7388 Support DHCP Client FQDN. Allow IAID/DUID for all v4.

*** 20,29 ****
--- 20,30 ----
   */
  
  /*
   * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
+  * Copyright (c) 2016, Chris Fraire <cfraire@me.com>.
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
*** 726,741 ****
                          if (is_ngz)
                                  af = atoi(afstr);
                  } else if (nvlist_lookup_string(nvl, IPADM_NVP_AOBJNAME,
                      &aobjstr) == 0) {
                          /*
!                          * For a static address, we need to search for
!                          * the prefixlen in the nvlist `ifnvl'.
                           */
                          if (nvlist_exists(nvl, IPADM_NVP_IPV4ADDR) ||
!                             nvlist_exists(nvl, IPADM_NVP_IPV6ADDR)) {
!                                 status = i_ipadm_merge_prefixlen_from_nvl(ifnvl,
                                      nvl, aobjstr);
                                  if (status != IPADM_SUCCESS)
                                          continue;
                          }
                          status = i_ipadm_init_addrobj(iph, nvl);
--- 727,743 ----
                          if (is_ngz)
                                  af = atoi(afstr);
                  } else if (nvlist_lookup_string(nvl, IPADM_NVP_AOBJNAME,
                      &aobjstr) == 0) {
                          /*
!                          * For addresses, we need to relocate addrprops from the
!                          * nvlist `ifnvl'.
                           */
                          if (nvlist_exists(nvl, IPADM_NVP_IPV4ADDR) ||
!                             nvlist_exists(nvl, IPADM_NVP_IPV6ADDR) ||
!                             nvlist_exists(nvl, IPADM_NVP_DHCP)) {
!                                 status = i_ipadm_merge_addrprops_from_nvl(ifnvl,
                                      nvl, aobjstr);
                                  if (status != IPADM_SUCCESS)
                                          continue;
                          }
                          status = i_ipadm_init_addrobj(iph, nvl);
*** 953,958 ****
--- 955,1037 ----
          } else {
                  if (darg.rsize != rsize)
                          err = EBADE;
          }
          return (err);
+ }
+ 
+ /*
+  * ipadm_is_nil_hostname() : Determine if the `hostname' is nil: i.e.,
+  *                      NULL, empty, or a single space (e.g., as returned by
+  *                      domainname(1M)/sysinfo).
+  *
+  *   input: const char *: the hostname to inspect;
+  *  output: boolean_t: B_TRUE if `hostname' is not NULL satisfies the
+  *                      criteria above; otherwise, B_FALSE;
+  */
+ 
+ boolean_t
+ ipadm_is_nil_hostname(const char *hostname)
+ {
+         return (hostname == NULL || *hostname == '\0'
+             || (*hostname == ' ' && hostname[1] == '\0'));
+ }
+ 
+ /*
+  * ipadm_is_valid_hostname(): check whether a string is a valid hostname
+  *
+  *   input: const char *: the string to verify as a hostname
+  *  output: boolean_t: B_TRUE if the string is a valid hostname
+  *
+  * Note that we accept host names beginning with a digit, which is not
+  * strictly legal according to the RFCs but is in common practice, so we
+  * endeavour to not break what customers are using.
+  *
+  * RFC 1035 limits a wire-format domain name to 255 octets. For a printable
+  * `hostname' as we have, the limit is therefore 253 characters (excluding
+  * the terminating '\0'--or 254 characters if the last character of
+  * `hostname' is a '.'.
+  *
+  * Excerpt from section 2.3.1., Preferred name syntax:
+  *
+  * <domain> ::= <subdomain> | " "
+  * <subdomain> ::= <label> | <subdomain> "." <label>
+  * <label> ::= <letter> [ [ <ldh-str> ] <let-dig> ]
+  * <ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>
+  * <let-dig-hyp> ::= <let-dig> | "-"
+  * <let-dig> ::= <letter> | <digit>
+  */
+ boolean_t
+ ipadm_is_valid_hostname(const char *hostname)
+ {
+         const size_t MAX_READABLE_NAME_LEN = 253;
+         char last_char;
+         size_t has_last_dot, namelen, i;
+ 
+         if (hostname == NULL)
+                 return B_FALSE;
+ 
+         namelen = strlen(hostname);
+         if (namelen < 1)
+                 return B_FALSE;
+ 
+         last_char = hostname[namelen - 1];
+         has_last_dot = last_char == '.';
+ 
+         if (namelen > MAX_READABLE_NAME_LEN + has_last_dot
+             || last_char == '-')
+                 return B_FALSE;
+ 
+         for (i = 0; hostname[i] != '\0'; i++) {
+                 /*
+                  * As noted above, this deviates from RFC 1035 in that it allows a
+                  * leading digit.
+                  */
+                 if (isalpha(hostname[i]) || isdigit(hostname[i]) ||
+                     (((hostname[i] == '-') || (hostname[i] == '.')) && (i > 0)))
+                         continue;
+ 
+                 return (B_FALSE);
+         }
+ 
+         return B_TRUE;
  }