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Sourcecode: fetchmail version File versions

interface.c

/*
 * interface.c -- implements fetchmail 'interface' and 'monitor' commands
 *
 * This module was implemented by George M. Sipe <gsipe@pobox.com>
 * or <gsipe@acm.org> and is:
 *
 *    Copyright (c) 1996,1997 by George M. Sipe
 *
 *      FreeBSD specific portions written by and Copyright (c) 1999 
 *      Andy Doran <ad@psn.ie>.
 *
 * For license terms, see the file COPYING in this directory.
 */
#include <sys/types.h>
#include <sys/param.h>

#if (defined(linux) && !defined(INET6_ENABLE)) || defined(__FreeBSD__)

#include "config.h"
#include <stdio.h>
#include <string.h>
#if defined(STDC_HEADERS)
#include <stdlib.h>
#endif
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#if defined(__FreeBSD__)
#if defined __FreeBSD_USE_KVM
#if __FreeBSD_version >= 300001
#include <net/if_var.h>
#endif
#include <kvm.h>
#include <nlist.h>
#include <sys/fcntl.h>
#else
#include <sys/sysctl.h>
#include <net/route.h>
#include <net/if_dl.h>
#endif
#endif
#include "config.h"
#include "fetchmail.h"
#include "socket.h"
#include "i18n.h"
#include "tunable.h"

typedef struct {
      struct in_addr addr, dstaddr, netmask;
      int rx_packets, tx_packets;
} ifinfo_t;

struct interface_pair_s {
      struct in_addr interface_address;
      struct in_addr interface_mask;
} *interface_pair;

static char *netdevfmt;

/*
 * Count of packets to see on an interface before monitor considers it up.
 * Needed because when pppd shuts down the link, the packet counts go up
 * by two (one rx and one tx?, maybe).  A value of 2 seems to do the trick,
 * but we'll give it some extra.
 */
#define MONITOR_SLOP          5

#if defined(linux)

void interface_init(void)
/* figure out which /proc/dev/net format to use */
{
    FILE *fp = popen("uname -r", "r");    /* still wins if /proc is out */

    /* pre-linux-2.2 format -- transmit packet count in 8th field */
    netdevfmt = "%d %d %*d %*d %*d %d %*d %d %*d %*d %*d %*d %d";

    if (!fp)
      return;
    else
    {
      int major, minor;

      if (fscanf(fp, "%d.%d.%*d", &major, &minor) >= 2
                              && major >= 2 && minor >= 2)
          /* Linux 2.2 -- transmit packet count in 10th field */
          netdevfmt = "%d %d %*d %*d %*d %d %*d %*d %*d %d %*d %*d %d";
      pclose(fp);
    }
}

static int _get_ifinfoGT_(int socket_fd, FILE *stats_file, const char *ifname,
            ifinfo_t *ifinfo)
/* get active network interface information - return non-zero upon success */
{
      int namelen = strlen(ifname);
      struct ifreq request;
      char *cp, buffer[256];
      int found = 0;
      int counts[4];

      /* initialize result */
      memset((char *) ifinfo, 0, sizeof(ifinfo_t));

      /* 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;
                  if (sscanf(cp, netdevfmt,
                           counts, counts+1, counts+2, 
                           counts+3,&found)>4) { /* found = dummy */
                          /* newer kernel with byte counts */
                          ifinfo->rx_packets=counts[1];
                          ifinfo->tx_packets=counts[3];
                  } else {
                          /* older kernel, no byte counts */
                          ifinfo->rx_packets=counts[0];
                          ifinfo->tx_packets=counts[2];
                  }
                        found = 1;
            }
      }
        if (!found) return (FALSE);

      /* see if the interface is up */
      strcpy(request.ifr_name, ifname);
      if (ioctl(socket_fd, SIOCGIFFLAGS, &request) < 0)
            return(FALSE);
      if (!(request.ifr_flags & IFF_RUNNING))
            return(FALSE);

      /* get the (local) 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 (remote) IP address */
      ifinfo->dstaddr.s_addr = 0;
      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;
          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 = FALSE;
      else
      {
          char    *sp = strchr(ifname, '/');

          if (sp)
            *sp = '\0';
          result = _get_ifinfoGT_(socket_fd, stats_file, ifname, ifinfo);
          if (sp)
            *sp = '/';
      }
      if (socket_fd >= 0)
          SockClose(socket_fd);
      if (stats_file)
          fclose(stats_file); /* not checking should be safe, mode was "r" */
      return(result);
}

#elif defined __FreeBSD__

#if defined __FreeBSD_USE_KVM

static kvm_t *kvmfd;
static struct nlist symbols[] = 
{
      {"_ifnet"},
      {NULL}
};
static u_long     ifnet_savedaddr;
static gid_t      if_rgid;
static gid_t      if_egid;

void 
interface_set_gids(gid_t egid, gid_t rgid)
{
      if_rgid = rgid;
      if_egid = egid;
}

static int 
openkvm(void)
{
      if ((kvmfd = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL)) == NULL)
            return FALSE;
      
      if (kvm_nlist(kvmfd, symbols) < 0)
            return FALSE;
         
      if (kvm_read(kvmfd, (unsigned long) symbols[0].n_value, &ifnet_savedaddr, sizeof(unsigned long)) == -1)
            return FALSE;
            
      return TRUE;
}

static int 
get_ifinfo(const char *ifname, ifinfo_t *ifinfo)
{
      char              tname[16];
      char              iname[16];
      struct ifnet              ifnet;
      unsigned long     ifnet_addr = ifnet_savedaddr;
#if __FreeBSD_version >= 300001
      struct ifnethead  ifnethead;
      struct ifaddrhead ifaddrhead;
#endif
      struct ifaddr           ifaddr;
      unsigned long           ifaddr_addr;
      struct sockaddr         sa;
      unsigned long           sa_addr;
      uint              i;
      
      if (if_egid)
            setegid(if_egid);
      
      for (i = 0; ifname[i] && ifname[i] != '/'; i++)
            iname[i] = ifname[i];
            
      iname[i] = '\0';
      
      if (!kvmfd)
      {
            if (!openkvm())
            {
                  report(stderr, 0, GT_("Unable to open kvm interface. Make sure fetchmail is SGID kmem."));
                  if (if_egid)
                        setegid(if_rgid);
                  exit(1);
            }
      }

#if __FreeBSD_version >= 300001
      kvm_read(kvmfd, ifnet_savedaddr, (char *) &ifnethead, sizeof ifnethead);
      ifnet_addr = (u_long) ifnethead.tqh_first;
#else
      ifnet_addr = ifnet_savedaddr;
#endif

      while (ifnet_addr)
      {
            kvm_read(kvmfd, ifnet_addr, &ifnet, sizeof(ifnet));
            kvm_read(kvmfd, (unsigned long) ifnet.if_name, tname, sizeof tname);
#ifdef HAVE_SNPRINTF
            snprintf(tname, sizeof tname,
#else
            sprintf(tname,
#endif
                  "%s%d", tname, ifnet.if_unit);

            if (!strcmp(tname, iname))
            {
                  if (!(ifnet.if_flags & IFF_UP))
                  {
                        if (if_egid)
                              setegid(if_rgid);
                        return 0;
                  }
                        
                  ifinfo->rx_packets = ifnet.if_ipackets;
                  ifinfo->tx_packets = ifnet.if_opackets;

#if __FreeBSD_version >= 300001
                  ifaddr_addr = (u_long) ifnet.if_addrhead.tqh_first;
#else
                  ifaddr_addr = (u_long) ifnet.if_addrlist;
#endif
                  
                  while(ifaddr_addr)
                  {
                        kvm_read(kvmfd, ifaddr_addr, &ifaddr, sizeof(ifaddr));
                        kvm_read(kvmfd, (u_long)ifaddr.ifa_addr, &sa, sizeof(sa));
                        
                        if (sa.sa_family != AF_INET)
                        {
#if __FreeBSD_version >= 300001
                              ifaddr_addr = (u_long) ifaddr.ifa_link.tqe_next;
#else
                              ifaddr_addr = (u_long) ifaddr.ifa_next;
#endif
                              continue;
                        }
                  
                        ifinfo->addr.s_addr = *(u_long *)(sa.sa_data + 2);
                        kvm_read(kvmfd, (u_long)ifaddr.ifa_dstaddr, &sa, sizeof(sa));
                        ifinfo->dstaddr.s_addr = *(u_long *)(sa.sa_data + 2);
                        kvm_read(kvmfd, (u_long)ifaddr.ifa_netmask, &sa, sizeof(sa));
                        ifinfo->netmask.s_addr = *(u_long *)(sa.sa_data + 2);

                        if (if_egid)
                              setegid(if_rgid);

                        return 1;
                  }
                  
                  if (if_egid)
                        setegid(if_rgid);
                  
                  return 0;
            }

#if __FreeBSD_version >= 300001
            ifnet_addr = (u_long) ifnet.if_link.tqe_next;
#else
            ifnet_addr = (unsigned long) ifnet.if_next;
#endif
      }

      if (if_egid)
            setegid(if_rgid);
      
      return 0;
}

#else /* Do not use KVM on FreeBSD */

/*
 * Expand the compacted form of addresses as returned via the
 * configuration read via sysctl().
 */

static void
rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
{
    struct sockaddr *sa;
    int i;

#define ROUNDUP(a) \
      ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))

    memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
    for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
      if ((rtinfo->rti_addrs & (1 << i)) == 0)
          continue;
      rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
      ADVANCE(cp, sa);
    }

#undef ROUNDUP
#undef ADVANCE
}

static int
get_ifinfo(const char *ifname, ifinfo_t *ifinfo)
{
    uint          i;
    int                 rc = 0;
    int                 ifindex = -1;
    size_t        needed;
    char          *buf = NULL;
    char          *lim = NULL;
    char          *next = NULL;
    struct if_msghdr    *ifm;
    struct ifa_msghdr   *ifam;
    struct sockaddr_in  *sin;
    struct sockaddr_dl  *sdl;
    struct rt_addrinfo  info;
    char          iname[16];
    int                 mib[6];

    memset(ifinfo, 0, sizeof(ifinfo));

    /* trim interface name */

    for (i = 0; i < sizeof(iname) && ifname[i] && ifname[i] != '/'; i++)
      iname[i] = ifname[i];
      
    if (i == 0 || i == sizeof(iname))
    {
      report(stderr, GT_("Unable to parse interface name from %s"), ifname);
      return 0;
    }

    iname[i] = 0;


    /* get list of existing interfaces */

    mib[0] = CTL_NET;
    mib[1] = PF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_INET;         /* Only IP addresses please. */
    mib[4] = NET_RT_IFLIST;
    mib[5] = 0;               /* List all interfaces. */


    /* Get interface data. */

    if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1)
    {
      report(stderr, 
          GT_("get_ifinfo: sysctl (iflist estimate) failed"));
      exit(1);
    }
    if ((buf = malloc(needed)) == NULL)
    {
      report(stderr, 
          GT_("get_ifinfo: malloc failed"));
      exit(1);
    }
    if (sysctl(mib, 6, buf, &needed, NULL, 0) == -1)
    {
      report(stderr, 
          GT_("get_ifinfo: sysctl (iflist) failed"));
      exit(1);
    }

    lim = buf+needed;


    /* first look for the interface information */

    next = buf;
    while (next < lim)
    {
      ifm = (struct if_msghdr *)next;
      next += ifm->ifm_msglen;

      if (ifm->ifm_version != RTM_VERSION) 
      {
          report(stderr, 
            GT_("Routing message version %d not understood."),
            ifm->ifm_version);
          exit(1);
      }

      if (ifm->ifm_type == RTM_IFINFO)
      {
          sdl = (struct sockaddr_dl *)(ifm + 1);

          if (!(strlen(iname) == sdl->sdl_nlen 
            && strncmp(iname, sdl->sdl_data, sdl->sdl_nlen) == 0))
          {
            continue;
          }

          if ( !(ifm->ifm_flags & IFF_UP) )
          {
            /* the interface is down */
            goto get_ifinfo_end;
          }

          ifindex = ifm->ifm_index;
          ifinfo->rx_packets = ifm->ifm_data.ifi_ipackets;
          ifinfo->tx_packets = ifm->ifm_data.ifi_opackets;

          break;
      }
    }

    if (ifindex < 0)
    {
      /* we did not find an interface with a matching name */
      report(stderr, GT_("No interface found with name %s"), iname);
      goto get_ifinfo_end;
    }

    /* now look for the interface's IP address */

    next = buf;
    while (next < lim)
    {
      ifam = (struct ifa_msghdr *)next;
      next += ifam->ifam_msglen;

      if (ifindex > 0
          && ifam->ifam_type == RTM_NEWADDR
          && ifam->ifam_index == ifindex)
      {
          /* Expand the compacted addresses */
          info.rti_addrs = ifam->ifam_addrs;
          rt_xaddrs((char *)(ifam + 1), 
                  ifam->ifam_msglen + (char *)ifam,
                  &info);

          /* Check for IPv4 address information only */
          if (info.rti_info[RTAX_IFA]->sa_family != AF_INET)
          {
            continue;
          }

          rc = 1;

          sin = (struct sockaddr_in *)info.rti_info[RTAX_IFA];
          if (sin)
          {
            ifinfo->addr = sin->sin_addr;
          }

          sin = (struct sockaddr_in *)info.rti_info[RTAX_NETMASK];
          if (!sin)
          {
            ifinfo->netmask = sin->sin_addr;
          }

          /* note: RTAX_BRD contains the address at the other
           * end of a point-to-point link or the broadcast address
           * of non point-to-point link
           */
          sin = (struct sockaddr_in *)info.rti_info[RTAX_BRD];
          if (!sin)
          {
            ifinfo->dstaddr = sin->sin_addr;
          }

          break;
      }
    }

    if (rc == 0)
    {
      report(stderr, GT_("No IP address found for %s"), iname);
    }

get_ifinfo_end:
    free(buf);
    return rc;
}

#endif /* __FREEBSD_USE_SYSCTL_GET_IFFINFO */

#endif /* defined __FreeBSD__ */


#ifndef HAVE_INET_ATON
/*
 * Note: This is not a true replacement for inet_aton(), as it won't
 * do the right thing on "255.255.255.255" (which translates to -1 on
 * most machines).  Fortunately this code will be used only if you're
 * on an older Linux that lacks a real implementation.
 */
#ifdef HAVE_NETINET_IN_SYSTM_H
# include <sys/types.h>
# include <netinet/in_systm.h>
#endif

#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <string.h>

static int inet_aton(const char *cp, struct in_addr *inp) {
    long addr;

    addr = inet_addr(cp);
    if (addr == ((long) -1)) return 0;

    memcpy(inp, &addr, sizeof(addr));
    return 1;
}
#endif /* HAVE_INET_ATON */

void interface_parse(char *buf, struct hostdata *hp)
/* parse 'interface' specification */
{
      char *cp1, *cp2;

      hp->interface = xstrdup(buf);

      /* find and isolate just the IP address */
      if (!(cp1 = strchr(buf, '/')))
      {
            (void) report(stderr,
                        GT_("missing IP interface address\n"));
            exit(PS_SYNTAX);
      }
      *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 */
      hp->interface_pair = (struct interface_pair_s *)xmalloc(sizeof(struct interface_pair_s));
      if (!inet_aton(cp1, &hp->interface_pair->interface_address))
      {
            (void) report(stderr,
                        GT_("invalid IP interface address\n"));
            exit(PS_SYNTAX);
      }
      if (!inet_aton(cp2, &hp->interface_pair->interface_mask))
      {
            (void) report(stderr,
                        GT_("invalid IP interface mask\n"));
            exit(PS_SYNTAX);
      }
      /* apply the mask now to the IP address (range) required */
      hp->interface_pair->interface_address.s_addr &=
            hp->interface_pair->interface_mask.s_addr;

      /* restore original interface string (for configuration dumper) */
      *--cp1 = '/';
      return;
}

void interface_note_activity(struct hostdata *hp)
/* save interface I/O counts */
{
      ifinfo_t ifinfo;
      struct query *ctl;

      /* if not monitoring link, all done */
      if (!hp->monitor)
            return;

      /* get the current I/O stats for the monitored link */
      if (get_ifinfo(hp->monitor, &ifinfo))
            /* update this and preceeding host entries using the link
               (they were already set during this pass but the I/O
               count has now changed and they need to be re-updated)
            */
            for (ctl = querylist; ctl; ctl = ctl->next) {
                  if (ctl->server.monitor && !strcmp(hp->monitor, ctl->server.monitor))
                        ctl->server.monitor_io =
                              ifinfo.rx_packets + ifinfo.tx_packets;
                  /* do NOT update host entries following this one */
                  if (&ctl->server == hp)
                        break;
            }

#ifdef      ACTIVITY_DEBUG
      (void) report(stdout, 
                  GT_("activity on %s -noted- as %d\n"), 
                  hp->monitor, hp->monitor_io);
#endif
}

int interface_approve(struct hostdata *hp, flag domonitor)
/* return TRUE if OK to poll, FALSE otherwise */
{
      ifinfo_t ifinfo;

      /* check interface IP address (range), if specified */
      if (hp->interface) {
            /* get interface info */
            if (!get_ifinfo(hp->interface, &ifinfo)) {
                  (void) report(stdout, 
                              GT_("skipping poll of %s, %s down\n"),
                              hp->pollname, hp->interface);
                  return(FALSE);
            }
            /* check the IP addresses (range) */
            if    (!(
                        /* check remote IP address */
                        ((ifinfo.dstaddr.s_addr != 0) &&
                        (ifinfo.dstaddr.s_addr &
                        hp->interface_pair->interface_mask.s_addr) ==
                        hp->interface_pair->interface_address.s_addr)
                        ||
                        /* check local IP address */
                        ((ifinfo.addr.s_addr &
                        hp->interface_pair->interface_mask.s_addr) ==
                        hp->interface_pair->interface_address.s_addr)
                  ) )
            {
                  (void) report(stdout,
                        GT_("skipping poll of %s, %s IP address excluded\n"),
                        hp->pollname, hp->interface);
                  return(FALSE);
            }
      }

      /* if not monitoring link, all done */
      if (!domonitor || !hp->monitor)
            return(TRUE);

#ifdef      ACTIVITY_DEBUG
      (void) report(stdout, 
                  GT_("activity on %s checked as %d\n"), 
                  hp->monitor, hp->monitor_io);
#endif
      /* if monitoring, check link for activity if it is up */
      if (get_ifinfo(hp->monitor, &ifinfo))
      {
          int diff = (ifinfo.rx_packets + ifinfo.tx_packets)
                                          - hp->monitor_io;

          /*
           * There are three cases here:
           *
           * (a) If the new packet count is less than the recorded one,
           * probably pppd was restarted while fetchmail was running.
           * Don't skip.
           *
           * (b) newpacket count is greater than the old packet count,
           * but the difference is small and may just reflect the overhead
           * of a link shutdown.  Skip.
           *
           * (c) newpacket count is greater than the old packet count,
           * and the difference is large. Connection is live.  Don't skip.
           */
          if (diff >= 0 && diff <= MONITOR_SLOP)
          {
            (void) report(stdout, 
                        GT_("skipping poll of %s, %s inactive\n"),
                        hp->pollname, hp->monitor);
            return(FALSE);
          }
      }

#ifdef ACTIVITY_DEBUG
       report(stdout, GT_("activity on %s was %d, is %d\n"),
             hp->monitor, hp->monitor_io,
             ifinfo.rx_packets + ifinfo.tx_packets);
#endif

      return(TRUE);
}
#endif /* (defined(linux) && !defined(INET6_ENABLE)) || defined(__FreeBSD__) */

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