diff options
Diffstat (limited to 'bgpd/bgp_attr.c')
| -rw-r--r-- | bgpd/bgp_attr.c | 123 |
1 files changed, 101 insertions, 22 deletions
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 7fc9749e..e3ef01d7 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -493,7 +493,38 @@ bgp_attr_hash_alloc (void *p) return attr; } -/* Internet argument attribute. */ +/*------------------------------------------------------------------------------ + * Internet argument attribute. + * + * 1. "internalise" and increase reference count for each of: + * + * attr->aspath + * attr->community + * attr->extra->ecommunity + * attr->extra->cluster + * attr->extra->transit + * + * Noting that the reference count for each of these is zero if they have not + * yet been internalised. + * + * Each of these pointers is updated to point at either a new entry in the + * relevant attribute store, or at the existing entry. + * + * 2. "internalise" the complete attribute object and increase its reference + * count. + * + * If the attribute collection is new, then this function returns a pointer + * to a brand new attribute object, complete with a copy of the attr->extra. + * + * If the attribute collection is not new, then this function returns a + * pointer to the stored attribute object. + * + * In any event, the pointer returned != pointer passed in. + * + * NB: the incoming attr reference count is ignored. + * + * Note that the original attr object remains with its own attr->extra object. + */ struct attr * bgp_attr_intern (struct attr *attr) { @@ -547,8 +578,10 @@ bgp_attr_intern (struct attr *attr) return find; } - -/* Make network statement's attribute. */ +/* Make network statement's attribute. + * + * All elements are interned, but not the attribute set itself. + */ struct attr * bgp_attr_default_set (struct attr *attr, u_char origin) { @@ -641,7 +674,27 @@ bgp_attr_aggregate_intern (struct bgp *bgp, u_char origin, return new; } -/* Free bgp attribute and aspath. */ +/*------------------------------------------------------------------------------ + * Free bgp attribute and aspath. + * + * For all the elements of the given attributes: + * + * if the reference count != 0, decrement it + * if the reference count is now zero, remove from hash table and discard + * stored value. + * + * For the attribute object itself: + * + * decrement the reference count + * if the reference count is now zero, remove from hash table and discard + * stored value. + * + * So... do NOT do this to a set of attributes whose elements have not been + * interned ! + * + * Can do this to an attribute object which has not been interned, because its + * reference count SHOULD be zero. + */ void bgp_attr_unintern (struct attr *attr) { @@ -652,8 +705,7 @@ bgp_attr_unintern (struct attr *attr) struct cluster_list *cluster = NULL; struct transit *transit = NULL; - /* Decrement attribute reference. */ - attr->refcnt--; + /* Decrement attribute reference. */ aspath = attr->aspath; community = attr->community; if (attr->extra) @@ -663,16 +715,20 @@ bgp_attr_unintern (struct attr *attr) transit = attr->extra->transit; } - /* If reference becomes zero then free attribute object. */ - if (attr->refcnt == 0) + /* If reference becomes zero then free attribute object. */ + if (attr->refcnt != 0) { - ret = hash_release (attrhash, attr); - assert (ret != NULL); - bgp_attr_extra_free (attr); - XFREE (MTYPE_ATTR, attr); - } - - /* aspath refcount shoud be decrement. */ + --attr->refcnt ; + if (attr->refcnt == 0) + { + ret = hash_release (attrhash, attr); + assert (ret != NULL); + bgp_attr_extra_free (attr); + XFREE (MTYPE_ATTR, attr); + } ; + } ; + + /* aspath refcount should be decremented. */ if (aspath) aspath_unintern (aspath); if (community) @@ -685,21 +741,27 @@ bgp_attr_unintern (struct attr *attr) transit_unintern (transit); } +/*------------------------------------------------------------------------------ + * Release any element whose reference count is zero. + * + * This is used where attributes have been replaced, but not internalised, and + * which are no longer of interest -- typically where a route-map returns DENY. + */ void bgp_attr_flush (struct attr *attr) { - if (attr->aspath && ! attr->aspath->refcnt) + if (attr->aspath && (attr->aspath->refcnt == 0)) aspath_free (attr->aspath); - if (attr->community && ! attr->community->refcnt) + if (attr->community && (attr->community->refcnt == 0)) community_free (attr->community); if (attr->extra) { struct attr_extra *attre = attr->extra; - if (attre->ecommunity && ! attre->ecommunity->refcnt) + if (attre->ecommunity && (attre->ecommunity->refcnt == 0)) ecommunity_free (attre->ecommunity); - if (attre->cluster && ! attre->cluster->refcnt) + if (attre->cluster && (attre->cluster->refcnt == 0)) cluster_free (attre->cluster); - if (attre->transit && ! attre->transit->refcnt) + if (attre->transit && ! (attre->transit->refcnt == 0)) transit_free (attre->transit); } } @@ -1538,8 +1600,25 @@ bgp_attr_unknown (struct peer *peer, struct attr *attr, u_char flag, return 0; } -/* Read attribute of update packet. This function is called from - bgp_update() in bgpd.c. */ +/*------------------------------------------------------------------------------ + * Read attribute of update packet. + * + * This function is called from bgp_update() in bgpd.c. + * + * NB: expects the structures pointed to by: + * + * attr + * mp_update + * mp_withdraw + * + * to be zeroised on entry to this function. + * + * Any elements in attr or attr->extra will be internalised as they are set. + * (So their reference counts will *not* be zero.) + * + * However, the attr object itself is NOT internalised. + * (So its reference count will be zero.) + */ int bgp_attr_parse (struct peer *peer, struct attr *attr, bgp_size_t size, struct bgp_nlri *mp_update, struct bgp_nlri *mp_withdraw) |