On 2021-12-01 10:21, Klemens Nanni wrote:
> On Fri, Nov 26, 2021 at 01:35:14PM +0100, Krzysztof Kanas wrote:
> > Hi. When remote side in sppp doesn't reply for to PPP IPCP IP-Address
> > sppp will try to negotiate remote IP in endless loop. Instead use
> > 10.64.64.1 + if_index as remote IP.
>
> Why add some arbitrary RFC 1918 IP if negotiation fails? That's not
> what users request or expect.
>
I agree that is unexpected but I couldn't find any info in RFC's what to
do if remote side don't reply. I am not familiar enough with PPP/SPP,
so I tried simples thing I could think of, which is to assign RFC 1918
IP address.
I don't know OpenBSD that much but upon looking in the source, maybe the
proper fix would be to add another parameter to ifconfig and use
SIOCSIFDSTADDR ? Or another IOCTL would be better as usage of this would
be to set ifr_dstaddr, but ifr_dstaddr when IPCP remote address
negotiation fails.
I would really like this to be fixed in a proper way so I don't have to
use custom kernel.
> > While at it maybe it's worth to add that SPP is in RFC 1332 ?
>
> sppp(4) STANDARDS mentions RFC 1332, if that's what you mean.
Oh, sorry it's mentioned there. I missed that somehow.
>
> > Krzysztof Kanas
> >
> > Index: share/man/man4/sppp.4
> > ===================================================================
> > RCS file: /home/cvs//src/share/man/man4/sppp.4,v
> > retrieving revision 1.26
> > diff -r1.26 sppp.4
> > 284,285c284,285
> > < Negotiation loop avoidance is not fully implemented.
> > < If the negotiation doesn't converge, this can cause an endless loop.
>
> Please send unified diffs, i.e. use `-u' with CVS diff(1).
Will do.
>
> > ---
> > > In case when remote IP can't be negotiation after 10 retries pick
> > > 10.64.64.1 + if_index.
> > Index: sys/net/if_sppp.h
> > ===================================================================
> > RCS file: /home/cvs//src/sys/net/if_sppp.h,v
> > retrieving revision 1.30
> > diff -r1.30 if_sppp.h
> > 148a149,150
> > > #define IPCP_HISADDR_COUNTER_MAX 10
> > > u_int8_t hisaddr_counter; /* number of ipcp req for peer addr */
> > Index: sys/net/if_spppsubr.c
> > ===================================================================
> > RCS file: /home/cvs//src/sys/net/if_spppsubr.c,v
> > retrieving revision 1.190
> > diff -r1.190 if_spppsubr.c
> > 2466,2468c2466,2469
> > < * XXX This can result in an endless req - nak loop if peer
> > < * doesn't want to send us his address. Q: What should we do
> > < * about it? XXX A: implement the max-failure counter.
> > ---
> > > * This can result in an endless req - nak loop if peer
> > > * doesn't want to send us his address. Therefore we count
> > > * the number of request if it exceeds IPCP_HISADDR_COUNTER_MAX
> > > * assign remote address 10.64.64.1 + if_index.
> > 2471,2479c2472,2492
> > < buf[0] = IPCP_OPT_ADDRESS;
> > < buf[1] = 6;
> > < buf[2] = hisaddr >> 24;
> > < buf[3] = hisaddr >> 16;
> > < buf[4] = hisaddr >> 8;
> > < buf[5] = hisaddr;
> > < rlen = 6;
> > < if (debug)
> > < addlog("still need hisaddr ");
> > ---
> > > if (sp->ipcp.hisaddr_counter++ > IPCP_HISADDR_COUNTER_MAX) {
> > > sp->ipcp.hisaddr_counter = 0;
> > > desiredaddr = 10 << 24 | 64 << 16 | 64 << 8 | 1;
> > > desiredaddr += sp->pp_if.if_index;
> > > hisaddr = desiredaddr;
> > > sp->ipcp.req_hisaddr = desiredaddr;
> > > sp->ipcp.flags |= IPCP_HISADDR_SEEN;
> > > if (debug)
> > > addlog("%s guess ",
> > > sppp_dotted_quad(desiredaddr));
> > > } else {
> > > buf[0] = IPCP_OPT_ADDRESS;
> > > buf[1] = 6;
> > > buf[2] = hisaddr >> 24;
> > > buf[3] = hisaddr >> 16;
> > > buf[4] = hisaddr >> 8;
> > > buf[5] = hisaddr;
> > > rlen = 6;
> > > if (debug)
> > > addlog("still need hisaddr ");
> > > }
> >
