7b92493ab1
The SMR-protected inpcb lookup algorithm currently has to check whether
a matching inpcb belongs to a jail, in order to prioritize jailed
bound sockets. To do this it has to maintain a ucred reference, and for
this to be safe, the reference can't be released until the UMA
destructor is called, and this will not happen within any bounded time
period.
Changing SMR to periodically recycle garbage is not trivial. Instead,
let's implement SMR-synchronized lookup without needing to dereference
inp_cred. This will allow the inpcb code to free the inp_cred reference
immediately when a PCB is freed, ensuring that ucred (and thus jail)
references are released promptly.
Commit 220d892129 ("inpcb: immediately return matching pcb on lookup")
gets us part of the way there. This patch goes further to handle
lookups of unconnected sockets. Here, the strategy is to maintain a
well-defined order of items within a hash chain so that a wild lookup
can simply return the first match and preserve existing semantics. This
makes insertion of listening sockets more complicated in order to make
lookup simpler, which seems like the right tradeoff anyway given that
bind() is already a fairly expensive operation and lookups are more
common.
In particular, when inserting an unconnected socket, in_pcbinhash() now
keeps the following ordering:
- jailed sockets before non-jailed sockets,
- specified local addresses before unspecified local addresses.
Most of the change adds a separate SMR-based lookup path for inpcb hash
lookups. When a match is found, we try to lock the inpcb and
re-validate its connection info. In the common case, this works well
and we can simply return the inpcb. If this fails, typically because
something is concurrently modifying the inpcb, we go to the slow path,
which performs a serialized lookup.
Note, I did not touch lbgroup lookup, since there the credential
reference is formally synchronized by net_epoch, not SMR. In
particular, lbgroups are rarely allocated or freed.
I think it is possible to simplify in_pcblookup_hash_wild_locked() now,
but I didn't do it in this patch.
Discussed with: glebius
Tested by: glebius
Sponsored by: Klara, Inc.
Sponsored by: Modirum MDPay
Differential Revision: https://reviews.freebsd.org/D38572
116 lines
5.2 KiB
C
116 lines
5.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $KAME: in6_pcb.h,v 1.13 2001/02/06 09:16:53 itojun Exp $
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*/
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/*-
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* Copyright (c) 1982, 1986, 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)in_pcb.h 8.1 (Berkeley) 6/10/93
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* $FreeBSD$
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*/
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#ifndef _NETINET6_IN6_PCB_H_
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#define _NETINET6_IN6_PCB_H_
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#ifdef _KERNEL
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#define satosin6(sa) ((struct sockaddr_in6 *)(sa))
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#define sin6tosa(sin6) ((struct sockaddr *)(sin6))
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#define ifatoia6(ifa) ((struct in6_ifaddr *)(ifa))
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void in6_pcbpurgeif0(struct inpcbinfo *, struct ifnet *);
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void in6_losing(struct inpcb *);
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int in6_pcbbind(struct inpcb *, struct sockaddr_in6 *, struct ucred *);
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int in6_pcbconnect(struct inpcb *, struct sockaddr_in6 *, struct ucred *,
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bool);
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void in6_pcbdisconnect(struct inpcb *);
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struct inpcb *
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in6_pcblookup_local(struct inpcbinfo *,
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struct in6_addr *, u_short, int,
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struct ucred *);
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struct inpcb *
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in6_pcblookup_hash_locked(struct inpcbinfo *pcbinfo,
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const struct in6_addr *faddr, u_int fport_arg,
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const struct in6_addr *laddr, u_int lport_arg,
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int lookupflags, uint8_t);
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struct inpcb *
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in6_pcblookup(struct inpcbinfo *, struct in6_addr *,
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u_int, struct in6_addr *, u_int, int,
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struct ifnet *);
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struct inpcb *
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in6_pcblookup_mbuf(struct inpcbinfo *, struct in6_addr *,
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u_int, struct in6_addr *, u_int, int,
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struct ifnet *ifp, struct mbuf *);
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void in6_pcbnotify(struct inpcbinfo *, struct sockaddr_in6 *, u_int,
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const struct sockaddr_in6 *, u_int, int, void *,
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struct inpcb *(*)(struct inpcb *, int));
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struct inpcb *
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in6_rtchange(struct inpcb *, int);
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struct sockaddr *
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in6_sockaddr(in_port_t port, struct in6_addr *addr_p);
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struct sockaddr *
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in6_v4mapsin6_sockaddr(in_port_t port, struct in_addr *addr_p);
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int in6_getpeeraddr(struct socket *so, struct sockaddr **nam);
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int in6_getsockaddr(struct socket *so, struct sockaddr **nam);
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int in6_mapped_sockaddr(struct socket *so, struct sockaddr **nam);
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int in6_mapped_peeraddr(struct socket *so, struct sockaddr **nam);
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int in6_selecthlim(struct inpcb *, struct ifnet *);
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int in6_pcbsetport(struct in6_addr *, struct inpcb *, struct ucred *);
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void init_sin6(struct sockaddr_in6 *sin6, struct mbuf *m, int);
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#endif /* _KERNEL */
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#endif /* !_NETINET6_IN6_PCB_H_ */
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