Re: Multicast from hell

[oogali () INTRANOVA NET (Omachonu Ogali)]

That code will only work if the receiving host has no daemon listening on
that port, you're better off with Alfred's patch.
http://www.freebsd.org/~alred/tcp_fix.diff
(I think)

Omachonu Ogali
Intranova Networking Group

On Thu, 27 Jan 2000, John Watkins wrote:

>  Here is a patch for FreeBSD
>
> --- tcp_input.c.orig    Tue Apr 20 15:09:15 1999
> +++ tcp_input.c Fri Jan 21 21:53:00 2000
> @@ -398,12 +398,36 @@
>                             "Connection attempt to TCP %s:%d from
> %s:%d\n",
>                             buf, ntohs(ti->ti_dport),
> inet_ntoa(ti->ti_src),
>                             ntohs(ti->ti_sport));
> -               }
> +               } else if (tiflags & TH_ACK) {
> +                       /*
> +                        * Alpha code in response to stream.c
> +                        * - Omachonu Ogali
> +                        */
> +                       char buf[4*sizeof "123"];
> +
> +#ifdef ICMP_BANDLIM
> +                       if (badport_bandlim(1) < 0)
> +                               goto drop;
> +#endif
> +
> +                       strcpy(buf, inet_ntoa(ti->ti_dst));
> +                       log(LOG_INFO,
> +                           "received TCP/ACK to non existant
> connection: %s:%d -> %s:%d\n",
> +                           inet_ntoa(ti->ti_src), ntohs(ti->ti_sport),
> buf,
> ntohs(ti->ti_dport));
> +
> +                       /*
> +                        * Drop without reset to prevent smurf-like tcp
> +                        * attack
> +                        */
> +
> +                       goto drop;
> +               } else {
>  #ifdef ICMP_BANDLIM
>                 if (badport_bandlim(1) < 0)
>                         goto drop;
>  #endif
>                 goto dropwithreset;
> +               }
>         }
>         tp = intotcpcb(inp);
>         if (tp == 0)