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isisd: add support for Prefix-SID subtlv

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Extend isisd's TLV parser to support the Prefix-SID subtlv as per
draft-ietf-isis-segment-routing-extensions-19

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
This commit is contained in:
Christian Franke 2018-05-25 13:26:27 +02:00
parent d4cff91a06
commit bd507085e0
2 changed files with 201 additions and 11 deletions
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182
isisd/isis_tlvs.c
View File

@ -107,6 +107,111 @@ static const struct tlv_ops *tlv_table[ISIS_CONTEXT_MAX][ISIS_TLV_MAX];
/* Prototypes */
static void append_item(struct isis_item_list *dest, struct isis_item *item);
/* Functions for Sub-TLV 3 SR Prefix-SID */
static struct isis_item *copy_item_prefix_sid(struct isis_item *i)
{
struct isis_prefix_sid *sid = (struct isis_prefix_sid *)i;
struct isis_prefix_sid *rv = XCALLOC(MTYPE_ISIS_SUBTLV, sizeof(*rv));
rv->flags = sid->flags;
rv->algorithm = sid->algorithm;
rv->value = sid->value;
return (struct isis_item *)rv;
}
static void format_item_prefix_sid(uint16_t mtid, struct isis_item *i,
struct sbuf *buf, int indent)
{
struct isis_prefix_sid *sid = (struct isis_prefix_sid *)i;
sbuf_push(buf, indent, "SR Prefix-SID:\n");
sbuf_push(buf, indent, " Flags:%s%s%s%s%s%s\n",
sid->flags & ISIS_PREFIX_SID_READVERTISED ? " READVERTISED" : "",
sid->flags & ISIS_PREFIX_SID_NODE ? " NODE" : "",
sid->flags & ISIS_PREFIX_SID_NO_PHP ? " NO_PHP" : "",
sid->flags & ISIS_PREFIX_SID_EXPLICIT_NULL ? " EXPLICIT-NULL" : "",
sid->flags & ISIS_PREFIX_SID_VALUE ? " VALUE" : "",
sid->flags & ISIS_PREFIX_SID_LOCAL ? " LOCAL" : "");
sbuf_push(buf, indent, " Algorithm: %" PRIu8 "\n", sid->algorithm);
if (sid->flags & ISIS_PREFIX_SID_VALUE) {
sbuf_push(buf, indent, "Label: %" PRIu32 "\n", sid->value);
} else {
sbuf_push(buf, indent, "Index: %" PRIu32 "\n", sid->value);
}
}
static void free_item_prefix_sid(struct isis_item *i)
{
XFREE(MTYPE_ISIS_SUBTLV, i);
}
static int pack_item_prefix_sid(struct isis_item *i, struct stream *s)
{
struct isis_prefix_sid *sid = (struct isis_prefix_sid *)i;
uint8_t size = (sid->flags & ISIS_PREFIX_SID_VALUE) ? 5 : 6;
if (STREAM_WRITEABLE(s) < size)
return 1;
stream_putc(s, sid->flags);
stream_putc(s, sid->algorithm);
if (sid->flags & ISIS_PREFIX_SID_VALUE) {
stream_put3(s, sid->value);
} else {
stream_putl(s, sid->value);
}
return 0;
}
static int unpack_item_prefix_sid(uint16_t mtid, uint8_t len, struct stream *s,
struct sbuf *log, void *dest, int indent)
{
struct isis_subtlvs *subtlvs = dest;
struct isis_prefix_sid sid = {
};
sbuf_push(log, indent, "Unpacking SR Prefix-SID...\n");
if (len < 5) {
sbuf_push(log, indent,
"Not enough data left. (expected 5 or more bytes, got %" PRIu8 ")\n",
len);
return 1;
}
sid.flags = stream_getc(s);
if ((sid.flags & ISIS_PREFIX_SID_VALUE)
!= (sid.flags & ISIS_PREFIX_SID_LOCAL)) {
sbuf_push(log, indent, "Flags inplausible: Local Flag needs to match Value Flag\n");
return 0;
}
sid.algorithm = stream_getc(s);
uint8_t expected_size = (sid.flags & ISIS_PREFIX_SID_VALUE) ? 5 : 6;
if (len != expected_size) {
sbuf_push(log, indent,
"TLV size differs from expected size. "
"(expected %u but got %" PRIu8 ")\n",
expected_size, len);
return 1;
}
if (sid.flags & ISIS_PREFIX_SID_VALUE) {
sid.value = stream_get3(s);
} else {
sid.value = stream_getl(s);
}
format_item_prefix_sid(mtid, (struct isis_item *)&sid, log, indent + 2);
append_item(&subtlvs->prefix_sids, copy_item_prefix_sid((struct isis_item *)&sid));
return 0;
}
/* Functions for Sub-TVL ??? IPv6 Source Prefix */
static struct prefix_ipv6 *copy_subtlv_ipv6_source_prefix(struct prefix_ipv6 *p)
@ -198,14 +303,36 @@ static int unpack_subtlv_ipv6_source_prefix(enum isis_tlv_context context,
memcpy(subtlvs->source_prefix, &p, sizeof(p));
return 0;
}
static void init_item_list(struct isis_item_list *items);
static struct isis_item *copy_item(enum isis_tlv_context context,
enum isis_tlv_type type,
struct isis_item *item);
static void copy_items(enum isis_tlv_context context, enum isis_tlv_type type,
struct isis_item_list *src, struct isis_item_list *dest);
static void format_items_(uint16_t mtid, enum isis_tlv_context context,
enum isis_tlv_type type, struct isis_item_list *items,
struct sbuf *buf, int indent);
#define format_items(...) format_items_(ISIS_MT_IPV4_UNICAST, __VA_ARGS__)
static void free_items(enum isis_tlv_context context, enum isis_tlv_type type,
struct isis_item_list *items);
static int pack_items_(uint16_t mtid, enum isis_tlv_context context,
enum isis_tlv_type type, struct isis_item_list *items,
struct stream *s, struct isis_tlvs **fragment_tlvs,
struct pack_order_entry *pe,
struct isis_tlvs *(*new_fragment)(struct list *l),
struct list *new_fragment_arg);
#define pack_items(...) pack_items_(ISIS_MT_IPV4_UNICAST, __VA_ARGS__)
/* Functions related to subtlvs */
static struct isis_subtlvs *isis_alloc_subtlvs(void)
static struct isis_subtlvs *isis_alloc_subtlvs(enum isis_tlv_context context)
{
struct isis_subtlvs *result;
result = XCALLOC(MTYPE_ISIS_SUBTLV, sizeof(*result));
result->context = context;
init_item_list(&result->prefix_sids);
return result;
}
@ -217,6 +344,11 @@ static struct isis_subtlvs *copy_subtlvs(struct isis_subtlvs *subtlvs)
struct isis_subtlvs *rv = XCALLOC(MTYPE_ISIS_SUBTLV, sizeof(*rv));
rv->context = subtlvs->context;
copy_items(subtlvs->context, ISIS_SUBTLV_PREFIX_SID,
&subtlvs->prefix_sids, &rv->prefix_sids);
rv->source_prefix =
copy_subtlv_ipv6_source_prefix(subtlvs->source_prefix);
return rv;
@ -225,6 +357,9 @@ static struct isis_subtlvs *copy_subtlvs(struct isis_subtlvs *subtlvs)
static void format_subtlvs(struct isis_subtlvs *subtlvs, struct sbuf *buf,
int indent)
{
format_items(subtlvs->context, ISIS_SUBTLV_PREFIX_SID,
&subtlvs->prefix_sids, buf, indent);
format_subtlv_ipv6_source_prefix(subtlvs->source_prefix, buf, indent);
}
@ -233,6 +368,9 @@ static void isis_free_subtlvs(struct isis_subtlvs *subtlvs)
if (!subtlvs)
return;
free_items(subtlvs->context, ISIS_SUBTLV_PREFIX_SID,
&subtlvs->prefix_sids);
XFREE(MTYPE_ISIS_SUBTLV, subtlvs->source_prefix);
XFREE(MTYPE_ISIS_SUBTLV, subtlvs);
@ -248,6 +386,11 @@ static int pack_subtlvs(struct isis_subtlvs *subtlvs, struct stream *s)
stream_putc(s, 0); /* Put 0 as subtlvs length, filled in later */
rv = pack_items(subtlvs->context, ISIS_SUBTLV_PREFIX_SID,
&subtlvs->prefix_sids, s, NULL, NULL, NULL, NULL);
if (rv)
return rv;
rv = pack_subtlv_ipv6_source_prefix(subtlvs->source_prefix, s);
if (rv)
return rv;
@ -1135,6 +1278,7 @@ static void free_item_extended_ip_reach(struct isis_item *i)
{
struct isis_extended_ip_reach *item =
(struct isis_extended_ip_reach *)i;
isis_free_subtlvs(item->subtlvs);
XFREE(MTYPE_ISIS_TLV, item);
}
@ -1149,11 +1293,16 @@ static int pack_item_extended_ip_reach(struct isis_item *i, struct stream *s)
control = r->down ? ISIS_EXTENDED_IP_REACH_DOWN : 0;
control |= r->prefix.prefixlen;
control |= r->subtlvs ? ISIS_EXTENDED_IP_REACH_SUBTLV : 0;
stream_putc(s, control);
if (STREAM_WRITEABLE(s) < (unsigned)PSIZE(r->prefix.prefixlen))
return 1;
stream_put(s, &r->prefix.prefix.s_addr, PSIZE(r->prefix.prefixlen));
if (r->subtlvs)
return pack_subtlvs(r->subtlvs, s);
return 0;
}
@ -1235,9 +1384,12 @@ static int unpack_item_extended_ip_reach(uint16_t mtid, uint8_t len,
len - 6 - PSIZE(rv->prefix.prefixlen));
goto out;
}
sbuf_push(log, indent, "Skipping %" PRIu8 " bytes of subvls",
subtlv_len);
stream_forward_getp(s, subtlv_len);
rv->subtlvs = isis_alloc_subtlvs(ISIS_CONTEXT_SUBTLV_IP_REACH);
if (unpack_tlvs(ISIS_CONTEXT_SUBTLV_IP_REACH, subtlv_len, s,
log, rv->subtlvs, indent + 4)) {
goto out;
}
}
append_item(items, (struct isis_item *)rv);
@ -1712,7 +1864,7 @@ static int unpack_item_ipv6_reach(uint16_t mtid, uint8_t len, struct stream *s,
goto out;
}
rv->subtlvs = isis_alloc_subtlvs();
rv->subtlvs = isis_alloc_subtlvs(ISIS_CONTEXT_SUBTLV_IPV6_REACH);
if (unpack_tlvs(ISIS_CONTEXT_SUBTLV_IPV6_REACH, subtlv_len, s,
log, rv->subtlvs, indent + 4)) {
goto out;
@ -1890,7 +2042,6 @@ static void format_items_(uint16_t mtid, enum isis_tlv_context context,
for (i = items->head; i; i = i->next)
format_item(mtid, context, type, i, buf, indent);
}
#define format_items(...) format_items_(ISIS_MT_IPV4_UNICAST, __VA_ARGS__)
static void free_item(enum isis_tlv_context tlv_context,
enum isis_tlv_type tlv_type, struct isis_item *item)
@ -1996,6 +2147,14 @@ top:
break;
}
/* Multiple prefix-sids don't go into one TLV, so always break */
if (type == ISIS_SUBTLV_PREFIX_SID
&& (context == ISIS_CONTEXT_SUBTLV_IP_REACH
|| context == ISIS_CONTEXT_SUBTLV_IPV6_REACH)) {
item = item->next;
break;
}
if (len > 255) {
if (!last_len) /* strange, not a single item fit */
return 1;
@ -2800,6 +2959,9 @@ int isis_unpack_tlvs(size_t avail_len, struct stream *stream,
.name = _desc_, .unpack = unpack_subtlv_##_name_, \
}
#define ITEM_SUBTLV_OPS(_name_, _desc_) \
ITEM_TLV_OPS(_name_, _desc_)
ITEM_TLV_OPS(area_address, "TLV 1 Area Addresses");
ITEM_TLV_OPS(oldstyle_reach, "TLV 2 IS Reachability");
ITEM_TLV_OPS(lan_neighbor, "TLV 6 LAN Neighbors");
@ -2818,6 +2980,7 @@ TLV_OPS(threeway_adj, "TLV 240 P2P Three-Way Adjacency");
ITEM_TLV_OPS(ipv6_address, "TLV 232 IPv6 Interface Address");
ITEM_TLV_OPS(ipv6_reach, "TLV 236 IPv6 Reachability");
ITEM_SUBTLV_OPS(prefix_sid, "Sub-TLV 3 SR Prefix-SID");
SUBTLV_OPS(ipv6_source_prefix, "Sub-TLV 22 IPv6 Source Prefix");
static const struct tlv_ops *tlv_table[ISIS_CONTEXT_MAX][ISIS_TLV_MAX] = {
@ -2845,8 +3008,11 @@ static const struct tlv_ops *tlv_table[ISIS_CONTEXT_MAX][ISIS_TLV_MAX] = {
[ISIS_TLV_MT_IPV6_REACH] = &tlv_ipv6_reach_ops,
},
[ISIS_CONTEXT_SUBTLV_NE_REACH] = {},
[ISIS_CONTEXT_SUBTLV_IP_REACH] = {},
[ISIS_CONTEXT_SUBTLV_IP_REACH] = {
[ISIS_SUBTLV_PREFIX_SID] = &tlv_prefix_sid_ops,
},
[ISIS_CONTEXT_SUBTLV_IPV6_REACH] = {
[ISIS_SUBTLV_PREFIX_SID] = &tlv_prefix_sid_ops,
[ISIS_SUBTLV_IPV6_SOURCE_PREFIX] = &subtlv_ipv6_source_prefix_ops,
}
};
@ -3318,7 +3484,7 @@ void isis_tlvs_add_ipv6_dstsrc_reach(struct isis_tlvs *tlvs, uint16_t mtid,
mtid);
struct isis_ipv6_reach *r = (struct isis_ipv6_reach*)last_item(l);
r->subtlvs = isis_alloc_subtlvs();
r->subtlvs = isis_alloc_subtlvs(ISIS_CONTEXT_SUBTLV_IPV6_REACH);
r->subtlvs->source_prefix = XCALLOC(MTYPE_ISIS_SUBTLV, sizeof(*src));
memcpy(r->subtlvs->source_prefix, src, sizeof(*src));
}

30
isisd/isis_tlvs.h
View File

@ -83,6 +83,8 @@ struct isis_extended_ip_reach {
uint32_t metric;
bool down;
struct prefix_ipv4 prefix;
struct isis_subtlvs *subtlvs;
};
struct isis_ipv6_reach;
@ -219,9 +221,21 @@ struct isis_tlvs {
struct isis_spine_leaf *spine_leaf;
};
struct isis_subtlvs {
/* draft-baker-ipv6-isis-dst-src-routing-06 */
struct prefix_ipv6 *source_prefix;
#define ISIS_PREFIX_SID_READVERTISED 0x80
#define ISIS_PREFIX_SID_NODE 0x40
#define ISIS_PREFIX_SID_NO_PHP 0x20
#define ISIS_PREFIX_SID_EXPLICIT_NULL 0x10
#define ISIS_PREFIX_SID_VALUE 0x08
#define ISIS_PREFIX_SID_LOCAL 0x04
struct isis_prefix_sid;
struct isis_prefix_sid {
struct isis_prefix_sid *next;
uint8_t flags;
uint8_t algorithm;
uint32_t value;
};
enum isis_tlv_context {
@ -232,6 +246,15 @@ enum isis_tlv_context {
ISIS_CONTEXT_MAX
};
struct isis_subtlvs {
enum isis_tlv_context context;
/* draft-baker-ipv6-isis-dst-src-routing-06 */
struct prefix_ipv6 *source_prefix;
/* draft-ietf-isis-segment-routing-extensions-16 */
struct isis_item_list prefix_sids;
};
enum isis_tlv_type {
ISIS_TLV_AREA_ADDRESSES = 1,
ISIS_TLV_OLDSTYLE_REACH = 2,
@ -258,6 +281,7 @@ enum isis_tlv_type {
ISIS_TLV_THREE_WAY_ADJ = 240,
ISIS_TLV_MAX = 256,
ISIS_SUBTLV_PREFIX_SID = 3,
ISIS_SUBTLV_IPV6_SOURCE_PREFIX = 22
};