Re: rtalloc()/rtfree() problems on CURRENT

From: Gleb Smirnoff (glebius_at_cell.sick.ru)
Date: 02/24/04

  • Next message: Vasenin Alexander aka BlackSir: "RE: ng_netflow: testers are welcome" 
    Date: Tue, 24 Feb 2004 13:21:13 +0300
To: Andre Oppermann <andre@freebsd.org>

      Dear Andre,

      first, thanks for your feedback.

    On Tue, Feb 24, 2004 at 11:14:59AM +0100, Andre Oppermann wrote:
    A> Most of the time, if you don't need a cloned route allocated, you can
    A> just use rtalloc_ign(&ro, RTF_CLONING) to just get a reference to the
    A> existing rtentry. Not allocating a new cloned route saves work and
    A> time for the rtalloc code.

    Thanks for this hint. So if using rtalloc_ign() I do not need to call rtfree()?
    Why does this situation is not clear in manpage? :)

    A> > if (ro.ro_rt != NULL) {
    A> > struct rtentry *rt = ro.ro_rt;
    A> >
    A> > /* here some read-only things are done with rt */
    A>
    A> Maybe you do some nasty things to rt here?

    Really, I don't :) Exact code is given at end of the mail.

    A> > rtfree(ro.ro_rt);
    A> > }
    A> >
    A> > But on CURRENT rtfree() causes panic. Here is backtrace:
    A> ...
    A> > Does this mean that something is broken in CURRENT or I am doing something wrong?
    A>
    A> rtalloc() and rtfree() are used quite often in the network code and
    A> otherwise work fine. The odds are high that you are doing something
    A> wrong.

    Here is exact code:

            bzero((caddr_t)&ro, sizeof(ro));
            sin = (struct sockaddr_in *)&ro.ro_dst;
            sin->sin_len = sizeof(*sin);
            sin->sin_family = AF_INET;
            sin->sin_addr = fle->r.r_dst;
            rtalloc(&ro);
            if (ro.ro_rt != NULL) {
                    struct rtentry *rt = ro.ro_rt;
     
                    /* This is cloned route, use its parent */
                    if (ro.ro_rt->rt_flags & RTF_WASCLONED &&
                        ro.ro_rt->rt_parent)
                            rt = ro.ro_rt->rt_parent;
     
                    fle->o_ifx = rt->rt_ifp->if_index;
     
                    if (rt->rt_flags & RTF_GATEWAY &&
                        rt->rt_gateway->sa_family == AF_INET)
                            fle->next_hop =
                                ((struct sockaddr_in *)(rt->rt_gateway))->sin_addr;
     
                    if (rt_mask(rt))
                            fle->dst_mask =
                                bit_count(((struct sockaddr_in *)rt_mask(rt))->sin_addr.s_a
    ddr);
                    else if (rt->rt_flags & RTF_HOST)
                            /* Give up. We can't determine mask :( */
                            fle->dst_mask = 32;
     
                    rtfree(ro.ro_rt);
            } 

    -- 
Totus tuus, Glebius.
GLEBIUS-RIPN GLEB-RIPE
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    • Re: rtalloc()/rtfree() problems on CURRENT
      ... if you give me some pointers where to look at. ... A> Most of the time, if you don't need a cloned route allocated, you can ... A> time for the rtalloc code. ... A>> But on CURRENT rtfree() causes panic. ...
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      ... > Dear sirs, ... Most of the time, if you don't need a cloned route allocated, you can ... time for the rtalloc code. ... > But on CURRENT rtfree() causes panic. ...
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    • Re: rtalloc()/rtfree() problems on CURRENT
      ... A> You still have to call rtfree() to decrement the refcount of the rtentry. ... A>> A> Maybe you do some nasty things to rt here? ... I don't:) Exact code is given at end of the mail. ...
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