<div dir="ltr"><div dir="ltr"><div>>why is this not the case in your setup ?</div><div>Because sometimes odhcp6c miss restart, probably because of Bridge Mode (it's attached to bridge interface).</div><div>Anyway, I use a hotplug script which sends SIGUSR2 signal to odhcp6c on link-up event.</div><div>Of course I could send SIGTERM, but I think it's not the proper way to solve problem.</div><div><br></div><div>I thought that it is an obvious bug because I see a lack of consistency.</div><div>Why odhcp6c on SIGUSR2 </div><div>clear STATE_IA_ and resend DHCPV6_MSG_</div><div>and don't do same with RA - clear STATE_RA_ and resend Router Solicitation message?<br><br>Br,<br>Pavel</div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 19 Mar 2019 at 12:36, Hans Dedecker <<a href="mailto:dedeckeh@gmail.com">dedeckeh@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
On Mon, Mar 18, 2019 at 8:51 PM Pavel Merzlyakov<br>
<<a href="mailto:pavel.merzlyakov@gmail.com" target="_blank">pavel.merzlyakov@gmail.com</a>> wrote:<br>
><br>
> Hi,<br>
><br>
> >Can you be elaborate more in detail what use case you want to cover<br>
> >with this patch; in other words what is not working now ?<br>
> Ok,<br>
> my setup:<br>
> Two peer routers A and B which both connected to gateway C.<br>
> Routers A and B have public IPv6 addresses on WAN interfaces from same subnet (because of RA on C) and private IPv6 addresses on LAN interfaces.<br>
> and issue:<br>
> If I unplug router B from C and then plug it in LAN port of router A:<br>
> 1) Router B does not send Router Solicitation message. So router B does not have a valid gateway for some time.<br>
Since we've linksensing support in netifd the wan/wan6 interface<br>
should be brought down when the cable is unplugged; the wan/wan6<br>
interface will be brought up again when the cable is plugged in. This<br>
means odhcp6c will be restarted and will start sending RS; why is this<br>
not the case in your setup ?<br>
<br>
Hans<br>
> 2) Router B does not delete old IPv6 address on the WAN. After first Router Advertisement message router B is capable to send a request via new gateway A, but it can't receive responses because of invalid/old source address in request.<br>
><br>
><br>
> >Why do you want to restart RA if an SIGUSR2 signal is received ?<br>
> Because I assume that SIGUSR2 signal is equivalent to link-up event (see odhcp6c:674 -> <a href="https://git.openwrt.org/?p=project/odhcp6c.git;a=blob;f=src/odhcp6c.c;h=19a86f2654bf3c59b0f47cf0aedd87235187bf89;hb=d2e247d8d87ecf8c60fcf0acdad05667bd379521#l674" rel="noreferrer" target="_blank">https://git.openwrt.org/?p=project/odhcp6c.git;a=blob;f=src/odhcp6c.c;h=19a86f2654bf3c59b0f47cf0aedd87235187bf89;hb=d2e247d8d87ecf8c60fcf0acdad05667bd379521#l674</a>).<br>
> In my case I use hotplug script witch on link-up sends SIGUSR2 signal to odhcp6c (it's connected to bridge interface).<br>
> ra_restart () could be called without condition in beginning of the main loop.<br>
><br>
> Br,<br>
> Pavel<br>
><br>
> On Mon, 18 Mar 2019 at 18:26, Hans Dedecker <<a href="mailto:dedeckeh@gmail.com" target="_blank">dedeckeh@gmail.com</a>> wrote:<br>
>><br>
>> Hi,<br>
>><br>
>> On Mon, Mar 18, 2019 at 2:43 PM <<a href="mailto:pavel.merzlyakov@gmail.com" target="_blank">pavel.merzlyakov@gmail.com</a>> wrote:<br>
>> ><br>
>> > From: Pavel Merzlyakov <<a href="mailto:pavel.merzlyakov@gmail.com" target="_blank">pavel.merzlyakov@gmail.com</a>><br>
>> ><br>
>> > A subnet may be changed after link-up event<br>
>> Can you be elaborate more in detail what use case you want to cover<br>
>> with this patch; in other words what is not working now ?<br>
>> ><br>
>> > Signed-off-by: Pavel Merzlyakov <<a href="mailto:pavel.merzlyakov@gmail.com" target="_blank">pavel.merzlyakov@gmail.com</a>><br>
>> > ---<br>
>> > src/odhcp6c.c | 3 +++<br>
>> > src/ra.c | 20 +++++++++++++++++---<br>
>> > src/ra.h | 1 +<br>
>> > 3 files changed, 21 insertions(+), 3 deletions(-)<br>
>> ><br>
>> > diff --git a/src/odhcp6c.c b/src/odhcp6c.c<br>
>> > index 19a86f2..dd20f39 100644<br>
>> > --- a/src/odhcp6c.c<br>
>> > +++ b/src/odhcp6c.c<br>
>> > @@ -455,6 +455,9 @@ int main(_unused int argc, char* const argv[])<br>
>> ><br>
>> > syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);<br>
>> ><br>
>> > + if (signal_usr2)<br>
>> > + ra_restart();<br>
>> Why do you want to restart RA if an SIGUSR2 signal is received ?<br>
>><br>
>> Hans<br>
>> > +<br>
>> > signal_usr1 = signal_usr2 = false;<br>
>> > int mode = dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);<br>
>> > if (mode != DHCPV6_STATELESS)<br>
>> > diff --git a/src/ra.c b/src/ra.c<br>
>> > index 898f449..917df11 100644<br>
>> > --- a/src/ra.c<br>
>> > +++ b/src/ra.c<br>
>> > @@ -55,6 +55,7 @@ static int sock = -1, rtnl = -1;<br>
>> > static int if_index = 0;<br>
>> > static char if_name[IF_NAMESIZE] = {0};<br>
>> > static volatile int rs_attempt = 0;<br>
>> > +static const int rs_attempt_limit = 4;<br>
>> > static struct in6_addr lladdr = IN6ADDR_ANY_INIT;<br>
>> > static unsigned int ra_options = 0;<br>
>> > static unsigned int ra_holdoff_interval = 0;<br>
>> > @@ -179,6 +180,20 @@ failure:<br>
>> > return -1;<br>
>> > }<br>
>> ><br>
>> > +void ra_restart(void)<br>
>> > +{<br>
>> > + const int rs_attempt_old = rs_attempt;<br>
>> > +<br>
>> > + odhcp6c_clear_state(STATE_RA_PREFIX);<br>
>> > + odhcp6c_clear_state(STATE_RA_ROUTE);<br>
>> > + odhcp6c_clear_state(STATE_RA_DNS);<br>
>> > + odhcp6c_clear_state(STATE_RA_SEARCH);<br>
>> > +<br>
>> > + rs_attempt = 0;<br>
>> > + if (rs_attempt_old == 0 || rs_attempt_old >= rs_attempt_limit)<br>
>> > + ra_send_rs(SIGALRM);<br>
>> > +}<br>
>> > +<br>
>> > static void ra_send_rs(int signal __attribute__((unused)))<br>
>> > {<br>
>> > const struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};<br>
>> > @@ -193,7 +208,7 @@ static void ra_send_rs(int signal __attribute__((unused)))<br>
>> > if (sendto(sock, &rs, len, MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)<br>
>> > syslog(LOG_ERR, "Failed to send RS (%s)", strerror(errno));<br>
>> ><br>
>> > - if (++rs_attempt <= 3)<br>
>> > + if (++rs_attempt < rs_attempt_limit)<br>
>> > alarm(4);<br>
>> > }<br>
>> ><br>
>> > @@ -243,8 +258,7 @@ bool ra_link_up(void)<br>
>> > if (ret) {<br>
>> > syslog(LOG_NOTICE, "carrier => %i event on %s", (int)!nocarrier, if_name);<br>
>> ><br>
>> > - rs_attempt = 0;<br>
>> > - ra_send_rs(SIGALRM);<br>
>> > + ra_restart();<br>
>> > }<br>
>> ><br>
>> > return ret;<br>
>> > diff --git a/src/ra.h b/src/ra.h<br>
>> > index 9acc8cd..4ec208f 100644<br>
>> > --- a/src/ra.h<br>
>> > +++ b/src/ra.h<br>
>> > @@ -46,5 +46,6 @@ struct icmpv6_opt_route_info {<br>
>> ><br>
>> > int ra_init(const char *ifname, const struct in6_addr *ifid,<br>
>> > unsigned int options, unsigned int holdoff_interval);<br>
>> > +void ra_restart(void);<br>
>> > bool ra_link_up(void);<br>
>> > bool ra_process(void);<br>
>> > --<br>
>> > 2.21.0<br>
>> ><br>
>> ><br>
>> > _______________________________________________<br>
>> > openwrt-devel mailing list<br>
>> > <a href="mailto:openwrt-devel@lists.openwrt.org" target="_blank">openwrt-devel@lists.openwrt.org</a><br>
>> > <a href="https://lists.openwrt.org/mailman/listinfo/openwrt-devel" rel="noreferrer" target="_blank">https://lists.openwrt.org/mailman/listinfo/openwrt-devel</a><br>
</blockquote></div>