bgpd: UPDATE may be larger than 4096 if addpath is used

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>

diff --git a/bgpd/bgp_updgrp_packet.c b/bgpd/bgp_updgrp_packet.c
index d7a4a36986b17bd88f72c0216645a3aa21daab03..1a23a36e91a2bec06557ac1903f27226aa0606cb 100644 (file)
--- a/bgpd/bgp_updgrp_packet.c
+++ b/bgpd/bgp_updgrp_packet.c
@@ -700,6 +700,7 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
        int send_attr_printed = 0;
        int num_pfx = 0;
        int addpath_encode = 0;
+       int addpath_overhead = 0;
        u_int32_t addpath_tx_id = 0;
        struct prefix_rd *prd = NULL;
        mpls_label_t label = MPLS_INVALID_LABEL;
@@ -721,6 +722,7 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
        bpacket_attr_vec_arr_reset(&vecarr);
 
        addpath_encode = bgp_addpath_encode_tx(peer, afi, safi);
+       addpath_overhead = addpath_encode ? BGP_ADDPATH_ID_LEN : 0;
 
        adv = BGP_ADV_FIFO_HEAD(&subgrp->sync->update);
        while (adv) {
@@ -732,8 +734,8 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
 
                space_remaining = STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s))
                                  - BGP_MAX_PACKET_SIZE_OVERFLOW;
-               space_needed = BGP_NLRI_LENGTH + bgp_packet_mpattr_prefix_size(
-                                                        afi, safi, &rn->p);
+               space_needed = BGP_NLRI_LENGTH + addpath_overhead +
+                              bgp_packet_mpattr_prefix_size(afi, safi, &rn->p);
 
                /* When remaining space can't include NLRI and it's length.  */
                if (space_remaining < space_needed)
@@ -777,9 +779,9 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
                        space_remaining =
                                STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s))
                                - BGP_MAX_PACKET_SIZE_OVERFLOW;
-                       space_needed =
-                               BGP_NLRI_LENGTH + bgp_packet_mpattr_prefix_size(
-                                                         afi, safi, &rn->p);
+                       space_needed = BGP_NLRI_LENGTH + addpath_overhead +
+                               bgp_packet_mpattr_prefix_size(afi, safi,
+                                                             &rn->p);
 
                        /* If the attributes alone do not leave any room for
                         * NLRI then
@@ -936,6 +938,7 @@ struct bpacket *subgroup_withdraw_packet(struct update_subgroup *subgrp)
        int space_needed = 0;
        int num_pfx = 0;
        int addpath_encode = 0;
+       int addpath_overhead = 0;
        u_int32_t addpath_tx_id = 0;
        struct prefix_rd *prd = NULL;
 
@@ -952,6 +955,7 @@ struct bpacket *subgroup_withdraw_packet(struct update_subgroup *subgrp)
        s = subgrp->work;
        stream_reset(s);
        addpath_encode = bgp_addpath_encode_tx(peer, afi, safi);
+       addpath_overhead = addpath_encode ? BGP_ADDPATH_ID_LEN : 0;
 
        while ((adv = BGP_ADV_FIFO_HEAD(&subgrp->sync->withdraw)) != NULL) {
                assert(adv->rn);
@@ -962,7 +966,7 @@ struct bpacket *subgroup_withdraw_packet(struct update_subgroup *subgrp)
                space_remaining =
                        STREAM_REMAIN(s) - BGP_MAX_PACKET_SIZE_OVERFLOW;
                space_needed =
-                       BGP_NLRI_LENGTH + BGP_TOTAL_ATTR_LEN
+                       BGP_NLRI_LENGTH + addpath_overhead + BGP_TOTAL_ATTR_LEN
                        + bgp_packet_mpattr_prefix_size(afi, safi, &rn->p);
 
                if (space_remaining < space_needed)