odhcp6c: preference and status code support in advertise

[odhcp6c.git] / src / dhcpv6.c

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 08e322554ee738c236ffcb00bfd715913c80f09b..d212decaa614ea9413fa7d77670b6a0a9564c5b9 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -574,11 +574,11 @@ static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 
 
 // Collect all advertised servers
-static int dhcpv6_handle_advert(enum dhcpv6_msg orig, _unused const int rc,
+static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
                const void *opt, const void *end)
 {
        uint16_t olen, otype;
-       uint8_t *odata;
+       uint8_t *odata, pref = 0;
        struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
        bool have_na = false;
        int have_pd = 0;
@@ -594,12 +594,29 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, _unused const int rc,
                if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
                        memcpy(cand.duid, odata, olen);
                        cand.duid_len = olen;
-               } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
-                               && odata[1] == DHCPV6_NoPrefixAvail) {
-                       cand.preference -= 2000;
+               } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
+                       int error = ((int)odata[0] << 8 | (int)odata[1]);
+
+                       switch (error) {
+                       case DHCPV6_NoPrefixAvail:
+                               // Status code on global level
+                               if (pd_mode == IA_MODE_FORCE)
+                                       return -1;
+                               cand.preference -= 2000;
+                               break;
+
+                       case DHCPV6_NoAddrsAvail:
+                               // Status code on global level
+                               if (na_mode == IA_MODE_FORCE)
+                                       return -1;
+                               break;
+
+                       default :
+                               break;
+                       }
                } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
                                cand.preference >= 0) {
-                       cand.preference = odata[0];
+                       cand.preference = pref = odata[0];
                } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
                        cand.wants_reconfigure = true;
                } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
@@ -648,7 +665,7 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, _unused const int rc,
                odhcp6c_clear_state(STATE_IA_PD);
        }
 
-       return -1;
+       return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 }
 
 
@@ -679,8 +696,10 @@ static int dhcpv6_commit_advert(void)
                odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
                odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
                accept_reconfig = c->wants_reconfigure;
-               odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
-               odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
+               if (c->ia_na_len)
+                       odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
+               if (c->ia_pd_len)
+                       odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
        }
 
        for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
@@ -691,7 +710,7 @@ static int dhcpv6_commit_advert(void)
 
        if (!c)
                return -1;
-       else if (request_prefix || na_mode != IA_MODE_NONE)
+       else if ((request_prefix && c->ia_pd_len) || (na_mode != IA_MODE_NONE && c->ia_na_len))
                return DHCPV6_STATEFUL;
        else
                return DHCPV6_STATELESS;