From f73fe7b75dd7a40e0e9bca3b7414d0b43e1bd1ef Mon Sep 17 00:00:00 2001
From: Sososhas <1248756005hfh@gmail.com>
Date: Thu, 19 Oct 2023 23:39:24 +0300
Subject: [PATCH] isisd: added l1 to l2 distibution

added adding prefixes with the best metric from the level-1 db
to the level-2 db on l1_l2 end system

Signed-off-by: Sososhas <1248756005hfh@gmail.com>
---
 isisd/isis_lsp.c | 68 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 61 insertions(+), 7 deletions(-)

diff --git a/isisd/isis_lsp.c b/isisd/isis_lsp.c
index 1b3491f5d38e..ffb7174b6080 100644
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -1317,6 +1317,15 @@ static void lsp_build(struct isis_lsp *lsp, struct isis_area *area)
 					 false, false, false);
 	}
 
+	                 struct isis_adjacency* adj;
+                bool flag = false;
+                for (ALL_LIST_ELEMENTS_RO(area->adjacency_list, node, adj)) {
+                        if (adj->level == IS_LEVEL_2)
+                                flag = true;
+                }
+
+
+
 	struct isis_circuit *circuit;
 	for (ALL_LIST_ELEMENTS_RO(area->circuit_list, node, circuit)) {
 		if (!circuit->interface)
@@ -1348,6 +1357,7 @@ static void lsp_build(struct isis_lsp *lsp, struct isis_area *area)
 					  ? circuit->metric[level - 1]
 					  : circuit->te_metric[level - 1];
 
+
 		if (circuit->ip_router && circuit->ip_addrs->count > 0) {
 			lsp_debug(
 				"ISIS (%s): Circuit has IPv4 active, adding respective TLVs.",
@@ -1360,14 +1370,58 @@ static void lsp_build(struct isis_lsp *lsp, struct isis_area *area)
 							      metric);
 		}
 
-		if (circuit->ipv6_router && circuit->ipv6_non_link->count > 0) {
-			struct listnode *ipnode;
-			struct prefix_ipv6 *ipv6;
 
-			for (ALL_LIST_ELEMENTS_RO(circuit->ipv6_non_link,
-						  ipnode, ipv6))
-				lsp_build_internal_reach_ipv6(lsp, area, ipv6,
-							      metric);
+		if (circuit->ipv6_router && circuit->ipv6_non_link->count > 0) {
+                        struct listnode *ipnode;
+                        struct prefix_ipv6 *ipv6;
+                        char prefixbuf[PREFIX2STR_BUFFER];
+                        for (ALL_LIST_ELEMENTS_RO(circuit->ipv6_non_link,
+                                                  ipnode, ipv6)) {
+                                lsp_build_internal_reach_ipv6(lsp, area, ipv6,
+                                                              metric);
+                        }
+                }
+                
+                if(flag && (lsp->level == IS_LEVEL_2) && (area->is_type == 3) && (lsp->hdr.lsp_bits != LSPBIT_ATT)) {
+                	struct isis_lsp* lsp_tmp;
+               		struct lspdb_head *head_tmp = &area->lspdb[0];
+                        if(head_tmp) {
+                                frr_each (lspdb, head_tmp, lsp_tmp) {
+                                        if (strcmp(lsp->tlvs->hostname, lsp_tmp->tlvs->hostname) != 0) {
+                                                for (struct isis_item* i = lsp_tmp->tlvs->extended_ip_reach.head; i; i = i->next){
+                                                        struct isis_extended_ip_reach *r = (struct isis_extended_ip_reach *)i;
+                                                        int count = 0;
+                                                        for (struct isis_item* l = lsp->tlvs->extended_ip_reach.head; l; l = l->next) {
+                                                                struct isis_extended_ip_reach *rt = (struct isis_extended_ip_reach *)l;
+                                                                if(r->prefix.prefix.s_addr == rt->prefix.prefix.s_addr) {
+									if ((r->metric > rt->metric) || (r->metric == rt->metric)) 
+                                                                                count++;
+                                                                        break;
+                                                                }
+                                                        }
+                                                        if (count == 0) {
+                                                                lsp_build_internal_reach_ipv4(lsp, area, &r->prefix , r->metric);
+							}
+                                                }
+                                                for (struct isis_item* i = lsp_tmp->tlvs->ipv6_reach.head; i; i = i->next){
+                                                        struct isis_ipv6_reach *r = (struct isis_ipv6_reach *)i;
+                                                        int count = 0;
+                                                        for (struct isis_item* l = lsp->tlvs->ipv6_reach.head; l; l = l->next) {
+                                                                struct isis_ipv6_reach *rt = (struct isis_ipv6_reach *)l;
+                                                                char prefixbuf_1[PREFIX2STR_BUFFER];
+                                                                char prefixbuf_2[PREFIX2STR_BUFFER];
+                                                                if(strcmp(prefix2str(&r->prefix, prefixbuf_1, sizeof(prefixbuf_1)), prefix2str(&rt->prefix, prefixbuf_2, sizeof(prefixbuf_2))) == 0){
+                                                                       if ((r->metric > rt->metric) || (r->metric == rt->metric)) 
+                                                                                count++;
+                                                                        break;
+                                                                }
+                                                        }
+                                                        if (count == 0)
+                                                                lsp_build_internal_reach_ipv6(lsp, area, &r->prefix, r->metric);
+                                                }
+                                        }
+                		}
+			}
 		}
 
 		switch (circuit->circ_type) {