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MFC 1.145:

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Rework ARP retransmission algorythm so that ARP requests are
  retransmitted without suppression, while there is demand for
  such ARP entry. As before, retransmission is rate limited to
  one packet per second. Details:
    - Remove net.link.ether.inet.host_down_time
    - Do not set/clear RTF_REJECT flag on route, to
      avoid rt_check() returning error. We will generate error
      ourselves.
    - Return EWOULDBLOCK on first arp_maxtries failed
      requests , and return EHOSTDOWN/EHOSTUNREACH
      on further requests.
    - Retransmit ARP request always, independently from return
      code. Ratelimit to 1 pps.

MFC 1.142:
  Use monotonic 'time_uptime' instead of 'time_second' as timebase
  for rt->rt_rmx.rmx_expire.
This commit is contained in:
glebius 2005-11-25 14:38:19 +00:00
parent 5baa2f368f
commit 630273a7cf
1 changed files with 28 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
sys/netinet/if_ether.c
View File

@ -81,14 +81,11 @@ SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
/* timer values */
static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
static int arpt_down = 20; /* once declared down, don't send for 20 sec */
SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
&arpt_prune, 0, "");
SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
&arpt_keep, 0, "");
SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
&arpt_down, 0, "");
#define rt_expire rt_rmx.rmx_expire
@ -97,8 +94,7 @@ struct llinfo_arp {
struct rtentry *la_rt;
struct mbuf *la_hold; /* last packet until resolved/timeout */
u_short la_preempt; /* countdown for pre-expiry arps */
u_short la_asked; /* #times we QUERIED following expiration */
#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */
u_short la_asked; /* # requests sent */
};
static LIST_HEAD(, llinfo_arp) llinfo_arp;
@ -152,7 +148,6 @@ arptimer(void * __unused unused)
if (rt->rt_refcnt > 1) {
sdl->sdl_alen = 0;
la->la_preempt = la->la_asked = 0;
rt->rt_flags &= ~RTF_REJECT;
RT_UNLOCK(rt);
continue;
}
@ -450,8 +445,7 @@ arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
/*
* If entry has an expiry time and it is approaching,
* see if we need to send an ARP request within this
* arpt_down interval.
* send an ARP request.
*/
if ((rt->rt_expire != 0) &&
(time_second + la->la_preempt > rt->rt_expire)) {
@ -487,29 +481,33 @@ arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
if (la->la_hold)
m_freem(la->la_hold);
la->la_hold = m;
if (rt->rt_expire) {
rt->rt_flags &= ~RTF_REJECT;
if (la->la_asked == 0 || rt->rt_expire != time_second) {
rt->rt_expire = time_second;
if (la->la_asked++ < arp_maxtries) {
struct in_addr sin =
SIN(rt->rt_ifa->ifa_addr)->sin_addr;
RT_UNLOCK(rt);
arprequest(ifp, &sin, &SIN(dst)->sin_addr,
IF_LLADDR(ifp));
return (EWOULDBLOCK);
} else {
rt->rt_flags |= RTF_REJECT;
rt->rt_expire += arpt_down;
la->la_asked = 0;
la->la_preempt = arp_maxtries;
}
KASSERT(rt->rt_expire > 0, ("sending ARP request for static entry"));
}
}
RT_UNLOCK(rt);
return (EWOULDBLOCK);
/*
* Return EWOULDBLOCK if we have tried less than arp_maxtries. It
* will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
* if we have already sent arp_maxtries ARP requests. Retransmit the
* ARP request, but not faster than one request per second.
*/
if (la->la_asked < arp_maxtries)
error = EWOULDBLOCK; /* First request. */
else
error = (rt == rt0) ? EHOSTDOWN : EHOSTUNREACH;
if (la->la_asked++ == 0 || rt->rt_expire != time_uptime) {
struct in_addr sin =
SIN(rt->rt_ifa->ifa_addr)->sin_addr;
rt->rt_expire = time_uptime;
RT_UNLOCK(rt);
arprequest(ifp, &sin, &SIN(dst)->sin_addr,
IF_LLADDR(ifp));
} else
RT_UNLOCK(rt);
return (error);
}
/*
@ -787,8 +785,7 @@ in_arpinput(m)
th->rcf = trld->trld_rcf;
}
if (rt->rt_expire)
rt->rt_expire = time_second + arpt_keep;
rt->rt_flags &= ~RTF_REJECT;
rt->rt_expire = time_uptime + arpt_keep;
la->la_asked = 0;
la->la_preempt = arp_maxtries;
hold = la->la_hold;