e4676ba603
these are quite extensive additions to the ipfw code. they include a change to the API because the old method was broken, but the user view is kept the same. The new code allows a particular match to skip forward to a particular line number, so that blocks of rules can be used without checking all the intervening rules. There are also many more ways of rejecting connections especially TCP related, and many many more ... see the man page for a complete description.
365 lines
9.5 KiB
C
365 lines
9.5 KiB
C
/*
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: ip_divert.c,v 1.11 1997/06/01 15:58:44 peter Exp $
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*/
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/protosw.h>
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#include <sys/socketvar.h>
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#include <sys/errno.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/in_pcb.h>
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#include <netinet/in_var.h>
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#include <netinet/ip_var.h>
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/*
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* Divert sockets
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*/
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/*
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* Allocate enough space to hold a full IP packet
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*/
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#define DIVSNDQ (65536 + 100)
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#define DIVRCVQ (65536 + 100)
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/* Global variables */
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/*
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* ip_input() and ip_output() set this secret value before calling us to
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* let us know which divert port to divert a packet to; this is done so
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* we can use the existing prototype for struct protosw's pr_input().
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* This is stored in host order.
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*/
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u_short ip_divert_port;
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/*
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* We set this value to a non-zero port number when we want the call to
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* ip_fw_chk() in ip_input() or ip_output() to ignore ``divert <port>''
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* chain entries. This is stored in host order.
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*/
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u_short ip_divert_ignore;
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/* Internal variables */
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static struct inpcbhead divcb;
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static struct inpcbinfo divcbinfo;
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static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
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static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
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/* Optimization: have this preinitialized */
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static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET };
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/* Internal functions */
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static int div_output(struct socket *so,
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struct mbuf *m, struct mbuf *addr, struct mbuf *control);
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/*
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* Initialize divert connection block queue.
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*/
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void
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div_init(void)
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{
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LIST_INIT(&divcb);
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divcbinfo.listhead = &divcb;
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/*
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* XXX We don't use the hash list for divert IP, but it's easier
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* to allocate a one entry hash list than it is to check all
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* over the place for hashbase == NULL.
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*/
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divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
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}
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/*
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* Setup generic address and protocol structures
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* for div_input routine, then pass them along with
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* mbuf chain. ip->ip_len is assumed to have had
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* the header length (hlen) subtracted out already.
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* We tell whether the packet was incoming or outgoing
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* by seeing if hlen == 0, which is a hack.
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*/
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void
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div_input(struct mbuf *m, int hlen)
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{
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struct ip *ip;
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struct inpcb *inp;
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struct socket *sa;
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/* Sanity check */
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if (ip_divert_port == 0)
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panic("div_input: port is 0");
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/* Assure header */
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if (m->m_len < sizeof(struct ip) &&
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(m = m_pullup(m, sizeof(struct ip))) == 0) {
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return;
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}
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ip = mtod(m, struct ip *);
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/* Record divert port */
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divsrc.sin_port = htons(ip_divert_port);
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/* Restore packet header fields */
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ip->ip_len += hlen;
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HTONS(ip->ip_len);
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HTONS(ip->ip_off);
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/* Record receive interface address, if any */
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divsrc.sin_addr.s_addr = 0;
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if (hlen) {
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struct ifaddr *ifa;
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#ifdef DIAGNOSTIC
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/* Sanity check */
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if (!(m->m_flags & M_PKTHDR))
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panic("div_input: no pkt hdr");
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#endif
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/* More fields affected by ip_input() */
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HTONS(ip->ip_id);
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/* Find IP address for recieve interface */
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for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first;
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ifa != NULL; ifa = ifa->ifa_link.tqe_next) {
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if (ifa->ifa_addr == NULL)
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continue;
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if (ifa->ifa_addr->sa_family != AF_INET)
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continue;
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divsrc.sin_addr =
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((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
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break;
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}
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}
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/* Put packet on socket queue, if any */
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sa = NULL;
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for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
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if (inp->inp_lport == htons(ip_divert_port))
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sa = inp->inp_socket;
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}
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if (sa) {
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if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc,
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m, (struct mbuf *)0) == 0)
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m_freem(m);
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else
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sorwakeup(sa);
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} else {
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m_freem(m);
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ipstat.ips_noproto++;
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ipstat.ips_delivered--;
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}
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}
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/*
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* Deliver packet back into the IP processing machinery.
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*
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* If no address specified, or address is 0.0.0.0, send to ip_output();
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* otherwise, send to ip_input() and mark as having been received on
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* the interface with that address.
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*
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* If no address specified, or dest port is 0, allow packet to divert
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* back to this socket; otherwise, don't.
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*/
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static int
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div_output(so, m, addr, control)
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struct socket *so;
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register struct mbuf *m;
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struct mbuf *addr, *control;
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{
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register struct inpcb *const inp = sotoinpcb(so);
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register struct ip *const ip = mtod(m, struct ip *);
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struct sockaddr_in *sin = NULL;
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int error = 0;
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if (control)
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m_freem(control); /* XXX */
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if (addr)
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sin = mtod(addr, struct sockaddr_in *);
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/* Loopback avoidance option */
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ip_divert_ignore = ntohs(inp->inp_lport);
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/* Reinject packet into the system as incoming or outgoing */
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if (!sin || sin->sin_addr.s_addr == 0) {
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/* Don't allow both user specified and setsockopt options,
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and don't allow packet length sizes that will crash */
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if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
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((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
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error = EINVAL;
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goto cantsend;
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}
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/* Convert fields to host order for ip_output() */
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NTOHS(ip->ip_len);
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NTOHS(ip->ip_off);
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/* Send packet to output processing */
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ipstat.ips_rawout++; /* XXX */
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error = ip_output(m, inp->inp_options, &inp->inp_route,
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(so->so_options & SO_DONTROUTE) |
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IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions);
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} else {
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struct ifaddr *ifa;
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/* Find receive interface with the given IP address */
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sin->sin_port = 0;
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if ((ifa = ifa_ifwithaddr((struct sockaddr *) sin)) == 0) {
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error = EADDRNOTAVAIL;
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goto cantsend;
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}
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m->m_pkthdr.rcvif = ifa->ifa_ifp;
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/* Send packet to input processing */
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ip_input(m);
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}
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/* Reset for next time (and other packets) */
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ip_divert_ignore = 0;
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return error;
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cantsend:
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ip_divert_ignore = 0;
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m_freem(m);
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return error;
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}
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static int
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div_attach(struct socket *so, int proto, struct proc *p)
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{
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struct inpcb *inp;
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int error;
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inp = sotoinpcb(so);
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if (inp)
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panic("div_attach");
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if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0)
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return error;
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if ((error = soreserve(so, div_sendspace, div_recvspace)) ||
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(error = in_pcballoc(so, &divcbinfo, p)))
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return error;
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inp = (struct inpcb *)so->so_pcb;
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inp->inp_ip_p = proto;
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inp->inp_flags |= INP_HDRINCL;
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/* The socket is always "connected" because
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we always know "where" to send the packet */
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so->so_state |= SS_ISCONNECTED;
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return 0;
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}
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static int
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div_detach(struct socket *so)
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{
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struct inpcb *inp;
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inp = sotoinpcb(so);
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if (inp == 0)
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panic("div_detach");
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in_pcbdetach(inp);
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return 0;
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}
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static int
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div_abort(struct socket *so)
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{
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soisdisconnected(so);
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return div_detach(so);
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}
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static int
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div_disconnect(struct socket *so)
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{
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if ((so->so_state & SS_ISCONNECTED) == 0)
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return ENOTCONN;
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return div_abort(so);
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}
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static int
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div_bind(struct socket *so, struct mbuf *nam, struct proc *p)
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{
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struct inpcb *inp;
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int s;
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int error;
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s = splnet();
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inp = sotoinpcb(so);
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error = in_pcbbind(inp, nam, p);
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splx(s);
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return 0;
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}
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static int
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div_shutdown(struct socket *so)
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{
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socantsendmore(so);
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return 0;
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}
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static int
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div_send(struct socket *so, int flags, struct mbuf *m, struct mbuf *nam,
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struct mbuf *control, struct proc *p)
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{
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/* Packet must have a header (but that's about it) */
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if (m->m_len < sizeof (struct ip) ||
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(m = m_pullup(m, sizeof (struct ip))) == 0) {
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ipstat.ips_toosmall++;
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m_freem(m);
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return EINVAL;
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}
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/* Send packet */
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return div_output(so, m, nam, control);
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}
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struct pr_usrreqs div_usrreqs = {
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div_abort, pru_accept_notsupp, div_attach, div_bind,
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pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach,
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div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp,
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pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown,
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in_setsockaddr, sosend, soreceive, soselect
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};
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