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DHCP Server Daemon
This commit is contained in:
Ted Lemon
208
socket.c
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208
socket.c
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/* socket.c
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BSD socket interface code... */
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/*
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* Copyright (c) 1995 The Internet Software Consortium. 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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*
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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. Neither the name of The Internet Software Consortium nor the names
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* of its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
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* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* 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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* This software has been written for the Internet Software Consortium
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* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
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* Enterprises. To learn more about the Internet Software Consortium,
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* see ``http://www.vix.com/isc''. To learn more about Vixie
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* Enterprises, see ``http://www.vix.com''.
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*/
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#ifndef lint
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static char copyright[] =
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"@(#) Copyright (c) 1995 The Internet Software Consortium. All rights reserved.\n";
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#endif /* not lint */
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#include "dhcpd.h"
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#include <sys/ioctl.h>
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/* List of sockets we're accepting packets on... */
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struct socklist {
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struct socklist *next;
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struct sockaddr_in addr;
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int sock;
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} *sockets;
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/* Return the list of IP addresses associated with each network interface. */
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u_int32_t *get_interface_list (count)
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int *count;
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{
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u_int32_t *intbuf = (u_int32_t *)0;
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static char buf [8192];
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struct ifconf ic;
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int i;
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int sock;
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int ifcount = 0;
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int ifix = 0;
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/* Create an unbound datagram socket to do the SIOCGIFADDR ioctl on. */
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if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
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error ("Can't create addrlist socket");
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/* Get the interface configuration information... */
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ic.ifc_len = sizeof buf;
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ic.ifc_ifcu.ifcu_buf = (caddr_t)buf;
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i = ioctl(sock, SIOCGIFCONF, &ic);
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close (sock);
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if (i < 0)
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error ("ioctl: SIOCGIFCONF: %m");
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again:
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/* Cycle through the list of interfaces looking for IP addresses.
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Go through twice; once to count the number if addresses, and a
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second time to copy them into an array of addresses. */
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for (i = 0; i < ic.ifc_len;) {
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struct ifreq *ifp = (struct ifreq *)((caddr_t)ic.ifc_req + i);
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i += (sizeof ifp -> ifr_name) + ifp -> ifr_addr.sa_len;
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if (ifp -> ifr_addr.sa_family == AF_INET) {
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struct sockaddr_in *foo =
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(struct sockaddr_in *)(&ifp -> ifr_addr);
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/* We don't want the loopback interface. */
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if (foo -> sin_addr.s_addr == INADDR_LOOPBACK)
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continue;
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if (intbuf)
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intbuf [ifix++] = foo -> sin_addr.s_addr;
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else
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++ifcount;
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}
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}
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/* If we haven't already filled our array, allocate it and go
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again. */
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if (!intbuf) {
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intbuf = (u_int32_t *)dmalloc ((ifcount + 1)
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* sizeof (u_int32_t),
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"get_interface_list");
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if (!intbuf)
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return intbuf;
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goto again;
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}
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*count = ifcount;
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return intbuf;
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}
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void listen_on (port, address)
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u_int16_t port;
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u_int32_t address;
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{
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struct sockaddr_in name;
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int sock;
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struct socklist *tmp;
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int flag;
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name.sin_family = AF_INET;
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name.sin_port = port;
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name.sin_addr.s_addr = address;
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memset (name.sin_zero, 0, sizeof (name.sin_zero));
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/* List addresses on which we're listening. */
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note ("Receiving on %s, port %d",
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inet_ntoa (name.sin_addr), htons (name.sin_port));
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if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
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error ("Can't create dhcp socket: %m");
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flag = 1;
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if (setsockopt (sock, SOL_SOCKET, SO_REUSEADDR,
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&flag, sizeof flag) < 0)
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error ("Can't set SO_REUSEADDR option on dhcp socket: %m");
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if (setsockopt (sock, SOL_SOCKET, SO_BROADCAST,
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&flag, sizeof flag) < 0)
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error ("Can't set SO_BROADCAST option on dhcp socket: %m");
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if (bind (sock, (struct sockaddr *)&name, sizeof name) < 0)
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error ("Can't bind to dhcp address: %m");
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tmp = (struct socklist *)dmalloc (sizeof (struct socklist),
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"listen_on");
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if (!tmp)
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error ("Can't allocate memory for socket list.");
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tmp -> addr = name;
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tmp -> sock = sock;
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tmp -> next = sockets;
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sockets = tmp;
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}
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unsigned char packbuf [65536]; /* Should cover the gnarliest MTU... */
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void dispatch ()
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{
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struct sockaddr_in from;
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int fromlen = sizeof from;
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fd_set r, w, x;
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struct socklist *l;
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int max = 0;
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int count;
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int result;
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FD_ZERO (&r);
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FD_ZERO (&w);
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FD_ZERO (&x);
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do {
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/* Set up the read mask. */
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for (l = sockets; l; l = l -> next) {
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FD_SET (l -> sock, &r);
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FD_SET (l -> sock, &x);
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if (l -> sock > max)
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max = l -> sock;
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}
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/* Wait for a packet or a timeout... XXX */
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count = select (max + 1, &r, &w, &x, (struct timeval *)0);
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/* Not likely to be transitory... */
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if (count < 0)
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error ("select: %m");
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for (l = sockets; l; l = l -> next) {
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if (!FD_ISSET (l -> sock, &r))
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continue;
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if ((result =
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recvfrom (l -> sock, packbuf, sizeof packbuf, 0,
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(struct sockaddr *)&from, &fromlen))
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< 0) {
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warn ("recvfrom failed on %s: %m",
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inet_ntoa (l -> addr.sin_addr));
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sleep (5);
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continue;
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}
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note ("request from %s, port %d",
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inet_ntoa (from.sin_addr),
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htons (from.sin_port));
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do_packet (packbuf, result, &from, fromlen, l -> sock);
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}
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} while (1);
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}
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