unimore/kernel-hacking-2024-linux-steffo
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udp: add encap_destroy callback

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Users of udp encapsulation currently have an encap_rcv callback which they can
use to hook into the udp receive path.

In situations where a encapsulation user allocates resources associated with a
udp encap socket, it may be convenient to be able to also hook the proto
.destroy operation.  For example, if an encap user holds a reference to the
udp socket, the destroy hook might be used to relinquish this reference.

This patch adds a socket destroy hook into udp, which is set and enabled
in the same way as the existing encap_rcv hook.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Parkin 2013-03-19 06:11:12 +00:00 committed by David S. Miller
parent f1e79e2080
commit 44046a593e
3 changed files with 16 additions and 0 deletions
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1
include/linux/udp.h
View file

@ -68,6 +68,7 @@ struct udp_sock {
* For encapsulation sockets.
*/
int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
void (*encap_destroy)(struct sock *sk);
};
static inline struct udp_sock *udp_sk(const struct sock *sk)

7
net/ipv4/udp.c
View file

@ -1762,9 +1762,16 @@ int udp_rcv(struct sk_buff *skb)
void udp_destroy_sock(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
bool slow = lock_sock_fast(sk);
udp_flush_pending_frames(sk);
unlock_sock_fast(sk, slow);
if (static_key_false(&udp_encap_needed) && up->encap_type) {
void (*encap_destroy)(struct sock *sk);
encap_destroy = ACCESS_ONCE(up->encap_destroy);
if (encap_destroy)
encap_destroy(sk);
}
}
/*

8
net/ipv6/udp.c
View file

@ -1285,10 +1285,18 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
void udpv6_destroy_sock(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
lock_sock(sk);
udp_v6_flush_pending_frames(sk);
release_sock(sk);
if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
void (*encap_destroy)(struct sock *sk);
encap_destroy = ACCESS_ONCE(up->encap_destroy);
if (encap_destroy)
encap_destroy(sk);
}
inet6_destroy_sock(sk);
}