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netlink: add snl(3) support for parsing unknown-size arrays

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Reviewed by:	bapt
Differential Review: https://reviews.freebsd.org/D40282
MFC after:	2 weeks
This commit is contained in:
Alexander V. Chernikov 2023-05-27 11:09:01 +00:00
parent 99ea21744b
commit 5f19f790b3
2 changed files with 117 additions and 26 deletions
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124
sys/netlink/netlink_snl.h
View File

@ -149,33 +149,40 @@ struct snl_attr_parser {
typedef bool snl_parse_post_f(struct snl_state *ss, void *target);
struct snl_hdr_parser {
int hdr_off; /* aligned header size */
int fp_size;
int np_size;
uint16_t in_hdr_size; /* Input header size */
uint16_t out_size; /* Output structure size */
uint16_t fp_size; /* Number of items in field parser */
uint16_t np_size; /* Number of items in attribute parser */
const struct snl_field_parser *fp; /* array of header field parsers */
const struct snl_attr_parser *np; /* array of attribute parsers */
snl_parse_post_f *cb_post; /* post-parse callback */
};
#define SNL_DECLARE_PARSER_EXT(_name, _t, _fp, _np, _cb) \
static const struct snl_hdr_parser _name = { \
.hdr_off = sizeof(_t), \
.fp = &((_fp)[0]), \
.np = &((_np)[0]), \
.fp_size = NL_ARRAY_LEN(_fp), \
.np_size = NL_ARRAY_LEN(_np), \
.cb_post = _cb, \
#define SNL_DECLARE_PARSER_EXT(_name, _sz_h_in, _sz_out, _fp, _np, _cb) \
static const struct snl_hdr_parser _name = { \
.in_hdr_size = _sz_h_in, \
.out_size = _sz_out, \
.fp = &((_fp)[0]), \
.np = &((_np)[0]), \
.fp_size = NL_ARRAY_LEN(_fp), \
.np_size = NL_ARRAY_LEN(_np), \
.cb_post = _cb, \
}
#define SNL_DECLARE_PARSER(_name, _t, _fp, _np) \
SNL_DECLARE_PARSER_EXT(_name, _t, _fp, _np, NULL)
#define SNL_DECLARE_PARSER(_name, _t, _fp, _np) \
SNL_DECLARE_PARSER_EXT(_name, sizeof(_t), 0, _fp, _np, NULL)
#define SNL_DECLARE_ATTR_PARSER(_name, _np) \
static const struct snl_hdr_parser _name = { \
.np = &((_np)[0]), \
.np_size = NL_ARRAY_LEN(_np), \
#define SNL_DECLARE_ATTR_PARSER_EXT(_name, _sz_out, _np, _cb) \
static const struct snl_hdr_parser _name = { \
.out_size = _sz_out, \
.np = &((_np)[0]), \
.np_size = NL_ARRAY_LEN(_np), \
.cb_post = _cb, \
}
#define SNL_DECLARE_ATTR_PARSER(_name, _np) \
SNL_DECLARE_ATTR_PARSER_EXT(_name, 0, _np, NULL)
static inline void *
snl_allocz(struct snl_state *ss, int len)
@ -471,11 +478,13 @@ static inline bool
snl_parse_header(struct snl_state *ss, void *hdr, int len,
const struct snl_hdr_parser *parser, void *target)
{
/* Extract fields first (if any) */
snl_parse_fields(ss, hdr, parser->hdr_off, parser->fp, parser->fp_size, target);
struct nlattr *nla_head;
struct nlattr *nla_head = (struct nlattr *)(void *)((char *)hdr + parser->hdr_off);
bool result = snl_parse_attrs_raw(ss, nla_head, len - parser->hdr_off,
/* Extract fields first (if any) */
snl_parse_fields(ss, hdr, parser->in_hdr_size, parser->fp, parser->fp_size, target);
nla_head = (struct nlattr *)(void *)((char *)hdr + parser->in_hdr_size);
bool result = snl_parse_attrs_raw(ss, nla_head, len - parser->in_hdr_size,
parser->np, parser->np_size, target);
if (result && parser->cb_post != NULL)
@ -642,6 +651,78 @@ snl_attr_get_nested(struct snl_state *ss, struct nlattr *nla, const void *arg, v
return (snl_parse_header(ss, NLA_DATA(nla), NLA_DATA_LEN(nla), p, target));
}
struct snl_parray {
uint32_t count;
void **items;
};
static inline bool
snl_attr_get_parray_sz(struct snl_state *ss, struct nlattr *container_nla,
uint32_t start_size, const void *arg, void *target)
{
const struct snl_hdr_parser *p = (const struct snl_hdr_parser *)arg;
struct snl_parray *array = target;
struct nlattr *nla;
uint32_t count = 0, size = start_size;
if (p->out_size == 0)
return (false);
array->items = snl_allocz(ss, size * sizeof(void *));
if (array->items == NULL)
return (false);
/*
* If the provided parser is an attribute parser, assume that each
* nla in the container nla is the container nla itself and parse
* the contents of this nla.
* Otherwise, run the parser on raw data, assuming the header of this
* data has u16 field with total size in the beginning.
*/
uint32_t data_off = 0;
if (p->in_hdr_size == 0)
data_off = sizeof(struct nlattr);
NLA_FOREACH(nla, NLA_DATA(container_nla), NLA_DATA_LEN(container_nla)) {
void *item = snl_allocz(ss, p->out_size);
if (item == NULL)
return (false);
void *data = (char *)(void *)nla + data_off;
int data_len = nla->nla_len - data_off;
if (!(snl_parse_header(ss, data, data_len, p, item)))
return (false);
if (count == size) {
uint32_t new_size = size * 2;
void **new_array = snl_allocz(ss, new_size *sizeof(void *));
memcpy(new_array, array->items, size * sizeof(void *));
array->items = new_array;
size = new_size;
}
array->items[count++] = item;
}
array->count = count;
return (true);
}
/*
* Parses and stores the unknown-size array.
* Assumes each array item is a container and the NLAs in the container are parsable
* by the parser provided in @arg.
* Assumes @target is struct snl_parray
*/
static inline bool
snl_attr_get_parray(struct snl_state *ss, struct nlattr *nla, const void *arg, void *target)
{
return (snl_attr_get_parray_sz(ss, nla, 8, arg, target));
}
static inline bool
snl_attr_get_nla(struct snl_state *ss __unused, struct nlattr *nla,
const void *arg __unused, void *target)
@ -878,6 +959,7 @@ snl_realloc_msg_buffer(struct snl_writer *nw, size_t sz)
memcpy(new_base, nw->base, nw->offset);
if (nw->hdr != NULL) {
int hdr_off = (char *)(nw->hdr) - nw->base;
nw->hdr = (struct nlmsghdr *)(void *)((char *)new_base + hdr_off);
}
nw->base = new_base;

19
sys/netlink/netlink_snl_route_parsers.h
View File

@ -85,7 +85,9 @@ _cb_p_mp_nh(struct snl_state *ss __unused, void *_target)
}
#undef _IN
#undef _OUT
SNL_DECLARE_PARSER_EXT(_mpath_nh_parser, struct rtnexthop, _fp_p_mp_nh, _nla_p_mp_nh, _cb_p_mp_nh);
SNL_DECLARE_PARSER_EXT(_mpath_nh_parser, sizeof(struct rtnexthop),
sizeof(struct rta_mpath_nh), _fp_p_mp_nh, _nla_p_mp_nh,
_cb_p_mp_nh);
struct rta_mpath {
int num_nhops;
@ -185,7 +187,9 @@ _cb_p_route(struct snl_state *ss __unused, void *_target)
}
#undef _IN
#undef _OUT
SNL_DECLARE_PARSER_EXT(snl_rtm_route_parser, struct rtmsg, _fp_p_route, _nla_p_route, _cb_p_route);
SNL_DECLARE_PARSER_EXT(snl_rtm_route_parser, sizeof(struct rtmsg),
sizeof(struct snl_parsed_route), _fp_p_route, _nla_p_route,
_cb_p_route);
/* RTM_<NEW|DEL|GET>LINK message parser */
struct snl_parsed_link {
@ -299,7 +303,9 @@ _cb_p_neigh(struct snl_state *ss __unused, void *_target)
}
#undef _IN
#undef _OUT
SNL_DECLARE_PARSER_EXT(snl_rtm_neigh_parser, struct ndmsg, _fp_p_neigh_s, _nla_p_neigh_s, _cb_p_neigh);
SNL_DECLARE_PARSER_EXT(snl_rtm_neigh_parser, sizeof(struct ndmsg),
sizeof(struct snl_parsed_neigh), _fp_p_neigh_s, _nla_p_neigh_s,
_cb_p_neigh);
struct snl_parsed_addr {
uint8_t ifa_family;
@ -347,7 +353,9 @@ _cb_p_addr(struct snl_state *ss __unused, void *_target)
}
#undef _IN
#undef _OUT
SNL_DECLARE_PARSER_EXT(snl_rtm_addr_parser, struct ifaddrmsg, _fp_p_addr_s, _nla_p_addr_s, _cb_p_addr);
SNL_DECLARE_PARSER_EXT(snl_rtm_addr_parser, sizeof(struct ifaddrmsg),
sizeof(struct snl_parsed_addr), _fp_p_addr_s, _nla_p_addr_s,
_cb_p_addr);
struct snl_parsed_nhop {
uint32_t nha_id;
@ -397,7 +405,8 @@ _cb_p_nh(struct snl_state *ss __unused, void *_target)
}
#undef _IN
#undef _OUT
SNL_DECLARE_PARSER_EXT(snl_nhmsg_parser, struct nhmsg, _fp_p_nh, _nla_p_nh, _cb_p_nh);
SNL_DECLARE_PARSER_EXT(snl_nhmsg_parser, sizeof(struct nhmsg),
sizeof(struct snl_parsed_nhop), _fp_p_nh, _nla_p_nh, _cb_p_nh);
static const struct snl_hdr_parser *snl_all_route_parsers[] = {
&_metrics_mp_nh_parser, &_mpath_nh_parser, &_metrics_parser, &snl_rtm_route_parser,