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/*
* interface.c -- implements fetchmail 'interface' and 'monitor' commands
*
* This module was implemented by George M. Sipe <gsipe@mindspring.com>
* or <gsipe@acm.org> and is:
*
* Copyright (c) 1996 by George M. Sipe - ALL RIGHTS RESERVED
*
* This is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2, or (at your option) any later version.
*/
#ifdef linux
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <linux/netdevice.h>
#include <errno.h>
#include "fetchmail.h"
static struct in_addr interface_address;
static struct in_addr interface_mask;
static int monitor_io = 0;
typedef struct {
struct in_addr addr, dstaddr, netmask;
int rx_packets, tx_packets;
} ifinfo_t;
/* Get active network interface information. Return non-zero upon success. */
static int _get_ifinfo_(int socket_fd, FILE *stats_file, const char *ifname,
ifinfo_t *ifinfo)
{
int namelen = strlen(ifname);
struct ifreq request;
char *cp, buffer[256];
/* initialize result */
memset((char *) ifinfo, 0, sizeof(ifinfo_t));
/* see if the interface is up */
strcpy(request.ifr_name, ifname);
errno = 0;
if (ioctl(socket_fd, SIOCGIFFLAGS, &request) < 0)
error(PS_IOERR, errno, "interface status check failed");
if (!(request.ifr_flags & IFF_RUNNING))
return(FALSE);
/* get the IP address */
strcpy(request.ifr_name, ifname);
if (ioctl(socket_fd, SIOCGIFADDR, &request) < 0)
return(FALSE);
ifinfo->addr = ((struct sockaddr_in *) (&request.ifr_addr))->sin_addr;
/* get the PPP destination IP address */
strcpy(request.ifr_name, ifname);
if (ioctl(socket_fd, SIOCGIFDSTADDR, &request) >= 0)
ifinfo->dstaddr = ((struct sockaddr_in *)
(&request.ifr_dstaddr))->sin_addr;
/* get the netmask */
strcpy(request.ifr_name, ifname);
if (ioctl(socket_fd, SIOCGIFNETMASK, &request) >= 0)
ifinfo->netmask = ((struct sockaddr_in *)
(&request.ifr_netmask))->sin_addr;
/* get the packet I/O counts */
while (fgets(buffer, sizeof(buffer) - 1, stats_file)) {
for (cp = buffer; *cp && *cp == ' '; ++cp);
if (!strncmp(cp, ifname, namelen) &&
cp[namelen] == ':') {
cp += namelen + 1;
sscanf(cp, "%d %*d %*d %*d %*d %d %*d %*d %*d %*d %*d",
&ifinfo->rx_packets, &ifinfo->tx_packets);
return(TRUE);
}
}
return(FALSE);
}
static int get_ifinfo(const char *ifname, ifinfo_t *ifinfo)
{
int socket_fd = socket(AF_INET, SOCK_DGRAM, 0);
FILE *stats_file = fopen("/proc/net/dev", "r");
int result;
if (socket_fd < 0 || !stats_file)
result = -1;
else
result = _get_ifinfo_(socket_fd, stats_file, ifname, ifinfo);
if (socket_fd >= 0)
close(socket_fd);
if (stats_file)
fclose(stats_file);
return(result);
}
/* Parse 'interface' specification. */
void interface_parse(void)
{
char *cp1, *cp2;
/* in the event we point to a null string, make pointer null */
if (interface && !*interface)
interface = NULL;
if (monitor && !*monitor)
monitor = NULL;
/* if no interface specification present, all done */
if (!interface)
return;
/* find and isolate just the IP address */
if (!(cp1 = strchr(interface, '/')))
(void) error(PS_SYNTAX, 0, "missing IP interface address");
*cp1++ = '\000';
/* find and isolate just the netmask */
if (!(cp2 = strchr(cp1, '/')))
cp2 = "255.255.255.255";
else
*cp2++ = '\000';
/* convert IP address and netmask */
if (!inet_aton(cp1, &interface_address))
(void) error(PS_SYNTAX, 0, "invalid IP interface address");
if (!inet_aton(cp2, &interface_mask))
(void) error(PS_SYNTAX, 0, "invalid IP interface mask");
/* apply the mask now to the IP address (range) required */
interface_address.s_addr &= interface_mask.s_addr;
return;
}
/* Save interface I/O counts. */
void interface_note_activity(void)
{
ifinfo_t ifinfo;
/* get the current I/O stats for the monitored link */
if (monitor && get_ifinfo(monitor, &ifinfo))
monitor_io = ifinfo.rx_packets + ifinfo.tx_packets;
}
/* Return TRUE if OK to poll, FALSE otherwise. */
int interface_approve(void)
{
ifinfo_t ifinfo;
/* check interface IP address (range), if specified */
if (interface) {
/* get interface info */
if (!get_ifinfo(interface, &ifinfo)) {
(void) error(0, 0, "skipping poll, %s down",
interface);
return(FALSE);
}
/* check the IP address (range) */
if ((ifinfo.addr.s_addr & interface_mask.s_addr) !=
interface_address.s_addr) {
(void) error(0, 0,
"skipping poll, %s IP address excluded",
interface);
return(FALSE);
}
}
/* if monitoring, check link for activity if it is up */
if (monitor && get_ifinfo(monitor, &ifinfo) &&
monitor_io == ifinfo.rx_packets + ifinfo.tx_packets) {
(void) error(0, 0, "skipping poll, %s inactive", monitor);
return(FALSE);
}
return(TRUE);
}
#endif /* linux */
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