isisd: Add CLI command to show SRv6 node info

Add a CLI command to print SRv6 capabilities, algorithms and MSDs
supported by the IS-IS nodes.

Example:

r1# show isis segment-routing srv6 node
Area FOO:
 IS-IS L1 SRv6-Nodes:

 IS-IS L2 SRv6-Nodes:

 System ID       Algorithm  SRH Max SL  SRH Max End Pop  SRH Max H.encaps  SRH Max End D
 -----------------------------------------------------------------------------------------
 1111.1111.1111  SPF        16          0                1                 2
 2222.2222.2222  SPF        16          0                1                 2

Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>

1 files changed, 86 insertions, 0 deletions

diff --git a/isisd/isis_srv6.c b/isisd/isis_srv6.c
index 564fd04285..1397ea4d0b 100644
--- a/isisd/isis_srv6.c
+++ b/isisd/isis_srv6.c
@@ -9,10 +9,95 @@
 
 #include <zebra.h>
 
+#include "termtable.h"
+
 #include "isisd/isisd.h"
+#include "isisd/isis_misc.h"
 #include "isisd/isis_srv6.h"
 
 /**
+ * Show Segment Routing over IPv6 (SRv6) Node.
+ *
+ * @param vty	VTY output
+ * @param area	IS-IS area
+ * @param level	IS-IS level
+ */
+static void show_node(struct vty *vty, struct isis_area *area, int level)
+{
+	struct isis_lsp *lsp;
+	struct ttable *tt;
+
+	vty_out(vty, " IS-IS %s SRv6-Nodes:\n\n", circuit_t2string(level));
+
+	/* Prepare table. */
+	tt = ttable_new(&ttable_styles[TTSTYLE_BLANK]);
+	ttable_add_row(
+		tt,
+		"System ID|Algorithm|SRH Max SL|SRH Max End Pop|SRH Max H.encaps|SRH Max End D");
+	tt->style.cell.rpad = 2;
+	tt->style.corner = '+';
+	ttable_restyle(tt);
+	ttable_rowseps(tt, 0, BOTTOM, true, '-');
+
+	frr_each (lspdb, &area->lspdb[level - 1], lsp) {
+		struct isis_router_cap *cap;
+
+		if (!lsp->tlvs)
+			continue;
+		cap = lsp->tlvs->router_cap;
+		if (!cap)
+			continue;
+
+		ttable_add_row(tt, "%pSY|%s|%u|%u|%u|%u", lsp->hdr.lsp_id,
+			       cap->algo[0] == SR_ALGORITHM_SPF ? "SPF"
+								: "S-SPF",
+			       cap->srv6_msd.max_seg_left_msd,
+			       cap->srv6_msd.max_end_pop_msd,
+			       cap->srv6_msd.max_h_encaps_msd,
+			       cap->srv6_msd.max_end_d_msd);
+	}
+
+	/* Dump the generated table. */
+	if (tt->nrows > 1) {
+		char *table;
+
+		table = ttable_dump(tt, "\n");
+		vty_out(vty, "%s\n", table);
+		XFREE(MTYPE_TMP, table);
+	}
+	ttable_del(tt);
+}
+
+DEFUN(show_srv6_node, show_srv6_node_cmd,
+      "show " PROTO_NAME " segment-routing srv6 node",
+      SHOW_STR
+      PROTO_HELP
+      "Segment-Routing\n"
+      "Segment-Routing over IPv6 (SRv6)\n"
+      "SRv6 node\n")
+{
+	struct listnode *node, *inode;
+	struct isis_area *area;
+	struct isis *isis;
+
+	for (ALL_LIST_ELEMENTS_RO(im->isis, inode, isis)) {
+		for (ALL_LIST_ELEMENTS_RO(isis->area_list, node, area)) {
+			vty_out(vty, "Area %s:\n",
+				area->area_tag ? area->area_tag : "null");
+			if (!area->srv6db.config.enabled) {
+				vty_out(vty, " SRv6 is disabled\n");
+				continue;
+			}
+			for (int level = ISIS_LEVEL1; level <= ISIS_LEVELS;
+			     level++)
+				show_node(vty, area, level);
+		}
+	}
+
+	return CMD_SUCCESS;
+}
+
+/**
  * IS-IS SRv6 initialization for given area.
  *
  * @param area	IS-IS area
@@ -56,6 +141,7 @@ void isis_srv6_area_term(struct isis_area *area)
  */
 void isis_srv6_init(void)
 {
+	install_element(VIEW_NODE, &show_srv6_node_cmd);
 }
 
 /**