294 lines
9.3 KiB
C
294 lines
9.3 KiB
C
/* ifchange.c - functions to call the interface change daemon
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*
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* Copyright (c) 2004-2014 Nicholas J. Kain <njkain at gmail dot com>
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* 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 are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND 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 COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <string.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <arpa/inet.h>
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#include <sys/types.h>
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#include <errno.h>
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#include "options.h"
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#include "ndhc.h"
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#include "dhcp.h"
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#include "options.h"
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#include "arp.h"
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#include "log.h"
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#include "io.h"
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#include "strl.h"
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#include "ifchange.h"
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static struct dhcpmsg cfg_packet; // Copy of the current configuration packet.
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static int ifchd_cmd_u8(char *buf, size_t buflen, char *optname,
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uint8_t *optdata, ssize_t optlen)
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{
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if (!optdata || optlen < 1)
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return -1;
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return snprintf(buf, buflen, "%s:%c;", optname, *optdata);
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}
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static int ifchd_cmd_u16(char *buf, size_t buflen, char *optname,
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uint8_t *optdata, ssize_t optlen)
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{
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if (!optdata || optlen < 2)
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return -1;
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uint16_t v;
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memcpy(&v, optdata, 2);
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v = ntohs(v);
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return snprintf(buf, buflen, "%s:%hu;", optname, v);
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}
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static int ifchd_cmd_s32(char *buf, size_t buflen, char *optname,
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uint8_t *optdata, ssize_t optlen)
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{
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if (!optdata || optlen < 4)
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return -1;
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int32_t v;
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memcpy(&v, optdata, 4);
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v = ntohl(v);
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return snprintf(buf, buflen, "%s:%d;", optname, v);
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}
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static int ifchd_cmd_ip(char *buf, size_t buflen, char *optname,
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uint8_t *optdata, ssize_t optlen)
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{
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char ipbuf[INET_ADDRSTRLEN];
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if (!optdata || optlen < 4)
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return -1;
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inet_ntop(AF_INET, optdata, ipbuf, sizeof ipbuf);
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return snprintf(buf, buflen, "%s:%s;", optname, ipbuf);
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}
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static int ifchd_cmd_iplist(char *buf, size_t buflen, char *optname,
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uint8_t *optdata, ssize_t optlen)
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{
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char ipbuf[INET_ADDRSTRLEN];
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char *obuf = buf;
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if (!optdata || optlen < 4)
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return -1;
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inet_ntop(AF_INET, optdata, ipbuf, sizeof ipbuf);
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ssize_t wc = snprintf(buf, buflen, "%s:%s", optname, ipbuf);
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if (wc <= 0)
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return wc;
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optlen -= 4;
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optdata += 4;
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buf += wc;
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while (optlen >= 4) {
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inet_ntop(AF_INET, optdata, ipbuf, sizeof ipbuf);
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if (buflen < strlen(ipbuf) + (buf - obuf) + 2)
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break;
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buf += snprintf(buf, buflen - (buf - obuf), ",%s", ipbuf);
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optlen -= 4;
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optdata += 4;
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}
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buf += snprintf(buf, buflen - (buf - obuf), ";");
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return buf - obuf;
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}
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static int ifchd_cmd_bytes(char *buf, size_t buflen, char *optname,
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uint8_t *optdata, ssize_t optlen)
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{
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char *obuf = buf;
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if (buflen < strlen(optname) + optlen + 3)
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return -1;
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buf += snprintf(buf, buflen, "%s:", optname);
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memcpy(buf, optdata, optlen);
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buf[optlen] = ';';
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buf[optlen+1] = '\0';
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return (buf - obuf) + optlen + 1;
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}
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#define CMD_ROUTER "routr"
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#define CMD_IP4SET "ip4"
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#define CMD_DNS "dns"
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#define CMD_LPRSVR "lpr"
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#define CMD_NTPSVR "ntp"
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#define CMD_WINS "wins"
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#define CMD_HOSTNAME "host"
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#define CMD_DOMAIN "dom"
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#define CMD_TIMEZONE "tzone"
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#define CMD_MTU "mtu"
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#define CMD_IPTTL "ipttl"
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#define CMD_NULL "NULL"
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#define IFCHD_SW_CMD(x, y) case DCODE_##x: \
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optname = CMD_##x; \
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dofn = ifchd_cmd_##y; \
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break
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static int ifchd_cmd(char *buf, size_t buflen, uint8_t *optdata,
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ssize_t optlen, uint8_t code)
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{
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int (*dofn)(char *, size_t, char *, uint8_t *, ssize_t);
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char *optname;
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switch (code) {
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IFCHD_SW_CMD(ROUTER, ip);
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IFCHD_SW_CMD(DNS, iplist);
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IFCHD_SW_CMD(LPRSVR, iplist);
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IFCHD_SW_CMD(NTPSVR, iplist);
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IFCHD_SW_CMD(WINS, iplist);
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IFCHD_SW_CMD(HOSTNAME, bytes);
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IFCHD_SW_CMD(DOMAIN, bytes);
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IFCHD_SW_CMD(TIMEZONE, s32);
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IFCHD_SW_CMD(MTU, u16);
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IFCHD_SW_CMD(IPTTL, u8);
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default:
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log_line("Invalid option code (%c) for ifchd cmd.", code);
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return -1;
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}
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return dofn(buf, buflen, optname, optdata, optlen);
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}
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#undef IFCHD_SW_CMD
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static void pipewrite(struct client_state_t *cs, const char *buf, size_t count)
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{
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cs->ifchWorking = 1;
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if (safe_write(pToIfchW, buf, count) == -1) {
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log_error("pipewrite: write failed: %s", strerror(errno));
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return;
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}
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log_line("Sent to ifchd: %s", buf);
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}
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void ifchange_deconfig(struct client_state_t *cs)
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{
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char buf[256];
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if (cs->ifDeconfig)
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return;
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cs->ifDeconfig = 1;
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snprintf(buf, sizeof buf, "ip4:0.0.0.0,255.255.255.255;");
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log_line("Resetting %s IP configuration.", client_config.interface);
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pipewrite(cs, buf, strlen(buf));
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memset(&cfg_packet, 0, sizeof cfg_packet);
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}
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static size_t send_client_ip(char *out, size_t olen, struct dhcpmsg *packet)
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{
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uint8_t optdata[MAX_DOPT_SIZE], olddata[MAX_DOPT_SIZE];
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char ipb[4*INET_ADDRSTRLEN], ip[INET_ADDRSTRLEN], sn[INET_ADDRSTRLEN],
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bc[INET_ADDRSTRLEN];
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ssize_t optlen, oldlen;
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bool change_ipaddr = false;
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bool have_subnet = false;
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bool change_subnet = false;
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bool have_bcast = false;
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bool change_bcast = false;
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if (memcmp(&packet->yiaddr, &cfg_packet.yiaddr, sizeof packet->yiaddr))
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change_ipaddr = true;
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inet_ntop(AF_INET, &packet->yiaddr, ip, sizeof ip);
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optlen = get_dhcp_opt(packet, DCODE_SUBNET, optdata, sizeof optdata);
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if (optlen >= 4) {
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have_subnet = true;
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inet_ntop(AF_INET, optdata, sn, sizeof sn);
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oldlen = get_dhcp_opt(&cfg_packet, DCODE_SUBNET, olddata,
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sizeof olddata);
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if (oldlen != optlen || memcmp(optdata, olddata, optlen))
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change_subnet = true;
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}
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optlen = get_dhcp_opt(packet, DCODE_BROADCAST, optdata, sizeof optdata);
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if (optlen >= 4) {
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have_bcast = true;
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inet_ntop(AF_INET, optdata, bc, sizeof bc);
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oldlen = get_dhcp_opt(&cfg_packet, DCODE_BROADCAST, olddata,
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sizeof olddata);
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if (oldlen != optlen || memcmp(optdata, olddata, optlen))
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change_bcast = true;
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}
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// Nothing to change.
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if (!change_ipaddr && !change_subnet && !change_bcast)
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return 0;
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if (!have_subnet) {
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static char snClassC[] = "255.255.255.0";
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log_line("Server did not send a subnet mask. Assuming class C (255.255.255.0).");
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memcpy(sn, snClassC, sizeof snClassC);
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}
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if (have_bcast) {
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snprintf(ipb, sizeof ipb, "ip4:%s,%s,%s;", ip, sn, bc);
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} else {
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snprintf(ipb, sizeof ipb, "ip4:%s,%s;", ip, sn);
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}
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strnkcat(out, ipb, olen);
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return strlen(ipb);
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}
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static size_t send_cmd(char *out, size_t olen, struct dhcpmsg *packet,
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uint8_t code)
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{
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char buf[2048];
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uint8_t optdata[MAX_DOPT_SIZE], olddata[MAX_DOPT_SIZE];
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ssize_t optlen, oldlen;
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if (!packet)
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return 0;
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memset(buf, '\0', sizeof buf);
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optlen = get_dhcp_opt(packet, code, optdata, sizeof optdata);
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if (!optlen)
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return 0;
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oldlen = get_dhcp_opt(&cfg_packet, code, olddata, sizeof olddata);
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if (oldlen == optlen && !memcmp(optdata, olddata, optlen))
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return 0;
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if (ifchd_cmd(buf, sizeof buf, optdata, optlen, code) == -1)
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return 0;
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strnkcat(out, buf, olen);
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return strlen(buf);
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}
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void ifchange_bind(struct client_state_t *cs, struct dhcpmsg *packet)
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{
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char buf[2048];
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int tbs = 0;
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if (!packet)
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return;
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memset(buf, 0, sizeof buf);
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tbs |= send_client_ip(buf, sizeof buf, packet);
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tbs |= send_cmd(buf, sizeof buf, packet, DCODE_ROUTER);
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tbs |= send_cmd(buf, sizeof buf, packet, DCODE_DNS);
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tbs |= send_cmd(buf, sizeof buf, packet, DCODE_HOSTNAME);
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tbs |= send_cmd(buf, sizeof buf, packet, DCODE_DOMAIN);
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tbs |= send_cmd(buf, sizeof buf, packet, DCODE_MTU);
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tbs |= send_cmd(buf, sizeof buf, packet, DCODE_WINS);
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if (tbs)
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pipewrite(cs, buf, strlen(buf));
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cs->ifDeconfig = 0;
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memcpy(&cfg_packet, packet, sizeof cfg_packet);
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}
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