[PATCH] babel: Initialise objects from slab completely

[Toke Høiland-Jørgensen]

The babel protocol code was initialising objects returned from the slab
allocator by assigning to each of the struct members individually, but
wasn't touching the NODE member while doing so. This leads to warnings on
debug builds since commit:

baac7009063d ("List expensive check.")

So let's change the babel code to make sure we also zero-initialise the
list node. For the packet parser, just move the existing memset() out of
babel_read_tlv() and in all other places, use struct assignment for
initialising members, which is idiomatic for Bird.

Signed-off-by: Toke Høiland-Jørgensen <toke at toke.dk>
---
 proto/babel/babel.c   | 31 ++++++++++++++++++-------------
 proto/babel/packets.c |  7 ++++---
 2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/proto/babel/babel.c b/proto/babel/babel.c
index 618abaa8a..588b29eaa 100644
--- a/proto/babel/babel.c
+++ b/proto/babel/babel.c
@@ -114,10 +114,12 @@ babel_get_source(struct babel_proto *p, struct babel_entry *e, u64 router_id)
     return s;
 
   s = sl_alloc(p->source_slab);
-  s->router_id = router_id;
-  s->expires = current_time() + BABEL_GARBAGE_INTERVAL;
-  s->seqno = 0;
-  s->metric = BABEL_INFINITY;
+  *s = (struct babel_source) {
+    .router_id = router_id,
+    .expires = current_time() + BABEL_GARBAGE_INTERVAL,
+    .seqno = 0,
+    .metric = BABEL_INFINITY,
+  };
   add_tail(&e->sources, NODE s);
 
   return s;
@@ -160,10 +162,10 @@ babel_get_route(struct babel_proto *p, struct babel_entry *e, struct babel_neigh
     return r;
 
   r = sl_alloc(p->route_slab);
-  memset(r, 0, sizeof(*r));
-
-  r->e = e;
-  r->neigh = nbr;
+  *r = (struct babel_route) {
+    .e = e,
+    .neigh = nbr
+  };
   add_tail(&e->routes, NODE r);
   add_tail(&nbr->routes, NODE &r->neigh_route);
 
@@ -326,11 +328,14 @@ babel_add_seqno_request(struct babel_proto *p, struct babel_entry *e,
   sr = sl_alloc(p->seqno_slab);
 
 found:
-  sr->router_id = router_id;
-  sr->seqno = seqno;
-  sr->hop_count = hop_count;
-  sr->count = 0;
-  sr->expires = current_time() + BABEL_SEQNO_REQUEST_EXPIRY;
+  *sr = (struct babel_seqno_request) {
+    .router_id = router_id,
+    .seqno = seqno,
+    .hop_count = hop_count,
+    .count = 0,
+    .expires = current_time() + BABEL_SEQNO_REQUEST_EXPIRY,
+  };
+
   babel_lock_neighbor(sr->nbr = nbr);
   add_tail(&e->requests, NODE sr);
 
diff --git a/proto/babel/packets.c b/proto/babel/packets.c
index d4ecf649d..98037ce69 100644
--- a/proto/babel/packets.c
+++ b/proto/babel/packets.c
@@ -1144,7 +1144,6 @@ babel_read_tlv(struct babel_tlv *hdr,
     return PARSE_ERROR;
 
   state->current_tlv_endpos = tlv_data[hdr->type].min_length;
-  memset(msg, 0, sizeof(*msg));
 
   int res = tlv_data[hdr->type].read_tlv(hdr, msg, state);
   if (res != PARSE_SUCCESS)
@@ -1278,7 +1277,7 @@ babel_send_unicast(union babel_msg *msg, struct babel_iface *ifa, ip_addr dest)
   struct babel_msg_node *msgn = sl_alloc(p->msg_slab);
   list queue;
 
-  msgn->msg = *msg;
+  *msgn = (struct babel_msg_node) { .msg = *msg };
   init_list(&queue);
   add_tail(&queue, NODE msgn);
   babel_write_queue(ifa, &queue);
@@ -1305,7 +1304,7 @@ babel_enqueue(union babel_msg *msg, struct babel_iface *ifa)
 {
   struct babel_proto *p = ifa->proto;
   struct babel_msg_node *msgn = sl_alloc(p->msg_slab);
-  msgn->msg = *msg;
+  *msgn = (struct babel_msg_node) { .msg = *msg };
   add_tail(&ifa->msg_queue, NODE msgn);
   babel_kick_queue(ifa);
 }
@@ -1387,6 +1386,8 @@ babel_process_packet(struct babel_pkt_header *pkt, int len,
     }
 
     msg = sl_alloc(p->msg_slab);
+    memset(msg, 0, sizeof(*msg));
+
     res = babel_read_tlv(tlv, &msg->msg, &state);
     if (res == PARSE_SUCCESS)
     {
-- 
2.29.2