/*

 *

 *   Authors:

 *    Lars Fenneberg    <lf@elemental.net>

 *

 *   This software is Copyright 1996,1997 by the above mentioned author(s),

 *   All Rights Reserved.

 *

 *   The license which is distributed with this software in the file COPYRIGHT

 *   applies to this software. If your distribution is missing this file, you

 *   may request it from https://github.com/radvd-project/radvd/issues

 *

 */

#include "config.h"

#include "defaults.h"

#include "includes.h"

#include "netlink.h"

#include "pathnames.h"

#include "radvd.h"

#ifndef IPV6_ADDR_LINKLOCAL

#define IPV6_ADDR_LINKLOCAL 0x0020U

#endif

#ifndef ARPHRD_6LOWPAN

#define ARPHRD_6LOWPAN 825 /* IPv6 over LoWPAN */

#endif

static char const *hwstr(unsigned short sa_family);

uint32_t get_interface_linkmtu(const char *);

/*

 * this function gets the hardware type and address of an interface,

 * determines the link layer token length and checks it against

 * the defined prefixes

 */

int update_device_info(int sock, struct Interface *iface)

{

  struct ifreq ifr;

  int ra_option_size_step = 0;

  memset(&ifr, 0, sizeof(ifr));

  strlcpy(ifr.ifr_name, iface->props.name, sizeof(ifr.ifr_name));

  if (ioctl(sock, SIOCGIFMTU, &ifr) < 0) {

    flog(LOG_ERR, "ioctl(SIOCGIFMTU) failed on %s: %s", iface->props.name, strerror(errno));

    return -1;

  }

  iface->sllao.if_maxmtu = ifr.ifr_mtu;

  dlog(LOG_DEBUG, 3, "%s mtu: %d", iface->props.name, ifr.ifr_mtu);

  /* RFC 2460: 5. Packet Size Issues */

  /* Get the smallest MTU between the SIOCGIFMTU value and the protocol MTU

   * /proc/sys/net/ipv6/conf/eth0/mtu

   * Because the protocol MTU _may_ be different than the physical link MTU

   *

   * If Link-layer MTU <= 1280: use 1280 (enforced by iface->AdvRAMTU)

   * If Link-layer MTU > 1280: use the lower of:

   *   - RA MTU

   *   - link-layer MTU

   *   - per-protocol MTU

   */

  iface->props.max_ra_option_size = iface->AdvRAMTU;

  dlog(LOG_DEBUG, 5, "%s max ra option size (step %d): %d",iface->props.name, ra_option_size_step++, iface->props.max_ra_option_size);

  iface->props.max_ra_option_size = MIN(iface->props.max_ra_option_size, MAX(iface->sllao.if_maxmtu, RFC2460_MIN_MTU));

  dlog(LOG_DEBUG, 5, "%s max ra option size (step %d): %d",iface->props.name, ra_option_size_step++, iface->props.max_ra_option_size);

  iface->props.max_ra_option_size =

      MIN(iface->props.max_ra_option_size, MAX(get_interface_linkmtu(iface->props.name), RFC2460_MIN_MTU));

  dlog(LOG_DEBUG, 5, "%s max ra option size (step %d): %d",iface->props.name, ra_option_size_step++, iface->props.max_ra_option_size);

  if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0) {

    flog(LOG_ERR, "ioctl(SIOCGIFHWADDR) failed on %s: %s", iface->props.name, strerror(errno));

    return -1;

  }

  dlog(LOG_DEBUG, 3, "%s hardware type: %s", iface->props.name, hwstr(ifr.ifr_hwaddr.sa_family));

  switch (ifr.ifr_hwaddr.sa_family) {

  case ARPHRD_ETHER:

    iface->sllao.if_hwaddr_len = 48;

    iface->sllao.if_prefix_len = 64;

    char hwaddr[3 * 6];

    sprintf(hwaddr, "%02x:%02x:%02x:%02x:%02x:%02x", (unsigned char)ifr.ifr_hwaddr.sa_data[0],

      (unsigned char)ifr.ifr_hwaddr.sa_data[1], (unsigned char)ifr.ifr_hwaddr.sa_data[2],

      (unsigned char)ifr.ifr_hwaddr.sa_data[3], (unsigned char)ifr.ifr_hwaddr.sa_data[4],

      (unsigned char)ifr.ifr_hwaddr.sa_data[5]);

    dlog(LOG_DEBUG, 3, "%s hardware address: %s", iface->props.name, hwaddr);

    iface->props.max_ra_option_size -= 14; /* RFC 2464 */

    break;

#ifdef ARPHRD_FDDI

  case ARPHRD_FDDI:

    iface->sllao.if_hwaddr_len = 48;

    iface->sllao.if_prefix_len = 64;

    iface->props.max_ra_option_size -= 22; /* RFC 2109 */

    break;

#endif /* ARPHDR_FDDI */

#ifdef ARPHRD_ARCNET

  case ARPHRD_ARCNET:

    iface->sllao.if_hwaddr_len = 8;

    iface->sllao.if_prefix_len = -1;

    iface->sllao.if_maxmtu = -1;

    /* RFC1201: fragmentation handled at a lower layer.

     * native packet size is 256-512 bytes */

    iface->props.max_ra_option_size -= 0;

    break;

#endif /* ARPHDR_ARCNET */

  case ARPHRD_6LOWPAN:

#ifdef HAVE_NETLINK

    /* hwaddr length differs on some L2 type lets detect them */

    iface->sllao.if_hwaddr_len = netlink_get_device_addr_len(iface);

    if (iface->sllao.if_hwaddr_len != -1) {

      iface->sllao.if_hwaddr_len *= 8;

      iface->sllao.if_prefix_len = 64;

    } else {

      iface->sllao.if_prefix_len = -1;

    }

#else

    iface->sllao.if_hwaddr_len = -1;

    iface->sllao.if_prefix_len = -1;

#endif

    /* RFC4944: fragmentation handled at a lower layer.

     * native packet size maxes at 127 bytes */

    iface->props.max_ra_option_size -= 0;

    break;

  default:

    iface->sllao.if_hwaddr_len = -1;

    iface->sllao.if_prefix_len = -1;

    iface->sllao.if_maxmtu = -1;

    /* Assume fragmentation handled at a lower layer. */

    iface->props.max_ra_option_size -= 0;

    break;

  }

  dlog(LOG_DEBUG, 5, "%s max ra option size (step %d): %d",iface->props.name, ra_option_size_step++, iface->props.max_ra_option_size);

  dlog(LOG_DEBUG, 3, "%s link layer token length: %d", iface->props.name, iface->sllao.if_hwaddr_len);

  dlog(LOG_DEBUG, 3, "%s prefix length: %d", iface->props.name, iface->sllao.if_prefix_len);

  if (iface->sllao.if_hwaddr_len != -1) {

    unsigned int if_hwaddr_len_bytes = (iface->sllao.if_hwaddr_len + 7) >> 3;

    if (if_hwaddr_len_bytes > sizeof(iface->sllao.if_hwaddr)) {

      flog(LOG_ERR, "%s address length too big: %d", iface->props.name, if_hwaddr_len_bytes);

      return -2;

    }

    memcpy(iface->sllao.if_hwaddr, ifr.ifr_hwaddr.sa_data, if_hwaddr_len_bytes);

    char zero[sizeof(iface->props.if_addr)];

    memset(zero, 0, sizeof(zero));

    if (!memcmp(iface->sllao.if_hwaddr, zero, if_hwaddr_len_bytes))

      flog(LOG_WARNING, "WARNING, MAC address on %s is all zero!", iface->props.name);

  }

  struct AdvPrefix *prefix = iface->AdvPrefixList;

  while (prefix) {

    if ((iface->sllao.if_prefix_len != -1) && (iface->sllao.if_prefix_len != prefix->PrefixLen)) {

      flog(LOG_WARNING, "%s prefix length should be: %d", iface->props.name, iface->sllao.if_prefix_len);

    }

    prefix = prefix->next;

  }

  // Regardless of link-layer, every RA message will have an IPV6 header & RA header

  iface->props.max_ra_option_size -= sizeof(struct ip6_hdr);

  dlog(LOG_DEBUG, 5, "%s max ra option size (step %d): %d",iface->props.name, ra_option_size_step++, iface->props.max_ra_option_size);

  iface->props.max_ra_option_size -= sizeof(struct nd_router_advert);

  dlog(LOG_DEBUG, 5, "%s max ra option size (step %d): %d",iface->props.name, ra_option_size_step++, iface->props.max_ra_option_size);

  dlog(LOG_DEBUG, 3, "%s max ra option size (final): %d", iface->props.name, iface->props.max_ra_option_size);

  return 0;

}

int setup_allrouters_membership(int sock, struct Interface *iface)

{

  struct ipv6_mreq mreq;

  memset(&mreq, 0, sizeof(mreq));

  mreq.ipv6mr_interface = iface->props.if_index;

  /* ipv6-allrouters: ff02::2 */

  mreq.ipv6mr_multiaddr.s6_addr32[0] = htonl(0xFF020000);

  mreq.ipv6mr_multiaddr.s6_addr32[3] = htonl(0x2);

  if (setsockopt(sock, SOL_IPV6, IPV6_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {

    /* linux-2.6.12-bk4 returns error with HUP signal but keep listening */

    if (errno != EADDRINUSE) {

      flog(LOG_ERR, "can't join ipv6-allrouters on %s", iface->props.name);

      return -1;

    }

  }

  return 0;

}

int cleanup_allrouters_membership(int sock, struct Interface *iface)

{

  struct ipv6_mreq mreq;

  memset(&mreq, 0, sizeof(mreq));

  mreq.ipv6mr_interface = iface->props.if_index;

  /* ipv6-allrouters: ff02::2 */

  mreq.ipv6mr_multiaddr.s6_addr32[0] = htonl(0xFF020000);

  mreq.ipv6mr_multiaddr.s6_addr32[3] = htonl(0x2);

  setsockopt(sock, SOL_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq));

  return 0;

}

uint32_t get_interface_linkmtu(const char *iface)

{

  int value;

  FILE *fp = NULL;

  char proc_path[sizeof(PROC_SYS_IP6_LINKMTU) + IFNAMSIZ];

  snprintf(proc_path, sizeof(PROC_SYS_IP6_LINKMTU) + IFNAMSIZ, PROC_SYS_IP6_LINKMTU, iface);

  fp = fopen(proc_path, "r");

  if (fp) {

    int rc = fscanf(fp, "%d", &value);

    if (rc != 1) {

      flog(LOG_ERR, "cannot read value from %s: %s", proc_path, strerror(errno));

      exit(1);

    }

    fclose(fp);

  } else {

    flog(LOG_DEBUG, "Correct IPv6 MTU entry not found, "

        "perhaps the procfs is disabled, "

        "or the kernel interface has changed?");

    value = 1280; /* RFC2460: section 5 */

  }

  return value;

}

int set_interface_linkmtu(const char *iface, uint32_t mtu) { return privsep_interface_linkmtu(iface, mtu); }

int set_interface_curhlim(const char *iface, uint8_t hlim) { return privsep_interface_curhlim(iface, hlim); }

int set_interface_reachtime(const char *iface, uint32_t rtime) { return privsep_interface_reachtime(iface, rtime); }

int set_interface_retranstimer(const char *iface, uint32_t rettimer) { return privsep_interface_retranstimer(iface, rettimer); }

int check_ip6_iface_forwarding(const char *iface)

{

  int value = -1;

  FILE *fp = NULL;

  char path[sizeof(PROC_SYS_IP6_IFACE_FORWARDING) + IFNAMSIZ];

  snprintf(path, sizeof(PROC_SYS_IP6_IFACE_FORWARDING) + IFNAMSIZ, PROC_SYS_IP6_IFACE_FORWARDING, iface);

  fp = fopen(path, "r");

  if (fp) {

    int rc = fscanf(fp, "%d", &value);

    if (rc != 1) {

      flog(LOG_ERR, "cannot read value from %s: %s", path, strerror(errno));

      exit(1);

    }

    fclose(fp);

  } else {

    flog(LOG_DEBUG, "Correct IPv6 forwarding procfs entry for interface "

        "not found, perhaps the procfs is disabled, "

        "or the kernel interface has changed?");

    value = -1;

  }

  return value;

}

int check_ip6_forwarding(void)

{

  int value;

  FILE *fp = NULL;

  fp = fopen(PROC_SYS_IP6_FORWARDING, "r");

  if (fp) {

    int rc = fscanf(fp, "%d", &value);

    if (rc != 1) {

      flog(LOG_ERR, "cannot read value from %s: %s", PROC_SYS_IP6_FORWARDING, strerror(errno));

      exit(1);

    }

    fclose(fp);

  } else {

    flog(LOG_DEBUG, "Correct IPv6 forwarding procfs entry not found, "

        "perhaps the procfs is disabled, "

        "or the kernel interface has changed?");

    value = -1;

  }

#ifdef HAVE_SYSCTL

  int forw_sysctl[] = {SYSCTL_IP6_FORWARDING};

  size_t size = sizeof(value);

  if (!fp && sysctl(forw_sysctl, sizeof(forw_sysctl) / sizeof(forw_sysctl[0]), &value, &size, NULL, 0) < 0) {

    flog(LOG_DEBUG, "Correct IPv6 forwarding sysctl branch not found, "

        "perhaps the kernel interface has changed?");

    return 0; /* this is of advisory value only */

  }

#endif

  /* Linux allows the forwarding value to be either 1 or 2.

   * https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/ip-sysctl.txt?id=ae8abfa00efb8ec550f772cbd1e1854977d06212#n1078

   *

   * The value 2 indicates forwarding is enabled and that *AS* *WELL* router solicitations are being done.

   *

   * Which is sometimes used on routers performing RS on their WAN (ppp, etc.) links

   */

  static int warned = 0;

  if (!warned && value != 1 && value != 2) {

    warned = 1;

    flog(LOG_DEBUG, "IPv6 forwarding setting is: %u, should be 1 or 2", value);

    return -1;

  }

  return 0;

}

static char const *hwstr(unsigned short sa_family)

{

  char const *rc = 0;

  switch (sa_family) {

  case ARPHRD_NETROM:

    rc = "ARPHRD_NETROM";

    break;

  case ARPHRD_ETHER:

    rc = "ARPHRD_ETHER";

    break;

  case ARPHRD_EETHER:

    rc = "ARPHRD_EETHER";

    break;

  case ARPHRD_AX25:

    rc = "ARPHRD_AX25";

    break;

  case ARPHRD_PRONET:

    rc = "ARPHRD_PRONET";

    break;

  case ARPHRD_CHAOS:

    rc = "ARPHRD_CHAOS";

    break;

  case ARPHRD_IEEE802:

    rc = "ARPHRD_IEEE802";

    break;

  case ARPHRD_APPLETLK:

    rc = "ARPHRD_APPLETLK";

    break;

  case ARPHRD_DLCI:

    rc = "ARPHRD_DLCI";

    break;

  case ARPHRD_ATM:

    rc = "ARPHRD_ATM";

    break;

  case ARPHRD_METRICOM:

    rc = "ARPHRD_METRICOM";

    break;

  case ARPHRD_IEEE1394:

    rc = "ARPHRD_IEEE1394";

    break;

  case ARPHRD_EUI64:

    rc = "ARPHRD_EUI64";

    break;

  case ARPHRD_INFINIBAND:

    rc = "ARPHRD_INFINIBAND";

    break;

  case ARPHRD_SLIP:

    rc = "ARPHRD_SLIP";

    break;

  case ARPHRD_CSLIP:

    rc = "ARPHRD_CSLIP";

    break;

  case ARPHRD_SLIP6:

    rc = "ARPHRD_SLIP6";

    break;

  case ARPHRD_CSLIP6:

    rc = "ARPHRD_CSLIP6";

    break;

  case ARPHRD_RSRVD:

    rc = "ARPHRD_RSRVD";

    break;

  case ARPHRD_ADAPT:

    return "ARPHRD_ADAPT";

    break;

  case ARPHRD_ROSE:

    rc = "ARPHRD_ROSE";

    break;

  case ARPHRD_X25:

    rc = "ARPHRD_X25";

    break;

  case ARPHRD_HWX25:

    rc = "ARPHRD_HWX25";

    break;

  case ARPHRD_PPP:

    rc = "ARPHRD_PPP";

    break;

  case ARPHRD_CISCO:

    rc = "ARPHRD_CISCO";

    break;

  case ARPHRD_LAPB:

    rc = "ARPHRD_LAPB";

    break;

  case ARPHRD_DDCMP:

    rc = "ARPHRD_DDCMP";

    break;

  case ARPHRD_RAWHDLC:

    rc = "ARPHRD_RAWHDLC";

    break;

  case ARPHRD_TUNNEL:

    rc = "ARPHRD_TUNNEL";

    break;

  case ARPHRD_TUNNEL6:

    rc = "ARPHRD_TUNNEL6";

    break;

  case ARPHRD_FRAD:

    rc = "ARPHRD_FRAD";

    break;

  case ARPHRD_SKIP:

    rc = "ARPHRD_SKIP";

    break;

  case ARPHRD_LOOPBACK:

    rc = "ARPHRD_LOOPBACK";

    break;

  case ARPHRD_LOCALTLK:

    rc = "ARPHRD_LOCALTLK";

    break;

  case ARPHRD_BIF:

    rc = "ARPHRD_BIF";

    break;

  case ARPHRD_SIT:

    rc = "ARPHRD_SIT";

    break;

  case ARPHRD_IPDDP:

    rc = "ARPHRD_IPDDP";

    break;

  case ARPHRD_IPGRE:

    rc = "ARPHRD_IPGRE";

    break;

  case ARPHRD_PIMREG:

    rc = "ARPHRD_PIMREG";

    break;

  case ARPHRD_HIPPI:

    rc = "ARPHRD_HIPPI";

    break;

  case ARPHRD_ASH:

    rc = "ARPHRD_ASH";

    break;

  case ARPHRD_ECONET:

    rc = "ARPHRD_ECONET";

    break;

  case ARPHRD_IRDA:

    rc = "ARPHRD_IRDA";

    break;

  case ARPHRD_FCPP:

    rc = "ARPHRD_FCPP";

    break;

  case ARPHRD_FCAL:

    rc = "ARPHRD_FCAL";

    break;

  case ARPHRD_FCPL:

    rc = "ARPHRD_FCPL";

    break;

  case ARPHRD_FCFABRIC:

    rc = "ARPHRD_FCFABRIC";

    break;

  case ARPHRD_IEEE802_TR:

    rc = "ARPHRD_IEEE802_TR";

    break;

  case ARPHRD_IEEE80211:

    rc = "ARPHRD_IEEE80211";

    break;

  case ARPHRD_IEEE80211_PRISM:

    rc = "ARPHRD_IEEE80211_PRISM";

    break;

  case ARPHRD_IEEE80211_RADIOTAP:

    rc = "ARPHRD_IEEE80211_RADIOTAP";

    break;

  case ARPHRD_IEEE802154:

    rc = "ARPHRD_IEEE802154";

    break;

#if ARPHRD_IEEE802154_MONITOR

  case ARPHRD_IEEE802154_MONITOR:

    rc = "ARPHRD_IEEE802154_MONITOR";

    break;

#elif ARPHRD_IEEE802154_PHY

  case ARPHRD_IEEE802154_PHY:

    rc = "ARPHRD_IEEE802154_PHY";

    break;

#endif

  case ARPHRD_6LOWPAN:

    rc = "ARPHRD_6LOWPAN";

    break;

  case ARPHRD_VOID:

    rc = "ARPHRD_VOID";

    break;

  case ARPHRD_NONE:

    rc = "ARPHRD_NONE";

    break;

  default:

    rc = "unknown";

    break;

  }

  return rc;

}