Allowed optimized exporting of a subprefix tree

Added an option for export filter to allow for prefiltering based on the
prefix. Routes outside the given prefix are completely ignored. Config
is simple:

	export in <net> <filter>;

3 files changed, 15 insertions, 0 deletions

diff --git a/proto/pipe/config.Y b/proto/pipe/config.Y
index c869de9f..0990168e 100644
--- a/proto/pipe/config.Y
+++ b/proto/pipe/config.Y
@@ -41,6 +41,12 @@ pipe_proto:
    pipe_proto_start '{'
  | pipe_proto proto_item ';'
  | pipe_proto channel_item_ ';'
+ | pipe_proto IMPORT IN net_any imexport ';' {
+    if (this_channel->net_type && ($4->type != this_channel->net_type))
+      cf_error("Incompatible export prefilter type");
+    PIPE_CFG->in_subprefix = $4;
+    this_channel->in_filter = $5;
+  }
  | pipe_proto PEER TABLE rtable ';' { PIPE_CFG->peer = $4; }
  | pipe_proto MAX GENERATION expr ';' {
     if (($4 < 1) || ($4 > 254)) cf_error("Max generation must be in range 1..254, got %u", $4);
diff --git a/proto/pipe/pipe.c b/proto/pipe/pipe.c
index d12e6731..351db36b 100644
--- a/proto/pipe/pipe.c
+++ b/proto/pipe/pipe.c
@@ -123,6 +123,12 @@ pipe_postconfig(struct proto_config *CF)
   if (cc->table->addr_type != cf->peer->addr_type)
     cf_error("Primary table and peer table must have the same type");
 
+  if (cc->out_subprefix && (cc->table->addr_type != cc->out_subprefix->type))
+    cf_error("Export subprefix must match table type");
+
+  if (cf->in_subprefix && (cc->table->addr_type != cf->in_subprefix->type))
+    cf_error("Import subprefix must match table type");
+
   if (cc->rx_limit.action)
     cf_error("Pipe protocol does not support receive limits");
 
@@ -142,6 +148,7 @@ pipe_configure_channels(struct pipe_proto *p, struct pipe_config *cf)
     .channel = cc->channel,
     .table = cc->table,
     .out_filter = cc->out_filter,
+    .out_subprefix = cc->out_subprefix,
     .in_limit = cc->in_limit,
     .ra_mode = RA_ANY,
     .debug = cc->debug,
@@ -153,6 +160,7 @@ pipe_configure_channels(struct pipe_proto *p, struct pipe_config *cf)
     .channel = cc->channel,
     .table = cf->peer,
     .out_filter = cc->in_filter,
+    .out_subprefix = cf->in_subprefix,
     .in_limit = cc->out_limit,
     .ra_mode = RA_ANY,
     .debug = cc->debug,
diff --git a/proto/pipe/pipe.h b/proto/pipe/pipe.h
index 60c857eb..a6534e1c 100644
--- a/proto/pipe/pipe.h
+++ b/proto/pipe/pipe.h
@@ -12,6 +12,7 @@
 struct pipe_config {
   struct proto_config c;
   struct rtable_config *peer;		/* Table we're connected to */
+  const net_addr *in_subprefix;
   u8 max_generation;
 };