components/network/dnsmasq/patches/04_dhcp_bind_fix.patch

   1 Patch to address a scalability issue when using dnsmasq in Openstack,
   2 that causes DHCP to be extremely slow.
   3
   4 This patch was developed in-house. Since it is Solaris-specific, it is not
   5 suitable for upstream.
   6
   7 diff --git a/src/dhcp-common.c b/src/dhcp-common.c
   8 index befd8a0..4573730 100644
   9 --- a/src/dhcp-common.c
  10 +++ b/src/dhcp-common.c
  11 @@ -550,6 +550,58 @@ void  bindtodevice(char *device, int fd)
  12        errno != EPERM)
  13      die(_("failed to set SO_BINDTODEVICE on DHCP socket: %s"), NULL, EC_BADNET);
  14  }
  15 +#elif defined(HAVE_SOLARIS_NETWORK)
  16 +int which_ifindex(void)
  17 +{
  18 +  /* If we are doing DHCP on exactly one interface, and using Solaris, we want
  19 +   * to limit packet transmission/reception to that interface using IP_BOUND_IF
  20 +   * for IPv4 and IPV6_BOUND_IF for IPv6. This is for the use case of OpenStack,
  21 +   * which runs a new dnsmasq instance for each network it creates. Without this
  22 +   * socket option, each of the dnsmasq process would unnecessarily process
  23 +   * packets that arrive on other interfaces as well, thus slowing down the
  24 +   * entire DHCP process.
  25 +   */
  26 +
  27 +   struct irec *iface, *found;
  28 +   struct iname *if_tmp;
  29 +
  30 +   if (!daemon->if_names)
  31 +     return -1;
  32 +
  33 +   for (if_tmp = daemon->if_names; if_tmp; if_tmp = if_tmp->next)
  34 +     if (if_tmp->name && (!if_tmp->used || strchr(if_tmp->name, '*')))
  35 +       return -1;
  36 +
  37 +   for (found = NULL, iface = daemon->interfaces; iface; iface = iface->next)
  38 +     if (iface->dhcp_ok)
  39 +       {
  40 +        if (!found)
  41 +          found = iface;
  42 +        else if (strcmp(found->name, iface->name) != 0)
  43 +          return -1; /* more than one. */
  44 +       }
  45 +
  46 +   if (found)
  47 +     return found->index;
  48 +
  49 +   return -1;
  50 +}
  51 +
  52 +void bindtoif(int ifindex, int fd, int is_dhcp6)
  53 +{
  54 +  if (is_dhcp6)
  55 +    {
  56 +      if (setsockopt(fd, IPPROTO_IPV6, IPV6_BOUND_IF, (char *)&ifindex, sizeof(ifindex)) == -1 &&
  57 +          errno != EPERM)
  58 +        die(_("failed to set IPv6_BOUND_IF on DHCP socket: %s"), NULL, EC_BADNET);
  59 +    }
  60 +  else
  61 +    {
  62 +      if (setsockopt(fd, IPPROTO_IP, IP_BOUND_IF, &ifindex, sizeof(ifindex)) == -1 &&
  63 +          errno != EPERM)
  64 +        die(_("failed to set IP_BOUND_IF on DHCP socket: %s"), NULL, EC_BADNET);
  65 +    }
  66 +}
  67  #endif
  68
  69  static const struct opttab_t {
  70 --- a/src/dnsmasq.c     2023-02-02 21:24:24.000000000 +0100
  71 +++ dnsmasq-2.89/src/dnsmasq.c  2023-05-12 10:54:02.094077940 +0200
  72 @@ -66,6 +66,10 @@
  73  #else
  74    int bind_fallback = 0;
  75  #endif
  76 +#if defined(HAVE_SOLARIS_NETWORK)
  77 +  int bound_ifindex = -1;
  78 +  int did_bind = 0;
  79 +#endif
  80  #if defined(HAVE_DHCP) || defined(HAVE_DHCP6)
  81    struct dhcp_context *context;
  82    struct dhcp_relay *relay;
  83 @@ -985,6 +989,10 @@
  84    if (netlink_warn)
  85      my_syslog(LOG_WARNING, netlink_warn);
  86  #  endif
  87 +#  ifdef HAVE_SOLARIS_NETWORK
  88 +  if (did_bind)
  89 +    my_syslog(MS_DHCP | LOG_INFO, _("DHCP, sockets bound exclusively to interface index %d"), bound_ifindex);
  90 +#  endif
  91
  92    /* after dhcp_construct_contexts */
  93    if (daemon->dhcp || daemon->doing_dhcp6)
  94 @@ -1103,6 +1111,23 @@
  95           if (daemon->pxefd != -1)
  96             poll_listen(daemon->pxefd, POLLIN);
  97         }
  98 +#elif defined(HAVE_SOLARIS_NETWORK) && defined(HAVE_DHCP)
  99 +      bound_ifindex = which_ifindex();
 100 +
 101 +      if (daemon->dhcp)
 102 +       {
 103 +          if (!daemon->relay4 && bound_ifindex >= 0)
 104 +            {
 105 +             bindtoif(bound_ifindex, daemon->dhcpfd, 0);
 106 +             did_bind = 1;
 107 +           }
 108 +
 109 +         if (daemon->enable_pxe && bound_ifindex >= 0)
 110 +           {
 111 +              bindtoif(bound_ifindex, daemon->pxefd, 0);
 112 +             did_bind = 1;
 113 +           }
 114 +       }
 115  #endif
 116
 117  #ifdef HAVE_DHCP6
 118 --- a/src/dnsmasq.h     2023-02-02 21:24:24.000000000 +0100
 119 +++ dnsmasq-2.89/src/dnsmasq.h  2023-05-12 11:04:20.988219658 +0200
 120 @@ -153,6 +153,8 @@
 121  #include <sys/prctl.h>
 122  #elif defined(HAVE_SOLARIS_NETWORK)
 123  #include <priv.h>
 124 +int which_ifindex(void);
 125 +void bindtoif(int ifindex, int fd, int is_dhcp6);
 126  #endif
 127
 128  /* Backwards compat with 2.83 */