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sys/netlink/netlink_generic.c
- This file was added.
/*- | |||||
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD | |||||
* | |||||
* Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> | |||||
* | |||||
* Redistribution and use in source and binary forms, with or without | |||||
* modification, are permitted provided that the following conditions | |||||
* are met: | |||||
* 1. Redistributions of source code must retain the above copyright | |||||
* notice, this list of conditions and the following disclaimer. | |||||
* 2. Redistributions in binary form must reproduce the above copyright | |||||
* notice, this list of conditions and the following disclaimer in the | |||||
* documentation and/or other materials provided with the distribution. | |||||
* | |||||
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |||||
* SUCH DAMAGE. | |||||
*/ | |||||
#include <sys/cdefs.h> | |||||
__FBSDID("$FreeBSD$"); | |||||
#include <sys/types.h> | |||||
#include <sys/malloc.h> | |||||
#include <sys/priv.h> | |||||
#include <sys/socket.h> | |||||
#include <sys/ck.h> | |||||
#include <netlink/netlink.h> | |||||
#include <netlink/netlink_ctl.h> | |||||
#include <netlink/netlink_var.h> | |||||
#include <netlink/netlink_generic.h> | |||||
#define DEBUG_MOD_NAME nl_generic | |||||
#define DEBUG_MAX_LEVEL LOG_DEBUG3 | |||||
#include <netlink/netlink_debug.h> | |||||
_DECLARE_DEBUG(LOG_DEBUG3); | |||||
#define MAX_FAMILIES 20 | |||||
#define MAX_GROUPS 20 | |||||
#define MIN_GROUP_NUM 48 | |||||
static struct sx sx_lock; | |||||
#define GENL_LOCK_INIT() sx_init(&sx_lock, "genetlink lock") | |||||
#define GENL_LOCK_DESTROY() sx_destroy(&sx_lock) | |||||
#define GENL_LOCK() sx_xlock(&sx_lock) | |||||
#define GENL_UNLOCK() sx_xunlock(&sx_lock) | |||||
struct genl_family { | |||||
const char *family_name; | |||||
uint16_t family_hdrsize; | |||||
uint16_t family_id; | |||||
uint16_t family_version; | |||||
uint16_t family_attr_max; | |||||
uint16_t family_cmd_size; | |||||
uint16_t family_num_groups; | |||||
struct genl_cmd *family_cmds; | |||||
}; | |||||
static struct genl_family families[MAX_FAMILIES]; | |||||
struct genl_group { | |||||
struct genl_family *group_family; | |||||
const char *group_name; | |||||
}; | |||||
static struct genl_group groups[MAX_GROUPS]; | |||||
static int dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr, | |||||
const struct genl_family *gf, struct nl_writer *nw); | |||||
static void nlctrl_notify(const struct genl_family *gf, int action); | |||||
static struct genl_family * | |||||
find_family(const char *family_name) | |||||
{ | |||||
for (int i = 0; i < MAX_FAMILIES; i++) { | |||||
struct genl_family *gf = &families[i]; | |||||
if (gf->family_name != NULL && !strcmp(gf->family_name, family_name)) | |||||
return (gf); | |||||
} | |||||
return (NULL); | |||||
} | |||||
uint32_t | |||||
genl_register_family(const char *family_name, size_t hdrsize, int family_version, | |||||
int max_attr_idx) | |||||
{ | |||||
uint32_t family_id = 0; | |||||
MPASS(family_name != NULL); | |||||
if (find_family(family_name) != NULL) | |||||
return (0); | |||||
GENL_LOCK(); | |||||
for (int i = 0; i < MAX_FAMILIES; i++) { | |||||
struct genl_family *gf = &families[i]; | |||||
if (gf->family_name == NULL) { | |||||
gf->family_name = family_name; | |||||
gf->family_version = family_version; | |||||
gf->family_hdrsize = hdrsize; | |||||
gf->family_attr_max = max_attr_idx; | |||||
gf->family_id = i + GENL_MIN_ID; | |||||
NL_LOG(LOG_DEBUG2, "Registered family %s id %d", | |||||
gf->family_name, gf->family_id); | |||||
family_id = gf->family_id; | |||||
nlctrl_notify(gf, CTRL_CMD_NEWFAMILY); | |||||
break; | |||||
} | |||||
} | |||||
GENL_UNLOCK(); | |||||
return (family_id); | |||||
} | |||||
static void | |||||
free_family(struct genl_family *gf) | |||||
{ | |||||
if (gf->family_cmds != NULL) | |||||
free(gf->family_cmds, M_NETLINK); | |||||
} | |||||
/* | |||||
* Can sleep, I guess | |||||
*/ | |||||
bool | |||||
genl_unregister_family(const char *family_name) | |||||
{ | |||||
bool found = false; | |||||
GENL_LOCK(); | |||||
struct genl_family *gf = find_family(family_name); | |||||
nlctrl_notify(gf, CTRL_CMD_DELFAMILY); | |||||
if (gf != NULL) { | |||||
found = true; | |||||
/* TODO: zero pointer first */ | |||||
free_family(gf); | |||||
bzero(gf, sizeof(*gf)); | |||||
} | |||||
GENL_UNLOCK(); | |||||
return (found); | |||||
} | |||||
bool | |||||
genl_register_cmds(const char *family_name, const struct genl_cmd *cmds, int count) | |||||
{ | |||||
GENL_LOCK(); | |||||
struct genl_family *gf = find_family(family_name); | |||||
if (gf == NULL) { | |||||
GENL_UNLOCK(); | |||||
return (false); | |||||
} | |||||
int cmd_size = gf->family_cmd_size; | |||||
for (int i = 0; i < count; i++) { | |||||
MPASS(cmds[i].cmd_cb != NULL); | |||||
if (cmds[i].cmd_num >= cmd_size) | |||||
cmd_size = cmds[i].cmd_num + 1; | |||||
} | |||||
if (cmd_size > gf->family_cmd_size) { | |||||
/* need to realloc */ | |||||
size_t sz = cmd_size * sizeof(struct genl_cmd); | |||||
void *data = malloc(sz, M_NETLINK, M_WAITOK | M_ZERO); | |||||
memcpy(data, gf->family_cmds, gf->family_cmd_size * sizeof(struct genl_cmd)); | |||||
void *old_data = gf->family_cmds; | |||||
gf->family_cmds = data; | |||||
gf->family_cmd_size = cmd_size; | |||||
free(old_data, M_NETLINK); | |||||
} | |||||
for (int i = 0; i < count; i++) { | |||||
const struct genl_cmd *cmd = &cmds[i]; | |||||
MPASS(gf->family_cmds[cmd->cmd_num].cmd_cb == NULL); | |||||
gf->family_cmds[cmd->cmd_num] = cmds[i]; | |||||
NL_LOG(LOG_DEBUG2, "Adding cmd %s(%d) to family %s", | |||||
cmd->cmd_name, cmd->cmd_num, gf->family_name); | |||||
} | |||||
GENL_UNLOCK(); | |||||
return (true); | |||||
} | |||||
static struct genl_group * | |||||
find_group(const struct genl_family *gf, const char *group_name) | |||||
{ | |||||
for (int i = 0; i < MAX_GROUPS; i++) { | |||||
struct genl_group *gg = &groups[i]; | |||||
if (gg->group_family == gf && !strcmp(gg->group_name, group_name)) | |||||
return (gg); | |||||
} | |||||
return (NULL); | |||||
} | |||||
uint32_t | |||||
genl_register_group(const char *family_name, const char *group_name) | |||||
{ | |||||
uint32_t group_id = 0; | |||||
MPASS(family_name != NULL); | |||||
MPASS(group_name != NULL); | |||||
GENL_LOCK(); | |||||
struct genl_family *gf = find_family(family_name); | |||||
if (gf == NULL || find_group(gf, group_name) != NULL) { | |||||
GENL_UNLOCK(); | |||||
return (0); | |||||
} | |||||
for (int i = 0; i < MAX_GROUPS; i++) { | |||||
struct genl_group *gg = &groups[i]; | |||||
if (gg->group_family == NULL) { | |||||
gf->family_num_groups++; | |||||
gg->group_family = gf; | |||||
gg->group_name = group_name; | |||||
group_id = i + MIN_GROUP_NUM; | |||||
break; | |||||
} | |||||
} | |||||
GENL_UNLOCK(); | |||||
return (group_id); | |||||
} | |||||
/* | |||||
* Handler called by netlink subsystem when matching netlink message is received | |||||
*/ | |||||
static int | |||||
genl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt) | |||||
{ | |||||
struct nlpcb *nlp = npt->nlp; | |||||
int error = 0; | |||||
int family_id = (int)hdr->nlmsg_type - GENL_MIN_ID; | |||||
if (__predict_false(family_id < 0 || family_id > MAX_FAMILIES)) { | |||||
NLP_LOG(LOG_DEBUG, nlp, "invalid message type: %d", hdr->nlmsg_type); | |||||
return (ENOTSUP); | |||||
} | |||||
if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) { | |||||
NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len); | |||||
return (EINVAL); | |||||
} | |||||
struct genl_family *gf = &families[family_id]; | |||||
struct genlmsghdr *ghdr = (struct genlmsghdr *)(hdr + 1); | |||||
if (ghdr->cmd >= gf->family_cmd_size || gf->family_cmds[ghdr->cmd].cmd_cb == NULL) { | |||||
NLP_LOG(LOG_DEBUG, nlp, "family %s: invalid cmd %d", | |||||
gf->family_name, ghdr->cmd); | |||||
return (ENOTSUP); | |||||
} | |||||
struct genl_cmd *cmd = &gf->family_cmds[ghdr->cmd]; | |||||
if (cmd->cmd_priv != 0 && !nlp_has_priv(nlp, cmd->cmd_priv)) { | |||||
NLP_LOG(LOG_DEBUG, nlp, "family %s: cmd %d priv_check() failed", | |||||
gf->family_name, ghdr->cmd); | |||||
return (EPERM); | |||||
} | |||||
NLP_LOG(LOG_DEBUG2, nlp, "received family %s cmd %s(%d) len %d", | |||||
gf->family_name, cmd->cmd_name, ghdr->cmd, hdr->nlmsg_len); | |||||
error = cmd->cmd_cb(hdr, npt); | |||||
return (error); | |||||
} | |||||
static uint32_t | |||||
get_cmd_flags(const struct genl_cmd *cmd) | |||||
{ | |||||
uint32_t flags = cmd->cmd_flags; | |||||
if (cmd->cmd_priv != 0) | |||||
flags |= GENL_ADMIN_PERM; | |||||
return (flags); | |||||
} | |||||
static int | |||||
dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr, | |||||
const struct genl_family *gf, struct nl_writer *nw) | |||||
{ | |||||
if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) | |||||
goto enomem; | |||||
struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr); | |||||
ghdr_new->cmd = ghdr->cmd; | |||||
ghdr_new->version = gf->family_version; | |||||
ghdr_new->reserved = 0; | |||||
nlattr_add_string(nw, CTRL_ATTR_FAMILY_NAME, gf->family_name); | |||||
nlattr_add_u16(nw, CTRL_ATTR_FAMILY_ID, gf->family_id); | |||||
nlattr_add_u32(nw, CTRL_ATTR_VERSION, gf->family_version); | |||||
nlattr_add_u32(nw, CTRL_ATTR_HDRSIZE, gf->family_hdrsize); | |||||
nlattr_add_u32(nw, CTRL_ATTR_MAXATTR, gf->family_attr_max); | |||||
if (gf->family_cmd_size > 0) { | |||||
int off = nlattr_add_nested(nw, CTRL_ATTR_OPS); | |||||
if (off == 0) | |||||
goto enomem; | |||||
for (int i = 0, cnt=0; i < gf->family_cmd_size; i++) { | |||||
struct genl_cmd *cmd = &gf->family_cmds[i]; | |||||
if (cmd->cmd_cb == NULL) | |||||
continue; | |||||
int cmd_off = nlattr_add_nested(nw, ++cnt); | |||||
if (cmd_off == 0) | |||||
goto enomem; | |||||
nlattr_add_u32(nw, CTRL_ATTR_OP_ID, cmd->cmd_num); | |||||
nlattr_add_u32(nw, CTRL_ATTR_OP_FLAGS, get_cmd_flags(cmd)); | |||||
nlattr_set_len(nw, cmd_off); | |||||
} | |||||
nlattr_set_len(nw, off); | |||||
} | |||||
if (gf->family_num_groups > 0) { | |||||
int off = nlattr_add_nested(nw, CTRL_ATTR_MCAST_GROUPS); | |||||
if (off == 0) | |||||
goto enomem; | |||||
for (int i = 0, cnt = 0; i < MAX_GROUPS; i++) { | |||||
struct genl_group *gg = &groups[i]; | |||||
if (gg->group_family != gf) | |||||
continue; | |||||
int cmd_off = nlattr_add_nested(nw, ++cnt); | |||||
if (cmd_off == 0) | |||||
goto enomem; | |||||
nlattr_add_u32(nw, CTRL_ATTR_MCAST_GRP_ID, i + MIN_GROUP_NUM); | |||||
nlattr_add_string(nw, CTRL_ATTR_MCAST_GRP_NAME, gg->group_name); | |||||
nlattr_set_len(nw, cmd_off); | |||||
} | |||||
nlattr_set_len(nw, off); | |||||
} | |||||
if (nlmsg_end(nw)) | |||||
return (0); | |||||
enomem: | |||||
NL_LOG(LOG_DEBUG, "unable to dump family %s state (ENOMEM)", gf->family_name); | |||||
nlmsg_abort(nw); | |||||
return (ENOMEM); | |||||
} | |||||
/* Declare ourself as a user */ | |||||
#define CTRL_FAMILY_NAME "nlctrl" | |||||
static uint32_t ctrl_family_id; | |||||
static uint32_t ctrl_group_id; | |||||
struct nl_parsed_family { | |||||
uint32_t family_id; | |||||
char *family_name; | |||||
uint8_t version; | |||||
}; | |||||
#define _IN(_field) offsetof(struct genlmsghdr, _field) | |||||
#define _OUT(_field) offsetof(struct nl_parsed_family, _field) | |||||
static const struct nlfield_parser nlf_p_generic[] = { | |||||
{ .off_in = _IN(version), .off_out = _OUT(version), .cb = nlf_get_u8 }, | |||||
}; | |||||
static struct nlattr_parser nla_p_generic[] = { | |||||
{ .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(family_id), .cb = nlattr_get_uint32 }, | |||||
{ .type = CTRL_ATTR_FAMILY_NAME , .off = _OUT(family_id), .cb = nlattr_get_string }, | |||||
}; | |||||
#undef _IN | |||||
#undef _OUT | |||||
NL_DECLARE_PARSER(genl_parser, struct genlmsghdr, nlf_p_generic, nla_p_generic); | |||||
static int | |||||
nlctrl_handle_getfamily(struct nlmsghdr *hdr, struct nl_pstate *npt) | |||||
{ | |||||
int error = 0; | |||||
struct nl_parsed_family attrs = {}; | |||||
error = nl_parse_nlmsg(hdr, &genl_parser, npt, &attrs); | |||||
if (error != 0) | |||||
return (error); | |||||
struct genlmsghdr ghdr = { | |||||
.cmd = CTRL_CMD_NEWFAMILY, | |||||
}; | |||||
for (int i = 0; i < MAX_FAMILIES; i++) { | |||||
struct genl_family *gf = &families[i]; | |||||
if (gf->family_name == NULL) | |||||
continue; | |||||
if (attrs.family_id != 0 && attrs.family_id != gf->family_id) | |||||
continue; | |||||
if (attrs.family_name != NULL && strcmp(attrs.family_name, gf->family_name)) | |||||
continue; | |||||
error = dump_family(hdr, &ghdr, &families[i], npt->nw); | |||||
if (error != 0) | |||||
break; | |||||
} | |||||
return (error); | |||||
} | |||||
static void | |||||
nlctrl_notify(const struct genl_family *gf, int cmd) | |||||
{ | |||||
struct nlmsghdr hdr = {.nlmsg_type = NETLINK_GENERIC }; | |||||
struct genlmsghdr ghdr = { .cmd = cmd }; | |||||
struct nl_writer nw = {}; | |||||
if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_GENERIC, ctrl_group_id)) { | |||||
dump_family(&hdr, &ghdr, gf, &nw); | |||||
nlmsg_flush(&nw); | |||||
return; | |||||
} | |||||
NL_LOG(LOG_DEBUG, "error allocating group writer"); | |||||
} | |||||
static const struct genl_cmd nlctrl_cmds[] = { | |||||
{ | |||||
.cmd_num = CTRL_CMD_GETFAMILY, | |||||
.cmd_name = "GETFAMILY", | |||||
.cmd_cb = nlctrl_handle_getfamily, | |||||
.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP, GENL_CMD_CAP_HASPOL, | |||||
}, | |||||
}; | |||||
static void | |||||
genl_nlctrl_init() | |||||
{ | |||||
ctrl_family_id = genl_register_family(CTRL_FAMILY_NAME, 0, 2, CTRL_ATTR_MAX); | |||||
genl_register_cmds(CTRL_FAMILY_NAME, nlctrl_cmds, NL_ARRAY_LEN(nlctrl_cmds)); | |||||
ctrl_group_id = genl_register_group(CTRL_FAMILY_NAME, "notify"); | |||||
} | |||||
static void | |||||
genl_nlctrl_destroy() | |||||
{ | |||||
genl_unregister_family(CTRL_FAMILY_NAME); | |||||
} | |||||
static const struct nlhdr_parser *all_parsers[] = { &genl_parser }; | |||||
static void | |||||
genl_load(void *u __unused) | |||||
{ | |||||
GENL_LOCK_INIT(); | |||||
NL_VERIFY_PARSERS(all_parsers); | |||||
netlink_register_proto(NETLINK_GENERIC, "NETLINK_GENERIC", genl_handle_message); | |||||
genl_nlctrl_init(); | |||||
} | |||||
SYSINIT(genl_load, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_load, NULL); | |||||
static void | |||||
genl_unload(void *u __unused) | |||||
{ | |||||
genl_nlctrl_destroy(); | |||||
GENL_LOCK_DESTROY(); | |||||
epoch_wait_preempt(net_epoch_preempt); | |||||
} | |||||
SYSUNINIT(genl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_unload, NULL); |