[Devel] [PATCH] Restore gso_type fields on sockets and buffers

[Dan Smith]

The sk_gso_type field gets set during TCP connect(), so we need to set that
properly when we synthesize the connection post-restart.  Also, restore
the gso_type field on socket buffers so that they're properly handled on
the incoming path.  Instead of storing that per-buffer, use the value
that should have been set on it from the socket in the first place,
to avoid needing to make sure the user doesn't try to restore a UDP
buffer into a TCP socket (for example).

Signed-off-by: Dan Smith <danms at us.ibm.com>
---
 include/linux/checkpoint.h |    2 +-
 net/checkpoint.c           |   10 +++++++---
 net/ipv4/checkpoint.c      |   32 +++++++++++++++++++++++---------
 3 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index d4765f6..1c57abc 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -102,7 +102,7 @@ extern int ckpt_sock_getnames(struct ckpt_ctx *ctx,
 			      struct socket *socket,
 			      struct sockaddr *loc, unsigned *loc_len,
 			      struct sockaddr *rem, unsigned *rem_len);
-struct sk_buff *sock_restore_skb(struct ckpt_ctx *ctx);
+struct sk_buff *sock_restore_skb(struct ckpt_ctx *ctx, struct sock *sk);
 void sock_listening_list_free(struct list_head *head);
 
 /* ckpt kflags */
diff --git a/net/checkpoint.c b/net/checkpoint.c
index 32ccaba..cff3211 100644
--- a/net/checkpoint.c
+++ b/net/checkpoint.c
@@ -115,7 +115,8 @@ static void sock_record_header_info(struct sk_buff *skb,
 }
 
 int sock_restore_header_info(struct sk_buff *skb,
-			     struct ckpt_hdr_socket_buffer *h)
+			     struct ckpt_hdr_socket_buffer *h,
+			     struct sock *sk)
 {
 	if (h->mac_header + h->mac_len != h->network_header) {
 		ckpt_debug("skb mac_header %llu+%llu != network header %llu\n",
@@ -158,6 +159,8 @@ int sock_restore_header_info(struct sk_buff *skb,
 	skb->data = skb->head + skb->hdr_len;
 	skb->len = h->skb_len;
 
+	skb_shinfo(skb)->gso_type = sk->sk_gso_type;
+
 	return 0;
 }
 
@@ -199,7 +202,8 @@ static int sock_restore_skb_frag(struct ckpt_ctx *ctx,
 	return ret < 0 ? ret : fraglen;
 }
 
-struct sk_buff *sock_restore_skb(struct ckpt_ctx *ctx)
+struct sk_buff *sock_restore_skb(struct ckpt_ctx *ctx,
+				 struct sock *sk)
 {
 	struct ckpt_hdr_socket_buffer *h;
 	struct sk_buff *skb = NULL;
@@ -251,7 +255,7 @@ struct sk_buff *sock_restore_skb(struct ckpt_ctx *ctx)
 		goto out;
 	}
 
-	sock_restore_header_info(skb, h);
+	sock_restore_header_info(skb, h, sk);
 
  out:
 	ckpt_hdr_put(ctx, h);
diff --git a/net/ipv4/checkpoint.c b/net/ipv4/checkpoint.c
index ee41633..92a92b0 100644
--- a/net/ipv4/checkpoint.c
+++ b/net/ipv4/checkpoint.c
@@ -184,9 +184,12 @@ static int sock_inet_tcp_cptrst(struct ckpt_ctx *ctx,
 	return 0;
 }
 
-static int sock_inet_restore_addrs(struct inet_sock *inet,
-				   struct ckpt_hdr_socket_inet *hh)
+static int sock_inet_restore_connection(struct sock *sk,
+					struct ckpt_hdr_socket_inet *hh)
 {
+	struct inet_sock *inet = inet_sk(sk);
+	int tcp_gso = sk->sk_family == AF_INET ? SKB_GSO_TCPV4 : SKB_GSO_TCPV6;
+
 	inet->daddr = hh->raddr.sin_addr.s_addr;
 	inet->saddr = hh->laddr.sin_addr.s_addr;
 	inet->rcv_saddr = inet->saddr;
@@ -194,6 +197,15 @@ static int sock_inet_restore_addrs(struct inet_sock *inet,
 	inet->dport = hh->raddr.sin_port;
 	inet->sport = hh->laddr.sin_port;
 
+	if (sk->sk_protocol == IPPROTO_TCP)
+		sk->sk_gso_type = tcp_gso;
+	else if (sk->sk_protocol == IPPROTO_UDP)
+		sk->sk_gso_type = SKB_GSO_UDP;
+	else {
+		ckpt_debug("Unsupported socket type while setting GSO\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -213,7 +225,7 @@ static int sock_inet_cptrst(struct ckpt_ctx *ctx,
 		CKPT_COPY(op, hh->saddr, inet->saddr);
 		CKPT_COPY(op, hh->sport, inet->sport);
 	} else {
-		ret = sock_inet_restore_addrs(inet, hh);
+		ret = sock_inet_restore_connection(sk, hh);
 		if (ret)
 			return ret;
 	}
@@ -291,11 +303,12 @@ int inet_collect(struct ckpt_ctx *ctx, struct socket *sock)
 }
 
 static int inet_read_buffer(struct ckpt_ctx *ctx,
-			    struct sk_buff_head *queue)
+			    struct sk_buff_head *queue,
+			    struct sock *sk)
 {
 	struct sk_buff *skb = NULL;
 
-	skb = sock_restore_skb(ctx);
+	skb = sock_restore_skb(ctx, sk);
 	if (IS_ERR(skb))
 		return PTR_ERR(skb);
 
@@ -305,7 +318,8 @@ static int inet_read_buffer(struct ckpt_ctx *ctx,
 }
 
 static int inet_read_buffers(struct ckpt_ctx *ctx,
-			     struct sk_buff_head *queue)
+			     struct sk_buff_head *queue,
+			     struct sock *sk)
 {
 	struct ckpt_hdr_socket_queue *h;
 	int ret = 0;
@@ -316,7 +330,7 @@ static int inet_read_buffers(struct ckpt_ctx *ctx,
 		return PTR_ERR(h);
 
 	for (i = 0; i < h->skb_count; i++) {
-		ret = inet_read_buffer(ctx, queue);
+		ret = inet_read_buffer(ctx, queue, sk);
 		ckpt_debug("read inet buffer %i: %i", i, ret);
 		if (ret < 0)
 			goto out;
@@ -344,12 +358,12 @@ static int inet_deferred_restore_buffers(void *data)
 	struct sock *sk = dq->sk;
 	int ret;
 
-	ret = inet_read_buffers(ctx, &sk->sk_receive_queue);
+	ret = inet_read_buffers(ctx, &sk->sk_receive_queue, sk);
 	ckpt_debug("(R) inet_read_buffers: %i\n", ret);
 	if (ret < 0)
 		return ret;
 
-	ret = inet_read_buffers(ctx, &sk->sk_write_queue);
+	ret = inet_read_buffers(ctx, &sk->sk_write_queue, sk);
 	ckpt_debug("(W) inet_read_buffers: %i\n", ret);
 
 	return ret;
-- 
1.6.2.5

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