ra: align RA update interval with RFC4861 (FS#964)

RFC4861 paragraph 6.2.1 states the minimum allowed time between sending
unsolicited multicast Router Advertisements is 3 seconds.
Align the odhcp6c implementation to this requirement as before Router
Advertisement updates were accepted each 30 seconds.
This lead to IPv6 connectivity issues when a network sends Router
Advertisements with an interval smaller than 30 seconds as reported
in FS#964.
While at it rework the RA update logic making it clear the -m option
is only related to RA updates.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 58050dc45b236c2d1446289bf6c3fe5af3da7cb8..9dce577250400b29a0dde12841d6b7ea0ba90882 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -1277,7 +1277,7 @@ static int dhcpv6_parse_ia(void *opt, void *end)
                        }
 
                        if (ok) {
-                               odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
+                               odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0);
                                parsed_ia++;
                        }
 
@@ -1302,7 +1302,7 @@ static int dhcpv6_parse_ia(void *opt, void *end)
                        entry.length = 128;
                        entry.target = addr->addr;
 
-                       odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
+                       odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0);
                        parsed_ia++;
                }
        }

diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index 6e83c40c712a10b342434531ce34d575e31167ea..666af5c398493f07f97d6d775bbd65755c869171 100644 (file)
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -57,7 +57,6 @@ static bool bound = false, release = true, ra = false;
 static time_t last_update = 0;
 static char *ifname = NULL;
 
-static unsigned int min_update_interval = DEFAULT_MIN_UPDATE_INTERVAL;
 static unsigned int script_sync_delay = 10;
 static unsigned int script_accu_delay = 1;
 
@@ -82,6 +81,7 @@ int main(_unused int argc, char* const argv[])
        int c;
        unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
        unsigned int ra_options = RA_RDNSS_DEFAULT_LIFETIME;
+       unsigned int ra_holdoff_interval = RA_MIN_ADV_INTERVAL;
 
        while ((c = getopt(argc, argv, "S::N:V:P:FB:c:i:r:Ru:s:kt:m:Lhedp:fav")) != -1) {
                switch (c) {
@@ -195,7 +195,7 @@ int main(_unused int argc, char* const argv[])
                        break;
 
                case 'm':
-                       min_update_interval = atoi(optarg);
+                       ra_holdoff_interval = atoi(optarg);
                        break;
 
                case 'L':
@@ -253,7 +253,7 @@ int main(_unused int argc, char* const argv[])
 
        if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
                        init_dhcpv6(ifname, client_options, sol_timeout) ||
-                       ra_init(ifname, &ifid, ra_options) ||
+                       ra_init(ifname, &ifid, ra_options, ra_holdoff_interval) ||
                        script_init(script, ifname)) {
                syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
                return 3;
@@ -456,7 +456,7 @@ static int usage(void)
        "       -f              Don't send Client FQDN option\n"
        "       -k              Don't send a RELEASE when stopping\n"
        "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
-       "       -m <seconds>    Minimum time between accepting updates (30)\n"
+       "       -m <seconds>    Minimum time between accepting RA updates (3)\n"
        "       -L              Ignore default lifetime for RDNSS records\n"
        "\nInvocation options:\n"
        "       -p <pidfile>    Set pidfile (/var/run/odhcp6c.pid)\n"
@@ -597,7 +597,7 @@ static struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const
 }
 
 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new,
-               uint32_t safe, bool filterexcess)
+               uint32_t safe, unsigned int holdoff_interval)
 {
        size_t len;
        struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
@@ -608,12 +608,12 @@ bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new,
 
        if (new->valid > 0) {
                if (x) {
-                       if (filterexcess && new->valid >= x->valid &&
+                       if (holdoff_interval && new->valid >= x->valid &&
                                        new->valid != UINT32_MAX &&
-                                       new->valid - x->valid < min_update_interval &&
+                                       new->valid - x->valid < holdoff_interval &&
                                        new->preferred >= x->preferred &&
                                        new->preferred != UINT32_MAX &&
-                                       new->preferred - x->preferred < min_update_interval)
+                                       new->preferred - x->preferred < holdoff_interval)
                                return false;
 
                        x->valid = new->valid;

diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index e55d3c1a988d2622fbe26fb6b66132b9e9d89ae2..1d9bd3e6e554921d374cd54d228b0807579e7d0d 100644 (file)
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -32,7 +32,7 @@
 #define DHCPV6_REB_MAX_RT 600
 #define DHCPV6_INF_MAX_RT 120
 
-#define DEFAULT_MIN_UPDATE_INTERVAL 30
+#define RA_MIN_ADV_INTERVAL 3   /* RFC 4861 paragraph 6.2.1 */
 
 enum dhcvp6_opt {
        DHCPV6_OPT_CLIENTID = 1,
@@ -356,7 +356,8 @@ void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len);
 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len);
 
 // Entry manipulation
-bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe, bool filterexcess);
+bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new,
+                               uint32_t safe, unsigned int holdoff_interval);
 
 void odhcp6c_expire(void);
 uint32_t odhcp6c_elapsed(void);

diff --git a/src/ra.c b/src/ra.c
index d6a2158257bac23b8c2dc4ebb694b71e66d2eaa9..40188b61a37823e6e4a4e6ca535814bb479c86e3 100644 (file)
--- a/src/ra.c
+++ b/src/ra.c
@@ -56,6 +56,7 @@ static char if_name[IF_NAMESIZE] = {0};
 static volatile int rs_attempt = 0;
 static struct in6_addr lladdr = IN6ADDR_ANY_INIT;
 static unsigned int ra_options = 0;
+static unsigned int ra_holdoff_interval = 0;
 
 struct {
        struct icmp6_hdr hdr;
@@ -67,9 +68,11 @@ struct {
 
 static void ra_send_rs(int signal __attribute__((unused)));
 
-int ra_init(const char *ifname, const struct in6_addr *ifid, unsigned int options)
+int ra_init(const char *ifname, const struct in6_addr *ifid,
+               unsigned int options, unsigned int holdoff_interval)
 {
        ra_options = options;
+       ra_holdoff_interval = holdoff_interval;
 
        const pid_t ourpid = getpid();
        sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
@@ -357,7 +360,8 @@ bool ra_process(void)
 
                entry->valid = router_valid;
                entry->preferred = entry->valid;
-               changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry, 0, true);
+               changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry,
+                                               0, ra_holdoff_interval);
 
                // Parse hoplimit
                ra_conf_hoplimit(adv->nd_ra_curhoplimit);
@@ -387,7 +391,8 @@ bool ra_process(void)
                                        continue;
 
                                if (entry->priority > 0)
-                                       changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry, 0, true);
+                                       changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry,
+                                                                       0, ra_holdoff_interval);
                        } else if (opt->type == ND_OPT_PREFIX_INFORMATION && opt->len == 4) {
                                struct nd_opt_prefix_info *pinfo = (struct nd_opt_prefix_info*)opt;
                                entry->router = any;
@@ -404,7 +409,8 @@ bool ra_process(void)
                                        continue;
 
                                if (pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK)
-                                       changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry, 7200, true);
+                                       changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry,
+                                                                       7200, ra_holdoff_interval);
 
                                if (!(pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_AUTO) ||
                                                pinfo->nd_opt_pi_prefix_len != 64)
@@ -413,7 +419,8 @@ bool ra_process(void)
                                entry->target.s6_addr32[2] = lladdr.s6_addr32[2];
                                entry->target.s6_addr32[3] = lladdr.s6_addr32[3];
 
-                               changed |= odhcp6c_update_entry(STATE_RA_PREFIX, entry, 7200, true);
+                               changed |= odhcp6c_update_entry(STATE_RA_PREFIX, entry,
+                                                               7200, ra_holdoff_interval);
                        } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 2) {
                                entry->router = from.sin6_addr;
                                entry->priority = 0;
@@ -425,7 +432,8 @@ bool ra_process(void)
                                for (ssize_t i = 0; i < (opt->len - 1) / 2; ++i) {
                                        memcpy(&entry->target, &opt->data[6 + i * sizeof(entry->target)],
                                                        sizeof(entry->target));
-                                       changed |= odhcp6c_update_entry(STATE_RA_DNS, entry, 0, true);
+                                       changed |= odhcp6c_update_entry(STATE_RA_DNS, entry,
+                                                                       0, ra_holdoff_interval);
                                }
                        } else if (opt->type == ND_OPT_DNSSL && opt->len > 1) {
                                uint32_t *valid = (uint32_t*)&opt->data[2];
@@ -446,7 +454,8 @@ bool ra_process(void)
                                        if (entry->auxlen == 0)
                                                continue;
 
-                                       changed |= odhcp6c_update_entry(STATE_RA_SEARCH, entry, 0, true);
+                                       changed |= odhcp6c_update_entry(STATE_RA_SEARCH, entry,
+                                                                       0, ra_holdoff_interval);
                                        entry->auxlen = 0;
                                }
                        }

diff --git a/src/ra.h b/src/ra.h
index 3634f3cb4e1f45d8c6699914ad20c6767fb85d5e..c95c0194f3d65e86abe296b41cb4d0c873b86ae2 100644 (file)
--- a/src/ra.h
+++ b/src/ra.h
@@ -34,6 +34,7 @@ struct icmpv6_opt {
        (void*)(opt + opt->len) <= (void*)(end); opt += opt->len)
 
 
-int ra_init(const char *ifname, const struct in6_addr *ifid, unsigned int options);
+int ra_init(const char *ifname, const struct in6_addr *ifid,
+               unsigned int options, unsigned int holdoff_interval);
 bool ra_link_up(void);
 bool ra_process(void);