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tcp, ulp: Add clone operation to tcp_ulp_ops

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If ULP is used on a listening socket, icsk_ulp_ops and icsk_ulp_data are
copied when the listener is cloned. Sometimes the clone is immediately
deleted, which will invoke the release op on the clone and likely
corrupt the listening socket's icsk_ulp_data.

The clone operation is invoked immediately after the clone is copied and
gives the ULP type an opportunity to set up the clone socket and its
icsk_ulp_data.

The MPTCP ULP clone will silently fallback to plain TCP on allocation
failure, so 'clone()' does not need to return an error code.

v6 -> v7:
 - move and rename ulp clone helper to make it inline-friendly
v5 -> v6:
 - clarified MPTCP clone usage in commit message

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mat Martineau 2020-01-09 07:59:18 -08:00 committed by David S. Miller
parent c74a39c861
commit 1323059301
2 changed files with 17 additions and 0 deletions
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3
include/net/tcp.h
View File

@ -2154,6 +2154,9 @@ struct tcp_ulp_ops {
/* diagnostic */
int (*get_info)(const struct sock *sk, struct sk_buff *skb);
size_t (*get_info_size)(const struct sock *sk);
/* clone ulp */
void (*clone)(const struct request_sock *req, struct sock *newsk,
const gfp_t priority);
char name[TCP_ULP_NAME_MAX];
struct module *owner;

14
net/ipv4/inet_connection_sock.c
View File

@ -770,6 +770,18 @@ void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
}
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
const gfp_t priority)
{
struct inet_connection_sock *icsk = inet_csk(newsk);
if (!icsk->icsk_ulp_ops)
return;
if (icsk->icsk_ulp_ops->clone)
icsk->icsk_ulp_ops->clone(req, newsk, priority);
}
/**
* inet_csk_clone_lock - clone an inet socket, and lock its clone
* @sk: the socket to clone
@ -810,6 +822,8 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
/* Deinitialize accept_queue to trap illegal accesses. */
memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
inet_clone_ulp(req, newsk, priority);
security_inet_csk_clone(newsk, req);
}
return newsk;