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net-tcp: fastopen: fix high order allocations

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This patch fixes two bugs in fastopen :

1) The tcp_sendmsg(...,  @size) argument was ignored.

   Code was relying on user not fooling the kernel with iovec mismatches

2) When MTU is about 64KB, tcp_send_syn_data() attempts order-5
allocations, which are likely to fail when memory gets fragmented.

Fixes: 783237e8daf13 ("net-tcp: Fast Open client - sending SYN-data")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Tested-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2014-02-20 10:09:18 -08:00 committed by David S. Miller
parent 68ad785c00
commit f5ddcbbb40
3 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/tcp.h
View File

@ -1303,7 +1303,8 @@ struct tcp_fastopen_request {
/* Fast Open cookie. Size 0 means a cookie request */ /* Fast Open cookie. Size 0 means a cookie request */
struct tcp_fastopen_cookie cookie; struct tcp_fastopen_cookie cookie;
struct msghdr *data; /* data in MSG_FASTOPEN */ struct msghdr *data; /* data in MSG_FASTOPEN */
u16 copied; /* queued in tcp_connect() */ size_t size;
int copied; /* queued in tcp_connect() */
}; };
void tcp_free_fastopen_req(struct tcp_sock *tp); void tcp_free_fastopen_req(struct tcp_sock *tp);

8
net/ipv4/tcp.c
View File

@ -1044,7 +1044,8 @@ void tcp_free_fastopen_req(struct tcp_sock *tp)
} }
} }
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *size) static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
int *copied, size_t size)
{ {
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
int err, flags; int err, flags;
@ -1059,11 +1060,12 @@ static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *size)
if (unlikely(tp->fastopen_req == NULL)) if (unlikely(tp->fastopen_req == NULL))
return -ENOBUFS; return -ENOBUFS;
tp->fastopen_req->data = msg; tp->fastopen_req->data = msg;
tp->fastopen_req->size = size;
flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0; flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
err = __inet_stream_connect(sk->sk_socket, msg->msg_name, err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
msg->msg_namelen, flags); msg->msg_namelen, flags);
*size = tp->fastopen_req->copied; *copied = tp->fastopen_req->copied;
tcp_free_fastopen_req(tp); tcp_free_fastopen_req(tp);
return err; return err;
} }
@ -1083,7 +1085,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
flags = msg->msg_flags; flags = msg->msg_flags;
if (flags & MSG_FASTOPEN) { if (flags & MSG_FASTOPEN) {
err = tcp_sendmsg_fastopen(sk, msg, &copied_syn); err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
if (err == -EINPROGRESS && copied_syn > 0) if (err == -EINPROGRESS && copied_syn > 0)
goto out; goto out;
else if (err) else if (err)

7
net/ipv4/tcp_output.c
View File

@ -2908,7 +2908,12 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
space = __tcp_mtu_to_mss(sk, inet_csk(sk)->icsk_pmtu_cookie) - space = __tcp_mtu_to_mss(sk, inet_csk(sk)->icsk_pmtu_cookie) -
MAX_TCP_OPTION_SPACE; MAX_TCP_OPTION_SPACE;
syn_data = skb_copy_expand(syn, skb_headroom(syn), space, space = min_t(size_t, space, fo->size);
/* limit to order-0 allocations */
space = min_t(size_t, space, SKB_MAX_HEAD(MAX_TCP_HEADER));
syn_data = skb_copy_expand(syn, MAX_TCP_HEADER, space,
sk->sk_allocation); sk->sk_allocation);
if (syn_data == NULL) if (syn_data == NULL)
goto fallback; goto fallback;