Implement arp_drain(), which frees packets tied up in the arp cache if
mbufs are in short supply. Create a (trivial) protocol domain for arp so that the drain routine will be called from m_reclaim()
This commit is contained in:
sommerfeld
parent
b8e4538f80
commit
2aa9696fee
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@ -1,4 +1,4 @@
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/* $NetBSD: uipc_domain.c,v 1.27 1999/07/09 22:57:16 thorpej Exp $ */
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/* $NetBSD: uipc_domain.c,v 1.28 1999/08/05 04:04:28 sommerfeld Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1993
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@ -42,6 +42,7 @@
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#include "opt_iso.h"
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#include "opt_ns.h"
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#include "opt_natm.h"
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#include "arp.h"
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#include <sys/param.h>
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#include <sys/socket.h>
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@ -108,6 +109,9 @@ domaininit()
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#endif
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#ifdef IPSEC
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ADDDOMAIN(key);
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#endif
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#if NARP > 0
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ADDDOMAIN(arp);
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#endif
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ADDDOMAIN(route);
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#endif /* ! lint */
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@ -1,4 +1,4 @@
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/* $NetBSD: if_arp.c,v 1.62 1999/06/18 18:20:50 thorpej Exp $ */
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/* $NetBSD: if_arp.c,v 1.63 1999/08/05 04:04:29 sommerfeld Exp $ */
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/*-
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* Copyright (c) 1998 The NetBSD Foundation, Inc.
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@ -94,6 +94,8 @@
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#include <sys/ioctl.h>
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#include <sys/syslog.h>
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#include <sys/proc.h>
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#include <sys/protosw.h>
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#include <sys/domain.h>
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#include <net/ethertypes.h>
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#include <net/if.h>
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@ -102,6 +104,7 @@
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#include <net/if_types.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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@ -193,6 +196,123 @@ lla_snprintf(adrp, len)
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return buf;
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}
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struct protosw arpsw[] = {
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{ 0, 0, 0, 0,
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0, 0, 0, 0,
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0,
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0, 0, 0, arp_drain,
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}
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};
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struct domain arpdomain =
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{ PF_ARP, "arp", 0, 0, 0,
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arpsw, &arpsw[sizeof(arpsw)/sizeof(arpsw[0])]
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};
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/*
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* ARP table locking.
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*
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* to prevent lossage vs. the arp_drain routine (which may be called at
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* any time, including in a device driver context), we do two things:
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*
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* 1) manipulation of la->la_hold is done at splimp() (for all of
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* about two instructions).
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*
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* 2) manipulation of the arp table's linked list is done under the
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* protection of the ARP_LOCK; if arp_drain() or arptimer is called
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* while the arp table is locked, we punt and try again later.
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*/
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int arp_locked;
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static __inline int arp_lock_try __P((int));
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static __inline void arp_unlock __P((void));
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static __inline int
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arp_lock_try(int recurse)
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{
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int s;
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s = splimp();
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if (!recurse && arp_locked) {
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splx(s);
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return (0);
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}
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arp_locked++;
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splx(s);
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return (1);
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}
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static __inline void
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arp_unlock()
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{
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int s;
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s = splimp();
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arp_locked--;
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splx(s);
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}
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#ifdef DIAGNOSTIC
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#define ARP_LOCK(recurse) \
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do { \
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if (arp_lock_try(recurse) == 0) { \
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printf("%s:%d: arp already locked\n", __FILE__, __LINE__); \
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panic("arp_lock"); \
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} \
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} while (0)
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#define ARP_LOCK_CHECK() \
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do { \
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if (arp_locked == 0) { \
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printf("%s:%d: arp lock not held\n", __FILE__, __LINE__); \
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panic("arp lock check"); \
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} \
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} while (0)
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#else
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#define ARP_LOCK(x) (void) arp_lock_try(x)
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#define ARP_LOCK_CHECK() /* nothing */
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#endif
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#define ARP_UNLOCK() arp_unlock()
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/*
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* ARP protocol drain routine. Called when memory is in short supply.
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* Called at splimp();
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*/
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void
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arp_drain()
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{
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register struct llinfo_arp *la, *nla;
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int count = 0;
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struct mbuf *mold;
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printf("arp_drain: entered\n");
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if (arp_lock_try(0) == 0) {
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printf("arp_drain: locked; punting\n");
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return;
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}
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for (la = llinfo_arp.lh_first; la != 0; la = nla) {
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nla = la->la_list.le_next;
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mold = la->la_hold;
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la->la_hold = 0;
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if (mold) {
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m_freem(mold);
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count++;
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}
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}
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ARP_UNLOCK();
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printf("arp_drain: freed %d\n", count);
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}
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/*
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* Timeout routine. Age arp_tab entries periodically.
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*/
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@ -205,6 +325,13 @@ arptimer(arg)
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register struct llinfo_arp *la, *nla;
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s = splsoftnet();
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if (arp_lock_try(0) == 0) {
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/* get it later.. */
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splx(s);
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return;
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}
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timeout(arptimer, NULL, arpt_prune * hz);
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for (la = llinfo_arp.lh_first; la != 0; la = nla) {
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register struct rtentry *rt = la->la_rt;
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@ -213,6 +340,9 @@ arptimer(arg)
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if (rt->rt_expire && rt->rt_expire <= time.tv_sec)
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arptfree(la); /* timer has expired; clear */
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}
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ARP_UNLOCK();
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splx(s);
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}
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@ -229,6 +359,8 @@ arp_rtrequest(req, rt, sa)
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register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
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static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
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size_t allocsize;
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struct mbuf *mold;
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int s;
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if (!arpinit_done) {
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arpinit_done = 1;
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@ -243,6 +375,9 @@ arp_rtrequest(req, rt, sa)
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}
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if (rt->rt_flags & RTF_GATEWAY)
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return;
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ARP_LOCK(1); /* we may already be locked here. */
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switch (req) {
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case RTM_ADD:
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@ -344,10 +479,18 @@ arp_rtrequest(req, rt, sa)
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LIST_REMOVE(la, la_list);
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rt->rt_llinfo = 0;
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rt->rt_flags &= ~RTF_LLINFO;
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if (la->la_hold)
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m_freem(la->la_hold);
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s = splimp();
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mold = la->la_hold;
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la->la_hold = 0;
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splx(s);
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if (mold)
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m_freem(mold);
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Free((caddr_t)la);
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}
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ARP_UNLOCK();
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}
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/*
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@ -407,7 +550,9 @@ arpresolve(ifp, rt, m, dst, desten)
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{
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register struct llinfo_arp *la;
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struct sockaddr_dl *sdl;
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struct mbuf *mold;
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int s;
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if (rt)
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la = (struct llinfo_arp *)rt->rt_llinfo;
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else {
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@ -435,9 +580,16 @@ arpresolve(ifp, rt, m, dst, desten)
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* response yet. Replace the held mbuf with this
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* latest one.
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*/
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if (la->la_hold)
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m_freem(la->la_hold);
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s = splimp();
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mold = la->la_hold;
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la->la_hold = m;
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splx(s);
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if (mold)
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m_freem(mold);
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/*
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* Re-send the ARP request when appropriate.
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*/
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@ -523,12 +675,15 @@ in_arpinput(m)
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struct arphdr *ah;
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register struct ifnet *ifp = m->m_pkthdr.rcvif;
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register struct llinfo_arp *la = 0;
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register struct rtentry *rt;
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register struct rtentry *rt;
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struct in_ifaddr *ia;
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struct sockaddr_dl *sdl;
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struct sockaddr sa;
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struct in_addr isaddr, itaddr, myaddr;
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int op;
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struct mbuf *mold;
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int s;
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ah = mtod(m, struct arphdr *);
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op = ntohs(ah->ar_op);
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@ -670,11 +825,14 @@ in_arpinput(m)
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rt->rt_expire = time.tv_sec + arpt_keep;
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rt->rt_flags &= ~RTF_REJECT;
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la->la_asked = 0;
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if (la->la_hold) {
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(*ifp->if_output)(ifp, la->la_hold,
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rt_key(rt), rt);
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la->la_hold = 0;
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}
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s = splimp();
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mold = la->la_hold;
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la->la_hold = 0;
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splx(s);
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if (mold)
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(*ifp->if_output)(ifp, mold, rt_key(rt), rt);
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}
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reply:
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if (op != ARPOP_REQUEST) {
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@ -719,6 +877,8 @@ arptfree(la)
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register struct rtentry *rt = la->la_rt;
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register struct sockaddr_dl *sdl;
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ARP_LOCK_CHECK();
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if (rt == 0)
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panic("arptfree");
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if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
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@ -1066,3 +1226,4 @@ db_show_arptab()
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}
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#endif
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#endif /* INET */
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@ -1,4 +1,4 @@
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/* $NetBSD: if_inarp.h,v 1.28 1999/02/21 15:17:14 drochner Exp $ */
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/* $NetBSD: if_inarp.h,v 1.29 1999/08/05 04:04:29 sommerfeld Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1993
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@ -70,6 +70,8 @@ void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *));
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int arpresolve __P((struct ifnet *, struct rtentry *, struct mbuf *,
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struct sockaddr *, u_char *));
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void arpintr __P((void));
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void arp_drain __P((void));
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int arpioctl __P((u_long, caddr_t));
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void arpwhohas __P((struct ifnet *, struct in_addr *));
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