mirror of
https://github.com/torvalds/linux
synced 2024-09-20 11:07:02 +00:00
seg6: add NEXT-C-SID support for SRv6 End behavior
The NEXT-C-SID mechanism described in [1] offers the possibility of
encoding several SRv6 segments within a single 128 bit SID address. Such
a SID address is called a Compressed SID (C-SID) container. In this way,
the length of the SID List can be drastically reduced.
A SID instantiated with the NEXT-C-SID flavor considers an IPv6 address
logically structured in three main blocks: i) Locator-Block; ii)
Locator-Node Function; iii) Argument.
C-SID container
+------------------------------------------------------------------+
| Locator-Block |Loc-Node| Argument |
| |Function| |
+------------------------------------------------------------------+
<--------- B -----------> <- NF -> <------------- A --------------->
(i) The Locator-Block can be any IPv6 prefix available to the provider;
(ii) The Locator-Node Function represents the node and the function to
be triggered when a packet is received on the node;
(iii) The Argument carries the remaining C-SIDs in the current C-SID
container.
The NEXT-C-SID mechanism relies on the "flavors" framework defined in
[2]. The flavors represent additional operations that can modify or
extend a subset of the existing behaviors.
This patch introduces the support for flavors in SRv6 End behavior
implementing the NEXT-C-SID one. An SRv6 End behavior with NEXT-C-SID
flavor works as an End behavior but it is capable of processing the
compressed SID List encoded in C-SID containers.
An SRv6 End behavior with NEXT-C-SID flavor can be configured to support
user-provided Locator-Block and Locator-Node Function lengths. In this
implementation, such lengths must be evenly divisible by 8 (i.e. must be
byte-aligned), otherwise the kernel informs the user about invalid
values with a meaningful error code and message through netlink_ext_ack.
If Locator-Block and/or Locator-Node Function lengths are not provided
by the user during configuration of an SRv6 End behavior instance with
NEXT-C-SID flavor, the kernel will choose their default values i.e.,
32-bit Locator-Block and 16-bit Locator-Node Function.
[1] - https://datatracker.ietf.org/doc/html/draft-ietf-spring-srv6-srh-compression
[2] - https://datatracker.ietf.org/doc/html/rfc8986
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Andrea Mayer
Paolo Abeni
parent
e2a8ecc451
commit
848f3c0d47
|
|
@ -28,6 +28,7 @@ enum {
|
|||
SEG6_LOCAL_BPF,
|
||||
SEG6_LOCAL_VRFTABLE,
|
||||
SEG6_LOCAL_COUNTERS,
|
||||
SEG6_LOCAL_FLAVORS,
|
||||
__SEG6_LOCAL_MAX,
|
||||
};
|
||||
#define SEG6_LOCAL_MAX (__SEG6_LOCAL_MAX - 1)
|
||||
|
|
@ -110,4 +111,27 @@ enum {
|
|||
|
||||
#define SEG6_LOCAL_CNT_MAX (__SEG6_LOCAL_CNT_MAX - 1)
|
||||
|
||||
/* SRv6 End* Flavor attributes */
|
||||
enum {
|
||||
SEG6_LOCAL_FLV_UNSPEC,
|
||||
SEG6_LOCAL_FLV_OPERATION,
|
||||
SEG6_LOCAL_FLV_LCBLOCK_BITS,
|
||||
SEG6_LOCAL_FLV_LCNODE_FN_BITS,
|
||||
__SEG6_LOCAL_FLV_MAX,
|
||||
};
|
||||
|
||||
#define SEG6_LOCAL_FLV_MAX (__SEG6_LOCAL_FLV_MAX - 1)
|
||||
|
||||
/* Designed flavor operations for SRv6 End* Behavior */
|
||||
enum {
|
||||
SEG6_LOCAL_FLV_OP_UNSPEC,
|
||||
SEG6_LOCAL_FLV_OP_PSP,
|
||||
SEG6_LOCAL_FLV_OP_USP,
|
||||
SEG6_LOCAL_FLV_OP_USD,
|
||||
SEG6_LOCAL_FLV_OP_NEXT_CSID,
|
||||
__SEG6_LOCAL_FLV_OP_MAX
|
||||
};
|
||||
|
||||
#define SEG6_LOCAL_FLV_OP_MAX (__SEG6_LOCAL_FLV_OP_MAX - 1)
|
||||
|
||||
#endif
|
||||
|
|
|
|||
|
|
@ -73,6 +73,55 @@ struct bpf_lwt_prog {
|
|||
char *name;
|
||||
};
|
||||
|
||||
/* default length values (expressed in bits) for both Locator-Block and
|
||||
* Locator-Node Function.
|
||||
*
|
||||
* Both SEG6_LOCAL_LCBLOCK_DBITS and SEG6_LOCAL_LCNODE_FN_DBITS *must* be:
|
||||
* i) greater than 0;
|
||||
* ii) evenly divisible by 8. In other terms, the lengths of the
|
||||
* Locator-Block and Locator-Node Function must be byte-aligned (we can
|
||||
* relax this constraint in the future if really needed).
|
||||
*
|
||||
* Moreover, a third condition must hold:
|
||||
* iii) SEG6_LOCAL_LCBLOCK_DBITS + SEG6_LOCAL_LCNODE_FN_DBITS <= 128.
|
||||
*
|
||||
* The correctness of SEG6_LOCAL_LCBLOCK_DBITS and SEG6_LOCAL_LCNODE_FN_DBITS
|
||||
* values are checked during the kernel compilation. If the compilation stops,
|
||||
* check the value of these parameters to see if they meet conditions (i), (ii)
|
||||
* and (iii).
|
||||
*/
|
||||
#define SEG6_LOCAL_LCBLOCK_DBITS 32
|
||||
#define SEG6_LOCAL_LCNODE_FN_DBITS 16
|
||||
|
||||
/* The following next_csid_chk_{cntr,lcblock,lcblock_fn}_bits macros can be
|
||||
* used directly to check whether the lengths (in bits) of Locator-Block and
|
||||
* Locator-Node Function are valid according to (i), (ii), (iii).
|
||||
*/
|
||||
#define next_csid_chk_cntr_bits(blen, flen) \
|
||||
((blen) + (flen) > 128)
|
||||
|
||||
#define next_csid_chk_lcblock_bits(blen) \
|
||||
({ \
|
||||
typeof(blen) __tmp = blen; \
|
||||
(!__tmp || __tmp > 120 || (__tmp & 0x07)); \
|
||||
})
|
||||
|
||||
#define next_csid_chk_lcnode_fn_bits(flen) \
|
||||
next_csid_chk_lcblock_bits(flen)
|
||||
|
||||
/* Supported Flavor operations are reported in this bitmask */
|
||||
#define SEG6_LOCAL_FLV_SUPP_OPS (BIT(SEG6_LOCAL_FLV_OP_NEXT_CSID))
|
||||
|
||||
struct seg6_flavors_info {
|
||||
/* Flavor operations */
|
||||
__u32 flv_ops;
|
||||
|
||||
/* Locator-Block length, expressed in bits */
|
||||
__u8 lcblock_bits;
|
||||
/* Locator-Node Function length, expressed in bits*/
|
||||
__u8 lcnode_func_bits;
|
||||
};
|
||||
|
||||
enum seg6_end_dt_mode {
|
||||
DT_INVALID_MODE = -EINVAL,
|
||||
DT_LEGACY_MODE = 0,
|
||||
|
|
@ -136,6 +185,8 @@ struct seg6_local_lwt {
|
|||
#ifdef CONFIG_NET_L3_MASTER_DEV
|
||||
struct seg6_end_dt_info dt_info;
|
||||
#endif
|
||||
struct seg6_flavors_info flv_info;
|
||||
|
||||
struct pcpu_seg6_local_counters __percpu *pcpu_counters;
|
||||
|
||||
int headroom;
|
||||
|
|
@ -271,8 +322,50 @@ int seg6_lookup_nexthop(struct sk_buff *skb,
|
|||
return seg6_lookup_any_nexthop(skb, nhaddr, tbl_id, false);
|
||||
}
|
||||
|
||||
/* regular endpoint function */
|
||||
static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
|
||||
static __u8 seg6_flv_lcblock_octects(const struct seg6_flavors_info *finfo)
|
||||
{
|
||||
return finfo->lcblock_bits >> 3;
|
||||
}
|
||||
|
||||
static __u8 seg6_flv_lcnode_func_octects(const struct seg6_flavors_info *finfo)
|
||||
{
|
||||
return finfo->lcnode_func_bits >> 3;
|
||||
}
|
||||
|
||||
static bool seg6_next_csid_is_arg_zero(const struct in6_addr *addr,
|
||||
const struct seg6_flavors_info *finfo)
|
||||
{
|
||||
__u8 fnc_octects = seg6_flv_lcnode_func_octects(finfo);
|
||||
__u8 blk_octects = seg6_flv_lcblock_octects(finfo);
|
||||
__u8 arg_octects;
|
||||
int i;
|
||||
|
||||
arg_octects = 16 - blk_octects - fnc_octects;
|
||||
for (i = 0; i < arg_octects; ++i) {
|
||||
if (addr->s6_addr[blk_octects + fnc_octects + i] != 0x00)
|
||||
return false;
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
/* assume that DA.Argument length > 0 */
|
||||
static void seg6_next_csid_advance_arg(struct in6_addr *addr,
|
||||
const struct seg6_flavors_info *finfo)
|
||||
{
|
||||
__u8 fnc_octects = seg6_flv_lcnode_func_octects(finfo);
|
||||
__u8 blk_octects = seg6_flv_lcblock_octects(finfo);
|
||||
|
||||
/* advance DA.Argument */
|
||||
memmove(&addr->s6_addr[blk_octects],
|
||||
&addr->s6_addr[blk_octects + fnc_octects],
|
||||
16 - blk_octects - fnc_octects);
|
||||
|
||||
memset(&addr->s6_addr[16 - fnc_octects], 0x00, fnc_octects);
|
||||
}
|
||||
|
||||
static int input_action_end_core(struct sk_buff *skb,
|
||||
struct seg6_local_lwt *slwt)
|
||||
{
|
||||
struct ipv6_sr_hdr *srh;
|
||||
|
||||
|
|
@ -291,6 +384,38 @@ static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
|
|||
return -EINVAL;
|
||||
}
|
||||
|
||||
static int end_next_csid_core(struct sk_buff *skb, struct seg6_local_lwt *slwt)
|
||||
{
|
||||
const struct seg6_flavors_info *finfo = &slwt->flv_info;
|
||||
struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
|
||||
|
||||
if (seg6_next_csid_is_arg_zero(daddr, finfo))
|
||||
return input_action_end_core(skb, slwt);
|
||||
|
||||
/* update DA */
|
||||
seg6_next_csid_advance_arg(daddr, finfo);
|
||||
|
||||
seg6_lookup_nexthop(skb, NULL, 0);
|
||||
|
||||
return dst_input(skb);
|
||||
}
|
||||
|
||||
static bool seg6_next_csid_enabled(__u32 fops)
|
||||
{
|
||||
return fops & BIT(SEG6_LOCAL_FLV_OP_NEXT_CSID);
|
||||
}
|
||||
|
||||
/* regular endpoint function */
|
||||
static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
|
||||
{
|
||||
const struct seg6_flavors_info *finfo = &slwt->flv_info;
|
||||
|
||||
if (seg6_next_csid_enabled(finfo->flv_ops))
|
||||
return end_next_csid_core(skb, slwt);
|
||||
|
||||
return input_action_end_core(skb, slwt);
|
||||
}
|
||||
|
||||
/* regular endpoint, and forward to specified nexthop */
|
||||
static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt)
|
||||
{
|
||||
|
|
@ -951,7 +1076,8 @@ static struct seg6_action_desc seg6_action_table[] = {
|
|||
{
|
||||
.action = SEG6_LOCAL_ACTION_END,
|
||||
.attrs = 0,
|
||||
.optattrs = SEG6_F_LOCAL_COUNTERS,
|
||||
.optattrs = SEG6_F_LOCAL_COUNTERS |
|
||||
SEG6_F_ATTR(SEG6_LOCAL_FLAVORS),
|
||||
.input = input_action_end,
|
||||
},
|
||||
{
|
||||
|
|
@ -1132,6 +1258,7 @@ static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
|
|||
[SEG6_LOCAL_OIF] = { .type = NLA_U32 },
|
||||
[SEG6_LOCAL_BPF] = { .type = NLA_NESTED },
|
||||
[SEG6_LOCAL_COUNTERS] = { .type = NLA_NESTED },
|
||||
[SEG6_LOCAL_FLAVORS] = { .type = NLA_NESTED },
|
||||
};
|
||||
|
||||
static int parse_nla_srh(struct nlattr **attrs, struct seg6_local_lwt *slwt,
|
||||
|
|
@ -1551,6 +1678,192 @@ static void destroy_attr_counters(struct seg6_local_lwt *slwt)
|
|||
free_percpu(slwt->pcpu_counters);
|
||||
}
|
||||
|
||||
static const
|
||||
struct nla_policy seg6_local_flavors_policy[SEG6_LOCAL_FLV_MAX + 1] = {
|
||||
[SEG6_LOCAL_FLV_OPERATION] = { .type = NLA_U32 },
|
||||
[SEG6_LOCAL_FLV_LCBLOCK_BITS] = { .type = NLA_U8 },
|
||||
[SEG6_LOCAL_FLV_LCNODE_FN_BITS] = { .type = NLA_U8 },
|
||||
};
|
||||
|
||||
/* check whether the lengths of the Locator-Block and Locator-Node Function
|
||||
* are compatible with the dimension of a C-SID container.
|
||||
*/
|
||||
static int seg6_chk_next_csid_cfg(__u8 block_len, __u8 func_len)
|
||||
{
|
||||
/* Locator-Block and Locator-Node Function cannot exceed 128 bits
|
||||
* (i.e. C-SID container lenghts).
|
||||
*/
|
||||
if (next_csid_chk_cntr_bits(block_len, func_len))
|
||||
return -EINVAL;
|
||||
|
||||
/* Locator-Block length must be greater than zero and evenly divisible
|
||||
* by 8. There must be room for a Locator-Node Function, at least.
|
||||
*/
|
||||
if (next_csid_chk_lcblock_bits(block_len))
|
||||
return -EINVAL;
|
||||
|
||||
/* Locator-Node Function length must be greater than zero and evenly
|
||||
* divisible by 8. There must be room for the Locator-Block.
|
||||
*/
|
||||
if (next_csid_chk_lcnode_fn_bits(func_len))
|
||||
return -EINVAL;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int seg6_parse_nla_next_csid_cfg(struct nlattr **tb,
|
||||
struct seg6_flavors_info *finfo,
|
||||
struct netlink_ext_ack *extack)
|
||||
{
|
||||
__u8 func_len = SEG6_LOCAL_LCNODE_FN_DBITS;
|
||||
__u8 block_len = SEG6_LOCAL_LCBLOCK_DBITS;
|
||||
int rc;
|
||||
|
||||
if (tb[SEG6_LOCAL_FLV_LCBLOCK_BITS])
|
||||
block_len = nla_get_u8(tb[SEG6_LOCAL_FLV_LCBLOCK_BITS]);
|
||||
|
||||
if (tb[SEG6_LOCAL_FLV_LCNODE_FN_BITS])
|
||||
func_len = nla_get_u8(tb[SEG6_LOCAL_FLV_LCNODE_FN_BITS]);
|
||||
|
||||
rc = seg6_chk_next_csid_cfg(block_len, func_len);
|
||||
if (rc < 0) {
|
||||
NL_SET_ERR_MSG(extack,
|
||||
"Invalid Locator Block/Node Function lengths");
|
||||
return rc;
|
||||
}
|
||||
|
||||
finfo->lcblock_bits = block_len;
|
||||
finfo->lcnode_func_bits = func_len;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int parse_nla_flavors(struct nlattr **attrs, struct seg6_local_lwt *slwt,
|
||||
struct netlink_ext_ack *extack)
|
||||
{
|
||||
struct seg6_flavors_info *finfo = &slwt->flv_info;
|
||||
struct nlattr *tb[SEG6_LOCAL_FLV_MAX + 1];
|
||||
unsigned long fops;
|
||||
int rc;
|
||||
|
||||
rc = nla_parse_nested_deprecated(tb, SEG6_LOCAL_FLV_MAX,
|
||||
attrs[SEG6_LOCAL_FLAVORS],
|
||||
seg6_local_flavors_policy, NULL);
|
||||
if (rc < 0)
|
||||
return rc;
|
||||
|
||||
/* this attribute MUST always be present since it represents the Flavor
|
||||
* operation(s) to be carried out.
|
||||
*/
|
||||
if (!tb[SEG6_LOCAL_FLV_OPERATION])
|
||||
return -EINVAL;
|
||||
|
||||
fops = nla_get_u32(tb[SEG6_LOCAL_FLV_OPERATION]);
|
||||
if (fops & ~SEG6_LOCAL_FLV_SUPP_OPS) {
|
||||
NL_SET_ERR_MSG(extack, "Unsupported Flavor operation(s)");
|
||||
return -EOPNOTSUPP;
|
||||
}
|
||||
|
||||
finfo->flv_ops = fops;
|
||||
|
||||
if (seg6_next_csid_enabled(fops)) {
|
||||
/* Locator-Block and Locator-Node Function lengths can be
|
||||
* provided by the user space. Otherwise, default values are
|
||||
* applied.
|
||||
*/
|
||||
rc = seg6_parse_nla_next_csid_cfg(tb, finfo, extack);
|
||||
if (rc < 0)
|
||||
return rc;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int seg6_fill_nla_next_csid_cfg(struct sk_buff *skb,
|
||||
struct seg6_flavors_info *finfo)
|
||||
{
|
||||
if (nla_put_u8(skb, SEG6_LOCAL_FLV_LCBLOCK_BITS, finfo->lcblock_bits))
|
||||
return -EMSGSIZE;
|
||||
|
||||
if (nla_put_u8(skb, SEG6_LOCAL_FLV_LCNODE_FN_BITS,
|
||||
finfo->lcnode_func_bits))
|
||||
return -EMSGSIZE;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int put_nla_flavors(struct sk_buff *skb, struct seg6_local_lwt *slwt)
|
||||
{
|
||||
struct seg6_flavors_info *finfo = &slwt->flv_info;
|
||||
__u32 fops = finfo->flv_ops;
|
||||
struct nlattr *nest;
|
||||
int rc;
|
||||
|
||||
nest = nla_nest_start(skb, SEG6_LOCAL_FLAVORS);
|
||||
if (!nest)
|
||||
return -EMSGSIZE;
|
||||
|
||||
if (nla_put_u32(skb, SEG6_LOCAL_FLV_OPERATION, fops)) {
|
||||
rc = -EMSGSIZE;
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (seg6_next_csid_enabled(fops)) {
|
||||
rc = seg6_fill_nla_next_csid_cfg(skb, finfo);
|
||||
if (rc < 0)
|
||||
goto err;
|
||||
}
|
||||
|
||||
return nla_nest_end(skb, nest);
|
||||
|
||||
err:
|
||||
nla_nest_cancel(skb, nest);
|
||||
return rc;
|
||||
}
|
||||
|
||||
static int seg6_cmp_nla_next_csid_cfg(struct seg6_flavors_info *finfo_a,
|
||||
struct seg6_flavors_info *finfo_b)
|
||||
{
|
||||
if (finfo_a->lcblock_bits != finfo_b->lcblock_bits)
|
||||
return 1;
|
||||
|
||||
if (finfo_a->lcnode_func_bits != finfo_b->lcnode_func_bits)
|
||||
return 1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int cmp_nla_flavors(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
|
||||
{
|
||||
struct seg6_flavors_info *finfo_a = &a->flv_info;
|
||||
struct seg6_flavors_info *finfo_b = &b->flv_info;
|
||||
|
||||
if (finfo_a->flv_ops != finfo_b->flv_ops)
|
||||
return 1;
|
||||
|
||||
if (seg6_next_csid_enabled(finfo_a->flv_ops)) {
|
||||
if (seg6_cmp_nla_next_csid_cfg(finfo_a, finfo_b))
|
||||
return 1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int encap_size_flavors(struct seg6_local_lwt *slwt)
|
||||
{
|
||||
struct seg6_flavors_info *finfo = &slwt->flv_info;
|
||||
int nlsize;
|
||||
|
||||
nlsize = nla_total_size(0) + /* nest SEG6_LOCAL_FLAVORS */
|
||||
nla_total_size(4); /* SEG6_LOCAL_FLV_OPERATION */
|
||||
|
||||
if (seg6_next_csid_enabled(finfo->flv_ops))
|
||||
nlsize += nla_total_size(1) + /* SEG6_LOCAL_FLV_LCBLOCK_BITS */
|
||||
nla_total_size(1); /* SEG6_LOCAL_FLV_LCNODE_FN_BITS */
|
||||
|
||||
return nlsize;
|
||||
}
|
||||
|
||||
struct seg6_action_param {
|
||||
int (*parse)(struct nlattr **attrs, struct seg6_local_lwt *slwt,
|
||||
struct netlink_ext_ack *extack);
|
||||
|
|
@ -1603,6 +1916,10 @@ static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
|
|||
.put = put_nla_counters,
|
||||
.cmp = cmp_nla_counters,
|
||||
.destroy = destroy_attr_counters },
|
||||
|
||||
[SEG6_LOCAL_FLAVORS] = { .parse = parse_nla_flavors,
|
||||
.put = put_nla_flavors,
|
||||
.cmp = cmp_nla_flavors },
|
||||
};
|
||||
|
||||
/* call the destroy() callback (if available) for each set attribute in
|
||||
|
|
@ -1916,6 +2233,9 @@ static int seg6_local_get_encap_size(struct lwtunnel_state *lwt)
|
|||
/* SEG6_LOCAL_CNT_ERRORS */
|
||||
nla_total_size_64bit(sizeof(__u64));
|
||||
|
||||
if (attrs & SEG6_F_ATTR(SEG6_LOCAL_FLAVORS))
|
||||
nlsize += encap_size_flavors(slwt);
|
||||
|
||||
return nlsize;
|
||||
}
|
||||
|
||||
|
|
@ -1971,6 +2291,15 @@ int __init seg6_local_init(void)
|
|||
*/
|
||||
BUILD_BUG_ON(SEG6_LOCAL_MAX + 1 > BITS_PER_TYPE(unsigned long));
|
||||
|
||||
/* If the default NEXT-C-SID Locator-Block/Node Function lengths (in
|
||||
* bits) have been changed with invalid values, kernel build stops
|
||||
* here.
|
||||
*/
|
||||
BUILD_BUG_ON(next_csid_chk_cntr_bits(SEG6_LOCAL_LCBLOCK_DBITS,
|
||||
SEG6_LOCAL_LCNODE_FN_DBITS));
|
||||
BUILD_BUG_ON(next_csid_chk_lcblock_bits(SEG6_LOCAL_LCBLOCK_DBITS));
|
||||
BUILD_BUG_ON(next_csid_chk_lcnode_fn_bits(SEG6_LOCAL_LCNODE_FN_DBITS));
|
||||
|
||||
return lwtunnel_encap_add_ops(&seg6_local_ops,
|
||||
LWTUNNEL_ENCAP_SEG6_LOCAL);
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue