Date: Thu, 20 Dec 2001 15:07:50 -0800 (PST) From: Julian Elischer <julian@elischer.org> To: Henry Su <henrysu@nttmcl.com> Cc: freebsd-net@FreeBSD.ORG Subject: RE: socket call in the kernel Message-ID: <Pine.BSF.4.21.0112201503220.53471-100000@InterJet.elischer.org> In-Reply-To: <AJEHKCJLENGKGEHDIOJGOEMGCGAA.henrysu@nttmcl.com>
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I have two answers:
1/ Use ipfw add NNN fwd localhost,8001 [deny criteria]
to make the packet that is denied go to a default server listenning on
port 8001
2/ there is an in-kernel webserver built using netgraph but it's not
public, but you can definitly use the 'ksocket' node to open 'in kernel'
sockets and pass the result to an arbitrary node.
1 can do what you want with no kernel programming..
check it out..
man ipfw
On Thu, 20 Dec 2001, Henry Su wrote:
> Thanks, Julian and Alfred.
>
> I am trying to redirect the denied http request to a default web site. So my
> idea is in the "ip_fw_chk" function of ip_fw.c, add following code, when it
> will drop the packet. But as you pointed out in earlier email, socket can
> not be used in this case. Do u have any other solutions? Thanks a lot.
>
>
>
> * Finally, drop the packet.
> */
>
>
> /* my code start debug */
> /* find if it's a http packet */
> dst_port_h = ntohs(dst_port);
> if(dst_port_h==80){
> log(LOG_INFO,"src_port:%u src_ip:%d dst_port:%d dst_ip:%u",
> ntohs(src_port), src_ip.s_addr, nt
> ohs(dst_port), dst_ip.s_addr);
> /*s = 1;*/
> s = socket(AF_INET, SOCK_STREAM, 0);
> if (s < 0) {
> log(LOG_INFO,"Redirect socket can not be created");
> }else{
> log(LOG_INFO,"Redirect socket is created");
> /*
> bzero(&sa, sizeof sa);
> sa.sin_family = AF_INET;
> sa.sin_port = src_port;
> sa.sin_addr.s_addr = src_ip.s_addr;
> if (connect(s, (struct sockaddr *)&sa, sizeof sa) <
> 0) {
> log(LOG_INFO,"connect %d failed",
> src_ip.s_addr);
> close(s);
> }else{
> log(LOG_INFO,"connect %d ok",
> src_ip.s_addr);
> close(s);
> }
> */
> /*
> while ((bytes = read(s, buffer, BUFSIZ)) > 0)
> write(1, buffer, bytes);
> */
> }
> }
> /* end debug */
> return(IP_FW_PORT_DENY_FLAG);
>
>
> -----Original Message-----
> From: Julian Elischer [mailto:julian@elischer.org]
> Sent: Thursday, December 20, 2001 12:59 PM
> To: Henry Su
> Cc: freebsd-net@FreeBSD.ORG
> Subject: Re: socket call in the kernel
>
>
>
>
> You cannot do a socket directly but you can indirectly
> tell me what you are trying to do and I can help..
>
>
>
> On Thu, 20 Dec 2001, Henry Su wrote:
>
> > I am trying to modify ip_fw.c in the /usr/src/sys/netinet, I tried to add
> a
> > socket call in the code, it can be compiled, but when it runs into the
> code,
> > it just crashed. It gave me the "Fatal trap error 12", Memory address is
> > wrong.
> >
> > Can any one tell me if socket call can be used in kernel level? If not,
> how
> > can I accomplish socket communication in the kernel level?
> >
> > Thanks.
> >
> > ------------------------------------------------
> >
> > Henry Su
> >
> > NTT Multimedia Communications Laboratories, Inc.
> >
> > 250 Cambridge Avenue Suite 300
> >
> > Palo Alto, CA 94306, USA (PST:UTC -8H)
> >
> > Tel: +1 650 833 3652
> >
> > Fax: +1 650 326 1878
> >
> > http://www.nttmcl.com/
> >
> >
> >
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-net" in the body of the message
> >
>
>
>
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