433 lines
12 KiB
C
433 lines
12 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 1.31 1998/06/12 02:48:47 julian Exp $
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*/
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#include "opt_inet.h"
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#include "opt_ipfw.h"
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#include "opt_ipdivert.h"
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#ifndef INET
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#error "IPDIVERT requires INET."
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#endif
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#include <sys/param.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/systm.h>
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#include <sys/proc.h>
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#include <vm/vm_zone.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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* A 16 bit cookie is passed to the user process.
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* The user process can send it back to help the caller know something
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* about where the packet came from.
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*
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* If IPFW is the caller then the cookie is the rule that sent
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* us here. On reinjection is is the rule after which processing
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* should continue. Leaving it the same will make processing start
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* at the rule number after that which sent it here. Setting it to
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* 0 will restart processing at the beginning.
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*/
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u_int16_t ip_divert_cookie;
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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 sockaddr *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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divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
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divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb),
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maxsockets, ZONE_INTERRUPT, 0);
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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 = ip_divert_cookie;
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ip_divert_cookie = 0;
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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 receive 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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if (m->m_pkthdr.rcvif) {
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char name[32];
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/*
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* Hide the actual interface name in there in the
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* sin_zero array. XXX This needs to be moved to a
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* different sockaddr type for divert, e.g.
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* sockaddr_div with multiple fields like
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* sockaddr_dl. Presently we have only 7 bytes
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* but that will do for now as most interfaces
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* are 4 or less + 2 or less bytes for unit.
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* There is probably a faster way of doing this,
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* possibly taking it from the sockaddr_dl on the iface.
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* This solves the problem of a P2P link and a LAN interface
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* having the same address, which can result in the wrong
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* interface being assigned to the packet when fed back
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* into the divert socket. Theoretically if the daemon saves
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* and re-uses the sockaddr_in as suggested in the man pages,
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* this iface name will come along for the ride.
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* (see div_output for the other half of this.)
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*/
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sprintf(name, "%s%d",
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m->m_pkthdr.rcvif->if_name, m->m_pkthdr.rcvif->if_unit);
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strncpy(divsrc.sin_zero, name, 7);
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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 sockaddr *addr;
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struct mbuf *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 = (struct sockaddr_in *)addr;
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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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/* Loopback avoidance and state recovery */
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if (sin) {
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int len = 0;
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char *c = sin->sin_zero;
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ip_divert_cookie = sin->sin_port;
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/*
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* Find receive interface with the given name or IP address.
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* The name is user supplied data so don't trust it's size or
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* that it is zero terminated. The name has priority.
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* We are presently assuming that the sockaddr_in
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* has not been replaced by a sockaddr_div, so we limit it
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* to 16 bytes in total. the name is stuffed (if it exists)
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* in the sin_zero[] field.
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*/
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while (*c++ && (len++ < sizeof(sin->sin_zero)));
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if ((len > 0) && (len < sizeof(sin->sin_zero)))
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m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
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} else {
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ip_divert_cookie = 0;
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}
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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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/*
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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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*/
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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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/* If no luck with the name above. check by IP address. */
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if (m->m_pkthdr.rcvif == NULL) {
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if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) {
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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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}
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/* Send packet to input processing */
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ip_input(m);
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}
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/* paranoid: Reset for next time (and other packets) */
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/* almost definitly already done in the ipfw filter but.. */
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ip_divert_cookie = 0;
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return error;
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cantsend:
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ip_divert_cookie = 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, s;
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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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s = splnet();
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error = in_pcballoc(so, &divcbinfo, p);
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splx(s);
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if (error)
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return error;
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error = soreserve(so, div_sendspace, div_recvspace);
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if (error)
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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 sockaddr *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 sockaddr *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, sopoll
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};
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