From 1187627a1dded6a3673c0d43033f431f15cd1b8f Mon Sep 17 00:00:00 2001
From: "Ondrej Zajicek (work)" <santiago@crfreenet.org>
Date: Tue, 2 Jul 2019 16:30:36 +0200
Subject: [PATCH] Netlink: Do unified scan for both IPv4 and IPv6

Instead of separate scans for IPv4, IPv6 and MPLS, do one AF_UNSPEC scan.

This also avoids kernel issue when kernel reported IPv4 and IPv6 routes
during MPLS scan if MPLS is not active.
---
 sysdep/linux/netlink.c | 37 ++++++++-----------------------------
 1 file changed, 8 insertions(+), 29 deletions(-)

diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c
index d773743d..5a0b4d0c 100644
--- a/sysdep/linux/netlink.c
+++ b/sysdep/linux/netlink.c
@@ -1393,10 +1393,10 @@ krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old)
 }
 
 static int
-nl_mergable_route(struct nl_parse_state *s, net *net, struct krt_proto *p, uint priority, uint krt_type)
+nl_mergable_route(struct nl_parse_state *s, net *net, struct krt_proto *p, uint priority, uint krt_type, uint rtm_family)
 {
-  /* Route merging must be active */
-  if (!s->merge)
+  /* Route merging is used for IPv6 scans */
+  if (!s->scan || (rtm_family != AF_INET6))
     return 0;
 
   /* Saved and new route must have same network, proto/table, and priority */
@@ -1433,12 +1433,11 @@ nl_announce_route(struct nl_parse_state *s)
 }
 
 static inline void
-nl_parse_begin(struct nl_parse_state *s, int scan, int merge)
+nl_parse_begin(struct nl_parse_state *s, int scan)
 {
   memset(s, 0, sizeof (struct nl_parse_state));
   s->pool = nl_linpool;
   s->scan = scan;
-  s->merge = merge;
 }
 
 static inline void
@@ -1581,7 +1580,7 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
 
   net *net = net_get(p->p.main_channel->table, n);
 
-  if (s->net && !nl_mergable_route(s, net, p, priority, i->rtm_type))
+  if (s->net && !nl_mergable_route(s, net, p, priority, i->rtm_type, i->rtm_family))
     nl_announce_route(s);
 
   rta *ra = lp_allocz(s->pool, RTA_MAX_SIZE);
@@ -1814,34 +1813,14 @@ krt_do_scan(struct krt_proto *p UNUSED)	/* CONFIG_ALL_TABLES_AT_ONCE => p is NUL
   struct nlmsghdr *h;
   struct nl_parse_state s;
 
-  nl_parse_begin(&s, 1, 0);
-  nl_request_dump(AF_INET, RTM_GETROUTE);
+  nl_parse_begin(&s, 1);
+  nl_request_dump(AF_UNSPEC, RTM_GETROUTE);
   while (h = nl_get_scan())
     if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)
       nl_parse_route(&s, h);
     else
       log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
   nl_parse_end(&s);
-
-  nl_parse_begin(&s, 1, 1);
-  nl_request_dump(AF_INET6, RTM_GETROUTE);
-  while (h = nl_get_scan())
-    if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)
-      nl_parse_route(&s, h);
-    else
-      log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
-  nl_parse_end(&s);
-
-#ifdef HAVE_MPLS_KERNEL
-  nl_parse_begin(&s, 1, 1);
-  nl_request_dump(AF_MPLS, RTM_GETROUTE);
-  while (h = nl_get_scan())
-    if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)
-      nl_parse_route(&s, h);
-    else
-      log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
-  nl_parse_end(&s);
-#endif
 }
 
 /*
@@ -1861,7 +1840,7 @@ nl_async_msg(struct nlmsghdr *h)
     case RTM_NEWROUTE:
     case RTM_DELROUTE:
       DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);
-      nl_parse_begin(&s, 0, 0);
+      nl_parse_begin(&s, 0);
       nl_parse_route(&s, h);
       nl_parse_end(&s);
       break;