have a local
> + * address need to call bind()
> + */
> + if ((h->sock.state == TCP_LISTEN) ||
> + ((h->sock.state == TCP_CLOSE) && (in->laddr_len > 0))) {
> + sock->sk->sk_reuse = 2;
> + inet_sk(sock->sk)->freebind = 1;
> + ret = sock->ops->bind(sock,
> + (struct sockaddr *)&in->laddr,
> + in->laddr_len);
> + ckpt_debug("inet bind: %i\n", ret);
> + if (ret < 0)
> + goto out;
> +
> + if (h->sock.state == TCP_LISTEN) {
> + ret = sock->ops->listen(sock, h->sock.backlog);
> + ckpt_debug("inet listen: %i\n", ret);
> + if (ret < 0)
> + goto out;
> + }
> + } else {
> + if (!sock_flag(sock->sk, SOCK_DEAD))
> + ret = inet_defer_restore_buffers(ctx, sock->sk);
> + }
> + out:
> + ckpt_hdr_put(ctx, in);
> +
> + return ret;
> + }
> +
> --
> 1.6.2.5
>
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