*: conform with COMMUNITY.md formatting rules, via 'make indent'

[mirror_frr.git] / bgpd / bgp_packet.c

diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
index eed5fdc65d2362b0c68862e4d1ad949095cfc706..cb702d80d1f1fd7f8afe97db90ece96fb56098ce 100644 (file)
--- a/bgpd/bgp_packet.c
+++ b/bgpd/bgp_packet.c
@@ -545,19 +545,26 @@ void bgp_open_send(struct peer *peer)
        bgp_writes_on(peer);
 }
 
-/* This is only for sending NOTIFICATION message to neighbor. */
+/*
+ * Writes NOTIFICATION message directly to a peer socket without waiting for
+ * the I/O thread.
+ *
+ * There must be exactly one stream on the peer->obuf FIFO, and the data within
+ * this stream must match the format of a BGP NOTIFICATION message.
+ * Transmission is best-effort.
+ *
+ * @requires peer->io_mtx
+ * @param peer
+ * @return 0
+ */
 static int bgp_write_notify(struct peer *peer)
 {
        int ret, val;
        u_char type;
        struct stream *s;
 
-       pthread_mutex_lock(&peer->io_mtx);
-       {
-               /* There should be at least one packet. */
-               s = stream_fifo_pop(peer->obuf);
-       }
-       pthread_mutex_unlock(&peer->io_mtx);
+       /* There should be at least one packet. */
+       s = stream_fifo_pop(peer->obuf);
 
        if (!s)
                return 0;
@@ -622,6 +629,14 @@ static int bgp_write_notify(struct peer *peer)
  * This function attempts to write the packet from the thread it is called
  * from, to ensure the packet gets out ASAP.
  *
+ * This function may be called from multiple threads. Since the function
+ * modifies I/O buffer(s) in the peer, these are locked for the duration of the
+ * call to prevent tampering from other threads.
+ *
+ * Delivery of the NOTIFICATION is attempted once and is best-effort. After
+ * return, the peer structure *must* be reset; no assumptions about session
+ * state are valid.
+ *
  * @param peer
  * @param code      BGP error code
  * @param sub_code  BGP error subcode
@@ -634,6 +649,10 @@ void bgp_notify_send_with_data(struct peer *peer, u_char code, u_char sub_code,
        struct stream *s;
        int length;
 
+       /* Lock I/O mutex to prevent other threads from pushing packets */
+       pthread_mutex_lock(&peer->io_mtx);
+       /* ============================================== */
+
        /* Allocate new stream. */
        s = stream_new(BGP_MAX_PACKET_SIZE);
 
@@ -651,20 +670,8 @@ void bgp_notify_send_with_data(struct peer *peer, u_char code, u_char sub_code,
        /* Set BGP packet length. */
        length = bgp_packet_set_size(s);
 
-       /*
-        * Turn off keepalive generation for peer. This is necessary because
-        * otherwise between the time we wipe the output buffer and the time we
-        * push the NOTIFY onto it, the KA generation thread could have pushed
-        * a KEEPALIVE in the middle.
-        */
-       bgp_keepalives_off(peer);
-
        /* wipe output buffer */
-       pthread_mutex_lock(&peer->io_mtx);
-       {
-               stream_fifo_clean(peer->obuf);
-       }
-       pthread_mutex_unlock(&peer->io_mtx);
+       stream_fifo_clean(peer->obuf);
 
        /*
         * If possible, store last packet for debugging purposes. This check is
@@ -728,9 +735,12 @@ void bgp_notify_send_with_data(struct peer *peer, u_char code, u_char sub_code,
                peer->last_reset = PEER_DOWN_NOTIFY_SEND;
 
        /* Add packet to peer's output queue */
-       bgp_packet_add(peer, s);
+       stream_fifo_push(peer->obuf, s);
 
        bgp_write_notify(peer);
+
+       /* ============================================== */
+       pthread_mutex_unlock(&peer->io_mtx);
 }
 
 /*
@@ -1563,9 +1573,8 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size)
         * Non-MP IPv4/Unicast EoR is a completely empty UPDATE
         * and MP EoR should have only an empty MP_UNREACH
         */
-       if ((!update_len && !withdraw_len &&
-            nlris[NLRI_MP_UPDATE].length == 0) ||
-           (attr_parse_ret == BGP_ATTR_PARSE_EOR)) {
+       if ((!update_len && !withdraw_len && nlris[NLRI_MP_UPDATE].length == 0)
+           || (attr_parse_ret == BGP_ATTR_PARSE_EOR)) {
                afi_t afi = 0;
                safi_t safi;