From fc06fb62443c135773ee4c05ed83925cc47b046d Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Sat, 7 Jul 2012 10:40:00 +0200
Subject: Implements RDNSS and DNSSL support for RAdv.

---
 proto/radv/packets.c | 181 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 177 insertions(+), 4 deletions(-)

(limited to 'proto/radv/packets.c')

diff --git a/proto/radv/packets.c b/proto/radv/packets.c
index ac59ce94..6fdfcaa3 100644
--- a/proto/radv/packets.c
+++ b/proto/radv/packets.c
@@ -24,8 +24,10 @@ struct radv_ra_packet
 #define OPT_RA_MANAGED 0x80
 #define OPT_RA_OTHER_CFG 0x40
 
-#define OPT_PREFIX 3
-#define OPT_MTU 5
+#define OPT_PREFIX	3
+#define OPT_MTU		5
+#define OPT_RDNSS	25
+#define OPT_DNSSL	31
 
 struct radv_opt_prefix
 {
@@ -50,6 +52,25 @@ struct radv_opt_mtu
   u32 mtu;
 };
 
+struct radv_opt_rdnss
+{
+  u8 type;
+  u8 length;
+  u16 reserved;
+  u32 lifetime;
+  ip_addr servers[];
+};
+
+struct radv_opt_dnssl
+{
+  u8 type;
+  u8 length;
+  u16 reserved;
+  u32 lifetime;
+  char domain[];
+};
+
+
 static struct radv_prefix_config default_prefix = {
   .onlink = 1,
   .autonomous = 1,
@@ -57,6 +78,7 @@ static struct radv_prefix_config default_prefix = {
   .preferred_lifetime = DEFAULT_PREFERRED_LIFETIME
 };
 
+
 static struct radv_prefix_config *
 radv_prefix_match(struct radv_iface *ifa, struct ifa *a)
 {
@@ -78,10 +100,146 @@ radv_prefix_match(struct radv_iface *ifa, struct ifa *a)
   return &default_prefix;
 }
 
+static int
+radv_prepare_rdnss(struct radv_iface *ifa, list *rdnss_list, char **buf, char *bufend)
+{
+  struct radv_rdnss_config *rcf = HEAD(*rdnss_list);
+
+  while(NODE_VALID(rcf))
+  {
+    struct radv_rdnss_config *rcf_base = rcf;
+    struct radv_opt_rdnss *op = (void *) *buf;
+    int max_i = (bufend - *buf - sizeof(struct radv_opt_rdnss)) / sizeof(ip_addr);
+    int i = 0;
+
+    if (max_i < 1)
+      goto too_much;
+
+    op->type = OPT_RDNSS;
+    op->reserved = 0;
+
+    if (rcf->lifetime_mult)
+      op->lifetime = htonl(rcf->lifetime_mult * ifa->cf->max_ra_int);
+    else
+      op->lifetime = htonl(rcf->lifetime);
+
+    while(NODE_VALID(rcf) && 
+	  (rcf->lifetime == rcf_base->lifetime) &&
+	  (rcf->lifetime_mult == rcf_base->lifetime_mult))
+      {
+	if (i >= max_i)
+	  goto too_much;
+
+	op->servers[i] = rcf->server;
+	ipa_hton(op->servers[i]);
+	i++;
+
+	rcf = NODE_NEXT(rcf);
+      }
+  
+    op->length = 1+2*i;
+    *buf += 8 * op->length;
+  }
+
+  return 0;
+
+ too_much:
+  log(L_WARN "%s: Too many RA options on interface %s",
+      ifa->ra->p.name, ifa->iface->name);
+  return -1;
+}
+
+int
+radv_process_domain(struct radv_dnssl_config *cf)
+{
+  /* Format of domain in search list is <size> <label> <size> <label> ... 0 */
+
+  char *dom = cf->domain;
+  char *dom_end = dom; /* Just to  */
+  u8 *dlen_save = &cf->dlen_first;
+  int len;
+
+  while (dom_end)
+  {
+    dom_end = strchr(dom, '.');
+    len = dom_end ? (dom_end - dom) : strlen(dom);
+
+    if (len < 1 || len > 63)
+      return -1;
+
+    *dlen_save = len;
+    dlen_save = (u8 *) dom_end;
+
+    dom += len + 1;
+  }
+
+  len = dom - cf->domain;
+  if (len > 254)
+    return -1;
+
+  cf->dlen_all = len;
+
+  return 0;
+}
+
+static int
+radv_prepare_dnssl(struct radv_iface *ifa, list *dnssl_list, char **buf, char *bufend)
+{
+  struct radv_dnssl_config *dcf = HEAD(*dnssl_list);
+
+  while(NODE_VALID(dcf))
+  {
+    struct radv_dnssl_config *dcf_base = dcf;
+    struct radv_opt_dnssl *op = (void *) *buf;
+    int bsize = bufend - *buf - sizeof(struct radv_opt_dnssl);
+    int bpos = 0;
+
+    if (bsize < 0)
+      goto too_much;
+
+    bsize = bsize & ~7; /* Round down to multiples of 8 */
+
+    op->type = OPT_DNSSL;
+    op->reserved = 0;
+
+    if (dcf->lifetime_mult)
+      op->lifetime = htonl(dcf->lifetime_mult * ifa->cf->max_ra_int);
+    else
+      op->lifetime = htonl(dcf->lifetime);
+
+    while(NODE_VALID(dcf) && 
+	  (dcf->lifetime == dcf_base->lifetime) &&
+	  (dcf->lifetime_mult == dcf_base->lifetime_mult))
+      {
+	if (bpos + dcf->dlen_all + 1 > bsize)
+	  goto too_much;
+
+	op->domain[bpos++] = dcf->dlen_first;
+	memcpy(op->domain + bpos, dcf->domain, dcf->dlen_all);
+	bpos += dcf->dlen_all;
+
+	dcf = NODE_NEXT(dcf);
+      }
+
+    int blen = (bpos + 7) / 8;
+    bzero(op->domain + bpos, 8 * blen - bpos);
+    op->length = 1 + blen;
+    *buf += 8 * op->length;
+  }
+
+  return 0;
+
+ too_much:
+  log(L_WARN "%s: Too many RA options on interface %s",
+      ifa->ra->p.name, ifa->iface->name);
+  return -1;
+}
+
 static void
 radv_prepare_ra(struct radv_iface *ifa)
 {
   struct proto_radv *ra = ifa->ra;
+  struct radv_config *cf = (struct radv_config *) (ra->p.cf);
 
   char *buf = ifa->sk->tbuf;
   char *bufstart = buf;
@@ -121,7 +279,7 @@ radv_prepare_ra(struct radv_iface *ifa)
     if (buf + sizeof(struct radv_opt_prefix) > bufend)
     {
       log(L_WARN "%s: Too many prefixes on interface %s", ra->p.name, ifa->iface->name);
-      break;
+      goto done;
     }
 
     struct radv_opt_prefix *op = (void *) buf;
@@ -137,7 +295,22 @@ radv_prepare_ra(struct radv_iface *ifa)
     ipa_hton(op->prefix);
     buf += sizeof(*op);
   }
-  
+
+  if (! ifa->cf->rdnss_local)
+    if (radv_prepare_rdnss(ifa, &cf->rdnss_list, &buf, bufend) < 0)
+      goto done;
+
+  if (radv_prepare_rdnss(ifa, &ifa->cf->rdnss_list, &buf, bufend) < 0)
+    goto done;
+
+  if (! ifa->cf->dnssl_local)
+    if (radv_prepare_dnssl(ifa, &cf->dnssl_list, &buf, bufend) < 0)
+      goto done;
+
+  if (radv_prepare_dnssl(ifa, &ifa->cf->dnssl_list, &buf, bufend) < 0)
+    goto done;
+
+ done:
   ifa->plen = buf - bufstart;
 }
 
-- 
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