bgpd: Track link bandwidth during multipath calc

During multipath update, track the cumulative link bandwidth
as well as update flags appropriately.

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Reviewed-by:   Donald Sharp <sharpd@cumulusnetworks.com>
Reviewed-by:   Don Slice <dslice@cumulusnetworks.com>

diff --git a/bgpd/bgp_mpath.c b/bgpd/bgp_mpath.c
index fb0613ebb7635924b677614bc0ce79021902c03e..4fe57b9bdc265db6779c11ceb560d1acd9260996 100644 (file)
--- a/bgpd/bgp_mpath.c
+++ b/bgpd/bgp_mpath.c
@@ -401,6 +401,35 @@ static void bgp_path_info_mpath_count_set(struct bgp_path_info *path,
        mpath->mp_count = count;
 }
 
+/*
+ * bgp_path_info_mpath_lb_update
+ *
+ * Update cumulative info related to link-bandwidth
+ */
+static void bgp_path_info_mpath_lb_update(struct bgp_path_info *path, bool set,
+                                         bool all_paths_lb, uint64_t cum_bw)
+{
+       struct bgp_path_info_mpath *mpath;
+
+       if ((mpath = path->mpath) == NULL) {
+               if (!set)
+                       return;
+               mpath = bgp_path_info_mpath_get(path);
+               if (!mpath)
+                       return;
+       }
+       if (set) {
+               if (all_paths_lb)
+                       SET_FLAG(mpath->mp_flags, BGP_MP_LB_ALL);
+               else
+                       UNSET_FLAG(mpath->mp_flags, BGP_MP_LB_ALL);
+               mpath->cum_bw = cum_bw;
+       } else {
+               mpath->mp_flags = 0;
+               mpath->cum_bw = 0;
+       }
+}
+
 /*
  * bgp_path_info_mpath_attr
  *
@@ -444,10 +473,13 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
                                struct bgp_maxpaths_cfg *mpath_cfg)
 {
        uint16_t maxpaths, mpath_count, old_mpath_count;
+       uint32_t bwval;
+       uint64_t cum_bw;
        struct listnode *mp_node, *mp_next_node;
        struct bgp_path_info *cur_mpath, *new_mpath, *next_mpath, *prev_mpath;
        int mpath_changed, debug;
        char nh_buf[2][INET6_ADDRSTRLEN];
+       bool all_paths_lb;
        char path_buf[PATH_ADDPATH_STR_BUFFER];
 
        mpath_changed = 0;
@@ -455,6 +487,7 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
        mpath_count = 0;
        cur_mpath = NULL;
        old_mpath_count = 0;
+       cum_bw = 0;
        prev_mpath = new_best;
        mp_node = listhead(mp_list);
        debug = bgp_debug_bestpath(rn);
@@ -472,6 +505,7 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
                cur_mpath = bgp_path_info_mpath_first(old_best);
                old_mpath_count = bgp_path_info_mpath_count(old_best);
                bgp_path_info_mpath_count_set(old_best, 0);
+               bgp_path_info_mpath_lb_update(old_best, false, false, 0);
                bgp_path_info_mpath_dequeue(old_best);
        }
 
@@ -492,6 +526,7 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
         * Note that new_best might be somewhere in the mp_list, so we need
         * to skip over it
         */
+       all_paths_lb = true; /* We'll reset if any path doesn't have LB. */
        while (mp_node || cur_mpath) {
                struct bgp_path_info *tmp_info;
 
@@ -530,6 +565,11 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
                                                            cur_mpath);
                                prev_mpath = cur_mpath;
                                mpath_count++;
+                               if (ecommunity_linkbw_present(
+                                       cur_mpath->attr->ecommunity, &bwval))
+                                       cum_bw += bwval;
+                               else
+                                       all_paths_lb = false;
                                if (debug) {
                                        bgp_path_info_path_with_addpath_rx_str(
                                                cur_mpath, path_buf);
@@ -617,6 +657,11 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
                                prev_mpath = new_mpath;
                                mpath_changed = 1;
                                mpath_count++;
+                               if (ecommunity_linkbw_present(
+                                       new_mpath->attr->ecommunity, &bwval))
+                                       cum_bw += bwval;
+                               else
+                                       all_paths_lb = false;
                                if (debug) {
                                        bgp_path_info_path_with_addpath_rx_str(
                                                new_mpath, path_buf);
@@ -636,13 +681,24 @@ void bgp_path_info_mpath_update(struct bgp_node *rn,
        }
 
        if (new_best) {
+               bgp_path_info_mpath_count_set(new_best, mpath_count - 1);
+               if (mpath_count <= 1 ||
+                   !ecommunity_linkbw_present(
+                       new_best->attr->ecommunity, &bwval))
+                       all_paths_lb = false;
+               else
+                       cum_bw += bwval;
+               bgp_path_info_mpath_lb_update(new_best, true,
+                                             all_paths_lb, cum_bw);
+
                if (debug)
                        zlog_debug(
-                               "%pRN: New mpath count (incl newbest) %d mpath-change %s",
+                               "%pRN: New mpath count (incl newbest) %d mpath-change %s"
+                               " all_paths_lb %d cum_bw u%" PRIu64,
                                rn, mpath_count,
-                               mpath_changed ? "YES" : "NO");
+                               mpath_changed ? "YES" : "NO",
+                               all_paths_lb, cum_bw);
 
-               bgp_path_info_mpath_count_set(new_best, mpath_count - 1);
                if (mpath_changed
                    || (bgp_path_info_mpath_count(new_best) != old_mpath_count))
                        SET_FLAG(new_best->flags, BGP_PATH_MULTIPATH_CHG);