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From:
Alexander Bluhm <bluhm@openbsd.org>
Subject:
Re: ip sysctl atomic
To:
Mark Kettenis <mark.kettenis@xs4all.nl>
Cc:
tech@openbsd.org, claudio@openbsd.org
Date:
Thu, 16 May 2024 21:42:01 +0200

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  • Mark Kettenis:

    ip sysctl atomic

  • On Thu, May 16, 2024 at 02:52:29PM +0200, Mark Kettenis wrote:
    > > You write it once into common memory and you read it
    > > once.  Thinking every time about the context whether it is safe or
    > > not to rely on the compiler is too difficult for me.
    > 
    > I feel your pain. The compilers make it pretty much impossible to
    > reason about these things.  But we can't wrap *every* global variables
    > access in the kernel in READ_ONCE() or WRITE_ONCE.  The code will
    > become unreadable.
    
    When making code MP safe it feels better to mark every access
    explicitly.  But in the long run too many macros may be confusing.
    
    > I wonder if you should just declare all those global variables that
    > you access with READ_ONCE() should be just declared volatile.
    
    I can live with this solution, diff is below:
    - Mark integer in sysctl_int_bounded volatile.
    - Declare globals volatile.
    - Use consistent ip_ prefix for global variables.
    - Add some locking comments.
    - in IP input, forward, output use flags for consistent view
    
    ok?
    
    bluhm
    
    Index: kern/kern_sysctl.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/kern/kern_sysctl.c,v
    diff -u -p -r1.427 kern_sysctl.c
    --- kern/kern_sysctl.c	12 Apr 2024 16:07:09 -0000	1.427
    +++ kern/kern_sysctl.c	16 May 2024 19:22:05 -0000
    @@ -1003,21 +1003,36 @@ sysctl_securelevel_int(void *oldp, size_
      */
     int
     sysctl_int_bounded(void *oldp, size_t *oldlenp, void *newp, size_t newlen,
    -    int *valp, int minimum, int maximum)
    +    volatile int *valp, int minimum, int maximum)
     {
    -	int val = *valp;
    +	int oldval, newval;
     	int error;
     
     	/* read only */
    -	if (newp == NULL || minimum > maximum)
    -		return (sysctl_rdint(oldp, oldlenp, newp, val));
    +	if (newp != NULL && minimum > maximum)
    +		return (EPERM);
     
    -	if ((error = sysctl_int(oldp, oldlenp, newp, newlen, &val)))
    -		return (error);
    -	/* outside limits */
    -	if (val < minimum || maximum < val)
    +	if (oldp && *oldlenp < sizeof(int))
    +		return (ENOMEM);
    +	if (newp && newlen != sizeof(int))
     		return (EINVAL);
    -	*valp = val;
    +	*oldlenp = sizeof(int);
    +
    +	/* copyin() may sleep, call it first */
    +	if (newp) {
    +		if ((error = copyin(newp, &newval, sizeof(int))))
    +			return (error);
    +		/* outside limits */
    +		if (newval < minimum || maximum < newval)
    +			return (EINVAL);
    +	}
    +	if (oldp) {
    +		oldval = *valp;
    +		if ((error = copyout(&oldval, oldp, sizeof(int))))
    +			return (error);
    +	}
    +	if (newp)
    +		*valp = newval;
     	return (0);
     }
     
    Index: net/pf.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/net/pf.c,v
    diff -u -p -r1.1196 pf.c
    --- net/pf.c	14 May 2024 08:26:13 -0000	1.1196
    +++ net/pf.c	16 May 2024 19:22:05 -0000
    @@ -7958,12 +7958,17 @@ done:
     		switch (pd.naf) {
     		case AF_INET:
     			if (pd.dir == PF_IN) {
    -				if (ipforwarding == 0) {
    +				int flags;
    +
    +				if (ip_forwarding == 0) {
     					ipstat_inc(ips_cantforward);
     					action = PF_DROP;
     					break;
     				}
    -				ip_forward(pd.m, ifp, NULL, 1);
    +				flags = IP_FORWARDING | IP_REDIRECT;
    +				if (ip_directedbcast)
    +					SET(flags, IP_ALLOWBROADCAST);
    +				ip_forward(pd.m, ifp, NULL, flags);
     			} else
     				ip_output(pd.m, NULL, NULL, 0, NULL, NULL, 0);
     			break;
    Index: netinet/if_ether.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/if_ether.c,v
    diff -u -p -r1.267 if_ether.c
    --- netinet/if_ether.c	18 Dec 2023 13:30:44 -0000	1.267
    +++ netinet/if_ether.c	16 May 2024 19:22:05 -0000
    @@ -69,6 +69,7 @@
      *  Locks used to protect struct members in this file:
      *	a	atomic operations
      *	I	immutable after creation
    + *	u	unlocked integer access
      *	K	kernel lock
      *	m	arp mutex, needed when net lock is shared
      *	N	net lock
    @@ -86,8 +87,8 @@ struct llinfo_arp {
     
     /* timer values */
     int 	arpt_prune = (5 * 60);	/* [I] walk list every 5 minutes */
    -int 	arpt_keep = (20 * 60);	/* [a] once resolved, cache for 20 minutes */
    -int 	arpt_down = 20;	/* [a] once declared down, don't send for 20 secs */
    +volatile int arpt_keep = (20 * 60); /* [u] once resolved, cache 20 minutes */
    +volatile int arpt_down = 20;	/* [u] once declared down, don't send 20 secs */
     
     struct mbuf *arppullup(struct mbuf *m);
     void arpinvalidate(struct rtentry *);
    Index: netinet/if_ether.h
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/if_ether.h,v
    diff -u -p -r1.92 if_ether.h
    --- netinet/if_ether.h	14 Feb 2024 22:41:48 -0000	1.92
    +++ netinet/if_ether.h	16 May 2024 19:22:05 -0000
    @@ -245,8 +245,8 @@ struct	arpcom {
     	const struct ether_brport *ac_brport;
     };
     
    -extern int arpt_keep;				/* arp resolved cache expire */
    -extern int arpt_down;				/* arp down cache expire */
    +extern volatile int arpt_keep;		/* arp resolved cache expire */
    +extern volatile int arpt_down;		/* arp down cache expire */
     
     extern u_int8_t etherbroadcastaddr[ETHER_ADDR_LEN];
     extern u_int8_t etheranyaddr[ETHER_ADDR_LEN];
    Index: netinet/in_pcb.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/in_pcb.c,v
    diff -u -p -r1.302 in_pcb.c
    --- netinet/in_pcb.c	19 Apr 2024 10:13:58 -0000	1.302
    +++ netinet/in_pcb.c	16 May 2024 19:22:05 -0000
    @@ -105,13 +105,18 @@ const struct in_addr zeroin_addr;
     const union inpaddru zeroin46_addr;
     
     /*
    + * Locks used to protect global variables in this file:
    + *	u	unlocked integer access
    + */
    +
    +/*
      * These configure the range of local port addresses assigned to
      * "unspecified" outgoing connections/packets/whatever.
      */
    -int ipport_firstauto = IPPORT_RESERVED;
    -int ipport_lastauto = IPPORT_USERRESERVED;
    -int ipport_hifirstauto = IPPORT_HIFIRSTAUTO;
    -int ipport_hilastauto = IPPORT_HILASTAUTO;
    +volatile int ipport_firstauto = IPPORT_RESERVED;	/* [u] */
    +volatile int ipport_lastauto = IPPORT_USERRESERVED;	/* [u] */
    +volatile int ipport_hifirstauto = IPPORT_HIFIRSTAUTO;	/* [u] */
    +volatile int ipport_hilastauto = IPPORT_HILASTAUTO;	/* [u] */
     
     struct baddynamicports baddynamicports;
     struct baddynamicports rootonlyports;
    Index: netinet/ip_icmp.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_icmp.c,v
    diff -u -p -r1.192 ip_icmp.c
    --- netinet/ip_icmp.c	16 Sep 2023 09:33:27 -0000	1.192
    +++ netinet/ip_icmp.c	16 May 2024 19:22:05 -0000
    @@ -589,7 +589,7 @@ reflect:
     		struct sockaddr_in ssrc;
     		struct rtentry *newrt = NULL;
     
    -		if (icmp_rediraccept == 0 || ipforwarding == 1)
    +		if (icmp_rediraccept == 0 || ip_forwarding == 1)
     			goto freeit;
     		if (code > 3)
     			goto badcode;
    Index: netinet/ip_input.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_input.c,v
    diff -u -p -r1.394 ip_input.c
    --- netinet/ip_input.c	8 May 2024 13:01:30 -0000	1.394
    +++ netinet/ip_input.c	16 May 2024 19:22:05 -0000
    @@ -83,33 +83,41 @@
     #include <netinet/ip_carp.h>
     #endif
     
    +/*
    + * Locks used to protect global variables in this file:
    + *	I	immutable after creation
    + *	a	atomic operations
    + *	u	unlocked integer access
    + *	N	net lock
    + *	F	fragment reassembly ipq_mutex
    + */
    +
     /* values controllable via sysctl */
    -int	ipforwarding = 0;
    -int	ipmforwarding = 0;
    -int	ipmultipath = 0;
    -int	ipsendredirects = 1;
    +volatile int	ip_forwarding = 0;		/* [u] */
    +volatile int	ip_mforwarding = 0;		/* [u] */
    +int	ipmultipath = 0;			/* [N] */
    +volatile int	ip_sendredirects = 1;		/* [u] */
     int	ip_dosourceroute = 0;
    -int	ip_defttl = IPDEFTTL;
    +volatile int	ip_defttl = IPDEFTTL;		/* [u] */
     int	ip_mtudisc = 1;
     int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
    -int	ip_directedbcast = 0;
    +volatile int	ip_directedbcast = 0;		/* [u] */
     
     /* Protects `ipq' and `ip_frags'. */
     struct mutex	ipq_mutex = MUTEX_INITIALIZER(IPL_SOFTNET);
     
    -/* IP reassembly queue */
    -LIST_HEAD(, ipq) ipq;
    +LIST_HEAD(, ipq) ipq;			/* [F] reassembly queue */
     
     /* Keep track of memory used for reassembly */
    -int	ip_maxqueue = 300;
    -int	ip_frags = 0;
    +volatile int	ip_maxqueue = 300;	/* [u] maximum fragments in queue */
    +int		ip_frags;		/* [F] number of fragments */
     
     const struct sysctl_bounded_args ipctl_vars[] = {
     #ifdef MROUTING
     	{ IPCTL_MRTPROTO, &ip_mrtproto, SYSCTL_INT_READONLY },
     #endif
    -	{ IPCTL_FORWARDING, &ipforwarding, 0, 2 },
    -	{ IPCTL_SENDREDIRECTS, &ipsendredirects, 0, 1 },
    +	{ IPCTL_FORWARDING, &ip_forwarding, 0, 2 },
    +	{ IPCTL_SENDREDIRECTS, &ip_sendredirects, 0, 1 },
     	{ IPCTL_DEFTTL, &ip_defttl, 0, 255 },
     	{ IPCTL_DIRECTEDBCAST, &ip_directedbcast, 0, 1 },
     	{ IPCTL_IPPORT_FIRSTAUTO, &ipport_firstauto, 0, 65535 },
    @@ -117,7 +125,7 @@ const struct sysctl_bounded_args ipctl_v
     	{ IPCTL_IPPORT_HIFIRSTAUTO, &ipport_hifirstauto, 0, 65535 },
     	{ IPCTL_IPPORT_HILASTAUTO, &ipport_hilastauto, 0, 65535 },
     	{ IPCTL_IPPORT_MAXQUEUE, &ip_maxqueue, 0, 10000 },
    -	{ IPCTL_MFORWARDING, &ipmforwarding, 0, 1 },
    +	{ IPCTL_MFORWARDING, &ip_mforwarding, 0, 1 },
     	{ IPCTL_ARPTIMEOUT, &arpt_keep, 0, INT_MAX },
     	{ IPCTL_ARPDOWN, &arpt_down, 0, INT_MAX },
     };
    @@ -137,8 +145,8 @@ static struct mbuf_queue	ipsendraw_mq;
     extern struct niqueue		arpinq;
     
     int	ip_ours(struct mbuf **, int *, int, int);
    -int	ip_dooptions(struct mbuf *, struct ifnet *);
    -int	in_ouraddr(struct mbuf *, struct ifnet *, struct route *);
    +int	ip_dooptions(struct mbuf *, struct ifnet *, int);
    +int	in_ouraddr(struct mbuf *, struct ifnet *, struct route *, int);
     
     int		ip_fragcheck(struct mbuf **, int *);
     struct mbuf *	ip_reass(struct ipqent *, struct ipq *);
    @@ -431,7 +439,7 @@ ip_input_if(struct mbuf **mp, int *offp,
     #if NPF > 0
     	struct in_addr odst;
     #endif
    -	int pfrdr = 0;
    +	int flags = 0;
     
     	KASSERT(*offp == 0);
     
    @@ -461,9 +469,15 @@ ip_input_if(struct mbuf **mp, int *offp,
     		goto bad;
     
     	ip = mtod(m, struct ip *);
    -	pfrdr = odst.s_addr != ip->ip_dst.s_addr;
    +	if (odst.s_addr != ip->ip_dst.s_addr)
    +		SET(flags, IP_REDIRECT);
     #endif
     
    +	if (ip_forwarding != 0)
    +		SET(flags, IP_FORWARDING);
    +	if (ip_directedbcast)
    +		SET(flags, IP_ALLOWBROADCAST);
    +
     	hlen = ip->ip_hl << 2;
     
     	/*
    @@ -472,7 +486,7 @@ ip_input_if(struct mbuf **mp, int *offp,
     	 * error was detected (causing an icmp message
     	 * to be sent and the original packet to be freed).
     	 */
    -	if (hlen > sizeof (struct ip) && ip_dooptions(m, ifp)) {
    +	if (hlen > sizeof (struct ip) && ip_dooptions(m, ifp, flags)) {
     		m = *mp = NULL;
     		goto bad;
     	}
    @@ -483,7 +497,7 @@ ip_input_if(struct mbuf **mp, int *offp,
     		goto out;
     	}
     
    -	switch(in_ouraddr(m, ifp, &ro)) {
    +	switch(in_ouraddr(m, ifp, &ro, flags)) {
     	case 2:
     		goto bad;
     	case 1:
    @@ -500,7 +514,7 @@ ip_input_if(struct mbuf **mp, int *offp,
     		m->m_flags |= M_MCAST;
     
     #ifdef MROUTING
    -		if (ipmforwarding && ip_mrouter[ifp->if_rdomain]) {
    +		if (ip_mforwarding && ip_mrouter[ifp->if_rdomain]) {
     			int error;
     
     			if (m->m_flags & M_EXT) {
    @@ -565,7 +579,7 @@ ip_input_if(struct mbuf **mp, int *offp,
     	/*
     	 * Not for us; forward if possible and desirable.
     	 */
    -	if (ipforwarding == 0) {
    +	if (!ISSET(flags, IP_FORWARDING)) {
     		ipstat_inc(ips_cantforward);
     		goto bad;
     	}
    @@ -585,7 +599,7 @@ ip_input_if(struct mbuf **mp, int *offp,
     	}
     #endif /* IPSEC */
     
    -	ip_forward(m, ifp, &ro, pfrdr);
    +	ip_forward(m, ifp, &ro, flags);
     	*mp = NULL;
     	rtfree(ro.ro_rt);
     	return IPPROTO_DONE;
    @@ -807,7 +821,7 @@ ip_deliver(struct mbuf **mp, int *offp, 
     #undef IPSTAT_INC
     
     int
    -in_ouraddr(struct mbuf *m, struct ifnet *ifp, struct route *ro)
    +in_ouraddr(struct mbuf *m, struct ifnet *ifp, struct route *ro, int flags)
     {
     	struct rtentry		*rt;
     	struct ip		*ip;
    @@ -837,7 +851,8 @@ in_ouraddr(struct mbuf *m, struct ifnet 
     		 * if it is received on the interface with that address.
     		 */
     		if (ISSET(rt->rt_flags, RTF_BROADCAST) &&
    -		    (!ip_directedbcast || rt->rt_ifidx == ifp->if_index)) {
    +		    (!ISSET(flags, IP_ALLOWBROADCAST) ||
    +		    rt->rt_ifidx == ifp->if_index)) {
     			match = 1;
     
     			/* Make sure M_BCAST is set */
    @@ -876,7 +891,8 @@ in_ouraddr(struct mbuf *m, struct ifnet 
     				break;
     			}
     		}
    -	} else if (ipforwarding == 0 && rt->rt_ifidx != ifp->if_index &&
    +	} else if (!ISSET(flags, IP_FORWARDING) &&
    +	    rt->rt_ifidx != ifp->if_index &&
     	    !((ifp->if_flags & IFF_LOOPBACK) || (ifp->if_type == IFT_ENC) ||
     	    (m->m_pkthdr.pf.flags & PF_TAG_TRANSLATE_LOCALHOST))) {
     		/* received on wrong interface. */
    @@ -1132,11 +1148,13 @@ ip_slowtimo(void)
     void
     ip_flush(void)
     {
    -	int max = 50;
    +	int limit, max = 50;
     
     	MUTEX_ASSERT_LOCKED(&ipq_mutex);
     
    -	while (!LIST_EMPTY(&ipq) && ip_frags > ip_maxqueue * 3 / 4 && --max) {
    +	limit = ip_maxqueue * 3 / 4;
    +
    +	while (!LIST_EMPTY(&ipq) && ip_frags > limit && --max) {
     		ipstat_inc(ips_fragdropped);
     		ip_freef(LIST_FIRST(&ipq));
     	}
    @@ -1150,7 +1168,7 @@ ip_flush(void)
      * 0 if the packet should be processed further.
      */
     int
    -ip_dooptions(struct mbuf *m, struct ifnet *ifp)
    +ip_dooptions(struct mbuf *m, struct ifnet *ifp, int flags)
     {
     	struct ip *ip = mtod(m, struct ip *);
     	unsigned int rtableid = m->m_pkthdr.ph_rtableid;
    @@ -1371,8 +1389,8 @@ ip_dooptions(struct mbuf *m, struct ifne
     		}
     	}
     	KERNEL_UNLOCK();
    -	if (forward && ipforwarding > 0) {
    -		ip_forward(m, ifp, NULL, 1);
    +	if (forward && ISSET(flags, IP_FORWARDING)) {
    +		ip_forward(m, ifp, NULL, flags | IP_REDIRECT);
     		return (1);
     	}
     	return (0);
    @@ -1514,7 +1532,7 @@ const u_char inetctlerrmap[PRC_NCMDS] = 
      * of codes and types.
      *
      * If not forwarding, just drop the packet.  This could be confusing
    - * if ipforwarding was zero but some routing protocol was advancing
    + * if ip_forwarding was zero but some routing protocol was advancing
      * us as a gateway to somewhere.  However, we must let the routing
      * protocol deal with that.
      *
    @@ -1522,7 +1540,7 @@ const u_char inetctlerrmap[PRC_NCMDS] = 
      * via a source route.
      */
     void
    -ip_forward(struct mbuf *m, struct ifnet *ifp, struct route *ro, int srcrt)
    +ip_forward(struct mbuf *m, struct ifnet *ifp, struct route *ro, int flags)
     {
     	struct mbuf mfake, *mcopy;
     	struct ip *ip = mtod(m, struct ip *);
    @@ -1588,7 +1606,7 @@ ip_forward(struct mbuf *m, struct ifnet 
     	if ((rt->rt_ifidx == ifp->if_index) &&
     	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
     	    satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
    -	    ipsendredirects && !srcrt &&
    +	    ip_sendredirects && !ISSET(flags, IP_REDIRECT) &&
     	    !arpproxy(satosin(rt_key(rt))->sin_addr, m->m_pkthdr.ph_rtableid)) {
     		if ((ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_netmask) ==
     		    ifatoia(rt->rt_ifa)->ia_net) {
    @@ -1602,9 +1620,7 @@ ip_forward(struct mbuf *m, struct ifnet 
     		}
     	}
     
    -	error = ip_output(m, NULL, ro,
    -	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
    -	    NULL, NULL, 0);
    +	error = ip_output(m, NULL, ro, flags | IP_FORWARDING, NULL, NULL, 0);
     	rt = ro->ro_rt;
     	if (error)
     		ipstat_inc(ips_cantforward);
    @@ -1781,10 +1797,8 @@ ip_sysctl(int *name, u_int namelen, void
     		NET_UNLOCK();
     		return (error);
     	default:
    -		NET_LOCK();
     		error = sysctl_bounded_arr(ipctl_vars, nitems(ipctl_vars),
     		    name, namelen, oldp, oldlenp, newp, newlen);
    -		NET_UNLOCK();
     		return (error);
     	}
     	/* NOTREACHED */
    Index: netinet/ip_ipip.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_ipip.c,v
    diff -u -p -r1.101 ip_ipip.c
    --- netinet/ip_ipip.c	11 Feb 2024 01:27:45 -0000	1.101
    +++ netinet/ip_ipip.c	16 May 2024 19:22:05 -0000
    @@ -481,7 +481,7 @@ ipip_output(struct mbuf **mp, struct tdb
     		ip6o->ip6_vfc &= ~IPV6_VERSION_MASK;
     		ip6o->ip6_vfc |= IPV6_VERSION;
     		ip6o->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6o));
    -		ip6o->ip6_hlim = ip_defttl;
    +		ip6o->ip6_hlim = ip6_defhlim;
     		in6_embedscope(&ip6o->ip6_src, &tdb->tdb_src.sin6, NULL, NULL);
     		in6_embedscope(&ip6o->ip6_dst, &tdb->tdb_dst.sin6, NULL, NULL);
     
    Index: netinet/ip_mroute.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_mroute.c,v
    diff -u -p -r1.142 ip_mroute.c
    --- netinet/ip_mroute.c	6 Apr 2024 14:23:27 -0000	1.142
    +++ netinet/ip_mroute.c	16 May 2024 19:22:05 -0000
    @@ -98,7 +98,7 @@ int mcast_debug = 1;
     struct socket	*ip_mrouter[RT_TABLEID_MAX + 1];
     struct rttimer_queue ip_mrouterq;
     uint64_t	 mrt_count[RT_TABLEID_MAX + 1];
    -int		ip_mrtproto = IGMP_DVMRP;    /* for netstat only */
    +int		ip_mrtproto = IGMP_DVMRP;    /* [I] for netstat only */
     
     struct mrtstat	mrtstat;
     
    Index: netinet/ip_output.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_output.c,v
    diff -u -p -r1.399 ip_output.c
    --- netinet/ip_output.c	16 May 2024 13:01:04 -0000	1.399
    +++ netinet/ip_output.c	16 May 2024 19:22:05 -0000
    @@ -326,7 +326,7 @@ reroute:
     			 * above, will be forwarded by the ip_input() routine,
     			 * if necessary.
     			 */
    -			if (ipmforwarding && ip_mrouter[ifp->if_rdomain] &&
    +			if (ip_mforwarding && ip_mrouter[ifp->if_rdomain] &&
     			    (flags & IP_FORWARDING) == 0) {
     				int rv;
     
    @@ -428,7 +428,7 @@ sendit:
     #endif
     
     #ifdef IPSEC
    -	if ((flags & IP_FORWARDING) && ipforwarding == 2 &&
    +	if ((flags & IP_FORWARDING) && ip_forwarding == 2 &&
     	    (!ipsec_in_use ||
     	    m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) == NULL)) {
     		error = EHOSTUNREACH;
    Index: netinet/ip_var.h
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_var.h,v
    diff -u -p -r1.117 ip_var.h
    --- netinet/ip_var.h	17 Apr 2024 20:48:51 -0000	1.117
    +++ netinet/ip_var.h	16 May 2024 19:22:05 -0000
    @@ -206,26 +206,26 @@ struct ipoffnxt {
     /* flags passed to ip_output */
     #define	IP_FORWARDING		0x1		/* most of ip header exists */
     #define	IP_RAWOUTPUT		0x2		/* raw ip header exists */
    +#define	IP_REDIRECT		0x4	/* redirected by pf or source route */
     #define	IP_ALLOWBROADCAST	SO_BROADCAST	/* can send broadcast packets */
     #define	IP_MTUDISC		0x0800		/* pmtu discovery, set DF */
     
     extern struct ipstat ipstat;
    -extern int ip_defttl;			/* default IP ttl */
    +extern volatile int ip_defttl;		/* default IP ttl */
     
     #define IPMTUDISCTIMEOUT (10 * 60)	/* as per RFC 1191 */
     
     extern int ip_mtudisc;			/* mtu discovery */
     extern int ip_mtudisc_timeout;		/* seconds to timeout mtu discovery */
     
    -extern int ipport_firstauto;		/* min port for port allocation */
    -extern int ipport_lastauto;		/* max port for port allocation */
    -extern int ipport_hifirstauto;		/* min dynamic/private port number */
    -extern int ipport_hilastauto;		/* max dynamic/private port number */
    -extern int ipforwarding;		/* enable IP forwarding */
    -#ifdef MROUTING
    -extern int ipmforwarding;		/* enable multicast forwarding */
    -#endif
    +extern volatile int ipport_firstauto;	/* min port for port allocation */
    +extern volatile int ipport_lastauto;	/* max port for port allocation */
    +extern volatile int ipport_hifirstauto;	/* min dynamic/private port number */
    +extern volatile int ipport_hilastauto;	/* max dynamic/private port number */
    +extern volatile int ip_forwarding;	/* enable IP forwarding */
    +extern volatile int ip_mforwarding;	/* enable multicast forwarding */
     extern int ipmultipath;			/* enable multipath routing */
    +extern volatile int ip_directedbcast;	/* accept all broadcast packets */
     extern unsigned int la_hold_total;
     
     extern const struct pr_usrreqs rip_usrreqs;
    Index: netinet6/ip6_forward.c
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/ip6_forward.c,v
    diff -u -p -r1.117 ip6_forward.c
    --- netinet6/ip6_forward.c	16 Apr 2024 12:56:39 -0000	1.117
    +++ netinet6/ip6_forward.c	16 May 2024 19:22:05 -0000
    @@ -75,7 +75,7 @@
      * of codes and types.
      *
      * If not forwarding, just drop the packet.  This could be confusing
    - * if ipforwarding was zero but some routing protocol was advancing
    + * if ip6_forwarding was zero but some routing protocol was advancing
      * us as a gateway to somewhere.  However, we must let the routing
      * protocol deal with that.
      *
    Index: sys/sysctl.h
    ===================================================================
    RCS file: /data/mirror/openbsd/cvs/src/sys/sys/sysctl.h,v
    diff -u -p -r1.235 sysctl.h
    --- sys/sysctl.h	1 Oct 2023 15:58:12 -0000	1.235
    +++ sys/sysctl.h	16 May 2024 19:22:05 -0000
    @@ -1035,7 +1035,7 @@ struct ctldebug {
      */
     struct sysctl_bounded_args {
     	int mib;     /* identifier shared with userspace as a CTL_ #define */
    -	int *var;    /* never NULL */
    +	volatile int *var;    /* never NULL */
     	int minimum; /* checking is disabled if minimum == maximum  */
     	int maximum; /* read-only variable if minimum > maximum */
     };
    @@ -1058,7 +1058,8 @@ int sysctl_int_lower(void *, size_t *, v
     int sysctl_int(void *, size_t *, void *, size_t, int *);
     int sysctl_rdint(void *, size_t *, void *, int);
     int sysctl_securelevel_int(void *, size_t *, void *, size_t, int *);
    -int sysctl_int_bounded(void *, size_t *, void *, size_t, int *, int, int);
    +int sysctl_int_bounded(void *, size_t *, void *, size_t, volatile int *,
    +    int, int);
     int sysctl_bounded_arr(const struct sysctl_bounded_args *, u_int,
         int *, u_int, void *, size_t *, void *, size_t);
     int sysctl_quad(void *, size_t *, void *, size_t, int64_t *);
    
    
    
  • Mark Kettenis:

    ip sysctl atomic