[src/trunk]: src/usr.sbin/ifwatchd ifwatchd: Enable SO_RERROR to re-sync inte...

[roy <roy%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e3ce0f2df71e
branches:  trunk
changeset: 940156:e3ce0f2df71e
user:      roy <roy%NetBSD.org@localhost>
date:      Sun Oct 04 20:36:32 2020 +0000

description:
ifwatchd: Enable SO_RERROR to re-sync interface state.

Interface arrival, departure and link state changes will sync
and if different will be actioned.

Currently we do not track addresses, so any changes there are still lost.

diffstat:

 usr.sbin/ifwatchd/ifwatchd.c |  100 +++++++++++++++++++++++++++++++-----------
 1 files changed, 73 insertions(+), 27 deletions(-)

diffs (189 lines):

diff -r a46af9640484 -r e3ce0f2df71e usr.sbin/ifwatchd/ifwatchd.c
--- a/usr.sbin/ifwatchd/ifwatchd.c      Sun Oct 04 20:23:32 2020 +0000
+++ b/usr.sbin/ifwatchd/ifwatchd.c      Sun Oct 04 20:36:32 2020 +0000
@@ -1,6 +1,6 @@
-/*     $NetBSD: ifwatchd.c,v 1.45 2020/09/27 19:55:21 roy Exp $        */
+/*     $NetBSD: ifwatchd.c,v 1.46 2020/10/04 20:36:32 roy Exp $        */
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: ifwatchd.c,v 1.45 2020/09/27 19:55:21 roy Exp $");
+__RCSID("$NetBSD: ifwatchd.c,v 1.46 2020/10/04 20:36:32 roy Exp $");
 
 /*-
  * Copyright (c) 2002, 2003 The NetBSD Foundation, Inc.
@@ -44,15 +44,16 @@
 #include <netinet/in_var.h>
 #include <arpa/inet.h>
 
+#include <err.h>
+#include <errno.h>
+#include <ifaddrs.h>
+#include <netdb.h>
 #include <paths.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <syslog.h>
 #include <unistd.h>
-#include <netdb.h>
-#include <err.h>
-#include <ifaddrs.h>
-#include <syslog.h>
 
 enum event { ARRIVAL, DEPARTURE, UP, DOWN, CARRIER, NO_CARRIER };
 enum addrflag { NOTREADY, DETACHED, READY };
@@ -69,7 +70,7 @@
 static void check_carrier(const struct if_msghdr *ifm);
 static void free_interfaces(void);
 static struct interface_data * find_interface(int index);
-static void run_initial_ups(void);
+static void run_initial_ups(bool);
 
 /* global variables */
 static int verbose = 0, quiet = 0;
@@ -197,9 +198,12 @@
        if (setsockopt(s, PF_ROUTE, RO_MSGFILTER,
            &msgfilter, sizeof(msgfilter)) < 0)
                syslog(LOG_ERR, "RO_MSGFILTER: %m");
+       n = 1;
+       if (setsockopt(s, SOL_SOCKET, SO_RERROR, &n, sizeof(n)) < 0)
+               syslog(LOG_ERR, "SO_RERROR: %m");
 
        if (!inhibit_initial)
-               run_initial_ups();
+               run_initial_ups(true);
 
        iov[0].iov_base = buf;
        iov[0].iov_len = sizeof(buf);
@@ -210,6 +214,15 @@
        for (;;) {
                n = recvmsg(s, &msg, 0);
                if (n == -1) {
+                       if (errno == ENOBUFS) {
+                               syslog(LOG_ERR,
+                                   "routing socket overflow detected");
+                               /* XXX We don't track addresses, so they
+                                * won't be reported. */
+                               if (!inhibit_initial)
+                                       run_initial_ups(false);
+                               continue;
+                       }
                        syslog(LOG_ERR, "recvmsg: %m");
                        exit(EXIT_FAILURE);
                }
@@ -482,6 +495,28 @@
 }
 
 static void
+do_announce(struct interface_data *ifd,
+    unsigned short what, unsigned short index)
+{
+
+       switch (what) {
+       case IFAN_ARRIVAL:
+               ifd->index = index;
+               invoke_script(ifd->ifname, ARRIVAL, NULL, NULL);
+               break;
+       case IFAN_DEPARTURE:
+               ifd->index = -1;
+               ifd->last_carrier_status = -1;
+               invoke_script(ifd->ifname, DEPARTURE, NULL, NULL);
+               break;
+       default:
+               if (verbose)
+                       (void) printf("unknown announce: what=%d\n", what);
+               break;
+       }
+}
+
+static void
 check_announce(const struct if_announcemsghdr *ifan)
 {
        struct interface_data * p;
@@ -491,22 +526,7 @@
                if (strcmp(p->ifname, ifname) != 0)
                        continue;
 
-               switch (ifan->ifan_what) {
-               case IFAN_ARRIVAL:
-                       p->index = ifan->ifan_index;
-                       invoke_script(p->ifname, ARRIVAL, NULL, NULL);
-                       break;
-               case IFAN_DEPARTURE:
-                       p->index = -1;
-                       p->last_carrier_status = -1;
-                       invoke_script(p->ifname, DEPARTURE, NULL, NULL);
-                       break;
-               default:
-                       if (verbose)
-                               (void) printf("unknown announce: "
-                                   "what=%d\n", ifan->ifan_what);
-                       break;
-               }
+               do_announce(p, ifan->ifan_what, ifan->ifan_index);
                return;
        }
 }
@@ -536,7 +556,7 @@
 }
 
 static void
-run_initial_ups(void)
+run_initial_ups(bool do_addrs)
 {
        struct interface_data * ifd;
        struct ifaddrs *res = NULL, *p;
@@ -551,6 +571,19 @@
        if (getifaddrs(&res) != 0)
                goto out;
 
+       /* Check if any interfaces vanished */
+       SLIST_FOREACH(ifd, &ifs, next) {
+               for (p = res; p; p = p->ifa_next) {
+                       if (strcmp(ifd->ifname, p->ifa_name) != 0)
+                               continue;
+                       ifa = p->ifa_addr;
+                       if (ifa != NULL && ifa->sa_family == AF_LINK)
+                               break;
+               }
+               if (p == NULL)
+                       do_announce(ifd, IFAN_DEPARTURE, ifd->index);
+       }
+
        for (p = res; p; p = p->ifa_next) {
                SLIST_FOREACH(ifd, &ifs, next) {
                        if (strcmp(ifd->ifname, p->ifa_name) == 0)
@@ -560,7 +593,8 @@
                        continue;
 
                ifa = p->ifa_addr;
-               if (ifa != NULL && ifa->sa_family == AF_LINK)
+               if (ifa != NULL && ifa->sa_family == AF_LINK &&
+                   ifd->index == -1)
                        invoke_script(ifd->ifname, ARRIVAL, NULL, NULL);
 
                if ((p->ifa_flags & IFF_UP) == 0)
@@ -569,11 +603,23 @@
                        continue;
                if (ifa->sa_family == AF_LINK) {
                        ifi = (const struct if_data *)p->ifa_data;
-                       if (ifi->ifi_link_state == LINK_STATE_UP)
+                       if (ifd->last_carrier_status == ifi->ifi_link_state)
+                               continue;
+                       switch (ifi->ifi_link_state) {
+                       case LINK_STATE_UP:
                                invoke_script(ifd->ifname, CARRIER, NULL, NULL);
+                               break;
+                       case LINK_STATE_DOWN:
+                               if (ifd->last_carrier_status == -1)
+                                       break;
+                               invoke_script(ifd->ifname, CARRIER, NULL, NULL);
+                               break;
+                       }
                        ifd->last_carrier_status = ifi->ifi_link_state;
                        continue;
                }
+               if (!do_addrs)
+                       continue;
                aflag = check_addrflags(ifa->sa_family, p->ifa_addrflags);
                if (aflag != READY)
                        continue;