Nest: Maintain separate IPv4, IPv6 and LLv6 preferred addresses

Also redesign preferred address selection and update protocols to use
appropriate preferred address.

Based on a previous work by Jan Maria Matejka.

3 files changed, 170 insertions, 76 deletions

diff --git a/nest/iface.c b/nest/iface.c
index f14e70a0..01b1aa48 100644
--- a/nest/iface.c
+++ b/nest/iface.c
@@ -32,11 +32,14 @@
 #include "lib/resource.h"
 #include "lib/string.h"
 #include "conf/conf.h"
+#include "sysdep/unix/krt.h"
 
 static pool *if_pool;
 
 list iface_list;
 
+static void if_recalc_preferred(struct iface *i);
+
 /**
  * ifa_dump - dump interface address
  * @a: interface address descriptor
@@ -183,6 +186,7 @@ if_send_notify(struct proto *p, unsigned c, struct iface *i)
 	    (c & IF_CHANGE_DOWN) ? "goes down" :
 	    (c & IF_CHANGE_MTU) ? "changes MTU" :
 	    (c & IF_CHANGE_LINK) ? "changes link" :
+	    (c & IF_CHANGE_PREFERRED) ? "changes preferred address" :
 	    (c & IF_CHANGE_CREATE) ? "created" :
 	    "sends unknown event");
       p->if_notify(p, c, i);
@@ -211,20 +215,14 @@ if_notify_change(unsigned c, struct iface *i)
 
   if (c & IF_CHANGE_DOWN)
     WALK_LIST(a, i->addrs)
-      {
-	a->flags = (i->flags & ~IA_FLAGS) | (a->flags & IA_FLAGS);
-	ifa_notify_change_(IF_CHANGE_DOWN, a);
-      }
+      ifa_notify_change_(IF_CHANGE_DOWN, a);
 
   WALK_LIST(p, proto_list)
     if_send_notify(p, c, i);
 
   if (c & IF_CHANGE_UP)
     WALK_LIST(a, i->addrs)
-      {
-	a->flags = (i->flags & ~IA_FLAGS) | (a->flags & IA_FLAGS);
-	ifa_notify_change_(IF_CHANGE_UP, a);
-      }
+      ifa_notify_change_(IF_CHANGE_UP, a);
 
   if (c & IF_CHANGE_UP)
     neigh_if_up(i);
@@ -233,24 +231,23 @@ if_notify_change(unsigned c, struct iface *i)
     neigh_if_link(i);
 }
 
-static unsigned
-if_recalc_flags(struct iface *i, unsigned flags)
+static uint
+if_recalc_flags(struct iface *i UNUSED, uint flags)
 {
-  if ((flags & (IF_SHUTDOWN | IF_TMP_DOWN)) ||
-      !(flags & IF_ADMIN_UP) ||
-      !i->addr)
-    flags &= ~IF_UP;
-  else
+  if ((flags & IF_ADMIN_UP) && !(flags & (IF_SHUTDOWN | IF_TMP_DOWN)))
     flags |= IF_UP;
+  else
+    flags &= ~IF_UP;
+
   return flags;
 }
 
 static void
-if_change_flags(struct iface *i, unsigned flags)
+if_change_flags(struct iface *i, uint flags)
 {
-  unsigned of = i->flags;
-
+  uint of = i->flags;
   i->flags = if_recalc_flags(i, flags);
+
   if ((i->flags ^ of) & IF_UP)
     if_notify_change((i->flags & IF_UP) ? IF_CHANGE_UP : IF_CHANGE_DOWN, i);
 }
@@ -298,7 +295,6 @@ if_update(struct iface *new)
   WALK_LIST(i, iface_list)
     if (!strcmp(new->name, i->name))
       {
-	new->addr = i->addr;
 	new->flags = if_recalc_flags(new, new->flags);
 	c = if_what_changed(i, new);
 	if (c & IF_CHANGE_TOO_MUCH)	/* Changed a lot, convert it to down/up */
@@ -306,10 +302,13 @@ if_update(struct iface *new)
 	    DBG("Interface %s changed too much -- forcing down/up transition\n", i->name);
 	    if_change_flags(i, i->flags | IF_TMP_DOWN);
 	    rem_node(&i->n);
-	    new->addr = i->addr;
+	    new->addr4 = i->addr4;
+	    new->addr6 = i->addr6;
+	    new->llv6 = i->llv6;
+	    new->sysdep = i->sysdep;
 	    memcpy(&new->addrs, &i->addrs, sizeof(i->addrs));
 	    memcpy(i, new, sizeof(*i));
-	    i->flags &= ~IF_UP; /* IF_TMP_DOWN will be added later */
+	    i->flags &= ~IF_UP; 	/* IF_TMP_DOWN will be added later */
 	    goto newif;
 	  }
 
@@ -340,13 +339,16 @@ if_start_update(void)
     {
       i->flags &= ~IF_UPDATED;
       WALK_LIST(a, i->addrs)
-	a->flags &= ~IF_UPDATED;
+	a->flags &= ~IA_UPDATED;
     }
 }
 
 void
 if_end_partial_update(struct iface *i)
 {
+  if (i->flags & IF_NEEDS_RECALC)
+    if_recalc_preferred(i);
+
   if (i->flags & IF_TMP_DOWN)
     if_change_flags(i, i->flags & ~IF_TMP_DOWN);
 }
@@ -364,7 +366,7 @@ if_end_update(void)
       else
 	{
 	  WALK_LIST_DELSAFE(a, b, i->addrs)
-	    if (!(a->flags & IF_UPDATED))
+	    if (!(a->flags & IA_UPDATED))
 	      ifa_delete(a);
 	  if_end_partial_update(i);
 	}
@@ -461,40 +463,99 @@ if_get_by_name(char *name)
   return i;
 }
 
-struct ifa *kif_choose_primary(struct iface *i);
+static inline void
+if_set_preferred(struct ifa **pos, struct ifa *new)
+{
+  if (*pos)
+    (*pos)->flags &= ~IA_PRIMARY;
+  if (new)
+    new->flags |= IA_PRIMARY;
 
-static int
-ifa_recalc_primary(struct iface *i)
+  *pos = new;
+}
+
+static void
+if_recalc_preferred(struct iface *i)
 {
-  struct ifa *a = kif_choose_primary(i);
+  /*
+   * Preferred address selection priority:
+   * 1) Address configured in Device protocol
+   * 2) Sysdep IPv4 address (BSD)
+   * 3) Old preferred address
+   * 4) First address in list
+   */
 
-  if (a == i->addr)
-    return 0;
+  struct kif_iface_config *ic = kif_get_iface_config(i);
+  struct ifa *a4 = i->addr4, *a6 = i->addr6, *ll = i->llv6;
+  ip_addr pref_v4 = ic->pref_v4;
+  uint change = 0;
+
+  if (kif_update_sysdep_addr(i))
+    change |= IF_CHANGE_SYSDEP;
 
-  if (i->addr)
-    i->addr->flags &= ~IA_PRIMARY;
+  /* BSD sysdep address */
+  if (ipa_zero(pref_v4) && ip4_nonzero(i->sysdep))
+    pref_v4 = ipa_from_ip4(i->sysdep);
 
-  if (a)
+  struct ifa *a;
+  WALK_LIST(a, i->addrs)
     {
-      a->flags |= IA_PRIMARY;
-      rem_node(&a->n);
-      add_head(&i->addrs, &a->n);
+      /* Secondary address is never selected */
+      if (a->flags & IA_SECONDARY)
+	continue;
+
+      if (ipa_is_ip4(a->ip)) {
+	if (!a4 || ipa_equal(a->ip, pref_v4))
+	  a4 = a;
+      } else if (!ipa_is_link_local(a->ip)) {
+	if (!a6 || ipa_equal(a->ip, ic->pref_v6))
+	  a6 = a;
+      } else {
+	if (!ll || ipa_equal(a->ip, ic->pref_ll))
+	  ll = a;
+      }
     }
 
-  i->addr = a;
-  return 1;
+  if (a4 != i->addr4)
+  {
+    if_set_preferred(&i->addr4, a4);
+    change |= IF_CHANGE_ADDR4;
+  }
+
+  if (a6 != i->addr6)
+  {
+    if_set_preferred(&i->addr6, a6);
+    change |= IF_CHANGE_ADDR6;
+  }
+
+  if (ll != i->llv6)
+  {
+    if_set_preferred(&i->llv6, ll);
+    change |= IF_CHANGE_LLV6;
+  }
+
+  i->flags &= ~IF_NEEDS_RECALC;
+
+  /*
+   * FIXME: There should be proper notification instead of iface restart:
+   * if_notify_change(change, i)
+   */
+  if (change)
+    if_change_flags(i, i->flags | IF_TMP_DOWN);
 }
 
 void
-ifa_recalc_all_primary_addresses(void)
+if_recalc_all_preferred_addresses(void)
 {
   struct iface *i;
 
   WALK_LIST(i, iface_list)
-    {
-      if (ifa_recalc_primary(i))
-	if_change_flags(i, i->flags | IF_TMP_DOWN);
-    }
+  {
+    if_recalc_preferred(i);
+
+    if (i->flags & IF_TMP_DOWN)
+      if_change_flags(i, i->flags & ~IF_TMP_DOWN);
+  }
 }
 
 static inline int
@@ -526,7 +587,7 @@ ifa_update(struct ifa *a)
 	    b->scope == a->scope &&
 	    !((b->flags ^ a->flags) & IA_PEER))
 	  {
-	    b->flags |= IF_UPDATED;
+	    b->flags |= IA_UPDATED;
 	    return b;
 	  }
 	ifa_delete(b);
@@ -534,15 +595,15 @@ ifa_update(struct ifa *a)
       }
 
   if ((a->prefix.type == NET_IP4) && (i->flags & IF_BROADCAST) && ipa_zero(a->brd))
-    log(L_ERR "Missing broadcast address for interface %s", i->name);
+    log(L_WARN "Missing broadcast address for interface %s", i->name);
 
   b = mb_alloc(if_pool, sizeof(struct ifa));
   memcpy(b, a, sizeof(struct ifa));
   add_tail(&i->addrs, &b->n);
-  b->flags = (i->flags & ~IA_FLAGS) | (a->flags & IA_FLAGS);
-  if (ifa_recalc_primary(i))
-    if_change_flags(i, i->flags | IF_TMP_DOWN);
-  if (b->flags & IF_UP)
+  b->flags |= IA_UPDATED;
+
+  i->flags |= IF_NEEDS_RECALC;
+  if (i->flags & IF_UP)
     ifa_notify_change(IF_CHANGE_CREATE | IF_CHANGE_UP, b);
   return b;
 }
@@ -565,16 +626,24 @@ ifa_delete(struct ifa *a)
     if (ifa_same(b, a))
       {
 	rem_node(&b->n);
-	if (b->flags & IF_UP)
-	  {
-	    b->flags &= ~IF_UP;
-	    ifa_notify_change(IF_CHANGE_DOWN, b);
-	  }
+
 	if (b->flags & IA_PRIMARY)
 	  {
-	    if_change_flags(i, i->flags | IF_TMP_DOWN);
-	    ifa_recalc_primary(i);
+	    /*
+	     * We unlink deleted preferred address and mark for recalculation.
+	     * FIXME: This could break if we make iface scan non-atomic, as
+	     * protocols still could use the freed address until they get
+	     * if_notify from preferred route recalculation.
+	     */
+	    if (b == i->addr4) i->addr4 = NULL;
+	    if (b == i->addr6) i->addr6 = NULL;
+	    if (b == i->llv6) i->llv6 = NULL;
+	    i->flags |= IF_NEEDS_RECALC;
 	  }
+
+	if (i->flags & IF_UP)
+	  ifa_notify_change(IF_CHANGE_DOWN, b);
+
 	mb_free(b);
 	return;
       }
@@ -741,16 +810,17 @@ iface_patts_equal(list *a, list *b, int (*comp)(struct iface_patt *, struct ifac
 static void
 if_show_addr(struct ifa *a)
 {
-  byte opp[IPA_MAX_TEXT_LENGTH + 16];
+  byte *flg, opp[IPA_MAX_TEXT_LENGTH + 16];
+
+  flg = (a->flags & IA_PRIMARY) ? "Preferred, " : (a->flags & IA_SECONDARY) ? "Secondary, " : "";
 
   if (ipa_nonzero(a->opposite))
-    bsprintf(opp, ", opposite %I", a->opposite);
+    bsprintf(opp, "opposite %I, ", a->opposite);
   else
     opp[0] = 0;
-  cli_msg(-1003, "\t%I/%d (%s%s, scope %s)",
-	  a->ip, a->prefix.pxlen,
-	  (a->flags & IA_PRIMARY) ? "Primary" : (a->flags & IA_SECONDARY) ? "Secondary" : "Unselected",
-	  opp, ip_scope_text(a->scope));
+
+  cli_msg(-1003, "\t%I/%d (%s%sscope %s)",
+	  a->ip, a->prefix.pxlen, flg, opp, ip_scope_text(a->scope));
 }
 
 void
@@ -765,7 +835,7 @@ if_show(void)
       if (i->flags & IF_SHUTDOWN)
 	continue;
 
-      cli_msg(-1001, "%s %s (index=%d)", i->name, (i->flags & IF_UP) ? "up" : "DOWN", i->index);
+      cli_msg(-1001, "%s %s (index=%d)", i->name, (i->flags & IF_UP) ? "Up" : "Down", i->index);
       if (!(i->flags & IF_MULTIACCESS))
 	type = "PtP";
       else
@@ -779,10 +849,13 @@ if_show(void)
 	      (i->flags & IF_LOOPBACK) ? " Loopback" : "",
 	      (i->flags & IF_IGNORE) ? " Ignored" : "",
 	      i->mtu);
-      if (i->addr)
-	if_show_addr(i->addr);
+
+      WALK_LIST(a, i->addrs)
+	if (a->prefix.type == NET_IP4)
+	  if_show_addr(a);
+
       WALK_LIST(a, i->addrs)
-	if (a != i->addr)
+	if (a->prefix.type == NET_IP6)
 	  if_show_addr(a);
     }
   cli_msg(0, "");
@@ -792,16 +865,25 @@ void
 if_show_summary(void)
 {
   struct iface *i;
-  byte addr[IPA_MAX_TEXT_LENGTH + 16];
 
-  cli_msg(-2005, "interface state address");
+  cli_msg(-2005,  "%-10s %-6s %-18s %s", "Interface", "State", "IPv4 address", "IPv6 address");
   WALK_LIST(i, iface_list)
     {
-      if (i->addr)
-	bsprintf(addr, "%I/%d", i->addr->ip, i->addr->prefix.pxlen);
+      byte a4[IPA_MAX_TEXT_LENGTH + 17];
+      byte a6[IPA_MAX_TEXT_LENGTH + 17];
+
+      if (i->addr4)
+	bsprintf(a4, "%I/%d", i->addr4->ip, i->addr4->prefix.pxlen);
       else
-	addr[0] = 0;
-      cli_msg(-1005, "%-9s %-5s %s", i->name, (i->flags & IF_UP) ? "up" : "DOWN", addr);
+	a4[0] = 0;
+
+      if (i->addr6)
+	bsprintf(a6, "%I/%d", i->addr6->ip, i->addr6->prefix.pxlen);
+      else
+	a6[0] = 0;
+
+      cli_msg(-1005, "%-10s %-6s %-18s %s",
+	      i->name, (i->flags & IF_UP) ? "Up" : "Down", a4, a6);
     }
   cli_msg(0, "");
 }
diff --git a/nest/iface.h b/nest/iface.h
index de5070d6..59b1253c 100644
--- a/nest/iface.h
+++ b/nest/iface.h
@@ -35,11 +35,14 @@ struct iface {
   unsigned mtu;
   unsigned index;			/* OS-dependent interface index */
   list addrs;				/* Addresses assigned to this interface */
-  struct ifa *addr;			/* Primary address */
+  struct ifa *addr4;			/* Primary address for IPv4 */
+  struct ifa *addr6;			/* Primary address for IPv6 */
+  struct ifa *llv6;			/* Primary link-local address for IPv6 */
+  ip4_addr sysdep;			/* Arbitrary IPv4 address for internal sysdep use */
   list neighbors;			/* All neighbors on this interface */
 };
 
-#define IF_UP 1				/* IF_ADMIN_UP and IP address known */
+#define IF_UP 1				/* Currently just IF_ADMIN_UP */
 #define IF_MULTIACCESS 2
 #define IF_BROADCAST 4
 #define IF_MULTICAST 8
@@ -70,7 +73,10 @@ struct iface {
 
 #define IF_JUST_CREATED 0x10000000	/* Send creation event as soon as possible */
 #define IF_TMP_DOWN 0x20000000		/* Temporary shutdown due to interface reconfiguration */
-#define IF_UPDATED 0x40000000		/* Touched in last scan */
+#define IF_UPDATED 0x40000000		/* Iface touched in last scan */
+#define IF_NEEDS_RECALC	0x80000000	/* Preferred address recalculation is needed */
+
+#define IA_UPDATED IF_UPDATED		/* Address touched in last scan */
 
 /* Interface change events */
 
@@ -79,8 +85,14 @@ struct iface {
 #define IF_CHANGE_MTU 4
 #define IF_CHANGE_CREATE 8		/* Seen this interface for the first time */
 #define IF_CHANGE_LINK 0x10
+#define IF_CHANGE_ADDR4	0x100		/* Change of iface->addr4 */
+#define IF_CHANGE_ADDR6	0x200		/* ... */
+#define IF_CHANGE_LLV6 0x400
+#define IF_CHANGE_SYSDEP 0x800
 #define IF_CHANGE_TOO_MUCH 0x40000000	/* Used internally */
 
+#define IF_CHANGE_PREFERRED (IF_CHANGE_ADDR4 | IF_CHANGE_ADDR6 | IF_CHANGE_LLV6)
+
 void if_init(void);
 void if_dump(struct iface *);
 void if_dump_all(void);
@@ -99,7 +111,7 @@ void if_feed_baby(struct proto *);
 struct iface *if_find_by_index(unsigned);
 struct iface *if_find_by_name(char *);
 struct iface *if_get_by_name(char *);
-void ifa_recalc_all_primary_addresses(void);
+void if_recalc_all_preferred_addresses(void);
 
 
 /* The Neighbor Cache */
diff --git a/nest/rt-dev.c b/nest/rt-dev.c
index 9993da24..b3d5bf97 100644
--- a/nest/rt-dev.c
+++ b/nest/rt-dev.c
@@ -33,7 +33,7 @@ dev_ifa_notify(struct proto *P, uint flags, struct ifa *ad)
   struct channel *c;
 
   if (!EMPTY_LIST(cf->iface_list) &&
-      !iface_patt_find(&cf->iface_list, ad->iface, ad->iface->addr))
+      !iface_patt_find(&cf->iface_list, ad->iface, ad))
     /* Empty list is automatically treated as "*" */
     return;