bird/nest/rt-attr.c
Ondrej Zajicek (work) a1f5e514ef Implement onlink flag for nexthops
Add proper support for per-nexthop onlink flag in routes to handle next
hop addresses that are not covered by interface IP ranges. Supported by
kernel and static protocols.

Thanks to Vincent Bernat for the idea.
2017-07-04 23:36:21 +02:00

1323 lines
29 KiB
C

/*
* BIRD -- Route Attribute Cache
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Route attribute cache
*
* Each route entry carries a set of route attributes. Several of them
* vary from route to route, but most attributes are usually common
* for a large number of routes. To conserve memory, we've decided to
* store only the varying ones directly in the &rte and hold the rest
* in a special structure called &rta which is shared among all the
* &rte's with these attributes.
*
* Each &rta contains all the static attributes of the route (i.e.,
* those which are always present) as structure members and a list of
* dynamic attributes represented by a linked list of &ea_list
* structures, each of them consisting of an array of &eattr's containing
* the individual attributes. An attribute can be specified more than once
* in the &ea_list chain and in such case the first occurrence overrides
* the others. This semantics is used especially when someone (for example
* a filter) wishes to alter values of several dynamic attributes, but
* it wants to preserve the original attribute lists maintained by
* another module.
*
* Each &eattr contains an attribute identifier (split to protocol ID and
* per-protocol attribute ID), protocol dependent flags, a type code (consisting
* of several bit fields describing attribute characteristics) and either an
* embedded 32-bit value or a pointer to a &adata structure holding attribute
* contents.
*
* There exist two variants of &rta's -- cached and un-cached ones. Un-cached
* &rta's can have arbitrarily complex structure of &ea_list's and they
* can be modified by any module in the route processing chain. Cached
* &rta's have their attribute lists normalized (that means at most one
* &ea_list is present and its values are sorted in order to speed up
* searching), they are stored in a hash table to make fast lookup possible
* and they are provided with a use count to allow sharing.
*
* Routing tables always contain only cached &rta's.
*/
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "nest/cli.h"
#include "nest/attrs.h"
#include "lib/alloca.h"
#include "lib/hash.h"
#include "lib/idm.h"
#include "lib/resource.h"
#include "lib/string.h"
#include <stddef.h>
const char * rta_dest_names[RTD_MAX] = {
[RTD_NONE] = "",
[RTD_UNICAST] = "unicast",
[RTD_BLACKHOLE] = "blackhole",
[RTD_UNREACHABLE] = "unreachable",
[RTD_PROHIBIT] = "prohibited",
};
pool *rta_pool;
static slab *rta_slab_[4];
static slab *nexthop_slab_[4];
static slab *rte_src_slab;
static struct idm src_ids;
#define SRC_ID_INIT_SIZE 4
/* rte source hash */
#define RSH_KEY(n) n->proto, n->private_id
#define RSH_NEXT(n) n->next
#define RSH_EQ(p1,n1,p2,n2) p1 == p2 && n1 == n2
#define RSH_FN(p,n) p->hash_key ^ u32_hash(n)
#define RSH_REHASH rte_src_rehash
#define RSH_PARAMS /2, *2, 1, 1, 8, 20
#define RSH_INIT_ORDER 6
static HASH(struct rte_src) src_hash;
struct protocol *attr_class_to_protocol[EAP_MAX];
static void
rte_src_init(void)
{
rte_src_slab = sl_new(rta_pool, sizeof(struct rte_src));
idm_init(&src_ids, rta_pool, SRC_ID_INIT_SIZE);
HASH_INIT(src_hash, rta_pool, RSH_INIT_ORDER);
}
HASH_DEFINE_REHASH_FN(RSH, struct rte_src)
struct rte_src *
rt_find_source(struct proto *p, u32 id)
{
return HASH_FIND(src_hash, RSH, p, id);
}
struct rte_src *
rt_get_source(struct proto *p, u32 id)
{
struct rte_src *src = rt_find_source(p, id);
if (src)
return src;
src = sl_alloc(rte_src_slab);
src->proto = p;
src->private_id = id;
src->global_id = idm_alloc(&src_ids);
src->uc = 0;
HASH_INSERT2(src_hash, RSH, rta_pool, src);
return src;
}
void
rt_prune_sources(void)
{
HASH_WALK_FILTER(src_hash, next, src, sp)
{
if (src->uc == 0)
{
HASH_DO_REMOVE(src_hash, RSH, sp);
idm_free(&src_ids, src->global_id);
sl_free(rte_src_slab, src);
}
}
HASH_WALK_FILTER_END;
HASH_MAY_RESIZE_DOWN(src_hash, RSH, rta_pool);
}
/*
* Multipath Next Hop
*/
static inline u32
nexthop_hash(struct nexthop *x)
{
u32 h = 0;
for (; x; x = x->next)
{
h ^= ipa_hash(x->gw) ^ (h << 5) ^ (h >> 9);
for (int i = 0; i < x->labels; i++)
h ^= x->label[i] ^ (h << 6) ^ (h >> 7);
}
return h;
}
int
nexthop__same(struct nexthop *x, struct nexthop *y)
{
for (; x && y; x = x->next, y = y->next)
{
if (!ipa_equal(x->gw, y->gw) || (x->iface != y->iface) ||
(x->flags != y->flags) || (x->weight != y->weight) ||
(x->labels != y->labels))
return 0;
for (int i = 0; i < x->labels; i++)
if (x->label[i] != y->label[i])
return 0;
}
return x == y;
}
static int
nexthop_compare_node(struct nexthop *x, struct nexthop *y)
{
int r;
if (!x)
return 1;
if (!y)
return -1;
/* Should we also compare flags ? */
r = ((int) y->weight) - ((int) x->weight);
if (r)
return r;
r = ipa_compare(x->gw, y->gw);
if (r)
return r;
r = ((int) y->labels) - ((int) x->labels);
if (r)
return r;
for (int i = 0; i < y->labels; i++)
{
r = ((int) y->label[i]) - ((int) x->label[i]);
if (r)
return r;
}
return ((int) x->iface->index) - ((int) y->iface->index);
}
static inline struct nexthop *
nexthop_copy_node(const struct nexthop *src, linpool *lp)
{
struct nexthop *n = lp_alloc(lp, nexthop_size(src));
memcpy(n, src, nexthop_size(src));
n->next = NULL;
return n;
}
/**
* nexthop_merge - merge nexthop lists
* @x: list 1
* @y: list 2
* @rx: reusability of list @x
* @ry: reusability of list @y
* @max: max number of nexthops
* @lp: linpool for allocating nexthops
*
* The nexthop_merge() function takes two nexthop lists @x and @y and merges them,
* eliminating possible duplicates. The input lists must be sorted and the
* result is sorted too. The number of nexthops in result is limited by @max.
* New nodes are allocated from linpool @lp.
*
* The arguments @rx and @ry specify whether corresponding input lists may be
* consumed by the function (i.e. their nodes reused in the resulting list), in
* that case the caller should not access these lists after that. To eliminate
* issues with deallocation of these lists, the caller should use some form of
* bulk deallocation (e.g. stack or linpool) to free these nodes when the
* resulting list is no longer needed. When reusability is not set, the
* corresponding lists are not modified nor linked from the resulting list.
*/
struct nexthop *
nexthop_merge(struct nexthop *x, struct nexthop *y, int rx, int ry, int max, linpool *lp)
{
struct nexthop *root = NULL;
struct nexthop **n = &root;
while ((x || y) && max--)
{
int cmp = nexthop_compare_node(x, y);
if (cmp < 0)
{
*n = rx ? x : nexthop_copy_node(x, lp);
x = x->next;
}
else if (cmp > 0)
{
*n = ry ? y : nexthop_copy_node(y, lp);
y = y->next;
}
else
{
*n = rx ? x : (ry ? y : nexthop_copy_node(x, lp));
x = x->next;
y = y->next;
}
n = &((*n)->next);
}
*n = NULL;
return root;
}
void
nexthop_insert(struct nexthop **n, struct nexthop *x)
{
for (; *n; n = &((*n)->next))
{
int cmp = nexthop_compare_node(*n, x);
if (cmp < 0)
continue;
else if (cmp > 0)
break;
else
return;
}
x->next = *n;
*n = x;
}
int
nexthop_is_sorted(struct nexthop *x)
{
for (; x && x->next; x = x->next)
if (nexthop_compare_node(x, x->next) >= 0)
return 0;
return 1;
}
static inline slab *
nexthop_slab(struct nexthop *nh)
{
return nexthop_slab_[MIN(nh->labels, 3)];
}
static struct nexthop *
nexthop_copy(struct nexthop *o)
{
struct nexthop *first = NULL;
struct nexthop **last = &first;
for (; o; o = o->next)
{
struct nexthop *n = sl_alloc(nexthop_slab(o));
n->gw = o->gw;
n->iface = o->iface;
n->next = NULL;
n->weight = o->weight;
n->labels = o->labels;
for (int i=0; i<o->labels; i++)
n->label[i] = o->label[i];
*last = n;
last = &(n->next);
}
return first;
}
static void
nexthop_free(struct nexthop *o)
{
struct nexthop *n;
while (o)
{
n = o->next;
sl_free(nexthop_slab(o), o);
o = n;
}
}
/*
* Extended Attributes
*/
static inline eattr *
ea__find(ea_list *e, unsigned id)
{
eattr *a;
int l, r, m;
while (e)
{
if (e->flags & EALF_BISECT)
{
l = 0;
r = e->count - 1;
while (l <= r)
{
m = (l+r) / 2;
a = &e->attrs[m];
if (a->id == id)
return a;
else if (a->id < id)
l = m+1;
else
r = m-1;
}
}
else
for(m=0; m<e->count; m++)
if (e->attrs[m].id == id)
return &e->attrs[m];
e = e->next;
}
return NULL;
}
/**
* ea_find - find an extended attribute
* @e: attribute list to search in
* @id: attribute ID to search for
*
* Given an extended attribute list, ea_find() searches for a first
* occurrence of an attribute with specified ID, returning either a pointer
* to its &eattr structure or %NULL if no such attribute exists.
*/
eattr *
ea_find(ea_list *e, unsigned id)
{
eattr *a = ea__find(e, id & EA_CODE_MASK);
if (a && (a->type & EAF_TYPE_MASK) == EAF_TYPE_UNDEF &&
!(id & EA_ALLOW_UNDEF))
return NULL;
return a;
}
/**
* ea_walk - walk through extended attributes
* @s: walk state structure
* @id: start of attribute ID interval
* @max: length of attribute ID interval
*
* Given an extended attribute list, ea_walk() walks through the list looking
* for first occurrences of attributes with ID in specified interval from @id to
* (@id + @max - 1), returning pointers to found &eattr structures, storing its
* walk state in @s for subsequent calls.
*
* The function ea_walk() is supposed to be called in a loop, with initially
* zeroed walk state structure @s with filled the initial extended attribute
* list, returning one found attribute in each call or %NULL when no other
* attribute exists. The extended attribute list or the arguments should not be
* modified between calls. The maximum value of @max is 128.
*/
eattr *
ea_walk(struct ea_walk_state *s, uint id, uint max)
{
ea_list *e = s->eattrs;
eattr *a = s->ea;
eattr *a_max;
max = id + max;
if (a)
goto step;
for (; e; e = e->next)
{
if (e->flags & EALF_BISECT)
{
int l, r, m;
l = 0;
r = e->count - 1;
while (l < r)
{
m = (l+r) / 2;
if (e->attrs[m].id < id)
l = m + 1;
else
r = m;
}
a = e->attrs + l;
}
else
a = e->attrs;
step:
a_max = e->attrs + e->count;
for (; a < a_max; a++)
if ((a->id >= id) && (a->id < max))
{
int n = a->id - id;
if (BIT32_TEST(s->visited, n))
continue;
BIT32_SET(s->visited, n);
if ((a->type & EAF_TYPE_MASK) == EAF_TYPE_UNDEF)
continue;
s->eattrs = e;
s->ea = a;
return a;
}
else if (e->flags & EALF_BISECT)
break;
}
return NULL;
}
/**
* ea_get_int - fetch an integer attribute
* @e: attribute list
* @id: attribute ID
* @def: default value
*
* This function is a shortcut for retrieving a value of an integer attribute
* by calling ea_find() to find the attribute, extracting its value or returning
* a provided default if no such attribute is present.
*/
int
ea_get_int(ea_list *e, unsigned id, int def)
{
eattr *a = ea_find(e, id);
if (!a)
return def;
return a->u.data;
}
static inline void
ea_do_sort(ea_list *e)
{
unsigned n = e->count;
eattr *a = e->attrs;
eattr *b = alloca(n * sizeof(eattr));
unsigned s, ss;
/* We need to use a stable sorting algorithm, hence mergesort */
do
{
s = ss = 0;
while (s < n)
{
eattr *p, *q, *lo, *hi;
p = b;
ss = s;
*p++ = a[s++];
while (s < n && p[-1].id <= a[s].id)
*p++ = a[s++];
if (s < n)
{
q = p;
*p++ = a[s++];
while (s < n && p[-1].id <= a[s].id)
*p++ = a[s++];
lo = b;
hi = q;
s = ss;
while (lo < q && hi < p)
if (lo->id <= hi->id)
a[s++] = *lo++;
else
a[s++] = *hi++;
while (lo < q)
a[s++] = *lo++;
while (hi < p)
a[s++] = *hi++;
}
}
}
while (ss);
}
static inline void
ea_do_prune(ea_list *e)
{
eattr *s, *d, *l, *s0;
int i = 0;
/* Discard duplicates and undefs. Do you remember sorting was stable? */
s = d = e->attrs;
l = e->attrs + e->count;
while (s < l)
{
s0 = s++;
while (s < l && s->id == s[-1].id)
s++;
/* s0 is the most recent version, s[-1] the oldest one */
if ((s0->type & EAF_TYPE_MASK) != EAF_TYPE_UNDEF)
{
*d = *s0;
d->type = (d->type & ~(EAF_ORIGINATED|EAF_FRESH)) | (s[-1].type & EAF_ORIGINATED);
d++;
i++;
}
}
e->count = i;
}
/**
* ea_sort - sort an attribute list
* @e: list to be sorted
*
* This function takes a &ea_list chain and sorts the attributes
* within each of its entries.
*
* If an attribute occurs multiple times in a single &ea_list,
* ea_sort() leaves only the first (the only significant) occurrence.
*/
void
ea_sort(ea_list *e)
{
while (e)
{
if (!(e->flags & EALF_SORTED))
{
ea_do_sort(e);
ea_do_prune(e);
e->flags |= EALF_SORTED;
}
if (e->count > 5)
e->flags |= EALF_BISECT;
e = e->next;
}
}
/**
* ea_scan - estimate attribute list size
* @e: attribute list
*
* This function calculates an upper bound of the size of
* a given &ea_list after merging with ea_merge().
*/
unsigned
ea_scan(ea_list *e)
{
unsigned cnt = 0;
while (e)
{
cnt += e->count;
e = e->next;
}
return sizeof(ea_list) + sizeof(eattr)*cnt;
}
/**
* ea_merge - merge segments of an attribute list
* @e: attribute list
* @t: buffer to store the result to
*
* This function takes a possibly multi-segment attribute list
* and merges all of its segments to one.
*
* The primary use of this function is for &ea_list normalization:
* first call ea_scan() to determine how much memory will the result
* take, then allocate a buffer (usually using alloca()), merge the
* segments with ea_merge() and finally sort and prune the result
* by calling ea_sort().
*/
void
ea_merge(ea_list *e, ea_list *t)
{
eattr *d = t->attrs;
t->flags = 0;
t->count = 0;
t->next = NULL;
while (e)
{
memcpy(d, e->attrs, sizeof(eattr)*e->count);
t->count += e->count;
d += e->count;
e = e->next;
}
}
/**
* ea_same - compare two &ea_list's
* @x: attribute list
* @y: attribute list
*
* ea_same() compares two normalized attribute lists @x and @y and returns
* 1 if they contain the same attributes, 0 otherwise.
*/
int
ea_same(ea_list *x, ea_list *y)
{
int c;
if (!x || !y)
return x == y;
ASSERT(!x->next && !y->next);
if (x->count != y->count)
return 0;
for(c=0; c<x->count; c++)
{
eattr *a = &x->attrs[c];
eattr *b = &y->attrs[c];
if (a->id != b->id ||
a->flags != b->flags ||
a->type != b->type ||
((a->type & EAF_EMBEDDED) ? a->u.data != b->u.data : !adata_same(a->u.ptr, b->u.ptr)))
return 0;
}
return 1;
}
static inline ea_list *
ea_list_copy(ea_list *o)
{
ea_list *n;
unsigned i, len;
if (!o)
return NULL;
ASSERT(!o->next);
len = sizeof(ea_list) + sizeof(eattr) * o->count;
n = mb_alloc(rta_pool, len);
memcpy(n, o, len);
n->flags |= EALF_CACHED;
for(i=0; i<o->count; i++)
{
eattr *a = &n->attrs[i];
if (!(a->type & EAF_EMBEDDED))
{
unsigned size = sizeof(struct adata) + a->u.ptr->length;
struct adata *d = mb_alloc(rta_pool, size);
memcpy(d, a->u.ptr, size);
a->u.ptr = d;
}
}
return n;
}
static inline void
ea_free(ea_list *o)
{
int i;
if (o)
{
ASSERT(!o->next);
for(i=0; i<o->count; i++)
{
eattr *a = &o->attrs[i];
if (!(a->type & EAF_EMBEDDED))
mb_free(a->u.ptr);
}
mb_free(o);
}
}
static int
get_generic_attr(eattr *a, byte **buf, int buflen UNUSED)
{
if (a->id == EA_GEN_IGP_METRIC)
{
*buf += bsprintf(*buf, "igp_metric");
return GA_NAME;
}
return GA_UNKNOWN;
}
void
ea_format_bitfield(struct eattr *a, byte *buf, int bufsize, const char **names, int min, int max)
{
byte *bound = buf + bufsize - 32;
u32 data = a->u.data;
int i;
for (i = min; i < max; i++)
if ((data & (1u << i)) && names[i])
{
if (buf > bound)
{
strcpy(buf, " ...");
return;
}
buf += bsprintf(buf, " %s", names[i]);
data &= ~(1u << i);
}
if (data)
bsprintf(buf, " %08x", data);
return;
}
static inline void
opaque_format(struct adata *ad, byte *buf, uint size)
{
byte *bound = buf + size - 10;
uint i;
for(i = 0; i < ad->length; i++)
{
if (buf > bound)
{
strcpy(buf, " ...");
return;
}
if (i)
*buf++ = ' ';
buf += bsprintf(buf, "%02x", ad->data[i]);
}
*buf = 0;
return;
}
static inline void
ea_show_int_set(struct cli *c, struct adata *ad, int way, byte *pos, byte *buf, byte *end)
{
int i = int_set_format(ad, way, 0, pos, end - pos);
cli_printf(c, -1012, "\t%s", buf);
while (i)
{
i = int_set_format(ad, way, i, buf, end - buf - 1);
cli_printf(c, -1012, "\t\t%s", buf);
}
}
static inline void
ea_show_ec_set(struct cli *c, struct adata *ad, byte *pos, byte *buf, byte *end)
{
int i = ec_set_format(ad, 0, pos, end - pos);
cli_printf(c, -1012, "\t%s", buf);
while (i)
{
i = ec_set_format(ad, i, buf, end - buf - 1);
cli_printf(c, -1012, "\t\t%s", buf);
}
}
static inline void
ea_show_lc_set(struct cli *c, struct adata *ad, byte *pos, byte *buf, byte *end)
{
int i = lc_set_format(ad, 0, pos, end - pos);
cli_printf(c, -1012, "\t%s", buf);
while (i)
{
i = lc_set_format(ad, i, buf, end - buf - 1);
cli_printf(c, -1012, "\t\t%s", buf);
}
}
/**
* ea_show - print an &eattr to CLI
* @c: destination CLI
* @e: attribute to be printed
*
* This function takes an extended attribute represented by its &eattr
* structure and prints it to the CLI according to the type information.
*
* If the protocol defining the attribute provides its own
* get_attr() hook, it's consulted first.
*/
void
ea_show(struct cli *c, eattr *e)
{
struct protocol *p;
int status = GA_UNKNOWN;
struct adata *ad = (e->type & EAF_EMBEDDED) ? NULL : e->u.ptr;
byte buf[CLI_MSG_SIZE];
byte *pos = buf, *end = buf + sizeof(buf);
if (p = attr_class_to_protocol[EA_PROTO(e->id)])
{
pos += bsprintf(pos, "%s.", p->name);
if (p->get_attr)
status = p->get_attr(e, pos, end - pos);
pos += strlen(pos);
}
else if (EA_PROTO(e->id))
pos += bsprintf(pos, "%02x.", EA_PROTO(e->id));
else
status = get_generic_attr(e, &pos, end - pos);
if (status < GA_NAME)
pos += bsprintf(pos, "%02x", EA_ID(e->id));
if (status < GA_FULL)
{
*pos++ = ':';
*pos++ = ' ';
switch (e->type & EAF_TYPE_MASK)
{
case EAF_TYPE_INT:
bsprintf(pos, "%u", e->u.data);
break;
case EAF_TYPE_OPAQUE:
opaque_format(ad, pos, end - pos);
break;
case EAF_TYPE_IP_ADDRESS:
bsprintf(pos, "%I", *(ip_addr *) ad->data);
break;
case EAF_TYPE_ROUTER_ID:
bsprintf(pos, "%R", e->u.data);
break;
case EAF_TYPE_AS_PATH:
as_path_format(ad, pos, end - pos);
break;
case EAF_TYPE_BITFIELD:
bsprintf(pos, "%08x", e->u.data);
break;
case EAF_TYPE_INT_SET:
ea_show_int_set(c, ad, 1, pos, buf, end);
return;
case EAF_TYPE_EC_SET:
ea_show_ec_set(c, ad, pos, buf, end);
return;
case EAF_TYPE_LC_SET:
ea_show_lc_set(c, ad, pos, buf, end);
return;
case EAF_TYPE_UNDEF:
default:
bsprintf(pos, "<type %02x>", e->type);
}
}
cli_printf(c, -1012, "\t%s", buf);
}
/**
* ea_dump - dump an extended attribute
* @e: attribute to be dumped
*
* ea_dump() dumps contents of the extended attribute given to
* the debug output.
*/
void
ea_dump(ea_list *e)
{
int i;
if (!e)
{
debug("NONE");
return;
}
while (e)
{
debug("[%c%c%c]",
(e->flags & EALF_SORTED) ? 'S' : 's',
(e->flags & EALF_BISECT) ? 'B' : 'b',
(e->flags & EALF_CACHED) ? 'C' : 'c');
for(i=0; i<e->count; i++)
{
eattr *a = &e->attrs[i];
debug(" %02x:%02x.%02x", EA_PROTO(a->id), EA_ID(a->id), a->flags);
if (a->type & EAF_TEMP)
debug("T");
debug("=%c", "?iO?I?P???S?????" [a->type & EAF_TYPE_MASK]);
if (a->type & EAF_ORIGINATED)
debug("o");
if (a->type & EAF_EMBEDDED)
debug(":%08x", a->u.data);
else
{
int j, len = a->u.ptr->length;
debug("[%d]:", len);
for(j=0; j<len; j++)
debug("%02x", a->u.ptr->data[j]);
}
}
if (e = e->next)
debug(" | ");
}
}
/**
* ea_hash - calculate an &ea_list hash key
* @e: attribute list
*
* ea_hash() takes an extended attribute list and calculated a hopefully
* uniformly distributed hash value from its contents.
*/
inline uint
ea_hash(ea_list *e)
{
const u64 mul = 0x68576150f3d6847;
u64 h = 0xafcef24eda8b29;
int i;
if (e) /* Assuming chain of length 1 */
{
for(i=0; i<e->count; i++)
{
struct eattr *a = &e->attrs[i];
h ^= a->id; h *= mul;
if (a->type & EAF_EMBEDDED)
h ^= a->u.data;
else
{
struct adata *d = a->u.ptr;
h ^= mem_hash(d->data, d->length);
}
h *= mul;
}
}
return (h >> 32) ^ (h & 0xffffffff);
}
/**
* ea_append - concatenate &ea_list's
* @to: destination list (can be %NULL)
* @what: list to be appended (can be %NULL)
*
* This function appends the &ea_list @what at the end of
* &ea_list @to and returns a pointer to the resulting list.
*/
ea_list *
ea_append(ea_list *to, ea_list *what)
{
ea_list *res;
if (!to)
return what;
res = to;
while (to->next)
to = to->next;
to->next = what;
return res;
}
/*
* rta's
*/
static uint rta_cache_count;
static uint rta_cache_size = 32;
static uint rta_cache_limit;
static uint rta_cache_mask;
static rta **rta_hash_table;
static void
rta_alloc_hash(void)
{
rta_hash_table = mb_allocz(rta_pool, sizeof(rta *) * rta_cache_size);
if (rta_cache_size < 32768)
rta_cache_limit = rta_cache_size * 2;
else
rta_cache_limit = ~0;
rta_cache_mask = rta_cache_size - 1;
}
static inline uint
rta_hash(rta *a)
{
u64 h;
mem_hash_init(&h);
#define MIX(f) mem_hash_mix(&h, &(a->f), sizeof(a->f));
MIX(src);
MIX(hostentry);
MIX(from);
MIX(igp_metric);
MIX(source);
MIX(scope);
MIX(dest);
#undef MIX
return mem_hash_value(&h) ^ nexthop_hash(&(a->nh)) ^ ea_hash(a->eattrs);
}
static inline int
rta_same(rta *x, rta *y)
{
return (x->src == y->src &&
x->source == y->source &&
x->scope == y->scope &&
x->dest == y->dest &&
x->igp_metric == y->igp_metric &&
ipa_equal(x->from, y->from) &&
x->hostentry == y->hostentry &&
nexthop_same(&(x->nh), &(y->nh)) &&
ea_same(x->eattrs, y->eattrs));
}
static inline slab *
rta_slab(rta *a)
{
return rta_slab_[a->nh.labels > 2 ? 3 : a->nh.labels];
}
static rta *
rta_copy(rta *o)
{
rta *r = sl_alloc(rta_slab(o));
memcpy(r, o, rta_size(o));
r->uc = 1;
r->nh.next = nexthop_copy(o->nh.next);
r->eattrs = ea_list_copy(o->eattrs);
return r;
}
static inline void
rta_insert(rta *r)
{
uint h = r->hash_key & rta_cache_mask;
r->next = rta_hash_table[h];
if (r->next)
r->next->pprev = &r->next;
r->pprev = &rta_hash_table[h];
rta_hash_table[h] = r;
}
static void
rta_rehash(void)
{
uint ohs = rta_cache_size;
uint h;
rta *r, *n;
rta **oht = rta_hash_table;
rta_cache_size = 2*rta_cache_size;
DBG("Rehashing rta cache from %d to %d entries.\n", ohs, rta_cache_size);
rta_alloc_hash();
for(h=0; h<ohs; h++)
for(r=oht[h]; r; r=n)
{
n = r->next;
rta_insert(r);
}
mb_free(oht);
}
/**
* rta_lookup - look up a &rta in attribute cache
* @o: a un-cached &rta
*
* rta_lookup() gets an un-cached &rta structure and returns its cached
* counterpart. It starts with examining the attribute cache to see whether
* there exists a matching entry. If such an entry exists, it's returned and
* its use count is incremented, else a new entry is created with use count
* set to 1.
*
* The extended attribute lists attached to the &rta are automatically
* converted to the normalized form.
*/
rta *
rta_lookup(rta *o)
{
rta *r;
uint h;
ASSERT(!(o->aflags & RTAF_CACHED));
if (o->eattrs)
{
if (o->eattrs->next) /* Multiple ea_list's, need to merge them */
{
ea_list *ml = alloca(ea_scan(o->eattrs));
ea_merge(o->eattrs, ml);
o->eattrs = ml;
}
ea_sort(o->eattrs);
}
h = rta_hash(o);
for(r=rta_hash_table[h & rta_cache_mask]; r; r=r->next)
if (r->hash_key == h && rta_same(r, o))
return rta_clone(r);
r = rta_copy(o);
r->hash_key = h;
r->aflags = RTAF_CACHED;
rt_lock_source(r->src);
rt_lock_hostentry(r->hostentry);
rta_insert(r);
if (++rta_cache_count > rta_cache_limit)
rta_rehash();
return r;
}
void
rta__free(rta *a)
{
ASSERT(rta_cache_count && (a->aflags & RTAF_CACHED));
rta_cache_count--;
*a->pprev = a->next;
if (a->next)
a->next->pprev = a->pprev;
rt_unlock_hostentry(a->hostentry);
rt_unlock_source(a->src);
if (a->nh.next)
nexthop_free(a->nh.next);
ea_free(a->eattrs);
a->aflags = 0; /* Poison the entry */
sl_free(rta_slab(a), a);
}
rta *
rta_do_cow(rta *o, linpool *lp)
{
rta *r = lp_alloc(lp, rta_size(o));
memcpy(r, o, rta_size(o));
for (struct nexthop **nhn = &(r->nh.next), *nho = o->nh.next; nho; nho = nho->next)
{
*nhn = lp_alloc(lp, nexthop_size(nho));
memcpy(*nhn, nho, nexthop_size(nho));
nhn = &((*nhn)->next);
}
r->aflags = 0;
r->uc = 0;
return r;
}
/**
* rta_dump - dump route attributes
* @a: attribute structure to dump
*
* This function takes a &rta and dumps its contents to the debug output.
*/
void
rta_dump(rta *a)
{
static char *rts[] = { "RTS_DUMMY", "RTS_STATIC", "RTS_INHERIT", "RTS_DEVICE",
"RTS_STAT_DEV", "RTS_REDIR", "RTS_RIP",
"RTS_OSPF", "RTS_OSPF_IA", "RTS_OSPF_EXT1",
"RTS_OSPF_EXT2", "RTS_BGP", "RTS_PIPE", "RTS_BABEL" };
static char *rtd[] = { "", " DEV", " HOLE", " UNREACH", " PROHIBIT" };
debug("p=%s uc=%d %s %s%s h=%04x",
a->src->proto->name, a->uc, rts[a->source], ip_scope_text(a->scope),
rtd[a->dest], a->hash_key);
if (!(a->aflags & RTAF_CACHED))
debug(" !CACHED");
debug(" <-%I", a->from);
if (a->dest == RTD_UNICAST)
for (struct nexthop *nh = &(a->nh); nh; nh = nh->next)
{
if (ipa_nonzero(nh->gw)) debug(" ->%I", nh->gw);
if (nh->labels) debug(" L %d", nh->label[0]);
for (int i=1; i<nh->labels; i++)
debug("/%d", nh->label[i]);
debug(" [%s]", nh->iface ? nh->iface->name : "???");
}
if (a->eattrs)
{
debug(" EA: ");
ea_dump(a->eattrs);
}
}
/**
* rta_dump_all - dump attribute cache
*
* This function dumps the whole contents of route attribute cache
* to the debug output.
*/
void
rta_dump_all(void)
{
rta *a;
uint h;
debug("Route attribute cache (%d entries, rehash at %d):\n", rta_cache_count, rta_cache_limit);
for(h=0; h<rta_cache_size; h++)
for(a=rta_hash_table[h]; a; a=a->next)
{
debug("%p ", a);
rta_dump(a);
debug("\n");
}
debug("\n");
}
void
rta_show(struct cli *c, rta *a, ea_list *eal)
{
static char *src_names[] = { "dummy", "static", "inherit", "device", "static-device", "redirect",
"RIP", "OSPF", "OSPF-IA", "OSPF-E1", "OSPF-E2", "BGP", "pipe" };
int i;
cli_printf(c, -1008, "\tType: %s %s", src_names[a->source], ip_scope_text(a->scope));
if (!eal)
eal = a->eattrs;
for(; eal; eal=eal->next)
for(i=0; i<eal->count; i++)
ea_show(c, &eal->attrs[i]);
}
/**
* rta_init - initialize route attribute cache
*
* This function is called during initialization of the routing
* table module to set up the internals of the attribute cache.
*/
void
rta_init(void)
{
rta_pool = rp_new(&root_pool, "Attributes");
rta_slab_[0] = sl_new(rta_pool, sizeof(rta));
rta_slab_[1] = sl_new(rta_pool, sizeof(rta) + sizeof(u32));
rta_slab_[2] = sl_new(rta_pool, sizeof(rta) + sizeof(u32)*2);
rta_slab_[3] = sl_new(rta_pool, sizeof(rta) + sizeof(u32)*MPLS_MAX_LABEL_STACK);
nexthop_slab_[0] = sl_new(rta_pool, sizeof(struct nexthop));
nexthop_slab_[1] = sl_new(rta_pool, sizeof(struct nexthop) + sizeof(u32));
nexthop_slab_[2] = sl_new(rta_pool, sizeof(struct nexthop) + sizeof(u32)*2);
nexthop_slab_[3] = sl_new(rta_pool, sizeof(struct nexthop) + sizeof(u32)*MPLS_MAX_LABEL_STACK);
rta_alloc_hash();
rte_src_init();
}
/*
* Documentation for functions declared inline in route.h
*/
#if 0
/**
* rta_clone - clone route attributes
* @r: a &rta to be cloned
*
* rta_clone() takes a cached &rta and returns its identical cached
* copy. Currently it works by just returning the original &rta with
* its use count incremented.
*/
static inline rta *rta_clone(rta *r)
{ DUMMY; }
/**
* rta_free - free route attributes
* @r: a &rta to be freed
*
* If you stop using a &rta (for example when deleting a route which uses
* it), you need to call rta_free() to notify the attribute cache the
* attribute is no longer in use and can be freed if you were the last
* user (which rta_free() tests by inspecting the use count).
*/
static inline void rta_free(rta *r)
{ DUMMY; }
#endif